Omnivory and food web dynamics
Kuijper, L. D., Kooi, B. W., Zonneveld, C. and Kooijman, S. A. L. M. 2003.
Omnivory and food web dynamics. Ecological Modelling 163: 19 - 32
Abstract
Intraguild predation is a trophic interaction in which two consumers
compete for one resource and where one of the consumer species may
also feed on its competitor. The intraguild predator s diet follows
from the relative strength of its interactions with its potential
prey. Current view holds that weak interactions between species
promote the stability of food webs. To the contrary, nutrient
enrichment is predicted to destabilize ecosystems. We present a
theoretical analysis of the interplay between intraguild predation and
nutrient enrichment in a Marr-Pirt chemostat model of a microbial food
web. We perform a two-dimensional bifurcation analysis along a
gradient of allochtonous nutrient levels and a gradient of one out of
two biologically plausible strategies to explore the spectrum of the
intraguild predator s foraging interactions. Both strategies show that
intraguild predation may stabilize food chains; eliminate chaos,
predicted by food chain models; give rise to multiple stable states;
be favored in systems with low turnover rates, where the intraguild
predator has a low interaction strength and a low yield on the basal
resource.