Colonisation credit in recent wet heathland butterfly communities

Authors


Sara Cristofoli, University of Liege, Gembloux Agro-Bio Tech, Laboratory of Ecology Passage des déportés 2, 5030 Gembloux, Belgium. E-mail: cristofoli.s@fsagx.ac.be

Abstract

Abstract.  1. Wet heathlands and closely associated habitats (e.g. bogs and poor fens) have been highly fragmented over the last two centuries. These habitats nowadays benefit from large-scale restoration projects, for which the success should be evaluated.

2. Recently, the concept of colonisation credit (the number of species yet to colonise a patch) was proposed as a spatially explicit framework to assess recovery in species richness following restoration. In this study, we estimated the colonisation credit of wet heathland butterfly communities in Southern Belgium. The method was applied separately to generalist and specialist species for two reference dates (new patches <25 years old and new patches 25–55 years old).

3. Only a marginally significant colonisation credit was detected for generalist species. In contrast, we found a significant colonisation credit for specialists, although this was due to a very limited number of strict specialist species. Butterfly community composition differed only marginally between patch age classes.

4. As a general trend, butterfly communities exhibit a rapid response (<25 years) to landscape structure modification. However, conservation and restoration actions should urgently target strict specialists, exhibiting colonisation limitation in new habitat patches. A lack of colonisation credit for plant communities in the same landscape suggests that restoration of wet heathlands may be successful in the short term for various taxonomic groups.

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