Habitat fragmentation may not matter to species diversity
Abstract
Conservation biologists worry that fragmenting a bloc of natural habitat might reduce its species diversity. However, they also recognize the difficulty and importance of isolating the effect of fragmentation from that of simple loss of area. Using two different methods (species–area curve and Fisher's α index of diversity) to analyse the species diversities of plants, tenebrionid beetles and carabid beetles in a highly fragmented Mediterranean scrub landscape, we decoupled the effect of degree of fragmentation from that of area loss. In this system, fragmentation by itself seems not to have influenced the number of species. Our results, obtained at the scale of hectares, agree with similar results at island and continent scales.
References
-
Fahrig L . 2003 Effects of habitat fragmentation on biodiversity. Annu. Rev. Ecol. Evol. Syst. 34, 487–515.doi:10.1146/annurev.ecolsys.34.011802.132419. . Crossref, ISI, Google Scholar -
Fisher R.A, Corbet A.S& Williams C.B . 1943 The relation between the number of species and the number of individuals in a random sample from an animal population. J. Anim. Ecol. 12, 42–58.doi:10.2307/1411. . Crossref, Google Scholar -
Haila Y . 2002 A conceptual genealogy of fragmentation research: from island biogeography to landscape ecology. Ecol. Appl. 12, 321–334. ISI, Google Scholar -
Harrison S& Bruna E . 1999 Habitat fragmentation and large-scale conservation: what do we know for sure?. Ecography. 22, 225–232.doi:10.1111/j.1600-0587.1999.tb00496.x. . Crossref, ISI, Google Scholar -
Lomolino M.V . 1994 An evaluation of alternative strategies for building networks of nature-reserves. Biol. Conserv. 69, 243–249.doi:10.1016/0006-3207(94)90423-5. . Crossref, ISI, Google Scholar -
Lubchenco J, 1991 The sustainable biosphere initiative: an ecological research agenda. Ecology. 72, 371–412.doi:10.2307/2937183. . Crossref, ISI, Google Scholar -
Rosenzweig M.L Species diversity in space and time. 1995 Cambridge, UK:Cambridge University Press. Google Scholar -
Rosenzweig M.L . 2001 The four questions: what does the introduction of exotic species do to diversity?. Evol. Ecol. Res. 3, 361–367. ISI, Google Scholar -
Rosenzweig M.L Applying species–area relationships to the conservation of species diversity. Frontiers of biogeography: new directions in the geography of nature, Lomolino M.V& Lawrence R.H . 2004pp. 325–344. Eds. Sunderland, MA:Sinauer Associates. Google Scholar -
Slobodkin L.B . 2001 The good, the bad and the reified. Evol. Ecol. Res. 3, 1–13. ISI, Google Scholar -
Tscharntke T, Steffan-Dewenter I, Kruess A& Theis C . 2002 Contribution of small habitat fragments to conservation of insect communities of grassland–cropland landscapes. Ecol. Appl. 12, 354–363. ISI, Google Scholar -
Wilson E.O& Willis E.O Applied biogeography. Ecology and evolution of communities, Cody M.L& Diamond J.M . 1975pp. 522–534. Eds. Cambridge, UK:Harvard University Press. Google Scholar -
Yaacobi G, Ziv Y& Rosenzweig M.L . 2007 Effects of interactive scale-dependent variables on beetle diversity patterns in a semiarid ecosystem. Landscape Ecol. 22, 687–703.doi:10.1007/s10980-006-9061-7. . Crossref, ISI, Google Scholar