POPULATION STATUS OF THE ENDEMIC SAN FRANCISCO DAMSELFLY {Ischnura gemina)

A thesis submitted to the faculty of San Francisco State University AS In partial fulfillment of the requirements for 3 G the Degree 2 0 l b

B f o L Masters of Science * P6s In Biology: Conservation Biology

by Tania Nurith Poliak San Francisco, California January, 2016 Copyright by Tania Nurith Poliak 2016 CERTIFICATION OF APPROVAL

I certify that I have read POPULATION STATUS OF THE ENDEMIC SAN FRANCISCO DAMSELFLY(Ischnura gemina) by Tania Nurith Poliak and that in my opinion this work meets the criteria for approving a thesis submitted in partial fulfillment of the requirement for the degree Master of Science in Biology. Conservation Biology at San Francisco State University.

C. ----- John E. Hafemik Jr., Ph.D. Professor Emeritus of Biology

Professor of Biology

Curator Emeritus Department of Entomology California Academy of Sciences POPULATION STATUS OF THE ENDEMIC SAN FRANCISCO DAMSELFLY {Ischnura gemina)

Tania Nurith Poliak San Francisco, California 2016

Ischnura gemina, the San Francisco forktail damselfly (Family Coenagriortidae) is endemic to the San Francisco Bay area, and is identified by the International Union for Conservation of Nature as a vulnerable species. Research from the late 1970s through the 1990s indicates a decline in the species’ populations. This study completes a comprehensive survey for I. gemina, and the closely related species I. denticollis, to determine the status of both species in areas previously surveyed. The study also seeks to determine the extent that various habitat variables, such as water chemistry and vegetation structure, predict the presence of I. gemina. Data from this study show a dramatic decline in populations of I. gemina since the 1980s and 1990s. In addition, results from this study indicate that I. gemina persists in sites with cooler temperatures and lower salinity than do other ischnuran or coenagrionid species. Finally, this study considers past research related to species conservation in light of climate change, and assesses the long-term viability of I. gemina under climate change. Of key interest is the tolerance for I. gemina under increasing temperatures and sea level rise. The goal for this research is to provide information on the current status of I. gemina and recommendations for its long-term conservation.

I certify that the Abstract is a correct representation of the content of this thesis.

Chair, Thesis Committee Date ACKNOWLEDGEMENTS

I would like to thank my advisor, Dr. John Hafernik, for opening the door to graduate school, introducing me to the world of the “little creatures”, and his support and patience throughout the years of my study. I also thank my other committee members, Dr. Edward Connor, who was instrumental in helping me with the statistics to analyze and understand my data, and Dr. Dave Kavanaugh for his review and guidance. A special thank you to Dr. Misha Leong for her help with R and my understanding of statistics. My field research would not have been possible without the permission of the following landowners for access to their properties; Wendy Eliot, Conservation Director and Shanti Wright, Stewardship Project Manager, Sonoma Land Trust - Estero Americana Preserve; Ben Becker, Director and Marine Ecologist, Pacific Coast Science and Learning Center, National Park Service - Point Reyes National Seashore; Darren Fong, Aquatic Ecologist and Kristen Ward, Ecologist, National Park Service - Golden Gate National Recreation Area; Gary Ingram, Superintendent, Oakland Metropolitan Golf Course; George Gross, Chanslor Ranch; Jackie Sones, Research Coordinator, Bodega Marine Reserve; Janet Klein, Natural Resources Program Manager and Laurie Offenbach. Administrative Assistant, Marin Municipal Watershed District; Nixon Lam, Environmental Affairs, San Francisco Airport and Karen Swain, Swain Biology; Mike Blondino, Parks and Landscape Manager, City of San Mateo; Lisa Wayne, San Francisco Natural Areas Program; J. Rogers, Alameda County Flood Control District; Keenan Foster, Sonoma County Water District; Kathy Biggs. Purchase of field equipment was supported by funds from a San Francisco State University IRA Student Research Grant. My gratitude and thanks to friends who helped me with field work and kept me company on long fields days, and occasionally rescuing me from the mud: Martha Berthelsen, Casey Hubble, Chris Quock, Tamara Williams, Barbara Janis, and Chad Moore. TABLE OF CONTENTS

List of Tables...... vii List of Figures...... viii List of Appendices...... ix

Introduction...... 1 Distribution of Ischnura gemina...... 2 Habitat Characteristics...... 6 Methods...... 7 Population Surveys...... 7 Habitat Characteristics...... 11 Results...... 15 Population Surveys...... 15 Habitat Characteristics...... 16 Habitat Modeling...... 24 Discussion...... 26 Population Status and Trends...... 26 Potential Causes of Species Decline...... 27 Species Persistence under Future Climate Conditions...... 36 Conclusions and Recommendations...... 40 References...... 45 LIST OF TABLES

Table Page

1. Water Flow and Site Substrate Characteristics...... 17 2. Water Chemistry Values ...... 17 3. Significance for means of site chemistry...... 18 4. F-test values for site chemistry values...... 19

vii LIST OF FIGURES

Figures Page

1. Historic distribution of Ischnura gemina from museum records...... 3 2. Distribution of Ischnura gemina 1979 -- 1997)...... 3 3. Survey locations for Ischnura gemina (1980s- 1990s surveys and 2011)...... 5 4. Additional survey locations for Ischnura gemina 2012...... 13 5. Schematic of Vegetation Transects...... 14 6. PCA test results...... 15 7. Ischnura gemina locations 2011/2012...... 16 8. Percent cover of aquatic transects for I. gemina sites...... 20 9. Percent cover of upland transects for I. gemina sites...... 21 10. Percent cover of aquatic transects for/, denticollis sites...... 22 11. Percent cover of upland transects for I. denticollis sites...... 23 12. Comparison of aquatic transects for sites with I. gemina and I. denticollis...... 24 13. Comparison of upland transects for sites with 1. gemina and I. denticollis...... 25 14. Percentage of sites with I. gemina 1985 --2012...... 27 15. Mean county maximum temperature 1970 -- 2012 ...... 38

viii LIST OF APPENDICES

Appendices Page

1. Prescence/Absence of Ischnura gemina...... 51 2. Water Chemistry Values...... 57 3. Representative Photos of sites with I. gemina and I. denticollis...... 61 1

INTRODUCTION

Species of the order Odonata (dragonflies and damselflies) are aquatic insects, dependent on wetland habitats for their lifecycle. Eggs are generally inserted into vegetation in or near water or into water itself, and naiads are aquatic until metamorphosing into flying adults. As adults, odonates usually remain near wetlands, foraging for food. The loss of wetlands globally, and specifically in California, is well documented (see for example Tiner, 1984; Goals Project, 1999; Burkett and Kusler, 2000). Although legal protection is stronger than in the past, wetlands continue to be threatened by habitat alteration, water diversions, and polluted runoff. Climate change may lead to additional stresses on wetlands and the species using them. Although specific details of climate models differ, sea level rise, changing precipitation patterns, and higher temperatures are anticipated with climate change. These changes are likely to affect wetlands in several ways. Sea level rise is anticipated to inundate coastal lagoons, affecting salinity and potential salt water intrusion into inland streams and wetlands. Warmer air temperatures may lead to warmer water temperatures and changes in water chemistry. In addition, changes in precipitation patterns may affect the volume, timing, and extent of freshwater runoff into wetlands, affecting water depth and persistence, biogeochemistry, and vegetation patterns (see for example: Titus, et. al, 1991; Burkett and Kusler, 2000; Parry, et. al, 2007; Chomesky, et. al, 2015). Whether, and to what extent, that new climate conditions and patterns will affect species may be species and location specific. Some species may have a large tolerance for changing conditions (or some areas may be limited in the effects of climate change), while other species will likely have to adapt to new conditions or migrate to more appropriate conditions for long-term survival. Species with small ranges, low mobility, and narrow habitat requirements w ill probably face more severe constraints than more generalist, widespread species (Gibbons, et. al, 2002). One such species is the San Francisco forktail damselfly (Ischnura gemina), a wetland species endemic to the San Francisco Bay area. Ischnura gemina is considered to be “one of the rarest odonates in the United States”, and is classified by the International Union for Conservation of Nature (IUCN) as “vulnerable” with “decreasing” populations (Abbott, 2007). The species is found in discrete populations in freshwater wetlands (Garrison and Hafemik, 1980; Garrison and 2

Hafemik, 1981; Hannon and Hafemik, 2007). Its habitat appears to be limited to “small, mostly open seepages, ponds, or canals in the coastal region of the San Francisco Bay Area” with emergent vegetation in which females lay eggs (Garrison and Hafemik, 1980, pg. 91). Habitat assessments (Hafemik 1991 and Hafemik unpub. data) also note that the development of dense vegetation, especially dense stands of Typha, is a threat to the persistence of the species at various sites. Although a petition for listing I. gemina as endangered was submitted in 1991, the U.S. Fish and Wildlife Service has not yet listed the species. The range of a closely related species, Ischnura denticollis (black-fronted damselfly) overlaps that of I. gemina in the San Francisco Bay area, but is more widely distributed overall. Ischnura denticollis ranges from Kansas to Texas, west throughout California, and south through Mexico to Guatemala (Manolis, 2003; Odonata Central, 2015). Visually, the two species look identical; they are distinguished by differences in male claspers and by differences on the female prothorax (Kennedy, 1917). In 1917, Kennedy (1917) identified a sympatric population of I. gemina and I. denticollis at Sharon Pond, Santa Clara County. Surveys in the 1980s and 1990s also documented sympatric populations (Leong and Hafemik, 1992). Surveys between the 1980s and 1990s documented a decline in the number of I. gemina populations. Habitat loss was attributable to only a small number of extirpations. Research also documented hybridization between the two species (Leong and Hafemik, 1992; Tiemey, 1996), which may be threatening I. gemina populations. Projections of climate change also indicate a likely threat to the species. Sa'nchez-Guille'n et. al (2014) predicted an initial expansion of potential habitat, followed by a reduction in suitable habitat for I. gemina, due to climate change, along with an increased risk of its extinction. They also predicted a reduction in overlapping ranges between I. gemina and I. denticollis.

Distribution of_Ischnura gemina Ischnura gemina was originally described in 1917 based on four individuals from Sharon Pond, near Stanford University, and from Coyote Creek in San Jose; both sites are in Santa Clara County (Kennedy, 1917). The species remained unknown for the following 60 years until it was rediscovered in the late 1970s in five sites in Marin, San Francisco, and San Mateo Counties (Garrison & Hafemik, 1980). Four additional populations were discovered between 1982 3

andl984 in San Mateo County (Hafemik, unpub. data). During the same time period, a search of museum records documented/, gemina from collections dated between 1897 and 1969. Specimens had been collected in Marin, San Francisco, San Mateo, Alameda, Santa Cruz, and Monterey Counties (Garrison and Hafemik, 1981; Hafemik, unpub. data). See Figures 1 and 2 and Appendix' 1 for distribution. Growing interest in the species as potentially endangered led to extensive field surveys between 1985 and 1997, documenting/, gemina in a total of 46 locations. These surveys confirmed additional I. gemina populations in Sonoma and Solano Counties, documenting the species in nine counties in the overall San Francisco Bay area (Appendix 1, Figure 2) (Hafemik, 1988; Hafemik, unpub. data).

