Endangered Species Conservation & Management

Contributed Oral Presentations

Contributed paper sessions will be available on-demand for the duration of the conference, then again at the conclusion of the conference.


Nine Years of Indiana Bat Spring Migration Behavior
Piper L. Roby; Mark W. Gumbert; Michael J. Lacki
The endangered Indiana bat (Myotis sodalis) congregates in large hibernation groups in winter and travels after spring emergence to form summer maternity colonies, but information on migration behavior in this species remains limited to mostly band recovery observations. We tracked female Indiana bats in spring migration toward summer grounds using aerial radiotelemetry. Adult female Indiana bats were radiotagged in spring from 2009 through 2017, with 15 individuals successfully tracked to summer grounds and an additional 11 bats located in summer grounds via aerial telemetry after migration was complete. This resulted in the location of 17 previously unknown summer grounds for female Indiana bats, including adding Georgia, Alabama, and Mississippi to the summer maternity range. Two of the colonies identified in this study were south of the previously known southernmost colony in Tennessee, expanding the summer maternity range for the species by 178 km. Time-stamped location fixes along the migration path provided information about nightly and overall distances traveled, duration of travel, migration speed, and weather-related influences on bat behavior. Bats traveled 164.6 ± 26.2 km (±SE) on average from hibernacula to summer grounds and were migrating for an average of 7.3 ± 1.4 calendar nights. Bats alternated between foraging and traveling throughout each night of their migration route. Nightly migration rate was 9.9 ± 0.8 km/h and bats were active on the landscape for an average of 6.1 ± 0.4 h/night. Lower nighttime temperatures and lower barometric pressure correlated with use of layover areas during a migration night. Understanding bat behavior during migration can provide pertinent information for land managers to consider in efforts to conserve potential migration corridors, foraging areas, and roosting habitats of species in decline.
Gray Bat Activity Levels in Southwest Virginia
Hila Taylor; Megan Short; Karen E. Powers; William Orndorff; Richard J. Reynolds; William M. Ford
The endangered gray bat (Myotis grisescens) is a cave-obligate bat that forages along large river riparian corridors. In southwest Virginia, the species is showing some positive population growth trends and possibly a northward range expansion – perhaps due to ecological niche vacancy left by species affected by White-nose Syndrome such as the little brown bat (Myotis lucifugus). On occasion, gray bats will day-roost in bridges and culverts rather than caves during the maternity and migratory seasons. To better understand current gray bat distribution relative to landscape conditions, along with use of transportation structures in southwest Virginia, we continuously deployed 40 acoustic detectors throughout the upper Tennessee River basin and adjacent portions of the New River and Big Sandy River basins, April through November of 2019. Gray bats appeared initially near the Tennessee line following hibernation emergence and as the summer progressed, activity was present throughout much of the area, including into the adjacent New River and Big Sandy River basins outside their reported distributional range. Following volancy of pups and the cessation of maternity activity, further dispersal events and increases in activity were recorded. We observed infrequent, day-roost use of bridges and other anthropogenic structures particularly during fall migration. Because of the largely rural aspect of the studied landscape and numerous available caves, most environmental correlates to gray bat activity other than latitudinal*season interactions were equivocal. These data will assist managers, particularly those dealing with transportation structures to better define when and where gray bats could be present.
Habitat Selection and Home Range of Appalachian Cottontails in the Southern Appalachian Mountains
Corinne A. Diggins; Liesl Erb; J.J. Apadoca
Appalachian cottontails (Sylvilagus obscurus) are high-elevation lagomorphs that occur in the southern Appalachian Mountains of the eastern United States. This species is considered a federal Species of Concern and is listed as Knowledge-gap Species in North Carolina. Little information is known about home range of Appalachian cottontails since the few studies conducted on this species occurred in the northern part of their range. We conducted a regional study in western North Carolina in 2018-2020 to determine habitat and home range selection of radio-collared Appalachian cottontails. We trapped cottontails at 6 sites: 4 sites between 1,500-2,000 m, (hereafter ‘high-elevation’) and 2 sites between 980-1,220 m (hereafter ‘low-elevation’). Of the radio-collared cottontails we tracked, 20 cottontails (12 males, 8 females) had >30 points. We determined home range estimates at the 50% and 95% levels using minimum convex polygon (MCP) and biased-random bridges (BRB). We determined habitat selection using Euclidean distance-based analysis. The average MCP at the 50% and 95% home range was 0.80±0.13 ha (range: 0.21-2.16) and 3.4±0.75 (0.55-13.78), respectively. Average BRB at the 50% and 95% home range was 1.08±0.18 ha (range: 0.11-2.58) and 5.72±1.15 (0.83-19.44), respectively. There was no significant difference in home range size between the sexes or high- vs. low-elevation sites. At high-elevation sites, cottontails selected for shrub balds and heath balds more than expected based on their availability on the landscape. At low-elevation sites, cottontails used early successional habitat and pine forests more than expected. Our study highlights important information on the ecology of Appalachian cottontails that may guide management and conservation efforts in the future.
