Species Status Assessment Report for the San Clemente Island Paintbrush (Castilleja grisea)

Version 1.0

Photo courtesy of Tiffany McFarland

March 2020

U.S. Fish and Wildlife Service Pacific Southwest Region Sacramento, CA ACKNOWLEDGEMENTS

This document was prepared by the Texas A&M Natural Resources Institute in cooperation with the U.S. Fish and Wildlife Service and the United States Navy as part of the Service’s San Clemente Island Species Status Assessment Team.

We would also like to recognize and thank the following individuals who provided substantive information and/or insights for our SSA: Gary Wallace, Kimberly O’Connor, Bryan Munson, Melissa Booker, Dawn Lawson, Sula Vanderplank, Sandy Vissman, and Andrew Bridges.

Additionally, valuable input into the analysis and reviews of a draft of this document were provided by Mitchell McGlaughlin and Andrea Williams. We appreciate their input and comments, which resulted in a more robust status assessment and final report.

Suggested reference:

U.S. Fish and Wildlife Service. 2020. Species status assessment report for the San Clemente Island Paintbrush (Castilleja grisea), Version 1.0. March 2020. Sacramento, CA.

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EXECUTIVE SUMMARY

This Species Status Assessment (SSA) provides an analysis of the overall species viability for the San Clemente Island Paintbrush (Castilleja grisea). To assess the viability of this species, we, the U.S. Fish and Wildlife Service (Service), used the conservation biology principles of resiliency, redundancy, and representation (3 Rs). Specifically, we identified the species’ ecological requirements and resources needed for individual survival and reproduction. We described the stressors (threats) influencing these resources and evaluated current levels of population resiliency and species redundancy and representation using available metrics to forecast the ability of this species to sustain populations into the future. Castilleja grisea is a highly branched perennial subshrub endemic to San Clemente Island (SCI), the only representative of the genus Castilleja found on the island. All members of the genus Castilleja are considered hemiparasitic, meaning they are able to penetrate a host plant’s root tissue and derive water, nutrients, or photosynthates from the host plant. They are also capable of photosynthesis and can also exist without a host. The fire tolerance of C. grisea is unknown, but it is likely resilient to occasional fires based on phylogeny and has been seen to persist in areas after fires. At listing under the Endangered Species Act (ESA), nonnative herbivores were the primary threat to Castilleja grisea. As a result of their removal by 1992, habitat conditions improved and led to increases in the cover of native and nonnative plants on the island, including C. grisea and several other threatened and endangered species. The C. grisea population numbered approximately 1,000 individuals in 1984, with 15 watersheds known to be occupied by 1989. The current island-wide population is estimated at 42,104 individuals across 87 watersheds. In the absence of the primary threat, additional threats to C. grisea that have been identified include: (1) land use, (2) erosion, (3) nonnative plants, (4) fire and fire management, and (5) climate change. SCI is owned by the U.S. Department of the Navy (Navy) and, with its associated offshore range complex, the island is the primary maritime training area for the Pacific Fleet and Sea Air and Land Teams (SEALs) and supports training by the U.S. Marine Corps, the U.S. Air Force, and other military organizations. As such, portions of the island receive intensive use by the military and can involve the movement of vehicles and troops over the landscape and can include live munitions fire, incendiary devices, demolitions, and bombardment. Altogether, 34.8% of the island’s area is located in designated training areas, and much of the island is void of any infrastructure. Most of the population of Castilleja grisea falls outside of these designated training areas; thus, direct impacts to the population are minimal. Erosion, neither naturally occurring nor that induced by human activities, has affected any documented occurrence of C. grisea to date. While the full impact of invasive species on C. grisea is unknown, the effects are likely minimal or localized, given the expansion of C. grisea on the island despite the presence of invasive species. Future impacts from fire remain uncertain. Fires are typically small, of low severity, and infrequent, and given they are most often ignited due to training, their typical locations are somewhat predictable. However, an increase in the frequency or severity of fires in the future, potentially due to short-term impacts of climate change, increased training, or an increase in invasive grasses, could have additional impacts to C. grisea. We found that 39% of watersheds (34) are located in areas with no identifiable major threats and represent half of the total number of individuals on SCI. We found that 65 watersheds (75%), totaling 35,702 individuals (85%) had either zero or low total threats.

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To help further ameliorate these remaining threats, the Navy implements a wildland fire management plan (US Navy 2009) to address fire-management. The Navy addresses erosion and targeted removal of invasive species, in general, through the Integrated Natural Resources Management Plan (INRMP), addresses training-related erosion through the Erosion Control Plan, and addresses further introduction of invasive species through implementation of the biosecurity plan. Military training on SCI has been and will continue to be dynamic as it evolves to meet new requirements, and changes that may affect Castilleja grisea are unknown. For instance, future training may include introduction of new training methods, equipment, and activities that would affect fire-frequency, fire-severity, or erosion. However, changes are expected to be incremental, as they have been in the past, and impacts to federally listed and sensitive species will be addressed in environmental analyses required under the National Environmental Policy Act (NEPA) and ESA. The factors that appear to have the most potential to impact species viability in the future are land use, fire, and climate change, including potential compounded effects. However, we are unable to address the long-term impacts of climate change because how climate change will affect SCI remains unclear. Most importantly, the persistence and timing of the fog layer, which provides moisture and a refuge from the full impacts of warming, is unknown. However, we assume that climate change will not have major effects on Castilleja grisea in the next 20 to 30 years, although we account for possible short-term climate impacts. Therefore, we consider the future of Castilleja grisea in terms of its threats and conservation efforts over the next 20 to 30 years. Therefore, to assess the future viability of Castilleja grisea, we considered three future scenarios that encompass the uncertainty associated with fire and military training, as well as uncertainty in the levels of recruitment over time: Scenario 1, our status quo scenario, assumes fire patterns and severity continue and current training impacts are maintained. Scenario 2 assumes increased training impacts and increased fire frequency/severity (due to short-term climate change impacts or the increase in training). Scenario 3 also assumes a threat increase, but assumes extreme fire frequency/severity and extreme training impacts. We present the resulting population size as a range using a low and high recruitment estimate (Table A). Our methods predict that, in the next 20 to 30 years, the number of occupied watersheds are likely to increase, assuming that the species will be able to colonize new watersheds; at worst, without new colonization, we predict the number of watersheds would decrease by 7. The numbers of watersheds considered highly or very highly resilient stays the same in the best case and decreases by 7 in the worst. The resulting population estimates in all three scenarios do not drop below 38,000 individuals, and the current population estimate is within the range of estimates for the scenarios where additional threats are modeled (Scenarios 2 and 3) (Table A). In the absence of major threats (Scenario 1), with no factors limiting sustained recruitment, we do not expect any stochastic impacts to affect Castilleja grisea in a significant way over the next 20 to 30 years. We therefore expect that the entire island population is likely to increase in resiliency under Scenario 1. Even under extreme fire and training (Scenario 3), despite localized extirpations in some of the northernmost and southernmost parts of its range, the total population is projected to potentially see a decrease of about 3,000 individuals island- wide and may increase from current. Thus, we still expect the island population will remain resilient to normal stochastic impacts (Table A). We likewise do not expect representation or redundancy to decrease in a meaningful way in our scenarios. Thus, we expect that the species would be able to sustain most major

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catastrophic events, such as unprecedented fires, major erosion events (such as caused by periods of heavy rainfall), or an outbreak of an invasive, predatory, or pathogenic species, or a change in environmental conditions. Only an unusually severe and unprecedented catastrophic impact could threaten the viability of the population. For instance, if the fire footprint changes and more severe fires break out where the species is numerous, like along the eastern escarpment, could have major impacts to the population size, and thus, redundancy. Also, severe or extensive droughts, coupled with other stressors, could have substantial impacts to species viability. A severe drought could impact the vegetation island-wide, although we’d expect at least some individuals would be able withstand even severe drought. Still, like all endemics, C. grisea has a small range and is confined to SCI and would be unable to disperse elsewhere.

Table A. The number of watersheds considered of very high, high, moderate and low resiliency and the total estimated population as considered current and in each of our four future scenarios. Watershed numbers in parentheses represent the total watersheds assuming recruitment into new watersheds, with a range from low (5 new watersheds) to high (10 new watersheds) recruitment. Watershed Resiliency Very High High Moderate Low Total Individuals Current 16 32 19 20 87 42,104 Scenario 1 17 31 19 20 (25-30) 87 (92-97) 43,489–51,773 Scenario 2 16 26 24 18 (23-28) 84 (89-94) 40,435–48,137 Scenario 3 14 27 21 18 (23-28) 80 (85-90) 38,078–45,330

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TABLE OF CONTENTS

ACKNOWLEDGEMENTS ...... ii EXECUTIVE SUMMARY ...... iii TABLE OF CONTENTS ...... vi LIST OF TABLES ...... ix LIST OF FIGURES ...... xi Section 1 – INTRODUCTION AND ANALYTICAL FRAMEWORK ...... 13 1.1 Status of the Species ...... 14 Section 2 – SPECIES BIOLOGY ...... 15 2.1 Taxonomy ...... 15 Genetics...... 15 2.2 Species Description ...... 16 2.3 Range and Distribution ...... 16 2.4 Habitat ...... 18 2.5 Life History ...... 20 Reproduction ...... 21 Life Span ...... 22 Fire tolerance ...... 22 2.6 Population trends and abundance...... 23 2.6.1. Current distribution ...... 26 Section 3 – INDIVIDUAL AND SPECIES NEEDS ...... 28 3.1 Population Resiliency ...... 29 3.1.1 Individual Level ...... 30 3.1. 2 Population Segment (Watershed) Level ...... 30 3.2 Species Redundancy and Representation ...... 31 3.2.1 Species Level ...... 31 Section 4 – FACTORS INFLUENCING VIABILITY ...... 32 4.1 Land use (direct effects) ...... 33 Management efforts ...... 38 Summary ...... 38 4.2 Erosion and Roads ...... 39 Management efforts ...... 40 Summary ...... 41 4.3 Invasive plants ...... 42

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Management efforts ...... 43 Summary ...... 43 4.4 Fire ...... 44 Management efforts ...... 50 Summary ...... 51 4.5 Climate Change ...... 52 Summary ...... 53 4.6 Other Threats ...... 53 4.7 Summary of Factors Influencing Viability ...... 53 Section 5 –CURRENT CONDITION ...... 56 5.1 Populations and Management Units ...... 57 5.2 Methods for Estimating Current Condition ...... 57 Within individual watersheds ...... 58 Island-wide ...... 58 5.3 Current Condition Results...... 58 Within individual watersheds...... 58 Island-wide ...... 60 5.4 Current Population Resiliency ...... 60 5.5 Current Species Representation ...... 62 5.6 Current Species Redundancy ...... 63 Section 6 – FUTURE CONDITIONS AND VIABILITY ...... 63 6.1 Introduction ...... 64 6.2 Methods...... 65 Growth and recruitment: ...... 65 Fire frequency and severity:...... 66 Land Use/Training ...... 67 6.3 Models and Scenarios ...... 67 6.4 Future Resiliency ...... 68 6.5 Future Representation ...... 70 6.6 Future Redundancy ...... 71 6.7 Limitations and Uncertainties ...... 71 6.8 Conclusions ...... 73 References Cited ...... 74 APPENDIX B ...... 85

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APPENDIX C ...... 87

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LIST OF TABLES

Table 1.Surveyed number of Castilleja grisea individuals during various survey years (USFWS 1984, p. 58; Junak and Wilken 1998, p. 82; Junak 2006, p. 47; Vanderplank et al. 2019, p. 7). Survey extents are unknown...... 24 Table 2. Number of watersheds known to be occupied by Castilleja grisea recorded by decade. These represent only surveyed watersheds where C. grisea were found in that decade and do not account for watersheds that may have remained populated but were not surveyed in subsequent decades...... 24 Table 3. Summary of training areas, their size, use, and the threats to Castilleja grisea within each...... 35 Table 4. The numbers of locations and total individuals that occur within each of the training area types based on the distribution of Castilleja grisea considered current...... 36 Table 5. Fire severity classes and definitions, reproduced from the US Navy 2009 Fire Management Plan for SCI, with severity classes adapted from the National Park Service (1992)...... 45 Table 6. Numbers and percentages of watersheds and individuals assessed to have varying levels of threats: none, low (threats that could potentially affect <50% of the locations, individuals, or area within the watershed), or medium (threats that could potentially affect ≥50% of the locations, individuals, or area within the watershed). Threats identified include locations or individuals near a road or in the TARs or Impact Areas, and percent of the watershed area that burned once or >1 time in the past 20 years (1999–2018). Further, AVMA watersheds are considered to have a low threat level, whereas watersheds in the Impact Areas are assumed to have a moderate threat level...... 55 Table 7. Occupied watersheds that may have lost Castilleja grisea during the 2012 and 2017 fire seasons where fires burned at a severity that can kill shrubs. Percentages are given for the numbers of individuals that could have been affected in each severity class, as well as the total percent of individuals that may have experienced negative effects of the fire, and the resulting adjusted estimate of the total individuals...... 59 Table 8. Total locations and individuals considered current, broken down into survey points retained by year. Our methodology estimates approximately 48,181 individuals at 601 locations...... 60 Table 10. The number of watersheds that fall into each of our resiliency categories, the numbers of individuals the watersheds in each category accounts for, and the percent of the total island wide population represented...... 61 Table 11. The number of watersheds considered of very high, high, moderate and low resiliency and the total estimated population as considered current and in each of our four future scenarios. Watershed numbers in parentheses represent the total watersheds assuming recruitment into new watersheds, with a range from low (5 new watersheds) to high (10 new watersheds) recruitment...... 69 Table 12. Location points and individuals of Castilleja grisea counted at points where a fire had burned within the past 10 years. Year of last fire and the number of years that have passed since the fire are included...... 80 Table 13. Occupied watersheds, including the current number of locations and individuals present (adjusted for the 2017 fire season), the percent of locations and individuals near roads, the percent of each watershed that burned in the last 20 years and more than once

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in that timespan, whether the watershed is in the AVMA or IA, and the projected individuals (within a range given low versus high growth) that will occur in that watershed in 20-30 years under each of three scenarios. Threats are represented as low (gold) and moderate (pink). Numbers of individuals under current and future scenarios are represented as low (pink), moderate (gold), high (light green), very high (dark green) and extirpated (red), depending on population size and number of locations (see Section 5.4 and Section 6.4)...... 82 Table 14. Conservation measures for terrestrial plants on San Clemente Island (SCI) as relevant to Castilleja grisea, were taken from the Biological Opinion (BO; USFWS 2008) and Table 3-48 of the Integrated Natural Resources Management Plan (INRMP; US Navy 2013). Taken from Vanderplank et al. 2019, p. 14...... 85 Table 15. The canyon names used to represent the occurrences in the 2013 downlisting rule, the element occurrence numbers from the California Natural Diversity Database that were included, and the watersheds that those canyons overlay...... 88

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LIST OF FIGURES

Figure 1. Species Status Assessment Framework. From USFWS 2016...... 14 Figure 2. Location of San Clemente Island in the southern Channel Islands off the coast of California...... 17 Figure 3.Vegetation types on SCI and locations of Castilleja grisea collected during 2011 and 2012 surveys. From Vanderplank et al. 2019...... 19 Figure 4. Castilleja grisea distribution from the 2011 and 2012 surveys and soil types. From Vanderplank et al. 2019...... 20 Figure 5. Distribution of locations of Castilleja grisea (CAGR) recorded per decade, with occupied watersheds in gray. Known locations occupied 15 watersheds between 1980 and 1989, 16 watersheds between 1990 and 1999, 56 watersheds between 2000 and 2009, and 75 watersheds between 2010 and 2014. Only records documented in each decade are shown, though they may have remained extant in subsequent decades when they were not surveyed or located...... 25 Figure 6. Distribution of Castilleja grisea considered current as per methodology described in Section 2.6, with individuals per location and occupied watersheds indicated in dark gray. Historical locations are shown as gray dots, and historically occupied watersheds are in light gray. Occupation at these historical points and within these historical watersheds is unknown, but they are not considered occupied for this SSA...... 28 Figure 7. Habitat and population factors that influence the viability of Castilleja grisea throughout its range...... 30 Figure 8. Factors that affect population resiliency in Castilleja grisea. This is not a complete compilation but represents the most important factors...... 33 Figure 9. Locations of Castilleja grisea (CAGR) as considered current in relation to the training areas on SCI, including the Impact Areas, the Training Areas and Ranges (TARs), the Assault Vehicle Maneuver Areas (AVMAs), the Infantry Operations Area (IOA), and the Shore Bombardment Area (SHOBA), which occupies the southern third of the island. Current Restricted Access Areas (RAAs) are also shown, but these change as unexploded ordnance are removed...... 37 Figure 10. Total acres on SCI that have burned annually in wildfires and acres that were recorded to have burned at a moderate to high severity (severity classes 1, 2, or 3)...... 46 Figure 11. Acres burned annually on SCI for years where fires were estimated since listing. Fire management was initiated around 1999...... 48 Figure 12. Locations of Castilleja grisea (CAGR) points considered current in relation to areas where fires have burned in the last 20 years (1999-2018, after the initiation of fire management), including number of fires in that time...... 49 Figure 13. Locations of Castilleja grisea (CAGR) points considered current in relation to areas where fires where severity data is known have burned (2007-2018). Severity categories 1, 2, and 3 have the potential to burn shrubs where they will not resprout; severity categories 4 and 5 have little to no effect on shrubs...... 50 Figure 14. Representation of locations of watersheds where no threats exist to Castilleja grisea (CAGR), a low level of threats exist to the watershed (threats could potentially affect <50% of the locations, individuals, or area within the watershed), or a moderate level of threats exist to the watershed (threats could potentially affect ≥50% of the locations, individuals, or area within the watershed). Threats identified include locations or

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individuals within 100 ft of a road or the AVMR, in the TARs, Impact Areas, and AVMA watersheds, and percent of the watershed area that burned once or >1 time in the past 20 years. Further, AVMA watersheds are considered to have a low threat level, whereas watersheds in the Impact Areas are assumed to have a moderate threat level...... 56 Figure 15. Current resiliency of Castilleja grisea (CAGR) (based on estimated number and distribution of individuals) by watershed...... 62 Figure 16. Resiliency estimates by watershed (based on number of individuals) currently as well as under each of our three scenarios. Extant watershed counts do not account for recruitment into new watersheds...... 70 Figure 17. Approximate boundaries of the 28 occurrences used in the 2013 downlisting rule (USFWS 2013); polygons represent the bounding geometry (minimum convex polygons) around the point locations and element occurrences used to define each occurrence, and the canyon names used to reference each occurrence are provided...... 90

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SECTION 1 – INTRODUCTION AND ANALYTICAL FRAMEWORK

The San Clemente Island Paintbrush (Castilleja grisea) is a subshrub in the broomrape family (Orobanchaceae) endemic to San Clemente Island (SCI). Castilleja grisea was federally listed as endangered in 1977 and was downlisted to threatened in 2013 (USFWS 2013, p. 45437). The Species Status Assessment (SSA) framework (USFWS 2016, entire) is intended to support 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 long-term viability. The intent is for the SSA Report to be easily updated as new information becomes available and to support all functions of the Endangered Species Program from Candidate Assessment to Consultations to Recovery. This SSA for Castilleja grisea is intended to provide an update on the species’ biological condition and level of viability. For the purpose of this assessment, we generally define viability as the ability of C. grisea to sustain populations in their natural ecosystem up through and beyond a biologically meaningful timeframe, in this case, 20 to 30 years. We chose 20 to 30 years because beyond 20 to 30 years, the level of uncertainty associated with the impacts of climate change (specifically, the persistence and timing of the fog layer; see Section 5.5) becomes very high, making predictions unreliable. The available climate model projections for SCI are uncertain, but the impacts are more likely to be minimal within a 20- to 30-year timeframe. Using the SSA framework (Figure 1), we consider what the species needs to maintain viability by characterizing the status of the species in terms of its resiliency, redundancy, and representation (Wolf et al. 2015, entire).

• Resiliency describes the ability of populations to withstand stochastic events (arising from random factors). We can measure resiliency based on metrics of population health; for example, recruitment versus mortality rates and population size. Highly resilient populations are better able to withstand disturbances such as random fluctuations in recruitment rates (demographic stochasticity), variations in rainfall (environmental stochasticity), or the effects of anthropogenic activities.

• Representation describes the ability of a species to adapt to changing environmental conditions. Representation can be measured by the breadth of genetic or environmental diversity within and among populations and gauges the probability that a species is capable of adapting to environmental changes. The more representation, or diversity, a species has, the more it is capable of adapting to changes (natural or human caused) in its environment. In the absence of species-specific genetic and ecological diversity information, we evaluate representation based on the extent and variability of habitat characteristics across the geographical range.

• Redundancy describes the ability of a species to withstand catastrophic events. Typically measured by the number of populations or individuals, their resiliency, and their distribution (and connectivity), redundancy gauges the probability that the species has a margin of safety to withstand or can bounce back from catastrophic events (such as a rare destructive natural event or episode involving many populations).

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Figure 1. Species Status Assessment Framework. From USFWS 2016.

1.1 Status of the Species Castilleja grisea was one of the first plant species to be listed pursuant to the Endangered Species Act (ESA). Many of the early plant listings were made on the basis of the species’ inclusion in a report to Congress on January 9, 1975, by the Secretary of the Smithsonian Institution (House Document No. 94-51 of the 94th Congress, 1st Session). That report was primarily comprised of a list of over 3,100 U.S. vascular plant taxa that the scientists who compiled it considered to be endangered, threatened, or possibly extinct. The Smithsonian report and the proposed rule to list C. grisea (41 FR 24523; USFWS 1977, p. 40685), however, did not include specific information regarding the ecology, demographics, or natural history of the species. The major threat to this taxon at the time of listing was herbivory and habitat destruction from non-native mammals but since removal of these animals in 1992, its abundance and distribution has increased such that C. grisea was downlisted to threatened in 2013 (USFWS 2013, p. 45437). The regulatory history of C. grisea is as follows:

• Castilleja grisea was listed as federally endangered on 11 August 1977 (USFWS 1977). • Castilleja grisea was listed as state endangered in April 1982 (CNDDB 2019). • A Recovery Plan for Channel Islands species, including Castilleja grisea, was finalized in 1984 (USFWS 1984).

