Movement Ecology II (hosted by TWS)

Contributed Paper Session

1:10PM Ungulates’ Survival Kit: Migratory Plasticity in the Changing World
Wenjing Xu, Avery Shawler, Kristin Barker, Amy Van Scoyoc, Justine Smith, Owen Bidder, Chelsea Andereozii, Elizabeth Templin, Harshad Karandikar, Steffen Mumme, Arthur Middleton
Ungulate migration is traditionally assumed to be a fixed behavioral trait. When examining impacts of external disturbances and on migration, the question is often limited to whether migration still happens. Recent research highlights that ungulate migration is actually very plastic; animals might alter migratory status (whether), timing (when), route (how), and destination (where) in response to environmental changes. Such behavioral plasticity provides an important adaptive advantage for species in response to disturbances and thus has become critical in understanding how migrants could persist in a rapidly changing world. We reviewed more than 300 studies on ungulate migration change caused by external disturbances, including habitat loss, fragmentation by barriers, over-exploitation, and climate change. To examine all dimensions of migratory plasticity, we classified migration change into four types based on spatial characteristics: i) same route, same starting range, new ending range along the route, ii) new route, same ranges; iii) new route, same starting range, new ending range; iv) new route, new starting/ending ranges. We consider temporal and population changes as super-types that can coincide with the four spatial types. This classification allowed us to examine migratory plasticity across populations, species, landscapes, and types of disturbance. Furthermore, we drew insights from other migratory taxa to discuss general migration mechanisms that can contribute to different types of migration change. As anthropogenic and environmental disturbances continue to alter ecosystems, ungulates with different migratory tactics could be impacted disproportionally. This study provides a theoretical foundation of migratory plasticity that allows conservation managers to explore a broader spectrum of migration conservation measures, from preventing disturbance and facilitating adaptation, to even potentially restoring migration.
1:30PM The Influence of Season and Intraspecific Competition in the Translocation of American Red Squirrels
Marina Morandini, Melissa Merrick, John Koprowski
The evaluation of the translocation success is a fundamental step to address future conservation efforts. When the target species is an endangered species, such approach can use a common closely related species as surrogate to improve knowledge of the likely outcomes before undertaking translocations of the endangered species. This is the case for Mt. Graham Red Squirrel (Tamiasciurus fremonti grahamianebsi), the rarest mammal in the United States after the extreme decrease of its population caused by a wild fire in 2017. Given the critical status of this population, different active conservation strategies need to be implemented, hence we assessed the efficacy of different translocation strategies using as model species the nearest population of non-endangered red squirrels in the White Mountains (AZ). Preliminary results on the 22 red squirrels traslocated revealed that season influenced the release site fidelity. Squirrels showed a stronger homing response during the fall than in winter. Moreover, in winter squirrels settled within 500 m from the release site, while in the fall 900 m. The space use pattern recorded could be explained by food availability and intraspecific competition. While thefall is characterized by large food resources available that would allow squirrels to easily settle in most of the areas around the release site, it is also the season with a high intraspecific competition due to juvenile’s dispersal. During the fall, all animals were chased away by juveniles, while in the winter it only happened in 20% of the cases by adult resident squirrels. The use of artificial food supplement in the winter and the reduced population density in the release sites because of natural juvenile mortality, allowed red squirrels to successfully settle within 500 m from the release site, making the winter season the most successful period for traslocation.
1:50PM Selection of Summer Feeding Sites by Female Migratory Caribou Using Camera Collars
Sophiane Béland, Martin Bernier, Steeve Côté
Migratory caribou (Rangifer tarandus caribou) are socioeconomically and culturally important for northern communities. Several herds have experienced sharp declines over the last decades. Female migratory caribou depend on the availability of summer habitat resources to meet the needs associated with lactation and the accumulation of reserves for other seasons, when resources are less abundant. Habitat selection of migratory caribou has been assessed at various spatial scales (e.g. population and individual home ranges) but finer scale assessments have been difficult to perform because of the large scales at which habitat data are usually available. Due to these limitations, information on how female migratory caribou select habitat and resources at a fine spatial scale (i.e. feeding sites) is lacking. To document selection of summer feeding sites, we equipped 35 female caribou with camera collars in 2016 and 2017 in northern Quebec (Canada). We collected a total of 43,715 videos of 10 seconds between June 1st and September 1st of each year. We compared sites used for feeding (defined as used) and sites used for any other activity (defined as available) at the habitat and resource scales using resource selection functions. In both years, wetlands were highly selected as feeding sites in June and July while they were avoided in August. Shrublands were mostly selected in July and August. Herbaceous tundra was selected in 2016, but avoided in 2017. At the resources scale, lichen, birch, willow and mushrooms were the preferred resources. Our results provide precise and novel information on the feeding sites selected by female caribou. This information will help understanding foraging patterns and define essential summer habitats of female migratory caribou and will contribute to the management and conservation of the species.
