Tinian Monarch SSA Version 1.0

Species Status Assessment Report for the Tinian Monarch (Monarcha takatsukasae)

Tinian Monarch nest at the Santa Lourdes Shrine, March 2007. Photo by Eric VanderWerf

U.S. Fish & Wildlife Service Pacific Islands Fish and Wildlife Office

Version 1.0 March 2018

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Suggested citation:

U.S. Fish and Wildlife Service. 2018. Species status assessment for the Tinian Monarch. Version 1.0, March 2018. U.S. Fish and Wildlife Service, Pacific Islands Fish and Wildlife Office, Honolulu, HI.

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Executive Summary Introduction The Tinian Monarch is a small flycatcher bird endemic to the 39-mi2 (101 km2) island of Tinian, the second largest island in the Commonwealth of the Northern Mariana Islands (CNMI), in the western Pacific Ocean. In 1970, the United States Fish & Wildlife Service (Service) listed the Tinian Monarch as an endangered species under the Endangered Species Act of 1973, as amended (16 U.S.C. 1531 et seq). In 1987, the Service downlisted the Tinian Monarch to a threatened status, and in 2004, it was removed from the list of threatened species. In 2013, the Service was petitioned to list the Tinian Monarch as an endangered or threatened species under the Act, and as a result, the Service began a full review of the species’ status using the Species Status Assessment (SSA) approach. The SSA will serve as the foundational science for informing the Service’s decision whether or not to list the Tinian Monarch. This SSA report assesses the species’ ecology, current condition, and future condition under various scenarios.

The Tinian Monarch is an arboreal bird that inhabits forested areas of the island. The forest on Tinian is broadly divided into three types—native (limestone), secondary-mixed, and tangantangan (Leucaena leucocephala), which together comprises approximately 64% of the island’s land cover. Studies of the ecology and life history of the bird indicate that while the Tinian Monarch thrives in all three forest types, its ecology and behaviors do vary among the forests. Specifically, the Monarch lives in higher densities in the native forest, which comprises approximately 8% of the island’s forest cover (5% of the total land cover), and also has a higher nesting rate, density, and success in this forest. We have identified the basic needs of individuals and for the population and species as a whole as follows:

Individual Needs • Shelter, prey for foraging (insects), and breeding sites, all of which are provided by forest habitat of sufficient density.

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Population/ Species Needs • Forest habitat of sufficient area and continuity to accommodate home range and breeding territories. • Forest habitat continuity / connectivity to accommodate island-wide population distribution and dispersal. • Low abundance of existing predators and prevention of the establishment of new, invasive predators like the brown treesnake.

Executive Summary – Current Condition

Historically, human activities have drastically altered Tinian’s landscape including the amount of forest habitat on the island available to the Monarch. Impacts to the forests of Tinian began with the arrival of the original Chamorro people 3,000-4000 ago and increased following European colonization in the 1500s. By the conclusion of the Second World War (WWII), human activities on the island had seriously reduced what was originally extensive native forest habitat to tiny remnants. Following the end of WWII and until the 1990s, there was a steady and significant regrowth of forest with some periodic fluctuations in total forest cover, accompanied by substantial change in composition. Beginning in the 1980s through a long-term lease with the CNMI government, the United States Navy (U.S. Navy) has occasionally conducted exercises of variable scale (up to 2,000 personnel (U.S. Pacific Command 1999, pp. 2-11, 3-37)) in the northern two-thirds of Tinian and involving occasional use of WWII structures and clearing of tangantangan from old runways. Today, most (approximately 92%) of the forest on Tinian is comprised of mixed-secondary vegetation and the invasive tangantangan.

During the aforementioned loss of forest habitat which began with the arrival of human settlers to the island and culminating with the largest extent of forest reduction preceding and during the WWII, the Tinian Monarch population had experienced a drastic decline, possibly less than 80% of the current population level. Since the end of WWII, the Monarch population has increased to a current population size of almost 100,000 individuals in conjunction with a substantial rebound in forest growth. This exemplified the highly resilient nature of the Tinian Monarch in the face of drastic changes to the habitat upon which it depends. Currently, periodic forest habitat loss alone is not having a significantly measurable impact to the overall condition of the species. In

4 Tinian Monarch SSA Version 1.0 addition to habitat loss, we also explored other factors that may influence the current viability of the Tinian Monarch, including typhoons, drought, cattle ranching, and predation, among others. However, we found no evidence that these factors were having a measureable impact to individuals or the species as a whole.

Executive Summary – Future Condition

When assessing possible future conditions of the Tinian Monarch, we looked primarily to potential impacts from:

1) The introduction of a potential invasive predator, the brown treesnake (BTS), on Tinian – Based on our knowledge of impacts to Guam from the BTS, we believe its establishment on Tinian would likely result in the decimation or extirpation of the Tinian Monarch. Movement of civilian and military cargo and other materials that may contain BTS stowaways from Guam to the CNMI poses an enormous risk to Tinian and interdiction efforts are in place on both Guam and within the CMNI to prevent such a scenario. Despite improvements and advances in interdiction efforts, especially by the U.S. Navy, the risk of the invasive BTS remains high. 2) Future military activities on Tinian that may degrade or reduce forest habitat – The U.S. Navy has proposed future development activities, which may impact the Monarch according to their own assessment. Based on these plans, both the U.S. Navy and the Service assessed that approximately 11% of Tinian’s forest habitat will be lost, leading to approximately 8% of the Monarch population being permanently displaced (unable to reproduce) due to the reduction in the number of breeding territories (see Section 2.2.3 regarding about the Monarch’s territoriality). 3) Future civilian activities that may also degrade or reduce forest habitat through development – Based on rates of development in recent history and the CNMI’s stated interested in future developments on Tinian, we anticipate 4-6 development projects of a given size and involving the construction of permanent structures will occur over the next 16-66 years. Each project would cause the loss of approximately 2% of Tinian’s forest, leading to indefinite displacement (no reproduction) of approximately 1% of the Monarch population.

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4) Military and civilian activities that increase the risk of wildfire – Based on our projections of future military and civilian activities, the risk of wildfire in the future varies from little or no increase to a substantial increase, depending on numerous specificities of the activities.

We summarize these potential future impacts in five scenarios of the Tinian Monarch’s future condition.

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Abbreviations and Acronyms

3Rs = Resiliency, Representation, and Redundancy ac = acres ADS = aerial bait delivery systems AAFB = Andersen Air Force Base BBS = Breeding Bird Survey BO = biological opinion BTS = Brown treesnake BTSWG = Brown Treesnake (Technical) Working Group CJMT = Commonwealth of the Northern Mariana Islands Joint Military Training cm = centimeters CNMI = Commonwealth of the Northern Mariana Islands DEIS = Draft Environmental Impact Statement DFW = Division of Fish and Wildlife Divert = United States Air Force Divert Activities and Exercises DLNR = Commonwealth of the Northern Mariana Islands Department of Lands and Natural Resources DOD = Department of Defense DOI = Department of the Interior EDRR = early detection and rapid response EIS = Environmental Impact Statement EMUA = Exclusive Military Use Area ESA = Endangered Species Act FDM = Farallon de Medinilla FEMA = Federal Emergency Management Agency FAA = Federal Aviation Administration ft = feet GISD = Global Invasive Species Database ha = hectares IUCN = International Union for Conservation of Nature in = inches km / km2 = kilometers / square kilometers LBA = Leaseback Area m = meters mi / mi2 = miles / square miles MITT = Mariana Islands Training and Testing Area MIRC = Mariana Islands Range Complex MLA = Military Lease Area NISC = National Invasive Species Council OIA – Office of Insular Affairs RBP = Regional Biosecurity Plan for Micronesia and Hawaii SE = Standard Error Service = United States Fish & Wildlife Service SSA = Species Status Assessment USAF = United States Air Force

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U.S. Navy = United States Navy USDA-APHIS = United States Department of Agriculture Animal and Plant Health Inspection Services USFWS = United States Fish & Wildlife Service USGS = United States Geological Survey WWII = World War II (Second World War)

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Table of Contents Executive Summary ...... 3

Introduction ...... 3

Abbreviations and Acronyms ...... 7

Table of Contents ...... 9

List of Figures ...... 12

List of Tables ...... 16

Chapter One: Introduction ...... 18

1.1 The Species Status Assessment (SSA) and Methodology ...... 21

1.1.1 The SSA Framework...... 21

1.2 Data and Other Methods Used ...... 23

Chapter Two: Species Ecology ...... 24

2.1 The Tinian Monarch ...... 25

2.1.1 Taxonomy ...... 25

2.1.2 Morphological description ...... 26

2.1.3 Sexing ...... 27

2.1.4 Forest habitat description ...... 27

2.2 Life Cycle and Individual Needs ...... 30

2.2.1 Life span, mating cycles, nest building, and brooding ...... 35

2.2.2 Foraging behaviors...... 42

2.2.3 Territoriality, territory, home range, and turnover rates ...... 43

2.2.4 Home-Range Sizes ...... 46

2.2.5 Densities ...... 48

2.3 Population / Species Needs ...... 51

2.3.1 Resiliency ...... 52

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2.3.2 Representation and Redundancy ...... 53

Chapter Three: Current Condition ...... 56

3.1 Tinian Monarch Distribution and Abundance ...... 56

3.1.1 From 1945–1976 ...... 56

3.1.2 From 1982–2013 ...... 61

3.1.3 Summary ...... 70

3.2 Factors Influencing Current Viability ...... 70

3.2.1 Forest Habitat Changes Due to Human Activity over Time ...... 71

3.2.2 Wildfire ...... 79

3.2.3 Other Factors ...... 82

Chapter Four: Future Condition ...... 104

4.1 Factors Influencing Future Viability - Overview ...... 104

4.2 Brown treesnake (BTS)...... 107

4.2.1 Overview ...... 107

4.2.2 The Brown Treesnake ...... 108

4.2.3 Loss of Guam avifauna to BTS predation ...... 113

4.2.4 Guam as springboard for the BTS invasion ...... 117

4.2.5 BTS risk management efforts ...... 118

4.2.6 BTS interdiction funding ...... 119

4.2.7 BTS interdiction tools ...... 121

4.2.8 BTS Interdiction on Guam ...... 129

4.2.9 BTS Interdiction in the CNMI ...... 130

4.2.10 Need for BTS Interdiction for Military Activities on Tinian ...... 132

4.2.11 Summary of BTS interdiction challenges and the lack of a solution for treating an incipient population ...... 142

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4.2.12 A risk assessment model for BTS ...... 147

4.2.13 BTS summary ...... 150

4.3 Future Military Activities – CNMI Joint Military Training ...... 151

4.3.1 Land Alteration and Potential Displacement of the Tinian Monarch ...... 152

4.3.2 Fragmentation ...... 154

4.3.3 Land Alteration Mitigation ...... 154

4.3.4 The Future of Cattle Ranching Under CJMT ...... 155

4.3.5 CJMT and Increased Wildfire Risk ...... 160

4.4 Future Civilian Activities ...... 164

Chapter Five: Future Scenarios ...... 169

5.1 Overview ...... 169

5.2 Tinian Monarch condition under each scenario ...... 171

5.2.1 Scenario One ...... 171

5.2.2 Scenario Two ...... 172

5.2.3 Scenario Three ...... 174

5.2.4 Scenario Four ...... 175

5.2.5 Scenario Five ...... 175

Appendix A – Description of Guguan Island ...... 179

Appendix B – Canopy, Subcanopy, and Understory Species Commonly Found on Tinian ...... 182

Appendix C – List of Directives and Policy Driving the Realignment of US Forces in the Pacific Region Including the CJMT (taken from the 2015 CJMT DEIS) ...... 184

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List of Figures Figure 1. Photograph of juvenile Tinian Monarch (Photograph by Eric VanderWerf) ...... 18 Figure 2. Map of the Mariana Islands Archipelago, including the Commonwealth of the Northern Mariana Islands, showing the island of Tinian bisected by the 15 degree northern latitude line. Located at 15º N, 145º 38' E—Tinian is the third largest island in the Mariana archipelago and is approximately 3.1 mi (5 km) southwest of Saipan (where the CNMI’s capital is located) and 99.4 mi (160 km) northeast of the separate U.S. territory, Guam (Engbring et al. 1986, p. 5)...... 19 Figure 3. Species Status Assessment Framework’s three basic stages...... 22 Figure 4. Conceptual model demonstrating how the habitat and demographic factors of the Tinian Monarch, which incorporate individual- and species-level needs, contribute to the overall viability of the species...... 25 Figure 5. Forest habitat and non-forest distribution on islands of Tinian and Guguan.(Shown at same scale) (Based upon Liu and Fischer 2006, entire)...... 28 Figure 6. Locations of the small-scale study plot sites from the Tinian Monarch post-delisting monitoring studies (2006 to 2011) and the DFW Breeding Bird Survey (BBS) roadside count sites surveyed between 1999 and 2010...... 34 Figure 7. Tinian Monarch nesting activity and rainfall 1994-1995 (from USFWS 1996, p. 30). 36 Figure 8. Photographs showing Tinian Monarch nest construction and egg. (Photographs by Paul Radley)...... 40 Figure 9. Life cycle of the Tinian Monarch...... 41 Figure 10. Annual territory turnover rates for the three study sites on the island of Tinian sampled from 2006–2010. The Seaport site was first sampled in 2007. However, the data for that year was not included in the analysis due to limited sampling...... 45 Figure 11. Average Tinian Monarch territory size per year at three study plots on Tinian. The Seaport site was not monitored in 2007 and the Santa Lourdes and Airport Mitigation Area (Airport) sites were not monitored in 2011. (From Amidon et al. in litt. 2016, p. 12)...... 47 Figure 12. Distance between same-day re-sightings of banded Tinian Monarchs within the three forest habitat types (from USFWS 1996, p. 30). The “Limestone Forest” category refers to the native forest...... 49

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Figure 13. Hand-drawn map by Theodore Downs (1946, p. 90) showing locations of recorded bird observations between June and October of 1946. Tinian Monarch sites of observation are indicated by red circles...... 58 Figure 14. From Marshall 1949, p. 205: “View of part of largest area of undisturbed forest (right center) on Tinian.” ...... 60 Figure 15. Map of Tinian showing transects from all four (1982, 1996, 2008, 2013) island-wide forest bird surveys...... 64 Figure 16. Average Tinian Monarch detections by bird per station (95% CI) during quarterly surveys conducted from 1999–2010. The X-axis shows mean annual bird detections per survey station. Dates are numerical month (e.g., April = 4) and year (from Amidon et al. in litt. 2016, p. 8)...... 69 Figure 17. Mean annual Tinian Monarch detections per survey station from 1999-2017...... 70 Figure 18. Map of Tinian showing the extent of sugar cane cultivation (32.8 square miles) during the Japanese period of colonization on the island (Map from The Seizure of Tinian. USMC Historical Monograph)...... 73 Figure 19. Photograph of the northern third of Tinian looking eastward, showing the massive runway system and the extent of the altered landscape of the Airforce’s North Field during WWII, at the time the largest airport in the world and an area of strategic military significance for the U.S. Lake Hagoi, Tinian’s only body of water, is seen in the foreground...... 75 Figure 20. Map of Tinian showing land owner ship and military lease areas (from the CJMT (CNMI Joint Military Training) DEIS (Draft Environmental Impact Statement), U.S. Navy 2015, p. 3-83)...... 77 Figure 21. Cattle grazing in a pasture in southern Tinian (note invasive Lantana camara in the foreground; photograph by Mike Richardson)...... 88 Figure 22. Feral goat within secondary-mixed forest on the island of Pagan (photograph by Mike Richardson)...... 90 Figure 23. Photograph of black rat gorging on papaya within tangantangan forest on northern Tinian (photograph by Mike Richardson)...... 97 Figure 24. Photograph of adult monitor lizard hiding in dead tree in mixed forest on Pagan (photograph by Mike Richardson)...... 100

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Figure 25. Photograph of pox-like lesions on the foot of a Tinian Monarch captured during the 2006 study (photograph by Eric VanderWerf)...... 102 Figure 26. Conceptual model demonstrating how the anthropogenic and environmental factors considered in our future scenarios influence the habitat and demographic factors of the Tinian Monarch, which contribute to the overall viability of the species...... 106 Figure 27. Photograph of brown treesnake (Boiga irregularis) showing its striking eyes adapted for nocturnal life (photograph by Bjorn Lardner)...... 109 Figure 28. Guam flycatcher (photograph by Anne Maben)...... 116 Figure 29. Photograph of permanent brown treesnake containment and inspection barrier at the seaport on Saipan (currently nonfunctional; photograph by Brand Phillips)...... 123 Figure 30. Photograph of the Commonwealth of the Northern Mariana Islands Division of Fish and Wildlife detector dog team (Paulie and her handler) inspecting cargo on Saipan (photograph by Kevin Donmoyer)...... 125 Figure 31. Photographs of live mice traps in use on the island of Guam. Traps are often secured to containment fencing in this manner (photographs by Brand Phillips)...... 127 Figure 32. Photograph of recent experimental version of the aerial bait delivery system component consisting of dead, baited mouse, delivery tube, and streamer designed to catch in the tree canopy...... 145 Figure 33. Photograph of recent experimental, mechanized version of the aerial bait delivery system as seen from helicopter above a test plot on Guam...... 146 Figure 34. Funding provided by various sources for Brown Treesnake prevention, management and research since efforts began in 1987 (from BTSWG 2016, p. 42)...... 147 Figure 35. Footprint of planned military development defined under Alternative 2 in the Commonwealth of the Northern Mariana Islands Joint Military Training...... 153 Figure 36. Map showing existing land uses on Tinian including areas previously under ranching permit within the Leaseback Area (from the CJMT DEIS, U.S. Navy 2015, p. 3-86, Figure 37-5)...... 156 Figure 37. Map showing cattle ranch lands in 2013 on Tinian both within the Military Leaseback Area and on private lands to the south of the military lease area. (from “Beef Cattle Herd Survey, 2013 Island of Tinian, Commonwealth of the Northern Mariana Islands,” Northern Marianas College, Cooperative Research, Extension and Education Service)...... 158

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Figure 38. Map showing 2014 agricultural lease areas and proposed relocation of agricultural lease areas within the Military Lease Area under the Commonwealth of the Northern Mariana Islands Joint Military Training...... 159 Figure 39. 2017 photograph of billboard advertising a proposed casino resort (currently on hold) to be located near the harbor in San Jose (photograph by Mike Richardson)...... 166 Figure 40. 2017 photographs (looking southwest) showing portions of the areas cleared in 2016 for the Altercity Resort (photographs by Mike Richardson)...... 167 Figure 41. Map of Tinian showing the footprint for two recent civilian development projects in the southern third of the island...... 168 Figure 42. Photograph of Guguan Island (Dick Moore, U.S. Geological Survey)...... 179 Figure 43. Photograph detailing forest habitat distribution on the island of Guguan...... 180 Figure 44. Map comparing Guguan to scale with Tinian and the extent of forest cover on both...... 181

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List of Tables Table 1. Taxonomic classification of the Tinian Monarch (BirdLife International 2016, p. 1). . 26 Table 2. Summary of Tinian Monarch studies that inform our understanding of the bird’s life cycle and needs...... 31 Table 3. Number of Tinian Monarch nests found in native and introduced tree species (from USFWS 1996, p. 28)...... 38 Table 4. Tinian Monarch nesting activity among forest habitat types 1994–1995 (from USFWS 1996, p. 30)...... 39 Table 5. Tinian Monarch reproductive success among the forest habitat types in 1995...... 42 Table 6. Home-range estimates by forest type for Tinian Monarch later observed at least once (from USFWS 1996, p. 38)...... 46 Table 7. Tinian Monarch densities by forest type from 1994–1995...... 48 Table 8. Tinian Monarch density estimates derived from point-transect sampling and territory mapping studies on the island of Tinian. (Territory mapping density estimates were multiplied by two to estimate the number of birds per hectare. Point-transect estimates for Camp et al. 2012 and NAVFAC 2014 are not directly comparable due to differences in data used to derive detection functions. However, all density estimates within NAVFAC 2014 are comparable. Transect analyzed indicates which survey transects were used to derive the density estimates.) 51 Table 9. The 3Rs analysis for examining Tinian Monarch viability...... 55 Table 10. Summary of Tinian Monarch studies that inform our understanding of the species' abundance and distribution...... 61 Table 11. Tinian Monarch surveys, summary of initial and reanalyzed findings...... 65 Table 12. Breeding bird survey roadside count cumulative summary statistics for the Tinian Monarch and Rufous fantail (for comparison), 1999 – 2017 (adapted from DFW in litt. 2017). 69 Table 13. Percent of each forest type and of the Tinian Monarch population found within and outside of the Military Lease Area (MLA)...... 78 Table 14. Species of native birds, lizards, and bats impacted by brown treesnakes on Guam. (Sources: BTSWG 2016, p. 50; Wiles (1987, 2005); Wiles et al.2003, entire) ...... 114 Table 15. Rapid response searches due to credible brown treesnake (BTS) sightings in the Commonwealth of the Northern Mariana Islands (CNMI), 2002 to 2016 (USGS in litt. 2017). 118 Table 16. Outline of scenarios evaluated for the future condition of the Tinian Monarch...... 171

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Table 17. Analysis of Tinian Monarch future conditions under five scenarios over time...... 177

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Figure 1. Photograph of juvenile Tinian Monarch (Photograph by Eric VanderWerf)

Chapter One: Introduction

The Tinian Monarch (Monarcha takatsukasae) is a small flycatcher bird (Figure 1) endemic to the island of Tinian, the second largest island in the Commonwealth of the Northern Mariana Islands (CNMI), located in the western Pacific Ocean (Figure 2). Like most flycatcher species (family Monarchidae), the Tinian Monarch is arboreal; it nests in trees, inhabits forest habitat, and is insectivorous. There are approximately 100,000 Tinian Monarchs distributed widely across the island of Tinian, which is approximately 39-mi2 (101 km2; 25,135.5 ac; 10,172 ha; Figure 5) (Marshall 1949, p. 214; Pratt et al. 1979, p. 231; Engbring et al. 1986, pp. 69–70; USFWS 1996, p. 21; Lusk et al. 2000, pp. 186–187; Camp et al. 2012, pp. 294–295; U.S. Navy 2015, pp. 3-118, 4-220-4-222); Amidon et al. 2016 in litt., p. 8).

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Figure 2. Map of the Mariana Islands Archipelago, including the Commonwealth of the Northern Mariana Islands, showing the island of Tinian bisected by the 15 degree northern latitude line. Located at 15º N, 145º 38' E—Tinian is the third largest island in the Mariana archipelago and is approximately 3.1 mi (5 km) southwest of Saipan (where the CNMI’s capital is located) and 99.4 mi (160 km) northeast of the separate U.S. territory, Guam (Engbring et al. 1986, p. 5).

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Approximately 64% of Tinian is forested, with three general forest types—native (limestone), secondary-mixed, and tangantangan (Liu and Fischer 2006, entire)—and the majority of forested areas on the island are habitat for the Monarch. Tinian’s topography is dominated by a low elevation, plain-like terrain with a few raised limestone plateaus and escarpments, particularly in the northcentral and southeast portions of the island. The highest point on the island, with an elevation of 613.3 ft (187 m), occurs on the island’s southeastern ridge. The climate on Tinian (and across the Mariana Archipelago) is tropical, with a mean temperature of 78º F (26º C) and a mean humidity of 80%. Rainfall averages 80 in (203 cm) per year, with a wetter season from July to October and a drier season from February to April. Tropical storms and typhoons are common predominately during the rainy season, and because of Tinian’s relatively flat terrain, can cause considerable damage to trees and foliage when the island is directly hit (USFWS 1996, pp. 28, 37, 44).

The U.S. Navy leases the northern two-thirds of Tinian, and activities there may extend well into the future both through renewal of the lease and through proposed further development there. The southern third of the island is partially inhabited by civilians, whose presence and extent depends, in part, upon the extent of the island’s military presence. The majority of Tinian’s approximately 3,000 residents live in the only town, San Jose, located at the southwestern edge of the island. Ownership of the island includes a mix of private lands, public Commonwealth lands, although as noted above, the U.S. Navy leases approximately 60 % of the island.

In 2015 and 2016, approximately 100 Tinian Monarchs in total were translocated to Guguan, a small, 1.49-mi2 (3.87 km2), uninhabited island within the CNMI and located approximately 160 mi (257 km) to the north of Tinian (DFW in litt. 2016, pp. 1-2). This project, led by the CNMI Division of Fish and Wildlife (CNMI DFW), introduced the Monarchs to the island of Guguan in an effort to improve the species’ chances of survival under the possibility of brown treesnake becoming established on Tinian. The CNMI DFW has estimated that the island could support between 677 and 923 individuals, while the Service estimated the approximate carrying capacity may range from 530 to 3,620 individuals (CNMI DFW 2013, p. 139).

During surveys on a return trip to Guguan in 2016 to introduce a second group of Monarchs to the island, CNMI DFW staff observed that the birds released in 2015 were actively creating nests

20 Tinian Monarch SSA Version 1.0 and apparently reproducing on some level (DFW in litt. 2016, pp. 1-2), a highly encouraging development. If the Monarchs released onto Guguan grow into a stable and reproducing population we believe it will substantially improve the species’ redundancy even if Guguan Island lacks sufficient carrying capacity to entirely replace a catastrophic loss of the species on Tinian. Nevertheless, we believe it is too early to know whether the Monarchs on Guguan have already grown into a stable population and cannot evaluate the success of the translocation project. Therefore, we do not consider the Guguan monarchs as a second population when examining future possible scenarios or assessing the status of the species as a whole. For more information about Guguan, please see Appendix A.

In 1970, the United States Fish & Wildlife Service listed the Tinian Monarch as an endangered species under the Endangered Species Act of 1973, as amended (16 U.S.C. 1531 et seq; 35 FR 8491). In 1987, the Service downlisted the Tinian Monarch to a threatened status (52 FR 10890), and in 2004, it was removed from the list of threatened species (i.e. delisted) (69 FR 56367). In 2013, the Center for Biological Diversity petitioned the Service to list the Tinian Monarch as an endangered or threatened species under the Act, and in 2015, the Service found that listing the Tinian Monarch may be warranted (80 FR 56423). As a result, the Service began a full review of the species’ status using the Species Status Assessment (SSA) Framework, which will serve as the foundational science for informing the Service’s decision whether or not to list the Tinian Monarch under the Act. This SSA uses the three biological principles of resiliency, representation, and redundancy to assess the species’ ecology, current condition, and future condition under various scenarios.

1.1 The Species Status Assessment (SSA) and Methodology

The SSA is an in-depth review of the species’ biology and threats, an evaluation of its biological status, and an assessment of the resources and conditions needed to maintain populations over time (i.e., viability). To assess Monarch’s viability, we used the three conservation biology principles of resiliency, representation, and redundancy (or the “3Rs,” Shaffer and Stein 2000, pp. 308–311). These principles are described later in this chapter, both in general and in their specific application to the Tinian Monarch.

1.1.1 The SSA Framework

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Our approach for assessing Tinian Monarch viability follows the SSA Framework, as established by the Service in version 3.4, August 2016 (USFWS 2016, entire), and involved three stages (Figure 3). In Stage 1, we identified the ecological requirements for survival and reproduction at the individual, population, and species levels. Also in Stage 1, we defined how the species ecology relates to the 3Rs and thus to the Tinian Monarch’s viability. In Stage 2, we determined the baseline condition of the species using the ecological requirements identified in Stage 1. That is, we assessed the species historical and current condition in relation to the 3Rs and identified past and ongoing factors (risk and beneficial factors) that together make up the species’ current condition. In Stage 3, using the baseline conditions established in Stage 2 and predictions for future impacts on the species, we projected the likely future condition of the Tinian Monarch.

Figure 3. Species Status Assessment Framework’s three basic stages.

1. Species’ Needs. An SSA begins with a compilation of the best available biological information on the species (taxonomy, life history, and habitat) and its ecological needs at the

22 Tinian Monarch SSA Version 1.0 individual, population, and species levels based on how environmental factors are understood to act on the species and its habitat.

2. Current Species’ Condition. Next, an SSA describes the current condition of the species’ habitat and demographics and the probable explanations for past and ongoing changes in abundance and distribution within the species’ ecological settings (i.e., areas representative of the geographic, genetic, or life history variation across the species’ range).

3. Future Species’ Condition. Lastly, an SSA forecasts the species’ response to probable future scenarios of environmental conditions and conservation efforts. As a result, the SSA characterizes species’ ability to sustain populations in the wild over time (viability) based on the best scientific understanding of current and future abundance and distribution within the species’ ecological settings.

Throughout the assessment, the SSA uses the conservation biology principles of resiliency, redundancy, and representation (collectively known as the “3Rs”) as a lens to evaluate the current and future condition of the species. Representation describes the ability of a species to adapt to changing environmental conditions, which is related to distribution within the species’ ecological settings. Resiliency describes the ability of the species to withstand stochastic disturbance events, an ability that is associated with population size, growth rate, and habitat quality. Redundancy describes the ability of a species to withstand catastrophic events, an ability that is related to the number, distribution, and resilience of populations. Together, the 3Rs—and their core autecological parameters of abundance, distribution, and diversity—comprise the key characteristics that contribute to a species’ ability to sustain populations in the wild over time. When combined across populations, they measure the health of the species as a whole.

1.2 Data and Other Methods Used

Data used in our assessment primarily included Tinian Monarch survey data, vegetation mapping, and landuse projections. When specific data about the Tinian Monarch’s ecology and biology or threats to the species and habitat were not available, we used data collected from other localities with similar features, such as the CNMI and Guam.

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Chapter Two: Species Ecology

In this chapter, we review the Tinian Monarch’s ecological needs, the most important of which is dense, connected forest habitat capable of supporting individuals and the island’s population. While the Tinian Monarch is found within all three of Tinian’s forest types—native, secondary- mixed, and tangantangan—the native forest provides the highest quality habitat in terms of nesting preference and structure, breeding habits, reproductive success, smaller home-range sizes, and higher densities. These characteristics are discussed in further detail in this chapter along with review of the available life-history studies. The Tinian Monarch requires insect prey, particularly during the breeding season, and the availabilities of both insect prey and forest habitat are partially dependent upon cyclical periods of rain, sans excessive, catastrophic periods of drought or typhoon seasons. Finally, the Monarch needs a forest environment with a low abundance of most predators and a complete absence of certain invasive predators (such as the brown treesnake).

The primary needs of the Tinian Monarch are listed below and diagramed in Figure 4:

Individual Needs • Shelter, prey for foraging (insects), and breeding sites, all of which are provided by forest habitat of sufficient density.

Population / Species Needs • Forest habitat of sufficient area and continuity to accommodate home range and breeding territories. • Forest habitat continuity / connectivity to accommodate island-wide population distribution.

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• Low abundance of most predators and complete absence of certain invasive predators (e.g., brown treesnake).

Figure 4. Conceptual model demonstrating how the habitat and demographic factors of the Tinian Monarch, which incorporate individual- and species-level needs, contribute to the overall viability of the species.

2.1 The Tinian Monarch

2.1.1 Taxonomy

A Monarch flycatcher in the family Monarchidae, the Tinian Monarch was first described by two Japanese ornithologists, Takatsukasa and Yamashina, who visited Tinian in 1931 to study the island’s bird fauna (Takatsukasa and Yamashina 1931; Table 1). The Tinian Monarch is known

25 Tinian Monarch SSA Version 1.0 as the Chuchurican Tinian in the Chamorro language used by the native inhabitants of Mariana Islands (USFWS 1996 p. 15).

Table 1. Taxonomic classification of the Tinian Monarch (BirdLife International 2016, p. 1). Kingdom Phylum Class Order Family Genus Species

Animalia Chordata Aves Passeriformes Monarchidae Monarcha takatukasae

To date, no studies have been conducted to examine the Tinian Monarch’s genome or genetic diversity, so we have no genetic information for the species. However, blood samples were taken from birds handled during post-delisting monitoring studies which took place between 2006 and 2011 to be used later to sex individuals. These samples are in storage and there are tentative plans to examine them for genetic diversity (Vorsino and Amidon in litt. 2016). Despite our lack of genetic information for the Monarch, we believe it is possible the species, as well as other native species restricted Tinian, experienced a genetic bottleneck during the large contraction of its habitat in the 1940s when forest habitat covered only 5–10% of the island based on World War II (WWII) era photographs, or possibly as little as 2% of the island (Bowers 1950, p. 206).

2.1.2 Morphological description

The Tinian Monarch is relatively small in size, although average for a Monarch flycatcher, with adults measuring approximately 6 in (15 cm) bill to tail. Overall dull in color, it has light rufous underparts, olive-brown upperparts, dark chocolate brown wings and tail, white wing bars, white-edged tail feathers, and a white rump and undertail coverts (Baker 1951). The Monarch has a bold eye-ring, and the sides of the face are buffy-tan (BirdLife International 2016, p. 1). The Monarch has a short two-note call, the sound of which has been described as a squeaky dog toy. Its song is a loudly whistled tee-tee-wheeo, and it also produces a loud, raspy scold (BirdLife International 2016, p. 1). On the island of Tinian, the species that most closely resembles the Monarch is the rufous fantail (Rhipidura rufifrons), which has occurred in similar numbers, (varying by survey), and can be differentiated by its rufous rump, dark underparts, and a white throat. However, it is unlikely that the two species would be confused.

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2.1.3 Sexing

In general, male and female Monarchs, including the Tinian Monarch, differ very little morphologically. While the most reliable method of identifying females in the field is the presence of a brood patch, this characteristic is present only when a female is actively incubating eggs or brooding nestlings. Male Monarchs are generally larger than females, so measurements can also be used to sex Monarchs, although there is some overlap and it may not be possible to use measurements to determine sex in birds of intermediate size. Wing chord appears to differ more than other measurements between males and females and is thus the most reliable morphological measurement to use for sexing, but even wing chord shows some overlap (VanderWerf et al. 2007, p. 6; Amidon et al. in litt. 2016, pp. 9-10). It is also possible to sex Monarchs by observing certain behaviors, including singing, which is done primarily by the male and rarely by the female. However, in general, researchers must rely on the presence of a brood patch or a genetic sample (blood or feather) to determine a Monarch’s sex (Amidon et al. in litt. 2016, pp. 4, 9-10).

2.1.4 Forest habitat description

The Tinian Monarch requires forest habitat for foraging and nesting (Marshall 1949, p. 214; Pratt et al. 1979, p. 231; Engbring et al. 1986, pp. 69–70; USFWS 1996, p. 21; Lusk et al. 2000, pp. 186–187; Camp et al. 2012, pp. 294–295; U.S. Navy 2015, pp. 3-118, 4-220-4-222); Amidon et al. 2016 in litt., p. 8). A description of the three primary forest habitats—native (aka limestone), secondary-mixed (including scrub), and tangantangan—and a map of their distributions on Tinian follow (Figure 5).

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Figure 5. Forest habitat and non-forest distribution on islands of Tinian and Guguan.(Shown at same scale) (Based upon Liu and Fischer 2006, entire).

