Dispersal, distribution, patch network and metapopulation dynamics of the dingy skipper butterfly (Erynnis tages) |
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Authors: | D Gutiérrez Chris D Thomas Jorge L León-Cortés |
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Institution: | (1) Centre for Biodiversity and Conservation, School of Biology, University of Leeds, Leeds LS2 9JT, UK, GB |
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Abstract: | Two general approaches have usually been taken towards understanding the distributions and dynamics of localised species in
heterogeneous landscapes, namely habitat characterisation and metapopulation dynamics. We show how habitat and metapopulation
dynamics interact to generate a highly localised distribution of a butterfly, despite the extremely widespread nature of the
butterfly’s host plant. Egg placement, macro-habitat requirements and dispersal were studied for the butterfly Erynnis tages, in North Wales, where it shows a restricted distribution relative to that of its host plant, Lotus corniculatus. Females laid eggs disproportionately on large plants growing in hollows, with intermediate cover of bare ground and high
cover of L. corniculatus. Ideal macro-habitat, studied at 100-m grid resolution, consisted of areas with high host plant densities, sheltered from
wind, with light or no grazing or cutting. These specialised conditions are represented as localised patches in the landscape,
and define the potential habitat network, within which metapopulation dynamics take place. Although there was a moderate (22%)
level of exchange of individual E. tages among local populations, the total number of potential colonists in the whole system was low because source population sizes
were small (≤200 individuals at peak in any site in 1997 and 1998). Four unoccupied but apparently suitable 500-m grid squares
were colonised between 1997 and 1998, and isolated habitat was less likely to be occupied. Overall, our study suggests that
long-term regional persistence of E. tages is very likely to depend on metapopulation processes within the restricted patch network, rather than on the long-term survival
of local populations.
Received: 25 May 1999 / Accepted: 9 August 1999 |
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Keywords: | Conservation Erynnis tages Habitat fragmentation Habitat requirements Metapopulation |
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