2:10PM Using Seasonal Landscape Models to Predict Space Use and Migratory Patterns of an Arctic Ungulate
Andy Baltensperger, Kyle Joly
Caribou (Rangifer tarandus) in the Western Arctic Herd undertake one of the longest, remaining intact migrations of terrestrial mammals in the world. They are also the most important subsistence resource for many northern rural residents, who rely on the caribou’s migratory movements to bring them near for harvest. To predict changes in distribution and shifting migratory areas over the past decade, we used GPS telemetry data from adult females to develop predictive ecological niche models of caribou across northwestern Alaska. We employed the machine-learning algorithm, TreeNet, to analyze interactive, multivariate relationships between telemetry locations and 37 spatial environmental layers and to predict the distributions of caribou during spring, calving season, insect-harassment season, late summer, fall, and winter from 2009 to 2017. Model results were analyzed to identify regions of repeated predicted use, quantify mean longitude, predict land cover selection, and track migratory changes over time. Distribution models were independently validated and accurately predicted caribou at a spatially-explicit, 500-m scale. Model analyses identified migratory areas that shifted annually across the region, but which predicted 4 main areas of repeated use. Niche models were defined largely by non-linear relationships with coastally-influenced, climatic variables, especially snow-free date, potential evapo-transpiration, growing season length, proximity to sea ice, winter precipitation and fall temperature. Proximity to roads and villages were also important and we predicted caribou to occur 25 km or more from these features. Caribou were predicted to occur in warmer, snow-free and treeless areas that would be conducive for travel and foraging. Rapidly changing seasonal climates and coastal influences that determine forage availability, and human impediments that slow or divert movements are related to geographically and phenologically dynamic migration patterns that may periodically shift caribou away from traditional harvest areas.
2:30PM Occupancy Patterns in a Re-Establishing Fisher Population Following Reintroduction on Washington’s Olympic Peninsula
Kurt Jenkins, Patricia Happe, Rebecca McCaffery, Jeffrey Lewis, Kristine Pilgrim, Michael Schwartz
Species translocation is a primary tool used to restore imperiled wildlife populations. Monitoring population performance following translocation is key to assessing restoration planning assumptions and successes. From 2013-16 we deployed 788 motion-sensing cameras and hair(DNA)-snaring devices to (1) determine occupancy patterns of a reintroduced fisher (Pekania pennanti) population on Washington’s Olympic Peninsula 3-6 years following translocation, (2) examine habitat suitability assumptions made prior to reintroduction, and (3) determine if the population had successfully reproduced in their new habitat. We hypothesized that fisher occupancy would be associated with landscapes characterized by high proportional coverage of dense canopy and mid-sized-to-large trees, a diversity of stand structural classes, and boundary areas separating wilderness from more intensively managed forest lands. We detected fishers across all land management designations, and found negligible support for hypotheses that fisher occupancy was related to forest cover density, tree-size-class, or size-class diversity. Preliminary results indicate fishers were strongly associated with a 5-km swath of lands near the forest wilderness boundary. Fisher occupancy shifted toward the west and south along a precipitation gradient during the study, indicating that population distribution had not yet stabilized. We postulate that the boundary between wilderness and intensively managed forest lands provided fishers with the most suitable prey offerings in proximity to contiguous expanses of low-to mid- elevation old-growth forests that provided optimal resting, denning, and security values. Preliminary results also indicated that at least two generations of fishers have been produced on the Peninsula. Annual occupancy rates across the Peninsula (0.08-0.24), however, were lower than in previously studied established fisher populations, indicating that not all potential fisher habitat was fully occupied or initial habitat suitability estimates were overestimated. The distribution of fishers on Washington’s Olympic Peninsula raises several questions to guide future research on fisher-habitat relationships in coastal forest ecosystems of the Pacific Northwest.