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The native forest on Tinian consists of the native, woody plants and trees that grow on the limestone substrate. Elsewhere, on the Mariana Islands north of the islands of Saipan and Farallon de Medinilla, where the substrate is volcanic as opposed to limestone, the forest is described as simply native forest. The native forest includes very little ground cover. For a list of canopy, subcanopy, and understory species commonly found in the native forest, see Appendix B.

Of the three forest types, the native forest covers the smallest portion of Tinian (estimated at about 5% Tinian land cover) and is the least widely distributed and connected forest type (Liu and Fischer 2006, entire). Nevertheless, any large-scale reduction in Tinian forest habitat quality, for example conversion of the remaining native forest or secondary forest areas to a less diverse forest type or land cover, would affect the Monarch population locally, result in decreased abundance across the island, and possibly impact the species’ ability to withstand future stochastic events such as prolonged drought or devastation from strong typhoons.

Presently covering approximately 19% of the island’s land area (Liu and Fischer 2006, entire), the secondary-mixed forest on Tinian resulted from the removal of the native forest which began with the arrival of earliest human inhabitants through the end of WWII (Baker 1946, p. 206; Downs 1946, p. 89; Bowers 1950, p. 206; Fosberg 1960, p. 46-48; Engbring et al. 1986, p. 25; Falanruw et al. 1989, pp. 2, 7-8; Mueller-Dombois and Fosberg 1998, p. 262; Russell 1998, p. 98; Lusk et al. 2000, p. 181; Berger et al. 2005, pp. 36–37; Liu and Fischer 2006, entire; CNMI- SWARS 2010, pp. 6−7, 28−29). It occurs where primary vegetation was removed, and is mostly composed of the ironwood tree (Casuarina equisetifolia), introduced shrubs, vines, bamboo (Bambusa spp.), and coarse grasses; and a variety of intermingled native forest plants (Falanruw et al. 1989, pp. 6–9). The understory is usually thick with lantana (Lantana camara), which is often the primary ground-cover species. For other tree species common in this forest habitat, see Appendix B.

Nearly pure stands of tangantangan are recognized as a distinct forest habitat type on Tinian. Native to southeastern Mexico, the species has been introduced and spread around the world since the late 1800s and is now widely naturalized throughout the tropics (Little and Skolmen 1989, p. 144). Because of its rapid growth, and possibly allelochemical attributes (the ability to inhibit surrounding, competing plant growth), once established, it quickly forms dense thickets

29 Tinian Monarch SSA Version 1.0 that crowd out native vegetation (Little and Skolmen 1989, p. 144). Consequently, tangantangan is considered highly invasive in many parts of the world and the tropical Pacific, including the Hawaiian Islands. Indeed, tangantangan is considered one of the 100 worst invasive species worldwide by the Invasive Species Specialist Group of the International Union for Conservation of Nature (IUCN) Species Survival Commission (Global Invasive Species Database (GISD) 2016).

Tangantangan was first observed on Tinian in 1946, although it is uncertain exactly when and how tangantangan was introduced to the Mariana Islands and Tinian, or whether this introduction was intentional or inadvertent (Fosberg 1980, unpublished report, as quoted in Hawaiian Agronomics 1985, pp. II-6-II-7). Tangantangan forms solid, practically pure, closed stands that dominate much of the level and moderately sloping areas on Tinian (U.S. Navy 2010, p. 10-3), including much of the areas planted with sugar cane by the Japanese prior to WWII (Fosberg 1980, unpublished report, as quoted in Hawaiian Agronomics 1985, pp. II-6-II-7). Because tangantangan is particularly high in protein, ranchers typically hold the species in high regard as browse for beef cattle (Hawaiian Agronomics 1985, pp. II-6-II-7; Little and Skolmen 1989, p. 144). The upper canopy is approximately 13–16 ft (4–5 m) high and the understory is mostly open, while the densely scattered tangantangan trunks average 1.6–3.2 in (5–8 cm) in diameter. For other tree species commonly associated with and occurring within the tangantangan forest habitat, see Appendix B.

2.2 Life Cycle and Individual Needs

Tinian Monarchs carry out their entire life cycle in the forest habitat on Tinian. Two primary studies were conducted, which inform our understanding of the ecology of the Monarch (Table 2).

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Table 2. Summary of Tinian Monarch studies that inform our understanding of the bird’s life cycle and needs. Survey Year Type of Study Methodology Agency / Citation Name Life history life history / forest-type study plots, USFWS, funded by the studies 1994– home range / breeding and nesting U.S. Navy / 1995 breeding habits USFWS 1996 success Post-delisting survival, 2006– post-delisting monitoring USFWS / monitoring territory, sex, 2011 small-scale habitat studies Amidon et al. in litt. 2016 health

The first, referred to as the “life history studies,” was conducted between 1994 and 1995 by the Service using funding from the U.S. Navy. It was a broad study of the Tinian Monarch’s life history. Despite this study remaining the most thorough examination of the species’ biology and ecological needs to date, it occurred over a relatively short period of time (less than two years) and we caution overly-broad conclusions from the study’s findings (USFWS 1996, entire). In particular, these studies explored: • Reproduction and basic biology

• Breeding and nesting seasonality and differences in the three forest habitat types

• Home range size and density in the three forest types

• Foraging behavior

• Interspecific and Intraspecific Interactions

The second study was a component of the post-delisting monitoring plan for the species. Following the delisting of the Tinian Monarch in 2004 (69 FR 56367), the Service published a post-delisting monitoring plan for the species (USFWS 2005) as required by section 4(g)(1) of the Act. The Tinian Monarch post-delisting monitoring plan included several recommendations, including improving brown treesnake (BTS) detection and prevention on Tinian, habitat monitoring, and implementing a several-year monitoring study of the species, which took place from 2006 to 2011 through complementary survey methods and study plots (USFWS 2016, entire).

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In entirety, the Tinian Monarch post-delisting monitoring studies took place between 2006 and 2011. Roadside bird counts conforming to the North American Breeding Bird Survey (BBS) protocols (established by the USGS's Patuxent Wildlife Research Center) (Mullin pers comm. 2018), were begun in 1999 were also included as part of the post delisting monitoring effort and are discussed further in section 3.1 “Tinian Monarch distribution and abundance.” Additionally, the post delisting monitoring also included small-scale habitat studies conducted yearly from 2006–2009. These studies reaffirmed some information collected during the 1994-95 life history studies and showed Monarch density and home range size remaining similar in the same native forest study plot across a 15 year time span.

Another important goal of the Tinian Monarch post-delisting monitoring plan was testing and establishing an early warning system for the possibility of BTS introduction to Tinian (see section 4.2 Brown treesnake). Consequently, three habitat study plots were designated for the post delisting monitoring studies to annually measure survival and territory occupancy of individually color-banded Monarchs in areas where the BTS might most likely occur or be introduced onto the island. These high-risk areas consist primarily of seaports and airports, because these are the primary locations for cargo and goods to arrive to the island (i.e., the snake cannot swim from Guam to Tinian, and no bridges connect the islands). Also, military cargo and goods shipped to Tinian typically originate on Guam, the closest known source of BTS. Therefore, Tinian’s airport, seaport, and cargo off-loading zones or staging areas are considered particularly sensitive sites, and the three study plots were established in forest habitat near these areas.

The sites chosen based on the above criteria were the Santa Lourdes Shrine, the Airport Mitigation Area, and a site designated “the Seaport Tangantangan Site” (Figure 6), all three near areas where the BTS might arrive on Tinian. The Santa Lourdes Shrine and the Airport Mitigation Area sites were located in limestone forest, and the third site near the seaport in a stand of secondary-mixed and tangantangan forest due to a lack of native forest in that area. Within all three study plots, a total of 120 captured Monarchs were banded (and sexed when possible), and in some cases, tissue and blood samples were taken. Data collected annually within the study plots included species health (noticeable injuries (e.g., bleeding, broken limbs, etc.), abnormalities (e.g., bill crossing), and pox-like lesions). We looked at all the banded birds

32 Tinian Monarch SSA Version 1.0 and collected blood and/or tissue samples from 57 birds.), morphometric data (wing chord, tail length, bill width, bill length, and tarsus length.), sex ratio, molt and breeding condition, territory size, and survivorship, (Amidon et al. in litt. 2016, pp. 4–5).

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Figure 6. Locations of the small-scale study plot sites from the Tinian Monarch post- delisting monitoring studies (2006 to 2011) and the DFW Breeding Bird Survey (BBS) roadside count sites surveyed between 1999 and 2010.

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Together, these two studies show that despite the presence of Monarchs in all three forest types, there are substantial ecological differences in those that inhabit each type. The native forest provides the highest quality habitat for the Monarch, followed by the secondary-mixed forest and the tangantangan forest, in that order. The value of the native forest to the Monarch is evidenced by the combination of the key findings from the few studies conducted thus far (described in more detail in the following sections below), and include:

(1) home range sizes are 4 to 5 times smaller in the native forest (see Section 2.2.4),

(2) nesting success as measured by fledged young is substantially higher in the native forest (Table 5),

(3) nest density is higher in the native forest (Table 4), and

(4) higher densities of adult Monarchs are observed in the native forest (Table 6).

This section details these findings in addition to other key ecological needs and life cycle characteristics explored in the life history and post-delisting monitoring studies.

2.2.1 Life span, mating cycles, nest building, and brooding

The average life span of Tinian Monarch is unknown, although it is estimated to be approximately 10 years (VanderWerf pers comm. 2016; Figure 9) based upon known life spans for similar and related species of Monarch flycatchers, including the Oahu elepaio, documented to live as long as 10 to 12 years (arkive.org 2016a; 2016b; allaboutbirds.org 2016; animaldiversity.org 2016). Likewise, breeding age has not been established for the Tinian Monarch, but it likely begins at approximately two years of age, similar to what has been documented for better studied Monarch flycatchers (VanderWerf pers. comm. 2016; arkive.org 2016a; 2016b).

The Tinian Monarch breeds year round, but pronounced seasonality in nesting activity related to rainfall levels was noted during the 1994–1995 life history studies (USFWS 1996, p. 28) (Figure 7), and later during the annual post-delisting monitoring studies beginning in 2006 (VanderWerf

35 Tinian Monarch SSA Version 1.0 and Zablan in litt. 2006, p. 4). The 1994-1995 studies identified three peaks in Monarch breeding occurring in September, January, and April-May and which accounted for 69% of the nests found under construction during the study. Later, during the course of the post-delisting monitoring studies and through collaborative discussion between the Service, the CNMI DFW, and U.S. Navy biologists, the Service reassessed the Monarch’s breeding ecology and determined that yearly peak typically occurs in February and March (VanderWerf and Zablan in

litt. 2006, p. 4).

Figure 7. Tinian Monarch nesting activity and rainfall 1994-1995 (from USFWS 1996, p. 30).

Following copulation, mated pairs were observed building a nest within three days and beginning incubation within 7–14 days (USFWS, 1996, p. 31; Figure 8). Male and female Monarchs build

36 Tinian Monarch SSA Version 1.0 an open, cup-shaped nest comprised primarily of dried ironwood needles as well as dried leaves, grasses, vine tendrils, feathers, and lichen, with a final product that is strongly tapered to a rounded bottom and that is often festooned with spider webs, moss, and small down feathers (USFWS, 1996, p. 27; Figure 8). Monarch nests can be easily distinguished from the two most similar looking nests, those made by the bridled white-eye (Zosterops conspicillatus)—which are more bowl-shaped, are supported by fewer branches, and are located further from the main tree trunk—and nests made by the rufous fantail, which have a very shallow bowl and a distinctive, twisted tornado-shaped "beard" that extends from the bottom of the nest (USFWS 1996, pp. 28– 29). Tinian Monarchs typically place their nest low in the forest canopy at the junction of vertically oriented supporting branches, around which the nesting material is often woven. Because monarchs only occasionally reuse existing nests or take materials from old nests, researchers often observation old nests damaged, or knocked to the ground by storms and weather events.

During the 1994–1995 life-history studies of the Tinian Monarch, 116 Tinian Monarch nests were located and measured (52 nests in 1994 and 64 nests in 1995) (USFWS, 1996, p. 27). Measurements of nests showed very consistent nest-structure parameters in all three forest habitats, with only nest height, distance of nest from trunk, and nest tree diameter at (the researcher’s) breast height showing difference among habitats. For example, in the native forest, the distance of the nest from the trunk was almost twice that in the secondary-mixed forest and three times that in the tangantangan forest, due largely to the different structure of the dominant tree species in each forest habitat.

A higher nesting success in native forest among the three forest types during storms and typhoons were reported by the Service (USFWS 1996, pp. 29, 45-46). Possible but unconfirmed explanations for that observed difference include nest position within nesting tree (including distance from trunk), the location of native forests along cliff edges, and the structures of the trees found in the forest types. Nests were documented in 14 species of trees, one species of shrub, and two species of vines (Table 3), with approximately 64% of all nests located in native tree species. Within the native forest, the most selected nesting trees were Mariana custard-apple (Guamia mariannae), Mariana dogbane (Ochrosia mariannensis), and Mariana mahogany (Aglaia mariannensis) accounting for 52% of all the native forest nest trees. Within the

37 Tinian Monarch SSA Version 1.0 secondary-mixed forest, half of all the nests were located in either African tulip-tree (Spathodea campanulata) or lantana. Within the tangantangan forest, 62% of the nests were in tangantangan (USFWS, 1996, p. 27).

Table 3. Number of Tinian Monarch nests found in native and introduced tree species (from USFWS 1996, p. 28). # in # in # in Native / Secondary- Species Limestone Tangantangan introduced mixed forest forest forest 1 Acacia confusa I 1 2 0 2 Aglaia mariannensis N 10 0 0 3 Bauhinia monandra I 0 1 0 4 Cynometra ramiflora N 4 0 1 5 Ficus tinctoria N 8 1 0 6 Guamia mariannae N 21 0 0 7 Hibiscus tiliaceus N 2 0 0 8 Lantana camara I 0 5 0 9 Leucaena leucocephala I 1 0 16 Melanolepis 10 N 0 0 4 multiglandulosa 11 Morinda citrifolia N 0 0 2 12 Ochrosia mariannensis N 11 0 1 13 Pithecellobium dulce I 0 1 1 14 Premna obtusifolia N 0 2 0 15 Spathodea campanulata I 1 8 0 16 Unidentified trees n/a 1 3 0 17 Unidentified vines n/a 2 3 1 Total number of nests 62 26 26 N= Native tree species, I = introduced species.

Monarch nest-building activities appear to vary depending on the forest type inhabited by the individual. During the 1994-95 life history studies, Monarchs were observed building nests year- round in native forests, but within the secondary-mixed and tangantangan forests, nest building only occurred prior to the wet season. The researchers hypothesized that this behavior corresponded to lower insect prey abundance in secondary and tangantangan forests during the dry season (USFWS 1996, p. 29). The same study found that active nests in one of three stages

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(building, eggs, or nestlings) occurred in the native forest twice as frequently as in the secondary-mixed forest and four times as frequently as in the tangantangan forest despite the native forest study plot being less than half the size of the other two study plots (Table 4).

Table 4. Tinian Monarch nesting activity among forest habitat types 1994–1995 (from USFWS 1996, p. 30). Number of nests in Number of nests in Number of nests in Nest stage secondary-mixed tangantangan native forest * forest** forest** Building stage 16 12 4 nests

Incubation stage 27 12 5

Nestling stage 13 3 3

Totals 56 27 12 Density of nests with nestlings 3.25 nests per acre .375 nests per acre .375 nests per acre per acre by forest type *The native forest size was 4 ac (1.6 ha) **Both the secondary-mixed and the tangantangan forest study plots were 7.4 ac (3 ha) in size

Documented clutch size for the Tinian Monarch varies from one–three eggs with a mean of two eggs, with the duration of incubation lasting approximately 15 days (USFWS 1996, p. 32). On average, the eggs measure 0.76 in (19.2 mm) in length and 0.57 in (14.4 mm) in width and are whitish in color with pale reddish-brown spots distributed around the surface (USFWS 1996, p. 30). As with nest construction, male and female Monarchs share incubation duties. However, after the eggs hatch, some dichotomy in brooding behavior has been observed, with one adult or the other tending to the hatchlings while its mate brings food to the brooding bird, which either ingests the food or feeds the young. Unfortunately, our observations from this 1994-1995 study did not include banded (sexed) birds; therefore, we do not know if the female or the male assumes brooding during feeding (USFWS 1996, p. 32). As nestlings age, the amount of time adults spend brooding decreases, so that when nestlings reach four–five days, the brooding adult spends less than 50% of its time at the nest during daylight hours (USFWS 1996, p. 32).

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By nine days, Monarch nestlings become active during the daytime, even attempting to climb onto the nest edge, despite having undeveloped wing feathers. By 11 days nestlings appear fully feathered, and by 13 days some nestlings have been observed fledging (USFWS 1996, p. 33). Adults provide the fledgling with constant attention during the first day of fledging and have been observed feeding their young for up to eight weeks after they leave the nest. Young nestlings fledge from nests roughly one month after nest initiation (selection of and construction of the nest) (USFWS 1996, pp. 31-32).

Figure 8. Photographs showing Tinian Monarch nest construction and egg. (Photographs by Paul Radley).

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Figure 9. Life cycle of the Tinian Monarch.

According to the single study that closely examined their life history, Tinian Monarchs appear to exhibit higher reproductive success in the native forest habitat as indicated by both the number of nests and the ratio of completed nest cycles (USFWS 1996, p. 29). That study’s analysis for Tinian Monarch reproductive success was based on 31 nests found under construction in life- history study plots from January 1995 to August 1995, during which differences in reproductive outcomes were noted among the forest types (Table 5). This difference in reproductive success occurred despite the native forest study plot being nearly 2.5 times smaller compared to study plots in the other two forest types (USFWS 1996, pp. 29). As noted in section 3.3.1 below, several typhoons impacted Tinian in 1994, so the observed nesting differences between the three forests results may have been anomalous. Nevertheless, during the dry season of 1995, the authors additionally noted that the foliage in the native forest was less affected by the lack of

41 Tinian Monarch SSA Version 1.0 moisture compared to foliage within the other two forest types (USFWS 1996, p. 37), possibly contributing to the higher nesting success observed there.

Table 5. Tinian Monarch reproductive success among the forest habitat types in 1995. Secondary-Mixed Tangantangan Nesting Stages in Native Forest Total Forest Forest Study Plots # / % # / % # / % Under 19 / 61.29% 9 / 29.03% 3 / 9.68% 31 construction With eggs 19 / 67.86% 9 / 32.14% 0 / 0% 28 With nestlings 6 / 85.71% 1 / 14.29% 0 / 0% 7 With fledglings 6 / 100%* 0 / 0% 0 / 0% 6 * The 6 nests yielded 11 fledglings.

2.2.2 Foraging behaviors

Aside from a single observation of a bird eating a small 1 in (2.5 cm) lizard (USFWS 1996, p. 36), the Tinian Monarch is considered an insectivorous species. Based on observations of intercepted food brought to incubating adult Monarchs or nestlings, prey generally consist of moths, butterflies, ants, caterpillars, and several long-legged insects (Marshall 1949, p. 214; USFWS 1996, p. 36). In all three forest types Tinian Monarchs most commonly forage singly or in mated pairs, but have been observed foraging in small flocks of three–five birds in the secondary-mixed and tangantangan forests (USFWS 1996, p. 35).

Monarchs use several different foraging techniques (as defined by Craig 1989, p. 189), including gleaning (removing prey from a surface while perched), probing (thrusting the bill into a crevice, fruit, or flower), hovering (removing prey from a surface while flying stationary above it), and sallying (capturing flying prey by darting from a perch). Monarchs generally forage at mid-level in the forest understory, but in the shrub habitat they forage closer to the ground and occasionally on it. Among the three forest types, Monarchs use similar foraging surfaces and foraging methods (USFWS 1996, p. 35), but the foraging range is greatest in the secondary-mixed forest because the tree height is taller compared to the native and tangantangan forests where most foraging by the Monarch is done from 6.6–16.4 ft (two and five m) (USFWS 1996, p. 35).

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2.2.3 Territoriality, territory, home range, and turnover rates

The Tinian Monarch has been identified as one among several species of birds on the island of Tinian that exhibit territorial behavior (Engbring et al. 1986, p. 69; USFWS 1996, p. 34; U.S. Navy 2015, pp. 4-200, 4-221; Amidon et al. in litt. 2016, pp. 5, 11-12). The Monarch’s territorial behavior was a focal component of past studies of the species conducted in the mid-1990s and 2000s (see Sections 2.2 and 3.1.2 for additional detail about these studies). During these studies, the Monarch’s territory and home range were examined and provided information about the species’ survivorship, intraspecific interactions, and ecological success in different forest habitat types. Because territoriality is tied to habitat capacity and species abundance, it is important to this assessment and is fundamental in understanding the Tinian Monarch’s current condition and in making projections about its future viability under different scenarios (see Section 5.2). For most animal species, and particularly within island ecosystems, available but unoccupied habitat is rare (if it does exist, it is generally very low-quality habitat) and especially when populations (or species) are limited by habitat, and not by predators, disease, or over-hunting (U.S. Navy 2015, pp. 4-200, 4-221).

Much has been written about the concept of avian territoriality beginning in at least the third and second centuries, B.C, in writings by Aristotle and Zenodotus, and later, particularly in the 20th Century (Lack 1946, pp. 108-109). Following the publication of Margaret Nice’s 1941 article, “The role of territory in bird life”, which described territory types, a large amount of the focus has concerned how the behavior may affect the reproductive capacity and thus abundance of different bird species. Based upon several well-studied species at the time, Brown (1969, entire), summarized several frameworks for analyzing avian territoriality still prevalent in current literature. By identifying and examining the effects of territorial behavior on population density, Brown (1969) suggested that territoriality may influence reproductive rates at different population densities and in different habitats, recognizable according to their effects on patterns of dispersion. Brown (1969, pp.293-294), identified three of these density levels and emphasized that the levels need not be mutually exclusive, noting for example, that some species or populations remain at one level for several generations while other species may have populations at different or even all three levels within its known range.

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Under the three critical density levels described by Brown, the effects on reproductive rate would vary. For example, at a level 1 population density, individuals would only occupy the most productive habitats and no individual would be a non-breeding ‘floater’. In other words, individuals would not be forced out of optimal habitat into marginal habitat by aggressive competition for territories, and occupied habitats would not differ greatly in quality. Conversely, under level 3, all habitats where breeding could possibly occur would be occupied by territorial individuals, and a surplus of potential breeders would exist as non-breeding ‘floaters’. Also, under level 3, occupied habitats would significantly differ in density and productivity (Brown 1969, p. 298).

As is noted in the literature, avian territoriality is a complex behavior (Tinbergen 1957, entire; Newton 1992, entire; Askins 1987, entire; Rodenhouse et al. 1997, p. 2,025; Both and Visser 2003, pp. 326-327), and the exact effects on a given species’ reproduction or life history are difficult to measure depending upon a variety of factors including but not limited to the continuity of the species’ habitat, dispersal distances, external forces including predation, the ability of researchers to study the species, and even human impacts (Reed 1999, pp. 234, 237; Newton and Rothery 2001 p. 242; Kempenaers et al. 2001, p. 257; Sepulcre and Kokko 2005, p. 317). The various frameworks for analyzing territorial behavior are nevertheless useful for assessing a species’ ecology and current condition.

It has been established that the Tinian Monarch defends territories and the species occupies nearly all areas present on the island which contain one of the three forest habitats (Engbring et al. 1986, pp. 69-71; USFWS 1996, pp. 41-45; Lusk et al. 2000, pp. 184-186; U.S. Navy 2014, p. 2-14). It also known that the Monarch occurs at different densities within the three forest habitat types and that native forest appears to be more productive and supports higher densities than the other two forest types on Tinian (USFWS 1996, pp. 38, 40, 41, 43; Amidon et al. in litt. 2016, pp. 11-12, 15). We can therefore assume that the Monarch population on Tinian currently exists at a critical density level three as described by Brown 1969 (p. 294), which means nearly all habitat available for breeding, both optimal and marginal, is already being utilized by the species. While density alone is not always an indicator of habitat quality (Fretwell and Lucas

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1970, entire; Van Horne 1983, entire), it is a good indicator when coupled with information about reproductive success between different habitats (Van Horne 1983, entire).

Our closest indication of annual survivorship rate for the Monarch is derived from the post- delisting monitoring studies of the species conducted between 2006 and 2011. Cumulatively across the several years of monitoring, Amidon et al. (in litt. 2016, p. 12) found estimates for overall annual survival rate for color-banded birds (78% ± 0.3% SE (standard error) were nearly consistent with their observations of the annual breeding territory (nearly synonymous with home range in the case of the Monarch) turnover rate of 20% (averaged overall for three different study plots). The average annual territory turnover rate for the three study plots was 17% (n=4), 21% (n=4), and 22% (n= 2), indicating that average turnover rates at each site were similar despite variability at sites among years (Figure 10).

Figure 10. Annual territory turnover rates for the three study sites on the island of Tinian sampled from 2006–2010. The Seaport site was first sampled in 2007. However, the data for that year was not included in the analysis due to limited sampling.

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2.2.4 Home-Range Sizes

Based upon the available information, the home-range and breeding territory size for the Tinian Monarch are similar in size (avian breeding territory is generally smaller and occurs within the boundary of the home range) and are smallest within the native forest compared with the other forest types on Tinian (USFWS 1996, pp. 38, 40; Amidon et al. 2016, pp. 11-12, 15; Table 6 and Figure 11). During the 1994-1995 life history study, 84 Tinian Monarchs were captured and banded (for rates of occurrence by habitat type, see Table 6). Subsequently, 71 birds (85%) were observed again at least once in their respective original study plots. Thirty-four (40.4%) were observed 20 or more times within their respective study plots, allowing for an analysis of home-range size by habitat type (Table 6). While the average home-range size of Monarchs in the secondary-mixed forest was 20% smaller than those located within the tangantangan forest, the average home-range size of Monarchs in the native forest was four to five times smaller compared to the other two forest habitats. Tinian Monarch home-ranges were observed to overlap in all three habitat types.

Table 6. Home-range estimates by forest type for Tinian Monarch later observed at least once (from USFWS 1996, p. 38). Birds Later Birds Later Observed at Least Observed ≥20 Birds Originally Home Range Size Forest Habitat Once (count / Times (count / Captured and Type percent of percent of Banded (count) (ac / ha) originally originally captured) captured)

Native 40 36 / 90% 0.3 / 0.1 17 / 43%

Secondary- 24 18 / 75% 1.3 / 0.5 8 / 33% Mixed

Tangantangan 20 17 / 85% 1.6 / 0.6 9 / 45%

Total 84 71 / 85% 1.06 / .4 * 34 / 40%

* Average size

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Figure 11. Average Tinian Monarch territory size per year at three study plots on Tinian. The Seaport site was not monitored in 2007 and the Santa Lourdes and Airport Mitigation Area (Airport) sites were not monitored in 2011. (From Amidon et al. in litt. 2016, p. 12).

Additionally, during the 2006-2009 post delisting monitoring studies, researchers found the territory size in the Airport Mitigation Area study plot was remarkably similar to the average territory size determined for that same area during the 1994 to 1995 life history studies, which was 0.12±0.02 ha (n = 17) (Amidon et al. in litt. 2016, p. 12). This indicates that the Monarch territory size (at least in that area) apparently remained stable from 1994 to 2010 (USFWS 1996, pp. 38, 40; Amidon et al. in litt. 2016, p. 15). The territory size at the Seaport Tangantangan study plot during the post delisting study was smaller than the sizes sampled in the tangantangan (0.64±0.08 ha (n = 9) and secondary-mixed forest (0.51±0.06 ha (n = 8) sites sampled in 1995, however it fell within the range of territory sizes (0.35–0.58 ha) recorded at the two secondary- mixed forest, the two tangantangan forest, and the territory mapping plots sampled in August 2008 as part of the island-wide forest bird survey that year (Marshall and Amidon in litt. 2009, p. 6).

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2.2.5 Densities

The 1994–1995 life history study of the Tinian Monarch found density to be the highest within the native forest among study plots within the three forest types. Based upon re-sighting distance within each forest type, the density of Tinian Monarchs in the native forest (30.7 birds / ha) was four to five greater than secondary-mixed (7.7 birds /ha) or tangantangan (6 birds / ha) forest habitats (Table 7). These densities were also corroborated by the determination that home-range sizes in the native forest were four to five times smaller than observed in the two other forest habitats (USFWS 1996, pp. 40–41); Amidon et al. in litt. 2016, pp. 11-12, 15).

Table 7. Tinian Monarch densities by forest type from 1994–1995. Study Plot Estimated Estimated Study plot # Banded Estimated # of Size (ac / total # of density (birds / forest type birds un-banded birds ha) birds ha) Native 1.1 / 0.5 36 10 46 30.7 Secondary- 2.3 / 0.9 18 5 23 7.7 Mixed Tangantangan 2.6 / 1.1 17 4 21 6 Totals 6.0 / 2.4 71 19 90

Monarch densities were estimated by adding the number of unbanded and banded Monarchs. The estimate was made by establishing the average same day re-sighting distance for birds in each forest study plot: 164 ft (50 m) for the native forest, 230 ft (70 m) for the secondary-mixed forest, and 263 ft (80 m) in the tangantangan forest (Figure 12). Underlying the density analysis was the primary assumption that unbanded Monarchs in the native forest study plot seen on the same day more than these distances were distinct individuals. The proportion of banded to unbanded birds in all three study plots were fairly consistent, ranging from 71% to 74% (Figure 12).

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Figure 12. Distance between same-day re-sightings of banded Tinian Monarchs within the three forest habitat types (from USFWS 1996, p. 30). The “Limestone Forest” category refers to the native forest.

In our analysis (Amidon in litt. 2017, entire) of the potential displacement of the Tinian monarch due to impacts of projected military and civilian development, (see further discussion in section 4.3.1 below), we noted that different density estimates between forest types are possible depending upon the dataset used. For example, the preceding paragraphs describe density estimates derived from territory mapping and small scale study plot studies from the 1994-1995

49 Tinian Monarch SSA Version 1.0 life history and the 2006-2011 post delisting monitoring studies. However, Tinian monarch density has also been calculated using datasets from the island-wide forest bird point-transect surveys (Engbring et al. 1986; Lusk et al. 2000; Amidon and Marshall 2010; NAVFAC 2014), described below in section 3.1.2.2.

The Service analyzed the results of all the aforementioned studies and surveys and determined that potentially large differences in Tinian Monarch density are indicated between forest types when using data from the territory mapping and small scale study plot studies (Amidon in litt. 2017, p. 5). Conversely, datasets from the four point-transect surveys produced similar estimates for each forest type. These differences in density estimates are, in part, due to the birds that were sampled using each method and the methods sampling breadth or extent. The territory mapping studies focused on territorial males and females, while the four point-transect surveys, in theory, could sample all territory and non-territory holding Tinian Monarchs (e.g., adult and juvenile males and females) (Amidon in litt. 2017, p. 5).

Additionally, it is important to note that the four island-wide point-transect surveys sampled habitats surrounding a survey station which may have include multiple forest types due to the patchy distribution of forests on Tinian. The type of habitat at a given station may have resulted in a lower or higher estimate depending on the amount of each forest type at each station and the preference for each forest type by the Tinian Monarch. Because the territory mapping studies focused on plots composed of one forest type, they likely better represent actual density in that forest type (Amidon in litt. 2017, p. 5). However, the caveat with using data from the territory mapping studies to calculate density is that they included a small number of plots and thus may not be representative of density in all areas with those forest types. To account for the density estimate variability in the datasets, we evaluated each in our assessment of potential Monarch displacement (described in section 3.1.2.2), and found that differences between estimates from the different datasets were not statistically significant (Table 8).

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Table 8. Tinian Monarch density estimates derived from point-transect sampling and territory mapping studies on the island of Tinian. (Territory mapping density estimates were multiplied by two to estimate the number of birds per hectare. Point-transect estimates for Camp et al. 2012 and NAVFAC 2014 are not directly comparable due to differences in data used to derive detection functions. However, all density estimates within NAVFAC 2014 are comparable. Transect analyzed indicates which survey transects were used to derive the density estimates.) Density Estimate (birds / hectare) Sampling Transects Survey Native Mixed- Study Tangantangan Method Analyzed Period Limestone secondary Forest Forest Forest 1994- USFWS 1996 NA* 16.38 3.13 3.90 1995 Territory USFWS 2008 NA* 2008 15.28 4.31 5.27 Mapping 2005- USFWS 2017 NA* 16.21 5.04 NA 2010 Camp et al. 1-14 2008 6.62 3.99 5.5 2012 Point- NAVFAC transect 1-10 2008 7.36 6.83 9.51 2014 (island- NAVFAC wide 1-14 2013 11.19 10.15 11.01 2014 surveys) NAVFAC 1-10 2013 11.05 10.12 10.9 2014 *These studies sampled small-scale study plots

2.3 Population / Species Needs

In the previous section, we discussed the individual needs of the Tinian Monarch. Here, we assess the Monarch’s needs as a population and a species using the concepts of the 3R’s (resiliency, representation, and redundancy, as summarized in Table 9). The Tinian Monarch is endemic to Tinian, which is the historical limit of its range and where it is considered a single population. We discuss the needs of the Tinian Monarch at the population- and species-levels together, because the species is comprised of a single population on Tinian. As noted in Chapter

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1, the translocation project on Guguan is still in its nascent stages and the success of a stable, reproducing population cannot be determined at this time; we therefore, do not consider the Monarchs on Guguan in this assessment of the species’ resiliency and viability.

2.3.1 Resiliency

The Tinian Monarch is comprised of a single population exhibiting demographic patterns characterized by rebounding from periods of dramatic habitat and population change. Thus, the resiliency - or ability of the species to withstand stochastic events - is primarily tied to the size and distribution of its population across the island of Tinian and an evidently high intrinsic growth rate. The availability of forest habitat of sufficient area and continuity, which the species requires, as well as the absence of certain invasive predators (i.e., the brown treesnake), greatly shape the Monarch’s population size, distribution, and overall resiliency as we discuss in greater detail in the following sections and chapters of this analysis.

Although we have somewhat limited information regarding Monarch population demographics, we do have information on several components of its biology, including density, home range / territory size, and breeding success in the three forest habitat types over consistent periods of time. The amount of forest habitat varies according to forest type inhabited, and thus, the Monarch’s current distribution is based upon the present distribution of forest cover on Tinian (USFWS 1996 entire; Lusk et al. 2000, pp. 186–187; USFWS in litt. 2016, p. 2). Additionally, past survey results indicate that an increase in Monarch population apparently followed an increase in forest cover over time (Lusk et al. 2000, pp. 186-187). Therefore, we believe the Monarch’s resiliency is directly tied to the amount and connectivity of forest habitat on Tinian.

The 1994-1995 life history studies and post-delisting monitoring studies (USFWS 1996, entire; Amidon et al. in litt. 2016, p. 5) indicated that native forest supports higher densities of Tinian Monarchs and likely higher breeding success compared to secondary-mixed or tangantangan forests. Thus, we believe retaining native forest is important in maintaining the Monarch’s resiliency.

