Disturbance, Predation Risk, and Social Environment Create Predictable Spatial Patterns in Animal Foraging Behavior and Trophic Interactions

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
Genre:
ISBN:

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.

Foraging

Foraging
Author: David W. Stephens
Publisher: University of Chicago Press
Total Pages: 626
Release: 2008-09-15
Genre: Science
ISBN: 0226772659

Foraging is fundamental to animal survival and reproduction, yet it is much more than a simple matter of finding food; it is a biological imperative. Animals must find and consume resources to succeed, and they make extraordinary efforts to do so. For instance, pythons rarely eat, but when they do, their meals are large—as much as 60 percent larger than their own bodies. The snake’s digestive system is normally dormant, but during digestion metabolic rates can increase fortyfold. A python digesting quietly on the forest floor has the metabolic rate of thoroughbred in a dead heat. This and related foraging processes have broad applications in ecology, cognitive science, anthropology, and conservation biology—and they can be further extrapolated in economics, neurobiology, and computer science. Foraging is the first comprehensive review of the topic in more than twenty years. A monumental undertaking, this volume brings together twenty-two experts from throughout the field to offer the latest on the mechanics of foraging, modern foraging theory, and foraging ecology. The fourteen essays cover all the relevant issues, including cognition, individual behavior, caching behavior, parental behavior, antipredator behavior, social behavior, population and community ecology, herbivory, and conservation. Considering a wide range of taxa, from birds to mammals to amphibians, Foraging will be the definitive guide to the field.

Antipredator Defenses in Birds and Mammals

Antipredator Defenses in Birds and Mammals
Author: Timothy M. Caro
Publisher: University of Chicago Press
Total Pages: 609
Release: 2005-09
Genre: Nature
ISBN: 0226094367

Tim Caro explores the many & varied ways in which prey species have evolved defensive characteristics and behaviour to confuse, outperform or outwit their predators, from the camoflaged coat of the giraffe to the extraordinary way in which South American sealions ward off the attacks of killer whales.

Examining how Spatial-temporal Interactions Between Predators Influence the Distribution, Vigilance, and Survival of White-tailed Deer (Odocoileus Virginianus) Fawns

Examining how Spatial-temporal Interactions Between Predators Influence the Distribution, Vigilance, and Survival of White-tailed Deer (Odocoileus Virginianus) Fawns
Author: Asia Murphy
Publisher:
Total Pages:
Release: 2021
Genre:
ISBN:

Predator-prey interactions are among one of the most important community-structuring interspecific relationships. It is well known that predators have direct (i.e., consumptive) effects (CEs), influencing population density [1] and survival [2, 3], and indirect (i.e., non-consumptive) effects (NCEs) on prey. Typically, NCEs are caused by the prey's antipredator behaviors, and can range from changes in distribution and habitat use [4-8] to changes in morphology [9] and decreased reproductive success and recruitment [10-13] to increased vigilance and group size [14, 15]. Based on their strength, CEs and NCEs can scale up to affecting entire ecosystems through trophic cascades [16, 17]. Antipredator behaviors are often tied to the prey's perception of predation risk, which is the probability of prey encountering a predator and/or being killed [7] and varies across space and time [18, 19]. Prey perception of predation risk is based on predator identity and hunting style [20-23], and prey often connect the risk of being killed by an ambush predator to specific habitat features [4], while the risk of being killed by a wide-ranging predator is often not tied to habitat features [17], although these types of predators might find more success in open habitats [24]. This suggests that prey will use different antipredator strategies to avoid different predators. Whereas prey might avoid risky habitats when avoiding ambush predators, prey might avoid being active and/or increase vigilance during risky hours when coursing predators might be active and hunting [25]. While many studies focus on the effect of a single predator on prey [i.e., 8], in most ecological communities, there are often multiple predators preying on the same species [26-28]. The number of predatory species in an ecological community can influence the strength of predator effects on prey [27, 29]. If the antipredator strategies that prey use to reduce predation risk by one predator indirectly increases its chance of being killed by another predator [i.e., predator faciliation; 30], predators can more effectively suppress prey populations [29, 31]. Prey in multi-predator systems often seem unable to completely avoid all predators, and instead focus their energies on using antipredator behaviors meant to avoid predators in order of lethality [32]. The interactions between predators, and the interactions between predators and humans, can also influence predation pressure on prey [33]. A comprehensive study on antipredator behavior and survival in a multi-predator system would determine not only the spatiotemporal distributions, antipredator behavior, and survival probability of the prey, but the spatiotemporal distributions of the predators. The white-tailed deer (Odocoileus virginianus) are culturally and economically important species across much of the United States [34] in Pennsylvania. The number one cause of mortality in white-tailed deer fawns is predation [3, 35]; in Pennsylvania, black bears (Ursus americanus), coyotes (Canis latrans), and bobcats (Lynx rufus; Vreeland et al. 2004, McLean et al. 2005) are all known to prey on fawns. All three predators use different habitats [37-39], can be active at different times [40-42], and have different hunting styles [43, 44], creating a landscape of predation risk that varies spatially and temporally [45]. In addition, these predators--particularly coyotes and bobcats [46-48]--can compete with and influence the habitat use and activity patterns of the other predators, further complicating the landscape that fawns must navigate to survive. While this landscape of multi-predator predation risk has been characterized before for white-tailed deer fawns [see 49, 50], no one has attempted to do so in Pennsylvania. In this dissertation, I examine how habitat relationships (Chapter 1) and spatiotemporal interactions of and between humans, fawns, black bears, coyotes, and bobcats influence the vigilance (Chapter 2) and survival (Chapter 3) of fawns during their first three months of life. In Chapter 1, I find that differing matrix types can influence the similarity of coyote and fawn habitat use. In Chapter 2, I posit that the risk allocation hypothesis can explain why a number of studies--including my own--have found that, in more anthropogenically disturbed habitats, species that would normally avoid spatiotemporal overlap with each other increase in spatiotemporal overlap. In Chapter 3, I estimate fawn survival, examine its relationship to fawn antipredator behavior and habitat, and find that data from camera trap surveys could be a feasible alternative to radio-collaring when the goal is to estimate fawn survival. My research provides new insights into species interactions are influenced by anthropogenic disturbance and a template for noninvasively and inexpensively examining these interactions.