A Hitch on the Road to Recovery? Documentation of a Neuromuscular Disorder in Florida Panthers
Dave Onorato; Marc Criffield; Caitlin Kupar; Lara Cusack; Brian Kelly; Mark Lotz; Darrell Land; David Shindle; Mark Cunningham
Prospects for recovery of the endangered Florida panther (Puma concolor coryi) have improved since genetic rescue was implemented in 1995. However, threats to the population continue to emerge. In spring of 2018, the Florida Fish and Wildlife Conservation Commission (FWC) documented the presence of a neuromuscular disorder in panthers, termed feline leukomyelopathy (FLM), via video recorded by citizen scientists. In affected animals, FLM is associated with hindlimb incoordination and weakness. Increased monitoring, using video trail cameras and assisted by public reports, resulted in the documentation of additional cases in bobcats (Lynx rufus) and panthers. Cases of the disorder have been concentrated in southwest Florida; but it has also been documented >350km north, inferring FLM may be present statewide. Confirmation is only feasible via histological examination of the brain and spinal cord. FLM is characterized by degeneration of axons and myelin in the ventral and lateral tracts of the spinal cord with less severe lesions in the brain. More kittens have been shown to be affected than adults. Retrospective analyses indicate FLM was present as early as May 2017. Since 2017, there has been a total of 8 confirmed (2 panthers:6 bobcats) and 16 probable (11 panthers:5 bobcats) cases. While some causes have been ruled out (e.g., congenital, tick paralysis), a suite of biomedical tests have so far only provided negative or inconclusive results. Environmental toxins remain primary suspects. Testing continues on tissue samples collected opportunistically or via capture efforts. FWC has expanded its monitoring via deployment of video trail cameras, especially within public lands in core panther range where the presence of FLM has not been assessed. Although the impact of FLM on Florida’s wild felid populations is currently unknown, there is the potential for this disorder to negatively affect the continued recovery of the panther.
Analysis of Kit Fox Occupancy in the Trans-Pecos, Texas
Matthew Hewitt; Dana Karelus; Patricia Moody Harveson; Louis Harveson; Russell Martin
Management of a species requires knowledge of their distribution and the environmental features that influence their use of an area. The kit fox (Vulpes macrotis) is a small fox species endemic to the threatened desert grasslands of the western United States and northern Mexico. Detailed distribution information on their range in Texas was lacking, but the state had documented population declines in the closely related swift fox (Vuples velox). Therefore, our objectives were to investigate kit fox occupancy, and the environmental features influencing their distribution, across their broad suspected range in Texas, the Trans-Pecos (81,482 km2), and create a predictive occupancy map for the region. We conducted camera trap surveys at 772 baited sites from March 2018 to March 2020, with each survey lasting 14 days on average (11,205 trap-days). We captured 339 one-hour independent kit fox photos at 105 camera survey sites. We divided surveys into 3-day sampling occasions and fit single season occupancy models and tested for an effect of sampling occasion on detection and for additive effects of slope, elevation, shrub height, and shrub cover on occupancy. Overall detection ± standard error was 0.46 ± 0.04 and was influenced by sampling occasion, whereby detection was highest on the first occasion and decreased afterwards. Average overall occupancy for surveys was 0.16 ± 0.01 (range: 0.00-0.82) and was influenced by all 4 environmental covariates, with greatest occupancy where there were gentler slopes, lower elevations, and shorter shrubs covering less of the area. We used the model to make a predictive map of occupancy across the Trans-Pecos region and overlaid kit fox sightings from other sources. Our work provides detailed baseline information on kit fox distribution in the region and can be used to help inform future research and monitoring efforts for the species.