Because Monarchs require a territory to breed, when a Monarch’s territory is permanently lost (e.g. from habitat removal), the result is a reduction in reproductive success, but not necessarily

52 Tinian Monarch SSA Version 1.0 mortality, as Monarchs can exists as ‘floaters’ (i.e. non-breeding individuals) in other areas of suitable habitat. However, given the territorial nature of the species, floaters may not readily establish another territory overlapping with an existing territory. Therefore, the result of habitat loss can be an overall decline in species abundance due to a reduction in reproductive success. Moreover, because a reduction in reproductive success could take at least one generation to have an impact on the species’ overall abundance, the impact to species abundance may be observed over a period of time extending beyond an event that caused habitat loss. We describe a Monarch that has lost its territory as being “displaced.”

As noted above regarding displacement, we expect that any complete loss of forest habitat within a particular area, regardless of cause, would displace Monarchs from that area (Brown 1969, entire; U.S. Navy 2015, pp. 4-200, 4-221; Amidon in litt. 2017, entire), perhaps indefinitely. Furthermore, we believe Monarch displacement due to forest habitat loss would lead to a reduction in reproductive success and therefore an overall reduction in the island-wide Monarch abundance over time, possibly within two to three breeding seasons. This assessment is based upon the Monarch being moderately territorial (Engbring et al. 1986, p. 69; USFWS 1996, p. 34; U.S. Navy 2015, pp. 4-200, 4-221; Amidon et al. in litt. 2016, pp. 5, 11-12) and unlikely to tolerate rivals within smaller habitat patches when densities increase due to adjacent or nearby habitat loss or destruction.

Forest habitat also provides shelter and protection from storms and fulfills breeding needs as well as feeding needs through insect populations, all of which depends upon rainfall (USFWS 1996, pp. 28, 35, 37, 44; Amidon et al. 2016 in litt., p. 2). In Chapter 4, “Factors Influencing Viability” we discuss risks to the forest habitat on Tinian, including loss and degradation of forest habitat, typhoons and drought. The Tinian Monarch as a species, also needs forest habitat that is relatively free of predators such as rats, cats, and monitor lizards, and entirely absent of non- native predators such as the brown treesnake. As discussed in Section 4.5.6 “Predation,” there is little evidence that the Monarch is currently being preyed upon by such predators. And in Section 4.2 “Brown treesnake (BTS)” we discuss the risk posed by the non-native predator, particularly in light of the havoc it has wreaked on Guam.

2.3.2 Representation and Redundancy

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The Tinian Monarch is represented by a single population with little to no discontinuity among individuals from geographic or other barriers. Although we lack specific knowledge of the Monarch’s genetics, we expect that its capacity to adapt to future environmental change is limited to the adaptive capacity currently within the single island population, which can be productive in a diversity of forest types. Tinian Monarchs are currently linked to one another across the island by a nearly contiguous patchwork of forest cover. Given military and civilian development projections for the island, we expect that maintaining continuity among localized concentrations of the species could at some point in the future require elements of protection and active management.

Finally, redundancy is a function of the scale of catastrophic events relative to the spatial distribution of multiple populations or spatial extent of a single population. We consider the possibility of BTS becoming established on Tinian to be the catastrophic event of greatest concern for Tinian Monarch. To maintain localized Monarch population densities and sustain the species, forest habitat must be relatively free of high densities of predators in general and entirely devoid of non-native predators such as the BTS. The limited distribution leaves the Monarch particularly vulnerable to invasion by the BTS.

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Table 9. The 3Rs analysis for examining Tinian Monarch viability. 3Rs Definition Application to the Tinian Monarch The Monarch’s single Tinian population must span the island at least Large, robust at current densities to withstand the effects of periodic or gradual populations able to loss or both or degradation of habitat from development, drought, withstand periodic typhoons, the effects of feral ungulates and non-native plants, and Resiliency and localized human activities, including those that result in wildfire. It must also disturbance from be robust to overcome the effects of potential disease outbreaks and stochastic events predation pressure from rodents, including the currently high population densities of rats on Tinian. Number and Redundancy for the Monarch’s single Tinian population is distribution of determined by the spatial distribution throughout the island relative populations to spread to the extent of possible catastrophic events. Redundancy risk of extirpation Therefore, the population is very vulnerable to the catastrophic due to catastrophic event of BTS establishment on Tinian because of the potential for events BTS to spread throughout the island including all Monarch habitats. While we lack information regarding the Monarch’s genetics, it is reasonable to assume that the Monarch experienced a genetic bottleneck during the large contraction of its habitat which ended in Genetic and the 1940s. In addition, because we are unaware of any biological or ecological diversity geographic barriers precluding Monarch gene flow on Tinian, we Representation to maintain adaptive believe the species is comprised of one interbreeding population. potential The Monarch is apparently a generalist, capable of feeding and nesting within three different forest types on Tinian, and we do not believe individuals in different habitat types represent genetically distinct groups with any appreciable variation in adaptive capacity.

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Chapter Three: Current Condition

In this chapter, we provide an overview of the Tinian Monarch’s current condition, including the species distribution and abundance across the island and the studies from which this information was gathered.

3.1 Tinian Monarch Distribution and Abundance

3.1.1 From 1945–1976

Prior to the first detailed forest bird survey on Tinian, several early accounts from the 1940s and again in the 1970s indicate that the Tinian Monarch was widely distributed across the island within forest habitats, and by the 1970s, in high numbers. It was only near the end of WWII, that the first account of the Tinian Monarch’s status and distribution on Tinian was recorded. In June of 1945, D.A. Gleize, a U.S. soldier and amateur ornithologist stationed on the island, recorded observations of 18 bird species, including 40–50 observed Monarchs. Theodore Downs, an Army Air Force soldier stationed on Tinian between June and October, 1946, published the article “Birds on Tinian in the Marianas” regarding his four-month tour of duty on Tinian, during which he recorded 15 species of birds including the Tinian Monarch.

Down’s article includes the first detailed notes (Downs 1946, pp. 100–103) about the species’ biology and our first recorded distribution of the species, pictured on a hand-drawn map (Downs 1946, p. 188; Figure 13). Downs noted that his ability to survey Tinian was limited because of booby traps and remaining Japanese snipers (Downs 1946, p. 90); therefore his recorded observations, while helpful, cannot be considered systematic or an accurate assessment of the Monarch’s distribution.

Downs (1946, pg. 87) is clear that he observed Monarchs at five of eleven sites surveyed (Figure 13), with the number of recorded individuals varying between one and four birds. However, Downs’ article is unclear whether the Monarch was observed at these five locations once each or on more than one occasion. Based upon his map, we discern that Downs found the Monarch to occupy approximately 50% of the eleven forest sites surveyed under limiting circumstances on

56 Tinian Monarch SSA Version 1.0 the island during his four month visit, with birds observed at three sites in the north and at two sites in the south.

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Figure 13. Hand-drawn map by Theodore Downs (1946, p. 90) showing locations of recorded bird observations between June and October of 1946. Tinian Monarch sites of observation are indicated by red circles.

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The second historical account of the Monarch was provided by Joe Marshall, who surveyed Tinian, Saipan, and Guam for the U.S. Army between December 1944 and December 1945 to collect ectoparasites and other animals of medical importance. In the course of obtaining parasites from birds, Marshall recorded his field observations and notes on collected species, publishing the 1949 article, “The Endemic Avifauna of Saipan, Tinian, Guam, and Palau” (Figure 14). In his article, Marshall devoted approximately one page on the Monarch, writing, “The Tinian Monarch ... is present in about equal numbers with Rhipidura [rufous fantails] in woodland, but it reaches the peak of its abundance in a kind of arborescent marsh vegetation found in Marpo Valley” (Marshall 1949, p. 214).

Marshall also noted that with the exception of the bridled white eye within planted acacia trees on Tinian, all observed native birds were “either confined to [their] natural environment or achieve their maximum abundance in it.” Perhaps implying that he thought it was sufficiently abundant to do so, Marshall also shot and collected 35 Tinian Monarchs during the course of his survey.

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Figure 14. From Marshall 1949, p. 205: “View of part of largest area of undisturbed forest (right center) on Tinian.”

During the summer of 1976, three ornithologists visited Tinian for four days as part of a larger project to record observations of bird species in the Mariana Islands including Guam. Based upon their field visits and recent field notes from other ornithologists, Pratt et al. published the article, “America's unknown avifauna: the birds of the Mariana Islands” in 1979 in American Birds. Pratt et al. 1979 was notable for not only describing the Monarch’s abundance on Tinian after a 30-year absence of information but also for officially detailing the possible misinterpretation of Gleize’s 1945 article by the ICUN that lead to the species’ Federal listing in 1969.

Regarding the Tinian Monarch’s abundance and distribution, Pratt et al. (1979 p. 231), stated that all of the authors found the species to be abundant in their visits in 1974, 1975, and again in 1976. Pratt et al. (1979, p. 231) suggested the Tinian Monarch’s population “must surely number in the

60 Tinian Monarch SSA Version 1.0 tens of thousands,” and identified the species as “the most conspicuous bird on Tinian” during their 1976 visit.

3.1.2 From 1982–2013

Several bird studies have been conducted on Tinian to determine the abundance and distribution of its bird populations, and are summarized in Table 10, below.

Table 10. Summary of Tinian Monarch studies that inform our understanding of the species' abundance and distribution. Survey Year Type of Study Methodology Agency / Citation Name Island-wide island-wide forest USFWS, funded by the population / forest bird 1982 bird point-transect Department of the Interior / distribution surveys surveys Engbring et al. 1986 island-wide forest USFWS, funded by the population / 1996 bird point-transect U.S. Navy / distribution surveys Lusk et al. 2000 island-wide forest USFWS, funded by the population / 2008 bird point-transect U.S. Navy / distribution surveys USFWS 2009 island-wide forest Independent contractor, population / 2013 bird point-transect funded by the U.S. Navy / distribution surveys U.S. Navy 2014 BBS 16 quarterly roadside initially the U.S. Navy, Roadside 1999– counts, also known later taken over by CNMI distribution counts* 2010 as breeding bird DFW / surveys Amidon et al. in litt. 2016 *The BBS roadside counts are actually ongoing by the DFW. Our analysis only examined the 16 surveys conducted between 1999 and 2010.

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3.1.2.2 Island-wide forest bird surveys Comprehensive, island-wide forest bird surveys using point-transect methodology have been conducted on Tinian on a total of four occasions: in 1982, 1996, 2008, and in 2013 (Engbring et al. 1986; Lusk et al. 2000; Amidon and Marshall 2010; NAVFAC 2014, respectively; Table 11). The population abundance, distribution, and density data discussed in this section are derived from these four surveys, all of which used the same methodology and the same transects. Evenly spaced point-transect areas were selected by researchers based on habitat types, and largely excluded those habitats not inhabited by the Monarch, such as urban and cultivated lands (Engbring et al. 1982, p. 23; Figure 15). Individual birds heard and seen were recorded on counts that lasted eight minutes, and results were extrapolated to determine population and density (Engbring et al. 1982, p. 24).

With each additional survey, more data on the Tinian Monarch population were collected, and the methods used to analyze the datasets and estimate the population abundance and density were improved (Camp in litt. 2016; Amidon in litt. 2017). Following the most recent survey in 2013, researchers in 2014 reanalyzed data from all four surveys to estimate the 2013 population abundance and density of the Monarch (NAVFAC 2014, pp. 2-11; Table 11). With the improved data and methodology, the 2014 reanalysis also resulted in revised estimates of past population abundance and density. In general, reanalysis of the older survey data lead to increases in estimated density and abundance for the Monarch for all three years. When considering standard deviation for all four surveys, the reanalysis suggests that the Monarch population has been relatively stable (NAVFAC 2014, pp. 2-11; Table 11).

In this report, we have provided both the 2014 reanalyzed population estimates for all surveys, as well as the original survey population estimates because some of the prior listing actions for the Monarch were informed and based upon those estimates at their respective dates in time. For example, the monarch was delisted in 2004, largely due to an apparent increase in abundance between the 1982 and 1996 surveys. However, researchers consider the best available population estimates to be those produced most recently from the 2014 reanalysis (Camp in litt. 2016; Amidon in litt. 2017). As noted above, the 2014 reanalysis did not reverse of prior estimates abundance, but did indicate that Monarch abundance has been much higher all along than previously estimated. Therefore, throughout our discussion of the Tinian Monarch’s past

62 Tinian Monarch SSA Version 1.0 and present population abundance, we will refer to the 2014 reanalyzed estimates of abundance rather than the original estimates.

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Figure 15. Map of Tinian showing transects from all four (1982, 1996, 2008, 2013) island-wide forest bird surveys.

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Table 11. Tinian Monarch surveys, summary of initial and reanalyzed findings. Island-wide Analysis of Survey Results Forest Bird 1982 Analysis of Survey Results 1996 Analysis of All Survey Results 2008 Analysis of All Survey Results 2013 Analysis of All Survey Results (point-transect) Abundance Density Abundance Density Abundance Density Abundance Density Survey (total population) (birds / ha) (total population) (birds / ha) (total population) (birds / ha) (total population) (birds / ha)

1982 Forest 35,846 ± 2,211 60,898 634.5 ± 37.88 95,916 9.806 ± 1.023 39,338 541* 5.71 Bird Survey (a) (31,668–40,337) (49,484–75,398) (564.3–713.4) (77,491−116,202) (7.923−11.880)

1996 Forest 55,721 ± 3,846 62,863 705.7 ± 43.96 105,352 10.771 ± 1.138 8.85 Bird Survey (b) (48,345–63,495) (50,476–78,758) (624.3–797.6) (84,237−127,758) (8.612−13.062)

2008 Forest 38,449 431.3 ± 30.75 56,305 5.757 ± 0.705

Bird Survey (c) (29,992–49,849) (374.9–496.2) (43,343−70,909) (4.431−7.249)

2013 Forest 90,634 9.266 ± 1.121

Bird Survey (d) (69,311−112,535) (7.086−11.505) NOTE: Figures in bold indicate initial findings. Figures in italics indicate reanalyzed findings. Shaded boxes indicate numbers that have been reanalyzed and are no longer relevant. Abundance is calculated using (birds / ha ± SE). Density is calculated using (birds / ha ± SE). Both abundance and density are at a 95% CI. SE was not reported 2008 and 2013 for abundance. *initially reported as a raw number (541). For purposes of comparison, converted to density per hectare. Sources of data: (a) Engbring, J., F.L. Ramsey, and V.J. Wildman. (1982). Micronesian Forest Bird Survey 1986: Saipan, Tinian, Agiguan, and Rota. p. 43–44. (b) Lusk, M., S. Hess, M. Reynolds, and S. Johnston. (2000). Population status of the Tinian Monarch (Monarcha takatsukasae) on Tinian, Commonwealth of the Northern Mariana Islands. Micronesica. 32.2: 181– 190. p. 181. (c) USFWS. (2009). Terrestrial Resource Surveys of Tinian and Aguiguan, Mariana Islands, 2008 - Final Report. Pp. 227-239. (d) NAVFAC. (July 2014). Final Survey Report. “Terrestrial Biological Surveys on Tinian in Support of the Commonwealth of the Northern Mariana Islands Joint Military Training Environmental Impact Statement / Overseas Environmental Impact Statement.” p. 2-11 (21).

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During the first island-wide forest bird survey conducted in May 1982, the Service found the Tinian Monarch to be the second most abundant bird on the island and estimated the population

at 39,338 ± 2,131 SE birds (reanalyzed in 2013 at 95, 916 birds) widely distributed over the island in all forest types, absent only from un-vegetated areas, open fields, and agricultural areas (Engbring et al. 1986, p. 69-71; NAVFAC, 2014, p. 21). The Service relied upon data from this study when it made the determination to downlist the Tinian Monarch from an endangered to a threatened species in 1987 (USFWS 1987).

Results from the second island-wide forest bird survey, conducted in August 1996, estimated the Tinian Monarch population at 55,721 birds (reanalyzed in 2013 at 105,352 birds) (Lusk et al. 2000, p. 186; NAVFAC, 2014, p. 21). Notably, the study also found that vegetation density had increased in all forest types as well as some increase in forest cover since 1982, leading Lusk et al. (p. 186) to hypothesize that observed increases in Monarch abundance and density were most likely due to documented increases in density of vegetation based on accounts obtained from biologists and botanists familiar with the habitats of Tinian (C. Aguon, T. Sutterfield, pers. comm., as quoted in Lusk et al. (p. 187)).

Lusk et al. (p. 187) also noted that when the initial bird survey was completed in 1982, there were approximately 6,000 to 7,000 cattle on Tinian, with cattle numbers falling to approximately 4,000 by 1993 and to approximately 2,000 by 1996 due to a series of droughts (Micronesian Development Company, pers. comm., as quoted in Lusk et al. 2000, p. 187). Lusk et al. (2000, p. 187) hypothesized that the large reduction in cattle grazing likely resulted in regeneration of the understory growth and increased seedling recruitment, leading to higher quality Monarch habitat on many parts of the island. Based on the 1996 data that Tinian Monarch numbers had increased or were at least stable; that the primary threat to the species, loss of forest habitat, had been ameliorated; and that the species was not currently threatened by other factors, the Tinian Monarch was subsequently delisted in 2004 (USFWS 2004).

The third island-wide forest bird survey was conducted in June 2008 and estimated the Tinian Monarch population at approximately 38,000 birds (reanalyzed in 2013 at 56,305 birds), a large decrease from the 1996 survey estimate of 55,305 birds (or the 2008 reanalysis of 49,047 birds), but still a wide distribution over the island in all forest types (USFWS, 2009, p. 227; NAVFAC

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2014, p. 21). The cause of this reported drop in population size in unclear. Weather conditions including cloud cover, rain, wind strength, etc., were similar between surveys, which suggests the detectability of Monarchs during surveys were consistent. However, variation in estimated population size among years can be caused by 1) true changes in population size or 2) or possibly, by errors associated with imperfect sampling and modeling of the population (Camp in litt. 2016).

Unfortunately, separating these two sources of variation in population estimates between years is not possible without a more regular and continuous series of surveys over time, ideally annually. However, we did investigate whether some biologically meaningful factors may have caused the drop in the Tinian Monarch population, including, but not limited to, changes in rainfall and other weather conditions, an avian pox incidence, and fluctuation in insect prey availability. Rainfall was reported generally higher in the five years preceding the 2008 survey (Amidon pers. comm. 2017), which may have caused an increase in pox-carrying mosquitos and infected Monarchs (see section 4.5.7 “Avian pox”). However, other than some observations of Monarchs with pox lesions during this same time period, we lack other data to corroborate this theory including data regarding mosquito populations on Tinian.

Additionally, while weather phenomena or reduced insect prey abundance could potentially have caused a decrease in the Monarch’s population, we have no data indicating either a weather phenomenon or decrease in prey abundance occurred that could cause such an impact during that time. Indeed, the aforementioned period of higher rainfall preceding the 2008 decline would likely have increased insect prey. The strongest evidence against a habitat-caused explanation for the observed decline in Monarchs in 2008 was the concurrent observed increase during the same survey of the rufous fantail, also an insectivorous, forest dwelling bird species (USFWS 2009, pp. 153, 158, 236).

In June of 2013, a fourth island-wide forest bird survey was funded by the U.S. Navy and conducted by U.S. Navy contractors, unlike the first three surveys which were conducted by Service biologists. Results of the survey indicated that the Tinian Monarch population had largely rebounded from the apparent decline observed in the 2008 surveys (estimated in 2008 at 38,449 bird and reanalyzed in 2013 at 56,305 birds) to a new population estimate of

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approximately 90,634 birds (NAVFAC 2014, p. 2-11 (21)). The U.S. Navy’s report of these surveys also included the reanalysis of previous survey estimates, as discussed above.

Overall, despite an unexplained and nearly 50% drop in the estimated population size between 1996 and 2008, the general trend in Monarch abundance and density appears stable since 1982 with the most recent survey in 2013 estimating a population of 90,634 birds. Additionally, in conjunction with the other studies of the species (see section 3.2.2.4 “Post-delisting monitoring”), results from these transect surveys, indicate the Monarch maintains a wide distribution across the island.

3.1.2.3 Quarterly roadside survey counts As briefly described in section 2.2 above, quarterly breeding bird surveys were begun in 1999 as roadside counts and conducted at sites around the island. The counts were initiated by the U.S. Navy, in part, to demonstrate that delisting may be warranted (Figure 6, above in section 2.2 “Life Cycle and Individual Needs”). The 1999-2010 results from the study were analyzed as part of the post-delisting monitoring studies (see section 2.2 “Life Cycle and Individual Needs”), since they coincided with the timeframe although they began five years before the species was delisted in 2004. The studies were intended to be quarterly, but lack of funding and personnel led to data gaps from 2001–2003 and from 2006–2009.

In all, 16 quarterly roadside counts were completed from 1999–2010. During these roadside survey counts, trained observers recorded detections of all birds seen or heard within an unlimited distance from the (roadside) station during a three minute period at each station in the months of January, April, July and October annually. Average detection per station was similar across most of the surveys (range: 0.5–0.8) (Amidon et al. in litt. 2016, p. 8). The notable exceptions were the November 1999, January 2001, April 2003, and July 2003 survey, during which detections per station were all greater than one, possibly due to extra observers during three of those four dates (Amidon et al. in litt. 2016, p. 8). The study noted that if the four outlier surveys were dropped from the data set, a clear stable trend becomes apparent across the survey period based on the 95% confidence intervals of each estimate (Figure 16).

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Figure 16. Average Tinian Monarch detections by bird per station (95% CI) during quarterly surveys conducted from 1999–2010. The X-axis shows mean annual bird detections per survey station. Dates are numerical month (e.g., April = 4) and year (from Amidon et al. in litt. 2016, p. 8).

Since 2010, DFW biologists have continued the quarterly roadside counts (with occasional surveys missed) using Pittman-Robertson funding (Liske pers comm. 2018). Basic results from the surveys are summarized below in Table 12 and Figure 17.

Table 12. Breeding bird survey roadside count cumulative summary statistics for the Tinian Monarch and Rufous fantail (for comparison), 1999 – 2017 (adapted from DFW in litt. 2017). Total Relative Species Occurrence SD SE Observed Abundance Rufous fantail 2,411 72.9 2.052 1.612 .045 Tinian Monarch 1,311 48.4 1.116 1.69 .047 Occurrence was calculated as the number of stations or counts with one or more individuals divided by the total number of stations or counts x 100%. Relative abundance was calculated as the total number of on-count detections divided by the number of stations or counts. Occurrence and relative abundance are based upon n = 1,275 counts across all stations between Nov 1999 and July 2017.

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Figure 17. Mean annual Tinian Monarch detections per survey station from 1999-2017.

3.1.3 Summary

Overall, despite an unexplained and substantial (nearly 50%) drop in the estimated population size between 1996 and 2008, the general trend in Monarch abundance and density appears stable since 1982 with the most recent survey in 2013 estimating a population of 90,634 birds. Additionally, results from island-wide forest bird surveys and roadside surveys, indicate the Monarch maintains a wide distribution across the island.

3.2 Factors Influencing Current Viability

This chapter reviews historical and present factors influencing Tinian Monarch viability. Historically and presently, the most important factor influencing the Monarch’s current viability is forest habitat loss due to human activities. In this section, we review past and ongoing changes to forest habitat and its overall impact to the species. In addition, we explore numerous other factors that could have an impact on either the availability of forest habitat or on Monarchs directly. These factors include, but are not limited to: effects of climate change, such as typhoons and drought, cattle ranching, feral goat activity, the cumulative effects of increasing

70 Tinian Monarch SSA Version 1.0 abundance and distribution of invasive, non-native plants, predation from rats, cats, and monitor lizards, and avian pox. We explore the impacts of these other factors and activities because they may occur on Tinian and have often been identified in the literature as possible stressors to the Monarch. However, we lack sufficient, measurable evidence to show that they are individually or collectively impacting the species. Other extremely important factors that may influence the viability of the Monarch in the future include habitat loss and degradation due to development and the potential introduction of BTS. These factors are addressed in Chapter Five “Future Condition”.

3.2.1 Forest Habitat Changes Due to Human Activity over Time

Beginning with the settlement of the Chamorro people on the island 3,000-4,000 years ago, human activities have historically and drastically altered Tinian’s landscape including the composition and amount of forest habitat. As the Chamorro civilization grew into a relatively complex and well-populated society, Tinian’s forest habitat and ecology were impacted by clearing, fires, and likely, the first introductions of non-native species (Butler 1992, pp. 12-13, 21-23). The arrival of Europeans to the Marianas in the 1500s brought additional impacts to the island’s ecosystem, particularly with the introduction of goats, cattle, and pigs as well as further clearing of forest habitat (Butler 1992, pp. 14-15). In the early 1700s until the end of WWII, human activities continued to seriously reduce what was originally native forest habitat to small remnants (Fosberg 1960, p. 46-47).

Impacts to Tinian’s forests accelerated particularly throughout the 1920s during which “the Japanese cleared every square foot [of Tinian] that was level and had soil” for sugarcane production (Fosberg 1960, p. 47; Berger et al. 2005, pp. 36–37; Figure 18). Damaging and suppressive impacts to Tinian’s native vegetation continued as a result of Japanese and U.S. military activities during WWII (Mueller-Dombois and Fosberg 1998, p. 262; Russell 1998, p. 98; CNMI-SWARS 2010, pp. 6−7, 28−29). During the war, many areas on the island either were cleared for construction of military facilities or were affected by battles between U.S. and Japanese forces (Baker 1946, p. 206; Downs 1946, p. 89; Falanruw et al. 1989, p. 8). After 1944, the U.S. military took control of Tinian for the remainder of the war against Japan and converted large portions of the island into a major airbase, the busiest in the world at that time (Camp et al.

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2012, p. 284; Figure 19). Immediately following WWII, remaining forest habitat was estimated at only 2% of the island cover (Bowers 1950, p. 206), and subsequently, the island was largely abandoned by the military for many years.

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Figure 18. Map of Tinian showing the extent of sugar cane cultivation (32.8 square miles) during the Japanese period of colonization on the island (Map from The Seizure of Tinian. USMC Historical Monograph).

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Following the end of WWII, the overall trend in changes to forest habitat on Tinian has been a documented steady and substantial increase in total forest cover through the 1990s (Lusk et al. 2000, p. 181), although its composition has greatly changed. In conjunction with the overall increase in forest cover on Tinian over time, human activities have periodically caused fluctuations in the total amount of forest habitat cover and have likely contributed to a steady shift toward greater numbers and abundances of nonnative plants within a large matrix of mostly mixed-secondary and tangantangan forest. These human activities included the ebb and flow of the ranching industry over time, periodic construction and development, for example the Voice of America antenna facility, North Field runway clearing for military activities, the initial modern airport, its expansion, and civilian development in southern Tinian including the Dynasty casino. Currently, only occasional construction projects in southern Tinian and the existing ranching industry are impacting the amount of forest habitat available to the Monarch.

Regarding forest composition, the majority of the island was likely once covered in native forest, however only about 5% of the native forest currently remains on Tinian (5% of the island’s land cover is native forest) (Fosberg 1960, pp. 46-48; Engbring et al. 1986, p. 25; Falanruw et al. 1989, pp. 2, 7-8; Liu and Fischer 2006, entire). Native forest patches are now found only along cliff lines and limestone escarpments around the several plateaus on the southeast side of Tinian and in a narrow corridor on the limestone escarpment that connects Mt. Lasu with the Maga clifflines (Falanruw et al. 1989, p. 8; Liu and Fischer 2006, entire; U.S. Navy 2015, p. 3-113). It is likely the ruggedness of the karst limestone features and escarpments precluded the development of the remaining native forest prior to and during WWII, as it does today.

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Figure 19. Photograph of the northern third of Tinian looking eastward, showing the massive runway system and the extent of the altered landscape of the Airforce’s North Field during WWII, at the time the largest airport in the world and an area of strategic military significance for the U.S. Lake Hagoi, Tinian’s only body of water, is seen in the foreground.

In 1983, the U.S. Government signed a lease with the government of the CNMI to use lands on Tinian for Department of Defense (DOD) purposes, signaling a renewed interest in the island since the end of WWII. This area is known as the Military Lease Area (MLA) and measures 15,148 ac (6,130 ha), or approximately 60.2% of the island and containing approximately 66% of all Tinian Monarch habitat (Figure 20). The MLA lease was signed for an initial term of 50 years, currently set to expire in 2033, with the option to renew the lease for additional 50 years (2033–2083). The MLA is divided into two sections roughly equal in size: 7,574 ac (3.065 ha) on the northern third of Tinian in the Exclusive Military Use Area (EMUA) and 7,779 ac (3,148

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ha) on the middle third of Tinian in what is termed the Leaseback Area (LBA) (U.S. Navy 2010, pp. 2–4).

Presently, activities in these two areas consist of airfield training in the EMUA and small-scale ground element training in the LBA (U.S. Navy 2010, 3: 2–4). Additionally, under the proposed Mariana Islands Training and Testing Area (MITT) program, DOD activities within the MLA would increasingly include training for amphibious warfare, urban warfare, personnel insertion / extraction activities, and humanitarian relief exercises (USFWS MITT Biological Opinion (BO) 2015, p. 4). Portions of the LBA are also leased to Tinian residents for commercial uses, such as ranching and other activities. Additionally, much of both the LBA and the EMUA are open to the public during the majority of the year for recreation, cultural practices, or other uses. According to U.S. Navy estimates, the MLA includes approximately 29% of the native forest on Tinian, 67% of the secondary-mixed forest, 71% of the tangantangan forest, and 66% of the total forest cover found on the island (Table 13). According to habitat density estimates from prior studies, the MLA supports approximately 52% of the Tinian Monarch population (U.S. Navy 2015, p. 3- 119).

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Figure 20. Map of Tinian showing land owner ship and military lease areas (from the CJMT (CNMI Joint Military Training) DEIS (Draft Environmental Impact Statement), U.S. Navy 2015, p. 3-83).

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Table 13. Percent of each forest type and of the Tinian Monarch population found within and outside of the Military Lease Area (MLA). Inside the Outside the MLA (ac / ha Total MLA (%)) Forest Type Total Area (ac / % of Forest

ha) Cover on Tinian

Native Forest 389 / 158 (29%) 966 / 391 (71%) 1,355 / 549 8.0%

4,689 / 1.898 2,315 / 937 Secondary-Mixed Forest 7,004 / 2,835 41.5% (67%) (33%)

6,032 / 2,441 2,499 / 1,011 Tangantangan Forest 8,531 / 3,452 50.5% (71%) (29%)

11, 149 / 4,512 5,743 / 2,324 Total Forest Cover 16,892 / 6,836 100% (66%) (34%)

Tinian Monarch 52% 48% 100% Population

In 1998, the CNMI and the Federal Aviation Administration (FAA) proposed an expansion to the Tinian Airport to accommodate larger aircraft and an expected increase in foreign travelers due to the passing of the Tinian Casino Gaming Control Act of 1989 (USFWS 1998, p. 3). The expansion required construction on an additional 605 ac (263 ha) of land, which involved clearing 405 ac (164 ha) of tangantangan and secondary-mixed forest (USFWS 1998, p. 3, 5). Consequently, the project was estimated to permanently remove breeding territories and habitat for approximately 1,100 Monarchs, resulting in reduced reproduction and an overall decline in species abundance on the island. Although the Tinian Monarch was listed as a threatened species under the Endangered Species Act at the time of the proposed airport expansion, the Service had recently recommended a reassessment of its status (USFWS 1998, p. 7), based upon the results of the 1996 survey for the species. Because of an apparent increase in the Monarch’s population since the 1982 survey and a concurrent increase in vegetation observed during the same time period (USFWS 1998, p. 9), the Service at that time did not consider the project to be a serious threat to the Monarch population, and project construction subsequently began in 1999.

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In 2004, to compensate for the loss of forest due to the expansion of the Tinian Airport, the U.S. Navy and the FAA designated 937 ac (379 ha) within the LBA as conservation lands for the Tinian monarch and several other species under mitigation agreement number 1-2-98-F-07 between the Federal Aviation Administration and the U.S. Fish and Wildlife Service, dated January 4, 1999 (USFWS 1998, entire; US Navy 2010, p. 10-4; US Navy 2015, p. 3-89). This area, called the FAA Mitigation Conservation Area (also known as the Tinian Military Retention Land for Wildlife Conservation), includes approximately 591 ac of forest, including 65 ac (23 ha) of native forest, 467 ac (189 ha) of secondary-mixed forest, and 59 ac (24 ha) of tangantangan forest (U.S. Navy 2015, p. 13). We are unaware of any management actions taking place to date since the area was designated in 2004.

In summary, the amount of forest on Tinian likely influences the abundance and distribution of the Tinian Monarch. However, despite extensive impacts to Tinian’s forest and ecosystem over thousands of years, the Tinian Monarch is currently thriving. The highly resilient nature of the Monarch is evidenced by: its rebound to an estimated population of 100,000 individuals following the extensive reduction of its habitat to less than 5% of island cover by the end of WWII; and by the species’ ability to forage and reproduce both within the small amount of remaining native forest on Tinian as well as within the non-native forest that now comprises the majority of the island’s forest cover and composition.

3.2.2 Wildfire

Forest habitat on Tinian is at risk of loss or degradation from wildfire as a result of civilian currently, and potentially from military activities and the effects of climate change in the form of either drought or typhoons. Risks from wildlife can include direct loss of Monarchs and nests, as well as indirect impacts including degradation over time. Forest habitat, particularly native forest, could also be impacted, resulting in the Monarch’s temporary or permanent displacement. Wildfires may also allow for growth of non-native species, which can cause further degradation of all forest habitat types (Bowers 1950, pp. 207, 209; Engbring et al. 1986, pp. 132-133; USFWS 1996, p. 45; Space et al. 2000, p. 4; U.S. Navy 2010, p. 11; U.S. Navy 2014, p. 48).

Wildfire impacts native forest habitat by destroying dormant seeds of native species as well as plants themselves, even in steep or inaccessible areas. Successive fires which originate in

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grasslands and savannas that burn farther and farther into forest edges destroy native plants and remove habitat for native species by altering microclimate conditions favorable to non-native plants. Invasive plant species most likely to be spread as a consequence of fire are those that produce a high fuel load, are adapted to survive and regenerate after fire, and establish rapidly in newly burned areas, such as tangantangan (C.W. Smith, 1985; p. 193; Orwa et al. 2002, p. 2; Walton 2003, p. 35; Wolfe and Bloem 2012, p. 253) and many invasive grass species established in the Mariana Islands (Space 2000, p. 4; USFWS 1996, p. 45; U.S. Navy 2010, p. 11).

Grasses (particularly those that produce mats of dry material or retain a mass of standing dead leaves) that invade native forests and shrublands provide fuels that allow fire to burn areas that would not otherwise easily burn (Fujioka and Fujii 1980 in Cuddihy and Stone 1990, p. 93; D’Antonio and Vitousek 1992, pp. 70, 73–74; Tunison et al. 2002, p. 122). Native woody plants may recover from fire to some degree, but fire often shifts the competitive balance toward non- native plant species (National Park Service 1989 in Cuddihy and Stone 1990, p. 93). Another factor that contributes to wildfires on Guam, and other Mariana Islands that have non-native ungulates, includes land clearing for pasturage and ranching, which results in fire-prone areas of non-native grasses and shrubs (Stone 1970, p. 32; CNMI-SWARS 2010, pp. 7, 20).

