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Northern Territory University (1999)

The effect of a temporally variable environment and grazing on lizards in mulga (Acacia aneura) shrublands of central Australia

Schlesinger, Christine A.

Titre : The effect of a temporally variable environment and grazing on lizards in mulga (Acacia aneura) shrublands of central Australia

Auteur : Schlesinger, Christine A.

Université de soutenance : Northern Territory University

Grade : Doctor of Philosophy (PhD) 1999

Résumé
The provision of artificial sources of water for domestic stock in arid Australia has resulted in high levels of grazing over extensive areas, and the impact on native fauna is likely to be widespread. However, there is little direct evidence of the effect of grazing on lizards, and particularly on the relationship between climate variability and grazing in detennining the distribution and abundance of lizard assemblages. This study investigates the effect of grazing on ground-active lizards in a highly variable climate. Populations of ground-dwelling lizards were monitored at eight sites between September 1993 and December 1995. The study sites were in mulga (Acacia aneura) tall shrubland on a pastoral property in central Australia, where sites were categorised as having high and low levels of grazing based on their distance from artificial water points for cattle. Because lizards were sampled solely by means of pitfall traps, I conducted an experiment to test the hypothesis that ground cover affects the efficiency of pitfall traps in capturing lizards. Reducing ground cover had no effect on the subsequent rates at which lizards were captured, compared with control sites, or rates of capture before grass was cut. I conclude that pitfall-trapping is a valid technique for comparing lizard populations in mulga shrublands which are subject to different levels of grazing within the range of vegetation covers used in this study.

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