Genetic and environmental influences on pup mortality risk for wolves and coyotes within a Canis hybrid zone

Benson, John F.; Mills, Kenneth J.; Loveless, Karen M.; Patterson, Brent R.

doi:10.1016/j.biocon.2013.06.018

Cited by 29 publications

(35 citation statements)

References 40 publications

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“…We interpret the strong selection of wetlands and water by canids as reflections of the association of beavers with these habitats (Donkor and Fryxell ) and the importance of beavers as a food resource for canids in central Ontario (Forbes and Theberge ). Furthermore, beaver density is higher in areas with lower stream gradients (Beier and Barrett ) and was negatively associated with elevation in nearby APP (Benson et al ). Thus, predation on beavers may at least partially explain the strong negative association with areas of steeper slopes and higher elevations during summer, when beavers become a more important resource for canids in central Ontario (Forbes and Theberge ).…”

Section: Discussionmentioning

confidence: 99%

Spatiotemporal variation in selection of roads influences mortality risk for canids in an unprotected landscape

Benson

Mahoney

Patterson

2015

Oikos

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Ecologists are increasingly documenting individual variation in resource selection across populations in response to temporal or spatial environmental context. These behavioral patterns are assumed to be adaptive although previous studies have not linked them directly to survival and reproductive data to verify the assumed relationship between behavior and fitness. Recent work documented that higher density of secondary roads within home ranges of free-ranging canids (wolves, coyotes and hybrids) increased mortality risk in the hybrid zone adjacent to Algonquin Park in Ontario, Canada. Here, we examine individual behavioral responses of canids to spatially varying levels of human-disturbance and determine whether these responses to secondary roads resulted in differential mortality risk for canids across the hybrid zone. Specifically, we investigated resource selection within home ranges with GPS telemetry to determine whether canids selected roads more at night than during the day to minimize dangerous encounters with humans. Next, we modeled individual variation in spatial and temporal responses to secondary roads to evaluate the relative importance of intrinsic (Canis ancestry) and extrinsic (resource availability) influences on their behavior. Behavioral responses to roads were not well explained by variation in Canis ancestry. Instead, canids avoided roads more during day than at night as a non-linear function of increased road availability. Furthermore, canids that survived exhibited a stronger relationship between day-night selection of roads and road availability than canids that died suggesting an adaptive nature of this behavior. By modifying their selection of roads between day and night, canids appear to be able to exploit the beneficial attributes of roads while mitigating humancaused mortality risk. However, not all canids responded adaptively highlighting the importance of explicitly linking patterns of resource selection to components of fitness to accurately model and interpret individual variation in resource selection behavior of animals.

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Section: Discussionmentioning

confidence: 99%

Spatiotemporal variation in selection of roads influences mortality risk for canids in an unprotected landscape

Benson

Mahoney

Patterson

2015

Oikos

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“…Technology facilitating tracking of individually marked juvenile animals has become increasingly available for a variety of species, allowing for more direct estimation of juvenile survival and cause-specific mortality rates (e.g. Benson, Mills, Loveless, & Patterson, 2013;Moriarty, Whited, Sikich, & Riley, 2012). However, to date empirical estimates of juvenile survival have mainly been limited to terrestrial species.…”

Section: Introductionmentioning

confidence: 99%

Juvenile survival, competing risks, and spatial variation in mortality risk of a marine apex predator

