Effects of habitat quality and size on extinction in experimental populations
- 10 June 2008
- journal article
- Published by The Royal Society in Proceedings. Biological sciences
- Vol. 275 (1648), 2251-2256
- https://doi.org/10.1098/rspb.2008.0518
Abstract
Stochastic population theory makes clear predictions about the effects of reproductive potential and carrying capacity on characteristic time-scales of extinction. At the same time, the effects of habitat size and quality on reproduction and regulation have been hotly debated. To trace the causal relationships among these factors, we looked at the effects of habitat size and quality on extinction time in experimental populations of Daphnia magna. Replicate model systems representative of a broad-spectrum consumer foraging on a continuously supplied resource were established under crossed treatments of habitat size (two levels) and habitat quality (three levels) and monitored until eventual extinction of all populations. Using statistically derived estimates of key parameters, we related experimental treatments to persistence time through their effect on carrying capacity and the population growth rate. We found that carrying capacity and the intrinsic rate of increase were each influenced similarly by habitat size and quality, and that carrying capacity and the intrinsic rate of increase were in turn both correlated with time to population extinction. We expected habitat quality to have a greater influence on extinction. However, owing to an unexpected effect of habitat size on reproductive potential, habitat size and quality were similarly important for population persistence. These results support the idea that improving the population growth rate or carrying capacity will reduce extinction risk and demonstrate that both are possible by improving habitat quality or increasing habitat size.Keywords
This publication has 24 references indexed in Scilit:
- Environmental Variation, Stochastic Extinction, and Competitive CoexistenceThe American Naturalist, 2008
- Propagule pressure and persistence in experimental populationsBiology Letters, 2005
- Influence of habitat quantity, quality and isolation on the distribution and abundance of two epiphytic lichensJournal of Ecology, 2003
- Comparing Risk Factors for Population ExtinctionJournal of Theoretical Biology, 2000
- Global Biodiversity Scenarios for the Year 2100Science, 2000
- Effects of habitat size and quality on equilibrium density and extinction time of Sorex araneus populationsJournal of Animal Ecology, 1998
- Army ant population dynamics: the effects of habitat quality and reserve size on population size and time to extinctionProceedings. Biological sciences, 1996
- Spatial Structure and Population Extinction: A Study with Drosophila FliesConservation Biology, 1989
- Refuge Design and Island Biogeographic Theory: Effects of FragmentationThe American Naturalist, 1982
- The island dilemma: Lessons of modern biogeographic studies for the design of natural reservesBiological Conservation, 1975