Since at least the early 1900s, fire has been formally recognized as a human-exacerbated threat to native species and native ecosystems throughout the Mariana Islands (Bowers 1950, pp. 207, 209). On the island of Guam where its occurrence is particularly well documented, wildfires plague forest and savanna areas annually during the dry season despite the tropical climate, with at least 80% of wildfires resulting from arson (U.S. Navy 2010b (JGPO), p. 1-9). Hunters on Guam, Rota, and Tinian frequently set fires to flush game or to lure game to new growth for easier hunting (Bowers 1950, p. 209; Boland pers comm. 2014; Kremer pers comm. 2014; Willsey pers comm. 2017). As early as the 1899-1914 German administration of the Mariana Islands, arson by hunters was considered detrimental to the remaining forests and subsequently regulated (Bowers 1950, pp. 207, 209). On many of the islands it is not uncommon for these hunter-set fires to become wildfires that spread across large expanses of the savanna ecosystem as well as into the adjacent forest ecosystem. Between 1979 and 2001, more than 750 fires were reported annually on Guam, burning over 155 mi² (401 km²) during this time period (U.S. Navy

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2010b, p. 1-8). Six of these 750 fires burned over 1,000 ac (405 hectares (ha)) (U.S. Navy 2010b, p. 1-8).

All habitats including forest are most susceptible to drying during the drier portion of the year (the winter and spring months), particularly true during an El Nino year. During the El Nino year of 2016, at least three arson-related wildfires on Tinian, likely ignited either for hunting or clearing, affected 100 ac (40.5 ha) or more of tangantangan and secondary-mixed forest habitat in the northern and southern regions of the island (Willsey pers comm. 2017). The three fires occurred in the San Jose homesteads in southwest part of the island, in the Marpo Heights area in the southeast, and the largest fire, which was visible from Saipan when it occurred, in the North Field area of northern Tinian. All of the fires were ignited in grassland, but burned into adjacent forest. As of 2017, all of these burned areas were converted into non-native grasslands ((Willsey pers comm. 2017).

Tangantangan forest is widely known to be susceptible to wildfire (C.W. Smith, 1985; p. 193; Orwa et al. 2002, p. 2; Walton 2003, p. 35; Wolfe and Bloem 2012, p. 253, however in their 1999Enviornmetnal Impact Statement (EIS) for Military Training in the Marians, the U.S. Pacific Command (Appendix F) noted that native forest along cliffsides may burn more readily than tangantangan forest. In their 2010 Guam and CNMI Military Relocation Final (JGPO) EIS, regarding wildfire risk, the U.S. Navy (2010, p. 102) stated that grass fires are regular occurrences on Tinian with greater danger during the dry season. The EIS further cited data cited from the 1997 Tinian INRMP (NAVFAC Pacific 1997) that showed that the highest fire risk exists during the driest months (May through July) of the dry season and during this time 200-250 or more acres may burn each year (U.S Pacific Command 1999, p. ES-9). The EIS also cautioned that “the alteration or removal of habitats by fire could reduce food sources or prevent or inhibit breeding and create competition for feeding and sheltering, particularly for species that establish discrete territories” with significant impacts to those species (U.S. Navy 2010, p. 102). According to the DOD (NAVFAC in litt. 2018, p. 68), live fire training on Tinian is currently restricted to the use of small arms within indoor facilities and open fires are not permitted during training activities.

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We are aware that there is a wide distribution of occasional wildfire occurrence on Tinian. The impacts from these wildfires may range from little or no impact to the Monarch to temporary loss of forest habitat for foraging and breeding to permanent conversion. Conversion of secondary or native forest to grasslands or to forests that regrow with lower diversity of tree species is of the greatest concern of among the possible effects of wildfire. Overall, while wildfire has historically and presently impacts forest habitat needed by the Tinian Monarch, we do not have evidence that its impacts to the forest are such that the Monarch’s species-level viability is notably reduced.

3.2.3 Other Factors

Here, we explore the impacts of additional factors and activities because they may occur on Tinian and could possibly affect the species, but for which we currently lack sufficient data or evidence to determine a measureable impact to the species as a whole.

3.2.3.1 Typhoons

The Mariana Islands are frequently impacted by typhoons, which are the primary documented source of Tinian Monarch mortality via destruction of nests. Additionally, typhoon damager to forests in the Mariana Islands is well documented and results in vast areas of forest stripped of foliage and with downed trees, potentially affecting all three forest types, but native forest is particularly susceptible by typhoons exacerbating the spread of non-native plant species. Although we currently lack definitive studies on the matter, existing initial research suggests that climate change may lead to less regularity of tropical cyclone formation in the region, but more intense strong tropical cyclones in the Mariana Islands when they do occur. Additionally, because the cyclones are a source of rain for the islands during the dry season, their reduced regularity may result in drier dry seasons and increased risk of wildfire (Zhang and Wang 2017, pp. 5,923-5,924).

Other than the aforementioned study (Zhang and Wang 2017, entire), little research regarding climate change indicators specific to the Mariana Islands has been published. However, data collected on climate change indicators from the Pacific Region, (particularly near the Hawaiian Islands) show that, overall, the range in daily temperatures is decreasing, resulting in a more

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consistently warm environment, especially at higher elevations and at night. Predicted changes associated with increases in temperature include, but are not limited to, a shift in vegetation zones upslope, shifts in animal species ranges, changes in avian disease range, exposure, and susceptibility, changes in mean precipitation with unpredictable effects on local environments, increased occurrence of drought cycles, and increases in the intensity and number of typhoons (Loope and Giambelluca 1998, pp. 514–515; Emanuel et al. 2008, p. 365; U.S. Global Change Research Program 2009, pp. 145–149, 153; Keener et al. 2010, pp. 25–28; Finucane et al. 2012, pp. 23–26; Keener et al. 2012, pp. 47−51).

It is reasonable to extrapolate some of these predictions to the Mariana Islands because climate in this area is strongly influenced by the El Niño–Southern Oscillation (Lander and Guard 2013, pp. S192−S194). In addition, weather regime changes (e.g., droughts, floods, and typhoons) will likely result from anticipated increases in annual average temperatures related to more frequent El Niño episodes in the Mariana Islands (Keener et al. 2012, pp. 35−37, 47−51) and elsewhere in the Pacific (Giambelluca et al. 1991, p. iii). However, despite considerable progress made by expert scientists toward understanding the impacts of climate change on many of the processes that contribute to El Niño variability, it is not possible to say for certain whether El Niño activity will ultimately be affected by climate change (Collins et al. 2010, p. 391).

The Mariana Islands lie in the western North Pacific basin, which is the world’s most prolific typhoon basin, with an annual average of 26 named typhoons between 1951 and 2010 (Keener et al. 2012, p. 50). A typhoon is the term used for tropical cyclones located to in the Northwest Pacific ocean (as opposed to tropical cyclones located elsewhere and termed hurricanes) is the generic term for a medium-to large-scale, low-pressure storm system over tropical or subtropical waters with organized convection (i.e., thunderstorm activity) and definite cyclonic surface wind circulation (counterclockwise direction in the Northern Hemisphere) (Holland 1993, p. 7, NOAA in litt. 2011).

Typhoons are seasonal, occurring more often in the summer, and tend to be more intense during El Niño years (Gualdi et al. 2008, pp. 5,205, 5,208, 5,226). The high winds and strong storm surges associated with typhoons—particularly super typhoons, which have winds of at least 150 mi per hour (65 m per second; Neumann 1993, pp. 1–2; NOAA in litt. 2011)—have periodically

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caused great damage to the vegetation of the Mariana Islands. Climate modeling projects changes in typhoon frequency and intensity due to global warming over the next 100 to 200 years (Emanuel et al. 2008, p. 360, Figure 8; Yu et al. 2010, pp. 1,355–1,356, 1,369–1,370); however, there are no certain climate model predictions for a change in the duration of Pacific typhoon storm season (which generally runs from May through November) (Collins et al. 2010, p. 396).

Since approximately 2000, many particularly strong typhoons have originated near or struck the Mariana Islands, including Typhoon Dolphin in 2015, Typhoon Haiyan in 2013, and several other typhoons and super typhoons between 2002 and 2005 (FEMA in litt. 2014). In the previous 20 years (between 1976 and 1997), only eight typhoons reaching the island chain caused damage warranting Federal Emergency Management Agency (FEMA) assistance (FEMA in litt. 2014).

More recently, Zhang and Wang (2017, entire) modeled a downscaled climate forecast for the Western Pacific (including Guam and the Mariana Islands) (110°E–140°W, 0°–39.5°N), which indicates climate change effects including increased temperatures and changes in both rainfall and typhoon frequency may be expected in this region before the end of this century. The study examined two scenarios, both a high and a medium carbon emissions scenario, termed RCP8.5 and RCP4.5, respectively. Results from the study indicate that the surface air temperature in the region surrounding the Mariana Islands is likely to increase 2.7–3.4 °F (1.5–2.0 °C) under the RCP4.5 scenario and 5.4–6.3 °F (3.0–3.3 °C under the RCP8.5 scenario. While the study found that projected annual mean future rainfall changes for the Western Pacific were not statistically significant under either scenario, the results suggested slightly wetter weather under the RCP4.5 scenario and slightly drier weather under the RCP8.5 scenario. Lastly, the study examined the possibility of change in the frequency of typhoons and found that under both emissions scenarios, weak typhoons will largely decrease within 311 mi (500 km) of the Mariana Islands, while strong typhoons will increase.

Researchers believe forest habitat in the island chain has coevolved to adapt under the regular influence of typhoons (Stone 1971, entire; Falanruw et al. 1989, p. 8; Marler et al. 2016, pp. 1, 3). Despite this adaptability, native forests in the Mariana Islands are increasingly invaded by non- native plants that then shift the forest ecology to their own favor allowing them to exploit the

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damaging effects of typhoons (Rodda and Savidge 2007, p. 311; Maler et al. 2016, p. 1). These effects include opened canopy structure, increased availability of light, and creation of disturbed areas conducive to additional invasion. Consequently, forest composition is gradually changing to non-native plant species that compete with decreasingly abundant native plant species for space, water, and nutrients, thereby altering basic water and nutrient cycling processes in some areas (USFWS 2009, p. 279) (see Section 3.3.5 “Invasive plants”).

Tinian has historically and recently experienced high-intensity typhoons, and Zhang and Wang (2017, entire) indicate Tinian will in the future experience higher-intensity typhoons. Typhoons may directly and indirectly impact the Tinian Monarch through at least four mechanisms. According to life history studies of the species (USFWS 1996, pp. 29, 36, 45), typhoons have been known to strip foliage and devastate large areas of forests on Tinian, causing measurable decline in Tinian Monarch nesting activity, and to date, the largest source of documented Monarch mortality via nest destruction. During the first year of the two-year study, Tinian was hit by three storms in the fall of 1994, including tropical storm Vern in mid-October, Supertyphoon Wilda in late October, and typhoon Zelda in November. All Monarch nests documented prior to the storms were destroyed, and observed attempts at nesting activity by breeding pairs ceased for at least six weeks after the storms (USFWS 1996, pp. 29, 36).

Besides reduced nesting success and direct mortality from nest destruction, the Monarch temporarily loses habitat when foliage is drastically stripped from forests across the island depending upon the extent of the typhoon damage (USFWS 1996, pp. 29, 45). Additionally, the Monarch may be impacted by the potentially permanent conversion and loss of native forest habitat due to the creation of canopy openings which allow invasive, non-native plants to encroach at a higher frequency and with greater success (see section 3.4.7 “Invasive plants”).

Although high-intensity typhoons are currently the primary documented cause of Monarch mortality when they occur, the species is known to recover during subsequent nesting seasons. Additionally, while indirect impacts related to increased wildfire risk and native forest habitat conversion are possible, we believe the impacts from typhoons do not rise to the level such that they are impacting the Monarch at the species level.

3.2.3.2 Drought

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Future changes in precipitation in the Mariana Islands are more uncertain because they depend, in part, on how the El Niño–La Niña weather cycle might change (State of Hawaii 1998, p. 2– 10). Zhang and Wang (2017, entire) found that projected annual mean future rainfall changes for the Western Pacific were not statistically significant under the two different emissions scenarios; however, the results suggested slightly wetter weather under the RCP4.5 scenario and slightly drier weather under the RCP8.5 scenario. Regarding past data, for the last 100 years, most of the Pacific has experienced an annual decline in precipitation; however, the western North Pacific (including the Mariana Islands) has experienced a slight increase (up to 14% on some islands; US National Science and Technology 2008, p. 63; Keener et al. 2010, pp. 53–54). Increases in rain are associated with alterations in faunal breeding systems and increases in disease prevalence, flooding, and erosion (Easterling et al. 2000, p. 2073; Harvell et al. 2002, pp. 2,159−2,161; Nearing et al. 2004, pp. 48−49). While these results are possible on Tinian, based on the best available scientific data, we believe increased cycles of drought are a potential concern.

Although the western North Pacific typically experiences large amounts of rainfall annually, drought is a serious concern throughout Micronesia due to the strong seasonality of rainfall in the region and its correlation with the formation of typhoons, limited storage capacity, and small groundwater supplies (Keener et al. 2012, pp. 49, 58, 119). Long periods of decline in annual precipitation result in a reduction in moisture availability, loss of wet forest, an increase in drought frequency, and a self-perpetuating cycle of invasion by non-native drought-tolerant plants, increased risk of wildfire, and increased erosion.

As we know that the Monarch’s nesting activity decreases or ceases during the dry season and depending upon the forest type (USFWS 1996, pp. 29, 37), it reasonable to suggest that the species may be indirectly impacted by the effects of drought upon all forest types, potentially including temporary forest die off due to reduced available moisture. Drought also leaves all forest types more susceptible to wildfire, because less saturation lowers the threshold required by an ignition source to light a fire and increases the likelihood that plants will burn rapidly and completely. Native forest is particularly vulnerable to degradation by drought because any potential die-off would increase its susceptibility to invasion by non-native plants. The open

86 Tinian Monarch SSA Version 1.0 spaces resulting from die-off provide a path for wildfires, should they occur, to spread rapidly. And non-native plants generally provide a higher fuel load that is more easily burned than the native forest. For all of these reasons, forests exposed to drought would be expected to degrade and provide less for the Tinian Monarch’s needs.

Finally, Tinian Monarchs depend on insects both for survival and to feed their young. Drier conditions and forests produce fewer insects which could increase competition both between Monarchs and between Monarchs and other insectivorous birds. The loss or reduction of insect prey would also increase Tinian Monarch mortality and decrease breeding success. However, based on available data, we cannot quantify these impacts at this time.

3.2.3.3 Cattle ranching

Cattle were likely introduced by European settlers and impacting Tinian’s forest beginning in the 1500-1600s (Fosberg 1960, pp. 46-47). Presently on Tinian, the level of ranching is at a historical low and the number of feral cattle is also low, possibly nonexistent; thus, we do not consider either to currently affect the Monarch’s habitat to a great extent except in localized areas where cattle are allowed access to graze in tangantangan and secondary forest habitat. In such instances, cattle can reduce understory vegetation density by grazing, trampling, and moving through the vegetation (Wiles et al. 1990, pp. 176-177). Despite a lack of quantifiable information about current impacts from cattle, we expect impacts to forest habitat, particularly secondary and tangantangan forest, would incrementally increase with any additional increase in the Tinian ranching industry that results in conversion of forest habitat to pasturage, and those impacts would most likely be exacerbated and concentrated upon the southern third of the island if ranching increases in that region or were to be restricted from the military lease areas (Figure 21).

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Figure 21. Cattle grazing in a pasture in southern Tinian (note invasive Lantana camara in the foreground; photograph by Mike Richardson).

Since cattle were introduced to the island by European settlers beginning in the 1500-1600s (Fosberg 1960, pp. 46-47), ranching has often been an important industry on Tinian (Fosberg 1960, p. 54; Conry 1988, pp. 26−28; Wiles et al. 1990, pp. 176-177; Pregill 1998, p. 66; Perry and Morton 1999, pp. 126–127). In 1982, when the initial forest bird survey was completed, there were approximately 6,000 to 7,000 head of cattle on the island, with numbers falling to approximately 4,500 in 1985, 4,000 in 1993, and 2,000 by 1996 (Wiles et al. 1990, p. 176; Lusk et al. 2000, p. 187), and now sitting at a current historical low of approximately 1,500 cattle (Duponcheel pers. comm. 2017). However, recently interest in ranching has renewed, and the number of ranchers on Tinian increased from 10 or 12 ranchers in 2010 to 49 in 2014 (Bagnol 2014, p. 1). Currently, there are 43 cattle ranches of varying size on Tinian, with 37 of those located within the LBA. According to the Northern Marianas College, Cooperative Research Office (Duponcheel pers comm. 2017), many of the ranches currently within the leaseback area may need to be relocated due to proposed development of ranges and other structures, and the U.S. Navy has discussed tentative plans to relocate some ranches (Camacho 2015, p. 1-2).

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Cattle ranching, even well managed, is generally accompanied by some number of free-ranging cattle that are allowed to graze outside of controlled areas. Based on personal communications and observations (USFWS (Marianas Final Listing) 2015, p. 59426; Flores in litt. 2015), we believe the number of feral cattle on Tinian to be currently low, perhaps even nonexistent. However, if the overall size of the cattle industry increases on Tinian so might the risk that cattle may escape and become feral or at least free-ranging outside of designated pastures. Cattle, whether domestic and contained or feral, can drastically alter the landscape (Wiles et al. 1990, pp.) 176−177) , and depending on the location and amount of land designated as pasture land for domestic cattle, negative impacts to all three forest habitat types on Tinian may be expected. Forest habitat grazed by cattle degrades to grassland pasture, and plant cover is reduced for many years following removal of cattle from an area (Wiles et al. 1990, pp. 176−177; USDA, Natural Resource Conservation Service (NRCS) 2015, in litt.). Cattle, feral or otherwise, with access to forest habitat may eat native vegetation, trample roots and seedlings, cause erosion, create disturbed areas into which non-native plants invade (Engbring et al. 1986, p. 8-11; Wiles et al. 1990, p. 177; USFWS 1996, p. 38; Lusk et al. 2000, p. 187), and potentially spread seeds of non- native plants in their feces and on their bodies (Kiviniemi 1996, p. 73; Kiviniemi and Telenius 1998 p. 115; Bartuszevige and Endress 2007, p. 904; Chuong et al. 2016, p. 52).

In summary, based upon the information available to us, we do not believe the ranching of cattle on Tinian is currently influencing the forest habitat inhabited by the Monarch. However, we remain concerned about the future possible impacts to habitat should ranches be relocated to other areas within the LBA (see additional discussion in Section 4.3.4), or should ranching in the LBA be substantially or entirely curtailed, resulting in new and additional ranching pressure to forests in southern Tinian.

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Figure 22. Feral goat within secondary-mixed forest on the island of Pagan (photograph by Mike Richardson).

3.2.3.4 Feral goats

Historically, feral goats have greatly impacted forest habitat on those Mariana Islands inhabited by them, including Aguiguan, Agrihan, Alamagan, and Pagan (Ohba 1994, p. 19; Ritter and Naugle 1999, pp. 275−281; Figure 22). Goats are widely recognized for their capacity inhabit a diverse variety of habitats and their ability to access and forage in extremely rugged terrain (Clarke and Cuddihy 1980, pp. C–19, C–20; Culliney 1988, p. 336; Cuddihy and Stone 1990, p. 64). These attributes allow goats to completely eliminating some plant species from the Pacific islands (Mueller-Dombois and Fosberg 1998, p. 250; Atkinson and Atkinson 2000, p. 21). We believe there is some cause for concern about their potential impact to the Tinian Monarch, in

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part because of their impact on the adjacent island of Aguiguan and because they have been reported on Tinian (Marshall pers comm. 2016).

By the mid-1800s, goats had been transported to the adjacent island of Aguiguan (Butler 1992, p. 15), and by the 1970s concern about the effects of the herds on the island’s vegetation were noted in the literature (Wiles et al. 1990, p. 177). Despite an aborted attempt by the CNMI government to eradicate the herds in the late 1980s, a population of approximately 1,000 goats was estimated by 2002 (USFWS 2009, p. 280). This explosion in the number of goats has resulted in the almost complete loss of understory plants, leaving only two native plant species unpalatable to goats, Cynometra ramiflora and Guamia mariannae, and the near destruction of the native forest’s ability to regenerate in response to the intense grazing pressure (Wiles and Worthington 2002, p. 7; Cruz et al. 2000, pp. 3, 4; Esselstyn et al. 2004, pp. 304, 307; Cruz et al. 2008, p. 243; USFWS 2009, pp. 279, 280; Wiles et al. 2011, pp. 300-301).

Since the early 1900s, large herds of goats have periodically occurred on Tinian, particularly in the southern part of the island near Kastiyu, and within a variety of habitats including native forest (Wiles et al. 1990, pp. 171, 177). In our report to the U.S. Navy regarding our 2008 surveys of Tinian (USFWS 2009, p. 280), we noted that approximately 200 goats had been recently transported from Aguiguan and released into Tinian native forest to propagate as per instructions of the Mayor of Tinian. A survey around the coast on October 11, 2008 by Service biologists confirmed a herd of at least 20 goats at Puntan Kastiyu (14°56'53.90"N 145°39'53.38"E), which were already creating trails, accelerating erosion, and impacting the native vegetation on the hillside. Subsequently, in April 2016, Service biologists reported seeing approximately two dozen free-ranging goats again in Southern Tinian, crossing the highway near Suicide Cliffs (Marshall pers comm. 2017; Willsey pers comm. 2017).

Besides these recent sightings of feral goats, we have no other direct evidence that the goat population may be affecting Tinian Monarch habitat. However, based upon their capacity for tremendously impacting forest habitat Aguiguan and elsewhere, we are concerned about the potential for impact to forest habitat if their numbers are allowed to expand, particularly in southern Tinian, home to approximately 52% of the population and containing 66% of the remaining native forest on the island.

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3.2.3.5 Invasive plants As reported from many islands in the Pacific region, the impacts of native forest degradation and alteration by non-native plants in Guam and the Mariana Islands are well-established. The impacts include the alteration of the wildfire regime and the creation of large swaths of monotypic stands of non-native species, particularly tangantangan, that out-compete and crowd out native plants. Although native forest is only one of three forest types utilized by the Tinian Monarch, because it is the most productive habitat in terms of reproductive success, home-range sizes, and densities (see section 2.4.2 “Native forest value to the Tinian Monarch”), further degradation could lead to decreased Monarch densities in those areas.

The native flora of the Mariana Islands (plant species that were present before humans arrived) consisted of no more than 500 taxa, 10% of which were endemic (species that occur only in the Mariana Islands). On Tinian alone, over 206 plant taxa have since been introduced from elsewhere (Koob in litt. 2018, entire), and at least one-third of these have become pests (i.e., injurious plants) (Stone 1970, pp. 18–21; Mueller-Dombois and Fosberg 1998, pp. 242–243, 249, 262–263; Costion and Lorence 2012, pp. 51−100). Of these non-native pest plant species, at least nine species are known to be habitat-altering, including shrubs such as lantana, grasses such as fountain grass, and ironically, tangantangan (Wiles et al. 1990, pp. 168, 177; Space et al. 2000, entire; College of Natural Sciences 2017, entire).

The U.S. Navy has identified the transport of military equipment and materials to Tinian for training or other purposes as a likely source of introduction of new invasive plant species to the island (U.S. Navy 2015, p. 4-212). However, as a requirement of the MITT BO (USFWS 2015, Appendix B), the U.S. Navy in March 2017, implemented the establishment of invasive species rapid response capability, which requires baseline and early detection monitoring of invasive plant, invertebrate, and small vertebrate species, and ensures washdown standards through inspections of all cargo, equipment, and vehicles moving between Guam and Tinian or internationally during training activities (NAVFAC in litt. 2018, p. 80). The most likely source of civilian introduction of non-native plant species is inadvertent or intentional transport of soil, seeds, or plants and seeds intended for ornamental use, particularly by nurseries, or, for example,

92 Tinian Monarch SSA Version 1.0 by farmers, for some other use without knowledge of their deleterious effects (Space and Falanruw 1999, p. 6; Space et al. 2000, p. 7).

In general, non-native plants degrade native forest habitat in the Mariana Islands by (1) modifying the availability of light through alterations of the canopy structure, (2) altering soil- water regimes, (3) modifying nutrient cycling, (4) altering the fire regime affecting native plant communities (e.g., successive fires that burn farther and farther into forest habitat, destroying native plants and removing habitat for native species by altering microclimatic conditions to favor non-native species), and (5) ultimately converting native-dominated plant communities to non-native plant communities (Thaman 1974, p. 23; Smith 1985, pp. 217–218; Cuddihy and Stone, 1990, p. 74; Matson 1990, p. 245; D’Antonio and Vitousek 1992, p. 73; Ohba 1994, pp. 17, 28, 54–69; Vitousek et al. 1997, pp. 6–9; Mueller-Dombois and Fosberg 1998, pp. 242-243, 249, 262–263; Berger et al. 2005, pp. 45, 105, 110, 218, 347, 350; CNMI-SWARS 2010, pp. 7, 9, 13, 16).

We believe the greatest risk to the Tinian Monarch is posed by those non-native plant species that are particularly aggressive in displacing native species and exacerbate encroachment of non- native species and grasses into native forest patches by altering the fire regime. One of the most invasive plants on Tinian is lantana (Space and Falanruw 1999, p. 2), a malodorous, branched shrub up to 10 ft (3 m) tall, first brought to the Mariana Islands as an ornamental plant and first reported from Tinian in 1930 (Kanehira 1931, in Thaman 1974, p. 36). Lantana is aggressive, thorny, and forms thickets, crowding out and preventing the establishment of native plants (Davis et al. 1992, p. 412; Wagner et al. 1999, p. 1,320). Recognized as a serious pest species in Micronesia by the 1940s (Denton et al. 1991, pp. 72, 75), lantana was reported as abundant and widespread on Tinian in the 1990s, particularly in the southern portion of the island (Denton et al. 1991, pp. 72, 74; Space and Falanruw 1999, p. 9). Ungulates can exacerbate the spread of lantana and other non-native plants as has occurred on the adjacent island of Aguigan, where goats facilitate lantana’s spread by eating nearly everything with the exception of lantana (Thaman 1974, p. 23; Denton et al. 1991, p. 72).

Another invasive of concern is tangantangan. Even though Monarchs nest within and inhabit tangantangan forest, the species is widely considered invasive in many parts of the world. Native

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to the neotropics, tangantangan is a nitrogen-fixing shrub and an aggressive competitor that often forms the dominant element of the vegetation (Geesink et al. 1999, pp. 679–680). It alters the chemistry of soils on Tinian (Marler et al. 2016, p. 1) to its own benefit and now covers approximately 29 % of the island (Table 13).

Additionally, several particularly invasive plant species are located on Rota, Saipan, and Guam and not presently found on Tinian including ivy or scarlet gourd (Coccinia grandis), molasses grass (Melinis minutiflora), and fountain grass (Pennisetum setaceum), among many others (Space et al. 2000, pp. 2–5), all of which could easily harm native and other forest habitat should they be introduced to the island through military or civilian activities. Furthermore, many non- native species including lantana and molasses and fountain grasses exacerbate fire ecology (Thaman 1974, p. 23; D’Antonio and P. M. Vitousek 1992, pp 63-87; Space and Falanruw 1999, p. 3).

As discussed in section 2.4 “Forest Habitat and the Tinian Monarch,” the Tinian Monarch depends on forest habitat for its survival at both the individual and species levels, and would not be able to survive or breed without it. More particularly, the Monarch depends on the remaining 5% native forest to provide the highest quality habitat for its feeding, breeding, and sheltering needs. Based upon the information available to us, we have no basis to believe that the capacity of non-native plants to degrade either native or secondary-mixed forest through conversion is currently influencing the abundance of Tinian Monarchs. However, we remain concerned about the future possible cumulative impacts to those two forest types given the possibility of exacerbation by climate change, wildfire, and typhoons.

3.2.3.6 Predation

Rats

Due to their impacts to island fauna and flora, rats are recognized as one of the most destructive invasive vertebrates worldwide, causing major ecological, economic, and health effects (Atkinson 1985 p. 35; Cuddihy and Stone 1990, pp. 68–69; Atkinson and Atkinson 2000, pp. 23– 24; Figure 23). Three rat species, all non-native, are currently found on Tinian, including the Polynesian rat (Rattus exulans), known to occur in the Mariana Islands since at least 1,000–1,200

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AD based upon fossil records (Steadman 1999, p. 319); the Norway rat (R. norvegicus), first reported from Saipan in the late 1800s and considered rare on Tinian (Kuroda 1938 in Wiewel et al. 2009, p. 208); and R. rattus species complex Lineage IV (sensu Aplin et al. 2011) hereafter referred to as the black rat; a southeast Asian rat likely introduced following European colonization of the Mariana Islands (Wiewel in litt. 2018; Wiewel et al. 2008, unpublished USGS report).

Among the three rat species known to occur on the island of Tinian, the Polynesian rat is generally considered the least detrimental to birds as a predator compared to the other two rat species (Atkinson 1985, p. 37; Thibault et al. 2002, p. 161; Towns et al. 2006, p. 863; and Jones et al. 2008, p. 16), including on other Pacific islands where it is established. During a study of nesting success and nest predation of several native bird species in several habitat types on Saipan between 2003 and 2004, Sachtleben (2005, entire), hypothesized that rats would be the pre-dominant nest predator, but found that native birds including the Micronesian starling were the primary culprit. However, it is possible that Sachtleben’s characterization of Ratttus rattus (a demonstrably aggressive predator) inhabiting Saipan was a misidentification as demonstrated later by Wiewel et al. (2009, entire). Impacts from rat predation may also more closely correspond to specific species and their nesting habits. In a study of Nightingale Reed-Warblers (Acrocephalus luscinia luscinia) on the island of Saipan, researchers found overall nesting success for the species to be only 44% with 71% of the nest mortality attributed to predation by Rattus sp. (Mosher in litt. 2006, p. 54).

Wiewel et al. (2009, entire), conducted the most extensive study to date of introduced small mammals in the Mariana Islands, examining the density, distribution, and biomass of all three above described rat species, as well as the house mouse (Mus musculus) and the Asian house shrew (Suncus murinus), on the islands of Guam, Rota, Saipan, and Tinian between 2005 and 2007. Rat density within native forest was sampled on Rota, Saipan, and Tinian, but not on Guam. The study surveyed rat density in secondary-mixed forest on Guam, Rota, and Saipan and in both tangantangan forest and grassland on all four islands. Because of the BTS’s presence, both the density and the biomass of all five small mammals were found to be much lower on Guam compared to Rota, Saipan, and Tinian (Wiewel et al. 2009, p. 210). Overall, the black rat was the most abundant of the rodents studied, and densities on both Rota and Tinian were

95 Tinian Monarch SSA Version 1.0 unusually high compared to results from rodent density studies on other tropical islands (Wiewel et al. 2009, p. 205).

Although we have neither direct nor anecdotal evidence to suggest that the Tinian Monarch is being impacted by rat predation, the high densities documented by Wiewel et al. (2009) suggest that non-native small mammals, especially the black rat, may be potentially affecting the abundance and diversity of the native fauna and flora of the Mariana Islands, including the Monarch. Given the Monarch’s low nesting height and a 20% mortality rate, a rate which is slightly higher than that recorded for other similar Pacific island-endemic Monarchs (VanderWerf et al. 2007, p. 5), we believe possible predation by rats should be further investigated during future study of the species. Wiewel et al. (2009, p. 217) also suggested that the high densities of rats and shrews on Rota, Saipan, and Tinian might affect avian species through dietary competition, particularly problematic for nesting birds when nestlings require high-protein prey such as insects.

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Figure 23. Photograph of black rat gorging on papaya within tangantangan forest on northern Tinian (photograph by Mike Richardson).

In addition to potential existing impacts to the Monarch from one or more of the three rat species currently inhabiting Tinian, there is always the possibility that a new, invasive small mammal predator, including possibly a new rat species, will be introduced to and become established on the island. As noted previously, wide-ranging impacts including extinction of Pacific island- endemic avifauna from different rat species are well-documented (Atkinson 1985, pp. 35, 37; Thibault et al. 2002, p. 161; Towns et al. 2006, p. 863; and Jones et al. 2008, p. 16). Although apparently not present on Tinian, the effects from the black rat (Rattus rattus) on native Hawaiian birds and their nests are well-documented, including predation on the Maui creeper (‘alauahio, Paroreomyza montana) (Baker and Baker 2000, p. 10), the puaiohi or small Kauai thrush (Myadestes palmeri) (Snetsinger et al. 2005, p. 72; Tweed et al. 2006, p. 753), the crested honeycreeper (akohekohe, Palmeria dolei) (Simon et al. 2001, p. 736), the Oahu elepaio (VanderWerf and Smith 2002, p. 73; VanderWerf 2009, p. 737), and the palila (Loxioides bailleui) (Pletschet and Kelly 1990, p. 1,017). Rat predation has had major negative effects on

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some of these species, including the puaiohi (Tweed et al. 2006, p. 753), the palila (Pletschet and Kelly 1990, p. 1,017), and the Oahu elepaio, a Monarch flycatcher species (VanderWerf 2009, p. 737).

The impacts of black rats on other island-endemic avifauna, including Monarch species such as the Tahiti Monarch flycatcher, are clearly documented elsewhere in the Pacific, including New Zealand and French Polynesia. In Eastern French Polynesia, the entire Monarch genus Pomarea endemic to the high volcanic islands of the Cook, Society, and Marquesas archipelagos, has become imperiled by the effects of forest habitat loss and particularly by predation by black rats (Ciboise et al. 2004, pp. 37 39; Robertson and Saul 2007, p. 7; Blanvillain and Ghestemme 2013, p. 3). Recent extinctions of five of the species have been documented on several islands, and the remaining five species in the genus are considered threatened or at risk of extinction from black rat predation and habitat loss. Studies of the group have indicated that predation by the black rat is the most serious of the threats to this French Polynesian Monarch genus. Indeed, some species have been documented to persist on their respective islands even with a majority of the forest habitat lost, only to quickly become extirpated or extinct following the establishment of the black rat to that island (Thibault et al. 2002, pp. 161-162).

Because of the possibility of substantial impacts to the Tinian Monarch from predation by invasive rat species, we believe additional study of the potential effects of the island’s three documented species, along with improved biosecurity to prevent additional small mammal introductions to the CNMI, is warranted.

Cats

Cats (Felis catus) have been present on Tinian since at least the 1800s and feral cats have been recorded since the 1970s including far from human habitation during mammal surveys in the mid-1980s (Wiles et al. 1990, pp. 174-175. Although we lack evidence of feral cat predation upon the Tinian Monarch, effects to endemic birds from cat predation are well-established and the risk is greater to species that nest relatively close to the ground, like the Monarch (Banko et al. 2004, p. 162; Hess and Banko 2006, p. 2; Maui Forest Bird Recovery Project 2015; Scott et al. 1986, pp. 363–364; Tweed et al. 2006, p. 753). During the post-delisting studies, researchers

98 Tinian Monarch SSA Version 1.0 noted that fewer Monarchs were recorded during surveys near urbanized areas (USFWS 2009, p. 234), where feral cats are often observed to occur on the island. Consequently, we believe possible predation by cats should be further investigated during future study of the species.

