Contributed Oral Presentations
|Survival and Competing Mortality Risks of Mountain Lions in a Major Metropolitan Area|
|John F. Benson; Jeff A. Sikich; Seth PD Riley|
|Understanding natural and human-caused mortality for top predators persisting in human-dominated landscapes is critical for conserving their populations. We estimated survival and cause-specific mortality rates and investigated factors influencing mortality risk of mountain lions by radio-tracking 58 individuals (33 males, 25 females) across the highly fragmented landscape in greater Los Angeles, California from 2002-2019. Mortality risk did not differ strongly between subadults (annual survival [ŝ] = 0.68, SE = 0.08) and adults (ŝ = 0.81, SE = 0.04). However, the different age-classes were subjected to mortality risks from different sources as subadults were more likely to be killed by conspecifics, whereas adults were more likely to die from human-caused mortality. Male subadults were frequently killed by territorial adult males in the isolated Santa Monica Mountains, mortality that may be exacerbated by substantial anthropogenic barriers to dispersal in this landscape. We also tracked kittens tagged at natal dens in the Santa Monica Mountains and estimated survival to independence to be 0.63 (SE = 0.13). Higher mortality from anthropogenic causes for adults, whose survival has the greatest influence on population growth and extinction probability for mountain lions, highlights the importance of mitigation strategies to reduce human-caused mortality. Our work provides novel information about patterns of survival and mortality of mountain lions from the most urbanized landscape occupied by large carnivores in North America.|
|Temporal Partitioning of Jaguars and Pumas in the Maya Biosphere Reserve of Guatemala|
|Gabriela Palomo-Munoz; Rony Garcia-Anleu; Jeffrey Thompson; Andrew J. Tyre|
|Inter-specific competition is important in structuring large carnivore guilds. The coexistence of ecologically sympatric carnivores is potentially facilitated by differences in species behavior and space use which depends on the position each species occupies in the dominance hierarchy. For example, separating temporal activity and space use, competing species reduce opportunities for competitive interactions. Jaguars (Panthera onca) and pumas (Puma concolor), the two largest Neotropical felids, are morphologically sympatric throughout the jaguars’ range where jaguars are socially dominant over pumas and potentially cause pumas to alter their behavior or habitat use. Using data collected from an array of camera traps in three protected areas in the Maya Biosphere Reserve (MBR) in Guatemala, we compared the temporal patterns of jaguar (dominant predator) and puma (subordinate predator) to examine if they temporally segregate. We collected data over 138 days using 78 double-camera trapping stations equating to 3,593 trapping days, obtaining 179 independent records of jaguars (n = 77) and pumas (n = 102). Overall, jaguars were mostly nocturnal and pumas mostly nocturnal and cathemeral. Jaguars showed peaks of activity at 16:00, 21:00, 23:00, and 02:00, and pumas at 07:00 and 22:00 h. Both species alternated their activity patterns across all protected areas which is evidence of temporal segregation. Moreover, our results suggest that jaguars have a distinct nocturnal activity pattern, whereas pumas were mostly cathemeral which could indicate that pumas have a more plastic activity pattern. Our results suggest that coexistence in the MBR between jaguars and pumas is facilitated by temporal segregation. Examining fine-scale temporal interactions between co-occurring carnivores aids in determining the mechanisms by which morphologically similar species differ their use of resources, especially in smaller protected areas where space might be a limiting factor.|
|Conservation Challenges for a Small and Isolated Mountain Lion Population in Southern California: Carnivore-Livestock Conflict and First Evidence of Inbreeding Depression|
|Seth P. D. Riley; Jeffrey A. Sikich; Audra A. Huffmeyer; Robert K. Wayne|
|Because of their large area requirements, low density, and potential for conflict with humans, large carnivores represent a particular challenge for conservation, especially in landscapes fragmented by freeways and urbanization such as in Southern California. At Santa Monica Mountains National Recreation Area, we have been studying the behavior, ecology, and conservation of mountain lions north of Los Angeles since 2002. The population in the Santa Monica Mountains faces a number of challenges, including anthropogenic mortality sources and major barriers to connectivity, and we have documented very low genetic diversity and repeated instances of close (father-daughter) inbreeding. In early 2020, two new challenges for the population became evident. Adult male P56, one of just two breeding males known in the population at the time, became the first study animal killed on a depredation permit, a potentially significant stochastic demographic event in such a small population. We also saw the first evidence of inbreeding depression. First, we documented evidence of severe teratospermia, characterized as an ejaculate with more than 60% malformed sperm, in two males. They both had 90% abnormal sperm cells, similar to the levels seen in other highly inbred felid populations such as cheetahs and Florida panthers. And in two other males we documented kinks at the distal end of their tails, and one of them was unilaterally cryptorchid (only one teste was descended), both traits regularly seen in highly inbred Florida panthers before genetic rescue. There are a number of current conservation actions planned or underway that could improve the long-term prospects for the population, including changes to depredation policy for mountain lions in coastal California, the potential listing of the species as threatened in parts of the state, and a planned wildlife overpass over the 101 Freeway, the major barrier separating the Santa Monica Mountains from other populations.|