2:50PM Refreshment Break
3:20PM Evaluation of a Black-Tailed Prairie Dog Restoration Via Translocation in the Trans-Pecos Ecoregion of Texas
Barbara Sugarman, Bonnie Warnock, Patricia Harveson, Sean Graham, Russell Martin
Prairie dog (Cynomys spp.) populations throughout North America have declined because of sylvatic plague (Yersinia pestis), shooting, poisoning, and habitat conversion. To aid this keystone species, wildlife managers have used translocation to restore prairie dogs to areas of extirpation. In this study, we translocated black-tailed prairie dogs (C. ludovicianus) to a site on private property 60 km from Alpine, TX. We prepared the translocation site by installing nesting boxes, tubes, and retention baskets and trimmed surrounding vegetation to a height of 15 cm or less to prevent the immediate dispersal of the prairie dogs. The prairie dogs were captured from Marathon, TX (n = 156) and from Lubbock, TX (n = 59); all 215 prairie dogs were translocated to the same site. The prairie dog population at the translocation site was regularly monitored post-translocation and predators were removed from the site. Vegetation was measured pre-translocation and post-translocation to assess the ecological impacts of prairie dog reintroduction. Fecal samples (n = 39) from prairie dogs were taken to measure glucocorticoid levels during the capture of 153 prairie dogs from Marathon, TX and at 2 week, 4 weeks, and 8-12 weeks post-translocation at the translocation site. We analyzed the effects of translocation on the stress level of the prairie dogs over time. This study will help wildlife managers with future translocations of prairie dogs and will aid in the restoration of black-tailed prairie dogs to their extirpated habitat in the Trans-Pecos ecoregion of Texas.
3:40PM Movements of Translocated Southeastern Pocket Gophers (Geomys Pinetis) in Georgia
JT Pynne, Steven Castleberry, L. Mike Conner, Elizabeth Parsons, Robert Gitzen, Sarah Duncan, Robert McCleery, James D. Austin
Southeastern pocket gophers (Geomys pinetis) are endemic to southeastern open pine forests and are ecologically important because they aerate soils, provide shelter for commensal species, and perform selective herbivory. Southeastern pocket gophers have been extirpated from much of their original range due to habitat loss, but efforts to restore open pine communities have led to interests in translocation as a conservation approach to restore populations. Therefore, we assessed translocation methodologies by evaluating soft and hard releases of 24 individuals (11 female, 13 male). For soft releases, we used a custom plow to establish a tunnel system, whereas for hard releases, individuals were released into a shallow (100-cm wide by 20-cm deep) hole. Pocket gophers were radiotagged and tracked every other day until mortality or transmitter failure. Translocated pocket gophers created a mean of 3.7 new mounds/week. Mean distance moved by all individuals was 21.9 m (SE=5.4 m), and frequent above-ground movements were made for both release types. There was no difference (t18 = -0.751, P = 0.462) in mean distance moved between soft- (26.2 m, SE = 8.4 m) and hard-released (18.0, SE = 6.1 m) individuals. Eleven pocket gophers survived until transmitter failure. Mortality rates for soft- (46%) and hard- (61%) individuals were not different (χ21 = 0.0525, P = 0.819). Although we hypothesized that above-ground movements would expose translocated pocket gophers to greater predation risk, only 17% (4 out of 24) of translocated pocket gophers were predated (1 soft and 3 hard release). However, 54% died overall from predation or other causes. Our results are consistent with studies of other pocket gopher species that suggest translocation may be a viable method for their populations, although the mortality rate we observed indicates that greater numbers of southeastern pocket gophers may be needed for successful population establishment.
