Allometry and catastrophic regime shifts in food chains.
Population dynamics can reflect the body mass distribution of species because there is an allometric relationship between the average body mass of species and its metabolic timescale. Since predators are generally larger than their prey, a hierarchical structure from fast timescales to slow timescales can be a general structure in food webs. In this paper, we show that changes of the metabolic timescale ratio can cause catastrophic shifts. Then, we investigate a two-dimensional parameter space with the timescale ratio and the carrying capacity of basal species, and reveal that the timescale ratio characterizes the response of the system to environmental variation. Finally, in a bistable regime, we try to clarify the relationship between the trophic position of a species and the extent to which the species induces attractor switching. We saw that, in a 4-species food chain, top predators and second consumers induce attractor switching easily compared to first consumers and basal species.
Suzuki
Kenta
K
Department of General Systems Studies, The Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Tokyo 153-8902, Japan. kens@sacral.c.u-tokyo.ac.jp
Ikegami
Takashi
T
D000818:Animals; D001835:Body Weight; D004777:Environment; D020387:Food Chain; D008660:Metabolism; D011157:Population Dynamics; D011235:Predatory Behavior; D013045:Species Specificity