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• 5-year status reviews were completed in 2007 (USFWS 2007) and 2012 (USFWS 2012). These status reviews recommended reclassification of Castilleja grisea from endangered to threatened. • On May 18, 2010, USFWS received a petition dated 13 May 2010, from the Pacific Legal Foundation to downlist Castilleja grisea from endangered to threatened under the ESA. • On 19 January 2011, a 90-day finding was published announcing the initiation of a status review of Castilleja grisea (USFWS 2011). • On 16 May 2012, a proposed rule to reclassify Castilleja grisea from Federally Endangered to Threatened was issued (USFWS 2012). • On 19 February 2013, Castilleja grisea was changed from California Rare Plant Rank 1B.2 to 1B.3 (Slakey et al. 2013) • On 26 July 2013, the final rule to reclassify Castilleja grisea from Federally Endangered to Threatened was published (USFWS 2013).

While most survey data used to support the analyses in this SSA were collected in 2011- 2013 before the 2013 downlisting rule (USFWS 2013), this SSA will differ from and build upon the 2013 downlisting rule by both reassessing the level of threats perceived in 2013, including incorporating new data on those threats and on the species’ response to threats, as well as assessing the data using different methods and following the SSA framework. Additional information relating this SSA’s methods and approach to that of the 2013 downlisting rule can be found in Appendix C.

SECTION 2 – SPECIES BIOLOGY

In this chapter, we provide biological information about Castilleja grisea, including its taxonomic history, morphological description, historical and current distribution and range, and known life history.

2.1 Taxonomy Castilleja grisea was first described by Dunkle (p. 31) in 1943. Munz (1958) later treated the taxon as a subspecies under C. hololeuca [C. hololeuca E. Greene subsp. grisea (Dunkle) Munz]. More recent analysis by Chuang and Heckard (1992, entire) placed C. hololeuca as a subspecies under C. lanata, leaving C. grisea as a distinct species (Muller 2005, p. 3). Previously assigned to the figwort family, Scrophulariaceae, the genus Castilleja was moved to Orobanchaceae in 2001 (Olmstead et al. 2001, p. 352). This family now includes all the hemiparastic taxa that were formerly in the Scrophulariaceae based on genetic evidence that the evolution of holoparasitism (obligate parasitism) was not a linear process but had occurred multiple times, and the split between the Scrophulariaceae and Orobanchaceae was not monophyletic (Young et al. 1999, p. 884). These changes are broadly accepted (Wetherwax et al. 2012, entire) and are reflected in the Federal Register (USFWS 2012, p. 29078).

Genetics Helenurm et al. (2005, p. 1223) used allozymes (proteins that are used as genetic markers) to determine the overall level of genetic variation and genetic structure of Castilleja grisea. Leaf tissue was sampled from 19 groups spanning the range of C. grisea on SCI.

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Seventeen to 55 individuals were haphazardly sampled from each group. The study found that genetic variation (number of alleles per locus, percent of loci that are polymorphic, and expected heterozygosity) within C. grisea is moderately high at both the species and group levels for an insular endemic plant, particularly given its history of rarity (Helenurm et al. 2005, p. 1225). This suggests C. grisea may have retained substantial genetic variation through the period of overgrazing and possibly suggests considerable recruitment from a seed bank, although we have no indications that the species supports a long-lived seed bank (see Section 2.5). Several characteristics of C. grisea, including sexual reproduction, a long-lived perennial herbaceous habit, late successional status, and an outcrossing, animal and/or insect-pollinated mating system, are associated with higher levels of genetic variation in plants. Consistent with an outcrossing breeding system, most of the genetic variation in C. grisea is within, rather than among, groups on the island (Helenurm et al. 2005, p. 1225). However, genetic diversity is distributed unevenly across sampled occurrences and no spatial relationship was found between occurrences with respect to specific genetic markers, suggesting that gene-flow occurs across distances (Helenurm et al. 2005, p. 1225).

2.2 Species Description Castilleja grisea is a highly branched perennial herb to subshrub. The species is endemic to SCI (Chuang and Heckard 1993, p. 1021) and is the only representative of the genus Castilleja found on the island (Helenurm et al. 2005, p. 1222). Castilleja grisea is typically 11.5 to 31.5 inches (29 to 80 cm) in height and covered with dense white, wooly hairs. Most Castilleja species have bisexual flowers disposed in terminal spikes. The flowers of C. grisea are yellow. Its leaves are alternate and linear, approximately 0.5 inch to 2 inches (1.3 to 5 cm) long with 0 to 3 lobes (Chuang and Heckard 1993, p. 1021). The fruit is an ovoid capsule, less than 0.5 inch long, containing approximately 150 seeds (Junak and Wilken 1998, p. 83). Castilleja grisea seeds are typically brown and less than 0.17 inch long. The seed coats are deeply netted, allowing the encapsulation of air, which may aid dispersal via water (Chuang and Heckard 1993, p. 1021; Muller and Junak 2011, p. 12). This reticulate seed coat, paired with the lightweight nature of the seeds, make them aerodynamic, which also may aid in dispersal, although seed dispersal mechanisms are unknown (Muller and Junak 2011, p. 16).

2.3 Range and Distribution Castilleja grisea is endemic to SCI, located 64 miles (103 km) west of San Diego, California, and the southernmost of the California Channel Islands (Figure 2). The island is approximately 56 square mi (145 square km, 36,073 acres, or 14,598 hectares) (Junak and Wilken 1998, p. 2) and is long and narrow: 21 mi (34 km) long by 1.5 mi (2.4 km) wide at the north end, and 4 mi (6.4 km) wide at the south end (USFWS 1984, p. 5). The island consists of a relatively broad open plateau that slopes gently to the west. Conspicuous marine terraces line the western slope of the island while steep escarpments drop precipitously to the rocky coastline on the eastern side along the southern 75%. Many canyons, some of which are up to 500 feet (152 meters) deep, dissect the southern part of the island. Mount Thirst, the highest point on the island, rises to approximately 1,965 feet (599 meters) (US Navy 2013a, p. 1.4). Average monthly temperatures range from 58°F (14°C) to 66°F (19°C), with a monthly maximum temperature of 72°F (27°C) in August and a monthly minimum of 51°F (10°C) in December (US Navy 2013a, p. 3.11). Average monthly relative humidity varies from 54% to 86% depending on location and time of year, and the island experiences dramatic fluctuations in annual rainfall, averaging 6.6

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inches (16.8 cm) (US Navy 2013a, pp. 3.11, 3.13). Precipitation is received mainly from November through April, with little from May through October. In addition to precipitation, fog drip during the typical dry season is a vital source of moisture to the SCI ecosystem (US Navy 2013a, pp. 3.9, 3.13).

Figure 2. Location of San Clemente Island in the southern Channel Islands off the coast of California.

Castilleja grisea is thought to have been relatively common on SCI in the 1930s, and subsequently declined as a result of unchecked grazing by introduced feral herbivores (Helenurm et al. 2005, p. 1222). The complete historical range of C. grisea on SCI is unknown because botanical studies were not completed before the plant’s decline. Herbarium records documented

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the species on the south and east sides of the island before the time of listing (California Consortium of Herbaria 2019, records for C. grisea). By 1963, C. grisea was reported as rare or occasional (Raven 1963, p. 337). Since the complete removal of feral ungulates from SCI by 1992, C. grisea has been detected across the southern two-thirds of the island (Keegan et al. 1994, p. 58; Junak and Wilken 1998, pp. 1– 416, GIS data; Junak 2006, pp. 1–176, GIS data; Tierra Data Inc. 2008, pp. 1–24, appendices and GIS data; SERG 2010a and 2010b, GIS data). The linear distance between the northernmost and southernmost occurrences is 15.2 mi (24.4 km). Some historical locations are unknown to be extant currently due to a lack of repeat survey data and unknown survey extents (see Section 2.6.1); additionally, there are 8 watersheds that historically had C. grisea in which the occupancy is currently unknown (see Section 2.6). However, the range has generally expanded over time, despite the potential loss of some of these areas (see Figure 6).

2.4 Habitat Castilleja grisea is often associated with two major vegetation types: Canyon woodland (which encompasses approximately 696 ac [282 ha]), and maritime desert scrub (which encompasses approximately 6,228 ac [2,520 ha]). Over time, the range of C. grisea has expanded, and it now occupies a broad range of habitats across the island (Figure 3). Thus, the general host-selection of C. grisea and the overall increase of host species on the island following the removal of feral browsers and grazers has likely aided recovery (Muller and Junak 2011, pp. 16–17). Castilleja grisea grows at elevations between 32 and 2,000 ft (10 and 365 m) (USFWS 2012, p. 29094). Aspect varies widely, but generally plants are found on flats and steep rocky slopes from 0-70 degrees (CNDDB 2019; US Navy 2017, pp. 11–24; Vanderplank et al. 2019, p. 5), and the species is found almost exclusively on non-clay soils and rocky outcrops (Figure 4) (Vanderplank et al. 2019, p. 5). Castilleja grisea can colonize disturbed areas, and the species likely has the potential for further range expansion on SCI (US Navy 2008a, p. 3.11–3.20; Vanderplank et al. 2019, p. 5). Suitable habitat appears to be more closely associated with soil-type than with vegetation community. Although not specifically mapped, exotic annual grasses and forbs are widespread across SCI (US Navy 2013a, pp.3.56–3.106) and certainly occur in habitat for Castilleja grisea (USFWS 2007, p. 6). The invasion of nonnative annual grasses on the island may have caused the greatest structural changes to C. grisea habitat, especially on the coastal terraces and in swales (USFWS 2007, p. 4-5). Nonetheless, many areas of non-clay and rocky soils remain uncolonized by C. grisea even though vegetation communities known to support this species are present (Figure 4).

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Figure 3.Vegetation types on SCI and locations of Castilleja grisea collected during 2011 and 2012 surveys. From Vanderplank et al. 2019.

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Figure 4. Castilleja grisea distribution from the 2011 and 2012 surveys and soil types. From Vanderplank et al. 2019.

2.5 Life History All members of the genus Castilleja are considered hemiparasitic, meaning their roots have haustorial attachments (specialized absorbing structures) that penetrate the host plant’s root tissue, forming an organic bridge with the host (Heckard 1962, p. 27). While plants are capable of photosynthesis and can exist without a host, they are able to derive water, nutrients, and photosynthates from a host plant if present (Heckard 1962, p. 25). In greenhouse studies, seedlings of Castilleja grisea grown in the absence of host plants did not perform well and died shortly after germination, suggesting that host plants are important for this species (Junak and Wilken 1998, p. 84). Greenhouse studies also have shown that overall performance and fecundity of parasitic plants are usually higher with a host than without one (Heckard 1962, p. 29; Atsatt

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and Strong 1970, p. 280), and Adler (2003, p. 2087) found that parasitic individuals of Castilleja indivisa attract more pollinators and produce more seeds than non-parasitic individuals. In field settings, species of Castilleja tend to establish haustorial connections with one or more hosts (Heckard 1962, p. 27; Atsatt and Strong 1970, p. 280). Parasitism in Castilleja seems to be a generalist phenomenon as members of the genus appear to form haustorial connections with a range of plant species from a wide range of families, including Asteraceae, Fabaceae, Polygonaceae, Poaceae, and Rosaceae (Heckard 1962, p. 28; Atsatt and Strong 1970, p. 280; Marvier 1996, p. 1399; Adler 2002, p. 2704; Adler 2003, p. 2086; Muller 2005, p. 4). Although studies to verify host-connections have not been done, numerous plant species are associated with C. grisea including, but not limited to: Artemisia californica, Atriplex californica, Bergerocactus emoryi, Bromus madritensis rubens, Calystegia macrostegia subsp.amplissima, Dichelostemma capitatum, Dudleya virens virens, Encelia californica, Constancea nevinii, Gambelia speciosa, Hemizonia clementina, Isocoma menziesii, Lotus argophyllus omithopus, Lycium californicum, Mirabilis californica, Opuntia littoralis, Opuntia oricola, Opuntia prolifera, Rhus integrifolia, and Senecio lyonii (Junak and Wilken 1998, p. 82) and Nassella pulchra (R. N. Muller, pers. comm., 2009 in USFWS 2012). The generalist host-selection of C. grisea likely aided recovery of this species as the vegetation recovered following the removal of feral browsers and grazers (Muller and Junak 2011, p. 16-17).

Reproduction Castilleja grisea typically flowers between February and May, producing yellow bisexual flowers (Chuang and Heckard 1993, pp. 1016–1024; US Navy 2013a, pp. 3–203). Castilleja grisea is likely self-incompatible (unable to produce viable seed through self-fertilization), as observed in other species of the genus (Carpenter 1983, p. 218; Junak and Wilken 1998, p. 84). The relevant statistics from a population genetic study were consistent with an outcrossing breeding system (Helenurm et al. 2005, p. 1225). Castilleja grisea is most closely related to, and shares floral traits with, other species in the genus primarily adapted for bee pollination (Chuang and Heckard 1991, p. 658), but both insect and hummingbird pollination of Castilleja have been reported (Grant 1994, p. 10409; Junak and Wilken 1998, p. 84). A single bee from the family Andrenidae, covered in pollen, was collected from flowering C. grisea in Canchalagua Canyon on SCI (Howe 2009, pers. comm in USFWS 2012). Eight bee species in six genera and 14 fly species in four genera were observed visiting flowers (SERG 2015b, p. 11). Putative pollinators were similar in their species diversity across sites, but pollinator abundance varied considerably. Putative floral predators include caterpillars, thrips, and aphids (SERG 2015b, p. 10). The fruit of Castilleja grisea is an ovoid capsule, less than 0.5 in (1.27 cm) long, containing approximately 150 seeds (Junak and Wilken 1998, pp. 82–83). Under natural conditions, plants typically produce 9 to 14 fruits per inflorescence. Among four populations of C. grisea examined, Junak and Wilken (1998, pp. 83–84) found that 67 to 71 percent of all flowers produced fruit, and seed production per plant, although high, was highly variable, suggesting that C. grisea may either be self-incompatible and/or strongly dependent upon a pollinator. The seeds of Castilleja grisea are small (less than 0.5 mm in length and weighing less than 0.001 g) with deeply netted seed-coats which may create air pockets and facilitate either atmospheric- or water-dispersal (Muller and Junak 2011, p. 12). These small seeds have neither a reserve of stored carbohydrate to facilitate physiological dormancy nor a seed-coat capable of imparting physical dormancy, and germination studies did not detect dormancy in closely-related taxa (Muller and Junak 2011, p. 13). During attempts to propagate C. grisea plants from seed, no

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significant differences were found between seed viability (79.5 to 85 percent) and germination (68.3 to 76.7 percent), suggesting a lack of dormancy (Junak and Wilken 1998, p. 84). However, a single accession of C. grisea had a 97% germination rate after 18 years in storage, suggesting that seed longevity is very high in this taxon (Birker 2017, pers. comm. in Vanderplank et al. 2019). In the field, C. grisea seeds typically germinate in the spring following seed-set as temperatures begin to warm (Muller 2005, p. 17). Factors inhibiting germination of C. grisea may be a lack of moisture in habitat areas at the time that seeds are disseminated and cold fall and winter temperatures that occur when moisture does arrive (Muller and Junak 2011, p. 13).

Life Span The life span of individual plants of this species is unknown; however, the life span of perennial herbaceous (i.e., fibrous, non-woody) plants differs from woody perennial plants in that the life-span is shortened following flowering. Perennial herbaceous plants may exhibit high variability in both demographic state (reproductive adult, dormant adult, seed, non-reproductive recruit from seed, clonal adult) and in rates of change in these demographic states within any given occurrence or population (Harper 1977, pp. 549–564). Another herbaceous, perennial subshrub endemic to the northern California Channel Islands, Castilleja mollis (soft-leaved paintbrush), forms brittle stems that support leaves only during the growing season, which is typically January until late June, and old stems are replaced by new growth each year; the population persists through both clonal growth and sexual reproduction (McEachern et al. 2009, pp.1567, 1582). A similar growth pattern with respect to die-back and annual regrowth has been observed for another herbaceous, perennial subshrub, C. levisecta (golden paintbrush) (USFWS 2009, p. II-24, 27). The lifespan of Castilleja levisecta has been documented to be 5–6 years (Dunwiddie et al. 2001, p. 161). Although the lifespan of Castilleja grisea is unknown, its larger stature and woodier habit suggest it may be longer lived, which would be consistent with an estimated lifespan of 5–15 years based on observations made during repeat visits to occupied sites (Munson 2019, pers. comm.). Based on life-history, persistence of interbreeding groups of plants (occurrences) may depend upon frequent production of seed (Dunwidde et al. 2001, p. 161). In their field- assessment of population demography, Muller and Junak found that individual locations of Castilleja grisea were highly dynamic with some showing little recruitment of new individuals, others showing substantial recruitment, and still others showing significant mortality of older plants without recruitment of new plants (2010, p. 42). However, Muller and Junak (2010, p. 42) considered that the growth and spread of C. grisea occurs entirely by seed as they found no evidence of clonal growth. Although seeds may be morphologically adapted for longer distance dispersal, the authors concluded that wide-spread dissemination of seeds appears to be limited and establishment of new population centers infrequent; rather, growth is primarily by expansion of existing populations from plants that emerged from the soil seed-bank following removal of feral herbivores or from plants that survived those impacts (Muller and Junak 2011, p. 42). However, the increase in Castilleja grisea’s range, along with the discovery of new individuals along trails or near buildings that people frequent (O’Connor 2019, pers. comm.), suggests that the establishment of new population centers may be relatively common.

Fire tolerance The effects of fire on population dynamics of Castilleja grisea are mostly unknown, although plants are known to survive fires and have expanded in areas that have previously burned (US Navy 1996, pp. 5–2; Tierra Data Inc. 2005, p. 80; Vanderplank et al. 2019, p. 13).

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Although not adapted to fire (i.e., lacking specialized structures or physiological processes which enable post-fire regeneration), occurrences of C. grisea are likely resilient to occasional fires based on phylogeny (Muller and Junak 2011, p. 16; US Navy 2013a, p. 3.204; Tierra Data Inc. 2005, p. 80). There is uncertainty in the full effect of fire on the species; while severe fires have been shown to kill individuals and reduce the population substantially (see Section 4.4), fire may also be useful for establishment (Muller and Junak 2011, p. 16). It is thought that fire promotes seed germination; however, seed germination was seemingly low following a high severity fire (see Section 4.4). Individual plant-response (survival, reproductive output, germination and recruitment from seed) to burning was studied for C. levisecta, and results were highly variable between plots and over time (Dunwidde et al. 2001, pp. 167–172). In general, burning did not increase plant mortality within a study-plot when averaged over several years, and post-fire conditions seemed to facilitate recruitment and improve vigor of plants that survived. These results could be the effect of burn-ash on soil nutrients or a reduction in competing vegetation. Observed increases in abundance and vigor were realized for 6 to 11 years following fire, and then the study populations declined dramatically (Dunwidde et al. 2001, p. 171). The authors noted that the widely differing trends and variability in measured responses suggest that burn effects on paintbrush can vary considerably across a site and vary in terms of magnitude and longevity (Dunwidde et al. 2001, p. 171). No information about the severity of fire within study-plots was provided. Fire and its potential impacts will be discussed in more detail in Section 4.4.

2.6 Population trends and abundance Tracking the population size and abundance of Castilleja grisea has been complicated by the difficulty of monitoring the species on a routine basis due to terrain, access restrictions implemented to minimize the risk of unexploded ordnance, and the level of effort required to survey a large area during a limited survey window. While much occurrence data exist for C. grisea over time, few comprehensive surveys have been attempted or conducted. Due to the constraints noted above, no survey has covered the entirety of the island. Survey areas have varied, and recorded observations have often been inconsistent and opportunistic, focused on capturing the distribution of the species, both during and outside of formal surveys. Survey data and opportunistic observation data collected by the US Navy consists of counts of individuals within “contiguous biologically relevant clusters that are unbroken within a line of sight and do not include any obvious barriers to dispersal, pollination, or recruitment” (Vanderplank et al. 2019, p. 7). Thus, survey data consist of a count of the number of individuals at each of these locations, represented as a single point in space. As resources, terrain, and access limitations preclude the feasibility of an exhaustive survey of all 36,073 acres (14,598 hectares) on the island (Figure 5), the precise abundance of this taxon in any year or set of years is difficult to determine. Because we do not know the extent or intensity of any of these historical survey efforts, we cannot estimate the number of previously undetected individuals (Vanderplank et al. 2019, p. 10). To limit the possibility of double- counting when looking at individuals counted over time, we compared the results of individual surveys rather than combining surveys, as it is unknown if or to what extent survey extents overlapped. Watersheds have been suggested by the Navy as a means of delineating the population into segments in order to monitor trends in the number of Castilleja grisea individuals in these different segments in the future. Because every point on the island can be ascribed to a

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watershed, watersheds can serve as a unit for monitoring and management. Watersheds may also be meaningful biologically by influencing the dispersal of seeds; however, while it seems probable that new recruitment would be more likely to occur in an occupied watershed than an unoccupied one due to seed dispersal, this is speculation. Therefore, for consistency and in an attempt to standardize C. grisea data, we will discuss the current population of C. grisea, general trends over time, and future population estimates in terms of the documented number of individuals from various survey years and numbers of occupied watersheds. Comparing the results of individual surveys/studies of Castilleja grisea on SCI shows a general increase in the number of C. grisea detected in each subsequent survey (Table 1). The C. grisea population was estimated at approximately 1,000 individuals in 1984 (USFWS 1984, p. 58). Comprehensive surveys began in 1996 and 1997, which documented 77 locations comprising over 3,500 individual plants (Junak and Wilken 1998, p. 82). These locations ranged from isolated individuals to populations of 600 individuals. Surveys by Junak (2006) from 2003 through 2006 documented 198 locations and estimated 9,718 individuals (p. 47). These locations ranged from isolated plants to populations with 1,400 individuals, for an average population size of 49 individuals. The 2011 and 2012 Navy survey represents the most recent extensive survey data for C. grisea. During the 2011 and 2012 survey, 336 locations and 31,694 individuals of C. grisea were mapped (Vanderplank et al. 2019, p. 7) (Table 1). We assessed the number of watersheds documented as occupied over time, and found that watersheds observed to be occupied in a given decade have increased, from 15 between 1980 and 1989, to 75 known from between 2010 and 2014 (Figure 5, Table 2). These watershed counts represent only those with documented records of Castilleja grisea from that decade and do not account for watersheds that may have remained populated but were not surveyed in subsequent decades.