Social Foraging Theory

Social Foraging Theory
Author: Luc-Alain Giraldeau
Publisher: Princeton University Press
Total Pages: 379
Release: 2018-06-05
Genre: Science
ISBN: 0691188343

Although there is extensive literature in the field of behavioral ecology that attempts to explain foraging of individuals, social foraging--the ways in which animals search and compete for food in groups--has been relatively neglected. This book redresses that situation by providing both a synthesis of the existing literature and a new theory of social foraging. Giraldeau and Caraco develop models informed by game theory that offer a new framework for analysis. Social Foraging Theory contains the most comprehensive theoretical approach to its subject, coupled with quantitative methods that will underpin future work in the field. The new models and approaches that are outlined here will encourage new research directions and applications. To date, the analysis of social foraging has lacked unifying themes, clear recognition of the problems inherent in the study of social foraging, and consistent interaction between theory and experiments. This book identifies social foraging as an economic interaction between the actions of individuals and those of other foragers. This interdependence raises complex questions about the size of foraging groups, the diversity of resources used, and the propensity of group members to exploit each other or forage cooperatively. The models developed in the book will allow researchers to test their own approaches and predictions. Many years in development, Social Foraging Theory will interest researchers and graduate students in such areas as behavioral ecology, population ecology, evolutionary biology, and wildlife management.

Foraging Behavior

Foraging Behavior
Author: A.C. Kamil
Publisher: Springer Science & Business Media
Total Pages: 671
Release: 2012-12-06
Genre: Science
ISBN: 1461318394

Foraging behavior has always been a central concern of ecology. Understanding what animals eat is clearly an essential component of under standing many ecological issues including energy flow, competition and adaptation. Theoretical and empirical developments in the late 1960's and 1970's led to a new emphasis in the study of foraging behavior, the study of individual animals in both field and laboratory. This development, in turn, led to an explosion of interest in foraging. Part of the reason for this explosion is that when foraging is studied at the individual level, it is relevant to many disciplines. Behaviorists, including ethologists and psychologists, are interested in any attempt to understand behavior. Ecologists know that a better understanding of foraging will contribute to resolving a number of important ecological issues. Anthropologists and others are applying the ideas coming out of the study of foraging behavior to problems within their disciplines. These developments led to a multidisciplinary symposium on foraging behavior, held as part of the 1978 Animal Behavior Society meetings in Seattle, Washington. Many ecologists, ethologists and psychologists participated or attended. The symposium was very successful. generating a high level of excitement. As a result, the participants decided to publish the proceedings of the symposium (Kami1 & Sargent 1981).

