Wildlife are Individuals, Too: Considering Inter-Individual Variation to Inform Management

Symposium
ROOM: Room 230 – Pecos
SESSION NUMBER: 44
 
Individuals have distinctive behavioral traits (or personalities) that contribute to population-level processes. These traits can be inherited but are also malleable to individual, social, and environmental conditions. Unfortunately, there is a disconnect between basic ecological and evolutionary science, which embraces behavioral traits as a mediating factor for individual fitness, and applied wildlife management, which tends to look only at population averages. The latter tends to ignore inter-individual variation in behavioral traits, which can influence empirical estimates of many topics common in the applied literature, including population size and structure, models of resource selection and population dynamics, harvest management, responses to disturbance, adaptation to novel environments, and reintroduction success. Understanding why or how individual variation in behavioral traits occurs and contributes to population-level responses will be useful for management and conservation of species, particularly under the ever-changing circumstances prevalent on many landscapes (e.g., climate change, urbanization, invasive species). This symposium will synthesize our current knowledge of behavioral traits in wildlife populations at several scales and provide a platform to enhance understanding, research, and applications for wildlife management. Specifically, the symposium will cover behavioral traits and how they are important for wildlife management at three levels: 1) fine-scale choices; 2) behavior and interactions with conspecifics; and 3) landscape-level processes.

1:10PM Wildlife Are Individuals Too: Considering Inter-Individual Variation to Inform Management
  Melissa J. Merrick; John Koprowski
Individually distinctive behavioral traits, or personalities, contribute to population-level processes and ecological interactions important in applied wildlife conservation research. Inter-individual variation in behavioral traits (personality) and correlation among behavioral traits (behavioral syndromes), can influence empirical estimates of population size and structure, models of resource selection and population dynamics, harvest and control in wildlife and fisheries populations, population response to disturbance and novel environments, and the success of reintroductions. Despite the important role that personality and behavioral syndromes play in the ecology and dynamics of wildlife populations, a disconnect between basic and applied research realms continues. While the concept of animal personalities and their role in ecology and evolution is increasingly embraced in the animal behavior, ecology, and evolutionary biology literature, its role in in applied wildlife management and conservation has not yet been fully explored. We identify 10 research foci, often considered the domain of applied wildlife management and conservation, summarize examples of how these research domains may be influenced by personality and behavioral syndromes, and outline potential implications. We suggest that a focus on individuals in wildlife conservation study can provide an additional perspective that may be fruitful in maximizing our effectiveness in management, conservation, and recovery of populations.
1:30PM Specialization in Foraging Strategies of Coyotes
  Seth D. Newsome; Erich M. Muntz; Evan C. Wilson; Stanley D. Gehrt
Synanthropic carnivores offer unique opportunities to study inter-individual variation in resource and habitat use, and better understand how these key aspects of a species ecology influence human-wildlife conflicts. As coyotes continue to increase their range and rapidly colonize virtually every habitat across North America, it’s important to identify the cause(s) of human-coyote conflicts so that appropriate management actions can be taken to minimize negative interactions, which likely have implications for managing other synanthropic carnivores. Here we combine individual-level movement patterns with diet composition based on stable isotope analysis to evaluate hypotheses for human-coyote conflicts in two novel environments recently colonized by coyotes: Chicago, Illinois and Cape Breton Highlands National Park, Nova Scotia. We found that natural and anthropogenic resources in both areas can be reliably partitioned with carbon (δ13C) and in some cases nitrogen (δ15N) isotopes, and we used mixing models to quantify the relative proportion of these two general prey types consumed by individuals in both populations. In Chicago, we found a large degree of individual variation in diet, however, anthropogenic resources were only important for a few individuals, most of which occupied the downtown core of the city. Likewise, most individuals (<15%) in the more pristine environment of Cape Breton relied on natural prey (moose and snowshoe hare), and all individual coyotes involved in conflicts with humans in this area did not consume anthropogenic resources. Overall, our results suggest that habituation to humans via consumption of anthropogenic foods does not play a substantive role in human-coyote conflicts in these contrasting urban and pristine environments. In contrast to the expectation that urban adaptation may dampen ecological variation, our results also suggest individuality exemplifies the successful establishment of coyotes in urban Chicago and that direct anthropogenic food subsidization may not be a prerequisite for successful adaptation to urban environments.
