Scale dependency and functional response in moose habitat selection

Abstract

Habitat selection can be influenced by the distribution of the habitat types in the landscape as well as net gain in visiting patches of resources, causing individual variation in habitat selection. Moreover, the hypothesis of functional response in habitat selection predicts that the degree of selection of a resource depends on its relative availability. We used radio-telemetry data from individual moose on an island off the coast of northern Norway to evaluate whether the selection of habitat types at the landscape scale differed from the choice of habitat types within the home range, and investigated the functional response in habitat selection by relating individual habitat selection to home range characteristics. At the landscape scale, moose selected for habitat types that provided both good forage and cover, with small differences between sex and age groups. At the home range scale, all individuals selected habitat types that were associated with cover and low human impact. Habitat selection was not modified by local moose density, but was related to home range size at both spatial scales. Larger home ranges contained larger proportions of non-preferred habitat types compared to smaller home ranges. At the home range scale, the selection for a habitat type decreased with its relative availability, indicating a functional response in habitat selection. This suggests that habitat selection is modified by home range size, which influences the availability of habitat types and shapes individual habitat selection patterns. Our results support previous suggestions that analyses of habitat or resource selection should follow a multiscale approach. Both the relative availability of habitat types as well as individual variation in home range size should be accounted for in order to disentangle the complex mechanisms that contribute to shape patterns of resource selection in animals.

Coupling scale-specific habitat selection and activity reveals sex-specific food/cover trade-offs in a large herbivore

“…The highest risk is during the hunting period, when food abundance and quality are low and the weather is generally inclement. We hence expected that the main habitats selected during this period should correspond to areas perceived as safe at all scales, for both males and females and irrespective of the activity level (Dussault et al, 2005;Herfindal et al, 2009;. Even though food resources are senescent, autumn forage contributes to improving body condition before winter in large herbivores (Hurley et al, 2014), so that the baseline expectation in the absence of hunting would have been a selection for foraging areas.…”

Evaluating the landscape of fear between apex predatory sharks and mobile sea turtles across a large dynamic seascape

“…For example, roe deer (Capreolus capreolus) in southern Norway do not shift habitat use in response to predation risk during winter because they are constrained by other factors such as thermoregulation and starvation due to food limitation (Ratikainen et al 2007, Lone et al 2014. Determining optimal strategies in light of different trade-offs can be particularly challenging for highly mobile species that move across dynamic landscapes (Herfindal et al 2009, Beauchesne et al 2013. However, there is a general paucity of studies that have tested the landscape of fear model across dynamic environments involving highly migratory species at large spatial scales (tens to hundreds of thousands of square kilometers), probably due to logistical and technological challenges of working in such systems, particularly in open aquatic systems.…”

Home ranges, habitat and body mass: simple correlates of home range size in ungulates

“…Individuals' movement decisions affect what they can eat [1,2], who they get eaten by [3,4] and who they can mate with [5,6]. The pattern of movement may therefore strongly influence individual differences in fitness [7] and hence generate spatio-temporal variation in population dynamics [8][9][10].…”