Monitor lizards

The monitor lizard has consistently been identified as a predator of the Tinian Monarch and was identified in the petition to list (CBD 2013, p. 19; Figure 24). The monitor lizard (Varanus indicus), a carnivorous, arboreal lizard that can grow up to 5 ft (1.5 m) in length (NAVFAC in litt. 2018, p. 86), is widely present throughout the Mariana Islands, including on Tinian (Vogt and Williams 2004, pp. 76–77), its presence predating European contact (Vogt and Williams 2004, p. 77). However, several studies involving stomach analyses of dozens of monitor lizards on several islands in the region densely inhabited by monitors indicate that small birds are consumed infrequently (S. Vogt pers. comm. 2016). Despite its varied diet, which is known to include coconut crabs, snails, snakes, lizards, skinks, fish, rats, sea turtle eggs, and birds (Berger et al. 2005, pp. 69–70, 90, 347–348; Losos and Greene 1988, pp. 379, 393; Bennet 1995 in ISSG-GISD 2007, in litt.) and one possible observation of Monarch egg predation documented during the 1994–1995 Monarch life history studies (USFWS 1996, p. 37), we lack clear evidence of monitor lizard predation on the Tinian Monarch. However, we believe possible predation of the Monarch by monitors should be further investigated during future study of either species on Tinian.

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Figure 24. Photograph of adult monitor lizard hiding in dead tree in mixed forest on Pagan (photograph by Mike Richardson).

3.2.3.7 Avian pox

During the Service’s post-delisting monitoring studies which occurred between 2006 and 2011, researchers unexpectedly discovered netted Monarchs infected with the pox virus, the first documented outbreak in the Mariana Islands of a wild bird species with the disease. In 2006, 39% of the captured Monarchs exhibited scabby lesions on their feet and toes (Figure 25) consistent with lesions caused by the avian pox virus (later confirmed to be pox virus (Atkinson pers comm. 2014)); in 2007, 11% of the captured Monarchs had pox-like lesions; and in 2009, a single bird, 3% of those captured, had pox-like lesions (pox lesions were not observed during the 2008 study). The pox-like lesions were observed only in Monarchs and not in any of the other species captured during the 5-year study, which may indicate that the Monarch were possibly more susceptible to pox than other birds on the island. Since the post delisting monitoring studies

100 Tinian Monarch SSA Version 1.0 were concluded in 2009, we are aware of Monarchs only being captured and handled during 2015 and again in 2016 (approximately 50 birds each year) for the CNMI DFW effort to translocate the species to the island of Guguan (DFW in litt. 2016, pp. 1-2). During both the 2015 and 2016 translocation efforts, all captured Monarchs appeared healthy and no signs of pox infection were observed (Mullin pers comm. 2017).

Amidon et al. in litt. (2016, p. 13) hypothesized that the decreasing rate of pox lesions and the near lack of observations after 2007 perhaps indicated the tail end of an epizootic or a cyclical occurrence. Amidon et al. in litt. (2016, p. 13) found in 2006 some indication that prevalence of the pox lesions was higher at the Santa Lourdes Shrine and the Seaport study sites, both closer to the urbanized areas of Tinian where mosquito abundance may be higher as a result of standing water in residential structures and abandoned machinery that provide mosquito breeding sites. In Hawaii, where pox is better studied, the southern house mosquito (Culex quinquefasciatus) is believed to be a common vector for both the virus and avian malaria (LaPointe et al. 2012, p. 221). This mosquito species is also the likely primary pox vector on Tinian (Rueda et al 2011, p. 25). The mosquito breeding sites in the urbanized areas of Tinian are also closer to populations of domestic birds, such as chickens, which could serve as a reservoir for disease. Further development on the island is likely to increase artificial rainfall reservoirs, such as improperly disposed of garbage, cleared land, and paved sites, leading to a higher mosquito population and greater risk of pox transmission.

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Figure 25. Photograph of pox-like lesions on the foot of a Tinian Monarch captured during the 2006 study (photograph by Eric VanderWerf).

Avian pox (or bird pox) is an infection caused by the virus Avipoxvirus, which produces large, granular, and eventually necrotic (causing tissue to die) lesions or tumors on the exposed skin or diphtheritic (affecting the mucous membranes) lesions on the mouth, trachea, and esophagus of infected birds. Avian pox can be transmitted through cuts or wounds upon physical contact or through the mouth parts of blood-sucking insects. Tumors or lesions caused by avian pox can be crippling for birds and may result in death.

Other than Savidge et al. (1992, p. 213), which noted that pox may have been present within the Guam chicken population since as early as 1915, we lack historical data for avian pox occurrence in wild bird populations in the Mariana Islands. However, some perspective is provided by accounts from the Hawaiian Islands, where observations of native birds suffering from avian pox were documented as early as 1902 (Warner 1968, p. 106) and confirmed from museum specimens dating from the early 1900s (Jarvi et al. 2008, p. 339). Existing data from studies in Hawaii suggest that mortality from avian pox may range from 4–10% in Oahu elepaio with

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active lesions (VanderWerf 2009, p. 743) to 100% in Laysan finches (Warner 1968, pp. 108– 109). Current infection rates for the Tinian Monarch due to avian pox are unknown.

In Hawaii between 1977 and 1980, Van Riper et al. (2002, pp. 929–942), collected and examined 15,000 native and non-native forest birds for pox virus lesions and determined that native forest birds were more susceptible than introduced species, that all species were more likely to be infected during the wet season, and that pox prevalence was greatest in areas with the greatest overlap between birds and vectors. Many studies of avian pox have also documented that native birds are frequently infected with both avian pox and avian malaria (Van Riper et al. 1986, p. 331; Atkinson et al. 2005, p. 537; Jarvi et al. 2008, p. 347). This high rate of infection may be due to mosquito transmission of both pathogens simultaneously, or because documented immune system suppression by the pox virus renders chronically infected birds more vulnerable to infection by or a relapse of malaria (Jarvi et al. 2008, p. 347), or due to other unknown elements.

VanderWerf (2009, p. 743) has also suggested that mortality levels from pox may correlate with higher rainfall years, and at least in the case of the elepaio, observed mortality may decrease over time with a reduction in susceptible birds. The Tinian Monarch has not been studied as well as the elepaio, and we have no information on its rate of mortality as related to avian pox. We believe the possible impacts to the Monarch from avian pox should be further investigated during future study of the species.

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Chapter Four: Future Condition

4.1 Factors Influencing Future Viability - Overview

This Chapter outlines our assessment of the Tinian Monarch’s condition in the future and presents likely scenarios of environmental conditions and the consequences of those conditions on the ability of the Tinian Monarch to sustain its population over time. A primary part of our analysis of the future condition of the species was a risk assessment of the establishment of BTS on Tinian. The Monarch’s survival depends on preventing the introduction of BTS on Tinian, a possibility that is associated with military and civilian activity on the island and the level and quality of interdiction to prevent its introduction to the CNMI.

In addition, our analysis explored the impact of future military and civilian development on Tinian’s forest habitat. As established in previous chapters, the Monarch depends upon the island’s three forest habitat types (limestone, secondary-mixed, and tangantangan) for survival and particularly its reliance upon the limestone, or native, forest. Any removal or alteration to forest habitat will have an impact on the Monarch’s viability. Therefore, in our assessment of the future condition of the Monarch, we relied in part on projected changes in the use of forest habitat by military and civilian development, as well as impacts from associated activities such as wildfire.

Our military land-use projections relied upon several sources: the U.S. Navy’s current lease, the prior Mariana Islands Range Complex (MIRC) biological opinion, and more recent U.S. Air Force Divert Activities and Exercises (DIVERT) and MITT biological opinions. As noted previously, the U.S. Navy has a lease with the CNMI government to utilize the northern two- thirds of Tinian for an initial term of 50 years which expires 2033, with the option for a renewal for another 50 years (2033–2083). In 2015, the U.S. Navy has also proposed the CNMI Joint Military Training effort (CJMT) effort in a Draft Environmental Impact Statement (DEIS), which outlined military training development and activities that would include the removal or alteration of forest habitat. The CJMT DEIS proposes a series of construction and operational actions on Tinian in three alternatives similar in scope and scale. All three alternatives also would involve land-use agreements, support and training facilities, infrastructure, and training

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operations, all of which build and expand upon the directives under the MITT and MIRC programs.

The island of Tinian is also subject to civilian development, which is difficult to predict for a number of reasons. Civilian development projects on Tinian are, to a certain extent, dependent upon the extent of military development, both positively and negatively. In other words, some military development will likely encourage civilian development while some military development may discourage civilian development, and civilian and military forces differ in their projections of the effects. In considering civilian development, we therefore balanced information contained in the 2015 CJMT DEIS with the CNMI government’s comments upon the DEIS (CNMI 2015 entire) using our own projections.

With the information on the risk of BTS establishment and this information on civilian and military development, we developed future scenarios of the Tinian Monarch’s condition that are based primarily on potential activities related to military and civilian development, BTS interdiction efforts, and to a lesser degree, the increased risk of habitat loss from wildfire as a result of associated military and civilian activity. These anthropogenic and environmental factors considered in our future scenarios are outlined in the following sections and diagramed in Figure 26, below.

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Figure 26. Conceptual model demonstrating how the anthropogenic and environmental factors considered in our future scenarios influence the habitat and demographic factors of the Tinian Monarch, which contribute to the overall viability of the species.

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4.2 Brown treesnake (BTS)

4.2.1 Overview

Beginning in the late 1940s, the island of Guam experienced the tragic, near-complete loss of its native forest bird avifauna due to the establishment of the brown treesnake (Boiga irregularis, BTS; Figure 27). Because Guam and many Pacific islands, including Tinian, share similar climates, biological features, and avifaunal communities, establishment of BTS on other Pacific Islands would likely result in similar decimation of bird populations, and for Tinian this would include the Tinian Monarch. Specifically, Guam and Tinian share a tropical climate and dense tropical foliage, and like pre-BTS Guam, Tinian still has an extremely high rodent and lizard density. These factors facilitated the relatively rapid BTS population growth on Guam following its establishment, particularly the abundance of prey including high densities of introduced rats, mice, shrews, and lizards that are an ideal food source for BTS (Rodda and Savidge 2007, p. 315; Campbell et al. 2012, p. 1,194). Because of the severe threat posed by BTS, Territorial, Federal, States, and international countries’ efforts to contain BTS on Guam and prevent its spread to other islands were implemented, maintained, and improved as feasible over time.

The interdiction program to keep BTS out of cargo departing Guam is now better than it has been in the past due to tremendous improvements to methodology and DOD, Federal and Territorial agency, and private industry efforts during the past ten years. Nevertheless, interdiction efforts can never be expected to prevent 100% of pest movements and therefore as long as BTS are on Guam other Pacific Islands remain at risk. Even with the current fairly stringent interdiction programs in place, Tinian remains vulnerable to BTS invasion based on its proximity to Guam, the current volume of civilian air and sea cargo traffic between Guam and the CNMI, on-going DOD activities, and anticipated increases in rates of civilian and military activity (Perry and Vice 2008, pp. 994, 996; U.S. Navy 2015, entire; BTSWG 2016, p. 6; USGAO 2017, p. 20).

If an incipient BTS population became established on Tinian or elsewhere in the CNMI, our current options for control and eradication are limited. Presently, those options include the

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measures that the BTS Rapid Response Team would employ such as visual searches, trapping, and inspection with dogs, toxicant baiting, and possibly combined with some application of the aerial bait delivery systems (ADS). Developed to suppress BTS populations on Guam and currently showing great promise for this purpose for areas as large as 1,235 ac (500 ha), (Clark and Savarie 2012, p.216; Dorr et al. 2016, pp. vii-x; Siers et al. 2017, pp. 1-2), eventual use of ADS for eradication appears unlikely due its inability to effectively target smaller snakes, its high cost, and other logistical and administrative challenges (BTSWG 2016, p. 28).

4.2.2 The Brown Treesnake

The BTS—native to northern Australia, Papua New Guinea, and Melanesia—was inadvertently introduced to Guam in the late 1940s via military cargo following WWII reclamation efforts (Rodda et al. 1992, p. 53; Rodda and Savidge 2007, p. 307). The number of snakes that established the population on Guam is unclear, with estimates ranging from a single pregnant female (BTSWG 2016, p. 1) to up to ten individuals originating from the Admiralty Archipelago, Papua New Guinea (Richmond et al. 2014, p. 1). Genetic data suggest the BTS population on Guam exhibits low genetic diversity due to founder effects, yet this has not hindered the species’ invasive success on Guam (Richmond et al. 2014, p. 1).

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Figure 27. Photograph of brown treesnake (Boiga irregularis) showing its striking eyes adapted for nocturnal life (photograph by Bjorn Lardner).

After its arrival on Guam in the late 1940s most likely at the Naval Seaport, the BTS encountered an abundance of prey, but few predators, competitors, or pathogens, allowing the arboreal, nocturnal BTS to spread steadily across the island to occupy Guam’s entire 31.7 mi (51 km) length and 210 square miles. It is estimated that the BTS increased its population by 40 % annually before reaching capacity and spread northward at a rate of approximately 2 km per year over the course of 25 years (Rodda and Savidge 2007, p. 317). At its peak in the 1980s, the BTS population on Guam was estimated at two million individuals and in favorable habitats reached densities in excess of 40 snakes per acre (100 per hectare) (Rodda and Savidge 2007, p. 315), vastly exceeding the 2-per-acre average elsewhere for densities of large non-aggregated snakes (Parker and Plummer 1987, p. 255). By the mid-1990s and following the near complete loss of Guam’s native and vulnerable forest bird avifauna and lizard fauna, BTS densities had declined to approximately 20 snakes per acre (50 per hectare) (Rodda and Savidge 2007, p. 315). Now sustained primarily by non-native prey including lizards, rodents, and birds, Guam BTS densities

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remain at similar, still extraordinarily high levels (Clark and Savarie 2012, p. 218; Siers in litt. 2015, p. iv), thus presenting tremendous risk from an invasion perspective (Stanford and Rodda 2007, p. 176; BTSWG 2016, p. 5). Presently, BTS still occupy all known habitats on Guam with varying densities by habitat type (Mathies et al. 2010, p. 209; Siers in litt. 2015, p. iii) with the best fed snakes generally recorded in savanna and grassland (Rodda and Savidge 2007, p. 314; Siers in litt. 2015, p. iii), corresponding to the highest introduced small mammal densities by habitat type recorded by Wiewel et al. (2009, p. 205).

The BTS is possibly the most intensively studied of all Boiga species, and yet much remains unknown about its basic biology and reproduction, both in its native range and in Guam. What we do know has been well-summarized in Savidge et al. (2007, entire) and Rodda and Savidge (2007, entire), particularly regarding its capacity as a capable invader resistant to control tactics. The BTS exhibits several attributes that increase its capability to invade and simultaneously hinder our ability to control or eradicate the species using many techniques potentially available to manage invasive species. Perhaps foremost, BTS in Guam appear to breed year-round compared to BTS in its native range where breeding habits are seasonally limited by temperature, moisture, or prey density (Savidge et al. 2007, p. 193; Mathies et al. 2010, p. 209). This capacity for year-round breeding is a tremendous logistical impediment to the development of a contraceptive control strategy for BTS. Likewise, disruption of BTS breeding by chemical control appears to be precluded by the species’ use of several different chemicals during courtship (Rodda and Savidge 2007, p. 316; BTSWG 2016, p. 37).

Renowned for their large and striking eyes, the BTS appears to be highly dependent on its eyesight for capturing prey (Figure 27). Unlike many snake species that may pursue prey on chemical cues alone, the BTS will cease pursuit of prey absent of visual cues, an attribute that challenges our ability to control it using chemical baits or lures (Rodda and Savidge 2007, p. 315). Like all snakes, the BTS eyes lack a tapitum lucidum, the reflective membrane present in the eyes of many nocturnal animals, and thus they cannot be easily detected at night by searching for their reflection from light sources (Rodda et al. 1999, p. 72; Lardner et al. 2007, p. 234).

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According to Rodda et al. 1999 (p. 72), the BTS is an extraordinary climber, able to exploit almost any natural environment, as exemplified by its near extirpation of the cave dwelling Mariana swiftlet from Guam (Cruz et al. 2008, p. 233), demonstrating that few natural areas are inaccessible to the species. Well-adapted to disturbed habitats, the BTS can also be found in close proximity to developed areas. Challenging our ability for detection, the nocturnal, cryptic, and secretive BTS uses its extremely thin body advantageously to conceal itself in spaces unsuitable for most animals, including in and around items which may be being prepared for off island shipment such as cargo and cargo boxes as well as both air and sea craft. During cargo searches, aggregations of up to 11 snakes have been discovered, crammed together in short pieces of pipe (Rodda et al. 1997, p. 72), an indication of its incredible ability to remain undetected in transport to new localities and the very real potential for one or more snakes to be accidentally shipped off island.

Despite the species’ proclivity for living in proximity to humans on Guam, the BTS is easily stressed under conditions of captive rearing, a characteristic that has challenged our ability to understand many aspects of the species’ biology, particularly its reproduction (Rodda and Savidge 2007, p. 315). For example, the BTS has only been observed mating on a total of three occasions, and only in its native range in the wild. During studies of BTS in the 1980s, a substantial number of snakes were captured and autopsied, unfortunately revealing little information about female reproduction other than an apparent tendency for inactivity during pregnancy when they seemingly disappear. Furthermore, only a couple of mature, gravid females containing eggs were examined, and a small percentage of those examined contained sperm within their reproductive tract. Likewise, only a few nests with eggs have ever been discovered opportunistically despite years of searching and research (Savidge et al. 2007, pp. 193-195).

The possibility of female BTS reproducing through parthenogenesis (a form of asexual reproduction) has been previously identified as a potentially serious BTS interdiction concern because an incipient population could be established by a single female (Savidge et al. 2007, p. 197; Booth and Schuette 2015, p. 1). While only the primitive Brahminy blindsnake (Ramphotyphlops braminus) is known to reproduce by obligate parthenogenesis, more recent

111 Tinian Monarch SSA Version 1.0 research is revealing that many additional species of snakes that otherwise reproduce sexually are also capable of facultative (optional) parthenogenesis both in captivity and in nature (Booth and Schuett 2015, pp. 1, 7). Two possibly related species, Thamnophis elegans vagrans and T. marcianus, have been observed reproducing by facultative parthenogenesis (Schuette et al. 1997, pp. 2-4; Booth and Schuette 2015, p. 4). However, because there is some uncertainty surrounding the Colubridae family taxonomy (Weinstein et al. 2011, pp. 2-3), their relatedness to Boiga spp. is not clear, and it is still uncertain whether the BTS requires both males and females to reproduce.

Of similar concern is the unresolved issue of female BTS capacity to store sperm, particularly the duration of sperm storage, and its implications for establishing an incipient population with only a single female (Siers et al. 2017, pp. 2, 12). As noted previously, studies of autopsied BTS during the 1980s revealed that females were found to contain sperm in their reproductive tract. However, conclusions in the literature on whether female BTS in Guam (or their native range) store sperm (or evolved that capacity) and how that relates to what is known about male reproduction is both contradictory and presently undecided. For example, Whittier and Limpus (1996, p. 591) found an absence of seminal receptacles in the female oviduct suggesting that either longer-term sperm storage may not commonly occur, or that the BTS lack obligatory oviducal sperm storage. Conversely, Bull et al. 1997 (p. 478), found storage of sperm by the male BTS is tied to seasonality in part of its native range and may be a relict of the species’ origin in Asia where greater seasonality occurred. Mathies et al. 2010 (p. 209) have demonstrated that male BTS in the Guam population produce sperm year-round, possibly precluding the need for females (in Guam) to store sperm. Despite the uncertainty surrounding both the potential for BTS to reproduce parthenogenetically or the female BTS to store sperm, neither possibility can be ruled out at this time and both scenarios increase the risk of establishment from the Guam source to the island of Tinian or elsewhere in the CNMI particularly given the proximity of the islands.

Based upon the available, albeit limited, data on reproductive biology, Rodda and Savidge (2007, p. 316) proposed that the high density of BTS on Guam is probably achieved through high survivorship rather than exceptional fecundity. Indeed, beyond the occasional mortality from

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dogs, pigs, cats, or possibly monitor lizards, there are no natural predators on Guam or in the CNMI to control the species, unlike in its native range in Indonesia and Australia. Although the topic of biocontrol is occasionally broached in the literature, the technique would remain risky even if a possibly suitable agent from its native range could be identified (Rodda and Savidge 2007, p. 318; BTSWG 2016, p. 37). However, on a related and hopeful note, Richmond et al. (2014, pp. 9-10) indicate that research may eventually reveal an angle to control BTS by taking advantage of the species’ limited genome; particularly if its genes regulating immunity are limited, the species may be more susceptible to infection or disease, potentially allowing for management of the species with parasites or pathogens. For example, some BTS on Guam are known to harbor parasites but the prevalence and impacts from such parasites has yet to be fully explored (Holldorf et al. 2015, p. 1).

4.2.3 Loss of Guam avifauna to BTS predation

The scope and scale of the decimation of Guam’s avifauna due to BTS predation is clearly illustrated by the island’s ecological disruption from the loss of normal seed dispersal and pollination services provided by the extirpated birds (and bats). This disruption has been sufficiently extensive to impact Guam’s forest structure and perhaps permanently alter its ability to regenerate (Fritts and Rodda 1998, p. 129; Perry and Morton 1999, p. 137; Ritter and Naugle 1999, p. 275−281; Rodda and Savidge 2007, p. 311; Mortensen et al. 2008, p. 2,146; Rogers et al. 2013, pp. 4-6; Caves et al. 2013, pp. 1−9). Establishment of the BTS on any island in the CNMI, including Tinian without a rapid response action, would likely result in a similarly swift, catastrophic fate for its native avifauna and associated ecosystems (BTSWG 2016, p. 6) in addition to tremendous impacts to cultural resources, the local economy and increased costs for biosecurity.

The BTS is believed responsible for the extinction, extirpation, or decline of 13 of Guam’s 22 (59 %) native bird species, including all of the native forest bird species with the exception of the Micronesian starling (Wiles et al. 2003, p. 1,358; Rodda and Savidge 2007, p. 307; Table 14). The most comprehensive study of the decline (Wiles et al. 2003, entire) analyzed survey data

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gathered between 1976 and 1998 and reviewed unpublished sources to provide a comprehensive account of the impact of the BTS on the island's birds. The results indicated that 22 species were severely impacted by the BTS, including 17 of 18 native species. Twelve species were extirpated as breeding residents on the main island (Guam), eight species experienced declines of greater than or equal to 90 % throughout the island, and two species persisted at reduced population levels during all or much of the study. The study found that in areas newly invaded by the BTS, observed declines of avian species were greater than or equal to 90 % and occurred rapidly, averaging just 8.9 years. The study also examined traits of the birds that made them more or less susceptible to BTS predation, and determined that the ability and tendency to nest and roost in locations where snakes were less common correlated with greater likelihood of coexistence with BTS. Large clutch size and large body size correlated with a species’ greater persistence, although large body size appeared to delay, but not prevent, extirpation.

Table 14. Species of native birds, lizards, and bats impacted by brown treesnakes on Guam. (Sources: BTSWG 2016, p. 50; Wiles (1987, 2005); Wiles et al.2003, entire) Common name Species Status Birds ** Guam flycatcher Myiagra freycineti Extinct * Micronesian kingfisher Todiramphus cinnamominus Extirpated / Captive pop. only / FE * Guam rail Gallirallus owstoni Extirpated / Captive & introduced pop. / FE * White-throated ground Gallicollumba xanthonura Extirpated dove * Mariana fruit-dove Ptilinopus roseicapilla Extirpated ** Rufous fantail subspecies Rhipidura rufifrons uraniae Extinct * Nightingale reed-warbler Acrocephalus luscinia Extirpated / FE * Micronesian honeyeater Myzomela rubrata Extirpated * Guam bridled white-eye Zosterops conspicillatus Extinct * Mariana crow Corvus kubaryi Extirpated / FE White-tailed tropicbird Phaethon lepturus Extirpated Brown booby Sula leucogaster Extirpated Brown noddy Anous stolidus Nearly / Temporarily extirpated White tern Gygis alba Decline *Mariana swiftlet Aerodramus bartschi Decline >90% / FE

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* Micronesian starling Aplonis opaca Decline >90% / FE Mariana common moorhen Gallinula chloropus guami Decline / FE Bats Pteropus mariannus Mariana fruit bat Decline >90% / FE mariannus Little Mariana fruit bat Pteropus tokudae Presumed Extinct / FE Reptiles Island gecko Gehyra oceanica Decline >90% Micronesian gecko Perochirus ateles Extirpated Mutilating gecko Gehyra mutilata Decline Slevin’s skink Emoia slevini Extirpated / FT * = Forest bird species ** = A flycatcher species in the Monarchidae family and related to the Tinian Monarch FE = Federally Endangered species FT = Federally Threatened species

4.2.3.1 Monarchine flycatchers extirpated from Guam by the BTS

Among the species impacted by the BTS on Guam were two birds in the Corvoidea superfamily, the Guam flycatcher (Myiagra freycineti) and the Rufous fantail subspecies (Rhipidura rufifrons uraniae), both of which were endemic to Guam but now are extinct due to predation by the BTS. Both of these insectivorous passerines shared many biological similarities with the related Tinian Monarch, including a preference for forest habitat, territorial behavior, and nesting height from the ground (Engbring et al. 1986, pp. 69-70; Jenkins 1983, pp. 42-44). If the BTS is established on Tinian, there is little reason to expect the Tinian Monarch would not follow a similar fate given the large amount of evidence of BTS impacts to Guam’s avifauna and these two related and ecologically similar flycatcher species.

Guam flycatcher

A relative of the Tinian Monarch in the Monarchidae family, the insectivorous Guam flycatcher was endemic to the island of Guam and an early casualty of the establishment of BTS on Guam (Figure 28). The species was called “Chuguanguang” in the Chamorro language, and was also

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known as the Guam broadbill due to its wide bill with long “whiskers” which helped to locate its food. A relatively small bird at 5 in (13 cm) long, the Guam flycatcher lived in native limestone and ravine forests, mangroves thickets, and tangantangan forests.

Previously a commonly observed species and widely distributed on the island in many habitat types (Jenkins 1983, pp. 35-36), the Guam flycatcher was possibly already being extirpated in Southern Guam according to results from surveys in the mid-1960s. By 1983, Jenkins (1983, pp. 35-36) noted that the species was largely restricted to the very northernmost cliff line forests of Guam and was in danger of extinction. Later studies determined that the slow extirpation of many of Guam’s native birds including the Guam flycatcher was due to the establishment of the BTS on Guam in the 1940s and its steady migration northward across the island (Savidge 1987, entire; Wiles et al. 2003, entire).

Figure 28. Guam flycatcher (photograph by Anne Maben).

Rufous fantail

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The rufous fantail was an insectivorous passerine in the Rhipiduridae family. It was endemic to Guam and closely related to R. f. saipanensis, the subspecies endemic to both the islands of Saipan and Tinian. Like the Guam flycatcher, it was once widely distributed across Guam and commonly observed in relatively high numbers (Jenkins 1983, pp. 36-38). By 1983, it too was restricted to the mature forests of northern Guam and by the late 1980s was considered extinct from the island due to predation by the BTS (Savidge 1987, p. 661; Wiles et al. 2003, entire).

4.2.4 Guam as springboard for the BTS invasion

After realization of the situation on Guam caused by the BTS, reports of snakes, many apparently BTS, arriving in locations around the globe began to emerge. These reports included a handful of live BTS captured in locations such as Alaska, Oahu, Saipan, Oklahoma, and Texas (McCoid et al. 1994, p. 365; Stanford and Rodda 2007, p. 178). The BTS have been known to survive in shipments departing Guam and encountered several months later when shipments were opened and being unpacked (McCoid et al. 1994, p. 365). As the Guam BTS interdiction program has developed and improved over the years, reports of BTS encounters in novel locations have declined in number but still persist on an irregular basis. Nonetheless, Stanford and Rodda (2007, p. 177) reported approximately 93 (unverified) snake sightings in the CNMI between 1978 and 2007, indicating that some BTS were likely being transported from Guam during this time frame. According to Stanford and Rodda (2007, p. 177), of those 93 sightings, 10 occurred on Tinian and 78 occurred on Saipan.

Based upon an in-prep United States Geological Survey (USGS) manuscript (Yackle-Adams and Reed, unpublished), a different, but overlapping dataset specifically for Saipan was examined by a panel of nine experts in an effort to determine if BTS were established on Saipan. The panel analyzed information collected for 96 reported sightings between 1982 and 2013 and concluded that most of the 96 reported sightings (70%) were not credible for BTS. That assessment did not include captures or observations of other snake species on Saipan which have occurred, nor the seven instances of confirmed captures or encounters of dead BTS on the island between 1990 and 2000 (USGS in litt. 2017).

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Despite general improvements in BTS interdiction since the early 2000s and the determination that BTS is not established on Saipan based upon the small the number of credible sightings there, many credible BTS sightings have occurred outside of Guam since 2002. Approximately 25 sightings (or series of sightings) including 15 between 2002 and 2007 and 10 since 2008, were sufficiently credible to trigger response actions or rapid response searches (Table 15), mostly in the CNMI.

Table 15. Rapid response searches due to credible brown treesnake (BTS) sightings in the Commonwealth of the Northern Mariana Islands (CNMI), 2002 to 2016 (USGS in litt. 2017). Island Rapid Response Efforts Tinian Saipan Rota Maui, Kauai, Yap, Pohnpei # of rapid response searches / response actions due to 4† 14 2≈ 1* credible sightings / series of sightings # of rapid response interceptions (captured 0 0 0 0 snakes) * One rapid response each † Two responses occurred days apart ≈ Rota rapid response included one sighting and a single live snake captured in a trap near the airport

4.2.5 BTS risk management efforts

The realization in the mid-1980s that the BTS was responsible for the devastation of Guam’s avifauna and for frequent power outages, prompted management responses from a range of Federal, State, and territorial agencies. Several pieces of Federal legislation and interagency agreements have been instrumental in providing a regulatory framework under which BTS interdiction and prevention are currently managed. This framework includes the Endangered Species Act of 1973 (currently the principal regulatory mechanism supporting interdiction actions); the Nonindigenous Aquatic Nuisance Prevention and Control Act (1990); the

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Amendment to the Lacey Act of 1900 (1992); the Memorandum of Agreement on Control of the Brown Tree Snake in 1993; the National Invasive Species Act (1996); and Executive Order (EO) 13112 Invasive Species (1999) (later amended to EO 13751 in 2016). The U.S. Congress more specifically recognized the BTS threat as part of the Nonindigenous Aquatic Nuisance Prevention and Control Act of 1990, the Brown Tree Snake Control and Eradication Act of 2004 (which established the BTS Working Group), and most recently in 2009 with the passage of the Duncan Hunter National Defense Authorization Act For Fiscal Year 2009. The last Act required that “[t]he Secretary of Defense shall establish a comprehensive program to control and, to the extent practicable, eradicate the brown tree snake population from military facilities in Guam and to ensure that military activities do not contribute to the spread of brown tree snakes.”

Civilian and military interdiction on Guam and in the CNMI, and in particular the use of trapping, baiting, visual and fenceline searches, and detector dog teams, are the principal means of preventing the spread of BTS from Guam to the CNMI (BTSWG 2016, pp. 23; 40). These same mechanism are also utilized elsewhere, including Hawaii. Additionally, rapid response capacities exist and are utilized as a secondary line of defense if a credible snake encounter report is filed. Research on BTS biology, detection and control methodology supports interdiction and response efforts. Outreach plays a critical role in preventing the dispersal of the BTS from Guam by informing the general public and personnel dealing with cargo and conveyances outbound from Guam and inbound to the CNMI and is key for early detection efforts in the CNMI, as reporting of snake encounters by informed and engaged residents and visitors is the primary mechanism supporting use of existing response capacity.

4.2.6 BTS interdiction funding

Expenditures for BTS interdiction and control have steadily increased since the program’s informal inception in 1987 and following the establishment of detector dog teams on Guam in the early 1990s (BTSWG 2016, p. 24). Since its inception in 1987 up through and including 2016, BTS control, research, and interdiction efforts in Guam, the CNMI, and Hawaii has required $100M in total funding with support in recent years exceeding $7M annually, peaking

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at more than $9M in 2010, and then dropping to $7.5M in 2012. The Department of the Interior (DOI) has provided the majority of the funding, with a total contribution of $51.5M including the initial support for the Brown Treesnake Working Group (BTSWG). Since 1990, the majority of BTS funding from the DOI has been provided by the Office of Insular Affairs (OIA) through grants from its technical assistance program (BTSWG 2016, pp. 32, 40). In addition, the role of Endangered Species Act (ESA) consultations related to the funding of BTS interdiction is likely to remain a constant as shipping and transport increase from Guam in the future.

Coinciding with the entry of United States Department of Agriculture Animal and Plant Health Inspection Services (USDA-APHIS) - Wildlife Services into the BTSWG, sustained support from the DOD began in 1994 with approximately $40M in funding support provided to date. Currently the DOI – Office of Insular Affairs (OIA) primarily funds BTS interdiction in support of civilian sector activities on Guam, the CNMI, and Hawaii, while the DOD primarily funds BTS interdiction in support of military sector activities on Guam and the CNMI. Several regulatory mechanisms (e.g., Biological Opinions, Installation BTS Instructions, and DOD Transportation Regulations) ensure consistent BTS interdiction funding for DOD-related and Port Authority of Guam activities, prompting the creation of regulations and procedures, such as the Defense Transportation Regulation, Part V and Installation BTS Instructions for Naval Base Guam and Andersen Air Force Base.

Although total monetary DOI and DOD contributions to the BTS program are comparable, the funds from each agency generally support different programmatic areas. Most DOD funds are directed towards interdiction and control efforts on Guam, with periodic support for research to develop BTS control methods. The latter is for specific multi-year programs (e.g., DOD Legacy and Environmental Security Technology Certification Program). Compared with DOD funding, DOI funds are more widely dispersed across programs. For example, from 2009 through 2012 DOI provided funding support for interdiction efforts on Hawaii and the CNMI, restoration on Guam, early detection and rapid response (EDRR), and BTS research (BTSWG 2016, p. 32). From 1998 to 2010, USDA-APHIS also provided substantial program support, totaling $8.3M, with Wildlife Services receiving these funds (BTSWG 2016, p. 32).

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4.2.7 BTS interdiction tools

Currently, a complex matrix of techniques and methodologies developed primarily by the National Wildlife Research Center (NWRC) and USGS are utilized to prevent BTS transport from Guam and its establishment elsewhere such as islands in the western Pacific (including the CNMI, Okinawa, and many other locations), Hawaii, Diego Garcia, and the US mainland. The primary components of the BTS interdiction program include trapping, toxicant bait stations, visual searches, detector dog teams, barriers and informed staging, sanitation, and shipping policies. Several of these elements are further described in subsequent sections.