1:50PM Individual Variation in Avian Avoidance Behaviours in Response to Repeated, Simulated Vehicle Approach
  Travis L. DeVault; Thomas W. Seamans; Bradley F. Blackwell; Steven L. Lima; Esteban Fernandez-Juricic
Birds exhibit variation in alert and flight behaviours in response to vehicles within and between species, but it is unclear how properties inherent to individuals influence variation in avoidance responses over time. We examined individual variation in avoidance behaviours of brown-headed cowbirds (Molothrus ater) in response to repeated presentation of a simulated vehicle approach in a video playback scenario. We modeled temporal alert and flight behaviours to determine whether overall behavioural variation resulted primarily from variation within (i.e., intraindividual variation) or between individuals. We examined reaction norms (individual × treatment day) and whether birds showed plasticity in responses via habituation or sensitization. Repeatability in the response metrics for individuals was low (~0.22 for alert and flight), indicating that model variation was due primarily to intraindividual variation rather than between-individual variation. We observed sensitization in alert responses over time, but no sensitization or habituation in flight responses. Our results indicate that individuals learned to anticipate the vehicle approach but did not vary their escape behaviour, suggesting that alert and flight behaviour might be affected differently by cues associated with oncoming objects or experience with them. We consider our findings in light of the ongoing development of strategies to reduce animal-vehicle collisions.
2:10PM Fluctuating Expressionof Individuality over the Reproductive Cycle: Relationshipsbetween Mate Availability and Breeding Behavior in Male White-Tailed Deer
  Tara Gancos Crawford; Bradley S. Cohen; Thomas J. Prebyl; Taylor N. Simoneaux; Michael J. Chamberlain; Karl V. Miller
Most of the published research on individual specialization within wildlife populations describes inter-individual differences in diet or foraging strategy. Few studies have looked at differences in breeding behavior among conspecifics. In polygynous species, males aim to maximize encounters with receptive females while minimizing conflicts with other males. A priori, we hypothesized that during the breeding season, as female receptivity fluctuates, changes in intraspecific competition for available mates would drive individual males occupying different positions within the social dominance hierarchy to adopt different mate search strategies to optimize breeding opportunity tradeoffs. Using telemetry data collected in 2013 and 2014 from 24 adult male white-tailed deer (Odocoileus virginianus) (≥ 3.5 years old), we characterized levels of individual specialization within the male deer population based on individuals’ activity and space-use across four stages of the reproductive cycle (non-breeding, pre-rut, rut, and post-rut). We estimated mate availability (proportion of females receptive) by backdating known parturition dates from vaginal implant transmitter-associated fawning events each spring, then used generalized linear mixed models to examine relationships between population-level measures of individual specialization and mate availability over each stage of the reproductive cycle. Contrary to our expectations, males’ movements and activity patterns were more divergent but temporally consistent during the non-breeding season, preceding the rut and the post-rut. As mate availability increases and peaks during the pre-rut and rut, respectively, individual males’ spatio-temporal behaviors become increasingly variable. Consequently, they become more alike and more representative of the population as a whole.
2:30PM Individual Variation in Urban Coyote Habitat Selection, Diet, and Movement and Implications for Conflict Mitigation
  Maureen H. Murray; Colleen C. St. Clair
Several species of urban-adapted carnivores, including coyotes (Canis latrans), use anthropogenic resources in developed areas, which may increase rates of encounters and conflict with people. These negative interactions might be reduced with more understanding of individual variation in coyote behavior to identify conflict-prone individuals. We examined variation in coyote diet, resource selection, and movement using GPS collars and stable isotope analysis for 19 coyotes captured in Edmonton, Alberta. Among these coyotes, we compared their use of developed urban areas using the day using resource selection functions and anthropogenic food using Bayesian mixing models. We also used step selection functions to compare the road-crossing behavior of coyotes to determine predictors of vehicle mortality. Coyote use of anthropogenic resources was mediated mainly by coyote health. Coyotes with signs of sarcoptic mange (Sarcoptes scabiei, n = 8) were significantly more likely to use residential areas during the day and assimilate anthropogenic food. Likelihood of vehicle collisions, however, was instead associated with the time of road crossings. Individual coyotes that crossed roads mainly at night were significantly less likely to die in collisions than coyotes that remained crepuscular. Our results suggest that human-coyote conflicts may be disproportionately caused by a subset of the population. Further, avoidance of human activity by coyotes appears to be advantageous for survival but may be reduced with increased need for resources. Managers should target their efforts on traits associated with greater use of anthropogenic resources, such as disease in our study, and exploit the behavioral flexibility of coyotes and other urban adapters to encourage avoidance of human activity. Greater appreciation for and inclusion of individual variation in urban wildlife management may reduce human-wildlife conflict while reducing reliance on population reduction programs.