Table 1.Surveyed number of Castilleja grisea individuals during various survey years (USFWS 1984, p. 58; Junak and Wilken 1998, p. 82; Junak 2006, p. 47; Vanderplank et al. 2019, p. 7). Survey extents are unknown. Survey year Individuals 1984 1,000 1996-1997 3,500 2003-2006 9,718 2011-2012 31,694

Table 2. Number of watersheds known to be occupied by Castilleja grisea recorded by decade. These represent only surveyed watersheds where C. grisea were found in that decade and do not account for watersheds that may have remained populated but were not surveyed in subsequent decades. Decade Occupied Watersheds 1980-1989 15 1990-1999 16 2000-2009 56 2010-2014 75

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Despite the inconsistencies in the survey data, the data indicate that the number of individuals and the range of Castilleja grisea have increased over time (Table 1, Table 2, Figure 5), although the rate of increase and true population size in any year is unknown. The 2011 and 2012 surveys demonstrate a 30-fold increase in the number of individuals documented in 1984.

Figure 5. Distribution of locations of Castilleja grisea (CAGR) recorded per decade, with occupied watersheds in gray. Known locations occupied 15 watersheds between 1980 and 1989, 16 watersheds between 1990 and 1999, 56 watersheds between 2000 and 2009, and 75 watersheds between 2010 and

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2014. Only records documented in each decade are shown, though they may have remained extant in subsequent decades when they were not surveyed or located.

2.6.1. Current distribution Since no existing singular dataset or survey effort has been comprehensive enough to provide an estimate of the current distribution and abundance of Castilleja grisea across its entire range on SCI, to describe the current condition of the species for the purposes of this document, we first defined what will be considered the current distribution. While the 2011 and 2012 surveys represent the most extensive and recent surveys to date, these surveys alone likely do not represent the full distribution of C. grisea on the island. Like the rest of the survey data, the full extent of the survey area from 2011 and 2012 is not known because areas within which plants were not found were not documented, but these surveys did not cover the entirety of the island due to the constraints described in Section 2.6 above. Available data consist only of presence data, with no known corresponding absence data. Additional survey data from 1980 through 2014 include additional locations not documented in 2011 and 2012, some of which are likely still extant. For instance, 2005 data include locations from within Impact Area I, which has not been accessible since 2007 due to a change in policy associated with unexploded ordnance safety issues. In 2005, 58 locations and 1,231 individuals were documented in Impact Area I, mainly within Horse Beach Canyon (USFWS 2019, GIS data). The Environmental Impact Statement (EIS) (US Navy 2008a, p. D-19) reports 2,034 individuals, noting that these locations were generally away from targets where topography shielded them from direct hits by ordnance. They further noted that the species had been increasing in abundance despite the ongoing use of live ordnance (US Navy 2008a, p. D-19); thus, many of these locations, and locations from elsewhere on the island, likely still persist. Therefore, we developed a rule set to conservatively define the current distribution and abundance of Castilleja grisea. To ensure we were basing estimates on the most recent and robust dataset, we used the 2011 and 2012 survey points and then added point locations based on our set of rules. First, we did not want to go back too far in time and assume a population was still present when it might not be. Second, experts concurred that locations of C. grisea recorded as long as 15 years ago are likely to persist (Munson 2019 pers. comm.; O’Connor 2019 pers comm). Therefore, we applied the following criteria to the additional survey data to establish a current estimated distribution for C. grisea. The estimate of current distribution was made by including some data collection made prior and subsequent to the 2011 and 2012 surveys, that met the following conditions: 1) Includes count of individuals at the point and year collected. 2) Was recorded within the past 15 years (2004–present). 3) Does not occur within 50 m of a 2011 or 2012 survey point. 4) Does not occur within 50 m of a retained survey point from 2013 or 2014 if it is older than that point. 5) Does not occur within 100 m of a retained survey point from 2005-2010 if it is older than that point. We took the following steps to map this distribution: 1) We buffered the 2011 and 2012 data points by 50 m then deleted all points from other years that fell within these buffers. 2) We buffered the remaining 2014 data points by 50 m and deleted all remaining points that fell within these buffers.

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3) We repeated step 2 with the 2013 data. 4) We then buffered the remaining 2010 data points by 100 m and deleted all remaining points that fell within the buffers. 5) We repeated this process with the 2009, then 2008, 2007, 2006, 2005, and 2004 data, in that order. Use of this methodology is based the following assumptions: 1) Points recorded in the same year are considered separate, regardless of separation distance. 2) Recorded point locations may be inaccurate up to 50 m for newer points (2011 through 2014) and 100 m for older points (2010 and older), so to conservatively avoid double counting, we selected the more recent point if two points fell within these distances of each other.

This yielded 601 locations totaling 48,181 individuals occupying 87 watersheds (Figure 6), which we estimate to be the current abundance and distribution of Castilleja grisea. While we acknowledge that these numbers may not be exact due to mortality or expansion since these counts were completed, these data represent the best available information on the species and should approximate reality. We assume that a small percentage of these point locations have been completely extirpated, and those that may have been lost could have been replaced by unknown locations. Further, count numbers should also be approximate, as we expect mortality to be made up for by expansion over time in the absence of additional threats. A fire severe enough to affect shrubs such as Castilleja grisea occurred in 2017 along the eastern escarpment in part of SHOBA after collection of this data; post-fire monitoring has indicated that many plants survived, but their numbers may have decreased. This will be further explored and accounted for in Section 5; however, while we expect the distribution is the same, a decrease in population numbers in this region is not portrayed in Figure 6. It is important to note that this distribution overlaps almost completely with the 28 occurrences identified in the 2013 listing rule (Figure 17 in Appendix C); the current distribution, as we define it here, is missing a few points that are older than 2004 but includes some new points from 2013 and 2014 not included in the listing rule. The 28 occurrences listed in the 2013 rule included all known survey data, including historical data from 1979. Without repeated survey data in some of those locations, it is unknown whether individuals observed 40 years ago still persist. Compared to the historical distribution, there are 8 watersheds that were once occupied that are no longer considered occupied (Figure 6).

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Figure 6. Distribution of Castilleja grisea considered current as per methodology described in Section 2.6, with individuals per location and occupied watersheds indicated in dark gray. Historical locations are shown as gray dots, and historically occupied watersheds are in light gray. Occupation at these historical points and within these historical watersheds is unknown, but they are not considered occupied for this SSA.

SECTION 3 – INDIVIDUAL AND SPECIES NEEDS

In this section we synthesize the information in the preceding sections to highlight the overall resource-needs of the species. Typically, we assess needs at the individual and population

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levels and then finally at the species level, and we consider that the effects are cumulative: survival of individual plants contributes to survival of the cohort of plants within the area in which it occurs which, in turn, contributes to the survival and persistence of the population and ultimately, the species. We consider that the locations of Castilleja grisea on SCI constitutes a single population defined as a group of interbreeding individuals that produce offspring (Primack 1995, p. 12-13), rather than a species comprised of multiple, but distinct, populations. There are few obvious natural divisions between locations across the range of the species (USFWS 2013, p. 45437) and this conclusion is supported by an assessment of population genetic diversity mentioned above. We do, however, assess resource-needs by location (spatially distinct localities) given variability in habitat conditions and military operations across SCI. Hence, we consider resource-needs at the group-level by considering the separate locations grouped by watershed. If the needs of some number of individuals in a population are being met, allowing for an adequate population size and a sufficient rate of growth, then that population will likely have sufficient resiliency. The number of resilient populations, their size, distribution, and their level of connectivity can be used as a measure of the species’ level of redundancy relative to potential catastrophes. Similarly, the breadth of genetic or environmental diversity within and among populations can be used as a measure of the species’ level of representation. Thus, for the species to sustain populations in the wild over time and be viable, the populations need to be able to withstand stochastic events (to have resiliency), and the species as a whole needs to be able to withstand catastrophic events (to have redundancy) and to adapt to changing environmental conditions (to have representation). For the purposes of this report, we define viability as the ability of the species to sustain itself in the wild over time. We describe the species’ needs at the individual, watershed (population segment), and species’ levels in terms of resiliency, redundancy, and representation.

3.1 Population Resiliency For Castilleja grisea to maintain viability, its population or some portion thereof must be resilient. Stochastic factors that have the potential to affect C. grisea include drought, erosion, and fires. Other factors that influence the resiliency of the C. grisea population include ecological integrity of the plant community, population size, and dispersal ability. Influencing those factors are elements of C. grisea ecology that determine whether the population can grow to maximize habitat occupancy, thereby increasing resiliency of populations (Figure 7). These factors and habitat elements are discussed below. Assuming that these factors influence the number of individuals that can or will occupy available habitat on the island, we will use estimated population size (estimated number of individuals based on count data from our distribution considered current) as our measure to estimate resiliency.

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Figure 7. Habitat and population factors that influence the viability of Castilleja grisea throughout its range.

3.1.1 Individual Level At the individual level, Castilleja grisea require non-clay or other suitable soil, a host plant, pollinators, and habitat conditions that include adequate water, sunlight, and nutrients, with limited natural or anthropogenic destructive disturbance. As mentioned, we have no demographic information (germination fraction of seeds, proportional survival to reproduction, life span) to inform our understanding of the fitness of individual C. grisea plants. Anecdotal reports provide inferences about life-history and fitness (as cited in Section 2.5). It would seem that there are few, if any, intrinsic factors limiting individual plant growth and development of C. grisea (e.g., no evidence of genetic stochasticity having occurred). Extrinsic factors affecting individual fitness of plants could include excessive thatch or dense vegetation that reduces or precludes successful germination, weather conditions that do not favor germination before seeds become non-viable, and/or a lack of pollinator service that precludes successful reproduction. Germination and recruitment may be enhanced by occasional fire. However, post-fire monitoring has been conducted opportunistically following accidental fires and does not allow for an assessment of the response of Castilleja grisea to different fire severities over different time intervals. Further, reduced fitness of individuals with regards to seed-set or seed-viability may occur, but at an unknown level of significance. Field observations of low recruitment rates at some locations (Muller and Junak 2011, p. 42) and morphological indicators of non-dormancy in seeds have not been further documented but may indicate that we do not fully understand the forces that may have affected demographic rates of Castilleja grisea following the release from grazing-pressure. The cause of any potential reduced fitness of individuals in some areas is unknown.

3.1. 2 Population Segment (Watershed) Level Within a watershed, habitat must be maintained to support a sufficiently large number of individuals needed for persistence, although that number is unknown. Habitat features must be sufficiently contiguous or absent dispersal barriers such that necessary levels of pollination and seed set required for population dispersal and gene-flow within each watershed are achieved to

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maintain sufficient levels of genetic diversity to preclude deleterious effects to the population from inbreeding depression and genetic drift (Ellstrand and Elam 1993, entire). However, the necessary levels of dispersal and gene flow are unknown for this species. No barriers to the movement of pollinators (for gene flow) or dispersal events appear to exist within watersheds. The influence of stochastic variation in recruitment and mortality rates is much greater for small populations than large ones. Stochastic variation in demographic rates causes small populations to fluctuate randomly in size. In general, the smaller the population, the greater the probability that fluctuations will lead to extinction. There are also genetic concerns with small populations, including genetic drift and inbreeding depression. Small populations have low resilience, leaving them particularly vulnerable to stochastic events. While much of the island is composed of the vegetation communities and soil types thought to be potential habitat for this species, additional habitat limitations may exist that are currently unknown. The degree to which habitat is unfragmented and the suitability of available unoccupied habitat can help determine dispersal-success, which then influences gene flow, local adaptation, extinction risk, and the potential for organisms to move in response to a changing climate (Taylor et al. 1993, p. 572).

3.2 Species Redundancy and Representation 3.2.1 Species Level For the species to be viable, there must be adequate redundancy (suitable number and distribution of individuals) to allow the species to withstand catastrophic events. Redundancy improves with increasing numbers of occupied watersheds and with increasing numbers of individuals in each. Habitat for Castilleja grisea must be sufficiently contiguous or absent dispersal barriers such that necessary levels of population dispersal and gene-flow can occur among watersheds to maintain sufficient levels of genetic diversity (Ellstrand and Elam 1993, entire). This species will be most viable by occupying a range of watersheds in multiple habitats across the island. For instance, by occupying both the western and eastern sides of the island, which have differing moisture patterns, the species might be buffered from a localized catastrophic impact, such as a severe fire, or an island-wide catastrophic impact such as a prolonged drought, which could affect C. grisea on the eastern and western sides of the island differently due to differences in soil, slope, insolation, fog, rainfall, or other variables. Proximity of other individuals in other occupied watersheds will allow gene flow among watersheds and individuals and improve the chances of dispersal to new locations or across watersheds, which would allow the species to persist and become reestablished after catastrophes. Again, while much of the island seems habitable to this species, additional habitat limitations may exist that are currently unknown. No barriers to the movement of pollinators (for gene flow) or dispersal appear to exist on SCI, although terrain may favor recruitment within rather than across watersheds. Also for species viability, there must be adequate representation (genetic and environmental diversity) to allow the species to adapt to changing environmental conditions. Representation improves with increased genetic diversity and/or diverse environmental conditions within and among populations. Results from the population genetics assay suggest that diversity may have been retained over time in the soil seed bank. This may have occurred as plants that persisted in areas that escaped grazing pressure retained genetic diversity through outcrossing. In addition to genetic data, adequate representation for this species would be indicated by the population being distributed throughout multiple habitat types and across

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multiple elevations, indicating that the species is adapted to these different environmental and habitat conditions.

SECTION 4 – FACTORS INFLUENCING VIABILITY

The following discussion provides a summary of the factors that are affecting or could be affecting the current and future condition of the Castilleja grisea throughout some or all of its range. The current habitat conditions for Castilleja grisea on SCI are the result of historical land use practices. SCI was used legally and illegally for sheep ranching, cattle ranching, goat grazing, and pig farming (USFWS 2012, p. 29-91, US Navy 2013a, p. 2-3). Goats and sheep were introduced early by the Europeans, and cattle, pigs, and mule deer were introduced in the 1950s and 1960s (US Navy 2013a, p. 3-185). These non-native herbivores greatly changed the vegetation of SCI and were cited in the final rule (USFWS 1977, p. 40863) for the listing of C. grisea as the main cause of this species’ decline. Sheep were removed from the island in the 1930s, but pigs were not completely eradicated until around 1990 and feral goats were removed by 1992 (Keegan et al. 1994, p. 58; USFWS 2012, p. 29093). Although C. grisea may not have been a primary target of the mammalian herbivores, overgrazing and browsing probably led to the direct loss of plants through trampling and rooting. These grazing, browsing, and rooting animals also altered the habitat by creating trail networks with bare, compacted soil. Overgrazing, erosion, and other impacts to the vegetation led to severe habitat degradation and loss of suitable habitat that likely curtailed the range of C. grisea and other endemic plants on the island (USFWS 1997, p. 42697). The current distribution of Castilleja grisea is undoubtedly a product of topographical features that made certain areas inaccessible to goats and therefore provided refugia for C. grisea to survive the intense browsing. Further, seeds may have survived in the soil seed bank in other areas of the island, and together, these refugia determined the pattern of C. grisea’s expansion and recolonization of the island. At listing, nonnative herbivores were the primary threat to Castilleja grisea (USFWS 1977, p. 40682, Keegan et al. 1994, p. 58). As a result of their removal, habitat conditions improved and led to changes in the cover of native and nonnative plants on the island, further evidenced by the increases in C. grisea and several other threatened and endangered species since the feral animals were removed (Uyeda et al. 2019, pp. 6, 22, 30). In the absence of the primary threat, additional threats to C. grisea that have been identified include: (1) land use, (2) erosion, (3) nonnative plants, (4) fire and fire management, and (5) climate change (Figure 8). We discuss the impacts of these remaining threats that may affect C. grisea or its habitat and how management efforts are working to minimize these threats. We provide general information on each threat in this discussion; more specific information on the current status of C. grisea in relation to these threats will be provided in Section 5.

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Figure 8. Factors that affect population resiliency in Castilleja grisea. This is not a complete compilation but represents the most important factors.

We assess threats to individuals of Castilleja grisea within each occupied watershed.

4.1 Land use (direct effects) SCI is owned by the U.S. Department of the Navy (Navy) and, with its associated offshore range complex, the island is the primary maritime training area for the Pacific Fleet and Sea Air and Land Teams (SEALs) (USFWS 2012, p. 29078). The island also supports training by the U.S. Marine Corps, the U.S. Air Force, the U.S. Army, and other military organizations. As the western most training range in the eastern Pacific Basin, where training operations are performed prior to troop deployments, portions of the island receive intensive use by the military (US Navy 2008a, p. 2.2). Various training activities occur within particular land use designations and training areas on the island. Military training activities within some of these training areas can involve the movement of vehicles and troops over the landscape and can include live munitions fire, incendiary devices, demolitions, and bombardment (Table 3). The direct effects of military training and other land uses will be discussed here; indirect effects, such as erosion and fire, will be discussed in separate sections below. SCI supports 20 terrestrial Training Areas and Ranges (TARs), three Assault Vehicle Maneuver Areas (AVMAs), and the Infantry Operations Area (IOA). TARs are operating areas that support demolition, over-the-beach, and tactical ingress and egress training for Naval Special Warfare personnel (US Navy 2008a, p. 2.7). AVMAs are designated for off-road vehicle use, including tracked vehicles, and the IOA is designated for dispersed foot traffic by military units in support of a battalion-sized landing (US Navy 2008a, p. 2.37) (Figure 9). While the IOA is a broad designated area for foot traffic, use has been, and is anticipated to continue to be, concentrated around the AVMR (Artillery Vehicle Maneuver Road). Soldiers fan out from but

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move in concert with artillery vehicles, which are restricted to the AVMAs and AVMR; accordingly, foot traffic has occurred predominantly within 50 feet of the AVMR, within the IOA (Booker 2019, pers. comm.). Other major potential impacts (artillery firing points [AFPs] and bivouacking) within the IOA also occur near the road (USFWS 2008, pp. 42, 164). This buffer around the AVMR makes up less than 1% of the IOA (Table 3). Additionally, six near-shore Special Warfare Training Areas (SWATs) have been designated on and around SCI (Figure 9). These large areas encompass land, water, and associated airspace. They are used as ingress and egress of small troops to specific TARs. Basic and advanced special operations training is conducted within these areas by Navy and Marine Corps units (US Navy 2013a, p. 2.10; US Navy 2008a, p. 2.7). Thus, impacts from training in these areas is infrequent and dispersed (Booker 2019, pers. comm.). The Shore Bombardment Area (SHOBA) is the largest terrestrial training area and supports a diversity of military training (including Anti-Surface Warfare, Amphibious Warfare, Naval Special Warfare, Bombing Exercises, and Combat Search and Rescue) (Figure 9). SHOBA occupies roughly the southern third of the island and is approximately 13,824 ac (5,594 ha) (US Navy 2008a: Tables 2–7; US Navy 2009, p. 2–4). Areas of intensive use within SHOBA include the two Impact Areas and three TARs, which lie within the Impact Areas. Impact Areas support naval gun firing, artillery firing, and air-to-ground bombing (US Navy 2008a, p. 2–7; US Navy 2013a, p. 2–8). Collectively, the Impact Areas and TARs within SHOBA encompass 3,400 acres [1,376 ha], which amounts to 24.6% of the area within SHOBA. Much of the remainder of SHOBA serves as a surface danger zone (buffer) around Impact Areas I and II, and 59% of SHOBA is not within the (IOA), Impact Areas, or a TAR and therefore not subject to any direct training activities. Some areas, particularly the escarpment along the eastern coast, have limited training value because precipitous terrain hinders ground access. The Impact Areas sustain live fire, which is a recurrent source of fires. Most fires are of low severity, which does not have a strong negative impact to shrubs. Fuel breaks are installed each year prior to fire season to help prevent spread of fire to areas outside of the Impact Areas for protection of natural resources. Fire will be discussed in greater detail in section 5.4. Because parts of SHOBA are used for bombardment, access to this area is restricted for nonmilitary personnel on days when bombing is occurring. Individuals conducting surveys or working on invasive species control projects are granted access to areas outside of the Impact Areas within SHOBA when military activities requiring exclusive use are not occurring. Because of the frequency of training, access to SHOBA can be restricted for periods of time. The IOA encompasses approximately 25% of the island, the Impact Areas encompass about 9.4% of the island, TARs, which in places overlap the IOA, Impact Areas, and AVMAs, cover 5.5 % of the island, and the AVMAs, which fall entirely within the IOA, encompass about 3% of the island (US Navy 2008a, pp. 2.17, 2.45; US Navy 2008b, pp. 3.11–3.52) (Table 3, Figure 9). Altogether, 34.8% of the island’s area is located in one of these training areas, although training does not occur uniformly within each; much of the island is void of any infrastructure. In comparison to many other military installations, there is a very low visual presence of the military on SCI (McFarland 2019, pers. obs.). In 2008, the Southern California Range Complex Final Environmental Impact Statement/Overseas Environmental Impact Statement (EIS/OEIS) (US Navy 2008a) and the accompanying Biological Opinion: San Clemente Island Military Operations and Fire Management Plan (BO) (USFWS 2008) were finalized, and together, these documents allowed for increased training at SCI and addressed obligations for fire management and listed species

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management (US Navy 2008a, p. 2.1–2.52). To avoid underestimating impacts and to ensure adequate coverage under all applicable federal laws and regulations, including but not limited to the National Environmental Policy Act (NEPA), the ESA, and the Clean Water Act, the analyses considered a training tempo that was at the highest reasonably anticipated level. It is unlikely that the maximum operational tempo will be reached for all activities simultaneously because overseas deployments, availability of personnel and assets, planning and construction timelines, development of platforms and systems, and other factors can lower the tempo and/or delay implementation; however, it was necessary to analyze the potential impacts of such a tempo (O’Connor pers. comm., 2019). Training began to increase soon after issuance of the 2008 BO and Record of Decision (ROD) for the EIS, but increases in some types of training, particularly those that required acquisition of assets, development of platforms and systems, and/or planning and construction, have increased more gradually, and some have not reached the operational tempo in the documents. One example of the latter type of activity is the battalion-sized landing planned to occur within the Assault Vehicle Maneuver Corridor, which will be discussed further in Section 4.2. In contrast to the AVMAs, the TARs (all except TAR 19) were fully developed and utilized shortly after issuance of the ROD and have been in use since. TARs 10 and 17 were of particular concern due their location on the west side of the island within high-density, federally-listed San Clemente Bell’s sparrow (Artemisiospiza belli clementeae) habitat and the introduction of new ignition sources to the west shore (O’Connor 2019, pers. comm.). However, after approximately 11 years of use, no fires have occurred in either of these TARs, and there to not appear to be training impacts to the Bell’s sparrow in these areas (Meiman et al. 2018, p. 39).