|Functional Responses in Resource Selection by a Habitat Specialist: The Case of Ocelots in South Texas|
|Amanda M. Veals; Joseph D. Holbrook; AnnMarie Blackburn; Michael E. Tewes; Humberto L. Perotto-Baldivieso; Tyler A. Campbell; John H. Young Jr.|
|The distribution of animal populations, and the factors that influence animal use of the landscape, are of key interest to ecologists and managers. Individual animals, and particularly those that are territorial, experience different environmental and habitat conditions, which may generate intraspecific variation in behavioral relationships to those environmental resources. Assessing functional responses in habitat use or selection is a way to uncover patterns of intraspecific variation in resource selection. We assessed functional responses in habitat use for a federally endangered and territorial carnivore, the ocelot (Leopardus pardalis). We examined how spatial and temporal variation influenced ocelot-habitat relationships by leveraging a 35-year (1982-2017) telemetry dataset of 78 ocelots (40 males, 38 females) to evaluate how individual behavior changed across a gradient of environmental conditions. We paired remotely sensed data with telemetry locations of ocelots and assessed habitat use, resource selection, and functional responses. We tested third-order selection models that included vegetation cover, road densities, and traffic volumes, then estimated proportional habitat use. Preliminary results track with previous findings that as habitat specialists, ocelots in south Texas, had a higher probability of use as proportion of woody cover increased in their home range. We saw trends of additive use and consistent selection which are indicative of proportional habitat use. Spatial and temporal variation in habitat availability is likely to have a strong influence on functional responses by ocelots. The insights garnered from our approach can advance habitat conservation efforts and subsequent transportation network planning.|
|Estimating Wolf Abundance in Montana with a Multi-Model Approach|
|Sarah N. Sells; Michael S. Mitchell; Kevin M. Podruzny; Justin A. Gude|
|Estimating wolf (Canis lupus) abundance is a key component of wolf management in Montana. We demonstrate how a multi-model approach reliably estimates wolf abundance by incorporating an occupancy model, a mechanistic territory model, and an empirical group size model. Whereas previous approaches to estimating wolf abundance relied on costly, difficult-to-collect monitoring data, our approach eliminates the need for intensive monitoring and introduces biological models focused on the mechanisms underlying territorial and social behavior. In a three-part process, the occupancy model first estimates the extent of wolf distribution in Montana, based on environmental covariates and hunter-reported wolf observations. The spatially-explicit mechanistic territory model predicts territory sizes using simple behavioral rules and limited data for prey resources, terrain ruggedness, and human density. Together, these two models for area occupied and territory size predict the number of packs in a given area. Finally, a pack size model demonstrates that pack sizes are generally positively related to local densities of prey, and negatively related to terrain ruggedness, local mortalities, and intensity of harvest management. Total abundance estimates for given areas are derived by combining the predicted number of packs and pack sizes. These model-based estimates of wolf abundance in Montana are slightly higher than estimates from previous models or monitoring efforts. Wolf numbers have generally declined since the implementation of harvest, though numbers in recent years have remained more stable even with higher legal harvests.|
|Temporal Scale of Habitat Selection for Large Carnivores: Balancing Energetics, Risk, and Finding Prey|
|Anna C. Nisi; Justin P. Suraci; Laurence Frank; Steve Ekwanga; Alayne Oriol-Cotterill; Terrie M. Williams; Christopher C. Wilmers|
|When navigating heterogeneous landscapes, large carnivores must balance trade-offs between multiple goals, including minimizing energetic expenditure, maintaining access to hunting opportunities, and avoiding potential risk from humans. The relative importance of these goals likely changes from shorter- to longer-term movements, yet our understanding of how drivers of movement behavior change across temporal scale remains limited. Here we quantify how the drivers of habitat selection change with temporal scale for two large carnivore populations living in human-dominated landscapes. We used high-resolution GPS collar data and step selection functions to quantify habitat selection for African lions (Panthera leo) in Laikipia, Kenya and pumas (Puma concolor) in the Santa Cruz Mountains of California across nine temporal scales, ranging from 5 minutes to 24 hours. Analyses considered landscape covariates that are related to energetics, resource acquisition, and risk avoidance. For both species, short-term movement