Highways, crossing structures and risk: Behaviors of Greater Yellowstone pronghorn elucidate efficacy of road mitigation

Wildlife crossing structures and accompanying barrier fencing can prevent large mammals from accessing road surfaces and can significantly reduce wildlife-vehicle collisions while allowing animals to move from one side of the road to the other. Little research has been conducted on the behavioral responses of wildlife when encountering these novel structures over time. We used the installation of new wildlife road crossing structures built along a 6000-year old migration route to evaluate behavioral responses of long-distance migrators to the structures. We collected behavioral data during and after construction in order to evaluate individuals' immediate responses to these structures and to investigate how they changed over time using generalized linear mixed-effects models and generalized additive models fit by maximum likelihood. Pronghorn acclimated to the crossing structures and the frequency in which they successfully crossed them increased over time. The probability of pronghorn successfully crossing a structure was not influenced by human presence. Pronghorn spent more time in sustained vigilance behaviors after construction. Pronghorn also spent more time in sustained vigilance behaviors at relatively further distances from a structure and lead individuals spent more time in sustained vigilance behaviors than non-lead individuals. We did not detect any significant factors associated with stress behaviors. Pronghorn still demonstrated high sustained vigilance when approaching the structures after 20 months post construction, despite an increase in crossing success. While we found evidence of risk-avoidance behaviors in pronghorn at crossing structures, this work provides evidence that pronghorn gradually acclimated to wildlife crossing structures built in a historical migration corridor in the Greater Yellowstone Ecosystem. We recommend using task completion chronology (rather than project completion dates) to install wildlife mitigation and we recommend using wildlife friendly fencing when fences are required for multiple use (e.g., cattle) at crossing structure entrances. (C) 2018 The Authors. Published by Elsevier B.V

Activity of Bdellovibrio Hit Locus Proteins, Bd0108 and Bd0109, Links Type IVa Pilus Extrusion/Retraction Status to Prey-Independent Growth Signalling

Bdellovibrio bacteriovorus are facultatively predatory bacteria that grow within gram-negative prey, using pili to invade their periplasmic niche. They also grow prey-independently on organic nutrients after undergoing a reversible switch. The nature of the growth switching mechanism has been elusive, but several independent reports suggested mutations in the hit (host-interaction) locus on the Bdellovibrio genome were associated with the transition to preyindependent growth. Pili are essential for prey entry by Bdellovibrio and sequence analysis of the hit locus predicted that it was part of a cluster of Type IVb pilus-associated genes, containing bd0108 and bd0109. In this study we have deleted the whole bd0108 gene, which is unique to Bdellovibrio, and compared its phenotype to strains containing spontaneous mutations in bd0108 and the common natural 42 bp deletion variant of bd0108. We find that deletion of the whole bd0108 gene greatly reduced the extrusion of pili, whereas the 42 bp deletion caused greater pilus extrusion than wild-type. The pili isolated from these strains were comprised of the Type IVa pilin protein; PilA. Attempts to similarly delete gene bd0109, which like bd0108 encodes a periplasmic/secreted protein, were not successful, suggesting that it is likely to be essential for Bdellovibrio viability in any growth mode. Bd0109 has a sugar binding YD- repeat motif and an N-terminus with a putative pilin-like fold and was found to interact directly with Bd0108. These results lead us to propose that the Bd0109/Bd0108 interaction regulates pilus production in Bdellovibrio (possibly by interaction with the pilus fibre at the cell wall), and that the presence (and possibly retraction state) of the pilus feeds back to alter the growth state of the Bdellovibrio cell. We further identify a novel small RNA encoded by the hit locus, the transcription of which is altered in different bd0108 mutation background

Territory fidelity, space use, and survival rates of wild coyotes following surgical sterilization