Table 3. Summary of training areas, their size, use, and the threats to Castilleja grisea within each. Size Training area (Acres) % of island Use Threat vehicular Soil erosion, trampling, devegetation AVMAs (3) 1,060.5 2.9% maneuvering (habitat removal) IOA 8,827.6 24.5% dispersed foot traffic Trampling, soil erosion Varies by TAR: Varies by TAR, but limited to TARs (20) 1,968.2 5.5% demolition, small trampling, localized ground (terrestrial only) arms, combat, etc. disturbance Devegetation (habitat removal), fires Impact Areas (2) 3,399.7 9.4% bombing, live fire (accounted for separately)

Range schedulers are aware of the natural resources obligations within SHOBA, and at least 1 day a week is usually allowed for natural resources programs to conduct their activities. Weeks with reduced natural resource access, including infrequent events that exclude natural resources personnel from SHOBA for 10 to 20 days, are announced in advance and provide natural resources managers the opportunity to plan accordingly. Impact Areas I and II have been indefinitely closed ‘‘for any purpose, including monitoring and management of endangered and sensitive species and their habitat’’ for safety reasons (US Navy 2008a, p. 2–45). Access to additional areas on the island where unexploded ordnance has been found is often restricted for

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natural resources personnel, but these areas are removed once they are assessed by unexploded ordnance specialists and are deemed safe for entry (Figure 9). When closed, these restricted access areas (RAAs) can be accessed if accompanied by a trained unexploded ordnance technician (Munson 2019, pers. comm.). Due to these various military training activities, land use has been considered a threat to Castilleja grisea. Training and other land use activities have multiple potential impacts to C. grisea, including disturbances to soil and vegetation, spread of nonnative plant species, creation of road ruts and trails, and compaction of soils (USFWS 2008b, pp. 96-99). Potential training impacts vary by area (Table 3). However, fewer than 5% of the individuals considered current occur within one of these training areas (Figure 9, Table 4). All of the locations and individuals in the TAR and Impact Areas are located in two watersheds (watershed IDs WS_1145 and WS_1158). However, C. grisea locations within the IOA are spread throughout 16 watersheds (Table 4), and most locations are near the perimeter of the IOA, where they are at the least risk of foot traffic associated with training.

Table 4. The numbers of locations and total individuals that occur within each of the training area types based on the distribution of Castilleja grisea considered current. % of Locations Individuals Watersheds* population TAR 1 3 1 0.01% AVMA 0 0 0 0.00% IOA 31 863 16 1.79% Impact Areas 42 1,223 2 2.54% *Individual watersheds overlap multiple training areas (TAR watershed is also one of the Impact Area watersheds, etc.)

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Figure 9. Locations of Castilleja grisea (CAGR) as considered current in relation to the training areas on SCI, including the Impact Areas, the Training Areas and Ranges (TARs), the Assault Vehicle Maneuver Areas (AVMAs), the Infantry Operations Area (IOA), and the Shore Bombardment Area (SHOBA), which occupies the southern third of the island. Current Restricted Access Areas (RAAs) are also shown, but these change as unexploded ordnance are removed.

Military training activities within training areas (primarily the IOA, TARs, and AVMAs) can entail the movement of vehicles and troops over the landscape and thus include the potential of trampling or crushing individuals or groups of plants. Based on the distribution of Castilleja grisea and types of troop movements likely to occur, impacts due to trampling and crushing are most likely to occur along roads (within 100 ft) or the AVMR (within 50 ft) and in the Impact Areas. However, any effects of foot traffic on a local occurrence of this species would be dispersed (because the Marines are spread out), minor (trampled leaves or broken branches),

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infrequent (up to twice per year, generally less), and temporary (USFWS 2008b, p. 91-102; Vanderplank et al. 2019, p. 12). Further, few documented locations of C. grisea occur within these areas (Table 4). No C. grisea are located within 50 ft of the AVMR. The AVMAs, IOA, and several TARs are located along the central plateau or spine of the island, where few plants have been documented to date (see Figure 6). The distribution of C. grisea is primarily across the southern 15.5 mi (25 km) of the island, particularly along the eastern escarpment. Steep slopes along the eastern escarpment likely afford C. grisea some topographic protection from current and future vehicle and troop movements. The southern portion of Castilleja grisea’s distribution extends through SHOBA (USFWS 2012, p. 29116). Most of SHOBA serves as a buffer zone around the Impact Areas, and there is no discernible change in the vegetation looking across the fence inside and outside of SHOBA (McFarland 2019, pers. obs.; Uyeda 2019, p. 22). Certain munitions exercises within the Impact Areas within SHOBA involve the use of incendiary devices, such as illumination rounds, white phosphorous, and tracer rounds, which pose a high risk of fire ignition and a direct threat to habitat due to associated ground disturbance and land demolition (USFWS 2008b, p. 11–13). Because of the elevated risk of fire associated with training activities, live and inert munitions fire are targeted towards Impact Areas I and II within SHOBA where bombardments and land demolition are concentrated. Currently, the Impact Areas are closed to nonmilitary personnel, so the current status of C. grisea there is largely unknown (USFWS 2008b, p. 50). However, the Impact Areas support native vegetation, as seen from the roads, via unmanned aerial systems, and through other aerial imagery. Observations have been made of C. grisea persisting in TAR 21, which is accessible at the southern end of Impact Area I (Munson 2019, pers. comm.), and increases in C. grisea in the Impact Areas despite the long history of use for training there have been reported (US Navy 2008a, p. D-19). Although the designation of RAAs could make it more difficult to schedule surveys needed to assess potential training-related habitat impacts in some watersheds in the future (Figure 9), surveys are not precluded within the RAAs, and other federally listed species, including the San Clemente bush mallow (Malacothamnus clementinus) and the San Clemente loggerhead shrike (Lanius ludovicianus mearnsi), are monitored regularly within them.

Management efforts The Navy has demonstrated its efforts to help conserve and manage listed species on the island through amelioration of habitat impacts by military activities through implementation of the 2008 BO (USFWS 2008) and Integrated Natural Resources Management Plan (INRMP) (US Navy 2013a), including invasive species control island-wide, including near listed species, biosecurity protocols, public outreach to promote compliance, restoration of sites that support sensitive plants, habitat enhancement for sensitive and listed species, fuelbreak installation to minimize fire spread, and fire suppression inside and outside of SHOBA to protect threatened, endangered, and other priority species (US Navy 2013a, p. 3.45; Vanderplank et al. 2019, pp. 15, 18-19; Munson 2019, pers. comm.). Changes to training have and will be subject to environmental review under applicable laws and regulations, including NEPA and ESA, and impacts to federally listed and sensitive species will be addressed (O’Connor 2019, pers. comm.).

Summary About 35% of SCI is located within a training area (Table 3), and only 5% of the current population of Castilleja grisea occurs in these areas (Table 4). Since not all of the land within

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each training area is used for training, land use likely threatens less than 5% of the distribution of C. grisea (Table 4). While dispersed foot traffic is possible throughout the entirety of the IOA, we expect this buffer around the AVMR to be where any major impacts may exist. We will discuss this impact further in Section 4.2, concerning roads. Military activities on San Clemente Island have been and will continue to be dynamic as they evolve to meet new requirements. The Navy has begun evaluating the need for changes to the actions analyzed in the 2008 EIS and associated BO. Any changes are expected to be incremental, as they have been in the past. Such changes are subject to environmental review under applicable laws and regulations, including NEPA and ESA, and impacts to federally listed and sensitive species will be addressed. There is also ongoing management of related threats (including wildland fire, soil erosion, invasive species) pursuant to the San Clemente Island Integrated Natural Resources Management Plan.

4.2 Erosion and Roads Erosion and associated soil loss caused by degradation of the vegetation due to the browsing of feral goats and rooting of feral pigs modified the island’s habitat significantly and resulted in increased erosion over much of the island, especially on steep slopes where denuded soils could be quickly washed away during storm events (Johnson 1980, p. 107; Tierra Data Inc. 2007, pp. 6–7; US Navy 2013a, pp. 3.32–3.33). Since the feral animals were removed, much of the vegetation has recovered, and natural erosion on the island has decreased significantly (US Navy 2013a, p. 3-33, Vanderplank et al. 2019, p. 15). Erosion problems currently are limited to localized areas, and because of topography and soil characteristics, there always will be the potential for localized erosion to occur at sites across the island. Periods of heavy rainfall can cause localized erosion, but these areas are difficult to predict. Accelerated soil erosion from anthropogenic causes tends to occur at the heads of canyons, ephemeral drainages, and in areas where groundwater drainage causes “piping,” the formation of underground water channels, which occur on clay soils. Military training activities could lead to erosion that could impact Castilleja grisea, but few individuals occur in these designated training areas (Table 4) (Tierra Data Inc. 2007, pp. 1– 45). If erosion were to occur or be initiated in a single watershed, the effects would be confined to that watershed. However, C. grisea is found mostly on non-clay soils that are not prone to piping, and no piping or soil erosion channels have been observed in C. grisea locations (Vanderplank et al. 2019, p. 16). Only 2% of individuals detected in the 2011 and 2012 surveys were located in areas mapped as clay soils (Figure 4) (Vanderplank et al. 2019, p. 16). Erosion was the primary concern associated with use of the Assault Vehicle Maneuver Corridor (AVMC), which connects the AVMAs. Piping has been documented within the AVMAs (Vanderplank et al. 2019, p. 16). However, the Navy has delineated unpaved roads that will channel vehicle traffic through some portions of the AVMA, confining vehicles to these roadways, which reduces loss of vegetation cover and allows for better control of erosion (Vanderplank et al. 2019, p. 16). As noted in Section 4.1, no known Castilleja grisea occur in the AVMAs or AVMC. Of the adjacent watersheds that could be impacted by the AVMAs, only 3 are occupied, supporting 44 individuals. Implementation of the Erosion Control Plan (US Navy 2013b, entire) is expected to prevent erosion from adversely affecting C. grisea, but even if the plan were to fail to meet its objectives, few individuals would be affected by erosion. Though the operational tempo analyzed in the 2008 EIS and BO has not been achieved to date, even

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when it is, development of and adherence to the Erosion Control Plan will continue to reduce species impacts in the AVMC below the already low levels projected in the EIS. Roads can concentrate water flow, causing incised channels and erosion of slopes (Forman and Alexander 1998, pp. 216–217). Along the eastern escarpment, Castilleja grisea is found in steep canyons in proximity to Ridge Road, the primary road that traverses most of the island from northwest to southeast. Roadside occurrences of C. grisea may experience runoff during storm events (US Navy 2008a, pp. G.4, G.8). Increased erosion near roads could potentially degrade habitat, especially along the steep canyons and ridges. On occasion after particularly heavy rainfall events, localized areas of high erosion stemming from roadways have been noted; however, regular road maintenance and repair of associated damage minimizes the potential for such problems to spread, and erosion impacts to C. grisea from such events have never been observed and are unlikely. In the downlisting rule, it was proposed that C. grisea that occur within 500 ft (152 m) of a paved or unpaved road could be subject to road effects that degrade the habitat quality (Forman and Alexander 1998, p. 217; USFWS 2013 p. 45427). However, based on expert opinion and observations on San Clemente Island since the 2013 rule, the likelihood of impacts to C. grisea from runoff or other erosional processes stemming from roads is very low, and increased erosion associated with roads is not evident as far from the road network as analyzed in the proposed rule (O’Connor 2019, pers. comm.). The conditions of roads on San Clemente Island are evaluated and maintained, which minimizes the potential for habitat impacts adjacent to them, particularly as the distance from the roads increases. Erosion stemming from a roadway would have a high chance of being noticed early and managed accordingly. Still, as a precaution, the SSA team, consisting of both USFWS and US Navy employees, decided that a 100 ft (30 m) buffer around roads is a more appropriate distance over which negative impacts to habitat could be perceptible and should be evaluated. Likewise, the likelihood of crushing individual plants during military training involving foot traffic in maneuvers along roads tends to be more concentrated close to roads and decreases farther away (see Section 4.1) (O’Connor 2019, pers. comm). Additionally, other indirect effects associated with roads, such as the introduction and spread invasive plants (see Section 4.3), are most likely alongside roads. It is important to note that much of the invasive species control on San Clemente Island is focused along roads for this reason, and new occurrences of invasive species generally are more likely to be noticed and eradicated if they occur adjacent to roads. The expert team applied the same distance (100 ft [30 m]) when considering these other potential mechanisms of habitat degradation associated with roads. Of the distribution considered current, 144 individuals in 6 watersheds are located within 30 m (100 ft) of a road or the AVMR (Table 13 in Appendix A). Island-wide, this represents 7% of the total occupied watersheds and 0.2% of the total individuals. Within two occupied watersheds that could be affected by road impacts (including trampling, erosion, and increased invasive species), 100% of Castilleja grisea individuals are located near a road. Within two other watersheds, 50% of the individuals are at risk of road impacts (see Table 13 in Appendix A).

Management efforts The Navy monitors and evaluates soil erosion on SCI and uses multi-year data to assess priorities for remediation (SERG 2006, entire; SERG 2015a, entire). Efforts are made to restore areas where erosion occurs, through revegetation efforts and the installation of erosion control materials (SERG 2016, p. 2). The Navy incorporates erosion control measures into all site feasibility studies and project design to minimize the potential to exacerbate existing erosion and avoid impacts to listed species The INRMP requires that all projects include erosion control

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work (US Navy 2013a, p. 3–33). These conservation actions include best management practices, choosing sites that are capable of sustaining disturbance with minimum soil erosion, and stabilizing disturbed sites (US Navy 2013a, pp. 3.33–3.37). Originally, the AVMAs were to allow for the most extensive off-road movement of tracked vehicles, and the area within them was anticipated to experience increased soil erosion due to reductions in vegetation cover (Vanderplank et al. 2019, p. 16). To address soil erosion within the AVMC, the US Navy included a conservation measure in the 2008 EIS to develop an erosion control plan for portions of the AVMC, including the AVMAs, Artillery Firing Points (AFPs), Artillery Maneuver Points (AMPs), and IOA, that would accomplish the following: (1) minimize soil erosion within these training areas and minimize offsite impacts; (2) prevent soil erosion from adversely affecting federally listed or proposed species or their habitats; and (3) prevent soil erosion from significantly impacting other sensitive resources, including sensitive plant and wildlife species and their habitats, jurisdictional wetlands and non-wetland waters, the Area of Special Biological Significance surrounding the island, and cultural resources. The plan includes specific guidelines for the development and application of best management practices (BMPs) to minimize impacts to sensitive resources, including Castilleja grisea and its habitat, site-specific erosion control recommendations, restrictions of vehicle maneuvering when soils are wet, operator education, vegetation management measures, methods to prevent gully development and restore existing gullies, and an adaptive management and monitoring plan to assess the effectiveness of and modify BMPs as needed (US Navy 2013b, p. 37-50, 111; Vanderplank et al. 2019, p. 16). The plan is prescriptive; measures have been or will be implemented prior to use of areas to which they apply. Following issuance of the BO and signature of the ROD, funding was secured, the Erosion Control Plan was developed, and the final plan received concurrence from the US Fish and Wildlife Service (O’Connor 2019, pers. comm.). Subsequent to finalization of the Erosion Control Plan in 2013, development of the AVMAs has involved working with military operators to determine more precisely how areas would be used based on findings and recommendations in the plan, and implementation has taken a phased approach. This effort has resulted in the delineation of unpaved roads to channel vehicle traffic through some portions of the AVMAs, which will substantially reduce the level of ground disturbance from those anticipated in the EIS. Design of these roads will be the focus of future planning efforts. Areas in which roads are being developed have not been used and a battalion sized landing has not been conducted yet, but platoon sized landings involving 14 AAVs have been conducted approximately quarterly in other portions of the AVMAs and the IOA (O’Connor 2019, pers. comm.).

Summary Despite existing levels of soil erosion on the island, the distribution of Castilleja grisea has increased since listing. Current erosion issues are localized, and erosion is generally decreasing on the island as the vegetation continues to recover. The Navy incorporates erosion control measures into all projects to minimize the potential to exacerbate existing erosion and avoid impacts to habitat and listed species. Although the erosional processes and potential related threats to C. grisea must be considered at an island-wide scale, because erosion impacts are localized and managed, the loss of individuals due to erosion is unlikely. Implementation of the Erosion Control Plan (US Navy 2013b, entire) is expected to prevent or correct erosion that may occur as a result of military operations and training in the AVMA and IOA. As proposed, implementation of the plan should prevent erosion from

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adversely affecting Castilleja grisea, but even if the plan were to fail to meet its objectives, few current locations of individuals would be affected by erosion. However, by incorporating recommendations from the erosion control plan and working with military operators to determine more precisely how areas would be used, the Navy has delineated unpaved roads that now channel vehicle traffic through some portions of the AVMA. Therefore, vehicles are confined to these roadways, which reduces loss of vegetation cover and allows for better control of erosion (Vanderplank et al. 2019, p. 16).

4.3 Invasive plants Contemporaneous with and likely aided by feral grazing animals, a large number of invasive non-native plant species have become naturalized on SCI. At listing, the spread of nonnative plants was identified as a threat to the recovery of Castilleja grisea (USFWS 1977, p. 40682, 40684), and nonnative plants are considered an island-wide threat to the native vegetation (USFWS 2012, p. 29117). Nonnative plants can alter habitat structure and ecological processes such as fire regimes, nutrient cycling, hydrology, and energy budgets, and they can compete with native plants for water, space, light, and nutrients (USFWS 2012, p. 29117). Non-native annual grasses noted at the end of the grazing period are now widespread on SCI with the most-common being Avena barbata (slender wild oat), Bromus madritensis ssp. rubens (red brome), B. hordeaceus (soft brome), B. diandrus (ripgut brome) and Hordeum murinum (false barley) (Keeley and Brennan 2015, p. 4). The invasion of nonnative annual grasses on the island may have caused the greatest structural changes to Castilleja grisea habitat, especially on the coastal terraces and in swales (USFWS 2007, p. 4-5). Annual grasses vary in abundance with rainfall, potentially changing the vegetation types from shrublands to grasslands and increasing the fuel load in wet years (Battlori et al. 2013, p. 1119). Although most of the invasive species likely were brought to the island while it was being ranched, invasions by previously undocumented non-native grasses continued to be found on SCI; e.g., the discovery of Schismus sp. (Mediterranean grass) and the fire-tolerant weeds Brachypodium distachyon (purple false brome) (USFWS 2007, p. 5), Ehrharta calycina, and E. longiflora (African veldt grasses) (US Navy 2013a, p. 3-90). A brief review of the occurrence data collected in 1996 and 1997 reveals that Castilleja grisea was associated with non-native annual grasses in 24 of its 77 locations (31 percent) (Junak and Wilken 1998, field data). Castilleja grisea is often associated with vegetation types where nonnative grasses are present but not a dominant component of the plant community (Tierra Data Inc. 2005, pp. 29–42). Surveys conducted in 2011 and 2012 found just 4 occurrences (170 individuals) of C. grisea in communities dominated by invasive grasses (Vanderplank et al. 2019, p. 12). Populations of Castilleja grisea within 500 ft (152 m) of roads may be subject to effects that degrade the habitat quality along the road (Forman and Alexander 1998, p. 217). This disturbance along roadsides tends to create conditions (high disturbance, seed dispersal from vehicles, ample light and water) preferred by nonnative species (Forman and Alexander 1998, p. 210). Nonnatives, including Foeniculum vulgare (fennel) and Mesembryanthemum crystallinum (crystalline iceplant), have been found in the disturbed shoulders along China Point Road in SHOBA (Braswell 2011, pers. obs. in USFWS 2012), but these nonnatives have not been considered a threat to locations of C. grisea. Potential impacts of nonnative plants on Castilleja grisea include precluding germination (i.e., competitive exclusion), preventing pollination (e.g., C. grisea plants are not obvious to

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pollinators due to tall stands of non-native grasses), and carrying fire in areas that would not otherwise burn. While there may be these or other unquantified indirect effects to the fitness of C. grisea due to the invasive species already present on the island, they do not seem to be impeding the population growth of C. grisea. Further, since the removal of feral grazers and browsers, the vegetation has been recovering and is no longer comprised of the early seral communities, the first to colonize disturbed areas (Stratton 2005, p. 216). The island has more intact habitats, reduced erosion, and a stronger suite of native competitor species, making the conditions less favorable to invasion. Some habitats that underwent considerable invasion historically, such as the central grasslands, are still heavily dominated by non-native species, but rocky soils, which support C. grisea, are less susceptible to invasion by annual grasses (Allan 1999 in Vanderplank et al. 2019).

Management efforts The Navy has monitored and controlled the expansion of highly invasive non-native plant species on an ongoing basis since the 1990s (O’Connor 2019, pers. comm.), and primary target species have included Brassica tounefortii (Saharan mustard), B. nigra (black mustard), Foeniculum vulgare (fennel), Asphodelus fistulosus (aspohodel), Stipa milaceae (smileo grass), Ehrharta calycina (African veldt grass), Plantago coronopus (buckhorn plantain), Tragopogon porrifolius (salsify), and Caprobrotus edulis (iceplant); additional priority species may also be controlled as they are located (e.g., SERG 2016, p. 45-46). In general, the Navy treats over 100,000 individuals of these various species annually. Control of these invasive plants benefits the ecosystem on SCI by reducing their distribution and minimizing the potential that they will invade habitat occupied by listed and at-risk taxa. Because invasive species introductions are more likely to occur along roadsides and because roads function as corridors for the spread of invasive species propagules, much of the invasive species treatment on the island focuses on roadsides; however, other areas highly susceptible to invasive species introductions (such as graded areas, soil stockpiles, and mowed areas) also are focal areas for control. High-priority invasive plants are treated at locations across the island. This control strategy has minimized the need to treat invasive plant species within areas occupied by federally listed plants. While many conservation measures to limit the introduction and spread of nonnative plants are included in the INRMP (US Navy 2013a, pp. 3.289–3.290) and required in the 2008 BO (USFWS 2008, pp. 58–66) (Table 14 in Appendix B), the recently-completed Naval Auxiliary Landing Field San Clemente Island Biosecurity Plan (US Navy 2016, entire) will help more effectively control the arrival of potentially invasive propagules than similar plans on non- military islands. The plan works to prevent and respond to new introductions of non-native species and bio-invasion vectors. Through implementation of this plan and the ongoing island- wide nonnative plant control program, potential impacts from nonnative plants are expected to be minimized (O’Connor 2019, pers. comm.; Munson 2019, pers. comm.).