2:50PM Refreshment Break
3:20PM Influence of Conspecifics on Individual Behavior: Group Decision-Making in a Fusion-Fission Society
  Jerod A. Merkle; Marie Sigaud; Daniel Fortin
Individual animals are commonly monitored under the implicit assumption that their behaviors are unaffected by intraspecific interactions. However, individuals of many taxa must deal with conspecifics. This is particularly important for group living animals, where group members that possess differing information about the environment may disagree on collective movement decisions. Such disagreements jeopardize group cohesion, and are therefore a fundamental driver of fusion-fission group dynamics and the distribution of individuals. Our objectives were to 1) evaluate the role of individual knowledge during collective patch choice decisions, 2) determine under what circumstances animals might leave a group, and 3) quantify the impact that following other group members to new places has on human-wildlife conflicts. We examined these objectives using GPS radio-collar data collected 2006-2014 from free-ranging bison (Bison bison) residing in and around Prince Albert National Park (Canada). Owing to their fusion-fission society, we found that individual bison are constantly associating with conspecifics possessing different spatial information. An individual’s movements were derived by both personal information about local foraging options, but also information known by fellow group members. Bison used group familiarity coupled with their knowledge of local foraging options and recent past experience when deciding to follow or leave a group – a tactic that led to energy-rewarding movements. These results provide empirical evidence of an adaptive behavioral strategy for individuals in fusion-fission societies to deal with social disagreements while simultaneously increasing energy intake rate. Finally, we found that following group members with crop raiding experience led to an increased probability of first-time crop-raiding. Such transfer of information led to rapid shift to the entire population crop-raiding within a generation. Natural selection has shaped collective behaviors for coping with social disagreements and resource heterogeneity, which maintain fusion-fission dynamics and play a critical role in animal distribution and human-wildlife conflicts.
3:40PM The Influence of Fear and Hunger on Individual-Based Decision-Making Across a Landscape of Fear
  Michael Sheriff; Catherine E. Pritchard
Prey can mitigate their susceptibility to predation by reducing activity and foraging, but must balance this energetic needs required for daily maintenance and future reproduction; trade-off decision-making likely based on individual fear and nutrition. The influence of these factors on individual-based decision making in wild animals, however, remains little studied, although may be a major driver of habitat selection and within habitat behavior. Here, we measured the behavior of known, individual vicuñas (Vicugna vicugna) living in the high Andes of Argentina and correlated their behavior to individual fear and nutritional status. We collected fecal samples at the beginning and end of a 7-day observation period, to estimate fearfulness (via glucocorticoid metabolites) and nutritional status (via thyroid hormones), and recorded 4x 20min behavioral videos within this period. Vicuñas within our system live in a dyadic predator-prey relationship with pumas (Puma concolor) across a stark landscape of fear, with areas of low risk but also low food availability contrasted against areas of extreme risk and high food availability. This backdrop allows us to compare the interactive relationship between fear, hunger, and behavioral-decision making in both high risk and low risk areas. This study is the first to investigate such an interactive relationship in wild animals and will better our understanding of how animals make decisions relative to both external and internal stressors.