A Rabbit’s Tale: Genomic Assessment of Pygmy Rabbit Populations Including the Endangered Columbia Basin Pygmy Rabbit
Stacey A. Nerkowski; Paul A. Hohenlohe; Kenneth I. Warheit; Lisette P. Waits
Loss and fragmentation of habitat has led to the near extirpation of the disjunct pygmy rabbit (Brachylagus idahoensis) population in the Columbia Basin (CB) of Washington State. In 2003, the CB pygmy rabbit (CBPYRA) was listed as an endangered distinct population segment under the US Endangered Species Act. In 2001, sixteen CBPYRA were taken from the last remaining population in Washington to start a captive breeding program, and four Idaho rabbits were added to counteract the effects of inbreeding. Rabbits were moved to semi-wild breeding enclosures in 2011, and additional rabbits were translocated from other populations within the western United States. Since then ~2000 mixed ancestry rabbits have been released into the wild. To provide insight into genomic diversity and ancestry of CBPYRA populations we must first understand the regional source populations that contribute to these mixed ancestry rabbits. We used restriction site-associated DNA sequencing (RADseq) on 220 rabbit samples representing all regions to generate the first genome-wide set of single nucleotide polymorphism (SNP) markers for this species. PCA and STRUCTURE analyses have identified four genetic clusters: CB, Great Basin, Wyoming/northern Utah and southern Utah. Moderate to significant levels of genetic structure exist between each of the populations (FST=0.12-0.36). Private alleles for each population were identified. Using multiple outlier tests, we identified potential adaptive loci and regions of the genome under selection. From our analysis, we created a 500 loci SNP panel that addresses individual identity, parentage, ancestry, and adaptive loci and applied it to the mixed ancestry wild population in the CB. This panel will allow us to genetically monitor captive and wild populations of CBPYRA to guide strategies for conservation and management.
Natal Survival and Dispersal Influence Population Structure in a Threatened Shorebird
Rose J. Swift; Michael J. Anteau; Kristen S. Ellis; Megan M. Ring; Mark H. Sherfy; Dustin L. Toy; David N. Koons
Natal survival and dispersal have important consequences for populations through the movement of genes and individuals. For species reliant on dynamic habitats, availability and location of appropriate habitat will shift from year-to-year, requiring natal dispersal to locate appropriate breeding habitat. Metapopulation theory predicts either balanced dispersal among regions or source-sink dynamics, which can dramatically change population structure. We quantified natal survival, dispersal probabilities, and dispersal distances in a migratory shorebird, the Piping Plover (Charadrius melodus), with data from four cohorts (n = 2,667) in the Northern Great Plains (NGP). Juvenile survival (fledge to SY) varied among regions and was highest for river (0.77 95% CI [0.65, 0.89]) and lowest for reservoir habitats (0.56 [0.46, 0.66]). Natal fidelity was highest for alkaline wetlands (0.66) and lowest for reservoirs (Lake Sakakawea: 0.28, Lake Oahe: 0.35). As habitat availability decreased, natal dispersal increased. Individuals that hatched later in the breeding season, on reservoir habitats, in areas with high natal chick densities, or less available habitat dispersed farther. Overall, high natal dispersal rates within the NGP indicate high connectivity among distinct regions driven by fluctuating availability of habitat with different water regimes on the Missouri River and in Prairie Pothole wetlands. However, reservoir habitats appear to be ‘sinks’ with low fidelity, low juvenile survival, and high dispersal distances. Our results suggest that plovers in the NGP take advantage of dynamic habitats where they are available in a broad geographic area but further research on adult breeding dispersal is needed to clarify population structure.
Life in the Riparian Zone: Home Ranges and Locomotion of An Endangered Jumping Mouse
Carol L. Chambers; Jennifer L. Zahratka; Charlotte A. Rozanski; José G. Martínez-Fonseca
The New Mexico meadow jumping mouse (Zapus hudsonius luteus) is associated with perennial flowing water, tall, dense herbaceous vegetation, and adjacent upland areas for maternal and day-nest sites in summer and hibernacula in winter. Because the species is federally endangered, knowledge of home ranges and movements can guide management decisions to conserve habitat and promote its recovery. We radio-tracked jumping mice throughout their range (Arizona, New Mexico, Colorado) during their active season in 2017-2019 to identify home range sizes and movements in riparian areas. Home ranges calculated using Minimum Convex Polygon and 95% Kernel Probability averaged 3.96 ha (range 0.36 to 17.9 ha) and 3.35 ha (range 0.11 to 28.4 ha), respectively. Jumping mice stayed close to streams (x̄ = 9 m; maximum x̄ = 40 m), but not exclusively; they moved as far as 550 m from perennial flowing water and >800 m in a single hour. Further, despite being closely associated with riparian corridors, home ranges were not always linear in shape. Mean and maximum distances moved from last location were 68 m and 310 m, respectively. Males appeared to have larger home ranges in June and early July and moved longer distances than females. However, neither sex showed much difference between maximum and average distances moved from stream. We documented jumping mice using habitat at different scales with various movement strategies including jumping, swimming and diving (probably using the downstream current to their advantage) and climbing herbaceous and woody vegetation to access food. Because this species hibernates and must complete most of its life history in only a few months, conservation of both riparian corridors and upland habitats to accommodate their long movements and seasonal variations in home ranges is necessary for recovery of the species.