Summary Non-native species are extensively distributed across SCI both as a result of post-grazing colonization of weedy species in highly-disturbed habitat and accidental introduction of new weeds which may inevitably occur either naturally or inadvertently through human activities. However, all vegetation communities have been recovering on SCI since the final removal of feral grazers, and naturalized grasslands (the most fire-prone of non-native vegetation communities) constitute a small proportion of the island at this time. Non-native annual and perennial grasses, however, are widespread on the island and have been for many decades. No

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assessment to track weediness within occupied habitat areas has been done, but given that Castilleja grisea is a generalist hemiparasite with respect to host plants, no need for such a study is indicated at this time. Although C. grisea is not found within naturalized, non-native grasslands (Figure 3), there is the potential that exotic annual grasses, which are widespread on the island, could affect fire-regimes. However, it does not appear as if these grasses are expanding, and they have been present during the recorded fire history. This potential is further addressed in Section 4.4. The Navy makes significant efforts to control highly invasive non-native perennial grasses and non-native forbs to preclude their expansion into habitat areas and areas in which weed control would be difficult due to terrain and access challenges. Because Castilleja grisea is a generalist hemiparasite, its distribution is not likely to be significantly limited by co-occurring vegetation. We have no information on the relative presence of weedy plants within habitat occupied by C. grisea, but as noted, the role of invasive grasses on fire-regime might be more of a potential threat to recovery than simple presence of non-native plants within habitat areas. Because data on the abundance and density of invasive plants and monitoring of change over time are lacking, we have no way to quantitatively assess the effect of non-native, invasive species on C. grisea individual fitness; however, C. grisea’s range has expanded despite the presence of nonnative plants on SCI.

4.4 Fire The history of fire on the island prior to 1979 is largely unknown, but while the island was used for ranching, fires were set intermittently to increase the cover of forbs and grasses (US Navy 2009, p. 3-2; US Navy 2013a, p. 3.47). After the island was purchased by the U. S. Department of the Navy in 1934, however, fire became a more common occurrence throughout much of the island. Fire history for most of the island has been documented since 1979. Since that time, over 50 percent of the island has experienced at least one wildfire with smaller areas on the island having burned up to ten times between 1979 and 2018 (US Navy 2013a, p. 3-47; US Navy, unpublished data). The number and extent of fires (acres burned) varies annually as does fire-severity (Figure 10). Most large fires are ignited in the Impact Areas, and thus, the majority of acreage that has burned has been concentrated in SHOBA (US Navy 2013a, p. 3-45). Most of these fires are classified as a severity of 4 or 5, considered lightly burned or scorched, which have little effect on shrubs (Table 5) (US Navy 2009, p. 4-52). For fires with associated severity data (2007 to present), 15.6% of the area burned has been of a severity class that has detrimental effects on shrubs, class 1 through 3, considered completely-burned to moderately-severe (Figure 13). The largest area that burned at these severities burned in 2017 (Figure 10). Typically, due to the patchy nature of fires, not all areas within a fire footprint are burned uniformly; therefore, not all plants in a burn polygon are necessarily burned or burned at the same severity (SERG 2012, p. 39). Although fire was not considered a threat to Castilleja grisea habitat at the time of listing (USFWS 1977, p. 40682), frequent or severe fires could threaten the viability of C. grisea (USFWS 2012, p. 29121). The response of C. grisea to fire may also be governed by the response of its host species to fire (USFWS 2012, p. 29121). High fire frequency may be a potential threat that could limit the distribution of Castilleja grisea by overwhelming its tolerance threshold (Brooks et al. 2004, p. 683; Jacobson et al. 2004, p. 1). At higher than natural fire frequencies, fire has the potential to exceed a plant’s capacity to

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persist by depleting seed banks and reducing reproductive output (Zedler et al. 1983, pp. 811– 815). A fire return-interval of three years or fewer has been shown to negatively impact woody shrubs on SCI (Keeley and Brennan 2015, p. 3). The historical fire return interval on SCI is unknown but a majority of the areas that have experienced more than one fire in the last 20 years (1999–2018) are located on the central plateau in SHOBA (Figure 12). Very few areas where Castilleja grisea occur have burned more than once in the last 20 years. Island-wide during this time, fires have burned a portion of 88 watersheds. Of the distribution considered current, 133 of 601 locations totaling 8,596 individuals in 29 occupied watersheds are located in an area that had a fire in the last 20 years (Figure 12). Nineteen occupied watersheds had 50% or more of their area burn in the last 20 years, and 8 watersheds had 50% or more of their area burn twice or more in the last 20 years (see Table 13 in Appendix A). Forty-seven locations, totaling 4,195 individuals, are located in an area that had two or more fires in the last 20 years. No C. grisea burned more than 3 times in the last 20 years. Thus, fire return intervals have not exceeded the postulated ecological tolerance of C. grisea in areas where the species occurs. While increased fire frequency could lead to localized changes in vegetation on SCI, fires are currently relatively infrequent across the majority of the island, even given the intensified military uses over the last decade (Figure 12).

Table 5. Fire severity classes and definitions, reproduced from the US Navy 2009 Fire Management Plan for SCI, with severity classes adapted from the National Park Service (1992). Effects on Effects on Effects on Fire severity class litter/duff herbs/grasses shrubs Effects on trees 1 Completely Burned Burned to ash Burned to ash Burned to ash, Burned to ash or few resprouts killed by fire 2 Heavily Burned Burned to ash Burned to ash Burned to ash, Killed by fire or some resprouts severely stressed 3 Moderately Burned Burned to ash Burned to ash Burned to Crown damage singed, some only to smaller resprouts trees 4 Lightly Burned Blackened, but Burned to ash, Singed/stressed, No effect on mature not evenly some resprouting many trees, may kill converted to ash resprout/recover seedlings/saplings 5 Scorched Blackened Singed/stressed, Not affected, No effect on trees many slight stress resprout/recover 6 Unburned* – – – – *Unburned inclusions within a fire should be classified as 6.

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Figure 10. Total acres on SCI that have burned annually in wildfires and acres that were recorded to have burned at a moderate to high severity (severity classes 1, 2, or 3).

While fires are occasionally ignited by activities north of SHOBA (US Navy 2013, p. 3- 45-3–47; USFWS 2018, GIS data), the risk of frequent fire is higher in Impact Areas I and II and within SHOBA (USFWS 2008, p. 50). The distribution of Castilleja grisea within SHOBA is mostly along the eastern escarpment, away from the Impact Areas and downslope, reducing the potential for frequent fire. However, in 2017, a large fire burned part of the eastern escarpment within SHOBA, where no other recorded fire has burned. After having seemingly gone out, the fire restarted the next day and response was therefore delayed, which has prompted a change to monitoring fire that are thought to be out (O’Connor 2019, pers. comm.). The fire burned 1,522 acres, almost all (98%) of which was of moderate to high severity (3, 2, or 1 severity class). The outline of this 2017 high severity fire encompasses 7,595 individuals of C. grisea in 22 watersheds of the distribution considered current (Figure 13); vegetation plot monitoring in 2019 has indicated that many plants have persisted or have resprouted here (SERG 2019, unpublished data). The precise impact to C. grisea following the 2017 higher severity fire on the eastern escarpment is difficult to interpret. Surveyors traversed the burn and attempted to relocate 50 previously known locations totaling 3,971 individuals that burned at severity 2 or 3 in 2017. Because locations are an approximate point representation of the center of a group of plants, we were unable to match up specific locations. However, surveyors located 843 individuals of C. grisea at 45 locations within this same search area. It is unknown how many of the other locations were missed, as the terrain and vegetation limits visibility and can impede detection. Tracks show that surveyors were within 10 m of original documented locations, but given the intrinsic GPS error and the nature of a location definition, they may have been further away in some cases. The majority of the plants were noted to be large plants that would have been present during the burn; surveyors estimated <5% were new recruits, but specific data on plant age were not collected. Surveyors also located an additional 858 individuals at 30 locations outside the burn polygons that were previously unknown. These data indicate that many individuals that burned, up to 80%, were lost in the fire. However, the data also indicate that some, although seemingly few, new recruits have become established after the fire burned. Sprouting from seed is thought to be a common response to fire in other species of Castilleja as

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noted in Section 2.6, but germination following this fire is seemingly low. The data also indicate that there are many individuals on the landscape in 2019 that have not experienced fire that were previously unknown, indicating that the current population is likely larger than currently estimated. Individuals of Castilleja grisea have been noted to recover following fires of lower severity. The Ranch Fire and Ridge Extension fires in 2012 were considered severity class 4; new, vegetative growth on previously-burned C. grisea was observed in 2013 on some, but not all, adult plants; the surviving percentage is unknown (SERG 2013, p. 49; SERG 2015c, p. 40). Monitoring of the Ranch Fire and Ridge Extension Fires were completed in 2016 and noted extensive regrowth of the native vegetation and no erosion resulting from the loss of vegetation (SERG 2016, p. 43). While non-native annual grasses also rebounded, no new infestations of high-priority invasive plants were recorded (SERG 2016, p. 43). Castilleja grisea has been observed reoccupying burned sites in similar numbers of individuals after adult plants were killed by fire (US Navy 2002, p. D-10; USFWS 2012, p. 29093), keeping with post-fire responses of other species of Castilleja (as noted in Section 2.5). The Navy has significantly expanded the number of locations where live fire and demolition training can take place (USFWS 2008, pp. 21– 37). In addition to demolitions, certain proposed munitions exercises involve the use of incendiary devices, such as illumination rounds, white phosphorous, and tracer rounds, which pose a high risk of fire ignition. However, the number of acres that burn annually varies greatly, and the biggest fire years in the last 15 years (2012 and 2017) have burned less than half the acreage of the biggest fire years between the time of listing and now (Figure 11). Fires topping 8,000 acres burned in 1985 and 1994, before fuel breaks were routinely installed and prior to implementation of the 2009 San Clemente Island Wildland Fire Management Plan (O’Connor 2019, pers. comm.).

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Figure 11. Acres burned annually on SCI for years where fires were estimated since listing. Fire management was initiated around 1999.

Although fire ignition points are concentrated in the military training areas, fires that escape these areas could potentially spread to other areas of the island, but due to vegetation and topography, these fires have usually been confined to the same small areas (Munson 2019, pers. comm.). However, fires that escape from training areas are not likely to affect the entire distribution of Castilleja grisea at one time because this taxon has sufficient redundancy given its wide distribution in many watersheds where it is associated with steep canyon areas where fires are less likely to impact individuals (USFWS 2012, p. 29121). One difficulty in assessing the interaction between fire and distribution of Castilleja grisea is that little survey data exists in the burn polygons in the years prior to and immediately following fires. Apart from the more-recent fire data (i.e., 2012–2017), we do not know whether C. grisea occurred in a burned area at the time of the fire. While much of the range of C. grisea has burned since 1979, much of the survey effort has occurred after 1996. Using the historical datasets, we found a total of 366 of 601 locations were in an area that had a documented fire since 1979. However, the vast majority of these locations (276) either were in places where the last fire had burned more than 10 years before the survey was recorded or the fire had happened after the point was recorded. We did find 2,236 individuals located in an area that had a fire ten years or fewer prior to the count (Table 12 in Appendix A). Whether the rarity of locations in recently burned areas is because C. grisea is unlikely to survive a fire, will only reestablish itself from the seed bank in an area after a certain number of years post fire, or are a product of the survey efforts is still unknown. The lower abundance of plants in fire-prone regions could be due to fire (fire precludes the establishment of plants or affects their survival), or C. grisea may just naturally occur less frequently in habitats where fires are prone to occur (the western slope and the central plateau).

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Figure 12. Locations of Castilleja grisea (CAGR) points considered current in relation to areas where fires have burned in the last 20 years (1999-2018, after the initiation of fire management), including number of fires in that time.

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Figure 13. Locations of Castilleja grisea (CAGR) points considered current in relation to areas where fires where severity data is known have burned (2007-2018). Severity categories 1, 2, and 3 have the potential to burn shrubs where they will not resprout; severity categories 4 and 5 have little to no effect on shrubs.

Management efforts The San Clemente Island Wildland Fire Management Plan (FMP) stipulates monitoring of live fuel-moisture and establishes a threshold below which training requirements are altered to reduce ignition risk (US Navy 2009, pp. 4.15–4.16). These live fuel moisture levels, combined with wind speed, define a fire danger rating which at various levels indicate specific munitions that are allowable and precautions that must be in place (standby firefighting engine, crew, and

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other resources, helicopter on fire alert, etc.) (US Navy 2009, p. 4.19). The FMP stipulates that Castilleja grisea is a management focus plant, such that individuals are given special consideration and protection from fires (US Navy 2009, p. 4.10). The Navy’s fire management program maintains ground and aerial suppression assets to fight fires in all areas outside of Restricted Access Areas and Impact Areas (US Navy 2013a, p. 3.45) (see Figure 9). While most fires burn themselves out in a short amount of time, fires are monitored closely after ignition (Munson 2019, pers. comm.). If a threat is perceived to lives, structures, or sensitive species, the fire is fought unless there is a threat of unexploded ordnance or another a safety risk, such as high winds. Since the 2017 fire on the eastern escarpment, monitoring for complete extinguishment has increased, and increased monitoring requirements will be included in all future versions of the FMP (Munson 2019, pers. comm.). The US Navy has constructed fuelbreaks around the Impact Areas to manage the spread of fire out of the Impact Areas (USFWS 2012, p. 29118). However, these fuelbreaks rarely have helped contain a fire as fires have infrequently approached them, and those that did were only sometimes contained by the fuelbreak. Thus, fuelbreak locations and installation methods have changed over time, and for the 2019 fire season, fuelbreaks were installed only along the existing roadways (Munson 2019, pers. comm.). As roads already serve as good fuelbreaks, increasing the width of this vegetation gap through application of a fire retardant along the existing roadways creates a more effective fire management tool. These fuelbreaks were designed with the protection of the sensitive species and resources on the eastern escarpment, which is protected by Ridge Road, in mind (Munson 2019, pers. comm.). Maintenance of these fuelbreaks reduces the likelihood and frequency of fires spreading to sensitive areas and habitats, such as those occupied by Castilleja grisea. Fuelbreaks on SCI are created using herbicides and strip burning and are maintained using herbicides and fire retardant (Phos-Chek D75F) (USFWS 2008, pp. 97–98). The Navy avoids application of Phos-Chek within 300 ft (91.4 m) of mapped listed species locations to the extent that has been allowable with previous fuelbreak installation (USFWS 2008, pp. 97–98). The Navy conducts preseason briefings for firefighting personnel on the guidelines for fire suppression and limitations associated with the use of Phos-Chek (USFWS 2008, pp. 97–98). To minimize the potential for effects to listed species, the Navy considers the documented locations of listed species on the island as fuelbreak lines are developed (USFWS 2012, p. 29119). The Navy also conducts annual reviews of fire management and fire occurrences that allow for adaptive management and aim to minimize the frequency and spread of fires that could result in loss of individuals of Castilleja grisea (USFWS 2012, p. 29121).

Summary Fire poses a threat to individuals of Castilleja grisea, as fires have the potential to burn most places on the island, but land use, vegetation, and historical patterns indicate that fires are most likely to burn in the same areas they have historically. Fires have been generally localized, infrequent, and of low severity, and most have burned in regions were C. grisea is not documented. While the 2017 fire was in an unprecedented location and of an unprecedented size and severity, efforts are in place to keep this type of incident from happening again. While severe fires can kill plants, C. grisea may benefit from periodic or low-intensity fires, and individuals have been noted to survive even more severe fires. Under current fire patterns, C. grisea has increased in distribution and population size; the population has especially become numerous along the eastern escarpment, where few fires ever burn; however, if fire becomes more common or more severe in the future, C. grisea numbers could be greatly reduced in areas that burn.

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Although the Navy continues to work to minimize any adverse impacts of fire on C. grisea through adaptive management and implementation of its Wildland Fire Management Plan, the Navy has managed fire sufficiently to allow the species to increase significantly in distribution and abundance.

4.5 Climate Change Since the listing of Castilleja grisea (USFWS 1977, p. 40684), the potential impacts of ongoing, accelerated climate change have become a recognized threat to the flora and fauna of the United States (IPCC 2007, pp. 1–52; PRBO 2011, pp. 1–68). Climate change is likely to result in warmer and drier conditions, with high overall declines in mean seasonal precipitation but with high variability from year to year (IPCC 2007, pp. 1–18; Cayan et al. 2012, p. ii; Kalansky et al. 2018, p. 10). SCI is located in a Mediterranean climatic regime with a significant maritime influence. Current models suggest that southern California will likely be adversely affected by global climate change through prolonged seasonal droughts and rainfall coming at unusual periods and different amounts (Pierce 2004, pp. 1–33, Cayan et al. 2005, pp. 3–7, CEPA 2006, p. 33; Jennings et al. 2018, p. iii). Climate change models indicate a 4 to 9 degrees Fahrenheit (2 to 4 degrees Celsius) increase in average temperature for the San Diego Area of southern California by the end of the century (Jennings et al. 2018, p. 9), with inland changes higher than the coast (Cayan et al. 2012, p. 7). By 2070, a 10 to 37 percent decrease in annual precipitation is predicted (PRBO 2011, p. 40; Jennings et al. 2018, p. iii; Kalansky et al. 2018, p. 10), though other models predict little to no change in annual precipitation (Field et al. 1999, pp. 8–9; Cayan et al. 2008, p. S26). SCI typically receives less rainfall than neighboring mainland areas (Tierra Data Inc. 2005, p. 4). However, predictions of short and long-term climatic conditions for the Channel Islands remain uncertain. It is unknown at this time if climate change in California will result in a warmer trend with localized drying, higher precipitation events, and/or more frequent El Niño or La Niña events (Pierce 2004, p. 31). Low-level temperature inversions are common along the California coast and Channel Islands, and these inversions form low cloud cover (fog), otherwise known as the marine layer, which has a strong influence on coastal ecosystems and SCI (US Navy 2013a, pp. 3.13, 3.26). Although the island has a short rainy season, the presence of fog during the summer months helps to reduce drought stress for many plant species through shading and fog drip, and many species are restricted to this fog belt (Halvorson et al. 1988, p. 111; Fischer et al. 2009, p. 783). Thus, fog could help buffer species from extinction brought on by climatic change, as evidenced by the elevated levels of endemism along the coast of Baja California and on the Channel Islands (Vanderplank 2014, p. 5). Climate on the Channel Islands continues to support paleoendemic plants, such as Lyonothamnus, which once was widespread in the southwest of North America and is thought to have been extirpated on the mainland as conditions became warmer and drier (Bushakra et al. 1999, pp. 473-475). However, coastal fog has been decreasing in southern California in recent decades, possibly due to urbanization (which would not affect SCI) or climate change (Williams et al. 2015, p. 1527; Johnstone and Dawson 2010, p. 4537; LaDochy and Witiw 2012, p. 1157), and costal cloud cover and fog are poorly addressed in climate change models (Qu et al. 2014, p. 2603-2605). Warming projections in California, particularly the possibility that the interior will experience greater warming than the coast (Cayan et al. 2012, p. 7), suggest that the fate of coastal fog is uncertain (Field et al. 1999, pp. 21–22; Lebassi-Habtezion et al. 2011, p. 8-11).

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Iacobellis et al. (2010, p. 129), however, showed an increasing trend in the strength of low-level temperature inversions, which suggests that the marine layer is likely to persist and may even increase. Recent work examining projected changes in solar radiation and cloud albedo show projected increases in cloud albedo during the dry season (July–Sept) and decreases during the wet season (Nov–Dec, Mar–Apr) (Clemesha 2020, entire). The summer projections mean an increase in fog and low clouds the decreases in the winter likely reflect a decrease in a combination of precipitation and fog (Clemesha 2020, pers. comm.; Clemesha 2020, entire). Such a scenario would moderate the effects of climate change on the Channel Islands and would be expected to reduce its potential threat to island plants, including Castilleja grisea. Dry season low clouds and fog are particularly important to plant growth, survival and population dynamics in arid systems through both a reduction in evapotranspiration demand and potentially water deposition (Corbin et al. 2005, p. 511, Johnstone and Dawson 2010, p. 4533, Oladi et al. 2017, p. 94). Predicting impacts to Castilleja grisea due to climate change are further complicated by the timing of increased or decreased rainfall; wetter conditions in the winter and early spring can lead to more growth early in the season which can provide more fuel for fire later. However, wetter summers and falls can prevent the fuel from drying out enough to burn (Lawson 2019, pers. comm.). Changes in temperature or rainfall patterns also has the potential to affect biotic interactions, such as decoupling the timing of plant phenology versus insect activity. Therefore, making predictions about future fire patterns as affected by climate change is difficult. We focus on a 20 to 30-year window, in which we do not expect major impacts to C. grisea from these long-term effects of climate change. However, in this short-term 20 to 30-year window, climate change may result in more frequent or severe fires, heavy periods of rainfall that could lead to major erosion events (see Section 5.2), or periods of drought (Kalansky et al. 2018, p. 10).

Summary The impacts of predicted future climate change to Castilleja grisea remain unclear. While we recognize that climate change is an important issue with potential drastic effects to listed species and their habitats, information is not available to make accurate predictions regarding its effects to C. grisea (USFWS 2012, p. 29121). However, given the timeframe presented in climate change studies, a major impact on C. grisea from climate change is unlikely to occur in the next 20-30 years, although there may be short-term climate impacts, such as increased fire frequency and/or severity, increased periods of drought, or periods of heavy rainfall.

4.6 Other Threats It is likely that granivores eat the seeds of Castilleja grisea, but it is difficult to study. Two introduced species, Gambel’s quail (Callipepla gambelii) and Chukar (Alectoris chukar), are likely eating some quantity of seeds; however, given the growth trends of C. grisea, seed consumption does not appear to be a threat, and population-level impacts from granivory are unlikely. There are no known host-specific parasites on C. grisea. Fungal pathogens such as Phytophthora can enter wildlands but is not currently documented on SCI. The Navy’s Biosecurity Plan (US Navy 2016) will minimize the risk of such a pathogen arriving.