Sterilization of wild canids is being used experimentally in many management applications. Few studies have clearly demonstrated vasectomized and tuballigated canids will retain pair-bonding and territorial behaviors. We tested whether territory fidelity, space use, and survival rates of surgically sterilized coyote (Canis latrans) packs were different from sham-operated coyote packs. We captured and radio-collared 30 coyotes in December 2006. Sixteen of these animals were sterilized via vasectomy or tubal ligation, and 14 were given shamsurgeries (i.e., remained intact). We monitored these animals using telemetry and visual observations through 2 breeding seasons and 1 pup-rearing season from December 2006 to March 2008. Mean pack size was not significantly different between sterile and intact coyote packs. We found no difference in home range size between sterile and intact coyotes. We found differences in home range and core area overlap between sterile and intact coyote packs in some seasons; however, this difference may have existed prior to sterilization. Home range fidelity was not significantly different between sterile and intact coyotes. All coyotes had higher residency rates during the breeding season, with no differences between sterile and intact coyotes. Survival rates were correlated with biological season, but there were no differences in survival rates between sterile and intact coyotes. We concluded that surgical sterilization of coyotes did not affect territory fidelity, survival rates, or home range maintenance

Using sterilization to change predation rates of wild coyotes: A test case involving pronghorn fawns

a b s t r a c t Surgical sterilization of coyotes (Canis latrans) reduced their predation rate on domestic sheep. We investigated whether sterilizing coyotes would similarly change coyote predation rates on pronghorn antelope (Antilocapra americana) neonates. From May 2006 to March 2008, we radio-collared 71 pronghorn fawns to determine survival rates in southeast Colorado, USA. During the first year of the study, all coyotes were reproductively intact. During the second year, we surgically sterilized 15 coyotes from 10 packs in the southern half of the study area, while nine coyotes from seven packs in the northern half were given sham sterilizations (i.e., remained reproductively intact). In addition, we estimated the availability of alternative prey and coyote density on both areas to evaluate predator-prey factors that could interact with the sterilization treatment. Using the known fate model in Program Mark, we constructed models with and without a treatment effect, plus year, area, individual covariates, alternative prey indices, and predator density to estimate pronghorn fawn survival rates. Results from model averaged parameter estimates and cumulative summer survival indicated coyote sterilization increased survival rates of pronghorn fawns by reducing predation rates of fawns. While fawn survival was higher overall in the north area, after treatment was applied, cumulative pronghorn fawn survival during the summer of 2007 in the south area was 242% higher for pronghorn fawns captured in sterile coyote territories (0.44; 79-day interval survival rate) compared to fawns captured in intact coyote territories (0.18). There was also a significant local area effect, but no relationship between fawn survival and individual fawn covariates of sex, birth weight, birth date, or age. No relationship was detected between fawn survival and lagomorph abundance index, rodent abundance index, or coyote density. Surgical sterilization of coyotes was useful in reducing predation rates on pronghorn fawns. Published by Elsevier B.V

Highways, crossing structures and risk: Behaviors of Greater Yellowstone pronghorn elucidate efficacy of road mitigation

Wildlife crossing structures and accompanying barrier fencing can prevent large mammals from accessing road surfaces and can significantly reduce wildlife-vehicle collisions while allowing animals to move from one side of the road to the other. Little research has been conducted on the behavioral responses of wildlife when encountering these novel structures over time. We used the installation of new wildlife road crossing structures built along a 6000-year old migration route to evaluate behavioral responses of long-distance migrators to the structures. We collected behavioral data during and after construction in order to evaluate individuals' immediate responses to these structures and to investigate how they changed over time using generalized linear mixed-effects models and generalized additive models fit by maximum likelihood. Pronghorn acclimated to the crossing structures and the frequency in which they successfully crossed them increased over time. The probability of pronghorn successfully crossing a structure was not influenced by human presence. Pronghorn spent more time in sustained vigilance behaviors after construction. Pronghorn also spent more time in sustained vigilance behaviors at relatively further distances from a structure and lead individuals spent more time in sustained vigilance behaviors than non-lead individuals. We did not detect any significant factors associated with stress behaviors. Pronghorn still demonstrated high sustained vigilance when approaching the structures after 20 months post construction, despite an increase in crossing success. While we found evidence of risk-avoidance behaviors in pronghorn at crossing structures, this work provides evidence that pronghorn gradually acclimated to wildlife crossing structures built in a historical migration corridor in the Greater Yellowstone Ecosystem. We recommend using task completion chronology (rather than project completion dates) to install wildlife mitigation and we recommend using wildlife friendly fencing when fences are required for multiple use (e.g., cattle) at crossing structure entrances. Keywords: Antilocapra americana, Behavior, Highway crossing structure, Overpass, Pronghorn, Risk-avoidanc