Contrasting Patterns of Demography and Population Viability Among Gopher Tortoise Populations at the Species’ Northern Range Edge
Brian Folt; Jeffrey M. Goessling; Anna M. Tucker; Craig Guyer; Sharon M. Hermann; Ericha Shelton-Nix; Conor P. McGowan
Population viability analyses are useful tools to predict abundance and extinction risk for imperiled species, but model predictions should be improved as new information emerges. In southeastern North America, the federally Threatened gopher tortoise (Gopherus polyphemus) is a keystone species in the diverse and imperiled longleaf pine ecosystem, and population viability analyses have suggested that tortoise populations are declining and characterized by high extinction risk. Here, we report results from a 29-year demographic study of gopher tortoises in southern Alabama, where three populations have been stable while three others have declined. To better understand the demographic vital rates associated with stable and declining populations, we used a multi-state hierarchical mark-recapture model to estimate sex- and stage-specific patterns of demographic vital rates at each population. We then built a predictive population model to project population dynamics and evaluate extinction risk in a population viability context. Population structure did not change significantly at stable populations, but juveniles became less abundant in declining populations over 29 years. Apparent survival varied by age, sex, and site: adults had higher survival than juveniles, but female survival was substantially lower in declining populations. Apparently stable populations with high female survival were predicted to persist over 100 years, but sites with lower female survival are projected to decline, become male-biased, and to be at imminent risk of extirpation. Stable populations are most sensitive to changes in apparent survival of adult females. Because local populations varied greatly in vital rates, our analysis improves upon previous demographic models for gopher tortoises by accounting for population-level variation in demographic patterns and suggests that small tortoise populations can persist when managed effectively with stand thinning and prescribed fire.
Evaluation of Vertebrate Carrion Resource Use and Carcass Preparation Energetics in Burying Beetles
Brandon M. Quinby; J. Curtis Creighton; Elizabeth A. Flaherty
The American burying beetle, Nicrophorus americanus (ABB), has experienced a dramatic decline in abundance and geographic range. Beginning in 1993, laboratory-reared offspring of wild-caught individuals from Block Island, Rhode Island were reintroduced onto Nantucket Island, Massachusetts. Despite an initially successful reintroduction, the population shows little evidence of recruitment and likely requires provisioning of quail carcasses for long-term success. A key requirement of the ABB’s life cycle is the availability of small vertebrate carcasses for reproduction. Reproduction is costly in burying beetles, and physiological trade-offs associated with resource use likely influences metabolic activity. In this study, we investigated carrion use and feeding relationships of local co-occurring burying beetles within an extant and reintroduced population of ABBs using stable isotope analysis (δ13C and δ15N) on elytral samples from live-captured specimens. Additionally, we evaluated the energetic costs associated with carcass preparation in a laboratory population of Nicrophorus orbicollis to determine how resource quality (carcass size) influences metabolic trade-offs in burying beetles. Stable isotope analysis indicated that ABBs are not specializing on avian or mammalian carrion but are using both natural and provisioned carrion for reproduction. On Block Island, estimates for the highest proportional carrion resource used by ABBs was ring-necked pheasant (Phasianus colchicus) at 28% for 2017 and 2018. However, on Nantucket Island, where pheasant are less abundant, estimates for the highest proportional carrion resource used was small mammals at 50% in 2017, and granivorous birds at 65% in 2018. Our energetic results suggest that there is a metabolic size limitation on carcass use. Larger carcasses lead to increased CO2 production for beetles and was significantly influenced by the number of days required to prepare larger carcasses. For successful management and reintroduction of ABBs, managers must consider the composition and availability of carrion and limit intra-/interspecific competition for appropriately sized reproductive carrion.


Contributed Oral Presentations
Location: Virtual Date: Time: -