Habitat selection is a complex hierarchical process and in ungulates typically varies at broad spatial and temporal scales and among individuals. Recent advancements in the ability of global positioning system (GPS)‐collars to collect activity data provide opportunities to understand underlying mechanisms or trade‐offs responsible for fine‐scale variation in habitat selection. Based on data from 64 female black‐tailed deer (Odocoileus hemionus columbianus) fitted with GPS‐collars in northern California, USA, between 2004 and 2013, we first investigated habitat selection at the home range scale. We then used data from a subset of 27 individuals to determine if habitat selection within home ranges was influenced by activity states (active or inactive). Habitat selection by black‐tailed deer varied between summer and winter and was mostly explained by differences in elevation, terrain, and vegetation. Within their home ranges, black‐tailed deer showed fine‐scale selection for habitats that varied with activity states. In summer, selection for edge density and forest types varied across activity states highlighting important fine‐scale selection patterns. Activity state also affected our conclusions about the selection of habitats including slope, canopy cover, and forest types by black‐tailed deer in winter. During both seasons, deer selected for apparently secure habitat when inactive, likely to minimize risk of predation. These results highlight the importance of considering activity states when evaluating habitat selection from animal location data. This is particularly important in multi‐use landscapes such as national forests where habitat needs of ungulates are important considerations in management decisions, including timber harvest. © 2018 The Wildlife Society.
Site fidelity and philopatry are behavioral adaptations found in many species and their fitness benefits are well documented. The combined population level consequences of site fidelity and philopatry, however, have received little attention despite their importance for understanding spatial patterns in connectivity and population dynamics. We used an integrative approach to explore consequences of fidelity and philopatry on the fine-scale genetic structure of black-tailed deer (Odocoileus hemionus columbianus). We assessed fidelity to seasonal home ranges based on location data from 64 female deer fitted with global positioning system (GPS) collars between 2004 and 2013. We assessed philopatry from mitochondrial DNA (mtDNA) haplotypes using DNA extracted from 48 deer. Results based on location data revealed very small movements and seasonal home ranges together with high site fidelity. Fidelity improved survival; every 1 km increase in mean interlocation distances between consecutive summers increased the risk of mortality by 56.5%. Results from mtDNA sequencing revealed high genetic differentiation (F ST > 0.30) and low haplotype sharing among geographic areas separated by as little as 4-10 km. The high genetic differentiation indicated multigenerational periods of philopatric behavior in the matrilineage of black-tailed deer. Combined these results suggest that site fidelity together with strong sex-biased philopatry can create marked short-and long-term demographic isolation and trap matriarchal units as a subset of the larger population with locally determined vital rates. Where such fine-scale population structuring as a consequence of fidelity and philopatry occurs, matrilineal groups might in some cases best serve as the basic units of conservation and management.
Many predators specialize on one or several prey species that they select from the range of potential prey. Predator specialization on primary versus alternative prey is driven in part by encounter rates with prey and a predator’s habitat selection. Although habitat selection changes with behavioural state, this has not been well‐recognized in the resource selection function (RSF) literature to date, often because auxiliary data on the predator’s behavioural states (e.g. hunting) are absent. We monitored habitat selection of pumas Puma concolor in a multi‐prey system in northern California, where pumas specialized on black‐tailed deer Odocoileus hemionus columbianus. We employed multiple RSF analyses on different datasets to test the following three hypotheses: (1) Pumas utilize habitats in proportion to their availability; (2) Pumas select specific habitat features when killing black‐tailed deer, their primary prey; (3) Pumas do not select distinct habitats from those identified under hypothesis 1 when killing alternative prey. We found that pumas in our study selected for specific habitats and habitat features in general, but that their selection was more pronounced when killing black‐tailed deer. In summer, kill sites of deer were associated with rugged terrain, but gentle slopes and northerly aspects. In winter, pumas killed deer at low elevations, on gentle slopes and on northerly and westerly aspects. Overall, evidence suggested that pumas tracked their primary prey across seasonal migrations, which were short in distance but resulted in pronounced changes in elevation. When killing alternative prey, pumas showed little evidence of habitat selection, suggesting they may kill alternative prey opportunistically. Our results hold implications for how data should be partitioned when modelling baseline habitat selection of predators, hunting habitat selection and predation risk for prey species, as well as for how we model ecological processes such as apparent competition.
Summary Seabirds are highly threatened, including by fisheries bycatch. Accurate understanding of offshore distribution of seabirds is crucial to address this threat. Tracking technologies revolutionised insights into seabird distributions but tracking data may contain a variety of biases. We tracked two threatened seabirds (Salvin’s Albatross Thalassarche salvini n = 60 and Black Petrel Procellaria parkinsoni n = 46) from their breeding colonies in Aotearoa (New Zealand) to their non-breeding grounds in South America, including Peru, while simultaneously completing seven surveys in Peruvian waters. We then used species distribution models to predict occurrence and distribution using either data source alone, and both data sources combined. Results showed seasonal differences between estimates of occurrence and distribution when using data sources independently. Combining data resulted in more balanced insights into occurrence and distributions, and reduced uncertainty. Most notably, both species were predicted to occur in Peruvian waters during all four annual quarters: the northern Humboldt upwelling system for Salvin’s Albatross and northern continental shelf waters for Black Petrels. Our results highlighted that relying on a single data source may introduce biases into distribution estimates. Our tracking data might have contained ontological and/or colony-related biases (e.g. only breeding adults from one colony were tracked), while our survey data might have contained spatiotemporal biases (e.g. surveys were limited to waters <200 nm from the coast). We recommend combining data sources wherever possible to refine predictions of species distributions, which ultimately will improve fisheries bycatch management through better spatiotemporal understanding of risks.
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