4:00PM Plasticity in Migratory Behaviors of Male Bighorn Sheep
Kristin Denryter, Kevin Monteith, Tom Stephenson
Migration is an adaptation to seasonal environments that is functionally important to population demographics. Among north-temperate ungulates, migratory behaviors of males are poorly understood compared to females, hence, our objectives were to better understand migratory behaviors of males and determine if body fat influenced migratory strategy. We fit models of elevational migration to GPS locations of male Sierra Nevada bighorn sheep (Ovis canadensis sierrae)—a federally endangered subspecies—to categorize migratory behaviors; created a continuous index of migration to quantify intermediate migratory behaviors; and assessed relations between body fat and migratory strategy. Migration was the predominant migratory strategy of male Sierra bighorn (n = 129 animal-years), followed by residency (n = 27). We identified two intermediate migratory strategies: n = 12 migrants made multiple round-trip movements between seasonal ranges and n = 15 residents wintered high, but moved down in elevation for ≤30 days in late spring–early summer. Among n = 69 potential strategy-switching events (i.e., males tracked for ≥2 years), n = 7 switches occurred (<50% the rate of switching reported for females). Body fat levels of resident males in autumn (17.8 ± 1.7%; n = 5) and spring (8.6 ± 0.4%; n = 10) were slightly greater than those of migratory males in autumn (17.1 ± 0.9%; n = 34) and spring (7.6 ± 0.2%; n = 38). Our results indicate that males switched migratory strategies less frequently than females and body fat influenced choice of migratory strategy. Our continuous metric of migration has utility in analyses of survival and other management questions because it accommodates the spectrum of migratory behaviors exhibited by ungulates, rather than forcing individuals into a false dichotomy of migratory behaviors. Results from our work exemplify the importance of accounting for unique physiology and behavior of male ungulates in their conservation and management.
4:20PM Management of Wildlife Migration and Movement in Idaho: Keeping the PATH CLEAR.
Gregg Servheen, Renee Seidler, Scott Bergen
Wildlife migration and movement is an increasingly important management issue. Science and technology is continuing to provide the specifics on the importance of migration and movement to sustaining species and their ecosystems. But the very rapid pace of human population growth and land use changes in nearly every western state; the cross-cutting nature of the topic to land, population, and habitat managers; and the relatively high cost of any migration management actions all call for new solutions, partnerships, funding, and collaboration and the time needed to grow positive conservation outcomes. The Department of Interior’s SO 3362 has helped bring attention and capacity to this issue in the 11 western states, including Idaho. We discuss the five identified priority areas in Idaho’s SO 3362 state plan and actions being taken across the state to address wildlife migration and movement in the context of the existing science and the management challenges outlined here. In particular, we discuss efforts to develop a more comprehensive road kill database to inform Department of Transportation projects and the different management and communication strategies we are taking to effect positive outcomes for wildlife migration and movement.
4:40PM Pronghorn Translocation to Chihuahua Mexico: Survivorship and Movement Patterns
Carlos Alberto Lopez González, Chritian Delfin Alfonso, Nalleli Lara Diaz, Sarahim Paz Duran
Pronghorn (Antilocapra americana) are considered an endangered species throughout its range, population estimates from Chihuahua range from 300 to 450 individuals. Our objective was to increase the population size through the translocation of animals from New Mexico, assess their survivorship and movement patterns. After a habitat assessment, we released in November of 2018 a total of 100 pronghorns (30 were fitted with radio-transmitters) into two privately owned ranches in northwestern Chihuahua. Capture related mortality was estimated at 20%, this resulted from a 28 h confinement and travel across the border, these events took place up to 12 days after the release. We had one depredation by puma 90 days after release. The rest of the individuals are alive. Individual home range size (mean ± SD) is different at both sites, 513.9 ± 513.9 km2 (n = 5) and 133.19 ± 58.04 km2 (n = 8), linear distance traveled was not significantly different between sites, although there were differences in home size, related to habitat quality, livestock numbers and shrub cover. We documented two dispersal events with a linear distance of 75 km. We had documented the mixture of translocated and native pronghorns in seven different groups, this should result in an increase genetic diversity and larger population size in the short and medium term. Coyote control should be legally implemented at least for short periods of time to increase the possibility of fawn survival, of added importance if the removal of shrubs to increase natural grasslands extension in the region.



Contributed Paper Session
Location: Reno-Sparks CC Date: October 3, 2019 Time: 1:10 pm - 5:00 pm