4.2.7.1 Barriers and Areas of Quarantine

Strategic air and ship cargo staging, sanitation, and shipping policies, procedures, and facilities including quarantine areas and barriers are the first line of defense against BTS on both Guam and the CNMI. Guam currently lacks permanent snake-proof barriers at its several cargo loading installations at both civilian and military sites, so there is no safe quarantine area for holding or storing outbound cargo that has already received inspection (Cravalho in litt. 2018, p. 1). Because of this lack of a secure quarantine holding area on Guam (i.e., permanent snake-proof barrier), all cargo (i.e., palletized, containers, and/or equipment for general or tactical use) are subject to repeated inspections in an isolated area, and re-inspected prior to the actual loading. The use of a temporary barrier may be used to reduce the number of repeated inspections conducted, but the cargo must be re-inspected prior to loading for transport to the CNMI (Cravalho in litt. 2018, p. 116).

Currently in the CNMI, only the seaport on Tinian has a permanent snake-proof barrier that provides a safe containment and holding area for the inspection of inbound cargo arriving by boat. The Rota seaport currently lacks a permanent snake barrier and the seaport permanent snake barrier on Saipan (Figure 29) remains unsecure from damage caused by Typhoon Soudelor in August of 2015. The Saipan seaport facility barrier is scheduled for repairs in the fall of 2018 (Cravalho in litt. 2018, p. 1). Additionally, as noted below in section 4.2.10.3 regarding the CJMT DEIS, the DOD has committed to construction and maintenance of a

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biosecurity facility on Tinian to be located at the seaport (U.S. Navy 2015, pp. 44-45 (ES-20- 21)), although it is not clear from the DEIS if the facility will include an additional quarantine barrier.

All three main CNMI airports (Rota, Saipan, and Tinian) currently lack a permanent cargo inspection quarantine area with a snake-proof barrier, although a future facility is planned for Tinian’s airport as part of the U.S. Air Force’s DIVERT program (USFWS 2012, pp. 11-14) (see discussion below in section 4.2.10.2). At those CNMI facilities which lack a permanent snake proof barrier (currently all of them except for the Tinian seaport), high risk cargo must either be inspected immediately upon disembarkation, held within temporary barrier containment zones, or reloaded onto the transporting vessel until inspection can be accomplished (D. Cravalho pers comm. 2017). Vegetation and clutter is controlled at all of the above mentioned facilities to minimize the opportunities for BTS to hide and exit cargo undetected.

Besides their initial high cost, one challenge of using permanent (or temporary) BTS barriers for cargo, their susceptibility to typhoon damage as exemplified by impacts to facilities in 2002 when Super Typhoon Pongsona hit Guam (BTSWG 2016, p. 23) or when Typhoon Soudelor damaged the BTS snake containment barrier at the seaport on Saipan in 2015 (Erediano (Marianas Variety) 2016, p. 1). Although Wildlife Services has since made improvements to their program to prevent a similar occurrence on Guam, the BTSWG (2016, p. 33) identified the need for greater disaster planning and programmatic capacity as well as additional infrastructure to ensure that the BTS interdiction program is less vulnerable to storms in the future particularly in the CNMI.

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Figure 29. Photograph of permanent brown treesnake containment and inspection barrier at the seaport on Saipan (currently nonfunctional; photograph by Brand Phillips).

4.2.7.2 Dog inspections of air and ship cargo outbound and inbound from Guam

In conjunction with quarantine zones and suppression techniques, the use of dogs trained to detect BTS are currently considered the most effective means of inspecting cargo and is used as the last line of defense for outbound and inbound cargo (Figure 30). Use of dogs for the purpose of inspecting cargo for BTS began on Guam in the early 1990s and in the CNMI by the late- 1990s (BTSWG 2016, p. 24; Cravalho pers comm. 2018). Snakes found by dog detection are often contained in high risk cargo destined for vulnerable areas, including the CNMI and Tinian (Vice et al. 2009, p. 198). In addition, snakes detected by dogs tend to be smaller snakes that have evaded other levels of detection such as trapping and nighttime searches (Vice et al. 2009, p. 198).

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Between 2012 and 2017, Wildlife Services dog teams on Guam have been detecting an annual average of approximately five to seven snakes in cargo outbound for the CNMI, the majority of those, approximately 80%, in military cargo (Gosnell pers comm 2017; Wildlife Services in litt 2017). However, this cannot necessarily be interpreted to mean that DOD cargo is necessarily more infested with snakes. For example, as it could mean that more DOD cargo is outbound from Guam, DOD cargo is more likely to be infested with BTS, or that a greater proportion of DOD cargo and vessels are getting inspected more often and more thoroughly (see discussion above). Currently, Wildlife Services does not track civilian and military cargo by volume, but rather by the number of inspections of cargo, which could be of size ranging from a single box to as shipping container, although full vessels (boat and aircraft) are counted individually according to Wildlife Services. According to USGS data, since 2000 (the last observation on Saipan), no dog team or inspector in the CNMI has detected snakes within inbound cargo from Guam that was inspected prior to departure by Wildlife Services (USGS in litt. 2017).

The efficacy of dog detection has been tested using live, planted snakes in cargo with earlier studies showing detection rates ranging from 62-75 % (Engeman et al. 1998, entire; Engeman et al. 2002, entire; Vice et al. 2009, pp. 199-200). More recently, these trials are conducted as part of the WS’s Bullseye program and for several years detection rates have ranged between 73 to 88 % (Gosnell pers comm. 2017). Errors in detection may be attributed to insufficient search patterns, failure of the handler to see indications from the dogs that snakes are present, or during the use of less experienced dogs and / or handlers (Vice et al 2009, p. 200; Gosnell pers comm. 2017). In addition to some lack of accuracy in detecting snakes, the primary challenge in use of dogs as part of the overall BTS interdiction strategy is the high cost associated with the program (BTSWG 2016, pp. 28-30, 35-41).

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Figure 30. Photograph of the Commonwealth of the Northern Mariana Islands Division of Fish and Wildlife detector dog team (Paulie and her handler) inspecting cargo on Saipan (photograph by Kevin Donmoyer).

4.2.7.3 Trapping

In conjunction with quarantine barriers, trapping for BTS is on-going at all the aforementioned facilities including outbound cargo quarantine areas on Guam, inbound cargo quarantine areas on Rota, Saipan, and Tinian, and at airports on all four islands as well as many other Guam

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installations and facilities. The attractant is a live mouse housed in a separate smaller cage inside the main snake trap. Each mouse is provided with food and moisture. On the outer perimeter of a containment zone (quarantine area), traps are situated along forest edges and fence lines surrounding ports and areas where cargo and vehicles are packed and staged for shipping (Figure 31).

The current trap design, devised in 1995-96 by the NWRC, is very effective on Guam in capturing snakes measuring 40 in (102 cm) in length or larger. However, due to limitations of the design and differences in prey preferences, the traps are largely ineffective in capturing smaller snakes, which typically feed upon small lizards and for which local populations are not suppressed around inspection facilities as is done for rodents. Tests with reptile-baited traps have thus far proven unsuccessful in capturing smaller snakes and consequently there is no effective means for toxicant baiting or trapping snakes less than 30 in (76 cm) in size (BTSWG 2016, p. 2, 29, 67), althought these snakes can be detected visually and with detector dog teams.

While live-mice trapping of BTS is highly effective in capturing snakes on Guam where they are abundant and rodent prey is relatively scarce, research has shown that capture rates are inversely related to non-native small mammal density. In other words, where prey are abundant BTS are less attracted to mouse-baited traps, so capture rates decrease. For example, Rodda et al. (2001, as quoted in Wiewel et al.. 2009, p. 218) found a strong correlation (r2 = 0.90) between BTS trap capture rates and small mammal density and documented a 7-fold increase in BTS capture rates in areas of very low rodent density on Guam. Similarly, Gragg et al. (2007, p. 2,311) documented a 22–65% increase in BTS trap capture probability after reducing rodent populations in grasslands in Southern Guam with localized rodenticide application. These findings call into question the effectiveness of live-mice traps during rapid response actions and around containment zones on Tinian, Rota, and Saipan where small mammal densities may be extremely high (Wiewel 2009, p. 205; BTSWG 2016, pp. 6, 30).

In addition to their relative ineffectiveness in the CNMI and limitations in capturing smaller snakes, the other significant challenge with trapping is the high cost and labor intensity involved in rearing live mice and long term checking and maintaining of trap lines.

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Figure 31. Photographs of live mice traps in use on the island of Guam. Traps are often secured to containment fencing in this manner (photographs by Brand Phillips).

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4.2.7.4 Nighttime searches

Tall chain-link security fencing surrounds the airports on Guam, Rota, Saipan, and Tinian and many outbound cargo inspection facilities and installations on Guam. During the night, spotlight searches of these fence lines have been shown to be an effective means of capturing snakes (on Guam) in pursuit of foraging geckos climbing on the fence. This technique is effective for targeting smaller-sized snakes, which are not as susceptible to capture in traps or toxicant bait take as noted above in section 4.2.7.3 (BTSWG 2016, p. 29).

4.2.7.5 Rapid response

Initiated in 2002 and administered by the USGS as part of their BTS research efforts, the Rapid Response Team supports local authorities as feasible with training response personnel and as requested through deployment for ground actions related to BTS encounter reports. The Rapid Response Team office also supports at-risk jurisdictions with outreach and awareness activities. The main purpose of the Rapid Response Team is to quickly deploy whenever a credible snake sighting is reported on a snake-free island; to locate, capture or kill any snakes found; and to determine if an incipient population is present.

In a response deployment, the Rapid Response Team can be supported by visual searchers who are part of the USGS BTS research program on Guam. These searchers paired with locally trained team members as well as untrained local staff are the core of most BTS response actions, which to date have depended heavily on nighttime visual searching as the primary tool for snake detection. At times, other tools may also be deployed, including mouse-baited snake traps and detector dog teams. Currently, training for team members is based on the ability of agencies to send staff to Guam for three weeks of initial intensive training and then conduct week-long follow-up training every two to three years afterwards. Active team membership varies but ranges between approximately 34 and 70 members, with hundreds of individuals trained over the years. The majority of team members are State and Federal employees in Hawaii, CNMI Department of Lands and Natural Resources (DLNR) staff in the CNMI and USGS BTS research

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staff and contractors. See additional discussion below in section 4.2.11 about the Rapid Response Team in regard to its role as a line of defense should BTS become established on Tinian or elsewhere.

4.2.8 BTS Interdiction on Guam

BTS interdiction and prevention activities are largely coordinated on Guam where they are currently managed through several layers of legislation and interagency agreements. Several Federal agencies are involved including the USFWS, USGS, USDA, and the National Park Service (NPS), which coordinate their activities and cooperate with the DOD (see discussion immediately below and section 4.2.9) and several Guam partner agencies including the Guam Department of Agriculture Division of Aquatic and Wildlife Resources, the Port Authority of Guam, the Guam International Airport Authority, and the Guam Power Authority.

The lead agency for interdiction on Guam is the USDA-APHIS Wildlife Services, which oversees control, containment, and inspection efforts on Guam for departing cargo at both military and civilian ports (air and sea), as well as dozens of other areas where high-risk cargo is packed and consolidated (staged). The tools and techniques used by Wildlife Services to control, contain, and suppress BTS on Guam include live-mice baited traps, toxicant bait stations, nighttime visual searches, dog inspections, and BTS-proof barriers (BTSWG 2016, p. 19). These components of interdiction are applied by Wildlife Services at various levels and in different combinations to create multiple layers of protection at dozens of facilities and installations on Guam wherever high-risk cargo, including vehicles, is packed and staged for shipment to vulnerable areas (particularly tropical areas where BTS would thrive).

Broadly, the main categories of outgoing DOD and civilian cargo departing Guam for the CNMI include commercial and military vehicles, equipment, supplies, personal vehicles (cars and trucks), household goods, and vessels including military, commercial and private sea and air craft. Since at least 2007 (Rodda and Savidge 2007, p. 311) through the present (Wildlife Services in litt. 2017), DOD cargo comprises the majority of cargo departing Guam based on the

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number of inspections (actual percent is unreported) (Gosnell pers comm. 2017). Beginning in 2011, Wildlife Services has achieved an approximately 99.5 % inspection rate for DOD cargo and vessels (sea and air craft) departing Guam for the CNMI (BTSWG 2016, p. 16). However, Wildlife Services does note that some military cargo and vessels miss inspection on Guam.

In 2016, several civilian vessels and cargo including, five aircraft, three boats, and 128 cargo items (of unknown size and volume) bound for the CNMI on the Wildlife Services manifest for inspection did not get inspected on Guam. All of the 128 missed cargo inspections involved cargo transported by the commercial transportation system as opposed to military transport. When cargo misses inspection on Guam, Wildlife Services notifies inspectors within the CNMI where the vessels are due. According to Wildlife Services, military cargo missing inspection on Guam has always received inspection within the CNMI. For civilian cargo or vessels that miss inspection on Guam, Wildlife Services can only report a given incident to CNMI-DFW inspectors, but does not currently have a means to confirm that the cargo or vessels are actually inspected (Gosnell pers comm. 2017).

4.2.9 BTS Interdiction in the CNMI

In 1996 the CNMI was added to the 1993 Memorandum of Agreement on Brown Treesnake Control as a participating agency (renewed in 2011) in the working relationship between the DOI, DOD, USDA, GovGuam, Hawaii DOT, and the National Invasive Species Council (NISC). The CNMI has passed two bills that mandate the prevention of the introduction of invasive animals such as BTS into the commonwealth, including the 1978 Commonwealth Plant and Animal Quarantine Act (2 CMC Section 5301) and the 1985 Animal Health Protection and Disease Control Act (2 CMC Sec 5320), the latter of which established a well-defined system of animal quarantine, inspection procedures, and disease control activities to provide for the sound protection of domestic and pet animals, poultry and other birds, and public health. The lead CNMI agency responsible for BTS biosecurity is the CNMI DLNR, which uses Federal funding provided by OIA and USFWS to inspect all cargo from Guam (CNMI DLNR 2005, p. 7), address reports of snake sightings, and conduct BTS awareness programs. Additionally, the CNMI DLNR manages and operates air and seaports in the CNMI, facilitates inspection

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processes, and provides logistical support including maintaining containment barriers and dog facilities. Currently, the CNMI DFW successfully inspects about 95% of all inbound aircraft, vessels, and cargo from Guam

In the CNMI, including on Tinian, the CNMI DFW administers and employs methods similar in theory to those in use by Wildlife Services on Guam. Dog inspections are used as well as temporary and permanent BTS-proof barriers for high-risk cargo arriving from Guam. As needed, arriving cargo can be secured in a barrier system until a thorough inspection can be conducted and the material released. Additionally, BTS traps are used around all port and cargo containment areas. As noted previously, however, the efficacy of BTS trap-lining in the CNMI is unknown given the abundance of non-native rodents and both native and non-native lizards and birds present.

As part of the CNMI, Tinian’s BTS program is also administered by the CNMI DFW, although the DOD often oversees its own inspections of cargo arriving from Guam (see below, section 4.2.10 Need for BTS Interdiction for Military Activities on Tinian). The majority of (recorded) civilian cargo (by air and ship) received on Tinian arrive from Guam via Saipan or Asia via Saipan. However, military equipment and goods may be flown or shipped directly from Guam to Tinian (USFWS 2015b [MITT BO], pp. 21, 57-58). Therefore, the primary mechanism for the potential establishment of BTS on Tinian is through the indirect transportation of commercial goods from Guam via Saipan or through the direct transportation of military cargo and equipment from Guam.

According to the BTSWG and Service reports, the CNMI DFW’s interdiction program, responsible for cargo inspection in the CNMI including Tinian, has since its inception, frequently experienced challenges meeting performance measures, and these hurdles remain a pressing concern (BTSWG 2016, pp. 17, 23, 27, 39; Campbell pers comm. 2017). For example, the island of Tinian currently lacks an on-island BTS detection dog (K. Donmoyer pers comm. 2017), although a dog is periodically sent from Saipan to assist with certain inspections as needed. Additionally, as of 2017 live mice are bred on Saipan and are sent to Tinian as needed for the 40 traps total maintained at both the airport and seaport (K. Donmoyer pers comm. 2017).

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According to Wildlife Services (Gosnell pers comm. 2017), several private and commercial, primarily vessels, depart Guam for the main CNMI islands each year without an inspection by Wildlife Services and are possibly not inspected by dog teams when arriving in the CNMI, which potentially means a substantial amount of cargo bound for the CNMI is not getting inspected at all. Consequently, the lack of reporting, enforced inspections, and overall performance of the BTS interdiction program in the CNMI in general and on Tinian specifically, suggests that capacity for interdiction should be improved to address a range of currently fluid levels of incoming commercial boat and air traffic. Presently, the program’s lack of capacity presents a high risk for inadvertent introduction of BTS (see additional discussion below regarding our risk analysis).

Both in the past and recently, the CNMI DLNR, the USFWS, and OIA have collaborated on efforts to improve the CNMI’s BTS program (Cravalho in litt. 2017). One solution proposed for improving the CNMI’s BTS program is to have the USDA-APHIS Wildlife Services administer the program as they do for all Guam-outbound cargo (BTSWG 2016, p. 43; Campbell in litt. 2017). However, should the administration of the CNMI BTS program transition to Wildlife Services, subsequent increases in the program’s costs are anticipated and would need to be managed so as not to diminish the amount of funding available to the overall BTS control and management effort, including ongoing research and education programs (Reed pers comm. 2017; Cravalho pers comm. 2017).

Currently, most experts agree that an incipient BTS population is not established on Saipan (BTSWG 2016, pp. 5, 16, 40) or elsewhere in the CNMI including Tinian. However, should the BTS become established on Saipan, the number of potential sources in the region would be doubled, greatly exacerbating the risk of introduction to Tinian or elsewhere in the CNMI (Perry and Vice 2009, p. 998; BTSWG 2016, p. 5).

4.2.10 Need for BTS Interdiction for Military Activities on Tinian

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The Department of Defense is an integral cooperating agency partner and works with the Service to protect natural resources in the Marianas and wherever our respective agency interests overlap. Governed by several mandates and directives to protect against the spread of BTS from Guam, the DOD has a long track record of supporting and funding BTS research and interdiction in Mariana Islands region. Within the region, there are several specific component groups of the DOD involved in BTS interdiction support, described briefly below.

o Commander Navy Installations Command (CNIC)

o Naval Facilities Engineering Command, Headquarters (NAVFAC HQ)

o Joint Regions Marianas (JRM)

o Andersen Air Force Base (AAFB)

o Naval Base Guam (NBG)

o Naval Facilities Engineering Command, Pacific (NAVFAC Pacific)

o Naval Facilities Engineering Command, Marianas (NAVFAC Marianas)

o Armed Forces Pest Management Board (AFPMB)

As noted above in section 4.2.9, DOD cargo comprises the majority (actual percent unreported) of all cargo departing Guam for the CNMI as quantified by inspection events. Wildlife Services is employed by the DOD to inspect military cargo before it departs Guam for the CNMI, and where CNMI-DFW administers inspection upon arrival. When CNMI DFW staff cannot logistically handle DOD cargo inspections on a given island, for example when simultaneous flights arrive to different portions of Tinian or when military exercises require a cargo volume that exceeds DFW capacity, the DOD are mandated to transport and use Wildlife Services staff from Guam to inspect incoming cargo and equipment (BTSWG 2016, p. 19; Cravalho pers comm. 2017). Additionally, according to the DOD (NAVAC in litt. 2018, p. 117), all DOD exercises on Tinian regardless of the use of DFW or Wildlife Services BTS inspectors, also involve the oversight of Environmental Office personnel which ensure 100% redundant BTS

133 Tinian Monarch SSA Version 1.0 inspections occur as well as other non-BTS biosecurity requirements for clean military vehicles and equipment. Due to the aforementioned problems with the DFW program consistency, including periodic lack of an active detector dog team and the absence of live mice for BTS trapping on Tinian, the need for Wildlife Services assistance on Tinian has become a more frequent occurrence (Cravalho pers comm. 2017).

Within the CNMI, the majority of military activities and cargo movement are currently occurring on the islands of Tinian and Saipan. Current and some planned future actions are being driven by several larger DOD directives and maneuvers in the Pacific region, including the relocation of Marines from Okinawa to Guam, the Mariana Islands Range Complex (more recently superseded by the Mariana Islands Training and Testing Area (MITT) initiative), and the U.S. Air Force’s Divert Activities and Exercises project. With expansion of DOD involvement in the Marianas, we expect increased activity at Guam’s air and seaports in the near future including both military and civilian cargo and conveyances are expected to increase in volume and frequency. Consequently, we have consulted with the DOD regarding cargo shipments between Guam and Tinian with the goal of improving BTS biosecurity as part of the overall objective of protecting Tinian’s native flora and fauna, including the Tinian Monarch.

4.2.10.1 Mariana Islands Training and Testing Area (MITT)

In 2014, the U.S. Navy initiated consultation on the Mariana Islands Training and Testing Area (MITT) program to supersede the Mariana Islands Range Complex (MIRC) directive for training and military activities in the Mariana Islands including Tinian. The MITT program replaces the MIRC program for nearly the same activities conducted by the U.S. Navy, U.S. Air Force, U.S. Army, U.S. Coast Guard, and the U.S. Marine Corps on Guam, Rota, Tinian, Saipan, and Farallon de Medinilla (FDM), although the U.S. Navy is the designated lead Federal action agency for purposes of conducting ESA consultation on the program.

In general, the MITT program governs the strike warfare training and use of FDM, amphibious warfare training on Guam and Tinian, Naval warfare training on Guam, Rota, Tinian, Saipan, and FDM, and other activities. Specifically regarding Tinian, the MITT program includes an expansion of the training exercises and activities previously planned to occur on the island under

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the MIRC directive. Broadly, these activities include increases beyond the MIRC program for amphibious warfare and Naval special warfare training on Tinian that would increase the amount of amphibious assaults, amphibious raids, urban warfare training, and noncombatant evacuation action trainings. Additionally, MITT includes training exercises on Tinian for personnel insertion and extraction, parachute insertion, direct action (combat close quarters), direct action (breaching), and tactical (air control party), as well as humanitarian assistance and disaster relief operations.

Under the biological opinion for the MITT program regarding biosecurity, the U.S. Navy committed to several provisions to reduce the risk of BTS introduction to Tinian, including:

• Training activities will undergo a pathway risk analysis as a tool to improve programmatic efficiency while preventing the spread or introduction of BTS.

• Implementing 100% dog team inspection of all aircraft and all cargo and equipment leaving Guam for an off-island destination.

• To the maximum extent practicable, the U.S. Navy will route inbound personnel and cargo for tactical approach exercises (that require an uninterrupted flow of events) directly to CNMI training locations to avoid Guam seaports and airfields to the extent possible. If Guam cannot be avoided for tactical approaches, the U.S. Navy will work with the USFWS to identify and implement appropriate interdiction methods at the receiving port (Rota, Saipan or Tinian). Methods may include redundant inspections or other interdiction actions, such as multiple inspections or barrier use on Guam. In addition, tactical approach exercises will involve only cargo and equipment that has not originated from areas containing a BTS population or will be 100 % inspected by qualified BTS dog detector teams.

• The U.S. Navy will establish snake-free quarantine areas (barriers) as deemed necessary by the U.S. Navy and USFWS for cargo and equipment traveling from Guam to the CNMI and locations outside of the MITT action area. Barriers will be used if the volume of cargo and equipment and vehicle movement out-paces the available dog inspection capacity or BTS quarantine capacity. The snake-free quarantine areas will be subject to: (1) multiple day and

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night searches with appropriately trained interdiction dog teams, (2) snake trapping, and (3) visual inspection for snakes. Standard operating procedures will be developed based on the barrier size needed for the training event(s) and temporary barriers will be constructed and maintained in a manner that ensures the efficacy of the barrier.

• The U.S. Navy will coordinate closely with the Service and the CNMI DLNR staff on planning for training activities in the CNMI and coordinate implementation of the MITT program to identify the inspection and interdiction requirements for MITT program-related training activities.

• The U.S. Navy will utilize ongoing adaptive management to improve methods for BTS rapid response, including detection of low-density snake populations using all technologies as they become available. The U.S. Navy will annually review BTS rapid response needs with the Service to mutually determine if refined methods need to be implemented.

• Prior to each exercise that involves the movement of equipment or troops between islands, the U.S. Navy will conduct a pathway risk analysis and confirm biosecurity protocols.

In the MITT BO, we summarized our assessment of the proposed biosecurity plan by noting that there was a reasonable anticipation of higher potential for invasive species introductions to occur given the proposed increase in the frequency of military training on Tinian under the MITT program. Consequently, we expressed that additional monitoring and response capability may be needed to ensure early detection and eradication of inter-island introductions of invasive species including BTS that may be caused by MITT program-related activities. During this consultation, the Service and the U.S. Navy discussed this matter and informally agreed that such capability should be provided under a multi-agency programmatic action to implement the Regional Biosecurity Plan for Micronesia and Hawaii (RBP; U.S. Navy 2015), and subsequently the U.S. Navy hired personnel to implement U.S. Navy components of the plan (NAVFAC in litt. 2018, p. 122).

4.2.10.2 Divert Activities and Exercises (Divert)

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In 2012, the USFWS began consultation upon the US Air Force’s (USAF) proposed Divert Activities and Exercises (Divert) project EIS to analyze and make recommendations for mitigating environmental impacts associated with the proposal. The purpose of the proposed project, now in further planning stages, is to improve the existing Tinian airport and associated infrastructure in support of expanding DOD mission requirements in the region and to achieve divert capabilities in the western Pacific. More specifically, the project will establish additional divert capabilities to support and conduct current, emerging, and future USAF exercises, while ensuring the capability to meet mission requirements in the event that access to Andersen Air Force Base (AAFB) located on Guam or other western Pacific locations is limited or denied. Currently, there is no existing divert or contingency airfield on U.S. territory in the western Pacific that is designed and designated to provide strategic operational and exercise capabilities for U.S. forces when needed, or humanitarian airlift and disaster relief in times of natural or man-made disasters. On the ground, the project would consist of airport improvements including increased aircraft taxiway and parking and associated cargo pads, facilities, fencing, utilities, and roadways. Additionally as part of the project, up to eight weeks of military exercises would occur annually with cargo, tanker, or similar aircraft and needed personnel.

Of the biological opinions in place governing current military activities on Tinian, the USAF’s BO for the Divert project contains the strongest DOD commitment to stringent BTS biosecurity. The measures include many important provisions, such as direct routing of cargo to Tinian to avoid Guam seaports and airfields when possible, education of all personnel involved, BTS pathway analyses for all activities, and participation in the development and implementation of the Regional Biosecurity Plan for Micronesia and Hawaii (U.S. Navy 2014b). Most importantly, the USAF has committed to 100% redundant dog inspections for all cargo and equipment moving from Guam to Tinian, as well as the construction and operation of a permanent BTS- proof cargo quarantine containment area at the Tinian airport, which currently lacks such a facility. Additionally, the USAF has acknowledged that the planning for the Divert project’s complex training events will require a commensurate amount of planning and preparation to ensure that the operation has sufficient resources including personnel, dogs, and facilities to achieve the needed level of interdiction (USFWS 2012 p. 7-14).

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4.2.10.3 CNMI Joint Marianas Training (CJMT)

In 2015, the DOD released a draft environmental impact statement (DEIS) through the U.S. Marine Corps for a new project under the MITT program called the Commonwealth of the Northern Mariana Islands (CNMI) Joint Military Training (CJMT). According to the DEIS, the purpose of the project is to fulfill U.S. military unit level and combined-level military requirements in the Western Pacific as part of the U.S rebalancing of military forces in the Asia- Pacific region. The proposed action described in the DEIS includes the establishment of a series of live-fire and maneuver Ranges and Training Areas on the CNMI islands of Tinian and Pagan including their surrounding U.S. and international water and airspace. More specifically on Tinian, the project includes a series of construction and operational actions involving multiple land use agreements for training activities and the building and improvement of support facilities, roads and infrastructure, and training facilities. The DEIS proposed three alternatives for Tinian with minor differences, but each includes training operations proposed at four range complexes, a field artillery indirect fire range, convoy course, tracked vehicle driver’s course, tactical amphibious landing beach training, maneuver area training (light and amphibious forces), landing zone training, and airfield training. Each of the identified alternatives on Tinian would require use of the MLA, including the LBA, which has been leased back to the CNMI government for ranching and other agricultural uses. One of the alternatives also included a relocation of the International Broadcasting Bureau's (IBB) Voice of America Facility. The DEIS identified Alternative 2 as the preferred alternative for Tinian.

Regarding biosecurity for the CJMT as referenced in their 2015 DEIS for the proposed action, (U.S. Navy 2015, p. 831 under section 4.9.2.1 Avoidance and Minimization Measures), the DOD will be adhering to several policies to minimize the likelihood of BTS introduction to Tinian, including the Commander U.S. Navy Region Marianas Instruction 3500.4A (Marianas Training Manual) Appendix A: Brown Treesnake Control and Interdiction Requirements; Commander U.S. Navy Region Marianas Instruction 5090.10A (Brown Tree Snake Control and Interdiction Plan); (anticipated) final Joint Region Marianas Instruction 5090.4, which will replace Instruction 5090.10A; and 36 Wing Instruction 32-7004 (Brown Tree Snake Management); and

138 Tinian Monarch SSA Version 1.0 the DOD Transportation Regulations Chapter 505 protocols. Additionally, the DOD has committed to constructing and maintaining a self-contained biosecurity and vehicle wash-down facility on Tinian to be located at the seaport (U.S. Navy 2015, pp. 44-45 (ES-20-21)).

In their 2015 DEIS, the DOD has stated commitment to implementing 100% inspection of all outgoing aircraft and all outgoing cargo transported via ship or aircraft from Guam to Tinian with qualified quarantine officers and dog teams. Additionally, the DEIS states that redundant inspections will also be conducted beforehand on Guam within snake-free quarantine areas for all cargo transported from Guam to Tinian to include multiple day and night searches for snakes with qualified dog interdiction teams; snake trapping; and human visual inspection for BTS. The 2015 DEIS further states that the DOD will work cooperatively with the Service in the development and implementation of protocols for interdiction and control methods in accordance with recommendations in the Regional Biosecurity Plan for Micronesia and Hawaii (RBP) (previously referred to as the Micronesia Biosecurity Plan), that are determined to be applicable to CJMT activities. The RBP was developed by the U.S. Navy, NISC, USDA-APHIS, USGS- BRD, the Service, and the Smithsonian Environmental Research Center. The RBP is intended to coordinate and integrate inter-agency non-native invasive species management efforts such as outreach, species control, interdiction, rapid response, eradication, and research.

In our official comments for the CJMT, in response to both the Notice of Intent and the DEIS, we noted that the risk of BTS establishment in the CNMI posed by the proposed action, if not properly mitigated, is very high (USFWS in litt. 2013, pp. 8–9; USFWS 2015, pp. 8–9). Accordingly, we made several recommendations to mitigate the risk, including but not limited to the following:

• Collaborating with all partners to develop and implement operating instructions related to BTS interdiction and all proposed DOD operations in the CNMI to be completed prior to initiation of the proposed action.

• Routing all non-Guam based inbound personnel and cargo for the proposed exercises directly to CNMI training locations to avoid Guam. When Guam cannot be avoided,

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conducting 100% redundant dog team inspection on Guam and the receiving island for all activities.

• Using Wildlife Services personnel, inspect 100% of all Guam-based outbound cargo, aircraft, and vessels.

• Establishing and using BTS-free quarantine areas for cargo and equipment traveling from Guam to Tinian using both temporary and permanent BTS barriers depending on scale and scope of activities, and to include day and night searches, snake trapping, and visual inspection for snakes.

• Actively supporting rapid response actions related to BTS on Tinian and cooperating to develop technology, procedures, and protocols that will support rapid action for a BTS sighting as well as financial support for rapid response efforts related to DOD activities.

• Providing BTS awareness training for all military and contractor personnel.

• Due to limited availability of BTS inspectors, trained dogs, and quarantine facilities and equipment on Guam and the CNMI, coordinating closely with the all partner agencies supporting and implementing BTS control efforts within the Mariana Islands; committing to funding any increased military and civilian BTS interdiction needs in the CNMI and Guam that are directly or indirectly related to the proposed action.

• Supporting BTS research that assists in the landscape-level control of BTS on Guam, detection and eradication of BTS that might be found in the CNMI due to DOD activities, and refinement of current interdiction efforts.

The future military relocation on Guam and the CJMT are expected to greatly increase the movement and cargo off-island as well as the scale and rate of military activities on Guam and in the CNMI, including Tinian, putting additional pressure on BTS programs in each location. The DOD has expressed that it would provide the support necessary to fulfill expanded interdiction

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requirements to maintain interdiction goals if future military training and associated movement between Guam and the CNMI exceeds Wildlife Services capacity (BTSWG 2016, p. 40). Based the DOD’s past 15 years of collaborative partnership and co-funding with the BTSWG and all involved agencies to prevent the spread of BTS from Guam, we have no basis to doubt the DOD’s stated commitment to provide commensurate BTS interdiction for the CJMT.

Nevertheless, we believe the various activities and development identified for Tinian as proposed under the CJMT represent a paradigm shift and will require an order of magnitude higher funding level and effort to achieve commensurate BTS interdiction. As discussed in more detail below, the total annual cost for the current level of the overall BTS program including both interdiction and research remains approximately $7 million (BTSWG 2016, p. iv) although the funding sources for each are quite different (BTSWG 2016, pp. 32-33). Based upon the activities proposed under CJMT, we may expect a substantial increase in the annual costs of the BTS program to protect Tinian alone. This increase is a cause for concern given the budget sequestration events in recent years, coupled with problems identified in the BTSWG’s 2016 strategic plan, including a lack of dependable base programmatic funding for interdiction (p. 44) and that research funding has not kept pace with that of interdiction (p. 42). Given these uncertainties, the Service questions whether a need for increased funding to protect Tinian would be sustainably maintained without a decrease in funding for other essential components of the BTS program, including research toward large scale suppression or eradication.

Lastly, despite DOD operational requirements, efforts thus far, and expressed future commitment toward biosecurity, we remain concerned about the additional element of risk posed by the DOD’s identified need to conduct tactical operations on Tinian as part of the CJMT. According to DOD biosecurity procedures established by the MITT BO (USFWS 2015b, pp. 21, 57), the U.S. Navy will, to the maximum extent practicable, strive to bypass Guam for tactical operations to be conducted in the Mariana Islands. However when avoiding Guam is not possible, the U.S. Navy is required to utilize dog detector teams for 100% redundant inspections of all cargo, equipment, and vessels outbound to Tinian for tactical operations. For those tactical operations that are precluded from receiving the second inspection by dog detector team on Tinian (i.e., most of them due their inherent tactical nature), the U.S. Navy has agreed to conduct both of the

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100% redundant inspections on Guam under strict measures, including only during daylight hours, prior to transporting the cargo to Tinian in accordance with the recently developed 2018 Cope North Exercise BTS Control and Interdiction Plan developed by Joint Region Marianas (JRM) (JRM 2018, entire).