San Francisco f ls ALAMFDA 1919 SAM H 1897 m m '

1919

Figure 1: Historic distribution of Figure 2: Distribution of I. I. gemina from museum records gemina 1979 - 1997

The survey data documented cycles of local extirpation and recolonization of I. gemina in some sites, as well as local extinction of I. gemina from other sites (Hafemik, unpub. data). Surveys in 1985 documented the loss of habitat for I. gemina through development at one site in 4

San Francisco County (site 15) where the species had been documented in 1978/1979. (See Appendix 1 and Figure 3 for site locations.) Two additional sites (sites 30 and 41, in San Mateo and Santa Clara Counties, respectively), were converted from natural to channelized streams, with concrete substrate and banks. Although water remained in the channel, the highly modified sites supported no aquatic vegetation and this was a likely cause of the extirpation of I. gemina. By 1997, an additional site (site 17, San Mateo County) had been developed, resulting in the loss of wetlands and I. gemina habitat (Hafemik, unpub. data). Between 1986 and 1992, Ischnura gemina was extirpated from five sites (sites 17, 18, 20, 33 in San Mateo County and site 44 in Santa Clara County) due to lack of water. Although a marsh was present near site 20, no I. gemina were detected there. During surveys in 1996/1997, sites 17, 18, and 33 were surveyed again. Field notes from these surveys (Hafemik, unpub. data) indicate a lack of suitable habitat for site 17, and no I. gemina in site 18, potentially due to insufficient water and/or dense vegetation. Ischnura gemina was present at site 33 in 1996, but was not documented in 1997. Site 28 (San Mateo County), which supported I. gemina in the 1980s was found to be dry in 1996. Overall, comparison of the data from the 1980s and 1990s shows a loss of I. gemina populations. However, not all sites were monitored each year, and no comprehensive survey has been completed since 1980. For a subset of 25 sites surveyed in 1990 - 1993,1, gemina were confirmed in 10 sites (40 percent), including areas in Alameda, Marin, and San Mateo Counties, and four sites not previously surveyed in Sonoma County. By 1996/1997, surveys of 13 sites found I. gemina in only five sites (38.5 percent) in Alameda and San Mateo Counties. In 1997, /. gemina was not present in one site where it had been documented in 1996. (See Appendix 1 for summary of surveys locations by date.) The surveys from the 1980s and 1990s also documented sympatric populations of I. gemina and I. denticollis in 10 sites, although the number of sites and locations varied across years (Appendix 1; Leong and Hafemik, 1992; Hafemik, unpub. data). Sympatric populations were documented in Alameda, San Mateo, and Santa Clara Counties. Over time, three of these sites (sites 1, 4 and 39, Alameda and Santa Clara Counties) converted to populations of only I. denticollis (Appendix 1; Hafemik, unpub. data). One additional site (site 2, Alameda County) converted from sympatric populations to I. denticollis in 1990, and again had sympatric 5

populations in 1996. By the mid 19|90s, several sites also supported hybrids of I. gemina and I. denticollis (sites 3, 4 and site 51, Alameda and Santa Clara Counties, respectively). Since comprehensive surveys have not been completed since 1980, updated surveys would provide more current data on the species’ range.

Site*#?** ■ MT-S

' VS ■'lit 10 " <' Sue 37 4»: Site 51 ||Site C. » 4 JX .Site 20 i m * * Sue 29 y S.te 28

•* . «. Site 17 '«Jfeite25

Site 4 h

Legend: Solid markers: Sites re-surveyed in 2011 Open circles: Sites not accessible or no habitat in 2011 Data M BARI MOAA. U.S. Navy, NCA, GEBCO

Figure 3: Survey locations for Ischnura gemina (1980s - 1990s surveys and 2011) 6

Habitat Characteristics Beyond the general preference for open water with emergent vegetation (Garrison and Hafemik 1980), little detailed information is known about the habitat requirements of I. gemina. Given the limited range of the species, extirpation of some populations from sites with seemingly suitable habitat, and the potential for significant changes in habitat features with land use changes and anticipated climate change, more detailed information on the species’ habitat preferences is needed. Such information can help inform conservation practices, potential reintroduction and habitat restoration efforts, and adaptive management and maintenance practices of wetlands with existing populations of I. gemina. Vegetation structure and diversity are important factors influencing the presence of odonate species (Gibbons, et. al, 2002; Homung and Rice, 2003; Ward and Mill, 2005). Vegetation plays a key role in several aspects of odonate biology and the availability of plant species and/or structure may be important to the persistence of odonates at a site. Submerged vegetation is important for females to oviposit, while above water vegetation and upslope vegetation are important features for resting, foraging, and mating. Other habitat characteristics, including patch size, temperature, substrate, and water chemistry may be important in suitability of a wetland for odonate species, and changes in these characteristics from climate change could affect viability of species such as I. gemina at a site. Since odonate naiads are aquatic until emergence into winged adults, salinity and water temperature specifically may affect their growth and development. Studies of other freshwater invertebrates show varying tolerances for salinity levels (Dunlop, et. al, 2008). Experiments on several species of Ephemoptera and Diptera show changed growth rates, differences in time of emergence, and varying mortality rates with varying salinity (Hassell, et. al, 2006). In testing salinity tolerance of odonate species in Australia and Africa, Kefford et. al (2005) found many species were tolerant of saline waters, with high variability among species. However, for Ischnura heterostica, Kefford, et. al (2006) determined that salinity levels affected the growth rate of individuals, leading to a threshold where individuals died in salinities around 25 ppt. Surprisingly, the species grew faster at mid range salinities than at lower salinity levels. No previous research has examined the salinity tolerance of I. gemina. 7

This study reports on a comprehensive survey for I. gemina throughout its known range and evaluates various habitat variables to determine whether specific environmental characteristics affect site suitability for the species. The research seeks to answer the following questions: 1) Does I. gemina persist throughout its historic range in the San Francisco Bay Area? 2) Has the area of sympatry between I. gemina and I. denticollis changed since the 1990s? 3) Is the presence of I. gemina affected by water chemistry and vegetation structure? 4) What is the likelihood that I. gemina will persist with climate change? Based on available data for I. gemina, I expected a decline in the number of populations from the 1990s. I also anticipated a correlation between presence of I. gemina and vegetation structure and water chemistry.

METHODS Population Surveys To determine presence of I. gemina, I completed field surveys at wetland sites throughout the historic range of the species, beginning with a comprehensive survey of sites known to have supported/, gemina between 1980 and 1997 (Hafemik, unpub. data; see Figure 3 and Appendix 1). I conducted surveys between May and September, the prime flight season for I. gemina, on warm days with clear weather, and with low to moderate winds to the extent possible. Generally, I conducted surveys between 10:00 am and 15:00 pm daylight savings time. On warm, sunny days with high odonate activity, I slightly extended the end time of surveys. The time of day for the surveys was designed to maximize the likelihood of detection. Adults are most active during high sun, on warm, non-windy days, and activity in I. gemina slows by mid-afternoon (Hafemik, pers. comm., 2011). Survey methods must address two issues: the potential for false-negatives, where a species is present in a site but not detected, and the need for consistent survey methods across sites varying in size and habitat type. Le Due et. al (1992) state that in any survey, the uniformity of sampling effort is of great importance. The likelihood of detecting a species in a particular site is often a function of sampling effort: both the length of time of a survey and the number of survey visits. Lack of detection of a species does not necessarily equate to absence of the species from a site (Tyre et. al, 2003; Gu and Swihart, 2004; MacKenzie, et. al, 2006). The probability of detection is a function of population size, rarity of a species, variation in site-specific abundance of a species, whether a species is cryptic or highly visible, sampling effort, and presence or lack of suitable habitat (Gu and Swihart, 2004; MacKenzie et. al, 2006). Since determining occurrence of a species at a site is dependent on the detection probability of a species, replication of surveys is important to increase the detection probability and reduce the likelihood of false negatives. Replication can be achieved either through temporal replication (resurveying sites within a given season) or geographic replication (surveying multiple subsites within a site) (MacKenzie, et. al, 2006; Connor, pers. comm., 2011). Odonate researchers have used survey frequencies ranging from two to five surveys per site per season (see for example, Gibbons, et. al, 2002; Suhonen et. al, 2010; Homung and Pacas, 2006). In their study of presence-absence of three coenagrionid species (the same family as Ischnura), Gibbons et. al (2002) determined that three visits to each site lowered the probability of a Type II error (false negative), and resulted in detection rates “approaching 100%”. Further, in modeling the effect of false negatives in population surveys, Tyre et. al (2003) recommend three repeated visits to a site as the minimum needed to reduce the likelihood of false negatives. MacKenzie et. al (2006) indicate that under ideal conditions (no limits on resources for surveying) two surveys at each site is optimal, with a detection probability of 90 percent and an occupancy rate of 90 percent. A mark and recapture study on I. gemina documented a recapture rate of 73 percent, with an 81 percent to 90 percent recapture rate for males (Garrison and Hafemik, 1981). If present at a site, Garrison and Hafemik found the species was easily detected on one visit, as the species tended to show high site fidelity. In addition to the number of site visits, survey time can influence survey results. Review of past research on odonate surveys identifies a variety of methods and levels of effort for surveys, including many papers that do not specifically discuss methodology of sampling. Gibbons et. al (2002) used an average of 45 minutes per site for collection of three uncommon coenagrionid species (range 1 0 -9 0 minutes). In surveying for the locally threatened species, Ischnura pumilio, Allen et. al (2010) surveyed areas for 30 minutes to search exclusively for the targeted species, within a broader time frame for a broader survey. Other researchers did not define a set time for a survey, but attempted to collect all individuals possible (for example, see Stephens and Smith, 1999; Oerlti, et. al, 2000; Preston, et. al, 2004; Homung and Pacas, 2006; Leigh, no date;) Protocols ranged from walking the shoreline of a wetland “haphazardly” (Homung and Rice, 9

