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Type: Theses
Title: Quantifying responses of ecological communities to bioclimatic gradients
Author: Caddy-Retalic, Stefan
Issue Date: 2017
School/Discipline: School of Biological Sciences
Abstract: The biotic change along environmental gradients has been the subject of study for well over a century, forming one of the first tools to understand how environment shapes the species and ecosystems that occur. However, gradient studies have historically relied on limited observations on a single transect, limiting their inductive power. Here, I investigate how this limitation can be addressed. I present case studies to illustrate how next-generation transect studies can integrate observations from a wider range of observations of phenotypes, species and communities; together with observations from multiple taxa and gradients. Leaf carbon isotope data from bioclimatic gradients in China, South Australia and Western Australia are integrated to demonstrate a variety of species- and community-level responses to water availability, providing evidence against the previously asserted claim of a simple and universal response. Vegetation data from the same gradient is surveyed with two separate survey methodologies are co-analysed to demonstrate climate is the primary regional determinant of vegetation structure and composition in South Australia, while topographic and edaphic variables are important at a local scale. I find no evidence of ecological disjunctions that may indicate a threshold of vegetation change associated with climate shifts. Comparison of plant and ant species turnover on a spatial gradient suggested that ant communities are ca. 7.5 times more sensitive than plant assemblages to spatial change, providing evidence that future climate change may force community reorganisation and a decoupling of these two taxa, potentially disrupting important interactions and ecosystem function. Well-designed transect studies have the potential to help resolve long-standing questions around the modes of species adaptation to change, as well as improving our understanding of how climate change will shape ecosystems in to the future
Advisor: Lowe, Andrew
McInerney, Francesca
Dissertation Note: Thesis (Ph.D.) (Research by Publication) -- University of Adelaide, School of Biological Sciences, 2018
Keywords: Research by publication
carbon isotopes
community congruence
climate change
Provenance: This electronic version is made publicly available by the University of Adelaide in accordance with its open access policy for student theses. Copyright in this thesis remains with the author. This thesis may incorporate third party material which has been used by the author pursuant to Fair Dealing exceptions. If you are the owner of any included third party copyright material you wish to be removed from this electronic version, please complete the take down form located at:
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