Using sterilization to change predation rates of wild coyotes: A test case involving pronghorn fawns

Surgical sterilization of coyotes (Canis latrans) reduced their predation rate on domestic sheep. We investigated whether sterilizing coyotes would similarly change coyote predation rates on pronghorn antelope (Antilocapra americana) neonates. From May 2006 to March 2008, we radio-collared 71 pronghorn fawns to determine survival rates in southeast Colorado, USA. During the first year of the study, all coyotes were reproductively intact. During the second year, we surgically sterilized 15 coyotes from 10 packs in the southern half of the study area, while nine coyotes from seven packs in the northern half were given sham sterilizations (i.e., remained reproductively intact). In addition, we estimated the availability of alternative prey and coyote density on both areas to evaluate predator–prey factors that could interact with the sterilization treatment. Using the known fate model in Program Mark, we constructed models with and without a treatment effect, plus year, area, individual covariates, alternative prey indices, and predator density to estimate pronghorn fawn survival rates. Results from model averaged parameter estimates and cumulative summer survival indicated coyote sterilization increased survival rates of pronghorn fawns by reducing predation rates of fawns. While fawn survival was higher overall in the north area, after treatment was applied, cumulative pronghorn fawn survival during the summer of 2007 in the south area was 242% higher for pronghorn fawns captured in sterile coyote territories (0.44; 79-day interval survival rate) compared to fawns captured in intact coyote territories (0.18). There was also a significant local area effect, but no relationship between fawn survival and individual fawn covariates of sex, birth weight, birth date, or age. No relationship was detected between fawn survival and lagomorph abundance index, rodent abundance index, or coyote density. Surgical sterilization of coyotes was useful in reducing predation rates on pronghorn fawns

Sub-lethal effects of energy development on a migratory mammal—The enigma of North American pronghorn

To meet societal demands for energy, ∼50,000 gas sites are developed annually in North America, among which many are in western less-developed and wildlife rich areas. To evaluate effects of increasing energy infrastructure requires sufficiently robust study designs, an onerous issue given the vastness of scale, limited funds, and an abject dearth of baseline data. Here we address these issues, first by discussion of the type of approaches needed to develop proper inference about potential effects of energy footprints, and subsequently through an empirical approach by examining the biological performances of more than 370 GPS radio-collared adult female pronghorn (Antilocapra americana). A rigorous attempt to examine if industrial development has any impact on pronghorn is based on three assumptions: (i) late-winter body mass reflects a period of inadequate food availability because winter habitat is altered; (ii) variation between population segments reflects spatial differences in food availability, increased energetic costs, or varying survival rates between gas field and non-developed sites; and (iii) reproductive correlates including physiological and immunological markers and adult survival are lower at sites varying in habitat quality. Our study area situated in one of the world’s premier wildlife regions–the southern Greater Yellowstone Ecosystem–harbors approximately 100,000 wintering ungulates, some of North America’s longest migrations, and two of the continent’s largest gas fields. We compared the response of five variables between wild pronghorn in control (not disturbed) and experimental (developed gas fields with well pads, roads, and traffic) sites—pregnancy, chronic stress, immune function, body mass, and adult survival. Despite shifts in animal movements, which included avoidance of energy infrastructure where development is occurring at the highest densities inside two of the largest natural gas fields in North America (Pinedale Anticline Project Area [PAPA] and Jonah fields) and other behavioral or ecological observations of sub-lethal effects, we failed to reject the null hypothesis that development is unrelated to parity in pronghorn biological responses. Studies intent on producing knowledge to assess whether energy development is inimical or not to ungulates will increasingly require appropriate time scales and understanding whether populations are below an expected food ceiling. Further, as with pronghorn in our study region, knowing if individuals are at the limits of their biological range (e.g. altitude) where stressful winter conditions may mask impacts of development is important