Benson

Jorgensen

O’Sullivan

et al. 2018

Journal of Applied Ecology

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Reliable estimates of mortality have been a major gap in our understanding of population ecology for marine animals. This is especially true for juveniles, which are often the most vulnerable age class and whose survival can strongly influence population growth. Thousands of pop‐up archival satellite tags (PAT) have been deployed on a variety of marine species, but analysis of these data has mainly been restricted to movement ecology and post‐handling survival following fisheries bycatch. We used PAT data to provide empirical estimates of annual survival and cause‐specific mortality for juveniles of a marine top predator. We tagged and tracked juvenile white sharks in the north eastern Pacific Ocean to (1) estimate survival rates and competing risks and (2) investigate intrinsic and environmental influences on mortality risk. We also evaluated the use of PAT data with respect to meeting assumptions of known‐fate survival models. Annual juvenile survival rate was 0.632 (SE = 0.15) and annual natural mortality rate (0.08, SE = 0.06) was lower than the rate of gillnet interactions (0.48, SE = 0.15). Mortality risk decreased with greater body length and was significantly greater (hazard ratio = 9.05, SE = 0.70) for juvenile sharks in Mexican waters, relative to California waters. The PAT data allowed for unambiguous determination of fate in most cases, aided by collaborative relationships with fishers and secondary tags deployed on a subset of sharks. Although caution must be exercised to establish whether assumptions are met, our work demonstrates that PAT data represent a widely available, untapped data source that could dramatically increase our understanding of marine population ecology. Synthesis and applications. Our research shows fisheries bycatch to be the main source of mortality for juvenile white sharks in the northeastern Pacific Ocean, highlighting the need for best practices, such as releasing sharks quickly following incidental capture. Furthermore, mortality risk for juveniles was greater in Mexican waters, such that survival may be lower in colder years when juveniles are likely to move south seeking warmer water. This could increase stochasticity in juvenile survival and negatively influence population growth for this apex predator.

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“…These investigations are seldom representative of lifetime maternal fitness (Badyaev & Uller, ; Marshall & Uller, ; Plaistow, St. Clair, Grant, & Benton, ), particularly because maternal effects in one reproductive season may not be predictive of future reproduction due to fluctuations in predation pressures (Marshall & Keough, ; Sheriff, Krebs, & Boonstra, ), population densities (Dantzer et al, ; Plaistow & Benton, ), and resources (Forest, Dender, Pitcher, & Semeniuk, ; Hafer, Ebil, Uller, & Pike, ; Plaistow et al, ). While time is an important component of parental effects theory, particularly because such processes are inextricably linked with a mother's ability to translate temporally‐varying environmental conditions into offspring phenotypes (Uller, ), few studies have investigated variation in maternal effects over time (Benson, Mills, Loveless, & Patterson, ; Marshall & Keough, ; Plaistow et al, ; Sheriff et al, ).…”

Section: Introductionmentioning

confidence: 99%

Parental habituation to human disturbance over time reduces fear of humans in coyote offspring

Schell

Young

Lonsdorf

et al. 2018

Ecology and Evolution

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A fundamental tenet of maternal effects assumes that maternal variance over time should have discordant consequences for offspring traits across litters. Yet, seldom are parents observed across multiple reproductive bouts, with few studies considering anthropogenic disturbances as an ecological driver of maternal effects. We observed captive coyote (Canis latrans) pairs over two successive litters to determine whether among‐litter differences in behavior (i.e., risk‐taking) and hormones (i.e., cortisol and testosterone) corresponded with parental plasticity in habituation. Thus, we explicitly test the hypothesis that accumulating experiences of anthropogenic disturbance reduces parental fear across reproductive bouts, which should have disparate phenotypic consequences for first‐ and second‐litter offspring. To quantify risk‐taking behavior, we used foraging assays from 5–15 weeks of age with a human observer present as a proxy for human disturbance. At 5, 10, and 15 weeks of age, we collected shaved hair to quantify pup hormone levels. We then used a quantitative genetic approach to estimate heritability, repeatability, and between‐trait correlations. We found that parents were riskier (i.e., foraged more frequently) with their second versus first litters, supporting our prediction that parents become increasingly habituated over time. Second‐litter pups were also less risk‐averse than their first‐litter siblings. Heritability for all traits did not differ from zero (0.001–0.018); however, we found moderate support for repeatability in all observed traits (r = 0.085–0.421). Lastly, we found evidence of positive phenotypic and cohort correlations among pup traits, implying that cohort identity (i.e., common environment) contributes to the development of phenotypic syndromes in coyote pups. Our results suggest that parental habituation may be an ecological cue for offspring to reduce their fear response, thus emphasizing the role of parental plasticity in shaping their pups’ behavioral and hormonal responses toward humans.

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Genetic and environmental influences on pup mortality risk for wolves and coyotes within a Canis hybrid zone

Cited by 29 publications

References 40 publications

Spatiotemporal variation in selection of roads influences mortality risk for canids in an unprotected landscape

Spatiotemporal variation in selection of roads influences mortality risk for canids in an unprotected landscape

Juvenile survival, competing risks, and spatial variation in mortality risk of a marine apex predator

Parental habituation to human disturbance over time reduces fear of humans in coyote offspring

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