Size-dependent life-history traits promote catastrophic collapses of top predators

Authored by L Persson, Roos AM de

Date Published: 2002

DOI: 10.1073/pnas.192174199

Sponsors: Netherlands Organization for Scientific Research (NWO) Swedish Research Council Swedish Council for Forestry and Agricultural Research (SJFR)

Platforms: No platforms listed

Model Documentation: Other Narrative Mathematical description

Model Code URLs: Model code not found

Abstract

Catastrophic population collapses such as observed in many exploited fish populations have been argued to result from depensatory growth mechanisms (i.e., reduced reproductive success at low population densities, also known as Allee effect). Empirical support for depensation from population-level data is, however, hard to obtain and inconclusive. Using a size-structured, individual-based model we show that catastrophic population collapses may nonetheless be an intrinsic property of many communities, because of two general aspects of individual life history: size- and food-dependent individual growth and individual mortality decreasing with body size. Positive density dependence, characteristic for depensatory growth mechanisms and catastrophic behavior, results as a direct and robust consequence of the interplay between these individual life-history traits, which are commonly found in many species.

Tags

Dynamics ecosystems ecology patterns Survival Recovery Population consequences Fish stocks