Altitudinal variation in the communities of small mammals in the central Himalaya of Nepal

Poulton, Simon Maurice Charles (2019) Altitudinal variation in the communities of small mammals in the central Himalaya of Nepal. Doctoral thesis, University of East Anglia.

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Altitudinal variation in small mammal communities has been studied in many parts of the world, such as the Rocky Mountains in USA, the Andes of South America and a number of gradients in Tanzania, China, Malaysia and the Philippines. However, no specific elevational studies have been carried out in the Himalaya of Nepal – the region with the largest altitudinal gradients in the world. This six year study sets out to redress this shortfall, and its geographical and temporal scope make it the largest ecological small mammal survey ever undertaken in the Nepali Himalaya. Fieldwork was undertaken over three years in four regions on 147 live-trapping grids at altitudes between 1300m and 4400m, comprising 8046 trap events. 792 animals were caught belonging to 18 putative taxa, with a dominance of shrews not recorded in previous studies. Habitat data was used to characterise the grids, with a combination of cluster analysis and a novel genetic algorithm. The abundance of various small mammal species showed strong associations with different grid characteristics.

To aid species identification, two additional data sources were explored. Firstly, over 8000 historical records of small mammals were compiled from museum records and used to generate predictive models of distributions in Nepal. Secondly, 720 tissue samples were collected in the field, from which a sub-sample yielded 94 successful sequences of the cytochrome-b gene. Detailed phylogenetic analyses of 200 sequences from GenBank combined with the field-derived sequences, consolidated their identifications into 17 taxa and suggested previously unrecorded cryptic species of voles and shrews.

The main ecological findings of this study were that a) overall species abundance showed a significant decline with altitude and a significant variation between regions, b) there was compelling evidence for competitive exclusion between two species of mouse, c) there was strong evidence of altitudinal zonation for many species, and d) both α and β-diversity showed strong elevational and regional variation.

Item Type: Thesis (Doctoral)
Faculty \ School: Faculty of Science > School of Biological Sciences
Depositing User: Jennifer Whitaker
Date Deposited: 18 Oct 2019 11:02
Last Modified: 10 Jan 2021 01:38

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