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Spatial dynamics of the knob-tailed gecko Nephrurus stellatus in a fragmented agricultural landscape
journal contribution
posted on 2012-07-01, 00:00 authored by Don DriscollDon Driscoll, C A Whitehead, J LazzariIn fragmented landscapes, a species' dispersal ability and response to habitat condition are key determinants of persistence. To understand the relative importance of dispersal and condition for survival of Nephrurus stellatus (Gekkonidae) in southern Australia, we surveyed 92 woodland remnants three times. This gecko favours early post-fire succession conditions so may be at risk of extinction in the long-unburnt agricultural landscape. Using N-mixture models, we compared the influence of four measures of isolation, patch area and two habitat variables on the abundance and occurrence of N. stellatus, while taking into account detection probability. Patch occupancy was high, despite the long-term absence of fire from most remnants. Distance to the nearest occupied site was the most informative measure of patch isolation, exhibiting a negative relationship with occupancy. Distance to a nearby conservation park had little influence, suggesting that mainland-island metapopulation dynamics are not important. Abundance and occurrence were positively related to %-cover of spinifex (Triodia), indicating that niche-related factors may also contribute to spatial dynamics. Patterns of patch occupancy imply that N. stellatus has a sequence of spatial dynamics across an isolation gradient, with patchy populations and source-sink dynamics when patches are within 300 m, metapopulations at intermediate isolation, and declining populations when patches are separated by >1-2 km. Considering the conservation needs of the community, habitat condition and connectivity may need to be improved before fire can be reintroduced to the landscape. We speculate that fire may interact with habitat degradation and isolation, increasing the risk of local extinctions.
History
Journal
Landscape ecologyVolume
27Issue
6Pagination
829 - 841Publisher
SpringerLocation
Amsterdam, The NetherlandsPublisher DOI
ISSN
0921-2973eISSN
1572-9761Language
engPublication classification
C1.1 Refereed article in a scholarly journal; C Journal articleCopyright notice
2012, Springer Science+Business Media B.V.Usage metrics
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Categories
Keywords
MetacommunityReptilePatch-matrix modelInvasive weedsLand clearingScience & TechnologyLife Sciences & BiomedicinePhysical SciencesEcologyGeography, PhysicalGeosciences, MultidisciplinaryEnvironmental Sciences & EcologyPhysical GeographyGeologyINCIDENCE FUNCTION MODELHABITAT FRAGMENTATIONMETAPOPULATION DYNAMICSRESTORATION ECOLOGYPATCHY POPULATIONSMALL MAMMALSFIREEXTINCTIONCONNECTIVITYRESPONSES