Eat Or be Eaten

Eat Or be Eaten
Author: Lynne E. Miller
Publisher: Cambridge University Press
Total Pages: 298
Release: 2002-04-04
Genre: Nature
ISBN: 9780521011044

Edited work on behavioural strategies of primates in foraging for food, and avoiding being eaten.

Foraging Theory

Foraging Theory
Author: David W. Stephens
Publisher: Princeton University Press
Total Pages: 262
Release: 1986
Genre: Science
ISBN: 0691084424

This account of the current state of foraging theory is also a valuable description of the use of optimality theory in behavioral ecology in general. Organizing and introducing the main research themes in economic analyses of animal feeding behavior, the authors analyze the empirical evidence bearing on foraging models and answer criticisms of optimality modeling. They explain the rationale for applying optimality models to the strategies and mechanics of foraging and present the basic "average-rate maximizing" models and their extensions. The work discusses new directions in foraging research: incorporating incomplete information and risk-sensitive behavior in foraging models; analyzing trade-offs, such as nutrient requirements and the threat of being eaten while foraging; formulating dynamic models; and building constrained optimization models that assume that foragers can use only simple "rules of thumb." As an analysis of these and earlier research developments and as a contribution to debates about the role of theory in evolutionary biology. Foraging Theory will appeal to a wide range of readers, from students to research professionals, in behavioral ecology, population and community ecology, animal behavior, and animal psychology, and especially to those planning empirical tests of foraging models.

Foraging in Patches

Foraging in Patches
Author: Julie Ann Hart
Publisher:
Total Pages: 102
Release: 1997
Genre: Animal behavior
ISBN:

An experiment combining a simulated natural foraging environment with controlled exposure to a predator was conducted to explore how the efficiency of animals' foraging behavior may be consistent with an awareness of risk. Domestic pigeons, Columba livia, foraged in an indoor area with food in four patches. After 24 days of being risk free, the foraging area suddenly became risky by the introduction of a tethered domestic cat. The food-seeking behavior of the pigeons after the presence of the predator was compared to their behavior before the occurrence of the predator to evaluate how well the behavior in both phases matched that predicted by Optimal Foraging Theory. Pigeons showed sensitivity to the varying food densities available in the patches as well as the risk shift caused by the introduction of the predator. Sensitivity to risk was evidenced by the increased density of the food left in each patch, the increased time spent in all patches, and the increased frequency with which the birds moved between the patches in the post-predator phase.

The Spatial Ecology of Predator-Prey Interactions: A Case Study of Yellowstone Elk, Wolves, and Cougars

The Spatial Ecology of Predator-Prey Interactions: A Case Study of Yellowstone Elk, Wolves, and Cougars
Author: Michel T. Kohl
Publisher:
Total Pages: 187
Release: 2019
Genre:
ISBN:

Predators can serve as an important top-down driver of ecosystems via their influence on prey behavior. Although predator effects on prey behavior (or traits) may be as strong as or stronger than predator effects on prey abundance in small-scale, experimental systems, it is unclear whether behavioral effects are as dominant in large-scale, free-living systems. The objective of this project was to improve our ecological understanding of the spatio-temporal interactions between large predators and their primary prey source in a free-living system. Specifically, I used data from northern Yellowstone to evaluate 1) the role of predator diel activity on prey habitat selection of risky places, 2) how prey operate in a landscape composed of multiple predators that occupy different spatial and temporal niches, and 3) how the density - and behaviorally-meditated effects of large predators influence the large-scale spatial distribution of a prey population. In Chapter 2, I show that the predictability of daily wolf (Canis lupus) hunting activity provided an opportunity for elk (Cervus elaphus) to use risky places during safe times, which in essence, flattened (i.e., minimized) the landscape of fear in Yellowstone. In Chapter 3, I show that wolves and cougars (Puma concolor) hunt in different places, and at different times, which provided a refugia from these predators in time and space that likely minimized overall predation risk in an environment that was spatially saturated with wolves and cougars. In Chapter 4, I show that the current spatial distribution of elk across the northern range of Yellowstone is driven primarily by demographic rather than behavioral mechanisms. Overall, the results from chapters 2-4 suggest that any trophic cascade from predators, to prey, to deciduous woody plants in Yellowstone National Park is likely due to demographic mechanisms rather than a landscape of fear. More broadly, this research identifies a previously overlooked behavioral trait of predators, diel activity, which prey can use to minimize the effect of predators on sophisticated prey. Together, this study advances the field of ecology by quantifying the ecological importance of fear in a large-scale, free-living system.