Population demography of an endangered lizard, the Blue Mountains Water Skink
- Sylvain DubeyAffiliated withDepartment of Ecology and Evolution, University of Lausanne Email author
- , Ulrich SinschAffiliated withDepartment of Biology, Universität Koblenz-Landau, IfIN
- , Maximilian J DehlingAffiliated withDepartment of Biology, Universität Koblenz-Landau, IfIN
- , Maya ChevalleyAffiliated withDepartment of Ecology and Evolution, University of Lausanne
- , Richard ShineAffiliated withSchool of Biological Sciences A08, University of Sydney
Information on the age structure within populations of an endangered species can facilitate effective management. The Blue Mountains Water Skink (Eulamprus leuraensis) is a viviparous scincid lizard that is restricted to < 40 isolated montane swamps in south-eastern Australia. We used skeletochronology of phalanges (corroborated by mark-recapture data) to estimate ages of 222 individuals from 13 populations.
These lizards grow rapidly, from neonatal size (30 mm snout-vent length) to adult size (about 70 mm SVL) within two to three years. Fecundity is low (mean 2.9 offspring per litter) and is affected by maternal body length and age. Offspring quality may decline with maternal age, based upon captive-born neonates (older females gave birth to slower offspring). In contrast to its broadly sympatric (and abundant) congener E. tympanum, E. leuraensis is short-lived (maximum 6 years, vs 15 years for E. tympanum). Litter size and offspring size are similar in the two species, but female E. leuraensis reproduce annually whereas many E. tympanum produce litters biennially. Thus, a low survival rate (rather than delayed maturation or low annual fecundity) is the key reason why E. leuraensis is endangered. Our 13 populations exhibited similar growth rates and population age structures despite substantial variation in elevation, geographic location and swamp size. However, larger populations (based on a genetic estimate of effective population size) contained older lizards, and thus a wider variance in ages.
Our study suggests that low adult survival rates, as well as specialisation on a rare and fragmented habitat type (montane swamps) contribute to the endangered status of the Blue Mountains Water Skink.
KeywordsAustralia Montane species Reptile Skeletochronology
- Population demography of an endangered lizard, the Blue Mountains Water Skink
- Open Access
- Available under Open Access This content is freely available online to anyone, anywhere at any time.
- Online Date
- February 2013
- Online ISSN
- BioMed Central
- Additional Links
- Author Affiliations
- 1. Department of Ecology and Evolution, University of Lausanne, Biophore Bld, Lausanne, 1015, Switzerland
- 2. Department of Biology, Universität Koblenz-Landau, IfIN, Universitätsstr. 1, Koblenz, D-56075, Germany
- 3. School of Biological Sciences A08, University of Sydney, Sydney, NSW, 2006, Australia