PARENT SESSION
Oral Session #4: Animal Population Ecology.
Presiding: L. Mitchell
Monday, August 5. 8:00 AM to 11:30 AM. Gila Meeting Room, TCC.

Cycles and synchrony: an experimental evaluation with replicated populations.

BECKERMAN, ANDREW^*,1, BENTON, TIM¹, LAPSLEY, CRAIG¹, ¹ Univeristy of Stirling, Stirling, United Kingdom

ABSTRACT- Fluctuations in animal numbers that occur synchronously among populations have fascinated ecologists for centuries. The Moran effect, a key hypothesis about synchrony, poses that if populations share the same density dependent structure, common environmental variation can synchronise dynamics. The Moran effect has never before been assessed in replicated populations with known stochastic variation. Here we report on replicated, population level, population dynamic experiments where stochastic environmental variation was manipulated across mite (Sancassania berlesei) populations and their dynamics and synchrony analysed. First, due to small differences in age structure among populations and individual plasticity in the life history, we found that common environmental variation never generated population correlations at the same level as the input environmental correlation. Second, we found that the stage or age class being measured had a significant effect on the measure of synchrony. Thirdly, we found that the underlying population dynamic attractor, e.g. steady state versus cycles, influenced the measure of synchrony. Our study confirms some previous observations about synchrony made on unreplicated, wild populations and highlights the need to investigate the interactions between density dependence, life history plasticity, age structure and population dynamics in experimental systems.

KEY WORDS: Population dynamics, Moran Effect, Synchrony