Critical slowing down as a leading indicator of regime shift in the paradox of enrichment
Complex Systems Laboratory, University of Montreal
Last modified: September 27, 2007
Regime shifts in ecological systems are characterised by abrupt transitions between alternative persistent states. The “ecological resilience” of such systems is the size of the basin of attraction around stable states. Recent research has demonstrated that a system’s rate of recovery from small perturbations is a good indicator of ecological resilience. The decrease in recovery rate as an ecosystem approaches a regime shift is termed “critical slowing down.” Here we investigate the conditions under which critical slowing down providers an early indicator of regime shift in a classic ecological model: “the paradox of enrichment.” We find that critical slowing down provides an earlier indicator of regime shift in simple predator-prey systems where: (1) the prey population growth rate is low; (2) the predation rate is high; and/or (3) predator-prey biomass conversion is efficient. If confirmed for more complicated, realistic models, these results will help identify real ecosystems in which critical slowing down is a useful indicator of regime shift.