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The effects of environment and niche on the distributions of dwarf chameleons, present and future

Includes bibliographical references.

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Main Author: Houniet, Darren
Other Authors: Underhill, Les
Format: Thesis
Language:English
Published: Department of Statistical Sciences 2014
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access_status_str Open Access
author Houniet, Darren
author2 Underhill, Les
author_browse Houniet, Darren
Underhill, Les
author_facet Underhill, Les
Houniet, Darren
author_sort Houniet, Darren
collection Thesis
description Includes bibliographical references.
format Thesis
id oai:open.uct.ac.za:11427/7472
institution University of Cape Town (South Africa)
language eng
last_indexed 2026-06-10T12:33:49.949Z
license_str Not specified — see source repository
provenance_str_mv Harvested via OAI-PMH from UCTD — University of Cape Town Open Access Repository
publishDate 2014
publishDateRange 2014
publishDateSort 2014
publisher Department of Statistical Sciences
publisherStr Department of Statistical Sciences
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source_str UCTD — University of Cape Town Open Access Repository
spelling oai:open.uct.ac.za:11427/7472 The effects of environment and niche on the distributions of dwarf chameleons, present and future Houniet, Darren Underhill, Les Thuiller, Wilfried Tolley, Krystal A Midgley, Guy Statistical Sciences Includes bibliographical references. The niche and niche breadth of Dwarf Chameleons, Bradypodion, was assessed in terms of broad scale climatic factors. A niche-based modelling method was then used to construct present and future habitat suitability maps for 2050 and 2080, for species in the genus. Additionally, the relationship between environment and morphology was analysed for a representative Bradypodion species, the Cape Dwarf Chameleon, B. pumilum. The niche and niche breadth of species and phylogenetic clades were analysed and described via an ordination technique, the outlying mean index (OMI) analysis. Maxent (v2.3), a presence only niche modelling method, proved very useful in the construction of present and future habitat suitability maps for species within the genus. For analysis of the correspondence between environment and morphology for B. pumilum, regression trees were employed. Rainfall seasonality and maximum annual temperatures were shown to strongly effect the current distributions of the genus Bradypodion at both the species and clade level. Additionally, as closely related species inhabited similar environmental niches, the genus was shown to display a degree of niche conservatism. All species and clades were shown to respond to climate change scenarios for 2050 and 2080, but responses were individualistic. However, most demonstrated range contractions under predicted climate scenarios. Additionally, a strong correlation (p < 0.05) was found between the morphology of B. pumilum and its environment. Environmental factors explained over 40% of the variation in snout-vent length and tail length, and over 20% of the variation in head width and head height, thus supporting the hypothesis of a correspondence between vegetation and morphology in Bradypodion. These results have provided an understanding of the relationship between Bradypodion and their environments that could provide valuable information regarding their ecology. Additionally, the habitat suitability maps for 2050 and 2080 could prove useful in the construction of any future conservation plans for these species. Furthermore, the results support the hypothesis of a correspondence between environmental factors and morphological traits within the genus Bradypodion. 2014-09-15T07:29:24Z 2014-09-15T07:29:24Z 2007 Master Thesis Masters MSc http://hdl.handle.net/11427/7472 eng application/pdf Department of Statistical Sciences Faculty of Science University of Cape Town
spellingShingle Statistical Sciences
Houniet, Darren
The effects of environment and niche on the distributions of dwarf chameleons, present and future
thesis_degree_str Master's
title The effects of environment and niche on the distributions of dwarf chameleons, present and future
title_full The effects of environment and niche on the distributions of dwarf chameleons, present and future
title_fullStr The effects of environment and niche on the distributions of dwarf chameleons, present and future
title_full_unstemmed The effects of environment and niche on the distributions of dwarf chameleons, present and future
title_short The effects of environment and niche on the distributions of dwarf chameleons, present and future
title_sort effects of environment and niche on the distributions of dwarf chameleons present and future
topic Statistical Sciences
url http://hdl.handle.net/11427/7472
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