Disturbance, Predation Risk, and Social Environment Create Predictable Spatial Patterns in Animal Foraging Behavior and Trophic Interactions
Author | : Savannah Lynn Bartel |
Publisher | : |
Total Pages | : 0 |
Release | : 2022 |
ISBN-10 | : OCLC:1350794687 |
ISBN-13 | : |
Rating | : 4/5 ( Downloads) |
Download or read book Disturbance, Predation Risk, and Social Environment Create Predictable Spatial Patterns in Animal Foraging Behavior and Trophic Interactions written by Savannah Lynn Bartel and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Animal foraging behavior not only affects individual fitness of animals but can also mediate the magnitude of granivory and herbivory of plant communities. As a result, understanding how aspects of the environment affect animal foraging behavior is critical to predicting how changes in the environment may directly affect animal populations and indirectly affect plant communities. Since animals must avoid attack by predators or costly encounters with conspecific competitors while foraging, animal behavior may be shaped by characteristics of the environment that predict the likelihood of predation or intraspecific competition. Disturbances, such as fire and forest harvest, can have profound impacts on habitat characteristics (e.g., vegetative concealment from predators) that affect the identity and behavior of animals foraging in a habitat. Moreover, the legacies of historic disturbances, like past agricultural land use in restored habitats, can also impact habitat structure and, as a consequence, animal foraging behavior. By conducting an experiment that coupled canopy harvesting at sites containing both post-agricultural land use and nonagricultural land use, I found that land-use history and canopy harvesting determine the outcomes of seed-granivore interactions by modifying environmental characteristics relevant to mammal behavior. Seed predation rates in harvested plots were positively correlated with cotton rat (Sigmodon hispidus) foraging activity, which was lower in post-agricultural harvested plots than in nonagricultural harvested plots. In unharvested plots, seed predation increased with fox squirrel (Sciurus niger) activity, but fox squirrels were not affected by land-use history. In another experiment that measured white-tailed deer (Odocoileus virginianus) foraging and antipredator behavior across longleaf pine woodlands varying in past land use and contemporary fire frequency, I found that frequent fires generated riskier habitats for deer, but deer utilized different antipredator strategies while foraging in habitats with different land-use histories. Experimental manipulation of acoustic predator cues (i.e., coyote (Canis latrans) vocalizations) revealed that deer only modify their foraging behavior in response to a direct cue of predator activity in frequently burned, nonagricultural woodlands. Long-term herbivore exclosures revealed that deer herbivory only reduced deer-preferred plant species richness in infrequently burned woodlands, where deer perceptions of risk were lower. These results suggest that past and present disturbances can interact to generate "landscapes of fear" in which spatial variation in deer antipredator behavior may help explain large-scale patterns in plant communities. Omnivorous predators, such as coyotes, that consume both animal prey and fleshy fruits may also affect plant communities as agents of seed dispersal. Since coyote foraging decisions determine individual diet and space use, understanding how aspects of the environment affect individual coyote foraging decisions is essential to understanding how environmental changes may affect seed dispersal by coyotes. By experimentally manipulating seed association with coyote scat and granivore access to seeds, I found that seed dispersal in coyote scat reduced predation of larger seeds by rodents but increased predation of smaller seeds by arthropods. Coyote scat composition was also important in affecting rodent seed predation such that seed predation was lower in the presence of meat-rich scat compared with fruit-rich scat. These results illustrate that individual coyote foraging decisions can have cascading effects on seed dispersal and survival. In an experiment evaluating how time of day and conspecific activity affect coyote foraging decisions, I found that coyotes were more likely to investigate experimental resource patches towards the end of the diel activity period and were less likely to consume resources at patches that were visited by other conspecifics. Collectively, these studies illustrate that individual coyote foraging decisions may plan an important role in mediating seed dispersal and survival, and coyote foraging decisions may be shaped by an individual's social environment.