Animals disperse in response to poor resource conditions as a strategy of escaping harsh competition and stress, but may also disperse under good resource conditions, as these provide better chances of surviving dispersal and gaining fitness benefits such as avoiding kin competition and inbreeding. Individual traits should mediate the effect of resources, yielding a complex condition-dependent dispersal response. We investigated how experimental food reductions in a food-rich environment around poultry-growing villages interact with individual-traits (age, gender, body-mass) in two sympatric canids, red foxes and golden jackals, to jointly affect emigration propensity and survival during dispersal. Sub-adult foxes emigrated more frequently from the food-rich habitat than from the pristine, food-limited habitat, while adult foxes showed the opposite trend. During dispersal, adults exhibited lower survival while sub-adults did not experience additional mortality costs. Although fox mortality rates increased in response to food reduction, dispersal remained unchanged, while jackals showed strong dispersal response in two of the three repetitions. Jackal survival under food reduction was lowest for the dispersing individuals. While resources are an important dispersal determinant, different age classes and species experience the same resource environment differently and consequently have different motivations, yielding different dispersal responses and consequences.

The residence time is the amount of time spent within a predefined circle surrounding each point along the movement path of an animal, reflecting its response to resource availability/quality. Two main residence time‐based methods exist in the literature: (1) The variance of residence times along the path plotted against the radius of the circle was suggested to indicate the scale at which the animal perceives its resources; and (2) segments of the path with homogeneous residence times were suggested to indicate distinct behavioral modes, at a certain scale. Here, we modify and integrate these two methods to one framework with two steps of analysis: (1) identifying several distinct, nested scales of area‐restricted search (ARS), providing an indication of how animals view complex resource landscapes, and also the resolutions at which the analysis should proceed; and (2) identifying places which the animal revisits multiple times and performs ARS; for these, we extract two scale‐dependent statistical measures—the mean visit duration and the number of revisits in each place. The association between these measures is suggested as a signature of how animals utilize different habitats or resource types. The framework is validated through computer simulations combining different movement strategies and resource maps. We suggest that the framework provides information that is especially relevant when interpreting movement data in light of optimal behavior models, and which would have remained uncovered by either coarser or finer analyses.

While road-side productivity attracts wildlife, roads are also a major cause of mortality. Thus, roads are potentially an attractive sink. We investigated whether roads in a desert environment in southern Israel act as an ecological trap for the territorial mourning wheatear (Oenanthe lugens). We applied an individual-based mechanistic approach to compare the apparent survival of individually-marked wheatears between roadside territories and territories in natural habitats farther away from the road, and determined directionality in territorial shifting to and from the road. Analysis was based on mark-resight techniques and multi-model inference in a multi-strata approach (program MARK). Wheatear survival in road-side territories was too low to be compensated by the maximum possible recruitment, but shifted territories from natural habitat toward the roadside habitat as these territories were vacated by mortality. Vacated territories along the road were re-occupied faster than vacated territories in natural habitat. Thus, the roadside habitat in our study area fulfilled all conditions for an ecological trap. Roads may act as widespread ecological traps and their impact, therefore, may extend well-beyond the existing perception of narrow dissecting elements causing local mortality and/or animal avoidance. In species where habitat selection is based on contest competition (e.g., territorial species) and contest success has a genetically heritable component, ecological traps will induce a paradoxical selection process.

Recruitment and adult‐mortality may respond differently to increased population density. Such unequal density dependence (UDD) is evident for large mammals showing density dependence mainly in recruitment (reproduction rate or juvenile survival), whereas adult survival is high and varies little with density. Mechanistically, UDD is likely influenced by an unequal allocation of resources toward reproduction versus survival. Unequal density dependence is expected to affect compensation abilities, and hence may have serious implications with regard to population harvesting. We modeled UDD by linking population size to reproduction and survival through per capita resource availability and consumption. We integrated UDD into 2 population models (continuous vs. periodic recruitment) and investigated how it affected the compensatory dynamics of populations. For a population with continuous recruitment, our model predicted that although UDD stabilizes the population dynamics, it makes populations more vulnerable to harvesting as a consequence of lower compensatory ability, regardless of whether more resources are allocated to reproduction or to survival. For populations with periodic recruitment, on the other hand, an asymmetric effect of UDD is predicted. Strong density dependence in recruitment relative to adult survival yields a strong compensatory response, whereas equal or stronger density dependence in adult survival relative to recruitment yields weaker compensatory responses. Stronger density dependence in recruitment also causes the periodic fluctuations in population size to be amplified rather than dampened under harvesting. These results are robust to alternative model formulations (e.g., Ricker and Beverton‐Holt equations). Using an empirical example for coyotes (Canis latrans), wild boars (Sus scrofa), and white‐tailed deer (Odocoileus virginianus), we demonstrated the implications of our results for harvest management of medium‐size mammalian species that are periodic breeders and exhibit density‐dependent recruitment. Accounting for UDD in the population model of coyotes and wild boars, which are characterized by large litters, predicts compensation that is stronger than the response obtained without UDD. For white‐tailed deer, which are characterized by substantially smaller litters, accounting for UDD does not change the outcome. Harvest‐based control attempts of medium‐size mammals may hence be much less effective than predicted when the population models used to estimate them ignore UDD, suggesting the necessity of integrating UDD into these models. © 2018 The Wildlife Society.

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