2003) to defining points or transects for sampling (for example, Samway and Steytler, 1996; Stephens and Smith, 1999; Suhonen et. al, 2010). Most of these studies focused on determining the diversity of odonates at a site, rather than confirmation of presence of a particular species. I based my survey protocols on the above examples. For each site, I completed two to three surveys, usually by sampling multiple areas of a site, once during the season, on the same day. For sites too small to sample different distinct areas, I surveyed two to three times on different days during the season. For sites that were large enough to sample two areas, but not three, on one day, I surveyed two areas, but did not necessarily return on a subsequent date for a third sample. For a given site, I spaced sample locations far enough apart to reduce the potential for capturing the same individuals. Ischnura gemina is not a wide disperser, and daily movement averages less than seven meters (Garrison and Hafemik, 1981; Hannon and Hafemik, 2007). Instead of defining a precise distance between sample points at a given site, I targeted survey points to areas with appropriate habitat characteristics for I. gemina (open water with some emergent vegetation), but located each sample point to ensure they were at least seven meters apart. Within each site, I based survey points on: a) access to the site and feasible access to water edge; b) presence of open water with emergent vegetation; c) where possible, an attempt to sample different habitat structures within the same site. For example, a number of sites have high habitat heterogeneity, and included small standing pools with emergent vegetation as well as stream channels. I located survey points to try and incorporate the variety of habitats within each site; d) distribution of sample points throughout the wetland. At each survey point, I collected as many Ischnura damselflies as possible using a standard aerial net during a 30-minute survey period. About halfway through the 2011 field season, I reduced the time of the survey to 20 minutes at sites where I observed no odonates (of any species) during that time. Prior to that adjustment, there was no case where I saw damselflies only in the last 10 minutes of a survey. By the 2012 season, I was able to identify one Ischnura species (/. cervula) without capture, and modified my methods to omit collection of individuals that I could easily identify without collection. 10

I focused collection efforts on adult males, as these are more easily observed than females; however, I did not exclude collection of females and included them in my sample as they occurred. To ensure that the same individuals were not repeatedly captured, I kept all collected individuals temporarily stored in glassine envelopes and identified all specimens at the end of the survey time, releasing each individual after species identification. Risk of mortality is low for individuals kept in glassine envelopes for up to two hours (Hafemik, pers. comm., 2011). Where identification in the field was unclear, I either retained the specimen or took digital photographs of the male appendages or the thoracic region of females for species confirmation in the laboratory. At each sample area, I walked slowly along the edge of the water and corresponding lengths of upland habitat. Rather than setting a defined linear extent for surveys, I based distance covered on accessibility and presence/absence of damselflies. Where concentrations of damselflies were high, I focused efforts on capturing individuals to obtain a good sample number. Where I saw few or no damselflies, I extended the distance of the survey to cover a larger region of the sample area. In all cases, I walked the survey length a minimum of three times. During the summer of 2011,1 surveyed all accessible locations of /. gemina, based on data from the 1980s and 1990s surveys (Figure 3). I was unable to survey 15 of the sites previously surveyed due to lack of remaining habitat, or lack of access to the site. Access to sites was precluded either due either to altered site conditions or lack of permission to access the site. I also excluded the Salinas River in Monterey County (site 46). This site was not surveyed during the 1980s/1990s surveys, and local experts have not found I. gemina present there. For purposes of presence/absence of a species, I considered a site positive if I documented any individual of that specific species in any of the sample areas for that site. Because I found I. gemina at only two sites in 2011, both in the more northern historic range of the species (northern San Francisco County and Marin County), I conducted additional surveys for the species in 2012, focusing my efforts on surveying coastal and near coastal sites in Marin and Sonoma Counties (Figure 4). I chose this focus to determine whether the species now occurred north of its historic range. I chose sites initially by searching for wetland areas using Google maps, road maps, and the knowledge of local naturalists. 11

In 2012\, I also surveyed one site from the 1980s/1990s surveys wheije I did not have access in 2011, and I included sites on the Presidio in San Francisco where I. gemina had been detected in 2007 (Moore and Hafemik, 2007). I also re-surveyed the sites where I found I. gemina in 2011. For surveys in 2012,1 completed surveys using the protocols for the 2011 season as defined above.

Habitat Chamctenstics At each sample location during summer 2011,1 collected the following environmental variables: cloud cover, air temperature, water temperature, pH, salinity, type of stream/pond substrate, and qualitatively identified water flow (still, slow, moderate, fast). Early in 2011,1 began collecting data on water clarity using a secchi disk, but the water level in many of the sites was too shallow for an accurate measurement, so I omitted these data from surveys. For pH, I used an Oakton pH 2 Tester, calibrated to a three-point scale before each field day. At each sample location, I submerged the meter and took a reading when the meter reading had stabilized. I recorded the value on a data sheet, and rinsed the meter with distilled water after each use to avoid contamination at the next location. At the end of each field day, I checked the calibration of the meter to ensure the meter did not drift from its calibrated values. I measured salinity using a standard refractometer. For measurement of water and air temperature, I used a standard mercury thermometer. After recording air temperature, I submerged the thermometer at the point where I took pH and salinity measurements, and recorded the value after the thermometer measurement stabilized. I used results from field data to determine whether site characteristics differed between sites with and without I. gemina. I compared values of the environmental variables for sample locations with presence of I. gemina to values for sites with I. denticollis. I also compared sites with I. gemina to sites with other coenagrionids (excluding sites with I. gemina or I. denticollis), and to sites with no Zygoptera. No sample included both I. gemina and I. denticollis. Because all sites with Ischnura species also included either I. gemina or I. denticollis, I did not specifically compare sites with I. gemina to sites with other ischnuran species. Most sites with other coenagrionid species also had I. perparva or I. cervula. 12

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Fond 1 Site DR

Muddy Hollow Five Brooks Kent Lake Wildcat Lake : Coastal Trail Lakes" .Phoenix lake Corte Madera Bolinas 5

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Rodeo Lake Dragonfly Creek Sut to Baths McLarenlRarkf 'jft. McLaren Park

Legend: Solid markers: Sites re-surveyed in 2011 Open circles: Sites not accessible or no habitat in 2011

Figure 4: Additional survey locations for Ischnura gemina 2012

For my statistical analysis, I used Welch’s two sample t-test, run in Program R (R Core Team, 2013), to test significance in mean values of environmental variables between sites with and without I. gemina and an F-test to test for differences in the variances of environmental 13

variables. All variables except ^alinity were normally distributed, and after log transformation, salinity was approximately normal. I estimated percent cover of vegetation over a 60-meter distance of each sample site. I used a 0.5 X 0.5 meter quadrat to estimate vegetation in one-meter square blocks at 1 meter, 20 meters, 40 meters, and 60 meters points, from the water edge into the water (A “aquatic quadrats”), and from the water edge upland for two meters (B, C “upland quadrats”) on Figure 5). I began the meter tape at one end of the survey transects. If damselflies were found in only one small stretch of the transect length, I ensured that the tape measure included that area, but placed the tape at random to cover that section. Several sites were not long enough to include the 60-meter quadrats or wide enough to include the C quadrats. During 2012 surveys, to complete as many additional surveys as possible, I collected data on habitat characteristics only for sites with I. gemina.

Figure 5: Schematic of Vegetation Transects Squares represent 0.5 X 0.5 meter quadrate

In the field, I estimated percent cover for the following classifications: unvegetated (includes open water and mud for aquatic transects and bare ground, duff, rocks, tree stumps, and concrete for upland transects); rushes (includes rushes, sedges, and cattails); floating vegetation (unrooted vegetation, includes duckweed, algal mats, floating scum); grasses (terrestrial), dead vegetation, and other (includes vines, shrubs, woody vegetation). I used a binomial generalized linear mixed effects model in Program R to determine what variable(s) produced the best model predicting the presence of either I. gemina or I. denticollis. To build models, I removed all samples with missing data for the covariates, but included 14

samples with either species not detected. For each species, I defined site as the random effect, and then built models by starting with a single environmental variable and adding additional environmental variables. I used AIC values to select best fit models. To reduce the number of vegetation variables (n=14), I used principle components analysis. To determine which components to include in habitat models, I used a combination of the proportion of variance and the cumulative proportion of each variable (Holland, 2015). The proportion of variance for each component does not differ widely, and does not give a clear cutoff for the number of components influencing variation. The first four components each explain from 18—11 percent of the variance, with the remaining components each adding 9 percent or less (Figure 6). The first four components represent only 54 percent of the cumulative proportion of variance. Because each of the next components add only a small amount to the cumulative variance, I chose to use only components one through four in my models.

■ Percent of Variance ■Cumulative Percent

Figure 6: PC A test results 15

RESULTS Population Surveys In my 2011/2012 surveys, I found I. gemina in six of the 71 sites (8.5 percent) that I surveyed including four sites where I. gemina was previously documented (Site 8, Marin County; Site 26, San Mateo County; Site 50, Sonoma County; and Fort Point, San Francisco County) (Figure 7). The other two sites with I gemina were close to Site 8 (DR, KB, Marin County). Ischnura gemina was absent from the other 35 sites I surveyed where it had been documented in

Figure 7: Ischnura gemina locations 2011/2012 16

prior years. I also found no I. gemina in any of the 36 additional sites 1 surveyed in Marin and Sonoma Counties in 2012, sites outside of the prior surveys. Although water was present in three of the four sites that were dry in prior surveys (sites 18, 20, San Mateo County, and site 44, Santa Clara County), I. gemina was not present in any of these sites in 2011. Site 44, however, supported a population of I. denticollis. This site had not been monitored since 1988 (when it was dry), but had supported populations of both species in 1986. In addition, the type locality of I. gemina (Sharon Pond, Santa Clara County; site 41), formerly noted as lacking suitable habitat due to concreting of the pond, had a fresh water stream flowing into the concreted pool, providing potential habitat for the species. However, I found no I. gemina at the site. I found I. denticollis in 13 of the 41 sites (31.7 percent), an increase from 18 percent of sites in the 1980s/1990s (Appendix 1). Locations included sites in Alameda, Solano, Marin, Sonoma, San Francisco, San Mateo, and Santa Clara Counties. I found both I. gemina and I. denticollis present in only one site (Site 50, Sonoma County), although each species was found in different sample locations within the site. I found no sympatric populations in the same seimple area. (See Appendix 1 for full species identification of each site.) Twenty-one sites (51.2 percent) supported other species of Ischnura and another 19 sites (46.3 percent) supported other coenagrionid species. All sites with/, gemina or I. denticollis also supported other ischnuran or coenagrionid species.