While the Cope North plan is a refinement of the protocol agreed upon under the MITT BO, one weakness of planned workaround is the current lack of a Wildlife Services-certified secure containment barrier on Guam that could properly safeguard cargo after BTS inspections are performed (Cravalho pers comm. 2018). Because of this facilities inadequacy on Guam and the plausible potential for operational oversight during exigently conducted tactical operations, we believe this component of the CJMT as currently described may contribute to some small additional risk and uncertainty about the future viability of the Tinian Monarch. As noted elsewhere, it is our understanding that the U.S. Navy is revising their plans for the CJMT based on public comment received on the DEIS, and although not currently available to the public, the revised plans may include additional commitments toward BTS interdiction.

4.2.11 Summary of BTS interdiction challenges and the lack of a solution for treating an incipient population

Despite major advances in risk management for BTS spread to the CNMI, the BTSWG has identified several minor (described above) and major obstacles to achieving programmatic efficacy (BTSWG 2016, pp. 17, 23). First and foremost, to prevent the transport of the BTS from Guam to the CNMI, the BTSWG believes it is imperative that all vehicles, equipment, cargo, and personal goods be subject to current BTS inspection and quarantine procedures including 100% redundant dog inspections, even though these requirements may indefinitely and substantially impact civilian and military operations in terms of cost, time, and mission accomplishment (BTSWG 2016, p. 5). Many of the challenges for the program are inherent, including for example, the high BTS density in Guam (the highest snake density in the world), the continual need for suppression by trapping around all ports on Guam, the limited effectiveness of traps for small BTS due to life stage prey preferences, and the relative ineffectiveness of trapping in the CNMI including Tinian where prey densities are extremely

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high. Obviously, balancing funding requirements for the very high costs in dollars and person hours associated with nearly all components of the interdiction program will always be challenging.

Searches by the Rapid Response Team, administered by the USGS, can be deployed from Guam and elsewhere when a BTS is reported in the CNMI, and are presently considered the primary means to confirm or limit an incipient BTS population, or possibly eradicate an established population with the use of visual searching, trapping, and detector dog teams (BTSWG 2016, pp. ii, 20, 29). However, Rapid Response Team efforts include many challenges as well, including high costs in dollars and person hours, low BTS detection probabilities (based upon approximately 25 CNMI rapid responses and actions between 2002-2016), and legal and logistical hurdles such as the need for a programmatic environmental impact statement to conduct, for example, certain searches or activities associated with the rapid response effort (BTSWG 2016, pp. 29, 69-70; Reed pers comm. 2017; Siers pers comm. 2017).

A primary challenge to effective use of any Rapid Response Team is that it is dependent on early detection, quick and accurate reporting, and effective rapid assessment decisions. Even with excellent early detection and assessment capacity, a team’s ability to respond effectively is still only as good as the resources it can bring to bear in a timely manner, which in the case of BTS rapid response, must be immediate (Stanford in litt. 2017, p. 24). As of March 2018, there are a dozen trained team members in the CNMI, and many more on Guam, who can be mobilized relatively quickly (less than one day to a few hours) for a BTS response (Barnhart pers comm. 2018). However, with only one trained team member actually based on Tinian presently, additional trained rapid response team members based on-island is an identified need for improvement to the program (Stanford in litt. 2017, p. 24; Barnhart pers comm. 2018; Clark pers comm. 2018).

As noted previously, no past rapid response effort in the CNMI has resulted in a captured BTS. This does not necessarily mean that past response efforts were ineffective or that snake sightings were not credible, but rather instead highlights the challenge of locating one or a handful of nocturnal, furtive snakes in a complex environment – assuming the sighting which triggered the

143 Tinian Monarch SSA Version 1.0 response was genuine ranging from forest blocks to port facilities to rural and urban landscapes. Additional complications arise from reliance on the limited number of trained visual searchers and dog detector teams, as well as the known limitations of current BTS trap designs in a prey- rich environment (Stanford in litt. 2017, p. 24). These challenges highlight the uncertainty of the effectiveness and the timeliness of rapid responses beyond initial efforts.

Aerial bait delivery systems have been identified in the literature and by the BTS working group members as a potential tool for controlling or even possibly eradicating BTS from large areas (Figure 32 and Figure 33). However, despite a great deal of research testing the ADS on Guam (Clark and Savarie 2012, p. 216; Dorr et al. 2016, pp. vii-x; Siers et al. 2017, pp. 1-2), the method remains costly and partially ineffective due to BTS age and size prey-preference specificity limitations, and is thus not yet ready to use for treating areas larger than 1,235 ac (500 ha) (Clark and Savarie 2012, p. 216; BTSWG 2016, pp. 18, 29-30, 38; Dorr et al. 2016, pp. vii- x). Thus, if an incipient BTS population is found on any of the islands in the CNMI, including Tinian, we may be unable to control or eradicate the population without additional refinement of the ADS. Furthermore, additional research may be needed to identify the best methodology to simultaneously suppress high-density small mammal populations found in the CNMI before success could be expected with ADS or similar BTS suppression technologies, which in turn would also having met numerous programmatic protocols (BTSWG 2016, p. 29-30; Reed pers comm. 2017; Dorr et al. 2016, pp. vii-x).

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Figure 32. Photograph of recent experimental version of the aerial bait delivery system component consisting of dead, baited mouse, delivery tube, and streamer designed to catch in the tree canopy.

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Figure 33. Photograph of recent experimental, mechanized version of the aerial bait delivery system as seen from helicopter above a test plot on Guam.

Financial support for the BTSWG and the interdiction program has increased greatly over the past decades (Figure 34). The majority of the increased support has funded Wildlife Services and their interdiction and control efforts, helping to build a program capable of achieving near 100% inspections of out-going cargo from Guam, which is at least partially responsible for the decrease in extra-limital BTS sightings during the past decade (BTSWG 2016, p. 42). However, funding for research has not kept pace with that of interdiction, and the BTSWG (2016, pp. 5, 42, 52) has noted that with status quo funding for BTS interdiction alone there will always be the persistent threat of BTS dispersal off of Guam. The BTSWG has identified several key research priorities that are necessary to advance the program including but not limited to developing a cost effective ADS. Achieving greater success with ADS and similar methods where the BTS can be suppressed across hundreds to thousands of acres will require long-term stable funding to conduct consistent research to develop improved BTS control tools, to understand the response of BTS populations to suppression, and to investigate ecological interactions between the BTS and associated species (BTSWG 2016, p. 5).

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$5,000

DOI

$4,000 DOD

APHIS

$3,000 MISC

$2,000 Funding ($ in thousands) in ($ Funding

$1,000

$0

Fiscal Year

Figure 34. Funding provided by various sources for Brown Treesnake prevention, management and research since efforts began in 1987 (from BTSWG 2016, p. 42).

4.2.12 A risk assessment model for BTS

A model has been described by Perry and Vice (2009) for forecasting the relative risk of Guam- dispersed BTS establishment at a given site, including to the main islands of the CNMI. To calculate overall risk, the model incorporated information on the likelihood of the BTS entering the transportation system, avoiding detection, surviving to arrive at another location, and establishing at the receiving end. The model also considered and balanced output with (then current) documented rates of BTS arrival at receiving sites in the CNMI and elsewhere. An intended use of the model was to prioritize interdiction efforts to focus on especially vulnerable receiving locations, including the CNMI, and to evaluate what the additional risk of BTS establishment at a second source within the CNMI (e.g., Saipan) would mean for BTS

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establishment risk elsewhere in the CNMI. Although not subsequently repeated, the model was originally designed to allow both quantitative and qualitative inputs to adjust and forecast risk under different scenarios, such as increases or decreases in interdiction effort or changes in cargo transportation rates between Guam and the CNMI.

At the time, Perry and Vice (2009, pp. 997–999) determined that the risk of BTS incursion on Tinian was high. The risk assessment for Tinian was calculated as the product of the frequency of snakes arriving on Tinian and the likelihood of an arriving snake establishing a population. Other elements that were incorporated into determining risk of incursion included the biological requirements of BTS, the likelihood of BTS survival under different transportation scenarios, the condition and types of goods shipped between Guam and the CNMI, the level of cargo by air and boat, the level of military activity and the amount of military cargo and equipment transported between Guam and the CNMI, and the current BTS interdiction level at the time. This model produced arbitrary units of risk that were binned into five categories: “low,” “medium,” “high,” “very high,” and “extreme.” Notably, the model output predicted that any incremental increase in either civilian or military cargo or military activity on Tinian—without a commensurate increase in interdiction effort—would cause the risk of BTS establishment for Tinian to rise from the “high” to the “extreme” category (Perry and Vice 2009, pp. 997–998).

Since Perry and Vice published their risk assessment in 2009, some of the factors evaluated in their model have changed. Most significantly, the BTS interdiction program on Guam has been improved due to the efforts of the DOD and other Federal agencies involved, particularly Wildlife Services and USGS (BTSWG 2016, p. iii-iv). This increase in interdiction is also reflected in level of funding. As of 2012, the level of BTS interdiction (and the overall program) costs approximately $7 million dollars annually, compared to the $5 million annual costs cited by Perry and Vice (2009, p. 994). In addition to improved interdiction on Guam, the DOD has improved the rate of inspected cargo to 99.5% and has committed to operational requirements of 100% redundant dog inspections under the biological opinions for the recent MITT and DIVERT initiatives.

Since 2009, many of the factors analyzed by Perry and Vice remain the same or similar. For example, the current level of military activity on Tinian is similarly low. After several years of

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economic downturn following the Great Recession of 2007-2010, there is reasonable indication that cargo arrivals to and civilian activity in the CNMI (although not specifically on Tinian) has increased to levels similar to those analyzed in 2009 (USGAO 2017, p. 20). As discussed above, it is a fair assessment to state that the BTS interdiction program for civilian cargo administered by the CNMI has not substantially improved since 2009 (BTSWG 2016, pp. 17, 23), although there have been facility improvements including the construction of a permanent BTS-proof barrier at Tinian’s seaport. (Note, we also stated previously that the U.S. Navy currently transports Wildlife Services inspectors to Tinian for all DOD exercises that require extra capacity for inspection).

Biologically, the other important factors including the likelihood of BTS surviving transport to Tinian and the high density of small mammal and lizard prey on Tinian most likely remain the same. Based on BTS reproductive biology, and as noted above in section 4.2.2, we more recently have better indication that it is very unlikely that a gravid BTS would be moved in transport (Vice et al. 2009, p. 198). This fact coupled with the fact that only smaller, immature snakes make it through the various barriers to be found by dogs in cargo for shipment off Guam, suggest that establishment on Tinian would require multiple incursions of immature snakes that survive, meet a mate, and successfully reproduce (Savidge et al. 2007, pp. 193-195; Richmond et al. 2014 p. 1). Such a scenario is not implausible, but the low probability does not lend weight to the risk.

One flaw identified by Perry and Vice (2009, p. 995) was their inability to include the volume of cargo by private boat as a factor in their analysis, but they noted that it was not possible to obtain this information. To date, uninspected cargo between Guam and the CNMI and to Tinian is still known to occur (Gosnell pers comm. 2017; Clark pers comm. 2018), and to be certain, only adds some level of non-quantifiable risk of BTS establishing on Tinian both currently and in the future.

We believe the basis of the Perry and Vice (2009, entire) risk analysis model is still largely accurate. However, we assess the current risk of BTS establishing on Tinian closer to a low to moderate level, given the $2 million increase in annual BTS program funding, interdiction improvements on Guam since 2009, and the fact that we now know that there is a lower risk of large adult snakes and gravid females leaving Guam in the transportation system (Vice et al.

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2009, p. 198; Richmond et al. 2014, p. 1). Also as described below in more detail in section 4.3, the increase in military activities planned for Tinian may not appreciably increase BTS risk given the DOD’s requirements under the MITT BO for commensurate interdiction including 100% redundant dog inspections. The largest uncertainty surrounding the risk analysis concerns the Service’s longer term historical perspective about the CNMI BTS program, and whether recently observed improvements can be maintained consistently and even increased to be commensurate with the anticipated future increases in civilian cargo. Additionally, uninspected cargo arriving to Tinian from Guam is still an important concern given all unchanged variables including BTS biology, the high prey densities in the CNMI, the ideally suitable tropical environment, and the proximity of the CNMI to Guam.

4.2.13 BTS summary

The inadvertent introduction of the invasive BTS to Guam in the late 1940s rapidly devastated the island’s native fauna. Since then, although the BTS has not established on Tinian or any other island (as far as we know), BTS have periodically been observed and at times intercepted at various locations outside of its native and known non-native range. Currently, much of the civilian and military cargo brought to Tinian is shipped from Guam, some indirectly through Saipan, and consequently, the risk of inadvertent BTS introduction to Tinian remains a possibility. Should establishment of BTS occur on Tinian, the likelihood of detecting, let alone eradicating an incipient BTS population is presently very uncertain given the tools currently available and their associated challenges.

Although imperfect, the Perry and Vice model described the risk of BTS establishment on Tinian as high and concluded that BTS introduction on Saipan would elevate that risk to extreme (Perry and Vice 2009 entire). While we believe many of the factors analyzed by Perry and Vice remain relevant and similar in scope and scale, the level of civilian and military BTS interdiction on Guam is currently better funded and significantly improved since 2009. In particular, nearly all DOD cargo receives inspection prior to departure from Guam and the DOD has expressed commitment to 100% redundant dog inspections for all its cargo between Guam and Tinian. Consequently, we believe the current risk of BTS establishment to Tinian is low to moderate.

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Increased DOD activity such as that described in the CJMT DEIS involving the direct movement of materials and equipment from Guam to Tinian (see section 4.3 below) and during tactical operations as described in the DIVERT and MITT biological opinions (USFWS 2012, entire; USFWS 2015, pp. 21, 57-58) has significant potential for increasing the risk of the BTS introduction to Tinian. However, the DOD continues to express commitment for interdiction commensurate to all activities including 100% redundant dog inspections. We believe the increases in DOD activity anticipated under CJMT and the associated potential risk of transporting BTS to Tinian can be substantially mitigated to a moderate level by commensurate DOD interdiction efforts, if coupled with the measures we have identified in our future scenarios analysis (see Section 5.2.5) including but not limited to improved biosecurity on Tinian, different administration of the CNMI BTS program, and an improved rapid response program that includes the appropriate operational measures in place on each island including Tinian (Perry and Vice 2009, p. 998; BTSWG 2016, pp. 1, 5-6; Campbell pers comm. 2017, p. 2).

4.3 Future Military Activities – CNMI Joint Military Training

The DOD, through the U.S. Marine Corps, has proposed to establish live-fire Range Training Areas within the CNMI on the islands of Tinian and Pagan to fulfill training requirements in the Western Pacific as part of the rebalancing of U.S. military forces in the Asia-Pacific region. To meet the training needs identified by its internal assessments, the U.S. Navy has proposed actions on Tinian including a series of construction and operational projects involving land-use agreements, construction and improvements including support facilities and infrastructure construction and training facilities, and training operations (U.S. Navy 2015, entire). The DEIS included three alternatives for Tinian, each with minor differences in terms of overall footprint and forest impact. All three alternatives include training operations proposed at four range complexes (Figure 35), a field artillery indirect fire range, convoy course, tracked vehicle driver’s course, tactical amphibious landing beach training, maneuver area training (light and amphibious forces), landing zone training, and airfield training. At the time, Alternative 2 was identified by the U.S. Navy as the preferred alternative. As noted previously, it is our understanding that the U.S. Navy is revising the EIS based on public comment received on the

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CJMT DEIS. Because the revisions to the EIS are not currently available to the public, we have based our analysis upon the 2015 DEIS.

4.3.1 Land Alteration and Potential Displacement of the Tinian Monarch

According to Alternative 2 (U.S. Navy 2015, p. 4-221), an estimated 1,800 ac (728 ha) of forest habitat would be developed (removed), which represents 10.6% of the Monarch’s currently available forested habitat (Figure 35). Thus, we expect Tinian Monarch distribution to be reduced in the northern two-thirds of Tinian due to increased military development and activity within the Military Lease Area as described by the 2015 CJMT DEIS. Additionally, the U.S. Navy DEIS estimated that approximately 7,200 Tinian Monarchs, or 8% of the population, would potentially be displaced permanently by forest habitat loss from the project’s developed footprint, including 29 Monarchs from 6 ac (1.62 ha) of native forest; 3,828 Monarchs from approximately 1,060 ac (429 ha) of secondary-mixed forest (including herbaceous-scrub as described in the CJMT DEIS); and 3,373 individuals from 817 ac (330 ha) of tangantangan forest (U.S. Navy 2015, pp. 4-220-4-221). These estimates correspond closely with our own analysis of Tinian monarch density in each forest habitat, as well as the potential impact of forest habitat loss due to land alteration and development associated with the CJMT (Amidon in litt. 2017, entire).

As noted in Section 2.3.5, above, reduction in abundance resulting from development and displacement of Monarchs would be primarily attributed to the reduced reproductive success of individuals that would lose their breeding territory to the development and possibly from mortality of adults immediately displaced. In considering the possible impacts of the CJMT for example, we assessed only the actual footprint of the development, meaning those areas where forest habitat would become permanently or indefinitely unavailable due to paving, clearing, etc. The assessment did not attempt to measure the possibility of displacement from construction activity while the various ranges and infrastructure are developed, or from activities on the ranges after the project is completed. Additionally, as noted elsewhere in this discussion, we expect that the full decline in Monarch abundance may not occur during the period of the proposed CJMT development, but may lag behind as the island-wide population stabilizes over the ensuing years.

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Figure 35. Footprint of planned military development defined under Alternative 2 in the Commonwealth of the Northern Mariana Islands Joint Military Training.

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4.3.2 Fragmentation

We believe the Tinian Monarch represents a single, interbreeding population because there is little to no discontinuity among individuals from geographic or other barriers. However, given that increased habitat fragmentation and patchiness is suspected to be deleterious to some forest birds (VanderWerf et al. 2001, pp. 13, 15; VanderWerf 2004, p. 770), we conducted our own simple analysis of the effect of the CJMT on Tinian forest habitat fragmentation. We did so by overlaying spatial information for vegetation on Tinian with the proposed footprint for development under the CJMT DEIS. Our results indicate that there are currently 421 forest patches on the island, delineated as distinct areas of forest cover separated from adjacent areas of forest cover by areas of non-forest cover at least 33 ft (10 m) in width (the average width of road and road margins on Tinian). If the CJMT DEIS Alternative 2 is developed as proposed, the number of forest habitat patches will increase from 421 to 1,175 patches (Amidon in litt. 2017, entire), see also Figure 35. While we lack a means to measure the result of this outcome from the CJMT, it is plausible that the (threefold) increase in the number of habitat patches on Tinian due to the CJMT, could negatively impact the number of usable breeding territories available to the Monarch by fragmenting existing territories (Robinson et al. 1995, p. 1,987).

4.3.3 Land Alteration Mitigation

To offset the CJMT DEIS’ impacts to Tinian Monarch habitat, the DOD has proposed, but not committed, to possible mitigation, including restoration of an equal amount of non-native forest to offset the loss of six acres of native forest, possible designation of alternate sites to replace the proposed loss of the FAA Mitigation Conservation Area, and creation of a forest–bird monitoring plan, among other potential mitigation efforts. However, in the Service’s official comments on the DEIS, it was the Service’s assessment that none of the potential mitigation would offset the impacts of proposed habitat loss under the CJMT DEIS (USFWS in litt. 2015). In addition to concern about the lack of commitment for these proposals as described in the CJMT DEIS, the Service does not believe there is sufficient evidence to suggest the proposed measures would actually offset the removal of 10% of the Monarch’s habitat. For example, there are no examples of successful native forest recovery in the Mariana Islands, and no precedent for conservation management actions that benefit the Tinian Monarch, which means that

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replacement sites for the FAA Mitigation Conservation Area or use of a forest bird monitoring plan would be likely inadequate to counter the actual loss of forested habitat. For these reasons, we did not carry forward the proposed mitigation efforts into our analysis of future scenarios of the Monarch’s viability. It is, however, important to note that U.S. Navy is apparently revising the EIS and ultimately, the mitigation for impacts may be greater or less than what was proposed in the 2015 DEIS and upon which we are basing our current analysis.

Additionally, according to the DOD, the U.S. Navy is, in conjunction with future plans for the CJMT, awaiting approval to develop a candidate conservation agreement for the Monarch which would include management actions that may address the various potential impacts to the species as a result of the action (NAVFAC 2018, p. 46). However, at this time we currently do not have any information on what conservation measures would be included in this document and cannot therefore include those measures in this assessment.

4.3.4 The Future of Cattle Ranching Under CJMT

As noted in Chapter 3, the DOD currently subleases a portion of the LBA (which it leases from the CNMI government) back to Tinian residents for cattle ranching and other purposes. According to the DEIS, the total agriculture and grazing area was estimated at 2,552 ac (1,032 ha); see Figure 36. The DEIS noted that while grazing and agricultural permits issued by the Department of Public Lands had expired, most of the ranches were still occupied and operating under arrangements for a month-to-month lease. In January 2015, the lease was extended until the summer of 2016 (U.S. Navy 2015, pp. 3-81, 3-89.

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Figure 36. Map showing existing land uses on Tinian including areas previously under ranching permit within the Leaseback Area (from the CJMT DEIS, U.S. Navy 2015, p. 3-86, Figure 37-5).

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All three alternatives described in the 2015 DEIS for the CJMT included substantial changes to portions of the LBA including many changes to areas currently used for ranching (Figure 37 and Figure 38) that would then be restricted or precluded entirely due to construction initially and subsequently by military exercises and associated activities. According to what has been stated to the public about the matter (Camacho 2015, p. 1; DuPoncheel pers. comm. 2017), the U.S. Navy intends to allow ranching to continue within the LBA without a reduction in individual permittee acreages and would relocate ranches if necessary to achieve that goal. Given this stated intent to allow continued ranching, and of course, depending upon the final revised EIS for the CJMT and what the DOD decides is feasible, we believe three outcomes are plausible: (1) the U.S. Navy may allow some or most of the leases to remain intact and move only those ranches deemed necessary due construction or military exercises; (2) the military may allow most or all of the ranches to continue operating but within different areas of the LBA, potentially causing additional forested lands to be cleared if any are relocated to forested lands that must be converted to pasture; or (3) the military may largely curtail or reduce the amount of ranching acreage in the LBA, resulting in most of or all ranches moving to civilian areas in the southern one-third of the island.

Under the first scenario, the U.S. Navy would have to determine that the military development and activities proposed under the CJMT are more compatible with ranching and grazing than what has been described in the DEIS (U.S. Navy 2015, p. 4-165). If the second scenario occurred and ranches were relocated to forested areas that require some level of conversion to pasture, additional forested habitat of the Tinian Monarch may be destroyed or impacted. We consider the third scenario the least likely, given the military’s stated desire to work with the CNMI government and the civilian population on Tinian (Camacho 2015, p. 1). If however, the U.S. Navy determined that a majority of ranching could not continue within the LBA, a possible result could include additional pressures on the civilian-controlled lands in the southern third of the island (USFWS in litt. 2015, p. 8), where the larger portion of the island’s limestone forest remains, at 966 ac (391 ha), or 71%. Ultimately, if ranching acreage is not relocated onto other existing pasture lands either within the LBA or in southern Tinian, there is reasonable potential

157 Tinian Monarch SSA Version 1.0 for additional forest habitat to be impacted if ranching is continued at the same level or expanded.

Figure 37. Map showing cattle ranch lands in 2013 on Tinian both within the Military Leaseback Area and on private lands to the south of the military lease area. (from “Beef Cattle Herd Survey, 2013 Island of Tinian, Commonwealth of the Northern Mariana Islands,” Northern Marianas College, Cooperative Research, Extension and Education Service).

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Figure 38. Map showing 2014 agricultural lease areas and proposed relocation of agricultural lease areas within the Military Lease Area under the Commonwealth of the Northern Mariana Islands Joint Military Training.

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All three of these outcomes regarding the fate of ranching in the LBA create some potential for forest loss that is not addressed in any detail in the CJMT DEIS. Accordingly and without additional information about their fate, we could not account for these outcomes in either the military or the civilian projections discussed in section 3.2.1 “Forest Habitat Changes Due to Human Activity.” We are currently unable to predict whether ranches will stay in the MLA or be moved, or how many acres will be affected. Additionally, if ranches are moved from one location to another, there is likely some additional risk of cattle becoming feral, either as a result of their escaping from captivity during transport or due to the inadequacy of their temporary housing.

4.3.5 CJMT and Increased Wildfire Risk

Lastly, we expect some unknown amount of habitat impact from the additional risk of wildfire as a result of increased military activity planned under the CJMT DEIS. The U.S Navy has stated commitment for mitigating that risk and according to the CJMT DEIS (U.S. Navy 2015, pp. 2- 76; 4-191; 4-209), there are plans to develop a wildfire management plan for the action (see additional discussion below within this section).

To determine the potential for wildfire risk on Tinian in our scenarios, we relied on a white paper report by Dawn Bruns, fire behavior and weather specialist with the Service, entitled “Training- Related Wildfire Threat on Tinian and Pagan, CNMI” (2017). In the analysis, National Weather Service assessments of drought, 1-hour fuel moisture, and wind speed data from the Saipan weather station from 1989 through April 2017 were used because it is the closest existing weather station to Tinian. The analysis focused upon the fire risk associated with projected live fire training proposed under the CJMT, including TOW missiles, tracers, and live rounds from grenade launchers, mortars, artillery, and aerial and naval gunfire. Based upon published surface danger zones delineating the possible area within which each round will land (Beavers et al 1999 Appendix 1; USFWS in litt. 2007 pp. 88 – 95), the analysis assumed that these munitions have the potential to ignite wildfires outside their respective Tinian training range footprints because the areas where live rounds or rockets (even if inert) may land or ricochet appear to be larger than the training range footprints.

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Potential fire size resulting from the incendiary impacts of the various munitions under the range of possible seasonal moisture and wind conditions on Tinian was estimated using appropriate modeling programs including the CONTAIN module of BEHAVE Plus (USFS 2017 (https://www.frames.gov/partner-sites/behaveplus/software-manuals/)). This analysis used fuel models in the LANDFIRE (2013) fuel model maps (iaz82_120fb40 (z82_120FBFM40\Grid\) (https://www.landfire.gov/islands_download.php), of which the two most dominant fuel model maps for Tinian are the TU2 for tangantangan (162, Scott and Burgan 2005 p. 52, https://www.fs.fed.us/rm/pubs/rmrs_gtr153.pdf) and TU5 (165, for forest, Scott and Burgan 2005 p. 55). Lastly, the analysis examined the appropriate level of fire suppression needed based upon the proposed munitions, terrain, and range of drought and fire weather conditions, for which input was obtained from the United States Forest Service, Fire and Aviation Management Pacific Southwest Region (T. Mahoney, pers. comm. 2017).

In our analysis of the potential for wildfire risk on Tinian resulting from the operations of the CJMT (Bruns in litt. 2017, entire), we found that there was substantial additional risk of forest habitat igniting and burning within the MLA if live-fire training activities are not conducted in accordance with seasonality. For example, if training were restricted to periods of the wet season when Keetch-Byram Drought Index is 300 or lower, the likelihood of training-related wildfire ignition and fire spread potential would be low and the necessary level of fire suppression response could be minimal. However, if long-range weapons with the potential to ignite fires outside training range footprints are permitted during the dry season (generally from about March 1 through June when the Keetch-Byram Drought Index is above 600) and fire suppression staffing is not sufficient to contain wildfires (our assessment from the analysis), fire frequency in the MLA could be high with the result that forest vegetation could be converted to grass with corresponding impacts to the Tinian Monarch (Bruns in litt. 2017, pp. 1-2).

The DOD has previously addressed fire risk in great detail regarding its prior plans governing DOD actions and exercises in the CNMI. For example, in their 2010 final EIS for the Guam and CNMI Military Relocation, the U.S. Navy (2010, p. 102) identified increased fire potential from their proposed firing range operations on Tinian and stated that wildfire can result in direct effects to all wildlife through mortality from smoke inhalation or direct mortality. According to the EIS (U.S. Navy 2010, p. 102), grass fires are regular occurrences on Tinian with greater

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danger during the dry season. The EIS further cited data from the 1997 Tinian INRMP that showed that the highest fire risk exists throughout the driest months of the dry season May through July) for normal, non-El Nino years (El Nino year dry seasons may be longer). According to the EIS, 200 or more acres may burn each year during this short time frame. The EIS also cautioned that “the alteration or removal of habitats by fire could reduce food sources or prevent or inhibit breeding and create competition for feeding and sheltering, particularly for species that establish discrete territories” with significant impacts to those species (U.S. Navy 2010, p. 102). However, the EIS noted that a wildfire management plan would be developed as a part of a larger management plan governing the proposed range with the goal that impacts would be less than significant.

In their 2014 biological assessment for the proposed Mariana Islands Training and Testing Program, the U.S. Navy noted that as of 2014, no wildfire had been ignited from MIRC training activities on Tinian or other DOD lands in the Mariana Islands (USFWS 2015, p. 63). The BA stated that to further minimize risk and augment military fire response efforts, the Tinian Fire Department maintains a 300-gallon pump truck and fire crew to respond to wildland fires, as well as a 750-gallon pump truck and crew in San Jose to provide fire service for southern Tinian and backup Crash-Fire-Rescue support to the West Field area. According to the BA, the U.S. Navy would request the use of Tinian Fire Department assets for major exercises as part of the MITT program and would control any military related fires prior to the loss of any wetland or native forest habitat and control losses of tangantangan habitat to a minimum of 5 ac (2 ha) (USFWS 2015, p. 63).

The CJMT DEIS (U.S. Navy 2015, pp. 2-76; 4-191; 4-209) outlines plans for managing the risk of wildfire associated with the CJMT. While the DEIS acknowledges the additional fire risk in conducting live-fire training on Tinian, it refers to a wildfire management plan that will be put into place to govern the activities connected to wildfire, including but not limited to live-fire training. While the fire management plan itself was not included in the DEIS, we briefly discuss below the elements of the plan that were outlined in the DEIS.

Citing the Service (USFWS 2009), the CJMT DEIS noted that native habitats on Tinian are adapted to a humid, tropical climate absent of fire. The DEIS also states that fire can result in

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direct effects to vegetation by killing or damaging individual plants, or through indirect effects such as increased erosion, facilitating invasion by non-native species, and altering wildlife habitat by reducing food resources, breeding habitat, and shelter.

According to the DEIS (U.S. Navy 2015, p. 2-76; (Section 4.9.2 “Resource Management Measures: 4.9.2.1 Avoidance and Minimization Measures,” p. 4–191)), the U.S. Navy would prepare a fire management plan specific to proposed CJMT activities prior to initiation of any live-fire training on Tinian. The DEIS states that the plan would “address the preventative and immediate actions required for fire hazards connected with range and training area (RTA) training,” and the plan would identify water and labor resources necessary to ensure safe training and protection of public safety and property. The DEIS identified other fire preventative measures that would be components of the fire plan, including vegetation management and 90-ft (30-m) firebreak creation in and around the High Hazard Impact Area, locating water trucks and hydrants at the base camp and Munitions Storage Area, and prescribed burns to control vegetation within the High Hazard Impact Area.

Although we are unaware of any past wildfires on Tinian resulting from U.S. military training activities and the U.S. Navy has not reported any such occurrences to date, we agree with the expectation expressed in the CJMT DEIS that risk of wildfire would increase incrementally as a result of the proposed live-fire and vehicle maneuvering operations (U.S. Navy 2015, p. 4–210). We also concur that the wildfire management plan components briefly outlined in the DEIS are necessary to minimize the possibility of fire resulting from the various proposed activities. However, without additional details about the plans, it is not possible to evaluate the adequacy of the plan beyond the concerns raised here, especially in relation to the timing of proposed live-fire training on Tinian.

Our own basic analysis suggests that there is substantial additional risk of forest habitat igniting and burning within the MLA if live-fire training activities are not conducted in accordance with seasonality. With substantially expanded plans for live-fire training and various ranges and infrastructure on Tinian per the CJMT (U.S. Navy 2015, entire), we are concerned about the additional increased risk of impacts to forest habitat as a result of wildfire. The DEIS for the CJMT briefly outlines plans to implement a wildfire management plan as a part of the operation,

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and yet our own analysis suggests there is substantial additional risk of wildfire that may impact the Tinian Monarch directly from mortality and indirectly through displacement following loss of forest habitat that is burned.

4.4 Future Civilian Activities

The Tinian government has stated an interest in pursuing additional civilian projects on the island including resort and infrastructure development to improve the economy and job prospects for its inhabitants (CNMI 2015, p.13, 62–63; Figure 39). However, civilian development intentions in the CNMI can be unclear, and information about planned developments on Tinian can be difficult to obtain. The documents we are relying upon, therefore, include the 2015 DEIS and the CNMI government comments upon the DEIS. The CNMI government reacted to the DEIS negatively, indicating that the military’s plans would impede their ability to develop resorts, possibly leaving the status of their development plans uncertain (CNMI 2015, p.13, 62– 63). Additionally, some projects occur with little advance notice as exemplified by a recent civilian development project, the Altercity resort (formerly the Plumeria resort), which was begun in 2016 (Willsey in litt. 2016), apparently without proper documentation such as a project- specific environmental assessment or and approval for forest clearance (see additional discussion below in this same section).

Despite the CNMI government’s assertion that military expansion on Tinian may negatively impact civilian development and activity (CNMI 2015, p.13, 62–63), the Service believes that any number of civilian development activities may occur. One possibility is that if the CJMT DEIS expansion on Tinian occurs as described in the 2015 DEIS, civilian development may increase as a result of the military community’s need for support and the resulting money entering the economy, similar to areas throughout the U.S. where civilian communities grow adjacent to military installations. It is also possible that increased military development and activity on Tinian will negatively impact tourism and cause islands residents to leave as the CNMI government predicts. Additionally, it is possible that the CJMT project may not occur as described or at all. In understanding our assessment of the future scenarios, it is important to recall that Tinian’s civilian population currently utilizes the MLA for some activities including agricultural uses such as ranching, but otherwise entirely resides in and is largely confined

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economically to the southern third of the island, which is home to 48% of the Tinian Monarch population, supports 44% of its habitat, and contains 71% of the native forest on Tinian.

In 2016, as noted above in this same section, approximately 371 ac (150 ha) of land was cleared without authorization for a pending development project (Figure 40 and Figure 41), currently called the Altercity Resort. Construction at the site is now allegedly on-hold and with an uncertain completion date according to the project’s website (http://www.altercitygroup.com/en/col.jsp?id=112). With this recent project in mind as well as those identified by the CNMI government (CNMI 2015, pp. 4-6, 18), including the West San Jose Homestead (Figure 41) begun in 2014 (U.S. Navy 2015 pp. 3-90, 5-3), the Waste Transfer Station begun in 2017, and future plans for homesteads in the Carolinas region (http://www.dpl.gov.mp/tinian-village-maps/), we forecasted several projections for our future scenarios analysis (Section 5.2).

