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Full-Text Articles in Life Sciences
Environmental Variation, Stochastic Extinction, And Competitive Coexistence, Peter B. Adler, John M. Drake
Environmental Variation, Stochastic Extinction, And Competitive Coexistence, Peter B. Adler, John M. Drake
Wildland Resources Faculty Publications
Understanding how environmental fluctuations affect population persistence is essential for predicting the ecological impacts of expected future increases in climate variability. However, two bodies of theory make opposite predictions about the effect of environmental variation on persistence. Single‐species theory, common in conservation biology and population viability analyses, suggests that environmental variation increases the risk of stochastic extinction. By contrast, coexistence theory has shown that environmental variation can buffer inferior competitors against competitive exclusion through a storage effect. We reconcile these two perspectives by showing that in the presence of demographic stochasticity, environmental variation can increase the chance of extinction while …
Chihuahuan Desertkangaroo Rats: Nonlinear Effects Of Population Dynamics, Competition, And Rainfall, M. Lima, S.K. Morgan Ernest, J. H. Brown, A. Belgrano, N. C. Stenseth
Chihuahuan Desertkangaroo Rats: Nonlinear Effects Of Population Dynamics, Competition, And Rainfall, M. Lima, S.K. Morgan Ernest, J. H. Brown, A. Belgrano, N. C. Stenseth
Biology Faculty Publications
Using long-term data on two kangaroo rats in the Chihuahuan Desert of North America, we fitted logistic models including the exogenous effects of seasonal rainfall patterns. Our aim was to test the effects of intraspecific interactions and seasonal rainfall in explaining and predicting the numerical fluctuations of these two kangaroo rats. We found that logistic models fit both data sets quite well; Dipodomys merriami showed lower maximum per capita growth rates than Dipodomys ordii, and in both cases logistic models were nonlinear. Summer rainfall appears to be the most important exogenous effect for both rodent populations; models including this variable …