4.7 Summary of Factors Influencing Viability The habitat for Castilleja grisea is threatened by destruction and modification associated with land use, erosion, the spread of nonnatives, fire, and fire management (USFWS 2012, p. 29119). To help ameliorate these threats, the Navy implements a fire plan (US Navy 2009) to

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address fire-management. The Navy addresses erosion and targeted removal of invasive species, in general, through the INRMP, addresses training-related erosion through the Erosion Control Plan, and addresses further introduction of invasive species through implementation of the biosecurity plan (US Navy 2013a, entire; US Navy 2013b, entire; USFWS 2008, pp. 1–237; US Navy 2016, entire). In our most-recent review of the status of Castilleja grisea, we considered that land-use both in terms of ground-disturbance and wildfire remained threats to recovery (USFWS 2012, p. 29121-29122). As noted above, most of the population of C. grisea falls outside of designated training areas and hence, except for those that may remain within the Impact Areas (i.e., Horse Beach Canyon), direct impacts to the population are minimal. Further, neither naturally occurring erosion nor that induced by human activities has affected any documented occurrence of C. grisea to date. Through implementation of the island-wide conservation measures applied to project design, road-maintenance and repair, and the Erosion Control Plan to address training- related erosion, this threat is no longer considered significant across the range of C. grisea. While the full impact of invasive species on Castilleja grisea is unknown, the effects are likely minimal or localized, given the expansion of C. grisea on the island despite the presence of invasive species. Natural resources managers have been successful at decreasing the prevalence of particularly destructive nonnatives; while specific efforts may or may not directly impact C. grisea, the significant efforts that the Navy makes to prevent the expansion of more invasive species (listed above) into habitat areas constitutes a significant benefit to the island ecosystem overall. Because C. grisea is a generalist with regards to host-selection, invasions of some non-native species may not necessarily adversely affect it, although degradation of natural ecosystems is not desirable and is contrary to the goals of ecosystem management expressed in the INRMP. Future impacts from fire remain uncertain. Fires are typically small, of low severity, and infrequent, and given they are most often ignited due to training, their typical locations are somewhat predictable. However, the fire that burned the eastern escarpment of SHOBA in 2017 was severe and many individuals of Castilleja grisea were lost, though post fire monitoring showed at least 20% of plants survived the fire and indicates that new individuals have sprouted since the fire. Fire management includes the installation of fuelbreaks and fire-suppression and is intended to reduce the spread of fire from designated training areas and to reduce ignition probability. The 2009 fire plan helps inform strategic decisions for training using live fire or incendiary devices, and the Navy reduces activities liable to cause fire during fire-season. Climate change may influence this species by affecting germination, persistence of adult plants, or the host-plant community if drought or increasing temperatures result in significant changes in vegetation communities on SCI. However, the magnitude of this rangewide threat and how it may affect this taxon is unknown at this time, but significant impacts to Castilleja grisea from climate change are unlikely to occur in the next 20 to 30 years. Potential changes to military training and testing on SCI are being considered, and changes that would affect Castilleja grisea are currently unknown. For instance, future training may include expansion of or additions to terrestrial designated training areas, introduction of new training methods, equipment, and activities that would affect fire frequency, fire severity, or soil erosion. While military training on SCI has been and will continue to be dynamic as it evolves to meet new requirements, changes are expected to be incremental, as they have been in the past. Such changes are subject to environmental review under applicable laws and regulations,

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including NEPA and ESA, and impacts to federally listed and sensitive species will be addressed. Therefore, we consider the main threats to Castilleja grisea to be: 1) training impacts to individuals located within the Impact Areas, AVMAs or TARs, 2) impacts from training or erosion to individuals within 100 ft of a road or 50 ft of the AVMR (to account for troop movements as well as erosion potential), and 3) impacts from fire to individuals that lie within areas most likely to burn. No individuals currently exist within the AVMAs or within 50 ft of the AVMR. While other threats to C. grisea exist to various degrees throughout its range (invasive grasses and other species, potential of trampling within the SWATs, IOA, or elsewhere, erosion events, etc.), we consider these threats to be minor enough that they will not have major impacts to the species. Looking at each of our main threats by watershed, we found that 65 watersheds (75%), totaling 35,702 individuals (85%) had either zero or low total threats (Table 13 in Appendix A). Watersheds with low total threats were defined as those where potential impacts from roads, training, or fire frequency (assessed as fire acreage that burned in last 15 years) did not potentially threaten 50% or more of the number of locations, individuals, or for the case of fire, percent of the area within each watershed (Table 13. in Appendix B). We assumed that presence in an AVMA watershed is a low-level threat, unlikely to threaten the locations present; even if erosion became an issue in these watersheds, individuals would have to be within the path of erosion within the watershed to be impacted, as the entire watershed is unlikely to erode. We assumed that presence in an Impact Area is a moderate threat, due to fire and ordnance. We assume that if fires follow a similar fire pattern in the future, then watersheds that burned before have a higher risk of burning again. There are 38 occupied watersheds where no fires have burned in the past 20 years, and 30 more where fires in the last 20 years burned less than 50% of the watershed’s area (Table 13 in Appendix A). Therefore, we found that 39% of watersheds are located in areas with no identifiable major threats and represent half of the total number of individuals on SCI. Only 25% of watersheds comprising 15% of individuals are associated with a threat that could potentially adversely impact 50% or more of the locations, individuals, or area within the watershed (Table 6, Table 13 in Appendix A). Most of the watersheds with no threats are small and along the eastern escarpment, yet these areas still account for over half of the population; most of the watersheds with moderate threats are due to fire and are therefore in SHOBA (Figure 14).

Table 6. Numbers and percentages of watersheds and individuals assessed to have varying levels of threats: none, low (threats that could potentially affect <50% of the locations, individuals, or area within the watershed), or medium (threats that could potentially affect ≥50% of the locations, individuals, or area within the watershed). Threats identified include locations or individuals near a road or in the TARs or Impact Areas, and percent of the watershed area that burned once or >1 time in the past 20 years (1999– 2018). Further, AVMA watersheds are considered to have a low threat level, whereas watersheds in the Impact Areas are assumed to have a moderate threat level. Watersheds Individuals Threats Watersheds Individuals (%) (%) none 34 20,981 39% 50% low 31 14,721 36% 35% moderate 22 6,402 25% 15%

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Figure 14. Representation of locations of watersheds where no threats exist to Castilleja grisea (CAGR), a low level of threats exist to the watershed (threats could potentially affect <50% of the locations, individuals, or area within the watershed), or a moderate level of threats exist to the watershed (threats could potentially affect ≥50% of the locations, individuals, or area within the watershed). Threats identified include locations or individuals within 100 ft of a road or the AVMR, in the TARs, Impact Areas, and AVMA watersheds, and percent of the watershed area that burned once or >1 time in the past 20 years. Further, AVMA watersheds are considered to have a low threat level, whereas watersheds in the Impact Areas are assumed to have a moderate threat level.

SECTION 5 –CURRENT CONDITION

In this chapter, we describe the current condition of Castilleja grisea using our definition of the current distribution (Section 2.6). We describe the current condition using the 3Rs based on the species’ current distribution, population size, and trends.

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5.1 Populations and Management Units Resiliency is typically measured at the population level. While we consider that Castilleja grisea represents a single population, as it is widespread on the island with no natural division in its range (USFWS 2013, p. 45437), for monitoring and tracking the population in the future, we noted that a delineation of the population into watershed units would be useful, and such a delineation could further help to quantify threats across the range. Watersheds have been suggested for use in delineation for monitoring purposes by the Navy (Vanderplank et al. 2019, pp. 6–7), as every point on the island can be easily assigned to a watershed and watershed boundaries on SCI are not expected to change significantly during the 20 to 30-year time frame of this analysis. We divided the species range into watershed units to assess resilience. These units are not meant to represent “populations” in a biological sense; rather, these units were designed to subdivide the species range in a way that facilitates assessing and reporting the variation in current and future resilience across the range. In this document, we assessed the species’ ability to withstand stochastic events in each watershed, and how these occupied watersheds contribute to the viability of the entire island population (the species). Note that this way of delineating management units within which to measure resiliency does not follow the methods used in the 2013 downlisting rule (USFWS 2013, p. 45407) and it is therefore not directly comparable. However, 87 watersheds that are represented here correspond to the 28 extant occurrences from the downlisting rule in Appendix C for cross-referencing purposes (Table 15).

5.2 Methods for Estimating Current Condition To assess the resiliency of Castilleja grisea, we assessed the overall condition of the population by evaluating occupancy, locations, and individuals within each watershed. We also examine population trends which indicate the ability of C. grisea to withstand and recover from stochastic events. Using our assumptions in our analysis of the current distribution of the species (Section 2.6), we defined the species’ current resiliency based on the locations at which the species has occurred within the past 15 years as this is considered a time-frame over which persistence, even absent verifying survey information, can likely be assumed. We based this assumption on the knowledge that no destructive impacts to occupied habitat have occurred across the majority of the range of this species. Resiliency was considered higher for plants within watersheds supporting a greater number of individuals over time; however, if all of the individuals within a watershed were in just one location, we assumed that they are less resilient than a watershed with the same number of individuals that are spread out across multiple locations, as plants will be more likely to persist through stochastic events if one localized event is unable to affect all the plants in the entire watershed. Since the majority of the survey data considered current was collected, there have been two fire seasons on SCI with fires that were ranked as moderate to high severity and therefore had the potential to kill adult plants. While some post-fire monitoring has shown that at least some Castilleja grisea individuals have persisted and others likely have become established in the burned areas since the fire, it is unknown what percent of the total plants were lost. While the actual percentage of existing individuals that survived is unknown, from the 2019 survey data, we used the 2019 survey data to estimate that at least 20% survived, while others may have been missed by surveyors. Therefore, we adjusted numbers of individuals that fall into these burn

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polygons downward to account for the unknown response to these severe fires that occurred after the count data were collected.

Within individual watersheds To evaluate the resiliency of Castilleja grisea within individual watersheds, we assessed the following:

Number of individuals: the minimum conservative estimate of the number of locations and current population within each watershed based on the methodology outlined in Section 2.6. Watersheds occupied at just one location were noted.

Severe fire: the number of locations and individuals potentially adversely affected by the 2012 and 2017 fires that were assessed as fire severity class 1 (completely burned) through severity class 3 (moderately burned). These fire seasons were the only ones where the fires were of this severity, which has the ability to kill some or all shrubs. Plant surveys in 2019 confirmed that Castilleja griesea still occur within these fire polygons; some existing plants were either unburned or are respouting, while others may have established themselves since the fire. To account for the unknown effects of this fire, we determined the number of individuals within each watershed’s population that fell into the burn polygons and therefore may have been affected. We then modeled the effect at the highest expected percent lost as a worst-case scenario and removed 80% of those individuals.

Island-wide To evaluate the resiliency of the overall island population, we assessed the following:

Trends (counts over time): the trajectory of the population based on the best scientific data through counts of individuals over time.

Number of occupied watersheds: the number of watersheds that are currently occupied.

Number of individuals: the minimum conservative estimate of the current population, using the methods described in Section 2.6. Due to the time that has elapsed since the extensive surveys, we are unable to confirm that all of these individuals and groups still persist; however, using knowledge of the plants’ biology, expert opinion, and personal observations, we have reason to believe that the majority of these still exist or have been replaced over time. While some of these locations may have disappeared, especially the ones with fewer individuals, it is equally likely that other locations have been established and individual counts have grown at many locations, as well.

5.3 Current Condition Results Within individual watersheds. Number of individuals: Nine of the 87 occupied watersheds have a local population of under 10 individuals. Thirty watersheds have fewer than 50 individuals. Well over half, 53 watersheds, have 100 or more individuals, and over one quarter, 22 watersheds, have over 500 individuals (Table 13 in

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Appendix A). Twenty-one watersheds (24%) have just one documented location within the watershed.

Severe fire: Twenty-two of the 87 occupied watersheds had individuals that may have been affected by moderately to high severity fires that burned during the 2012 and 2017 fire seasons. Fewer than 10% of the individuals were potentially affected in one watershed, fewer than 50% of the individuals were potentially affected in 7 watersheds, over 90% of individuals were potentially affected in 10 watersheds, and all of the individuals in 4 watersheds were potentially affected (Table 7). Removing 80% of these potentially affected individuals yielded new population estimates for these watersheds that were greatly reduced for many and extirpated in one watershed (Table 7).

Table 7. Occupied watersheds that may have lost Castilleja grisea during the 2012 and 2017 fire seasons where fires burned at a severity that can kill shrubs. Percentages are given for the numbers of individuals that could have been affected in each severity class, as well as the total percent of individuals that may have experienced negative effects of the fire, and the resulting adjusted estimate of the total individuals. Total Severity Adjusted Watershed Individuals 1 2 3 Total % Individuals 1116 1,418 42% 42% 944 1118 201 12% 12% 181 1119 693 5% 81% 86% 215 1123 141 100% 100% 28 1126 117 51% 51% 69 1131 1,852 97% 97% 412 1135 416 63% 63% 207 1137 565 91% 91% 155 1139 488 100% 100% 98 1141 2,487 48% 48% 1,525 1142 101 1% 1% 100 1146 260 94% 94% 65 1148 51 98% 98% 11 1149 660 98% 98% 144 1159 217 5% 42% 19% 66% 102 1160 494 45% 45% 315 1161 14 29% 29% 11 1171 5 100% 100% 1 1172 20 100% 100% 4 1178 588 85% 85% 188 1179 228 21% 21% 190 1181 32 100% 100% 6

Due to the patchy nature of fires and because these methods do not account for new individuals that have established since the fire, populations in these watersheds may be higher.

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Island-wide Number of occupied watersheds: There are 216 watersheds delineated on SCI, and our current distribution of Castilleja grisea encompasses 87 of these.

Number of individuals: Our assessment of the current distribution of Castilleja grisea includes 601 locations representing 48,181 individuals (Table 8). Counting only the most recent data years, 2011 through 2014, a total of 367 locations and 35,404 individuals are represented. The total population drops to 42,104 individuals after accounting for the effects of the 2017 fire.

Table 8. Total locations and individuals considered current, broken down into survey points retained by year. Our methodology estimates approximately 48,181 individuals at 601 locations. Year Locations Individuals 2004 26 952 2005 78 3,262 2006 48 3,276 2007 15 586 2008 7 239 2009 22 2,624 2010 38 1,838 2011 262 21,162 2012 74 10,532 2013 30 3,701 2014 1 9 Total 601 48,181

Trends (counts over time): As reported in Section 2.6, counts of individuals have increased over time with each survey effort, from approximately 1,000 at the time of listing to 31,694 in 2011–2012 (Table 1). We cannot be sure to what extent the growth is attributed to differences in survey effort or survey extent, but we are certain that the population has grown significantly since listing. Survey data indicates that the number of occupied watersheds, locations, and number of individuals have increased over time (Table 1, Table 2, Figure 5).

5.4 Current Population Resiliency Trends indicate that the population of Castilleja grisea on SCI has been increasing over time and withstanding current stochastic effects such as drought cycles, impacts from fire, erosion, or military training and land use, and the presence of nonnative invasive species. Therefore, to quantify resiliency, we used the number of individuals within each watershed. We first assessed the resiliency of each watershed, and then scaled up to the entire population on the island. We binned our assessed resiliency scores by watershed based on number of individuals; these breakpoints are based loosely on expert opinion but are mainly for visualization and have no verifiable biological meaning. Resiliency scores are as follows:

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• Very high— watersheds with >500 individuals. • High— watersheds with 100-500 individuals. • Moderate— watersheds with 10-99 individuals. • Low— watersheds with <10 individuals.

However, for any watershed where all Castilleja grisea occurred in just one location, we lowered the resiliency score by one level. Having all the individuals in just one location means that a single localized impact could extirpate that watershed’s population, regardless of how many individuals are present. Resiliency scores for individual watersheds can be found in Table 13 in Appendix A. Of the 87 watersheds currently estimated to be occupied, 16 (18.4%) are considered very highly resilient, 32 (36.8%) are considered highly resilient, 19 (21.8%) are considered moderately resilient, and 20 (23.0%) are considered to have low resiliency (Table 10). When we scale this up to the entire population, we estimate the current population at 42,104 individuals, after accounting for the effects of the 2017 fires. We estimate that 48 watersheds are high to very highly resilient and account for over 96% of the entire population. Given the population trends and trajectory, the overall population has adequate resiliency to sustain itself in the presence of the current level of stochastic pressures and threats and the current level of conservation and management efforts. Twenty watersheds are considered to have low resiliency, but these account for less than 1% of the total island-wide population (Table 10; Figure 15).

Table 9. The number of watersheds that fall into each of our resiliency categories, the numbers of individuals the watersheds in each category accounts for, and the percent of the total island wide population represented. Watersheds Individuals Percent Total Very High 16 32,207 76.5% High 32 8,760 20.5% Moderate 19 889 2.1% Low 20 248 0.6%

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Figure 15. Current resiliency of Castilleja grisea (CAGR) (based on estimated number and distribution of individuals) by watershed.

5.5 Current Species Representation Genetic data and species distribution on SCI suggest that there is just one population of Castilleja grisea. However, genetic work indicates that this population is genetically diverse. Genetic data (i.e., private alleles) suggest that historically, there were likely high rates of gene flow between groups, causing the genetic similarity found between occurrences by Helenurm et al. (2005, p. 1226). Therefore, even though there is just one representative unit, the species appears to have relatively high genetic variation. It occupies habitat at varying elevations and slopes, both east- facing and west-facing, and throughout the southern two-thirds of the island (Figure 6). It also occupies different habitat types across the island (Figure 3), indicating that it has environmental plasticity and adaptability. While we do not know the historical distribution of this species, it is unlikely that it has lost much of its historical range or habitat diversity. Thus, we expect the

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species should be able to withstand potential short-term changes in environmental conditions or catastrophic pulse events, such as trampling, major erosion events, or severe fires.

5.6 Current Species Redundancy There are 86 watersheds currently estimated to be occupied by Castilleja grisea ranging across the southern two-thirds of the island, whereas only 15 were known to be occupied between 1980 and 1989 (Table 2). The number of individuals has grown substantially since listing, and the majority of the current individuals are located in areas that infrequently experience fire and have no major threats (Figure 12, Table 6). Given the population size and distribution, and considering the likely potential catastrophic events, we envision that only an unusually severe event could foreseeably threaten the species viability. A catastrophic fire, a major erosion event (such as caused by periods of heavy rainfall), or a severe drought are the most plausible potential impacts; an outbreak of an invasive, predatory, or pathogenic species is also possible but highly speculative. We expect that even a large, severe fire would be unlikely to affect a significant portion of the island; however, the population is especially dense along the eastern escarpment. A large, severe fire that burned a substantial portion of this or other high- density areas could have significant effects to the population size, as was seen with the 2017 fire, which reduced the population by an estimated 13%. While only an extreme, prolonged drought could wipe out the species entirely, the effects of multiple, severe drought years, coupled with other stressors, could have substantial impacts to species viability. A severe drought, for instance, has the ability to impact the vegetation island-wide, although drought impacts would have both an elevational gradient and an east/west difference due to prevailing wind direction, insolation and evapotranspiration, and the presence and persistence of fog. Given C. grisea’s wide distribution, we’d expect at least some individuals would be able withstand the drought, by collecting adequate fog moisture or tapping water reserves in the soil. However, depending on the length and severity of drought, impacts to the species could be substantial. Like all endemics, C. grisea has a small range and is confined to SCI and would be unable to disperse elsewhere. While the species is numerous, impacts to areas where the species is particularly numerous (such as the eastern escarpment) could decrease the population size substantially.

SECTION 6 – FUTURE CONDITIONS AND VIABILITY

We have considered what Castilleja grisea needs for viability and the current condition of those needs (Chapters 2 and 5), and we reviewed the factors that are driving the current, and future conditions of the species (Chapter 4). We now consider what the species’ future condition is likely to be. We apply our future forecasts to the concepts of resiliency, representation, and redundancy to describe the future viability of C. grisea. Using our analysis of the factors influencing viability in Section 4, we reevaluate the current threats to Castilleja grisea. In 2008, SCI completed environmental analyses (2008 EIS/BO) to support new and increased training activities on the island, the effects of which were not well known. Since the 2013 rule, many of the potential effects of that training expansion have not been realized, and through an Erosion Control Plan (US Navy 2013b, entire), fire management plan (US Navy 2009, entire), and the INRMP (US Navy 2013a, entire), the potential for those effects are reduced.

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6.1 Introduction Since the removal of feral browsers and grazers from SCI by 1992, few threats exist to the viability of Castilleja grisea on the island, and there are many ongoing management efforts designed to minimize these threats. The species currently occupies a broad distribution on the island and exists mostly in locations that occur outside the training areas, are inaccessible to vehicular and foot traffic, have burned infrequently, and have not experienced erosion events. The species exists in large numbers in areas where there are no or few threats to its habitat. It is unknown whether C. grisea generally occurs infrequently within the training areas, areas that burn frequently, and other highly used areas because the plants are less able to become established there, or whether it is because they have just not yet dispersed into those areas. The factors that appear to have the most potential to impact species viability in the future are land use, fire, and climate change, including potential compounded effects. However, we are unable to address the full impacts of climate change because how climate change will affect SCI in the long term remains unclear, and most importantly, the persistence and timing of the fog layer, which provides moisture and a refuge from the full impacts of warming, is unknown. However, based on our review of the literature and models on climate change, we assume that climate change will not have major effects on Castilleja grisea in the next 20 to 30 years. We do account for the possibility of more frequent or severe fires, which could be a short-term impact of climate change, a product of increased military training, or both. Therefore, we consider the future of C. grisea in terms of its threats and conservation efforts over the next 20 to 30 years. Similarly, we cannot predict the future of fire on the island, but we do know what the fire pattern has been in the past. Fire seasons generally have consisted of low-severity fires; however, in 2017, one fire was of an unprecedented severity for its size and occurred over a large area in which fire had not been documented previously. Whether this fire was an outlier or whether severe fires will become more common in the future is unknown, though fire management was modified following the fire to minimize the likelihood of such a burn in the future. If training increases, or if fires become more frequent for other reasons (climate change and weather/precipitation patterns, invasive grasses, etc.), we would not expect the current fire pattern to change, as we would not expect the locations of live fire use to change, but increased use of these areas might increase the frequency of fires. While it is possible that future changes or impacts might alter the footprint of where fires generally burn, this type of threat is not expected and thus is not easily predictable; thus, the sort of future threats that could alter the fire footprint is addressed in Sections 6.5 and 6.6, under Representation and Redundancy. Land use could have potential impacts to Castilleja grisea due to military training and other uses, specifically where individuals exist within boundaries of a TAR or Impact Area, within an AVMA watershed, or near a road (where individuals could experience other road impacts such as erosion). While the plants known to exist in these areas and near roads have persisted currently, future increases in the amount or location of training (including increased foot traffic and maneuvering along roads) could affect the individuals within these locations. Threats associated with these areas, while more likely within the training areas than near roads, were accounted for. While impacts from fire, training, and roads are somewhat likely to occur and the location of these impacts can be predicted, severe erosion events are less likely and it is harder to predict their location. Therefore, we considered severe erosion events as a catastrophic impact and will account for it in our assessment of redundancy and representation.

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Therefore, to assess the future viability of Castilleja grisea, we considered several future scenarios that encompass the uncertainty associated with fire and military training, as well as uncertainty in the levels of recruitment over time.