This future scenarios analysis assumes that up to six civilian projects could occur at the same land-use scope as the Altercity project intermittently over the next 16 to 66 years, time periods which were identified based on the remaining time for the military’s lease of the MLA and including its option for renewal, respectively. In other words, we anticipate some loss of habitat due to civilian development over the next 16 years, and forecasted for either one project 350 ac in size or three projects comprising a total of 1,050 ac (350 ac / per). Additionally, during the potential renewal of the military’s lease for a subsequent 50 years, we are projecting that an additional three projects of approximately the same size (1,050 ac (350 ac / per)) could plausibly occur.

Over the entire 66-year time period, if all six predicted civilian projects were developed, they would in theory remove approximately 2,100 ac (890 ha) of habitat (13% of the Monarch habitat currently available) and permanently displace 8,400 Tinian Monarchs (9.3% of the current estimated population) using the U.S. Navy’s density estimate of 3.8 Monarchs per acre (9.4 per ha) of forest habitat lost (U.S. Navy 2015, p. 4-221).

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Figure 39. 2017 photograph of billboard advertising a proposed casino resort (currently on hold) to be located near the harbor in San Jose (photograph by Mike Richardson).

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Figure 40. 2017 photographs (looking southwest) showing portions of the areas cleared in 2016 for the Altercity Resort (photographs by Mike Richardson).

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Figure 41. Map of Tinian showing the footprint for two recent civilian development projects in the southern third of the island.

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Chapter Five: Future Scenarios 5.1 Overview

The Service has conducted this Species Status Assessment using the best available scientific and commercial data to determine the viability of the Tinian Monarch. Here, we combine our understanding of the species’ ecology—including its needs at the individual and the species levels as well as its resiliency, representation, and redundancy—with its current condition and the factors influencing its viability. We assess the Monarch’s future viability under a series of five scenarios that we consider plausible based on what is known about current and future development, risk of wildfire, and the risk of BTS establishment on Tinian.

Under these five plausible scenarios, we incorporated both military development (based on the U.S. Air Force’s DIVERT BO and the U.S. Navy’s 2015 DEIS for the CJMT) and future civilian development projections (according to plans outlined by the CNMI and reasonable hypothetical projections based on past and current rates of development) occurring at various rates over the next 16 and 66 years (the remaining time period covered by the U.S. Navy’s current lease and its renewal option). Additionally, we considered the probable changes in risk of BTS establishment and wildfire occurrence under the five scenarios (Table 16). Analysis of the five scenarios allowed us to consider the possibility and probability of the extent to which forest habitat may be removed or otherwise altered by development and associated human activities. Analyzing the five scenarios also allowed us to assess various outcomes including for example, the mitigated / unmitigated risk of wildfire from military training activities and BTS establishment on Tinian. Because it is not possible for us to reasonably predict the effects of some impacts or actions on the Tinian Monarch such as grazing or mitigation, we did not incorporate those factors into our analysis even though they are discussed previously in this document.

Due to the uncertainty surrounding the scope and timing of future civilian development on the island, we wanted to include a wider range of possible outcomes in our analysis. We therefore further subdivided Scenarios that included civilian development (One, Three, Four, and Five) into two potential outcomes for development during the remaining 16 years of the first lease agreement between the U.S. Navy and the CNMI government: the first outcome includes a single civilian development project within the next 16 years while a second outcome envisions three

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civilian projects over the next 16 years. For the second lease period of 50 years (2033-2083), we simply projected three additional civilian projects and did not attempt to forecast for different outcomes.

Scenario One envisions only civilian development and commensurate increases in risk of wildfire and BTS establishment, but no military development nor improvements to the civilian BTS interdiction program and facilities. As outlined above, civilian development estimates were hypothetical projections based on actual civilian land use development occurring on Tinian or that has occurred during the past approximately ten years. Scenario Two envisions only military development and commensurate increases in risks of wildfire and BTS establishment, but no civilian development nor improvements to the civilian BTS interdiction program and facilities. Under Scenarios Three and Four, both military and civilian development are projected with similar increases in wildfire risk, but different levels of civilian BTS interdiction: Scenario Three does not include improvements to the civilian BTS interdiction program and facilities, while Scenario Four envisions an improved civilian BTS interdiction program including Wildlife Services-certified quarantine and containment facilities at all Saipan and Tinian air and sea ports according to the recommendations of the BTSWG (Table 16). Scenario Five is the same as Scenario Four, but includes “additional safeguards” identified by brown treesnake interdiction experts as necessary to further reduce the risk of BTS incursion to Tinian.

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Table 16. Outline of scenarios evaluated for the future condition of the Tinian Monarch. No military development, some increase in civilian development, and no Scenario One improvements to civilian BTS interdiction program and facilities.

Planned military development per the CJMT DEIS Alternative 2, no increase in Scenario Two civilian development, and no improvements to civilian BTS interdiction program and facilities.

Planned military development per the CJMT DEIS, some increase in civilian Scenario Three development, and no improvements to civilian BTS interdiction program and facilities.

Planned military development per the CJMT DEIS, some increase in civilian Scenario Four development, and improvements to the civilian BTS interdiction program and facilities.

Planned military development per the CJMT DEIS, some increase in civilian Scenario Five development, improvements to the civilian BTS interdiction program and facilities, and ‘additional safeguards’ for the BTS program.

5.2 Tinian Monarch condition under each scenario

The following discussion summarizes the condition of the Tinian Monarch under each scenario as summarized in Table 17.

5.2.1 Scenario One

Under this scenario, we forecasted only for the occurrence of civilian development in Southern Tinian, with approximately 350–1,050 ac of forest habitat (2.07-6.21% of all forest habitat island-wide) being developed in the next 16 years (by 2033) and a total of 2,200 ac of forest habitat (13.02%) being developed within 66 years (by 2083). Because most of the remaining native forest occurs along ridges and cliffs, the majority of the forest habitat development projected under this scenario would likely be comprised of tangantangan and mixed-secondary forest. Development of forest habitat would displace both breeding pairs and individuals, resulting in Tinian Monarch abundance decline over time of approximately 1,330–4,200 individuals (1.46-4.63% of the population according to 2014 estimates) during the next 16 years and by a total of approximately 8,400 individuals (9.26%) within 66 years. Under this scenario, we also expect some additional wildfire risk as a result of increased civilian activity in southern

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Tinian. Impacts from this increased wildfire risk would also displace Monarchs followed by an eventual decline in the species’ abundance.

Since the reduction in abundance from development of habitat and wildfires may be primarily attributed to reduced reproductive success of individuals that lose their breeding territory, the decline in abundance may not occur immediately but over a period of several years. A decline in the abundance of Monarchs would reduce the resiliency of the species. However, because the development projects and risk of wildfire are primarily forecasted to occur in the southern portion of the island, the potential for impacts to the species abundance would be restricted to that portion of the species’ range. More importantly, the island-wide distribution of the species would remain relatively unchanged, with Monarchs persisting throughout the island’s remaining forested habitat albeit in lower abundance. Maintaining the species’ relatively wide distribution on the island will help maintain its ability to withstand stochastic events and its overall resiliency.

Under Scenario One, we assume no improvements to the civilian BTS interdiction program and facilities. Consequently, the risk of BTS establishment would either remain at a low to moderate level of risk (our current assessment of BTS risk (see Section 4.2.13)) or increase to a moderate to high level of risk, due to some increase in the amount of incoming cargo for civilian development and activities. Some portion of this cargo would likely come from Guam where BTS is established (even if indirectly through Saipan). Establishment of BTS on Tinian would likely result in an extirpation of Monarchs throughout its range on the island and would substantially reduce the species’ resiliency and render the Monarch at an increased risk of extinction.

5.2.2 Scenario Two

Under this scenario, approximately 1,800 ac (728 ha) of forest habitat (10.65% of all forest habitat on Tinian) would be developed for the CJMT by the military within the MLA during the next 16 years (by 2033). This scenario does not include a projection for substantial civilian development nor any substantial development at all (military or civilian) during a possible second lease term of 50 years beginning in 2033 and ending in 2083. The vast majority of the forest habitat development projected under this scenario would occur in tangantangan forest 817

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ac (330 ha) and mixed-secondary forest (including some herbaceous scrub) 1,060 ac (429 ha) with development of only 6 ac (1.62 ha) of native forest. Development of forest habitat would occur within the next 16 years remaining within the current lease ending in 2033, and would cause displacement of both breeding pairs and individual Tinian Monarchs and decline in the overall abundance over time by approximately 7,200 individuals (approximately 7.94% of the population according to 2013 estimates). Under this scenario, we also expect substantial additional wildfire risk as a result of the activities forecast under the plans described in the CJMT DEIS. Impacts from increased wildfire risk would also displace Monarchs followed by an eventual decline in the species’ abundance. Similar to the impacts from civilian development described under Scenario One, the reduction in Monarch abundance may be primarily attributed to reduced reproductive success of individuals that lose their breeding territory to the development footprint or wildfire.

Since the reduction in abundance from development of habitat and wildfires may be primarily attributed to reduced reproductive success of individuals that lose their breeding territory, the decline in abundance may not occur immediately but over a period of several years. Furthermore, if civilian activities, particularly ranching and agriculture, are restricted to the southern portion of the island while military activities simultaneously increase within the MLA, we may expect some additional potential for impact to the species’ distribution and abundance island-wide, particularly in southern Tinian. These effects upon distribution and abundance would result in a reduction in the overall resiliency of the Tinian Monarch.

Under Scenario Two, we assume no improvements to the civilian BTS interdiction program and facilities. Additionally, despite current DOD protocol requiring 100% redundant BTS inspections by dog detector teams, the risk of BTS establishment would increase from a low to moderate level (our current assessment of BTS risk (see Section 4.2.13)) to a moderate to high level of risk due to a substantial increase in incoming cargo as projected by the military for CJMT development and activities (CJMT DEIS). Much of this cargo will likely originate from Guam where BTS is established (even if indirectly through Saipan). Establishment of BTS on Tinian would likely result in extirpation of Monarchs throughout its range on the island and would substantially reduce the species’ resiliency and render the Monarch at an increased risk of extinction.

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5.2.3 Scenario Three

Under this scenario, both civilian and military development would occur to the extent described under Scenario One and Scenario Two, respectively. Under these conditions, approximately 2,150-2,850 ac of forest habitat (12.77-14.79% of all forest habitat) would be developed within 16-years (by 2033) and a total of approximately 3,900 ac of forest habitat (23.67%) would be lost within 66 years (by 2083). As noted above in section 5.2.2, based upon the 2015 CJMT DEIS, the majority of the forest habitat planned (known) for development under this scenario would likely be comprised of tangantangan and mixed-secondary forest. This development of forest habitat would cause displacement of breeding pairs and individuals, resulting in a decline in Tinian Monarch abundance over time by approximately 8,530–11,400 individuals (9.41-12.57% of the population according to 2014 estimates) within 16 years and by a total of approximately 15,600 individuals (17.21%) within 66 years. As with Scenario One and Two, we predict this scenario would include substantial additional risk of wildfire due to increases in both civilian and military activities, which could similarly displace individuals and lead to some decline in Monarch abundance.

Since the reduction in abundance from development of habitat and wildfires may be primarily attributed to reduced reproductive success of individuals that lose their breeding territory, the decline in abundance may not occur immediately but over a period of several years. A decline in the abundance of Monarchs would reduce the resiliency of the species. Furthermore, if civilian activities, particularly ranching and agriculture, are restricted to the southern portion of the island while military activities simultaneously increase within the MLA, we may expect some additional potential for impact to the species’ distribution and abundance island-wide, particularly in southern Tinian. These effects upon distribution and abundance would result in a reduction in the overall resiliency of the Tinian Monarch.

Under Scenario Three, we assume no improvements to the civilian BTS interdiction program and facilities. Additionally, despite current DOD protocol requiring 100% redundant BTS inspections by dog detector teams, the risk of BTS establishment would increase from a low to moderate level (our current assessment of BTS risk (see Section 4.2.13)) to a high to extreme level of risk, due to a substantial increase in the amount of incoming cargo as projected by the

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military for CJMT development and activities as well as for civilian development projects and activities. Much of this cargo will likely originate from Guam where BTS is established (even if indirectly through Saipan). Establishment of BTS on Tinian would likely result in extirpation of Monarchs throughout its range on the island and would substantially reduce the species’ resiliency and render the Monarch at an increased risk of extinction.

5.2.4 Scenario Four

Under this fourth scenario, both civilian and military development are projected and the amount of forest habitat lost and number of Monarchs displaced from development activities and wildfire is the same as described under Scenario Three. Subsequent impacts to the species’ resiliency due to potential disturbances to Monarch behavior from increased activity and more importantly, a decline in abundance, are also similar to those described under Scenario Three. However, under this scenario, we assume improvements to the civilian BTS interdiction program and facilities to include Wildlife Services-certified quarantine and containment facilities at Saipan and Tinian air and sea ports. The improved interdiction program and facilities would substantially mitigate for the significant increase in incoming cargo, equipment, and vehicles from civilian and military activities and preclude an increase beyond the current low to moderate level of BTS risk.

5.2.5 Scenario Five

Under this final scenario, we envision the same displacement impacts to the Tinian Monarch as under Scenario Four in addition to a lower risk of BTS establishing on the island. We believe it is possible to maintain low to moderate BTS risk level by including several ‘additional safeguards’ beyond the improved civilian facilities and operations envisioned under Scenario Four. These ‘additional safeguards’ and improvements to BTS interdiction and the overall BTS effort would include:

• 100% redundant dog inspections for all cargo (military and civilian) arriving to Tinian directly or indirectly from Guam (as described under Scenario Four) but with no exceptions including privately shipped cargo and DOD munitions and cargo for tactical operations;

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• Consolidating administration and direct oversight of the CNMI BTS program under an appropriate entity, such as USDA Wildlife Services or one with similar capacity;

• Establishment and maintenance of a dedicated dog team on Tinian available for sea and air port inspections 24 / 7;

• Establishment and maintenance of 6 to 10 trained Rapid Response Team members on Tinian;

• Construction and maintenance of permanent BTS barriers at both the Saipan sea and air ports and per DIVERT, at the Tinian airport (per Scenario Four);

• Establishment of an independent monitor / auditor to ensure all Guam DOD cargo bound for Tinian is inspected and reported

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Table 17. Analysis of Tinian Monarch future conditions under five scenarios over time. Scenario One Scenario Two Scenario Three Scenario Four Scenario Five No military development, some Planned military development Planned military development per the CJMT Planned military development per the CJMT Planned military development per the increase in civilian development, per the CJMT DEIS, no increase DEIS, some increase in civilian development, DEIS, some increase in civilian CJMT DEIS, some increase in civilian and no improvements to civilian in civilian development, and no and no improvements to civilian BTS development, and improvements to the development, improvements to the civilian BTS interdiction program and improvements to civilian BTS interdiction program and facilities no civilian BTS interdiction program and BTS interdiction program and facilities on Future facilities interdiction program and improvements to the civilian BTS interdiction facilities on Saipan and Tinian. Saipan and Tinian, and ‘additional Condition facilities program and facilities safeguards’ for the BTS program. 16 years 66 years 16 years 66 years 16 years 66 years 16 years 66 years 16 years 66 years 1 civilian 3 civilian 3 civilian no civilian no civilian 1 civilian 3 civilian 3 civilian 1 civilian 3 civilian 3 civilian 1 civilian 3 civilian 3 civilian project projects projects projects projects project projects projects project projects projects project projects projects Tinian Monarch -1,330 (civ) -4,200 (civ) -8,400 (civ) -1,330 (civ) -4,200 (civ) -8,400 (civ) -1,330 (civ) -4,200 (civ) -8,400 (civ) displacement— -1,330* -4,200* -8,400* -7,200** -7,200** -7,200 (mil) -7,200 (mil) -7,200 (mil) -7,200 (mil) -7,200 (mil) -7,200 (mil) -7,200 (mil) -7,200 (mil) -7,200 (mil) individuals -8,530 -11,400 -15,600 --8,530 -11,400 -15,600 --8,530 -11,400 -15,600 Tinian Monarch displacement— 1.46% 4.63% 9.26% 7.94% 7.94% 9.41% 12.57% 17.21% 9.41% 12.57% 17.21% 9.41% 12.57% 17.21% % of pop^ -1,050 ac -350 ac (civ) -350 ac (civ) -2,100 ac (civ) Forest habitat -350 ac (civ) -1,050 ac (civ) -2,100 ac (civ) -1,050 ac (civ) -2,100 ac (civ) (civ) -1,800 ac -1,800 ac ≥-1,800 ac loss through -350 ac -1,050 ac -2,100 ac -1,800 ac ≥-1,800 ac -1,800 ac (mil) -1,800 ac (mil) ≥-1,800 ac (mil) -1,800 ac (mil) ≥-1,800 ac (mil) -1,800 ac (mil) (mil) (mil) development -2,150 ac -2,850 ac ≥-3,900 ac -2,850 ac ≥-3,900 ac (mil) -2,150 ac -2,150 ac ≥-3,900 ac -2,850 ac Habitat loss—% of total forest on 2.07% 6.21% 13.02% 10.65% 10.65% 12.77% 14.79% 23.67% 12.77% 14.79% 23.67% 12.77% 14.79% 23.67% Tinian* Risk of BTS Low to moderate Moderate to high High to extreme Moderate to high Low to Moderate Establishing^^ Substantial additional risk of Substantial additional risk of wildfire within the Little to no additional risk of wildfire within Little to no additional risk of wildfire within wildfire within the MLA if live- MLA if live-fire training is not restricted to the MLA if live-fire training is restricted to the MLA if live-fire training is restricted to Some additional risk of wildfire fire training is not restricted to periods of the wet season when Keetch-Byram periods of the wet season when Keetch- periods of the wet season when Keetch- Wildfire due to increased civilian activity periods of the wet season when Drought Index is 300 or lower; Some additional Byram Drought Index is 300 or lower; Some Byram Drought Index is 300 or lower; Keetch-Byram Drought Index is risk of wildfire due to increased civilian additional risk of wildfire due to increased Some additional risk of wildfire due to 300 or lower. activity. civilian activity. increased civilian activity.

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*See above discussion regarding estimate of impact by civilian development ^out of an estimated 90,634 Monarchs (Camp 2015 in litt) *out of 16,892 total forested acres (ac) on Tinian ** The number of Tinian Monarchs displaced by the footprint of the CJMT DEIS, not including potential displacement by activities (U.S. Navy 2015 CJMT DEIS); the U.S. Navy’s estimate was slightly higher than that suggested by our own analysis and depending upon the dataset used. *** Approximately 1,800 ac (from U.S. Navy 2015 CJMT DEIS) ^^as described by Perry and Vice (2008) and in consideration of changes to risk factors we have identified since 2009

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Appendix A – Description of Guguan Island

Guguan, like Tinian, is an island of the CNMI, and although Guguan is small in area (1.49 mi2, 3.86 km2), it comprises a relatively intact native ecosystem, uninhabited, free of feral ungulates, with healthy populations of several native forest plants, seabirds, and forest birds (Figure 42). Guguan’s intact native forest covers much of the island (409 ac or 40 %; Figure 42, Figure 43, and Figure 44) and supports a diverse range of native plants and a high diversity of wildlife including seabirds, land birds, and coconut crabs (Cruz et al. 2000, p. 38; Brainard et al. 2012, p. 3).

Figure 42. Photograph of Guguan Island (Dick Moore, U.S. Geological Survey).

In 1980, the entirety of Guguan was designated a conservation area by the CNMI government and is afforded some measures of protection: for example, human habitation or building of non- conservation-related structures on the island is prohibited (Berger et al. 2005, p. 15). These features make Guguan an ideal protected site for the first translocations of Tinian Monarchs, which took place in 2015 and 2016.

The island is roughly circular in shape, with a length of 1.7 mi (2.8 km) and a width of 1.4 mi (2.3 km) and an area of 1.49 mi2 (3.86 km2). Unlike most islands within the Mariana archipelago, Guguan is believed to have never been inhabited by the Chamorro people or any human population (Russell 1998, pp. 83−89; Brainard et al. 2012, pp. 2-3). Also notably, similar to Sarigan and Farallon de Pajaros within the CNMI, dense seabird colonies inhabit many portions of the island (Ohba 1994, p. 16; Berger et al. 2005, p. 12).

Guguan consists of two stratovolcanoes: the younger, southern peak measuring 942 ft (287 m) in elevation, and the older, northern peak measuring 863 ft (263 m) in elevation. Although the last recorded eruption on the island occurred from the northern peak in approximately 1883, Guguan is still considered geologically active, as evidenced by subsidence of several topographical

179 Tinian Monarch SSA Version 1.0 features in the late 19th and early 20th century (Cruz et al. 2000, p. 4). While the northwestern side of the island remains scarcely covered with vegetation due to the prominence of the 19th century lava flows, the strongly eroded southern side of the island forms a low plateau ringed with hills and valleys, all densely vegetated with a variety of native and non-native plant species (Cruz et al. 2000, p. 3-4; Brainard et al. 2012, pp. 2-3).

Guguan’s southern plateau is dominated by sword grass (Miscanthus floridulus), while the rugged hills and valleys support dense forests with unusually high densities of native species, including Erythrina variegate, Morinda citrifolia, Pandanus argenteus, Pandanus tectorius, and Trema orientalis among the group of primary forest species. Scattered small numbers of coconut palms also are present, likely remaining from previous efforts to establish plantations (Cruz et al. 2000, p. 5).

Figure 43. Photograph detailing forest habitat distribution on the island of Guguan.

In addition to supporting the translocated and now reproducing Tinian Monarchs, Guguan also supports three endangered animals species in relative abundance: the Mariana fruit bat (Pteropus mariannus), the Micronesian megapode (Megapodius laperouse), and the Slevin’s skink (Emoia slevini) (USFWS 20154, p. 59427). In addition to the aforementioned seabird colonies, other native birds inhabiting the island include the Micronesian starling (Aplonis opaca) and the Micronesian honeyeater (Myzomela rubrata) (Brainard et al. 2012, p. 3). The diverse and abundant bird populations present on Guguan are able to thrive in the absence of

180 Tinian Monarch SSA Version 1.0 monitor lizards, feral animals, or other large predators, although rats are fairly abundant on some parts of this island (Cruz et al. 2000, p. 32; Brainard et al. 2012, p. 3).

Figure 44. Map comparing Guguan to scale with Tinian and the extent of forest cover on both.

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Appendix B – Canopy, Subcanopy, and Understory Species Commonly Found on Tinian

Canopy Subcanopy Understory Ground Cover

Native Forest Artocarpus Discocalyx Aglaia mariannensis (almost nonexistent) mariannensis megacarpa Barringtonia asiatica Aidia cochinchinensis Hedyotis spp.

Allophylus Nephrolepis Claoxylon spp. timoriensis bisserrata Cordia subcordata Eugenia palumbis N. hirsutula

Cyanometra E. reinwardtiana Phyllanthus marianus ramiflora Elaeocarpus joga Hibiscus tiliaceus Piper guamense

Ficus prolixa Maytenus thompsonii

Hernandia Meiogyne labyrinthica cylindrocarpa H. sonora Psychotria mariana

Merrilliodendron Xylosma nelsonii megacarpum Ochrosia mariannensis O. oppositifolia

Pandanus dubius

P. tectorius

Pisonia grandis

Pouteria obovata

Premna obtusifolia

Casuarina Lantana camara equisetifolia Pithecellobium dulce

Secondary-Mixed Forest

Acacia confusa Albizia lebbeck Cocos nucifera Delonix regia Leucaena leucocephala Solanum guamense

Leucaena leucocephala

Tangantangan Forest

Acacia confusa

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Albizia lebbeck Casuarina equisetifolia Delonix regia Melanolepis multiglandulosa var. glabrata

NOTE: Species listed are all including, but not limited to. Sources: Falanruw et al. 1989, pp. 6–9; Little and Skolmen 1989, p. 144; Mueller-Dombois and Fosberg 1998, pp. 247, 252–253, 257, 268, 270–272; Ohba 1994, pp. 19–29; Raulerson and Rinehart 1991, pp. 6–7, 11, 13–14, 20, 24, 28, 33, 47, 50, 52–53, 56, 62–63, 68–69, 72, 77, 84, 88, 91, 96, 104; Stone 1970, pp. 9, 14, 18–24; and Wiewel et al. 2009, pp. 206–207

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Appendix C – List of Directives and Policy Driving the Realignment of US Forces in the Pacific Region Including the CJMT (taken from the 2015 CJMT DEIS) According to the 2015 DEIS (U.S. Navy 2015, p. ES-2), the following studies, reports, assessments, and international statements and agreements document the need for additional training capabilities in the Western Pacific, and specifically in the CNMI:

The 2009 Institute for Defense Analyses Study assessed the ability of the Service Components to meet training requirements in the U.S. Pacific Command’s Area of Responsibility (Institute for Defense Analyses 2009).

In 2010, the Quadrennial Defense Review (hereafter “2010 QDR”) evaluated global U.S. military strategy and priorities (Department of Defense 2010). The 2010 QDR requires a more widely distributed U.S. presence in Asia.

In November 2011, President Obama underlined the Asia Pacific’s regional importance in his speech to the Australian parliament.

The bilateral Realignment Roadmap agreement between the U.S. and Japan calls for transforming Guam and the CNMI into a hub for security activities in the region (Security Consultative Committee 2012).

In 2013, the Training Needs Assessment: An Assessment of Current Training Ranges and Supporting Facilities in the U.S. Pacific Command Area of Responsibility (hereafter the “Assessment”) identified and validated unfilled training requirements for units/commands in the U.S. Pacific Command Area of Responsibility (Department of the Navy [DoN] 2013a). This process provided an initial list of 62 unfilled training requirements, with all Service Components identifying unfilled training needs in the Western Pacific.

The 2013 CNMI Joint Military Training Requirements and Siting Study (DoN 2013b) (hereafter referred to as “the Siting Study”) refined the analysis of unfilled training requirements in the Mariana Islands that was identified in the 2013 Training Needs Assessment. The initial 62 requirements were refined by the Executive Agent (U.S. Marine Corps Forces Pacific) to review previously identified Pacific-wide unfilled training requirements for those that could potentially be filled in the CNMI. This resulted in reducing the number of unfilled training requirements carried forward into this Siting Study from 62 to 42. These 42 unfilled training requirements served as the basis for developing the proposed action and alternatives in this EIS/OEIS.

In 2014, the Quadrennial Defense Review (hereafter “2014 QDR”) re-evaluated global U.S. military strategy and priorities (Department of Defense 2014). The 2014 QDR confirmed the U.S. military’s continued commitment to rebalance the Asia-Pacific region, which is increasingly central to U.S. political, economic and security interests.

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In Litt and Personal Communications

Amidon, F. 2017, in litt. Unpublished habitat analysis by USFWS PIFWO biologist, Fred Amidon.

Amidon, F. 2016, personal communication. Email correspondence between USFWS PIFWO biologists, Fred Amidon, Mike Richardson, and Annie Marshall, regarding the possibility that drought may have led to the apparent decline in TIMO population observed during official island-wide surveys of Tinian in 2008.

Atkinson, C. 2014, personal communication. Email between USGS biologist, Carter Atkinson, and USFWS PIFWO biologist, Annie Marshall, regarding analysis of Tinian Monarch pox infection samples taken during the post delisting monitoring studies 2006-2008, 2017, March 17, 2014.

Boland, J. 2014, personal communication. Email between (former) USFWS PIFWO biologist, Julia Boland, and USFWS PIFWO biologist, Carrie Harrington regarding fires on Rota, February 4, 2014.

Bruns, D. 2017, in litt. USFWS PIFWO biologist. Unpublished report on CJMT fire risk analysis.

Camp, R. 2016, in litt. Unpublished report on the reanalysis conducted for all four island-wide Tinian forest bird surveys. Sent by email from USGS biologist, R. Camp to USFWS biologist M. Richardson, August 24, 2016.

Campbell, E. 2017, personal communication. Email from former Invasive Species Program Supervisor, Earl Campbell, to USFWS biologist, Mike Richardson, regarding the current state of the brown treesnake program in Guam and the CNMI and the risk of BTS introduction to Tinian as a result of the CJMT including tactical activities.

(Commonwealth of the Northern Mariana Islands) CNMI. 2005. Letter from the Office of the Governor regarding the promulgation of regulations to control the introduction and prevent the further dissemination of injurious pests and diseased animals into the Commonwealth under the authority granted by the Commonwealth Plant and Animal

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Quarantine Act and the Animal Health Protection and Disease Control Act, 2 CMC § 5301, et seq., and 2 CMC § 5320, et seq. 9 pp.

(Commonwealth of the Northern Mariana Islands) CNMI. 2015, in litt. Official comments from the CNMI government regarding the 2015 DEIS for the CJMT.

Cravalho, D. 2017, personal communication. Email between USFWS PIFWO Invasive Species Program acting Supervisor, Domingo Cravalho, and USFWS PIFWO biologist, Mike Richardson, regarding the status of brown treesnake interdiction and cargo barriers in Guam and the CNMI.

Cravalho, D. 2018, personal communication. Email between USFWS PIFWO Invasive Species Program acting Supervisor, Domingo Cravalho, and USFWS PIFWO biologist, Mike Richardson, regarding the implementation dates of dog detector teams in the CNMI for BTS inspection.

Cravalho, D. 2018, in litt. Informal peer review provided by USFWS PIFWO Invasive Species Program acting Supervisor, Domingo Cravalho for the draft Tinian Monarch Status Assessment, dated March 2018.

Donmoyer, K. 2017, personal communication. Email between USFWS PIFWO Invasive Species program biologist, Kevin Donmoyer, and USFWS PIFWO biologist, Mike Richardson, regarding the status of the brown treesnake program in the CNMI including Tinian, December 12, 2017.

Duponcheel, L. 2017, personal communication. Emails between the Tinian Cattlemen’s Association Secretary and Northern Marianas College agricultural extension agent, Lawerence Duponcheel, and USFWS PIFWO biologist, Mike Richardson, regarding the status of the Tinian ranching industry and the ranch leases within the Tinian military lease back area, May 2; July 19; July 22, 2017.

Federal Emergency Management Agency (FEMA). 2014, in litt. Disaster declarations for Commonwealth of the Northern Mariana Islands, http://www.fema.gov/disasters/grid/state-tribal-goverment/82, accessed February 5, 2014.

Flores, 2014, personal communication. Email between (former) USDA-NRCS area resource conservationist, Jacqueline Flores, and USFWS PIFWO biologist, Carrie Harrington, regarding the status of feral cattle on Tinian, July 9, 2015.

Gosnell, R. 2017, personal communication. Telephone conversation and email between USDA, APHIS, Wildlife Services BTS interdiction program administrator, Robert Gosnell, and USFWS PIFWO biologist, Mike Richardson, regarding the status of the BTS interdiction program including canine detection program in Guam, October 4, 2017.

Invasive Species Specialist Group-Global Invasive Species Database (ISSG-GISD). 2007, in litt. Varanus indicus (reptile), http://www.issg.org/database/species/ecology/asp?si=1065&fr=1&sts=sss&lang=EN, accessed April 22, 2014.

Kremer, S. 2014, pers comm. Email between (former) USFWS PIFWO biologist, Shelly Kremer, and USFWS PIFWO biologist, Carrie Harrington, regarding the status wildfires in the CNMI, February 4, 2014.

Mahoney, T. 2017, personal communication. Email between USFWS PIFWO biologist, Dawn Bruns, and T. Mahoney, fire ecologist, United States Forest Service, Fire and Aviation Management Pacific Southwest Region.

Marshall, A. 2017, personal communication. Email between USFWS PIFWO biologist, Annie Marshall, and USFWS PIFWO biologist, Mike Richardson, regarding the status of a goat population observed on southern Tinian, August 25, 2017.

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Mullin, S. 2016, in litt. “Trip Report, Guguan May 2016”. Unpublished memorandum from CNMI-DFW biologist, Steve Mullin, to CNMI-DFW director, Manny Pangelinan, regarding the 2016 trip to Guguan to survey the 2015 Tinian Monarch translocation effort and to translocate additional Monarchs to the island.

Mullin, S. 2016, personal communication. Email between CNMI DFW biologist, Steve Mullin, and USFWS PIFWO biologist, Mike Richardson, regarding the status of the Tinian Monarchs translocated to Guguan from Tinian and their absence of pox infection, November 26, 2017.

National Oceanic Atmospheric Administration (NOAA). 2011, in litt. Tropical cyclones, hurricanes, and typhoons, http://www.aoml.noaa.gov, accessed February 3, 2014.

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Reed, R. 2017, in litt. Peer review received from USGS biologist, Robert Reed, regarding the status of the BTS program on Guam and in the CNMI and the risk of BTS incursion to Tinian. August 2017.

Reed, R. S. 2017, personal communication. Emails between USGS biologist, Robert Reed, and USFWS PIFWO biologist, Mike Richardson, regarding paucity of gravid and large BTS in live captures and status of rapid response program, September 19, 22, 2017.

Siers, S. 2017, in litt. Peer review received from USDA biologist, Shane Siers, regarding the status of the BTS program on Guam and in the CNMI and the risk of BTS incursion to Tinian. August 2017.

Siers, S. 2017, personal communication. Email between USDA biologist, Shane Siers, and USFWS PIFWO biologist, Mike Richardson, regarding paucity of gravid and large BTS in live captures and concerns about programmatic barriers to using ADS to control an incipient population, September 16, 2017.

Stanford 2017, in litt. Peer review received from USFWS PIFWO Invasive Species program biologist, James Stanford, regarding the status of the BTS program on Guam and in the CNMI and the risk of BTS incursion to Tinian. August 2017.

USFWS. 2007, in litt. Reinitiation of the 1999 Biological Opinion of the U.S. Fish and Wildlife Service for U.S. Army Military Training at Makua Military Reservation, Island of Oahu, June 22, 2007. 639 pp.

USFWS in litt. 2013 comments on pre-CJMT DEIS

USFWS in litt. 2015 comments on CJMT DEIS

USGS in litt. 2017. Data for rapid response actions for Guam cargo since 2002. Unpublished data provided by email from Patrick Barnhard, USGS Guam.

(U.S. Department of Agriculture (USDA)) Natural Resources Conservation Service (NRCS), Pacific Islands Area. 2015, in litt. Ranching in the Islands Tinian Beef. http://www.nrcs.usda.gov/wps/portal/nrcs/detail/pia/newsroom/features/?cid=nrcs142p2_ 037691, accessed July 10, 2015.

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Vogt, S. 2016, personal communication. Email between Navy biologist, Scott Vogt, and USFWS PIFWO biologist, Mike Richardson, regarding anecdotal observations and field studies of monitor lizard prey preferences in the Mariana Islands, August 21, 2016.

Willsey, T. 2016, personal communication. Email between USFWS PIFWO biologist, Tyler Willisey, and USFWS PIFWO biologist, Mike Richardson, regarding the status of Altercity Resort clearing on Tinian, October 6, 2016.

Willsey, T. 2017, personal communication. Email between USFWS PIFWO biologist, Tyler Willisey, and USFWS PIFWO biologist, Mike Richardson, regarding the occurrence of goats and wildfires on Tinian in 2016, September 20, 2017.

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