Habitat Characteristics Water flow and site substrate Both I. gemina and I. denticollis were found primarily in sites with muddy and/or silty substrates, and with still or slight water flows. Several sites with I. denticollis had substrates with sand or a cobble and silt mix, and several sites had moderate water flows. Similarly, sites with other Ischnura species had predominately mud/silt substrates, although two sites had sandy or rocky substrates. Water flow was mostly still, with three sites having moderate flows. For sites with other coenagrionids, patterns are similar: most sites have mud/silt substrates with three sites comprised of rocky sand or rocky mud. Table 1 summarizes the characteristics by group of species. For all categories of groups, mud/silt is the most common substrate type, and slow or still water flows are dominant. 17

Table 1: Water Flow and Site Substrate Characteristics Ischnura Ischnura All All No All gemina denticollis Ischnura coenagrionidae coenagrionidae sample points Substrate Mud/silt 100% 96% 94% 86% 74% 86% Sand 0% 0% 2% 2% 3% 2% Rocky 0% 4% 4% 11% 18% 8.3% Cobble 0% 0% 0% 0% 5% 2% W ater flow 0% 13% 13% 33% 13% 20% Moderate Slow 11% 9% 6% 14% 65% 22% Still 89% 78% 81% 53% 39% 59%

Site Chemistry: temperature, salinity, pH Data on water chemistry for surveys prior to 2011 are not available. For surveys in 2011- 2012,1, gemina was present in salinities ranging from 0 ppt to 2 ppt, with water temperatures ranging from 1 5 -2 4 degrees Celsius (Table 2, Appendix 2). Ischnura denticollis was present in salinities ranging from 0 ppt to 10 ppt, with one additional sample location having salinity at 20

Table 2: Water Chemistry Values Air temperature Water Salinity range pH range; (°C) range; temperature (°C) (ppt); average average average range; average I. gemina 10-31 1 5 -2 4 0 - 2 7.3-9.1 19.3 19.2 0.5 8.0 n=15 n=15 n=15 n=4 I. denticollis 17-35+ 1 8 -3 2 0 -1 0 * 6.9-8.8 27.0 23.5 2.1 8.0 n=24 n=24 n=24 n=20 All 16 -3 3 1 5 -2 7 0 - 6 7.0-9.1 coenagrionid 22.3 20.5 0.8 7.6 speciesA n=28 n=30 n=9 n=30 No zygoptera 1 5 -4 6 13-31 0 - 4 2 6.8 -9.0 species 25.2 21.8 5.9+ 7.8 n=65 n=65 n=68 n=43 * one outlier of 20 ppt omitted from average + one outlier of 42 ppt omitted from average A omits samples with I. gemina and I. denticollis 18

ppt. Water temperature for I. denticollis ranged from 18 to 32 degrees Celsius. Based on limited data (n = 4), I. gemina was present in sites with pH ranging from 7.3 to 9.1, while I. denticollis was present in sites with pH ranging from 6.9 to 8.8 (n = 20). For sites with I. gemina compared to sites with I. denticollis, mean air temperature, water temperature, and salinity are statistically significant based on t-tests (p=0.005, p=0.006, p=0.014, respectively). There is no difference between mean pH values (p=0.96) (Table 3). Similar trends are evident when comparing sites with I. gemina to sites with other coenagrionids (excluding sites with I. gemina and I. denticollis) and sites with no Zygoptera. For air temperature, water temperature, and salinity, mean values for sites with I. gemina are lower than sites without I. gemina. For pH, the mean value is higher for sites with I. gemina (Table 2, Appendix 2). Similarly, mean values for sites with I. gemina and for sites without I. gemina are significantly different for air temperature, water temperature, and salinity (Table 3; Appendix 2).

Table 3: Significance for means of site chemistry

Air temperature Water temperature Salinity pH I. gemina vs. I. p=0.005 p=0.006 p=0.014 p=0.69 denticollis I. gemina vs. p=0.044 p=7.363e-06 p=0.042 p=0.69 coenagrionid I. gemina vs. no p=0.002 P=0.01 p=2.931e-06 p=0.56 zygoptera

While the mean values of the environmental variables are significantly different among sites, the variances of most of the variables does not differ between sites with I. gemina and sites with I. denticollis (Table 4). Only the variance of salinity is significantly different across all group comparisons. 19

Vegetation Ischnura zemina Sites with I. gemina ranged from large pools of open water with emergent vegetation and/or rushes/sedges/cattails, to sites with narrow channels covered in dense vegetation surrounding small pockets of open water. (See Methods section for definition of vegetation categories). (See Appendix 2 for representative photos.) Vegetation characteristics also varied within sites, among sample points.

Table 4: F-test values for site chemistry values I. gemina and I. denticollis Water Temperature Air Temperature Salinity pH Calculated F value 0.7597 0.98451 0.019029 3.1006 p value 0.5883 0.9664 2.80e-10 0.1025 df (num, denom) 15, 25 9,19 15, 15 3,19 I. gemina and other coenagrionid Calculated F value 0.4168 0.9145 0.0305 0.7268 p value 0.157 0.8932 4.86e-15 0.6175 df (num, denom) 10, 19 14, 32 15, 43 10, 19 I. gemina and no zygoptera Water Temperature Air Temperature Salinity PH Calculated F value 0.5178 0.6605 0.0305 0.7268 p value 0.157 0.8932 1.316e-15 0.6175 df (num, denom) 15,64 14, 62 15,66 15, 14

On average, vegetation composition in aquatic transects (quadrats A, see Figure 5) was 53 percent unvegetated, 28 percent herbaceous vegetation, and 16 percent rushes/sedges/cattails, with high site-specific variability. Sites were predominately a mix of unvegetated space and herbaceous vegetation (n=5). One site was an almost even mix of unvegetated space and floating vegetation. Three sites also supported rushes/sedges/cattails, with one site having close to 50 percent cover of these species. Figure 8 shows the dominant vegetation cover of the aquatic transects for sites with I. gemina. Two sites (KB and 50, Marin and Sonoma Counties) were dominated by a mix of water and aquatic vegetation along my transects, with no clear edge to upland vegetation; for these sites, I included quadrats B and C with data for the quadrat A. Adding these quadrats had little change on the percent cover for aquatic transects, with only site 50 changing in dominance from open water to emergent vegetation. 20

Figure 8: Percent Cover of aquatic transects for I. gemina sites * * values <5 percent omitted

Looking at upland vegetation (transects B, C), sites had rushes/sedges/cattails, herbaceous vegetation, or ground as the dominant categories (Figure 9). All sites supported some extent of rushes/sedges/cattails. On average, sites were comprised of 25 percent rushes/sedges/cattails, 21 percent herbaceous vegetation, and 34 percent unvegetated ground. Other vegetation includes grasses and some dead vegetation. The presence of rushes/sedges/cattails in some upland transects is due to these species growing close to the water edge, but beyond the definition of my “aquatic” transects (see Methods). In other cases, my sampling occurred during low tides, when aquatic species are present in the “upland” transects. Although sparse in most sites, vegetation in upland transects shows more diversity in the number and types of species than water transects. Channel banks ranged from mild to steep slopes leading to the water edge. 21

h 100.00 ,------

90.00 ------

Figure 9: Percent Cover of upland transects for I. gemina sites* * values <5 percent omitted

Ischnura denticollis Sites with I. denticollis (n=14) also had varied features and characteristics across sites and within a site (see Appendix 2 for representative photos). Many of the sites had defined channels with upland banks. However, pools of water with fringing vegetation, similar to sites with I. gemina, were present at several locations. Most aquatic quadrats were dominated by open water with floating or herbaceous vegetation. Floating vegetation comprised over 30 percent cover in two sites and rushes/sedges/cattails were present in five sites. The extent of rushes/sedges/cattails is lower than at sites with I. gemina. Sites show a wider range of vegetation categories than sites with I. gemina. Figure 10 shows the dominant vegetation cover of the aquatic transects for sites with I. denticollis. On average, across sites, percent cover consisted of 62 percent unvegetated 22

space (open water, mud, or bare ground), 18 percent herbaqeous vegetation, 11 percent floating vegetation, and 3 percent rushes/sedges/cattails.

10000 S it e 90 00 ■ 10

80 00 m 14 mi6 7000 □ 19 bb2 Q 50 00

40.00 r

30.00

20.00

10.00

000

Figure 10: Percent Cover of aquatic transects for/, denticollis sites * * omits values < 5 percent

The upland quadrats of sites with I. denticollis show a mix of mostly unvegetated ground mixed with herbaceous vegetation and grasses (Figure 10). Similar to the upland transects for sites with I. gemina, several sites supported rushes, sedges, and cattails in the upland transects. On average, sites had 7 percent rushes/sedges/cattails, 18 percent herbaceous vegetation, 20 percent grasses, and 35 percent unvegetated ground. Comparing aquatic transects between sites with I. gemina and sites with /. denticollis (Figure 12), the sites have similar vegetation types, although percent cover and the detailed vegetation communities differ. While both I. gemina and I. denticollis sites have a mix of open 23

water/mjud and aquatic vegetation, sites with I. denticollis show morej diverse species vegetation than sites with/, gemina.

Figure 11: Percent Cover of upland transects for I. denticollis sites * * omits values < 5 percent

Approximately 43 percent of sites with I. gemina (n=3) support rushes/sedges/cattails, while approximately 36 percent of sites with I. denticollis (n=5) support these vegetation types. For floating vegetation, one site with I. gemina (approximately 17 percent) and approximately 71 percent of sites with I. denticollis (n=10) support this category of vegetation. Other aquatic vegetation (emergent and submerged) is found in 5 sites with I. gemina (approximately 83 percent of sites) and in 11 sites with I. denticollis (approximately 79 percent of sites). Herbaceous vegetation is found in five of six (83 percent) sites supporting I. gemina, and most sites with / denticollis (n=12, 85 percent). 24

Comparing ijpland transects for sites with I. gemina and I. denticollis (Figure 13), sites with I. denticollis show similar vegetation categories, although specific species and vegetation communities are more diverse in sites with I. denticollis than sites with I. gemina. Sites with /. gemina are characterized primarily with a mix of rushes/sedges/cattails, herbaceous vegetation, and bare ground. Sites with I. denticollis show more herbaceous vegetation and grasses, with some sites having rushes/sedges/cattails. Two I. denticollis sites had a high extent of rushes and marsh vegetation: my surveys of these sites coincided with low tides. Rushes/sedges/cattails are present in many of the sites, as they are able to grow beyond the aquatic transects.

100.00

90.00

80.00

70.00 Legend 60.00 1. gemina • 1 desiUcoliis 50.00

40.00

30.00

20.00

10.00

0.00

Figure 12: Comparison of aquatic transects for sites with/, gemina and /. denticollis* * omits values < 5 percent

Habitat Modeling Based on AIC values, the best fit model for predicting presence of I. gemina includes water temperature, air temperature, and pH (AIC = 55.9). However, eight other models resulted in AIC 25

values within two points (uj) to AIC = 57.9). These additional models include a range of other variables not in the best fit model (e.g., cloud cover, different vegetation components), and different combinations of multiple variables. For predicting presence of I. denticollis, the best fit model includes air temperature, water temperature, pH, salinity, vegetation component 1 and vegetation component 3 (AIC = 156.1). Two other models are close to an AIC value of delta 2 (158.5), each using the above variables and either vegetation component 1 or vegetation component 3. Vegetation component 1 is positively correlated with rushes, dead vegetation, and unvegetated areas, all within aquatic transects (loadings 0.506, 0.470, and 0.466, respectively). Component 3 is positively correlated with both aquatic and terrestrial unvegetated area (loadings of 0.548 and 0.435, respectively).

