High dispersal in a frog species suggests that it is vulnerable to habitat fragmentation
Abstract
Global losses of amphibian populations are a major conservation concern and have generated substantial debate over their causes. Habitat fragmentation is considered one important cause of amphibian decline. However, if fragmentation is to be invoked as a mechanism of amphibian decline, it must first be established that dispersal is prevalent among contiguous amphibian populations using formal movement estimators. In contrast, if dispersal is naturally low in amphibians, fragmentation can be disregarded as a cause of amphibian declines and conservation efforts can be focused elsewhere. We examined dispersal rates in Columbia spotted frogs (Rana luteiventris) using capture–recapture analysis of over 10 000 frogs in combination with genetic analysis of microsatellite loci in replicate basins. We found that frogs had exceptionally high juvenile dispersal rates (up to 62% annually) over long distances (>5 km), large elevation gains (>750 m), and steep inclines (36° incline over 2 km) that were corroborated by genetic data showing high gene flow. These findings show that dispersal is an important life-history feature of some amphibians and suggest that habitat fragmentation is a serious threat to amphibian persistence.
Footnotes
References
-
Alford R.A& Richards S.J . 1999 Global amphibian declines: a problem in applied ecology. Annu. Rev. Ecol. Syst 30, 133–165.DOI:10.1146/annurev.ecolsys.30.1.133. Crossref, Google Scholar -
Blaustein A.R, Wake D.B& Sousa W.P . 1994 Amphibian declines: judging stability, persistence, and susceptibility of populations to local and global extinctions. Conserv. Biol 8, 60–71.DOI:10.1046/j.1523-1739.1994.08010060.x. Crossref, ISI, Google Scholar -
Brown J.H& Kodric-Brown A . 1977 Turnover rates in insular biogeography: effect of immigration on extinction. Ecology 58, 445–449. Crossref, ISI, Google Scholar -
Cooch, E. G. & White, G. C. 2001 Using program Mark: a gentle introduction. [online] http://www.phidot.org/software/mark/docs/book/ Cornell University & Colorado State University Cooperative Wildlife Units. Google Scholar
-
Donnelly M.A, Guyer C, Juterbock J.E& Alford R.A . 2001 Techniques for marking amphibians., Heyer W.R, Donnelly M.A, McDiarmid R.W, Hayek L.-A.C& Foster M.S In Measuring and monitoring biological diversity. Standard methods for amphibians Washington, DC:Smithsonian Institution Press 277–284. Google Scholar -
Funk, W. C., Blouin, M. S., Corn, P. S., Maxell, B. A., Pilliod, D. S., Amish, S. & Allendorf, F. W. Submitted Population structure of Columbia spotted frogs (Rana luteiventris) is strongly affected by the landscape. Mol. Ecol. Google Scholar
-
Goudet J . 1995 Fstat version 1.2: a computer program to calculate F-statistics. J. Hered 86, 485–486. Crossref, ISI, Google Scholar -
Hitchings S.P& Beebee T.J.C . 1997 Genetic substructuring as a result of barriers to gene flow in urban Rana temporaria (common frog) populations: implications for biodiversity conservation. Heredity 79, 117–127. Crossref, PubMed, ISI, Google Scholar -
Johnston B& Frid L . 2002 Clearcut logging restricts the movements of terrestrial Pacific giant salamanders (Dicamptodon tenebrosus Good). Can. J. Zool 80, 2170–2177. Crossref, ISI, Google Scholar -
Lebreton J.-D, Burnham K.P, Clobert J& Anderson D.R . 1992 Modeling survival and testing biological hypotheses using marked animals: a unified approach with case studies. Ecol. Monogr 62, 67–118. Crossref, ISI, Google Scholar -
Lowe W.H . 2003 Linking dispersal to local population dynamics: a case study using a headwater salamander system. Ecology 84, 2145–2154. Crossref, ISI, Google Scholar -
Marsh D.M& Trenham P.C . 2001 Metapopulation dynamics and amphibian conservation. Conserv. Biol 15, 40–49.DOI:10.1046/j.1523-1739.2001.00129.x. Crossref, ISI, Google Scholar -
Nichols J.D& Kendall W.L . 1995 The use of multi-state capture–recapture models to address questions in evolutionary ecology. J. Appl. Stat 22, 835–846.DOI:10.1080/02664769524658. Crossref, ISI, Google Scholar -
Parris K.M& McCarthy M.A . 2001 Identifying effects of toe-clipping on anuran return rates: the importance of statistical power. Amphib. Reptil 22, 275–289. Crossref, ISI, Google Scholar -
Seaber P.R, Kapinos F.P& Knapp G.L . 1984 Hydrologic unit maps.In Water-supply paper no. 2294 US Geological Survey:Denver, CO. Google Scholar -
Sjögren P . 1991 Extinction and isolation gradients in metapopulations: the case of the pool frog (Rana lessonae). Biol. J. Linn. Soc 42, 135–147. Crossref, ISI, Google Scholar -
Slatkin M . 1995 A measure of population subdivision based on microsatellite allele frequencies. Genetics 139, 457–462. Crossref, PubMed, ISI, Google Scholar -
Tallmon D.A, Luikart G& Waples R.S . 2004 The alluring simplicity and complex reality of genetic rescue. Trends Ecol. Evol 19, 489–496.DOI:10.1016/j.tree.2004.07.003. Crossref, PubMed, ISI, Google Scholar -
Trenham P.C, Koenig W.D& Shaffer H.B . 2001 Spatially autocorrelated demography and interpond dispersal in the salamander Ambystoma californiense. Ecology 82, 3519–3530. Crossref, ISI, Google Scholar -
Waichman A.V . 1992 An alphanumeric code for toe clipping amphibians and reptiles. Herpetol. Rev 23, 19–21. Google Scholar -
White G.C& Burnham K.P . 1999 Program Mark: survival estimation from populations of marked animals. Bird Study Suppl 46, 120–139. Crossref, ISI, Google Scholar -
Wright S . 1969 Evolution and the genetics of populations.In The theory of gene frequencies vol. 2 Chicago:University of Chicago Press. Google Scholar