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Distributional patterning of terrestrial herpetofauna on the Wessel and English Company Island groups, northeastern Arnhem Land, Northern Territory, Australia

Woinarski, John C. Z., Horner, P., Fisher, Alaric, Brennan, K., Lindner, D., Gambold, Nic, Chatto, R. and Morris, Ian (1999). Distributional patterning of terrestrial herpetofauna on the Wessel and English Company Island groups, northeastern Arnhem Land, Northern Territory, Australia. Austral Ecology,24(1):60-79.

Document type: Journal Article
Citation counts: Scopus Citation Count Cited 9 times in Scopus Article | Citations

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Title Distributional patterning of terrestrial herpetofauna on the Wessel and English Company Island groups, northeastern Arnhem Land, Northern Territory, Australia
Author Woinarski, John C. Z.
Horner, P.
Fisher, Alaric
Brennan, K.
Lindner, D.
Gambold, Nic
Chatto, R.
Morris, Ian
Journal Name Austral Ecology
Publication Date 1999
Volume Number 24
Issue Number 1
ISSN 1442-9985   (check CDU catalogue open catalogue search in new window)
Scopus ID 2-s2.0-17944371878
Start Page 60
End Page 79
Total Pages 20
Place of Publication Australia
Publisher Wiley-Blackwell Publishing Asia
Field of Research ENVIRONMENTAL SCIENCES
Abstract Forty-four species of terrestrial reptiles and eight species of frogs were recorded from 60 continental islands of the Wessel and English Company groups off northeastern Arnhem Land, Northern Territory. Two gecko species, Oedura rhombifer and Heteronotia binoei, were present on the most islands (34 and 31, respectively), and occurred on islands < 5 ha. In contrast, agamids, pygopodids and varanids were absent from islands < 18 ha, and snakes and frogs were not reported from islands < 240 ha. Island size explained 82% of the variation in species richness for terrestrial reptiles, and 84% of that for lizards. The relationship was less good for (i) groups with generally uncommon species (notably snakes), for which sampling effort explained more variation, and (ii) groups with species which had relatively specific habitat requirements (notably frogs), for which island size and isolation factors were not especially relevant. For most taxonomic groups considered, isolation factors added little to the relationship between species richness and island size. Across all reptiles, larger species were found on fewer islands, and had larger island size thresholds. This relationship broke down with analysis restricted to the single most species-rich family, Scincidae. Only 6 of the 20 most frequently recorded species showed significant variation in abundance among 8 vegetation types sampled by 226 quadrats across 40 islands. The number of species (alpha-diversity) and total abundance of herpetofauna within quadrats was generally unrelated to island size; however, (with analysis restricted to islands on which they occurred) six individual species were significantly more abundant on smaller islands than on larger islands, with no species showing the opposite pattern. The islands’ herpetofauna is largely a relatively depauperate subset of that of the far more complex sandstone massif and escarpment of western Arnhem Land, especially missing species associated with rugged sandstone gorges, riparian areas, open forests, swamps and clay soils. Patterns in species richness and composition are explained by greater range of environments on larger islands allowing better retention of species since isolation and/or richer tallies at the time of isolation. The evidence suggests that there has been relatively little colonization, although at least two gecko species and one varanid may have moved reasonably frequently.
Keywords Biogeography
Frogs
Islands
Reptiles
DOI http://dx.doi.org/10.1046/j.1442-9993.1999.00947.x   (check subscription with CDU E-Gateway service for CDU Staff and Students  check subscription with CDU E-Gateway in new window)
 
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