Figure 13: Comparison of upland transects for sites with I. gemina and I. denticollis* * omits values < 5 percent 26

DISCUSSION Population Status and Trends The number of populations of Ischnura gemina has declined by 92 percent from the 1980s to 2011/2012 (Figure 14). The pattern of loss shows a contraction of I. gemina’s range to northern, mostly coastal locations (see Figure 7). Ischnura gemina has not been documented in the southernmost counties of its historic range (Monterey or Santa Cruz Counties) since 1946. Populations in Santa Clara County, the county just north of Santa Cruz County, also are extirpated from formerly known sites. In addition, the species appears to be extirpated from the eastern region of its historic range in Contra Costa, Alameda, and Solano Counties. Currently, all known populations of I. gemina are present in San Mateo, San Francisco, Marin, and Sonoma

Counties, all within the northern range of the species’ historic distribution. Five of the six extant populations of I. gemina are found along the Pacific Ocean or San Francisco Bay. Site 50 (Sonoma County) is an outlier in terms of I. gemina presence at coastal wetlands. However, this 27

site is not a recent change in the species’ distribution, as I. gemina was first detected in Sonoma County in 1991. Based on surveys in 2012 at wetlands near, and north of, the known I. gemina sites, I. gemina does not appear to have migrated north or expanded into additional areas (see Figure 4). Such northward expansion has been documented in other species due to changing temperatures attributed to climate change (for example, see Paremsan, et. al, 1999; Hickling, et. al, 2005; Wellenreuther, et. al, 2011). Therefore, I. gemina appears to have contracted in range, rather than migrated or colonized new locations. This range contraction is ultimately consistent with model predications by Sa'nchez -Guille'n, et. al (2014), although their predictions note an initial increase in suitable habitat for I. gemina by 2020, with a range contraction by 2080. Ischnura denticollis, however, has expanded its range into sites previously occupied only by I. gemina. This species is now found in eight sites previously known to support I. gemina and is present at an additional five sites that formerly supported sympatric populations with I. gemina but where I. gemina is no longer present. This suggests that I. denticollis has a relative advantage over I. gemina. Sa'nchez-Guille'n et. al (2014) predict a range contraction for I. denticollis by 2020, concentrating in the north and west areas from a current larger range. The increase in populations of I. denticollis in my surveys does not necessarily contradict Sa'nchez-Guille'n et. a/’s prediction. Ischnura denticollis has a much broader distribution than the region I surveyed, and this study did not survey its entire range. Therefore, no assessment can be made regarding predictions of its distribution. However, it is clear that I. denticollis has expanded its range in the San Francisco Bay area given the conversion of sites from sites with I. gemina only to sites supporting I. denticollis.

Potential Causes o f Species Decline Habitat Loss and Modification Loss of habitat is a common, and perhaps the most common, cause of species’ declines. Wetland loss is often caused by development of a site, or draining or filling of wetlands for other purposes. For I. gemina, this direct habitat loss is a minor cause of the decline of the species’ populations. Only two sites (sites 15, 17 in San Francisco and San Mateo Counties, respectively), representing approximately 4 percent of all sites supporting the species in the 1980s/1990s, have 28

been destroyed. Another two sites (sites 17 and 41, in Sain Mateo and Santa Clara Counties, respectively) supporting I. gemina were modified between the 1980s and 1990s, from natural streams to concreted channels. The modification of the sites and loss of aquatic vegetation likely led to the loss of I. gemina populations, representing an additional 4 percent of the cause of the species’ decline. Therefore, the dramatic decline of I. gemina is not primarily due to habitat loss. Annual fluctuations in water availability also affect the persistence of I. gemina populations. Years with localized, temporary dry conditions in some of the wetlands result in the extirpation of the species (and other odonates) from those sites. Although overall precipitation patterns and water runoff are key to maintaining standing water in wetlands, the extent of precipitation alone does not account for the localized dryness of some wetlands. In some cases, /. gemina is absent from one wetland that is dry while a second geographically close wetland supports (Appendix 1; Hafemik, unpub. data). Groundwater flows, soil type, land management activities, or some other factor likely influences the site-specific presence of water in at least some of the smaller wetlands. Regardless, this temporary loss of habitat led to the extirpation of I. gemina in 11 percent (5 of 46) of sites during the 1980s and 1990s, although the number of dry sites varied by year (Hafemik, unpublished data; see Appendix 1). In 2011/2012,I. gemina was extirpated from two sites (4.8 percent of sites) due to local dry conditions. Data indicates that the species can recolonize a site after an absence of one or more years (Appendix 1). However, such recolonization is limited by the flight ability of a species, and hence the distance between habitat patches. As I. gemina populations decline and are geographically further apart, the possibility of recolonization decreases. In spite of the few sites permanently converted from wetland habitat or periodic localized dry conditions, wetlands persist in most of the 2011/2012 sites surveyed that previously supported I. gemina. Over 50 percent of these remaining wetlands (21 sites) support other species of Ischnura, with I. denticollis, the species closely related to I. gemina and known to have sympatric populations with/, gemina, present in 32 percent of those wetlands (12 sites). The absence of I. gemina at the remaining wetlands may be due to one of several reasons, or a combination of causes: a) Sites are further from surviving populations than the flight distance of I. gemina, preventing recolonization by the species when a population is lost at one site. This increasing 29

distaijce between populations could have occurred during over the 1980s and 1990s, leading to a point where very few I. gemina populations were present, and were too far apart to recolonize former sites. b) Ischnura denticollis has some advantage over I. gemina, allowing I. denticollis to outcompete I. gemina. This study did not attempt to assess this possible outcome. c) Specific habitat characteristics at the remaining wetlands preclude /. gemina, or favor I. denticollis and/or other odonate species. Vegetation Presence and Structure Many factors influence a wetland and the suite of species present: vegetation types, water chemistry, and geomorphology all affect specific wetland features and characteristics, and in turn, the fauna species present. For example, habitat characteristics in a tidal wetland differ from those in a freshwater marsh or a riparian stream channel, and at least some species may be more limited to one type of habitat over the other. Various processes can also influence or modify a habitat over time. Vegetation communities may be affected by an invasive species, land management practices may alter water flows or vegetation, and adjacent or upstream development may affect sedimentation in a stream or pond. Active wetland restoration, a much-desired goal in many areas, may alter a site from one wetland type to another, again affecting composition of the flora and fauna. Therefore, even though a “wetland” may persist, specific characteristics of that wetland may favor or deter particular species. The presence or absence of I. gemina may be affected by subtle or specific characteristic of sites. Vegetation presence, type, and structure may play an important role in the presence or absence of species from a site. Multiple odonate researchers note the importance of specific habitat features to different assemblages of odonates. Such features may include vegetation composition, structural diversity, emergent vegetation for oviposition and perching, and vegetation structure up to 20 meters from the water edge, used for shelter or perching (see for example, Johnson, 1996; Schindler et. al, 2003; Carchini et. al, 2007; Allen et. al, 2010). The extent to which vegetation composition has affected the presence of I. gemina is unclear. Data from the 1980s/l990s surveys provide limited information on vegetation characteristics at sites with I. gemina. Field notes and photos from these early surveys of sites supporting I. gemina generally indicate a dominance of open water, typically in channels or broad 30

marsh plains, wjith minimal, low emergent vegetation (see Appendix 2 for representative photos). When present in sites more heavily vegetated with aquatic vegetation, I. gemina was found in areas with openings in vegetation, indicating a preference for more open areas (Hafemik, unpub. field notes). Comparing photographs of sites from the 1980s/l 990s to those from 2011/2012, it is clear that vegetation at most sites is substantially more developed and denser in 2011/2012, although substantial amounts of open water remain in most sites (see Appendix 2 for representative photos of sites). However, since detailed data on vegetation species and percent cover is not available prior to 2011, direct analysis of vegetation changes and potential effect on the presence of I. gemina cannot be made. Percent cover data for 2011/2012 indicate that both I. gemina and I. denticollis are present in sites with a mix of open water and aquatic vegetation. The average extent of open water is similar for sites with/, gemina (47 percent) and for sites with / denticollis (57 percent). This difference is unlikely to be biologically significant relative to the presence or absence of the two species. Although sites with Z denticollis show a wider range of conditions, Z denticollis is also present at sites with conditions similar to sites with Z gemina, even though the latter species is not present. Therefore, the relative percent cover of open water and emergent vegetation alone are not the critical features for presence of Z gemina. The presence of Z gemina at sites with more developed vegetation does not necessarily indicate the long-term persistence of the species. Hafemik and Smyth (1993) note that “... Z gemina ... show strong preferences for more open habitat, and are virtually never found in areas clogged with Scirpus and Typha” (pg. 5). Furthermore, dominance of “Typha may lead to extirpation of Z gemina due to loss of sun-exposed water and banks” (Hafemik, unpub. survey notes). Other research supports the concern about Typha or other dense, tall vegetation threatening the presence of specialized odonate species. In their study of odonates, Maybry and Dettnam (2010) found a negative relationship between odonate species richness and presence of reed canary grass and Typha species, resulting in more generalist species in sites with these plants. Although their research focused on odonates in prairie pot-hole habitats, and included analyzing vegetation effects on a wide assemblage of odonates, their study supports the concern about the loss of more specialized species, like Z gemina, in sites with invasive Typha species. 31

These researchers noted the resulting loss of submerged and floating vegetation and restricted flight movement with increasing presence of the canary grass and Typha. Therefore, the decline of open water and more prevalent and/or dense vegetation in 2011/2012 may constitute a threat to the continued persistence of I. gemina. The average percent cover of rushes/sedges/cattails at sites with I. gemina was higher than sites with I. denticollis (32 percent vs. 9 percent, respectively, Figure 12), which seems to contradict prior findings that I. gemina require low emergent vegetation and minimal sedges or Typha. Of the six sites supporting I. gemina in 2011/2012, three had populations of rushes/sedges/cattails ranging from 15 percent to 46 percent cover. Rushes, sedges, and cattails tend to grow quickly, potentially leading to loss of open water and declining habitat for 50 percent of the extant populations of I. gemina. The 46 percent cover in one of the sites in particular raises concern about the habitat quality and the potential for I. gemina to persist at that site. Given the low number of sites with I. gemina, the presence of rushes/sedges/cattails at several of these sites may simply be within a normal range of variability of a small sample size. However, the presence of those species may also indicate a threat to the long-term viability of the habitat for I. gemina. The open pools of water present at these sites may only be sufficient in the short-term to support the species. Continued growth and expansion of rushes/sedges/cattails or rushes could cause further decline in the quality and quantity of suitable habitat for I. gemina. If this is the case, the findings from prior research related to loss of I. gemina with presence of Typha or sedges would be supported. Given the few remaining populations of 1. gemina, monitoring and some site management, prior to the loss of I. gemina at sites, is warranted to prevent extinction of the species. Given that female I. gemina use aquatic vegetation to lay eggs and to rest, the presence of floating vegetation may be a critical factor in assessing whether sites provide suitable habitat for I. gemina. Ward and Mill (2005) found that use of areas by the damselfly Calopteryx splendens may be a function of oviposition site preference. In their study, Carchini et. al (2007) noted the importance of macrophytes for oviposition by coenagrionid species, and Johnson (1996) found that the extent of emergent vegetation and type of oviposition materials contributed to the suitability of a site for damselflies. The use of floating vegetation does not necessarily preclude the use of other vegetation (rushes, sedges, other rooted aquatic vegetation), but it may provide a 32

