It's the "Foodscape", not the Landscape: Using Foraging Behavior to Make Functional Assessments of Landscape Condition

Abstract

Foraging animals interact with their food resources in complex ways, both responding to and creating variation in resource quality, quantity, distribution, and structure. The reciprocity of this interaction means that the value of food resources at any given moment is a property of both the landscape and the foraging animal. Traditional approaches to assessing landscape condition for large herbivores have relied upon coarse measurements of vegetation properties such as biomass as though they are equally applicable to all herbivores in the system; however, because different herbivore species will have differences in the way they perceive vegetation, changes to the quantity and quality of vegetation in a landscape will be interpreted differently by different herbivore species. This variation means that vegetation measurements often fail to adequately capture the true value of a resource for a foraging animal. We advocate a new approach to assessing landscape conditions for large herbivores. It invokes the use of behavioral indicators to measure the value of "foodscapes" to foraging animals. Foodscapes are inherently animal-centric, and are defined by using foraging behavior to measure the value that an animal places on the vegetation within its environment. In effect, foodscapes define what the "resource" is to the animal. We demonstrate our approach by summarizing the behavioral responses of grazing ruminants to two very relevant drivers of ecosystem change, CO₂ enrichment and land-use change. We use these responses to develop a suite of behavioral indicators that are sufficient to detect critical changes in the value of the foodscape for grazing ruminants. Our analysis demonstrates the potential for using behavioral indicators to enable early detection of critical changes in forage value that would fail to be recognized by traditional approaches.

Keywords:

• behavioral indicators
• CO2 enrichment
• diet selection
• foodscape
• foraging behavior
• land-use change
• ruminants