6.2 Methods To assess future resiliency, we addressed the following metrics within each watershed and then scaled up to the population as a whole:

Growth and recruitment: Abundance in existing watersheds: Based on survey data and trends and the location of new individuals in regularly visited areas, the population of Castilleja grisea appears to be increasing and expanding. However, the rate and patterns of recruitment are unknown. Existing data do not indicate at what rates groups of plants expand over time, where expansion is occurring, or areas that may be decreasing. While the population has grown in the past several decades, it is unknown whether this level of growth could be maintained into the future due to unknown habitat limitations, threats, or other factors. Therefore, we conservatively modeled recruitment at two levels: • Moderate recruitment: additional 25% individuals added to the watershed. • Low recruitment: additional 5% individuals added to the watershed

These estimates are based solely on expert opinion of a conservative estimate of expected future growth. The overall known population has roughly tripled each decade since the removal of feral herbivores on the island. Therefore, these population growth estimates should be biased low. Further, in our future scenarios, we modeled recruitment before we model threats; therefore, all new recruits were subject to the threat analysis. In reality, some new recruitment would occur after some impact occurred. Therefore, this further kept our estimates biased low. Some watersheds may recruit at closer to the higher level and some may recruit at closer to the lower level.

New watersheds: Over time, Castilleja grisea has both increased its numbers within watersheds and has become established or sprouted from the seed bank in new watersheds. After the removal of feral browsers and grazers when the island began to recover, C. grisea was able to become established in watersheds where occupation had not been documented previously. Between 1999 and 2009, 40 new watersheds were observed to be occupied by C. grisea. From 2009 to 2014, 19 new watersheds were discovered to be occupied. While we expect that new watersheds will become occupied (or recently extirpated ones will become repopulated), we also expect that this growth will slow down, as nearby unoccupied watersheds become occupied. Currently there are 79 unoccupied watersheds that border an occupied one; while the habitat types and soil types in these watersheds do not appear to limit recruitment, we cannot predict how likely they are to become occupied. We do not know what the historical distribution of C. grisea was, or how much recruitment is from the seed bank. While not impossible, we cannot expect the species to continue expanding into new watersheds at the current rate, but it is also unlikely that expansion will cease altogether, especially on the eastern escarpment. Therefore, for the next 20 to 30 years, we model recruitment into new watersheds at two levels: • Moderate recruitment: 10 new watersheds at the end of 20 to 30 years. We will assume these will recruit <10 individuals in 20–30 years (low resiliency).

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• Low recruitment: 5 new watersheds at the end of 20 to 30 years. We will assume all of these will recruit <10 individuals in 20–30 years (low resiliency).

Fire frequency and severity: Frequent, recurrent fire represents a potential threat to Castilleja grisea. While we cannot predict the future fire patterns, past fire data and trends help us project potential impacts from fire in the future. Because fires tend to ignite and occur in the same areas (within the Impact Areas and throughout SHOBA), we used the fire footprints from the past 20 years (1999-2018, which encompasses the time period since fire management was initiated) to model where future fires are likely to burn. We modeled the impacts of fire both as if the 2017 fire season was an anomaly, and as if the 2017 fire season is indicative of a change in the fire severity pattern and fires will increase in frequency or severity in the future due to a training increase, climate impacts, or both. Using the percentage of each occupied watershed that has burned once and more than once within the last 20 years, we calculated the total number of individuals that could be affected by fire in that watershed. For instance, if 50% of the watershed has burned in the last 20 years, we assumed that 50% of the individuals of C. grisea could be affected by fire in the future. This helped account for fires that might burn in parts of watersheds where they have not burned historically. We assessed areas that burned >1 time and 1 time separately. While we know that C. grisea can withstand fires and can colonize areas that have burned in the past, evidenced by their presence within the areas that have burned in the last 20 years, the actual fire tolerance of C. grisea and likelihood of persisting through future fires is unknown. Severe fire has potentially reduced the number of individuals in an area by 80%. Therefore, we modeled a range of fire effects, assuming that fires will neither spare 100% nor eradicate 100% of the individuals in any burn polygon. To capture this uncertainty, we modeled future fire impacts as:

• Status quo fire severity: We assume that 25% of individuals that could be affected by more than 1 fire (area that burned >1 time) perish and are not replaced in the population. We assume plants persist in areas that burned just once. • Increased fire severity: Assume that 50% of individuals that could be affected by more than 1 fire (area that burned >1 time) perish. Further, we assume that 25% of individuals that could be affected by 1 fire (area that burned 1 time) perish and are not replaced in the population. • Extreme fire severity: Assume that 75% of individuals that could be affected by more than 1 fire (area that burned >1 time) perish. Further, we assume that 50% of individuals that could be affected by 1 fire (area that burned 1 time) perish and are not replaced in the population.

The status quo scenario attempts to model the current rarity of high-severity fires, yet still bias the effect high. These models assume that for some percent area of each watershed that experienced a fire between 1999 and 2018, those watersheds would lose 25–50% of a corresponding percent of their individuals under the increased fire severity scenario. Likewise, for some percent area of each watershed that experienced more than one fire between 1999 and 2018, those watersheds would lose 50–75% of a corresponding percent of their individuals under the extreme fire severity scenario, and 25% of a corresponding percent of their individuals under the status quo scenario. While this does not explicitly model fires that could potentially break out in new areas and burn previously unburned watersheds, it does attempt to account for them by

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assuming some mortality by all fires. Severe fires in previously unburned areas are accounted for in our discussion of population redundancy and representation. Further, these scenarios do not specifically account for new recruitment from the seed bank after the fire, since we modeled recruitment before applying the threats, and therefore, in these scenarios, individuals killed by fire are not replaced in the population. Thus, even if severe fires always remove 80–95% of the individuals on the landscape, we assume that the fires will be patchy, severity will differ from area to area, and at least some of the individuals will be replaced over time. By using 75% as our maximum removed, our estimates of persistence given future fires should not be biased high.

Land Use/Training Training and land use in the AVMA, TARs, Impact Areas, and along the AVMR and roads represent a potential threat to Castilleja grisea. While we cannot predict exactly how land use will change over time, changes in training and land use are common. Using the percent of individuals that occur either within a training area or near a road, we calculated the total number of individuals that could be affected by increased training in that watershed. While we know that C. grisea can withstand some training impacts, evidenced by their presence within the Impact Areas, the actual realized impacts of increased training on C. grisea is unknown. Therefore, to capture this uncertainty, we modeled future training impacts as: • Training stays the same: no impact • Training increase: Assume that 50% of all locations and individuals within 100 ft of roads, within the Impact Areas, or within the AVMA watersheds perish. • Extreme training increase: Assume that all locations and individuals within 100 ft of roads, within the Impact Areas, or within the AVMA watersheds perish.

By modeling these training increases, we attempted to project plausible although unlikely scenarios in which 50% to 100% of all individuals in the Impact Areas, AVMA watersheds and those near roads perish over time. Any changes to training would have to be substantial to affect the species in this way; this assumes that all area within each training area would be utilized and severely degraded. Changes in training on the island may result someday in new training footprints, but the area within them utilized and degraded is unlikely to be as large as the entirety of the current footprints; therefore, we have tried to bias these impacts high. The possibility of training footprints changing dramatically will be addressed in Section 6.6, future redundancy.

6.3 Models and Scenarios We modeled future effects on resiliency over 20 to 30 years, the maximum projection we feel we can project out to before the effects of climate change cause too much uncertainty.

• Scenario 1: Status quo. This assumes same fire severity, and current training impacts (current plants persist under current training). • Scenario 2: Moderate threat increase. This scenario assumes increased fire severity, and increased training impacts. • Scenario 3: High threat increase. This scenario assumes extreme fire severity, and extreme training impacts.

We applied each of these scenarios to the number of individuals considered current in each watershed but used the adjusted numbers for the individuals that are located inside the

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severe 2017 fire polygons. We first adjusted the numbers to reflect population growth and recruitment; we then applied the threats and the associated declines in numbers to the total new number of individuals. We expect that in all of these scenarios, resulting population sizes are biased low. By applying the threats second, we ensured that all new individuals were subject to the modeled threats. In reality, over a 20- to 30-year period, fires or training increases may eliminate individuals, but it is likely that individuals would return and become reestablished in future years. Further, increased training to the point that it impacts 50–100% of the individuals in the training areas and fires that impact such high percentages of individuals in all of the past fire polygons are unlikely. And finally, the current population size on SCI is likely already underestimated. Surveys have not been comprehensive across all potential habitat, as an island- wide systematic survey would be both unfeasible due to terrain, time, and effort required, and plants are further difficult to locate among grasses and other plants. That plants often go undetected is evidenced by the 2019 surveys that located over 800 previously unknown individuals on the eastern escarpment in areas that have not burned (and therefore are probably not all newly established).

6.4 Future Resiliency We again binned our assessed resiliency scores by watershed based on number of individuals, where resiliency is as follows: • Very high— watersheds with >500 individuals. • High— watersheds with 100-500 individuals. • Moderate— watersheds with 10-99 individuals. • Low— watersheds with <10 individuals.

Again, for any watershed where all Castilleja grisea occurred in just one location, we lowered the resiliency score by one level. We did not assume growth affected the number of locations. Population changes within individual watersheds under each scenario can be found in Table 13 in Appendix A. Our methods predict that, in the next 20 to 30 years, the number of occupied watersheds are likely to increase, assuming that the species will be able to colonize new watersheds; at worst, without new colonization, we predict the number of watersheds would decrease by 7 (Table 11). The numbers of watersheds considered highly or very highly resilient stays the same in our most optimistic scenario and decreases by 7 in our most pessimistic. However, the resulting population estimates in all three scenarios do not drop below 38,000 individuals, and the current population estimate is within the range of estimates for the scenarios where additional threats are modeled (Scenarios 2 and 3) (Table 11). In the absence of major threats (Scenario 1), with no factors limiting sustained recruitment, we do not expect any stochastic impacts to affect Castilleja grisea in a significant way over the next 20 to 30 years. We therefore expect that the entire island population is likely to increase in resiliency under Scenario 1. Even under the Scenario 3 with extreme training and fire impacts, despite localized extirpations in some of the northernmost and southernmost parts of its range (Figure 16), the total population still only is projected to potentially see a decrease of about 3,000 individuals island-wide and may increase from current (Table 11). Thus, apart from

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an unforeseen, unprecedented, or catastrophic impact, we expect the island population is very likely to remain resilient to normal stochastic impacts under all future scenarios.

Table 10. The number of watersheds considered of very high, high, moderate and low resiliency and the total estimated population as considered current and in each of our four future scenarios. Watershed numbers in parentheses represent the total watersheds assuming recruitment into new watersheds, with a range from low (5 new watersheds) to high (10 new watersheds) recruitment. Watershed Resiliency Very High High Moderate Low Total Individuals Current 16 32 19 20 87 42,104 Scenario 1 17 31 19 20 (25-30) 87 (92-97) 43,489–51,773 Scenario 2 16 26 24 18 (23-28) 84 (89-94) 40,435–48,137 Scenario 3 14 27 21 18 (23-28) 80 (85-90) 38,078–45,330

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Figure 16. Resiliency estimates by watershed (based on number of individuals) currently as well as under each of our three scenarios. Extant watershed counts do not account for recruitment into new watersheds.

6.5 Future Representation Without continued recruitment into new watersheds, the number of watersheds occupied by Castilleja grisea may decrease under projected impact increases as modeled in Scenarios 2 and 3. However, if our projected recruitment into new watersheds mimics reality, then the number of occupied watersheds and the number of individuals are likely to increase over the next

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20 to 30 years. Without recruitment into new watersheds, few watersheds are expected to be extirpated even in Scenario 3, and the remaining watersheds still cover a broad distribution on SCI. Thus, we do not expect the species to see a major decline in representation. Given this species’ already high genetic diversity and ability to inhabit diverse areas and habitats on the island, we expect the species will continue to have similar levels of representation as current and should continue to be able to withstand any reasonably plausible change in environmental conditions or catastrophic pulse events, such as trampling, major erosion events, or severe fires, under all of the future scenarios.

6.6 Future Redundancy If Castilleja grisea is able to recruit into new watersheds as we expect, then the number of watersheds occupied by C. grisea is likely to increase over time in all but Scenario 3, where there is extreme training and fire impacts. The number of individuals is also expected to increase under Scenario 1 (no additional impacts) and may either increase or decrease by at most ~4,000 individuals over the next 20 to 30 years in the other two scenarios (where new impacts occur), indicating redundancy will also increase. Thus, we do not expect redundancy to change much from current. While the species may become extirpated in the Impact Areas and in watersheds near the northern end of its distribution were fire severity or frequency or training impacts to increase, other nearby watersheds are projected to remain occupied (Figure 16). Thus, we expect that the species will retain its current levels of redundancy to sustain most major catastrophic events, such as unprecedented fires, major erosion events (such as caused by periods of heavy rainfall), or an outbreak of an invasive, predatory, or pathogenic species. Even the most severe of these events would be unlikely to affect the entire island-wide population. Even the largest fires that have ever burned are small in comparison to the range of C. grisea. Severe erosion events resulting from heavy rainfall, a potential effect of climate change, could remove individuals, but this would occur within localized areas. Continued management efforts on the island would make the possibility of an extreme fire, predatory or pathogenic invasion, or major erosion event unlikely. Only an unprecedented, unusually severe or catastrophic impact could threaten the viability of the species. For instance, the effects of multiple, severe drought years, coupled with other stressors, could have substantial impacts to species viability. A severe drought could impact the vegetation island-wide, but we’d expect at least some individuals would be able withstand even severe drought, perhaps by collecting adequate fog moisture or tapping water reserves in the soil. However, depending on the length and severity of drought, impacts to the species could be substantial. A change in the fire pattern could put more individuals at risk of fire, especially in the unlikely event that fires become frequent on the eastern escarpment. Frequent fires on the eastern escarpment could drastically reduce the population, and thus, redundancy. Like all endemics, C. grisea has a small range and is confined to SCI and would be unable to disperse elsewhere. While the species is numerous and occupies a broad range, impacts to areas where the species is particularly numerous (such as the eastern escarpment) could decrease the population size substantially.

6.7 Limitations and Uncertainties In any species status assessment, the process of projecting a population into the future requires making strategic simplifications of reality, accounting for multiple uncertainties, and making informed assumptions when necessary. Our assessment addressed some of the key uncertainties and yielded useful predictions for characterizing the future status of Castilleja

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grisea, and through the use of predictive constructs and multiple scenarios, we captured a range of plausible conditions in the future. However, there are still limitations to these predictions; we outline these uncertainties and assumptions of the analyses below. Our assessment of the current population used data collected between 2004 and 2014 (Table 8), following a rule set designed to prevent overcounting. However, the rule set assumes that numbers of individuals have not changed since they were counted, and that any declines in count numbers are likely to have been replaced elsewhere in the distribution. The reality of the size of the population and the number of currently occupied watersheds is unknown, although there is evidence that the population may in fact be much larger than our estimate (many previously unknown individuals have been located since the data were collected). Our assessment of the impacts of the 2017 fire that burned a portion of the eastern escarpment also relied on assumptions. Absent systematic counts from both before and after the fire, following the same methods and search extent, we were unable to ascertain the full impacts to the individuals in those areas from fire. Survey data from 2019 showed that individuals did still persist in those areas, but the population numbers appeared reduced. We were unable to quantify the amount by which they were reduced; thus, we used the available data to make a conservative estimate and not overestimate the number of surviving individuals. However, again, the true impact of this fire is unknown. Our future scenarios also made several assumptions; first, we assumed that individuals within each watershed will be able to successfully recruit more individuals into those watersheds. Anecdotal evidence exists that recruitment in some groups of plants may be higher than in others; however, in absence of quantifiable data, we assumed recruitment and persistence would be consistent across the island, with number of new recruits calculated as a percentage of the existing number of individuals in each watershed; however, we attempted to use a conservative estimate of this level of recruitment so as to not overestimate growth over the projected timeframe. We also made assumptions regarding how training, fire, and impacts from proximity to roads would affect the numbers of individuals in each watershed where these threats may occur; again, no quantifiable data exists to accurately predict these impacts. Our estimates of these impacts were made in an attempt to not underestimate these threats but instead create worst-case scenarios. Further, we assumed that training, fire, and impacts from proximity to roads would impact the same areas as they have historically; our models do not account for a change to training area footprints or changes to where ignition sources are located or where fires are likely to burn. While we do not anticipate these sorts of changes, they cannot be ruled out. We also assumed that the Navy will continue to manage habitats on the island into the future, continuing their efforts to manage fire, invasive species, and erosion. If the Navy were to cease being good land stewards, our conclusions would likely be invalidated. The final major uncertainty regarding the future of SCI is the impacts of climate change in the long term and drought and fire impacts in the shorter term. While we do not expect climate change to have major impacts to the vegetation on SCI in the next 20 to 30 years, data may change as climate science evolves and new climate models come out. In the short term, drought cycles, which have been a part of the historical climate on SCI, may intensify. The full impacts of rainfall patterns and the future of the fog layer are unknown.

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6.8 Conclusions Despite historical and current land uses, historical drought cycles, historical and current fire patterns, and other existing threats, Castilleja grisea has substantially increased both its distribution and population numbers on SCI since listing. Currently, we expect that C. grisea has adequate resiliency, redundancy, and representation to withstand most of the likely stochastic impacts, environmental changes, and reasonably plausible potential catastrophic events on SCI. Projecting the population into the future, even given extreme impacts from increased fire frequency, fire severity, and training, we find that a substantial proportion of the population occurs outside areas where these threats are projected to occur. Thus, outside of a catastrophic or unprecedented impact and given continued management efforts and land stewardship practices by the Navy, we expect the population will retain somewhat similar levels of resiliency, redundancy, and representation as it currently has.

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______. 2013a. Integrated Natural Resources Management Plan (INRMP) Naval Auxiliary Landing Field San Clemente Island, California. Prepared by Tierra Data Inc. 784 pp. ______. 2013b. Erosion Control Plan for San Clemente Island. Prepared by Science Applications International Corporation, Carpinteria, CA. 132 pp. ______. 2016. Naval Auxiliary Landing Field San Clemente Island Biosecurity Plan FINAL. November 2016. Prepared by ManTech SRS Technologies, Inc. ______. 2017. Updated botanical survey results for three federally listed plants on San Clemente Island: Acmispon dendroideus var. traskiae, Castilleja grisea and Delphinium variegatum var. kinkiense. Prepared by Sula Vanderplank, Kimberley O’Connor, Bryan Munson and Tierra Data, Inc. 32 pages. U.S. Fish and Wildlife Service [USFWS]. 1977. Determination that seven California Channel Island animals and plants are either endangered species or threatened species [endangered: San Clemente loggerhead shrike, Lanius ludovicianus mearnsi; San Clemente broom, Lotus scoparius ssp. traskiae; San Clemente bushmallow, Malacothamnus clementinus; San Clemente Island larkspur, Delphinium kinkiense; San Clemente Island Indian paintbrush, Castilleja grisea. Threatened: island night lizard, Klauberina riversiana; San Clemente sage sparrow, Amphispiza belli clementae]. Fed. Reg. 42: 40682–40685. ______. 1984. Recovery Plan for the Endangered and Threatened Species of the California Channel Islands. U.S. Fish and Wildlife Service, Portland, Oregon. 165 pp. ______. 1997. Endangered and Threatened Wildlife and Plants; Determination of Endangered Status for Three Plants From the Channel Islands of Southern California. Fed. Reg. 62: 42692–42702. ______. 1998. Recovery Plan for Serpentine Soil Species of the San Francisco Bay Area. Portland, Oregon. 330+ pp. ______. 2007. Castilleja grisea (San Clemente Island indian paintbrush) 5-year review: Summary and evaluation. U.S. Fish and Wildlife Service, Carlsbad, California. 19 pp. ______. 2008. Biological Opinion for San Clemente Island Military Operations and Fire Management Plan, Los Angeles County, California (Service File FWS–LA–09B0027– 09F0040). [November, 2008]. ______. 2009. Recovery Plan for Serpentine Soil Species of the San Francisco Bay Area. Sept. 1998. 445 pp. ______. 2011. Endangered and Threatened Wildlife and Plants; 90-Day Finding on a Petition To Delist or Reclassify From Endangered to Threatened Six California Species. Fed. Reg. 76: 3069-3074. ______. 2012. 12-month finding on a petition to downlist three San Clemente Island plant species; proposed rule to reclassify two San Clemente Island plant species; taxonomic correction; proposed rule. Fed. Reg. 77: 29077–29128. ______. 2013. Reclassification of Acmispon dendroideus var. traskiae (=Lotus d. subsp. traskiae) and Castilleja grisea as threatened throughout their ranges. Final Rule. Fed. Reg. 78: 45405–45439. ______. 2016. USFWS species status assessment framework: an integrated analytical framework for conservation. Version 3.4.8, August 2016. ______. 2018. Carlsbad Fish and Wildlife Office, Geographic Information System Analysis, Data and Summary of Procedures.

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Uyeda, K., K. Warkentin, D.A. Stow, J.F. O’Leary, T. Zink, J. Lambert, L. Coulter, R. Snavely, A. Loerch, A. Schurlock, and G. Schag. 2019. Vegetation mapping at NALF San Clemente Island, Naval Base Coronado, California. Final Report. Agreement No.: W9126G-15-2-0034. 38 pages. Vanderplank, S. 2014. Endemism in an Ecotone: From Chaparral to Desert in Baja California, Mexico. Pages 205–218 in Carsten Hobohm, Editor. Endemism in Vascular Plants. Springer Publishing, Dordrecht. Vanderplank, S., K. O’Connor, B. Munson, and D. Lawson. 2019. A Conservation Assessment for Castilleja grisea (San Clemente Island Paintbrush, Orobanchaceae). Rancho Santa Ana Botanic Garden Occasional Publications, Number 17, vi + 34 pages. Wetherwax, M., Chuang T.I., and L. R. Heckard. 2012. Castilleja, in Jepson Flora Project (eds.) Jepson eFlora, http://ucjeps.berkeley.edu/eflora/eflora_display.php?tid=11347, accessed on June 28, 2017. Williams, A. P., R. E. Schwartz, S. Iacobellis, R. Seager, B. I. Cook, C. J. Still, G. Husak, and J. Michaelsen. 2015. Urbanization causes increased cloud base height and decreased fog in coastal Southern California, Geophys. Res. Lett., 42, doi:10.1002/2015GL063266. Wolf. S., B. Hartl, C. Carroll, M.C. Neel, and D.N. Greenwald. 2015. Beyond PVA: why recovery under the Endangered Species Act is more than population viability. BioScience 65:200-207. Yatsko, A. 2000. Of Marine Terraces and Sand Dunes: The Landscape of San Clemente Island. Pacific Coast Archaeological Society Quarterly 36(1): 25-30. Young, N.D., K.E. Steiner, and C.W. dePamphilis. 1999. The evolution of parasitism in Scrophulariaceae/Orobanchaceae: Plastid gene sequences refute an evolutionary transition series. Annals of the Missouri Botanical Garden 86:876–893. Zedler, P.H., C.R. Gautier and G.S. McMaster. 1983. Vegetation change in response to extreme events: The effect of a short interval between fires in California chaparral and coastal scrub. Ecology 64:809–818.