preferred substrate. Both sites with I. gemina and /. denticollis show presence of floating and other aquatic vegetation (Figure 12). For sites with/, gemina, the average value for floating and other aquatic vegetation is 49 percent. For sites with I. denticollis, the average value is 28 percent. Although the overall average is higher in sites with /. gemina, a number of sites with /. denticollis support floating and other aquatic vegetation in similar percentages to some of the sites with I. gemina. This general trend holds even looking only at floating vegetation, and omitting the category of other aquatic vegetation. It appears that sites without I. gemina populations, but where I. denticollis is present, have adequate floating vegetation to support either of the species. Further, the lack of /. gemina at sites with lower percentages of floating vegetation does not necessarily indicate that as a cause of the species’ absence. One site in Marin County (KB) supporting /. gemina is surprising in that the site was dominated by aquatic vegetation (97 percent cover) with no large areas of open water. The presence of /. gemina in this site runs counter to the habitat characteristics previously described for the species (Garrison and Hafemik, 1980) and is distinguished from other sites with /. gemina in 2011/2012 by the lack of open water. Extirpation of /. gemina has been noted at sites where aquatic vegetation dominates the water area, particularly at site 13 (San Francisco County) (Hannon and Hafemik, 2007). Those authors suggested that extensive aquatic vegetation filling the channel where I. gemina had been found earlier led to the extirpation of the species in the 1990s. After clearing the channel and reintroduction of I. gemina to the site, vegetation again filled the channel, resulting again in the loss of the species from the site. The extent and long-term viability of a population of /. gemina at KB is unclear, as only one teneral individual was found. However, the presence of a teneral individual suggests at least a breeding pair of I. gemina, if not a local breeding population. Although intriguing, the characteristics of one site, with one individual, is insufficient to draw broad conclusions about habitat preferences or suitability for I. gemina. It may be that the species can indeed persist in sites with dense, low stature vegetation, as opposed to sites with denser stands of rushes, sedges, or cattails. More likely, the presence of one individual does not indicate that the site will continue to sustain a population of /. gemina. If this is the case, this population may be at risk of extirpation. However, KB is also a relatively large site and access to the site beyond the outer edges was difficult. Additional surveys may have documented a larger number of individuals. 33

Overall, though, based on presence of rushes/sedges/cattails at three sites and including site KB, 66 percent of known I. gemina populations may be at risk of extirpation due to vegetation characteristics. More recently, sedges and cattails have been expanding at a fourth site (Fort Point, Presidio, personal observation), further raising the risk to I. gemina populations and the species long-term viability there. Characteristics of upland vegetation, important for perching and foraging habitat, also shows no unique characteristics between sites with I. gemina and I. denticollis although sites with I. denticollis have a more diverse range of vegetation types. The upland characteristics are unlikely to influence site suitability between I. gemina and I. denticollis. The best-fit habitat model predicting presence of I. gemina does not include any type of vegetation as a component. Thus, the best fit model does not necessarily indicate a good fit - it is merely the model with the lowest AIC score with the variables modeled. Based on other research on odonates (see for example, Hafernik, 1991; Johnson, 1996; Schindler et. al, 2003; Carchini et. al, 2007; Allen et. al, 2010; Maybry and Dettnam,), vegetation type and extent may well be an important factor in site suitability for/, gemina. Water Flow and Substrate The similarity of substrate type and water flow for sites with and without I. gemina indicates that these variables are likely not a major factor in defining habitat differences among the sites 1 surveyed for I. gemina and I. denticollis, or I. gemina and other species. Substrate type and water flow characteristics for sites surveyed are similar, regardless of the particular coenagrionids present or absent, and are predominately mud/silt substrate with still or slow water flows (Table 1). The low variation across sites, however, is not surprising, as survey sites for 2011 (the year data on substrate and water flow was collected) were defined as sites known to have supported I. gemina previously. The presence of I. gemina in only still or slow water confirms prior knowledge that the species prefers still or calm water (Hafernik and Garrison, 1986; Hafernik, pers. comm., 2011). Habitat models also support the low importance of substrate in determining site suitability for I. gemina versus I. denticollis: models incorporating substrate show no improved prediction for either species than models without substrate. Therefore, it is likely that factors other than site substrate and/or water flow affected the presence or local extirpation I. gemina. 34

Site Chemistry: temperature, salinity, and pH The results of this research suggest that I. gemina is more restricted in its range of habitat than the closely related I. denticollis or other coenagrionid species. In general, I. gemina persists in sites with cooler air and water temperatures, and in a more limited range of salinity (0-2 ppt) than I. denticollis or other coenagrionids(see Tables 3 and 4). Habitat models support the likelihood that air and water temperature are important variables for determining the presence of I. gemina. The inclusion of these variables in the best-fit model (and models with similar ratings), supports the field data results that temperature is a significant variable in sites with I. gemina compared to sites without, although the model cannot be used to determine any specific relationship between species and variables. Given that I. gemina is present only at sites with salinity between 0 and 2 ppt, and that salinity values are statistically significant for sites with and without I. gemina, salinity may be a highly restricting factor for site suitability for the species. Ischnura denticollis and other coenagrionids are present in salinities up to 10 ppt, a much broader range than for I. gemina. It is unclear whether pH is an important contributor to site suitability for I. gemina. Although the best fit model for predicting I. gemina incorporates pH, field results show no difference in mean pH values or variance for sites with and without I. gemina. Although data indicate that pH is not likely a critical factor affecting presence or absence of I. gemina, pH values were calculated on few data points. More data over time would be needed to determine whether or not this parameter is a critical factor in the presence of I. gemina or for any comparison between tolerance ranges for I. gemina and I. denticollis. Other variables not present in the best fit model for I. gemina may also be useful in assessing what site characteristics are important or detrimental to the species persistence. Mazerolle (no date) notes that relying only on the “best fit” model may not be an adequate model to predict presence of a species and recommends determining the delta AIC values (AIC value for model - minimum AIC value) to determine a relative strength of each model, with delta AIC less than 2 generally showing strong evidence for the model. For I. gemina, seven models have a delta AIC value of 2 or less. All models include pH and most include water temperature. However, different models are also comprised of different variables. For example, some models within the 2- point AIC range incorporate salinity and different components of vegetation. The 35

relatively small difference between models with a delta AIC of 2 or less indicates that other variables may also be important in predictive modeling for presence of/, gemina. For instance, from field data, salinity appears to be a factor in site suitability for I. gemina, even though it is not included in the “best fit” model. For predicting the presence of / denticollis, the best fit model uses pH, salinity, water temperature, air temperature, vegetation component 1 and vegetation component 2. Only two models fall within a delta AIC of 2 or less. These models include the same variables with either vegetation component 1 or vegetation component 2. Vegetation component 1 correlates positively with rushes, dead vegetation, and unvegetated area all in the aquatic transects. Vegetation component 2 correlates positively with unvegetated areas in both aquatic and upland transects. Since data on environmental variables are not available for surveys prior to 2011, it is unknown whether the conditions at sites surveyed in 2011 are similar or different than conditions in the 1980s and 1990s, or whether any changes in environmental variables or vegetation may have affected the loss of I. gemina in sites which supported the species in earlier decades.

Sympatric Populations and Interspecific Hybridization Sympatric populations, of Z gemina and Z denticollis, first documented in 1917 (Kennedy), have persisted over multiple years. Results from surveys in 2011/2012 indicate that most of the previously reported sympatric populations have converted to populations of Z denticollis, without the presence of I. gemina (see Appendix 1). In 2011, one site (Site 50, Sonoma County) supported both species, although at different sample locations. During the 1990s, this site supported I. gemina, with no records for I. denticollis. The cause of this species conversion is not clear and this study could not assess the full range of possible causes. Specific habitat data (vegetation, water chemistry, substrate, and water flow) are not available for earlier surveys, so whether / gemina was affected by changes in site conditions is unknown. Since I. denticollis has a broad geographic range, the species probably colonized the site irrespective of presence of absence of I. gemina. Some unknown event (e.g., drought year or poor reproductive year for I. gemina) may have led to the loss of the species at this site. Without a nearby population within flight distance, the species may not have been able to recolonize the site. Currently, no source population is known nearby for I. gemina to recolonize. 36

Hybridization between I. denticollis and I. gemina may have led to the decline of I. gemina in some sites. Leong and Hafemik (1992) documented hybrids at some sites, although morphologically pure individuals of I. gemina were also present. In 1996/1997, hybrids were also documented (Hafemik, unpub. data; Appendix 1). Moore (2007) found that some individuals characterized morphologically as I. denticollis contained I. gemina alleles while individuals morphologically identified as I. gemina showed no I. denticollis alleles, although genetic testing found some “undetermined” individuals among/, gemina specimens. Moore concluded that hybridization between the two species may be occurring more than is suggested by morphology, and that I. denticollis may be able to outcompete I. gemina. Sa'nchez-Guille'n et. al (2014) further assessed the effect of hybridization between/, gemina and I. denticollis, and found the potential for loss of Z gemina due to hybridization between the two species. Individuals showing I. denticollis morphology, and classified as /. denticollis in my study, may in fact be introgressed hybrids, with some I. gemina genes. Genetic testing would be needed to verify whether individuals are pure I. denticollis or a hybrid. Regardless of the retention or not of /. gemina genes, hybridization may result in the loss of I. gemina as a species.

Species Persistence under Future Climate Conditions Climate change, and the generally accepted corresponding changes in temperature, precipitation patterns, freshwater runoff patterns, and sea level rise (see for example, Knowles and Cayan, 2002; Helmuth et. al, 2005) and their effect on flora and fauna are an increasing concern among biologists. Recent research has shown a number of changes related to increasing temperatures and climate change, including: a) shifts in the geographical ranges of species across various taxa; b) changes in phenology, breeding, and other behaviors of species; c) mis-matched timing between predator and prey availability; and d) changes in species composition (see for example, Walther, et. al, 2002; Veteli, et. al, 2002; Wilson, et. al, 2005; Logan, et. al, 2006). Sa'nchez-Guille'n et. al (2014) predict range contraction for/, gemina (andI. denticollis) under climate change models. Based on results from 2011/2012 surveys, the contraction for I. gemina is already occurring at a more accelerated rate than predicted, although the extent that 37

climate change per se is driving that contraction is unclear. However, given the apparently more restricted habitat requirements of I. gemina, climate change could affect habitats and site suitability for I. gemina through increasing temperatures, changes in precipitation patterns, sea level rise and salt water intrusion. Appropriate air temperature is important to many insects, and influences their development and survival. Air temperature also affects water temperature, especially in shallow pools and streams, and in the upper strata of deeper water bodies where immature odonates live. Warmer air temperatures under climate change will affect water temperatures, at least in shallow pools and the upper water strata where odonates are typically found. Data for site conditions from the 2011/2012 surveys show a corresponding increase in water temperature with increases in air temperature. The restricted water temperature range in which I. gemina is found suggests that the species will be particularly vulnerable to increasing temperatures, and the species may face further extirpation if waters warm too much. With so few populations of I. gemina remaining, any further loss of a populations significantly increases the risk of extinction of the species. Broader trends also support the finding that I. gemina is currently present in the cooler regions of its historic range. Three of the four counties still supporting I. gemina (Marin, San Francisco, and San Mateo) have lower mean annual maximum temperatures (1970 - 2012) than counties no longer supporting I. gemina (Figure 13, PRISM, 2004). Mean annual maximum temperature in Sonoma County, the fourth county supporting I. gemina, falls within the mid­ range of values for all counties. Since Sonoma County spans across a wide east-west and north- south range, an overall higher county-wide temperature than the smaller Marin, San Francisco, and San Mateo Counties is not unexpected. In contrast, I. denticollis persists in all counties, with a wide range of temperatures. These temperature data and the distribution of I. gemina further supports the concept that I. gemina is more restricted to cooler areas than I. denticollis or other zygoptera. 38

