Toward an Integration of Landscape and Food Web Ecology: The Dynamics of Spatially Subsidized Food Webs

TLDR

Movement of nutrients, detritus, prey, and consumers across habitats creates spatial subsidies that can alter primary and secondary productivity, predator abundance, and trophic cascades, with effects modulated by subsidy magnitude, trophic roles, local food‑web structure, and landscape characteristics such as habitat perimeter/area ratio and boundary permeability. The study investigates how movement, landscape variables, and spatial heterogeneity influence food‑web dynamics.

Abstract

We focus on the implications of movement, landscape variables, and spatial heterogeneity for food web dynamics. Movements of nutrients, detritus, prey, and consumers among habitats are ubiquitous in diverse biomes and can strongly influence population, consumer-resource, food web, and community dynamics. Nutrient and detrital subsidies usually increase primary and secondary productivity, both directly and indirectly. Prey subsidies, by movement of either prey or predators, usually enhance predator abundance beyond what local resources can support. Top-down effects occur when spatially subsidized consumers affect local resources by suppressing key resources and occasionally by initiating trophic cascades. Effects on community dynamics vary with the relative amount of input, the trophic roles of the mobile and recipient entities, and the local food web structure. Landscape variables such as the perimeter/area ratio of the focal habitat, permeability of habitat boundaries, and relative productivity of trophically connected habitats affect the degree and importance of spatial subsidization.