Personal Communications Booker, Melissa (San Clemente Island Natural Resources Manager & Wildlife Biologist). 2019. Documentation of take aways from series of phone calls, document edits, etc. between January and November 2019. Clemesha, Rachel (Scripps Institution of Oceanography). 2020. Email to Dawn Lawson, Re: Progress Report Fog and Coastal Low Cloud Analysis for San Clemente Island. Monday January 27, 2020. Lawson, Dawn (Adjunct Faculty, Biology Department, San Diego State University). 2019. Telephone conversation with T.M. McFarland (Texas A&M NRI), April 2019 and email to Kim O’Connor (US Navy) November 25, 2019. O’Connor, Kim (Conservation Program Manager, US Pacific Fleet). 2019. Documentation of take aways from series of phone calls, document edits, etc. between January and November 2019. McFarland, Tiffany (Senior Research Associate at Natural Resources Institute, Texas A&M University). 2019. Personal observations from trip to San Clemente Island, April 2019. Munson, Bryan (Botany Program Manager, Naval Base Coronado). 2019. Documentation of take aways from series of phone calls, document edits, etc. between January and November 2019.

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APPENDIX A

Table 11. Location points and individuals of Castilleja grisea counted at points where a fire had burned within the past 10 years. Year of last fire and the number of years that have passed since the fire are included. CAGR Year of Years Survey CAGR Last Since Watershed Year Individuals Fire Fire WS_1141 2013 3 2012 1 WS_1118 2011 14 2008 3 WS_1119 2005 11 2000 5 WS_1171 2012 4 2007 5 WS_1146 2005 2 1999 6 WS_1146 2005 20 1999 6 WS_1146 2005 10 1999 6 WS_1146 2005 82 1999 6 WS_1146 2005 6 1999 6 WS_1146 2005 12 1999 6 WS_1149 2005 60 1999 6 WS_1149 2005 25 1999 6 WS_1119 2006 6 2000 6 WS_1146 2005 4 1999 6 WS_1146 2005 28 1999 6 WS_1146 2005 22 1999 6 WS_1146 2005 30 1999 6 WS_1149 2005 202 1999 6 WS_1149 2005 155 1999 6 WS_1114 2005 6 1999 6 WS_1114 2005 14 1999 6 WS_1145 2005 90 1998 7 WS_1145 2005 2 1998 7 WS_1145 2005 16 1998 7 WS_1145 2005 10 1998 7 WS_1145 2005 7 1998 7 WS_1145 2005 3 1998 7 WS_1145 2005 65 1998 7 WS_1145 2005 134 1998 7 WS_1145 2005 10 1998 7 WS_1145 2005 5 1998 7 WS_1159 2006 45 1999 7 WS_1159 2006 65 1999 7 WS_1118 2011 40 2004 7 WS_1145 2005 153 1998 7

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CAGR Year of Years Survey CAGR Last Since Watershed Year Individuals Fire Fire WS_1145 2005 13 1998 7 WS_1145 2005 95 1998 7 WS_1145 2005 31 1998 7 WS_1145 2005 1 1998 7 WS_1145 2005 18 1998 7 WS_1145 2005 15 1998 7 WS_1145 2005 3 1998 7 WS_1145 2005 74 1998 7 WS_1145 2005 16 1998 7 WS_1148 2007 50 1999 8 WS_1149 2007 175 1999 8 WS_1159 2007 42 1999 8 WS_1145 2005 1 1996 9 WS_1145 2005 25 1996 9 WS_1145 2005 2 1996 9 WS_1092 2004 10 1994 10 WS_1082 2004 20 1994 10 WS_1082 2004 2 1994 10 WS_1092 2004 13 1994 10 WS_1092 2004 32 1994 10 WS_1092 2004 8 1994 10 WS_1092 2004 105 1994 10 WS_1126 2009 50 1999 10 WS_1137 2009 22 1999 10 WS_1116 2010 18 2000 10 WS_1116 2010 13 2000 10 WS_1116 2010 20 2000 10 WS_1119 2010 1 2000 10

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Table 12. Occupied watersheds, including the current number of locations and individuals present (adjusted for the 2017 fire season), the percent of locations and individuals near roads, the percent of each watershed that burned in the last 20 years and more than once in that timespan, whether the watershed is in the AVMA or IA, and the projected individuals (within a range given low versus high growth) that will occur in that watershed in 20-30 years under each of three scenarios. Threats are represented as low (gold) and moderate (pink). Numbers of individuals under current and future scenarios are represented as low (pink), moderate (gold), high (light green), very high (dark green) and extirpated (red), depending on population size and number of locations (see Section 5.4 and Section 6.4). Loc.s Ind.s Area Area with Near Near with fire >1 fire in Total Total Roads Roads in last 20 last 20 AVMA Watershed Loc.s Ind.s Adjusted (%) (%) years (%) years (%) or IA Scen 1 L Scen 1 H Scen 2 L Scen 2 H Scen 3 L Scen 3 H WS_1033 1 1 1 0% 0% 30% 0% AVMA 1 1 0 0 0 0 WS_1034 7 460 460 0% 0% 2% 0% no 483 575 481 572 478 569 WS_1035 1 29 29 0% 0% 0% 0% AVMA 30 36 15 18 0 0 WS_1036 1 9 9 0% 0% 0% 0% AVMA 9 11 5 6 0 0 WS_1038 3 10 10 0% 0% 0% 0% no 11 13 11 13 11 13 WS_1040 6 1,056 1,056 0% 0% 0% 0% no 1,109 1,320 1,109 1,320 1,109 1,320 WS_1043 5 249 249 0% 0% 0% 0% no 261 311 261 311 261 311 WS_1045 1 5 5 100% 100% 0% 0% AVMA 5 6 0 0 0 0 WS_1048 7 184 184 0% 0% 0% 0% no 193 230 193 230 193 230 WS_1049 6 85 85 0% 0% 0% 0% no 89 106 89 106 89 106 WS_1050 2 40 40 0% 0% 0% 0% no 42 50 42 50 42 50 WS_1051 2 30 30 0% 0% 0% 0% no 32 38 32 38 32 38 WS_1052 1 1 1 0% 0% 0% 0% no 1 1 1 1 1 1 WS_1053 4 196 196 0% 0% 0% 0% no 206 245 206 245 206 245 WS_1056 1 30 30 0% 0% 0% 0% no 32 38 32 38 32 38 WS_1057 17 314 314 0% 0% 0% 0% no 330 393 330 393 330 393 WS_1058 1 40 40 0% 0% 0% 0% no 42 50 42 50 42 50 WS_1059 1 111 111 0% 0% 0% 0% no 117 139 117 139 117 139 WS_1060 13 530 530 0% 0% 0% 0% no 557 663 557 663 557 663 WS_1061 2 14 14 0% 0% 0% 0% no 15 18 15 18 15 18 WS_1062 13 336 336 0% 0% 0% 0% no 353 420 353 420 353 420 WS_1064 12 298 298 0% 0% 0% 0% no 313 373 313 373 313 373 WS_1065 2 50 50 0% 0% 0% 0% no 53 63 53 63 53 63 WS_1066 19 314 314 0% 0% 0% 0% no 330 393 330 393 330 393 WS_1067 2 480 480 0% 0% 0% 0% no 504 600 504 600 504 600

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Loc.s Ind.s Area Area with Near Near with fire >1 fire in Total Total Roads Roads in last 20 last 20 AVMA Watershed Loc.s Ind.s Adjusted (%) (%) years (%) years (%) or IA Scen 1 L Scen 1 H Scen 2 L Scen 2 H Scen 3 L Scen 3 H WS_1068 2 45 45 50% 67% 0% 0% no 47 56 31 37 16 19 WS_1071 19 6,191 6,191 0% 0% 1% 0% no 6,501 7,739 6,483 7,718 6,466 7,697 WS_1072 26 7,440 7,440 0% 0% 0% 0% no 7,812 9,300 7,812 9,300 7,812 9,300 WS_1077 2 220 220 0% 0% 2% 0% no 231 275 230 274 229 273 WS_1080 1 1 1 0% 0% 25% 0% no 1 1 1 1 1 1 WS_1082 14 659 659 0% 0% 45% 0% no 692 824 614 731 536 638 WS_1083 7 395 395 0% 0% 0% 0% no 415 494 415 494 415 494 WS_1086 3 1,038 1,038 0% 0% 0% 0% no 1,090 1,298 1,090 1,298 1,090 1,298 WS_1087 1 25 25 0% 0% 0% 0% no 26 31 26 31 26 31 WS_1088 11 434 434 0% 0% 2% 0% no 456 543 453 539 451 536 WS_1090 1 1,000 1,000 0% 0% 0% 0% no 1,050 1,250 1,050 1,250 1,050 1,250 WS_1092 33 1,448 1,448 0% 0% 52% 0% no 1,520 1,810 1,322 1,574 1,124 1,339 WS_1094 10 1,568 1,568 0% 0% 1% 0% no 1,646 1,960 1,644 1,957 1,641 1,954 WS_1098 10 88 88 0% 0% 58% 0% no 92 110 79 94 66 78 WS_1099 14 819 819 0% 0% 7% 0% no 860 1,024 844 1,005 828 986 WS_1100 2 150 150 0% 0% 0% 0% no 158 188 158 188 158 188 WS_1101 2 225 225 0% 0% 0% 0% no 236 281 236 281 236 281 WS_1103 4 5,051 5,051 0% 0% 0% 0% no 5,304 6,314 5,304 6,314 5,304 6,314 WS_1104 7 264 264 0% 0% 2% 0% no 277 330 276 328 274 326 WS_1106 18 982 982 0% 0% 41% 1% no 1,027 1,223 918 1,093 809 964 WS_1110 9 41 41 0% 0% 20% 0% no 43 51 41 49 39 46 WS_1111 2 26 26 0% 0% 7% 0% no 27 33 27 32 26 31 WS_1114 22 248 248 0% 0% 73% 59% no 222 264 136 161 49 59 WS_1116 17 1,418 944 0% 0% 76% 38% no 897 1,068 614 731 331 394 WS_1118 11 201 181 0% 0% 89% 72% no 156 185 79 94 3 4 WS_1119 11 693 215 0% 0% 57% 34% no 206 246 155 184 103 122 WS_1120 2 525 525 0% 0% 1% 0% no 551 656 550 655 549 654 WS_1121 6 24 24 0% 0% 44% 2% no 25 30 22 26 19 23 WS_1123 2 141 28 0% 0% 56% 49% no 26 31 18 22 10 12 WS_1126 4 117 69 0% 0% 52% 38% no 66 78 49 58 33 39 WS_1129 1 13 13 0% 0% 67% 0% no 14 16 11 14 9 11 WS_1131 3 1,852 412 0% 0% 61% 32% no 398 474 297 354 196 234

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Loc.s Ind.s Area Area with Near Near with fire >1 fire in Total Total Roads Roads in last 20 last 20 AVMA Watershed Loc.s Ind.s Adjusted (%) (%) years (%) years (%) or IA Scen 1 L Scen 1 H Scen 2 L Scen 2 H Scen 3 L Scen 3 H WS_1135 9 416 207 0% 0% 58% 12% no 211 251 173 206 136 162 WS_1136 9 111 111 0% 0% 73% 54% no 101 120 64 76 27 32 WS_1137 4 565 155 25% 2% 59% 47% no 144 171 99 118 55 65 WS_1139 4 488 98 0% 0% 43% 22% no 97 116 81 96 64 76 WS_1140 1 19 19 0% 0% 0% 0% no 20 24 20 24 20 24 WS_1141 21 2,487 1,525 0% 0% 79% 63% no 1,350 1,607 783 932 216 257 WS_1142 2 101 100 0% 0% 23% 2% no 105 125 98 117 92 109 WS_1145 41 1,200 1,200 0% 0% 62% 29% IA 1,168 1,390 249 297 0 0 WS_1146 12 260 65 0% 0% 83% 72% no 56 67 29 35 3 3 WS_1148 2 51 11 0% 0% 29% 21% no 11 13 10 11 8 10 WS_1149 7 660 144 0% 0% 70% 57% no 130 154 82 97 34 40 WS_1158 1 23 23 0% 0% 82% 70% IA 20 24 0 0 0 0 WS_1159 12 217 102 0% 0% 82% 61% no 91 108 52 62 14 17 WS_1160 8 494 315 0% 0% 42% 19% no 315 375 264 315 214 254 WS_1161 2 14 11 0% 0% 46% 34% no 11 13 8 10 6 7 WS_1171 2 5 1 0% 0% 48% 36% no 1 1 1 1 1 1 WS_1172 1 20 4 100% 100% 38% 33% no 4 5 1 1 0 0 WS_1178 3 588 188 0% 0% 44% 12% no 192 228 164 195 136 162 WS_1179 7 228 190 0% 0% 49% 29% no 185 220 146 174 107 128 WS_1181 1 32 6 0% 0% 49% 0% no 6 8 6 7 5 6 WS_1183 8 150 150 0% 0% 18% 0% no 157 187 150 179 143 170 WS_1184 11 409 409 9% 0% 7% 0% no 429 511 422 502 414 493 WS_1187 11 114 114 36% 65% 1% 0% no 120 143 80 96 41 49 WS_1194 2 43 43 0% 0% 1% 0% no 45 54 45 54 45 54 WS_1196 1 11 11 0% 0% 0% 0% no 12 14 12 14 12 14 WS_1199 1 8 8 0% 0% 0% 0% no 8 10 8 10 8 10 WS_1200 1 19 19 0% 0% 0% 0% no 20 24 20 24 20 24 WS_1201 1 1 1 0% 0% 0% 0% no 1 1 1 1 1 1 WS_1202 8 1,231 1,231 0% 0% 0% 0% no 1,293 1,539 1,293 1,539 1,293 1,539 WS_1216 1 2 2 0% 0% 4% 0% no 2 3 2 2 2 2 Total 601 48,181 42,104 43,489 51,773 40,435 48,137 38,078 45,330

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APPENDIX B

Table 13. Conservation measures for terrestrial plants on San Clemente Island (SCI) as relevant to Castilleja grisea, were taken from the Biological Opinion (BO; USFWS 2008) and Table 3-48 of the Integrated Natural Resources Management Plan (INRMP; US Navy 2013). Taken from Vanderplank et al. 2019, p. 14.

Source Measure Requirements INRMP AVMC-M-7 Require the following measures to reduce the potential for transport and BO of invasive plants to the island. Prior to coming to SCI, military and non-military personnel will be asked to conduct a brief check for visible plant material, dirt or mud on equipment and shoes. Any visible plant material, dirt or mud should be removed before leaving for SCI. Tactical ground vehicles will be washed of visible plant material, dirt and mud prior to embarkation for SCI. Additional washing is not required for amphibious vehicles after 15 minutes of self-propelled travel through salt water prior to coming ashore on SCI. INRMP G-M-1. Continue invasive species control on an island-wide scale, with and BO emphasis on the AVMC, IOA, TARs and other operations insertion areas such as West Cove, Wilson Cove and the airfield. A pretreatment survey to identify areas needing treatment, one treatment cycle and a retreatment cycle (when necessary) will be planned each year to minimize the distribution of invasive species. Where feasible, the Navy will include future construction sites in a treatment and retreatment cycle prior to construction. INRMP G-M-9. Conduct monitoring and control activities for invasive non-native and BO plant species outside of the Impact Area boundaries. Navy installations will prevent the introduction of invasive species and provide for their control per EO 13112. The Navy will identify actions that affect the introduction of invasive species, prevent their introduction, respond rapidly to their control, monitor populations, restore affected native species and their habitat, conduct research and develop technologies to prevent further introductions, and promote public education of the issue. BO A goal will be reducing the percent cover of invasive plants from 2008 the 1992-1993 baseline of 41% on terrace faces and 53% on terrace flats.

INRMP FMP-M-10. Conduct prescribed fire experiments to evaluate their effectiveness and BO in controlling non-native annual plants. INRMP FMP-M-11. Establish post-fire recovery plots to monitor recovery and identify and BO new infestations of non-native invasive plants associated with both wildfire and prescribed fire.

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Source Measure Requirements INRMP FMP-M-12. Evaluate burn areas and prioritize them, as appropriate, for and BO inclusion in the weed eradication program. INRMP To prevent the transfer of invasive species from the mainland to SCI, soil and fill brought to the island are treated with herbicide before importation (INRMP 2012). INRMP Further prevention for the transfer of invasive species to the island is established through the Do Not Plant list maintained by the Naval Facilities Engineering Command, Southwest Botanist and Landscape Architect (INRMP 2012).

INRMP The NRO participates in a Channel Islands biosecurity working group which meets quarterly to discuss and develop measures to prevent non-native species from invading Channel Islands ecosystems, and to share resources and knowledge of potential threats to the islands (INRMP 2012).

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APPENDIX C

Since the 2013 downlisting rule (USFWS 2013), new data collection on the distribution of the plants has been minimal; this SSA includes new location points from 2013 and 2014 that were not included in the distribution considered in 2013. However, despite the lack of new survey data, this SSA will differ from and build upon the 2013 downlisting rule by both reassessing the level of threats perceived in 2013, as well as assessing the data in a different way. This SSA differs from the 2013 downlisting rule in the following ways: • Focuses on location points that were collected within the last 15 years, selected following a ruleset to avoid over- or double-counting, while the downlisting rule considered all historical points in the analyzed distribution. • Includes 31 additional location points representing 3,710 individuals collected in 2013 and 2014. • Moves away from a focus on “occurrences” as defined in the downlisting rule (and further discussed in Section 2.6), and instead focuses on watersheds and the estimated number of individuals in each. The downlisting rule did not indicate the number of individuals at point locations. • Evaluates the current threats to Castilleja grisea; in the 2013 rule, San Clemente Island had recently finalized the 2008 Southern California Range Complex Final Environmental Impact Statement/Overseas Environmental Impact Statement (EIS/OEIS) (US Navy 2008a) and the accompanying Biological Opinion: San Clemente Island Military Operations and Fire Management Plan (BO) (USFWS 2008) which together allowed an increased amount and intensity of training activities on the island (US Navy 2008a, pp. 2–1 to 2–52), the effects of which were not well understood. Since the 2013 rule, many of the potential effects of that training expansion have not been realized despite the training increase. • Evaluates the current threats to Castilleja grisea based on the implementation of several new management plans. An Erosion Control Plan, a new Biosecurity plan, and a new INRMP have been implemented, all aimed to further protect the ecosystems and natural vegetation on San Clemente Island. The way in which species has been discussed or grouped are highly variable. Groups of Castilleja grisea have been described in the literature using many different terms including: point localities, populations, occurrences, and element occurrences. Survey data and opportunistic observation data collected by the US Navy consists of point locations of “contiguous biologically relevant clusters that were unbroken within a line of sight and did not include any obvious barriers to dispersal, pollination, or recruitment,” with an associated count of the number of individuals at that location. These groupings of plants (represented by a point) have been termed “occurrences” (US Navy 2019, entire). In the 2013 downlisting rule, these groupings of plants (hereafter “locations”) were mapped and combined with other locations that fell within 0.25 mi (402 m) of one another and with any corresponding California Natural Diversity Database (CNDDB) polygons at the time of the proposed rule. These combined groups of locations were referred to as “occurrences,” and the listing rule defined 28 occurrences of Castilleja grisea using this methodology (USFWS 2012, p. 29091). Therefore, these occurrences are each composed of one or more groups of plants spread across sometimes large spatial scales (up to and over 4 km across) (Figure 17). The distribution or

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numbers of individuals within these occurrences (represented as polygons) was not specified, although they were created using point locations of C. grisea. Due to these numerous uncertainties, we needed to calibrate this data so that we are using a common metric that could be used to better illustrate the distribution temporally and spatially on San Clemente Island over time. Because the definition and survey methods for groups and locations of individuals has varied over time (such as with the definition of “occurrence”), this SSA focuses on the number of individuals to describe Castilleja grisea currently and to model the species into the future.

Table 14. The canyon names used to represent the occurrences in the 2013 downlisting rule, the element occurrence numbers from the California Natural Diversity Database that were included, and the watersheds that those canyons overlay. Element Canyon Occurrence Watershed ID Thirst 3 1097, 1099, 1100, 1101, 1102, 1103, 1104 Eagle 3 1104, 1110, 1111, 1116, 1117, 1119, 1120, 1123, 1126 1123, 1126, 1127, 1128, 1129, 1131, 1132, 1134, 1135, Bryce 3, 50 1137, 1139, 1140, 1141, 1142 1142, 1146, 1148, 1149, 1159, 1160, 1161, 1168, 1171, Canchalagua 3, 29 1172 Knob 2 1177, 1178, 1179, 1181 Pyramid Head 1 1184, 1194, 1198, 1202 1183, 1187, 1188, 1196, 1197, 1198, 1199, 1200, 1201, Snake 1 1204, 1205, 1206 Upper Chenetti 34, 53 1158, 1166 Horse Beach 25 1145, 1190 China 25, 28, 50 1118, 1145 Red 36 1152 Kinkipar 52 1136 Cave 17, 38 1114 Horse 26, 67 1106, 1121, 1153, 1163 Upper Horse 19 1106 1066, 1067, 1071, 1072, 1083, 1084, 1086, 1087, 1088, SHOBA Boundary north 3 1089, 1090, 1091, 1094, 1095, 1096, 1099

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Element Canyon Occurrence Watershed ID 1052, 1053, 1056, 1057, 1060, 1061, 1062, 1063, 1064, Horton 3 1065, 1066 Lemon Tank 3 1048, 1049, 1050, 1051 Nanny 13, 60 1043 Larkspur 14, 68 1033, 1034, 1040, 1041, 1042, 1043 Box 20, 66 1092, 1098 Upper Norton 20 1082, 1092, 1098 Middle Ranch 24, 65 1082, 1115, 1122 Waymuck 22 1080, 1105 Plain NE of Warren 63, 64 1068, 1077, 1078 Seal Cove Terraces 62 1058 Eel Cove 61 1059 55, 56, 57, Terrace 58, 59, 69 1022, 1035, 1036, 1038, 1044, 1045, 1216

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Figure 17. Approximate boundaries of the 28 occurrences used in the 2013 downlisting rule (USFWS 2013); polygons represent the bounding geometry (minimum convex polygons) around the point locations and element occurrences used to define each occurrence, and the canyon names used to reference each occurrence are provided.

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