4:00PM The Fat and Furious: Consequences of Risk-Sensitive Allocation of Resources in Long-Lived Herbivores
  Kevin L. Monteith
Studies at the population level have provided the basis for our understanding of the regulation of animal abundance, however, data collection and analyses at the level of the individual are complementary to those at the population level and yield greater insights into underpinning mechanisms. A central tenant of life-history theory concerns how individuals allocate resources to current reproduction versus reserving resources to insure survival. Accordingly, long-lived, iteroparous mammals tend to favor their own survival over current reproduction—a conservative and risk-sensitive strategy of resource allocation that has important and yet, underappreciated implications for understanding life-history and population regulation. Nutritional condition is the product of an individual’s environment and represents internal stores of resources that are a critical source of nutrients to mitigate seasonal rhythms in forage quality and availability, and metabolic demands. Through long-term, individual-based monitoring of nutritional condition, growth, and demography, my colleagues and I evaluated links between nutrition and key life-history traits in Odocoileus. In accordance with life-history theory, seasonal allocation of resources occurred in a risk-sensitive framework; females allocated reserves in a state-dependent manner relative to their availability above seasonal thresholds. Accordingly, mothers that are unable to meet energetic demands of gestation and lactation reduce reproductive output, thereby transferring costs of reproduction to their offspring. Such risk-sensitive allocation to reproduction mechanistically links nutritional condition of the mother to survival and ontogenetic growth of offspring. Indeed, conditions during gestation alone had life-long consequences on growth of offspring. Intergenerational maternal effects can persist through adulthood regardless of improved conditions thereafter—a likely factor leading to cohort effects. Risk-sensitive allocation creates seasonal and generational carryover that has important implications for understanding seasonal contributions to demography, growth and development, life history, and population dynamics of large herbivores, but of which may only be revealed through long-term, individual-based studies.
4:20PM Individual Behavior Differences Are Important Predictors of Natal Dispersal Distance in an Endangered Small Mammal
  Melissa J. Merrick; John L. Koprowski
Natal dispersal distance is an important parameter used in a variety of population models, yet most models rely upon an oversimplified distribution of dispersal distances to inform species’ capacity to move – primarily because we lack data on intra-population heterogeneity in dispersal behavior and dispersal distance. Despite these challenges, characterizing the magnitude of inter-individual variation in dispersal distances and understanding factors that influence such heterogeneity are necessary to model gene flow and functional landscape connectivity, predict recruitment and population persistence, and parameterize species distribution models, particularly in the face of anthropogenic disturbances and habitat fragmentation. Peripheral, isolated populations provide unique opportunities to compare how ecological processes like natal dispersal differ from populations in contiguous landscapes and test hypotheses about important drivers of natal dispersal distance. We quantified natal dispersal distances in an isolated, peripheral small mammal, the Mt. Graham red squirrel (Tamiasciurus fremonti grahamensis), and compared distances to those reported for other red squirrel populations range-wide. We examined the influence of inter-individual behavior differences on natal dispersal distance and subsequent survival in Mt. Graham red squirrels. In this isolated population, natal dispersal is sex biased and male dispersal distances are up to 9 x greater than reported for other North American red squirrel populations. For both sexes, natal dispersal distance was positively associated with an individual’s behavioral tendency for activity and exploration, and individual activity scores and dispersal distances were in turn mediated by mother’s body condition and resource availability. Our results demonstrate how maternal and environmental feedbacks can help maintain behavioral phenotypes as well as highlight the importance of examining population processes at the range periphery in order to characterize species’ movement capacity.
4:40PM Proactive use of reactive behaviour could enhance coexistence with wildlife
  Colleen Cassady St. Clair
Every population appears to exhibit behavioural types, which are often categorized as a proactive-reactive continuum of coping styles. Proactive individuals tend to acquire, interpret, store, and act on information quickly, whereas reactive individuals perform these cognitive processes more slowly and ambivalently. This flexibility appears to be advantageous in changing environments with enough generality to support proactive management of both declining and invasive populations. I provide a framework for exploiting behavioural flexibility as a management tool by (1) identifying the most responsive (a) life stages, (b) cognitive processes, (c) specific behaviours, and (d) anthropogenic threats; (2) targeting the combination of features that maximizes the predicted effect on population size; and (3) manipulating one or both of individuals and environments to reduce (for invasive species) or enhance (for declining species) fitness benefits for reactive individuals. I illustrate these approaches using examples from my own lab that include habituated elk, threatened grizzly bears, urban coyotes, and water-associated birds at anthropogenic sites. Relative to traditional management that targets population averages, an approach that targets reactive individuals may effect more rapid changes to trajectories of conflict vs. coexistence between people and wildlife.

 
Organizers: M. Colter Chitwood, University of Montana, Missoula, MT; Bradley S. Cohen, University of Georgia, Athens, GA; Michael J. Chamberlain, University of Georgia, Athens, GA; Joshua J. Millspaugh, University of Montana, Missoula, MT
 

Symposium
Location: Albuquerque Convention Center Date: September 25, 2017 Time: 1:10 pm - 5:00 pm