7 - When sinks rescue sources in dynamic environments  pp. 139-154

When sinks rescue sources in dynamic environments

By Matthew R. Falcy and Brent J. Danielson

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Many species of conservation concern occur in spatially heterogeneous landscapes composed of different patches that function as population sources and population sinks. Temporal variation in habitat quality, due to a cycle of habitat disturbance and subsequent recovery, can create relatively underappreciated source–sink dynamics. A cycle of disturbance and recovery can cause a given patch to alternate between functioning as a population source and a population sink. During “good” years, this patch can conceivably sustain another nearby patch that is always sink habitat. However, after a disturbance, the putative source patch may then depend upon individuals from that sink for recolonization. Thus, the metapopulation can depend upon the presence of sink populations for long-term persistence, provided that the sink is relatively unaffected by disturbance. We developed a simple, two-patch model of source–sink dynamics in order to explore the sensitivity of long-term metapopulation persistence to the temporal scale of habitat disturbance, recovery in a putative source patch, and the rate of population decline in the sink. We found that management directed at decelerating the rate of population decline in the sink can have a much greater affect on metapopulation persistence than management targeted at increasing the rate of habitat recovery in the source. This result is magnified as disturbance frequency increases. It is hoped that sinks crucial to metapopulation survival are given appropriate conservation status.

Emanuel, K. (2005). Increasing destructiveness of tropical cyclones over the past 30 years. Nature 436(7051): 686–688.
Foppen, R. P. B. , J. P. Chardon and W. Liefveld (2001). Understanding the role of sink patches in source–sink metapopulations: reed warbler in an agricultural landscape. Conservation Biology 14(6): 1881–1892.
Gonzalez, A. and R. D. Holt (2002). The inflationary effects of environmental fluctuations in source–sink systems. Proceedings of the National Academy of Science 99(23): 14872–14877.
Gyllenberg, M. , A. V. Osipov and G. Södervacka (1996). Bifurcation analysis of a metapopulation model with sources and sinks. Nonlinear Science 6: 329–366.
Hey, J. (2006). On the failure of modern species concepts. Trends in Ecology and Evolution 21(8): 447–450.
Holt, R. D. (1985). Population dynamics in two-patch environments: some anomalous consequences of an optimal habitat distribution. Theoretical Population Biology 28: 181–208.
Holt, R. D. (1997). On the evolutionary stability of sink populations. Evolutionary Ecology 11: 723–731.
Holt, R. D. , M. Barfield and A. Gonzalez (2003). Impacts of environmental variability in open populations and communities: “inflation” in sink environments. Theoretical Population Biology 64: 315–330.
Howell, A. H. (1909). Notes on the distribution of certain mammals of the southeastern United States. Proceedings of the Biology Society of Washington 22: 55–68.
Howell, A. H. (1921). A biological survey of Alabama. North American Fauna 45: 1–88.
Ivey, R. D. (1949). Life history notes on three mice from the Florida east coast. Journal of Mammalogy 30: 157–162.
Jansen, V. A. A. and J. Yoshimura (1998). Populations can persist in an environment consisting of sink habitats only. Proceedings of the National Academy of Science 95: 3696–3698.
Johnson, D. (2004). Source–sink dynamics in a temporally heterogeneous environment. Ecology 85(7): 2037–2045.
Kingsland, S. E. (1995). Modeling Nature: Episodes in the History of Population Ecology. University of Chicago Press, Chicago, IL.
Landsea, C. (2005). Hurricanes and global warming. Nature 438: E11–E13.
Malanson, G. P. (1993). Riparian Landscapes. Cambridge University Press, New York.
Morris, D. W. (2003). Toward an ecological synthesis: a case for habitat selection. Oecologia 136: 1–13.
Morris, W. F. and D. F. Doak (2002). Quantitative Conservation Biology: Theory and Practice of Population Viability Analysis. Sinauer Associates, Sunderland, MA.
Pulliam, H. R. (1988). Sources, sinks, and population regulation. American Naturalist 132(5): 652–661.
Pulliam, H. R. (1996). Sources and sinks: empirical evidence and population consequences. In Population Dynamics in Ecological Space and Time ( O. E. Rhodes Jr., R. K. Chesser and M. H. Smith , eds.). University of Chicago Press, Chicago, IL: 45–70.
Roy, M. , R. D. Holt and M. Barfield (2005). Temporal autocorrelation can enhance the persistence and abundance of metapopulations comprised of coupled sinks. American Naturalist 166(2): 246–161.
Sneckenberger, S. I. (2001). Factors influencing habitat use by the Alabama beach mouse (Peromyscus polionotus ammobates). MS thesis, Auburn University, Auburn, AL.
Swilling, W. R. Jr., M. C. Wooten , N. R. Holler and W. J. Lynn (1998). Population dynamics of Alabama beach mouse (Peromyscus polionotus ammobates) following Hurricane Opal. American Midland Naturalist 140: 287–298.
Tilman, D. , R. M. May , C. L. Lehman and M. A. Nowak (1994). Habitat destruction and the extinction debt. Nature 371: 65–66.
Trenberth, K. (2005). Uncertainty in hurricanes and global warming. Science 308(5729): 1753–1754.
USFWS (US Fish and Wildlife Service) (2005). Draft Revised Habitat Recovery Plan for the Alabama Beach Mouse (Peromyscus polionotus ammobates). US Fish and Wildlife Service, Atlanta, GA.
Webster, P. J. , G. J. Holland , J. A. Curry and H. R. Chang (2005). Changes in tropical cyclone number, duration, and intensity in a warming environment. Science 309(5742): 1844–1846.