Count)'

“ • * A lam eda ^ Contra Costa — Marin ■"'*#"» Sonoma *H|H*San Francisco “"♦"San Mateo “ '**■“ Santa Clara Solano "•*— Santa Crux '""•"",K M onterey

Figure 15: Mean County Maximum Temperature 1970 - 2012

Similarly, potential changes in freshwater and salinity concentrations anticipated under climate change could put further pressure on I. gemina’’s populations. As noted, the species is present in a very narrow range of salinity (0-2 ppt), and potential changes in salinity under climate change could threaten its populations. Although sites with I. gemina present in 2011/2012 are not directly connected to ocean waters, rising sea level has the potential long-term to affect the pocket wetlands fringing the San Francisco Bay, where I. gemina persists. Knowles (2010) notes “an increase in the rate of rise of mean sea level is one of the primary and potentially most troublesome aspects of projected climate change”. He also notes that sea water inundation is a concern throughout the San Francisco Bay Area, and models predict a shift in salinity 10 to 15 kilometers inland with a 100 cm rise in sea level. Rising sea level could result in the direct loss of coastal wetlands, through complete inundation of low elevation wetlands, and/or could lead to increases in salinity of wetlands. Since most of the current populations of/, gemina, and the historic range of the species, are coastal wetlands fringing the San Francisco Bay, a rise in sea 39

level could result in freshwater wetlands becoming increasingly saline and less suitable for I. gemina. Increases in sea level may especially affect I. gemina populations in Marin County (Abbott’s Lagoon, site 8), which appears to be the strongest remaining population of the species, and at Fort Point (San Francisco County). These sites are both close to the shoreline, and are vulnerable to sea level rise and salt water intrusion. While a broad sandy berm separates the site from tidal or ocean waters at Abbotts Lagoon, increasing storm surges and increased sea level could overtop the berm or rise to completely inundate the site. Fort Point, a small freshwater seep at the base of a bluff adjacent to San Francisco Bay, is also at risk of being inundated with increasing sea level. Large storms already overtop the road adjacent to the site. Increases in the magnitude and frequency of storms, also an anticipated outcome with climate change (Scavia, et. al, 2002), would increase the potential of coastal freshwater wetlands becoming more saline. To better understand whether I. gemina has a broader tolerance to warmer waters and/or more saline waters than current data suggest, research on oviposition occurrence and the surv ival of eggs and naiads is needed in varying temperatures and salinities. The effects of climate change may not only directly affect mortality of individuals or populations. Changes in environmental conditions also could have sublethal effects that reduce the health and viability of individuals. Climate change might cause changes in behavior, particularly of aquatic invertebrates; effects on growth and metabolism; changes in fecundity; and/or changes in availability of food (Sweeney, et. al, 1990, Masters, et. al, 1998; Sweeney, et. al, 1990; Helmuth, et. al, 2005; Kefford, 2006), which over the long-term could affect the ability of a species to live and successfully reproduce. For aquatic species, increasing water temperature affects levels of dissolved oxygen, a critical element for aquatic species, and other complex chemical processes are also influenced by temperature. Furthermore, the interaction of water temperature, salinity, and pH, and possibly other water chemistry variables such as dissolved oxygen, probably is more important than any single variable in leading to conditions suitable at a particular site for I. gemina or other species. 40

Conclusions and Recommendations

The long-term viability of I. gemina is clearly at risk. The species has declined dramatically in the past several decades, while the population of /. denticollis has increased. Further, while sympatric populations no longer occur, hybridization between I. gemina and I. denticollis has occurred. The need for immediate and ongoing efforts to conserve /. gemina is clear. The long-term survival of /. gemina depends on continued viability of the present populations and expansion in the number of sites supporting it. Without a minimum number of suitable habitat patches, appropriate patch arrangement, and adequate immigration and colonization, a species faces increased risk of extinction (Maschinski, 2006). In the past, populations of I gemina likely functioned as meta-populations, and persisted in spite of high local extinction rates, due to a sufficient number of discrete populations to immigrate and colonize sites (Hafemik, 1991). Today, the distance between sites supporting I. gemina is generally beyond the known range of the species’ typical flight distances. Should one of the few remaining populations be lost, it is unlikely that /. gemina from another population will recolonize the site. Given the prior pattern of local extinction of the species, further loss of populations is probable, and extirpation at even one site represents a large percent of the overall population. For the remaining I. gemina populations, successful reproduction at any given site is critical to maintaining each population. However, with the exception of Abbott’s Lagoon in Marin County, the remaining populations do not appear to support large numbers of individuals. At most sites, only one or a few individual I. gemina were detected, which raises questions about minimum viable population sizes and reproductive success. Regardless of the population size, any population is at risk of extirpation in the event a stochastic event. A decline in the quality of habitat, whether through vegetation changes, temperature increases, or drought, also increases the risk of extinction. These factors limit the likelihood of ongoing persistence of the species. While species frequently evolve or otherwise adapt to new conditions, such as the effects of climate change, as /. gemina likely has in the past, evolution occurs over a long period of time, over many generations, and populations of I. gemina probably will not have sufficient time to thrive in the new conditions. Accommodation to change can also involve the migration of species to areas with more suitable conditions, which is contingent on a species’ ability to disperse and 41

the presence of suitable habitat patches to which they can disperse. As noted, the dispersal ability of I. gemina is limited and to date, no migration of the species is evident. In addition, developed landscapes, common within the species’ range, hinder the movement of species across it to colonize new locations (Walther, et. al, 2002). Walther et. al (2002) note that species with low adaptability and/or low dispersal capacity, like I. gemina, living in a fragmented landscape are expected to experience increased extinction rates. Finally, the specific habitat requirements of the species appear to be more restricted than for other species. The tolerance of the species for varying conditions is not know, and should be assessed to better understand the risks to I. gemina from changing climate conditions. In the short-term, conservation efforts should include the reintroduction or introduction of I. gemina to additional sites, increasing the number and distribution of discrete populations. Long­ term monitoring and management of sites will be needed to ensure suitable habitat for the species. Habitat areas for the species will need to be managed to ensure open waters, sunny banks, and presence of emergent vegetation without other vegetation becoming too dominant, at least until a better understanding of the range of conditions suitable for I. gemina are better understood. The Presidio in San Francisco supports several potential reintroduction areas for I. gemina. The Presidio Trust, the federal agency managing the Presidio, has undertaken extensive habitat restoration in the park. The Trust has considered reintroduction of I. gemina to a recently restored wetland along the east arm of Mountain Lake. Revegetation of the area was designed based on a possible reintroduction, emphasizing aquatic vegetation and open water. The typical willow species often used in wetland restoration projects are not being considered for this site to avoid over-shading of water. Small wetland pools have also been created at El Polin springs. These pools support aquatic vegetation, suitable for I. gemina. However, aquatic vegetation in several of the smaller pools has become increasingly dense over the years, limiting the extent of open water and degrading habitat for I. gemina (personal observation). Ongoing vegetation management will be needed to ensure these sites do not become overgrown with dense aquatic vegetation or upland species. One benefit of implementing a reintroduction plan on the Presidio is the long-term and extensive habitat restoration volunteer program dedicated to ongoing restoration and maintenance of native habitat areas in the park. 42

The existing I. gemina population at Fort Point, also within the Presidio, could provide a source population for the introduction of I. gemina at El Polin springs and at the east arm of Mountain Lake. Although close to El Polin, Fort Point is likely too far for I. gemina to immigrate frequently enough to establish a population in the near future. The population at Fort Point itself is at risk. Typha is currently encroaching into the channel at Fort Point (personal observation), and should be removed before it becomes too extensive and degrades the habitat. Currently, the extent of Typha is small, and should be relatively easy to remove without extensi ve damage to the existing population of I. gemina, but if left unmanaged, the site may soon become too degraded to support the species. The past reintroduction project of I. gemina at Glen Canyon in San Francisco (Site 13) (Hannon and Hafemik, 2007) shows the feasibility of reintroduction again at this site. However, extensive vegetation removal would be necessary to remove overhanging willow, and ongoing management would be needed to maintain the site. The San Francisco Parks and Recreation Department, which manages this site, lacks the resources to commit to long-term active management of sites. This limits the feasibility of reintroduction of I. gemina. Establishing a volunteer program to steward the site may be feasible should restoration and reintroduction be undertaken. Public opinion and public support are also needed for a successful program. The visual quality of a site managed for I. gemina may, or may not be, supported by local residents and site visitors. Other potential reintroduction sites are the flood control channels, particularly in San Mateo County where I. gemina was previously found. Flood control channels typically need regular maintenance to remove aquatic vegetation and maintain channel capacity for water flows. Although Hafemik (1991; and unpub. data field notes ) notes a threat to I. gemina populations through the cleaning and alteration of flood control channels, maintenance of channels to maintain flood waters, and minimum vegetation, is not necessarily incompatible with conservation of I. gemina populations. Clearing channels of large, woody vegetation could maintain open water habitat and low stature emergent vegetation for I. gemina, while providing needed flood control management. To protect I. gemina, phasing the clearing over multiple years, is critical. Phased clearing of a site over a couple years would allow refugia areas for I. gemina eggs and naiads, allowing the population to sustain itself. Removal of all vegetation over 43

