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Ecology and health of the Asian water monitor lizard (Varanus salvator) In the fragmented landscape of the Kinabatangan floodplain, Sabah, Malaysia

Guerrero Sanchez, Sergio 2019. Ecology and health of the Asian water monitor lizard (Varanus salvator) In the fragmented landscape of the Kinabatangan floodplain, Sabah, Malaysia. PhD Thesis, Cardiff University.
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The Asian water monitor lizard (Varanus salvator) is well adapted to anthropogenic landscapes. Its abundance makes the species a good candidate to assess ecosystem health and the influence of human-modified habitats over adjacent forests. In order to understand how habitat fragmentation in the Kinabatangan Floodplain influences the dynamics of monitor lizard populations, 402 lizards were trapped, measured and sampled to obtain information regarding population size. From these, 14 individuals were tagged with Geographic Position System devices to estimate home range and habitat utilization. Additionally, a set of bio-markers were analysed from blood and a parasitological assessment was conducted. Results showed that a larger number of lizards inhabit forested areas (!̅ = 1,492 ind.) than oil palm plantations (!̅ = 280 ind.), while home ranges (Minimum Convex Polygon; MCP) were smaller in plantations (!̅MCP = 1.54 km2) than in forested areas (!̅MCP = 3.920 km2). In both habitats, water bodies and dense riparian understory were a more suitable habitat for monitor lizards. High levels of bio-markers such as low-density cholesterol, albumin and uric acid, as well as higher abundance of generalist parasites were associated with a rodentdominated diet in plantations. Amblyomma helvolum was the only ixodid tick detected in the lizard population, with a higher abundance in plantations than in forested areas. Tick abundance was associated with body size, abundance, and the presence of grasslands and riparian understory. This study covers the most extensive ecological analysis of the Asian water monitor lizard to date and generated information that can be used to monitor habitat quality. Lastly, the data presented here support the idea that the Asian water monitor lizard population in the Kinabatangan Floodplain is stable and widely distributed across the landscape, with its diet indicating differences in availability through the landscape, and reflecting the condition of such a fragmented ecosystem.

Item Type: Thesis (PhD)
Date Type: Completion
Status: Unpublished
Schools: Biosciences
Subjects: Q Science > QL Zoology
Date of First Compliant Deposit: 18 October 2019
Last Modified: 20 Oct 2021 01:27

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