Distribution and Movement Patterns of African Wild Dogs and Red Foxes in Relation to Habitat Structure and Anthropogenic Influence.

摘要

Diversity and spread of habitat types (i.e. heterogeneity) within a landscape have important implications for the distribution of resources (e.g. prey species) and subsequently the distribution and movement patterns of animals. Human activities often directly disrupt the natural environment, fragmenting it into patches of natural habitat interspersed with human-use areas that are not suitable for many animal species. Other phenomena, like climate change, can gradually change the structure of a landscape, resulting in changes in biological community structure. The study of animal movement through diverse and patchy landscapes can thus be a valuable tool for understanding the effects that human activities and natural change (e.g. weather patterns) can have on animals.;Radio-collared African wild dogs were tracked as a pack for 19 months in South Africa to provide locational fixes used in this study to examine home range and habitat selection over different seasons. Red foxes were snow-tracked for two winter seasons on Prince Edward Island (Canada) to obtain detailed movement paths, which were compared among geographically distinct study sites in terms of habitat selection, path shape, displacement, and interaction with local habitat variables such as snow depth. Mapping software was used to relate movement and distribution of both species to their respective habitat characteristics.;The African wild dog pack selected some habitats consistently, indicating some specialization, but the home-range size and location were inconsistent and extended to the reserve boundaries (and beyond on a number of occasions), suggesting that the enclosed area did not contain all the resources required by the pack. Simulated specialist movement path shape was affected by increasing fragmentation (decrease of good habitat), becoming straighter (or more directed) in less suitable habitats. Wild dogs, consistent with their status as specialist predators, showed some specialist tendencies in this study and extended their range beyond the reserve, similar to the way in which simulated specialists extended their paths directly through unsuitable habitat. Although red foxes had similar movement patterns at all study sites, habitat selection differed across study sites with few consistencies among sites that were more heterogeneous or human-impacted. Thus, fox movement does not appear to be impacted by fragmentation or heterogeneity. Foxes demonstrated versatility, which is consistent with a generalist definition. Simulated generalists, like the foxes studied here, were not affected by fragmentation as indicated by similar shape at all fragmentation levels (or percentages of good habitat). Fox movement had dispersal consistent with that expected from a Lévy walk model which is indicative of an optimal foraging strategy.;The primary goal of this research was to investigate the interaction of important predatory mammals with their environments using different techniques in order to discern potential anthropogenic effects on the species. Two species of mammalian predator, the African wild dog (Lycaon pictus) and the red fox (Vulpes vulpes) were examined. Movement data obtained from field studies were compared with predictions made from theoretical movement models. Computer simulations were performed using an individual-based movement model to explore fundamental movement patterns in fragmented landscapes and to permit some comparisons between the two species in light of the fact that the wild dog is considered a specialist (limited in landscape use by specific requirements) and the red fox, a generalist (flexible in landscape use).