title: Spatial scaling of consumer-resource interactions in advection-dominated systems.
abstract: Ecologists studying consumer-resource interactions in advection-dominated systems such as streams and rivers frequently seek to link the results of small-scale experiments with larger-scale patterns of distribution and abundance. Accomplishing this goal requires determining the characteristic scale, termed the response length, at which there is a shift from local dynamics dominated by advective dispersal to larger-scale dynamics dominated by births and deaths. Here, we model the dynamics of consumer-resource systems in a spatially variable, advective environment and show how consumer-resource interactions alter the response length relative to its single-species value. For one case involving a grazer that emigrates in response to high predator density, we quantify the changes using published data from small-scale experiments on aquatic invertebrates. Using Fourier analysis, we describe the responses of advection-dominated consumer-resource systems to spatially extended environmental variability in a way that involves explicit consideration of the response length. The patterns we derive for different consumer-resource systems exhibit important similarities in how component populations respond to spatial environmental variability affecting dispersal as opposed to demographic parameters.
authors.affiliation: Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, California 93106, USA. kanderson@bio.fsu.edu
authors.forename: Kurt E
authors.initials: KE
authors.lastname: Anderson
authors.forename: Roger M
authors.initials: RM
authors.lastname: Nisbet
authors.forename: Sebastian
authors.initials: S
authors.lastname: Diehl
mesh_terms: D017753:Ecosystem; D008954:Models, Biological; D011157:Population Dynamics