Population synchrony and environmental variation: an experimental demonstration
Understanding mechanisms that facilitate metapopulation synchrony is important due to the increased risk of metapoulation extinction associated with more synchronous populations. Currently, we understand two factors that can lead to increased synchrony, dispersal, and extrinsic noise. Where extrinsic noise can be considered environmental conditions. Provided these two factors, the authors in this paper sought to understand the effects of environmental conditions on synchrony by limiting patch dispersal.
Populations of the soil mite, Sancassania berlesei, where collected and placed into 5 test tubes with the necessary reagents for population growth. Tubes were not connected which prevented any confounding effects of dispersal. Environmental variation was manipulated by varying the amount of food provided to each test tube.
When then environment is not varied, populations exhibited dampening oscillations. Indicating a weak effect of density dependence. For varied environmental conditions, researchers observed a significant positive correlation between population synchrony and environmental conditions. However, this observation is dependent on the life stage of the organisms.