one year, even if done outside of the adult flight and mating season, could easily destroy eggs and naiads overwintering in the channel. This phasing and maintenance of habitat areas at sites is particularly important since recolonization of a site by a nearby source population is unlikely. Protected lands, such as the Presidio or county parks, provide the best opportunity for introduction of I. gemina, as they typically are at reduced risk of development and may have the resources to maintain sites for the species. Surveys of potential introduction sites could be completed in Marin and Sonoma Counties. Abbott’s Lagoon at Point Reyes in Marin County (Site 8) supports the strongest population of I. gemina, based on number of individuals collected during 2011/2012 surveys. The site is managed by the National Park Service (NPS), and is protected as a natural area, providing long-term habitat for I. gemina. NPS should conduct an analysis of potential impacts from rising sea level to better determine the risks to the site from seawater inundation. This information is needed to inform future management of the site. NPS should also complete regular monitoring of the site for I. gemina to detect any early indications of population decline or loss, and monitor for vegetation changes to the site. If species such as Typha emerge, immediate actions should be taken to remove the vegetation before it spreads. Reintroductions of the species and site management will not guarantee the long-term viability of the species. Reintroduction of species can be difficult, and sites frequently are not managed in perpetuity, even with an initial commitment to manage an area. Sites must be chosen based on knowledge of conditions conducive to the survival of I. gemina. At least some of the sites that formerly supported the species may now be unsuitable, due to vegetation or waters that may be too warm for the species. Further, reintroduction efforts will not preclude ongoing hybridization with I. denticollis, nor will they ensure appropriate habitat conditions with climate change. They are, however, an important interim measure to ensure the species does not go extinct. Increasing the number of populations and maintaining good habitat for the species is the best chance for its survival. To provide a buffer against periodic local extirpations, populations should be close enough to ensure immigration and recolonization between sites. Without actions taken soon to conserve the species, the outlook for I. gemina is poor. Additional research into the tolerance of I. gemina to increasing temperatures and salinity changes is also important. The long-term conservation of I. gemina may depend on how well it can tolerate conditions under climate change, and/or ongoing active management of the species to 44

establish new populations at new sites as conditions change. A better understanding of the effects of climate change on I. gemina and its range of tolerance to conditions will help inform conservation practices, including reintroduction locations and site management. Developing a region-wide conservation plan and partnerships between land managers may provide the best hope for maintaining adequate habitat and populations of I. gemina. While other damselfly species, including potentially other ischnurans, will likely persist in bay area wetlands, the loss of I. gemina would represent the loss of the only endemic species to this area. Beyond the general problem of species loss, the loss of the San Francisco forktail damselfly would reduce the rich biological heritage of the San Francisco Bay area. While the long-term survival of I. gemina can not be guaranteed, we should at least take action to try to preserve the species. 45

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Legend D: I. denticollis present; G: I. gemina present; M: I. denticollis and I. gemina present; H: hybrid present; 0: site surveyed; no /. gemina present; /: no habitat remaining; NA: not sampled. County abbreviations: Ala = Alameda; S.F = San Francisco, S.M. = San Mateo, Mont. = Monterey, Son. = Sonoma

Site City Co. Area < '78- ’80- ’85 ’86 ’87 ’88 ’89 ’90 ’91 ’92 ‘93- ’96 ’97 2011 1978 ’79 ’84 ’94 1 Fremont Ala Auto mall M MMMM D D NA prkwy 2 Hayward Ala Baumberg MMM D M MD Rd 3 Oakland Ala Oakland MM G, 0 airport H 4 Union Ala Jean St M M D, D City H 5 Berkeley Ala no site G NA specified 1914 6 Point Marin no site G NA Reyes specified 1969 7 Point Marin McClures G D Reyes Beach 8 Point Marin Abbotts G G Reyes Lagoon 9 Point Marin Drakes G 0 Reyes Estero 10 Point Marin Limnatour G D Reyes 11 Marin Marin Tennessee G G 0 Valley 12 San S.F. no site G NA Francisco specified 1910 13 San S.F. Glen Park G 0 0 0 0 Francisco Appendix 1 Presence/Absence of I. gemina, con’t.

Legend D: I. denticollis present; G: I. gemina present; M: I. denticollis and I. gemina present; H: hybrid present; 0: site surveyed; no /. gemina present; /: no habitat remaining; NA: not sampled. County abbreviations: Ala = Alameda; S.F = San Francisco, S.M. = San Mateo, Mont. = Monterey, Son. = Sonoma

Site City Co. Area < f78- ’80- ’85 ’86 ’87 ’88 ’89 ’90 ’91 ’92 ‘93- ’96 ’97 2011 1978 ’79 ’84 ’94 14 San S.F. Lake G D Francisco Merced 15 San S.F. Sansome G // Francisco St 16 Belmont S. Old Co. G G 0 0 D M. Rd 17 Belmont S. Quarry Rd G dry / dry M. 18 Brisbane S. Industrial G G G dry 0 0 M. Rd. 1982 19 Burlingame S. Carolan G 0 0 D M. channel 20 Burlingame S. David Rd G GG dry+ dry+ 0 M. 21 Burlingame S. 1744 G 0 dry M. Rollins 22 E. Palo S. nr golf G 0 Alto M. course 23 Palo Alto S. Dumbarton GGG G 0 M. Br. 24 Foster City S. Laurel G 0 M. Creek 25 Redwood S. Chemical GD City M. Wy 26 San Bruno S. WofSFO G GG GGG G M. Appendix 1 Presence/Absence of /. gemina con’t.

Legend D: I. denticollis present; G: I. gemina present; M: I. denticollis and I. gemina present; H: hybrid present; 0: site surveyed; no I. gemina present; /: no habitat remaining; NA: not sampled. County abbreviations: Ala = Alameda; S.F.= San Francisco, S.M. = San Mateo, Mont. = Monterey, Son. = Sonoma

Site City Co. Area < '78- ’80- ’85 ’86 ’87 ’88 ’89 ’90 ’91 ’92 ‘93- ’96 ’97 2011 1978 ’79 ’84 ’94 A San S. M. PG&E GG NA Bruno Substation B San S. M. Oyster G NA Bruno Point offramp C San S. M. San GG NA Bruno Bruno offramp 27 San S. M. Brittan G 0 0 Carlos Ave 28 San S. M. 19th Ave G G dry / Mateo 1984 29 San S. M. E 20th G G 0 Mateo 1984 30 S San S. M. Colma G/ NA Francisco Creek 31 S San S. M. Shaw G* G G NA Francisco Road nr 380/101 32 S San S. M. no G NA Francisco specific 1897 site 33 San S. M. Coyote Pt G G G dry G 0 0 Mateo 34 Redwood S.M. Marsh G 0 0 City Road exit Appendix 1 Presence/Absence of I. gemina, con’t.

Legend D: /. denticollis present; G: I. gemina present; M: I. denticollis and I. gemina present; H: hybrid present; 0: site surveyed; no /. gemina present; /: no habitat remaining; NA: not sampled. County abbreviations: Ala = Alameda; S.F = San Francisco, S.M. = San Mateo, Mont. = Monterey, Son. = Sonoma 00 Site City Co. Area < f78- ’80- ’85 ’86 ’87 00 ’89 ’90 ’91 ’92 ‘93- ’96 ’97 2011 1978 ’79 ’84 ’94 35 San S. M. Dore G G D Mateo Ave 1984 36 San S. M. no G NA Mateo specific 1902 site 37 Pacifica S. M. Sharp M M M 0 Park 38 S San S. M. no G NA Francisco specific 1915 site 39 Mt.View Santa Business M M M D 0 Clara Park 40 San Jose Santa Coyote G 0 Clara Creek 1915 41 Menlo Santa Sharon G / 0 Park Clara Pond 1914 42 Mt. View Santa Stevens MD Clara Creek 43 San Jose Santa Ross M NA Clara Creek 44 Alviso Santa Moffat M dry D Clara St. 51 Alviso Santa Moffat M, NA Clara Air H Field Appendix 1 Presence/Absence of I. gemina, con’t.

Legend D: I. denticollis present; G: I. gemina present; M: I. denticollis and I. gemina present; H: hybrid present; 0: site surveyed; no I. gemina present; /: no habitat remaining; NA: not sampled. County abbreviations: Ala = Alameda; S.F.= San Francisco, S.M. = San Mateo, Mont. = Monterey, Son. = Sonoma

Site City Co. Area < '78 ’80 ’8 ’8 ’8 ’8 ’8 ’9 ’9 ’9 ‘93 ’9 ’9 201 197 5 6 7 8 9 0 1 2 6 7 1 8 ’79 ’84 ’94 45 Santa Santa no G NA Cruz Cruz specific 191 site 9 46 Monterey Mont. Salinas G NA River 194 6 47 San S.M. San G 0 Carlos Mateo airport 48 Suisun Solan McCoy GD City 0 Creek 49 Cotati Son. Washoe G 0 Creek 50 Cotati Son. Gossage G M Creek 51 Livermor Ala. Los D NA e Posita Creek FP San S.F. Presidio G G Francisco Fort Point Pre San S.F. Presidio G s Francisco (multiple locations ) KB Pt. Reyes Marin Kehoe G 1 Bog Appendix 1 Presence/Absence of I. gemina, con’t.

Legend D: I. denticollis present; G: I. gemina present; M: I. denticollis and I. gemina present; H: hybrid present; 0: site surveyed; no I. gemina present; /: no habitat remaining; NA: not sampled. County abbreviations: Ala = Alameda; S.F = San Francisco, S.M. = San Mateo, Mont. = Monterey, Son. = Sonoma

Site City Co. Area < f78- ’80- ’85 ’86 ’87 00 00 ’89 ’90 ’91 ’92 ‘93- ’96 ’97 2011 1978 ’79 ’84 ’94 DR Pt. Reyes Marin Drainage G Pond McL San S.F. McClaren • D Francisco Park SB San S.F. Sutro D Francisco Baths + Original site dry; no I. gemina detected in adjacent wetland * I. gemina detected in two locations in 2007

Sources: Hafemik, unpub. data; Hafemik, 1993; Hafemik and Smyth, 1993; Moore and Hafemik, 2007. Appendix 2 Water Chemistry Values

Sites with L gemina compared to sites with /. denticollis

O TT

o CO «2 Ui o < CM

denticollis gemina

o C l O') E 0) to CM

o CM

in __ T denticollis gemma

o _ TT CM

— > JtSS C o _ 1 5 0 0 ir > —

o - T denticollis gemina Appendix 2 Water Chemistry Values, con’t.

Sites with I. gemina compared to sites with I. denticollis, con’t

Sites with /. gemina compared to sites with coenagrionid species, exlcuding I. denticollis 59

Appendix 2 Water Cjhemistry Values, con’t.

Sites with 7. gemina compared to sites with coenagrionid species, exlcuding 7. denticollis, con’t

o o a>

co

coenagrionid gemina

Sites with 7. gemina compared to sites with no zygoptera Appendix 2 Water Chemistry Vallues, con’t.

Sites with I. gemina compared to sites with no zygoptera san ativ e Ptiatos of sites with /. gemma and 1

2011 61 Appendix 3 Repress satire Photos of sites with I gtmina and L dsnticolUs, ocm’L

Representative photos of sites w ith hchnura gemina, c o n ’t Site 2<5: San Brano, nr Sam Francisco Airport, Sam M ateo County

1 gwm/jrsa documented us boik years.

She 4S. or Cotali Sonoma Covniy 1990

toON Appendix 3 Representative Photos of sites wilt/, gamins and L dmtimiMs, coa't. 63 Appendix 3 Representative Photos of sites with.I. gemina and £ dmticoilis, con’t.

Representative P t e s of sites with, neither Ischnura gmmm o r J. dvnSicoRis Site 22 East Palo Alio, San M ateo Comity Rodeo Lagoon. M arin County

lone 26, 2012 Aug 14,2011

Site 13^ San Francisco Site 34. San Male© Connsy ■ m m ■ m

Aug 13, 2011 M y 4,, 2011