decisions were driven by energetic expenditure and movement efficiency. In contrast, avoiding anthropogenic risk and accessing hunting opportunities were more important at longer time scales. Additionally, pumas experienced a trade-off between energetically efficient movement and avoiding anthropogenic risk. Pumas avoid energetically demanding steep slopes across all temporal scales when risk from humans is low, but in riskier areas, avoiding steep slopes is only important for short-term movement, with longer-term movements driven by risk avoidance. Considering multiple scales of habitat selection can shed light on the animal decision-making process, elucidate trade-offs between conflicting goals, and allow researchers to avoid assumptions about the temporal scale at which a particular behavior operates. In applying multi-scale analysis to fine-grained spatial data, we show that two large carnivore species in very different systems balance competing energetic and safety demands in similar ways as they move through human-dominated landscapes. These commonalities suggest that our results may hold true for other large carnivore species as well.|
|Prioritizing Metapopulation Connectivity for Wolverines|
|Kathleen A. Carroll; Robert M. Inman; Andrew J. Hansen; Kevin Barnett; Rick L. Lawrence|
|Increasing anthropogenic activities (e.g., development) will negatively impact high-elevation species that rely on rural valley bottoms for dispersal, like wolverines (Gulo gulo). Connectivity within the wolverine metapopulation is essential for species persistence in the western US. However, prioritizing areas of connectivity for wolverine conservation presents several challenges: 1) the area that the wolverine metapopulation functions over is large, 2) high-quality and connective wolverine habitats may shift in the future due to climate and human land-use change, and 3) there are many frameworks for approaching prioritization, but none have been applied to wolverines across the western US. We prioritized areas important for wolverine habitat connectivity under future conditions (2050) across western Montana. Criteria for prioritization included 1) an anthropogenic and ecological model, which included genetics, high-quality habitat area, connectivity value, current flow centrality, land development, likelihood of conversion, and road density, 2) an ecological only model with genetics, high-quality habitat area, connectivity value, and current flow centrality, and 3) a connectivity only model with connectivity value. Each of these scenarios represented a systematic conservation planning problem and was solved using integer linear programming. Model output was generated by optimizing 10, 15, and 20% of each variable in the study area in each model while minimizing cost, which resulted in three sets of outputs for each model. We determined which counties in Montana had the highest number of selected parcels and how irreplaceable each of these parcels were in each solution. We found high agreement between our models at the county level and identified specific areas that require immediate conservation action. Our analysis resulted in a set of maps that can be used by land trusts to work with willing private landowners to secure the connectivity of the wolverine metapopulation in the western US over the long term.|
|Vertical Changes in Small Carnivore Community Interactions in the Great Himalayan National Park, Himachal Pradesh|
|Meghna Bandyopadhyay; Ramesh Krishnamurthy|
|The Himalayas exhibit a vertical gradient of heterogeneous habitat providing restricted resources and making them challenging for species survival. Small carnivores are sensitive to any small scale habitat changes especially forest types, and hence serve as indicator species. To understand community interactions in different forest types along the elevation gradient, spatial and temporal interactions and dietary pattern of small carnivores were assessed.
81 camera traps were deployed systematically from 1500m to 4000m for 25 days and 633 small carnivore faeces were collected. Co-occurrence and temporal overlap were estimated using generalized linear mixed models and activity pattern.
In lower temperate forest (LTF) (1500m to 2000m), red fox and leopard cat showed negative spatial (-1.2+0.58) and positive temporal (Δ=0.85) interaction. Whereas in sub-alpine forest (AF) (>3000m) co-detection occurred but with low temporal overlap (Δ=0.36). Yellow throated marten was mostly detected from LTF to sub-AF (1500m to 3500m) whereas stone marten was confined to only AF (>3500m). In higher elevation, stone marten, Siberian weasel, pika, birds are the prey species for red fox and leopard cat whereas in lower elevation they were found to frequently consume rodent and livestock. So with gradual change in forest type, changes in small carnivores interactions and their food consumption were observed. However, the relative abundances of red fox, leopard cat and yellow throated marten were maximum near villages at lower elevations than pristine forests at higher elevations.
The pattern of small carnivore community occurrence and interactions is the reflection of available resources in a given habitat. Changes in small carnivore interactions were found both in human occupied lower to undisturbed higher elevations. It is the forested habitats of different elevations that shape the community structure. This study shows how anthropogenic and natural resources govern the small carnivore community dynamics and is an example of increasing human-wildlife interface.