Scaling from plot experiments to landscapes: studying grasshoppers to inform forest ecosystem management.
Ecologists studying food web interactions routinely conduct their experiments at scales of 1-10 m(2) whereas real-world landscape-level management problems exist on scales of 10(6) m(2) or larger. It is often asserted that the experimental tradition in ecology has little to offer to environmental management because small scale empirical insights are not easily, if at all, translatable to the large scale problems. Small scale experiments are very local in nature and they are conducted in ways that tend to homogenize background environmental variation. Real world management is conducted across vast landscapes. Managers routinely must wrestle with complexity that is introduced by the heterogeneous structure of those landscapes and they often have limited recourse to do careful experimentation. How then is empirical ecological science ever to inform landscape-level management? The solution to this dilemma lies in arriving at good working conceptualizations of ecosystem structure and function that embody principles that are relatively scale independent. In this paper, the evolutionary ecological principle of foraging versus predation risk avoidance trade-offs is proffered as one central organizing conceptualization for plant-herbivore interactions across all systems. The utility of this conceptualization is first illustrated by presenting results of detailed experiments involving spider predators, grasshopper herbivores, and two classes of plant resources that afford grasshoppers differential protection from predators: nutritionally superior but risky grasses and less nutritious but safer herbs. The paper then shows how the foraging versus predation risk avoidance conceptualization in the context of a "landscape of fear" can be applied to manage large herbivore impacts of forest regeneration following forest harvesting. I present results of landscape-scale experiments that mediate predation risk of the herbivores through manipulation of safe habitat in order to enlist herbivores to facilitate boreal forest mixed species regeneration through preferential foraging of certain woody species.
Schmitz
Oswald J
OJ
School of Forestry and Environmental Studies and Department of Ecology and Evolutionary Biology, Yale University, 370 Prospect Street, New Haven, CT 06511, USA. oswald.schmitz@yale.edu
D000818:Animals; D044822:Biodiversity; D003670:Deer / Q000502:physiology; D004463:Ecology / Q000379:methods*; D017753:Ecosystem; D005247:Feeding Behavior; D020387:Food Chain; D006110:Grasshoppers / Q000502:physiology*; D034621:Hares / Q000502:physiology; D008954:Models, Biological; D009511:New England; D028222:Picea / Q000502:physiology; D032107:Populus / Q000502:physiology; D014197:Trees / Q000502:physiology