Characterizing microclimates as potential thermal buffers for reptiles, birds, and mammals in an arid-zone environment
| dc.contributor.author | Warner, Grace M. | |
| dc.contributor.co-supervisor | Alexander, Graham J. | |
| dc.contributor.supervisor | Fuller, Andrea | |
| dc.date.accessioned | 2024-11-16T15:17:26Z | |
| dc.date.available | 2024-11-16T15:17:26Z | |
| dc.date.issued | 2023 | |
| dc.description | A dissertation submitted in fulfilment of the requirements for the degree Master of Science, to the Faculty of Science, School of Animal, Plant and Environmental Sciences, University of the Witwatersrand, Johannesburg, 2023. | |
| dc.description.abstract | Aridification, increases in air temperatures and frequency of extreme weather events, such as heat waves, are predicted to intensify under climate change, suggesting dire consequences for dryland animals. Microhabitats may buffer dryland animals against the changing climate, yet microclimatic data remains scarce from Africa and arid regions. The distribution, abundance, and thermal buffering capacity of five microhabitat types (burrows, nests, rock crevices, tree hollows and vegetation) were investigated across three habitat types (dunes, plains, and mountains) in the Kalahari. The distribution and abundance of microhabitats were assessed via strip transects, while thermal buffering capacity was evaluated by comparing miniature black globe temperatures from 70 representative sheltered microhabitats with 12 localised exposed-site microhabitats. The data generated have provided a baseline measure of the abundance and distribution of microhabitats in the Kalahari and have produced a year-long fine-resolution microclimatic thermal dataset. Microhabitat types and abundance were found to differ per habitat type and across topographic gradients. Abiotic drivers, such as soil type and fire frequency, along with drivers such as biotic community composition, were highlighted as potential causes of these microhabitat distribution patterns. Burrows were the best buffered microhabitat across all tested temporal and spatial gradients, providing an average maximum decrease of -29.5 ˚C during the day, and an average maximum increase of 20.1 ˚C during the night. Well-buffered microhabitats were rare within the field-site, whereas some of the poorest buffering microhabitats (Vegetation) were abundant and widespread. Thus, competition for well-buffered microhabitats may increase under climate change, whilst the risk of traversing large distances between microhabitats may become too great for smaller animals as exposure risk to extreme temperatures increases. Furthermore, birds and large mammals may likely be at a high risk of extreme temperature exposure, as their size and structural adaptations may restrict them from access to well-buffered microhabitats. Therefore, the need for the concurrent assessments of microhabitat distribution, abundance and buffering capacity in future species vulnerability assessments is highlighted, as it is the combination of these factors that are likely to impact population viability under climate change. | |
| dc.description.sponsorship | Oppenheimer Generations Research and Conservation Fund. | |
| dc.description.sponsorship | National Research Foundation (NRF). | |
| dc.description.sponsorship | The Rufford Foundation. | |
| dc.description.sponsorship | The Tswalu Foundation. | |
| dc.description.sponsorship | University of the Witwatersrand, Johannesburg - Faculty of Health Sciences. | |
| dc.description.sponsorship | Suzuki South Africa. | |
| dc.description.submitter | MMM2024 | |
| dc.faculty | Faculty of Science | |
| dc.identifier | 0000-0003-0840-0319 | |
| dc.identifier.citation | Warner, Grace M. (2023). Characterizing microclimates as potential thermal buffers for reptiles, birds, and mammals in an arid-zone environment. [Master's dissertation, University of the Witwatersrand, Johannesburg]. https://hdl.handle.net/10539/42619 | |
| dc.identifier.uri | https://hdl.handle.net/10539/42619 | |
| dc.language.iso | en | |
| dc.publisher | University of the Witwatersrand, Johannesburg | |
| dc.rights | ©2023 University of the Witwatersrand, Johannesburg. All rights reserved. The copyright in this work vests in the University of the Witwatersrand, Johannesburg. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of University of the Witwatersrand, Johannesburg. | |
| dc.rights.holder | University of the Witwatersrand, Johannesburg | |
| dc.school | School of Animal, Plant and Environmental Sciences | |
| dc.subject | Climate change | |
| dc.subject | Drylands | |
| dc.subject | Thermal biology | |
| dc.subject | Microhabitat | |
| dc.subject | Buffering capacity | |
| dc.subject | UCTD | |
| dc.subject.other | SDG-13: Climate action | |
| dc.title | Characterizing microclimates as potential thermal buffers for reptiles, birds, and mammals in an arid-zone environment | |
| dc.type | Dissertation |