Climatic Correlates of Plant Species Distributions in Alpine New Zealand
|dc.contributor.author||Clarke, Amy Georgina|
|dc.identifier.citation||Clarke, A. G. (2016). Climatic Correlates of Plant Species Distributions in Alpine New Zealand (Thesis, Master of Science). University of Otago. Retrieved from http://hdl.handle.net/10523/6851||en|
|dc.description.abstract||New Zealand’s alpine environment is characterised by high levels of endemism with more than 90% of plant species found in the alpine zone being endemic to New Zealand. The South Island shows clear disjunct distribution patterns in several alpine plant species, and two species-rich endemism centres located at either end of the Island. Quantifying the relationship between climatic conditions and floristic composition of New Zealand’s alpine flora underlying these patterns is crucial for understanding the role of climate in determining species distribution patterns. The aim of this study is to assess patterns in climate conditions and species composition in New Zealand, and to characterize and analyse the climatic niche conditions of disjunct vascular species. This study also identifies whether the central South Island is acting as a climatic barrier between the northern and southern disjunct populations, preventing them from colonising the central region. To determine such relationships, New Zealand was divided into five regions and the South Island into six subregions. Land area was categorised as above or below treeline, allowing comparisons to be made along a latitudinal and altitudinal axis. Published climate and species distribution data were used to determine climatic conditions and species composition patterns. Occurrence records for ten endemic species from five genera, five disjunct and five continuous species, were used to investigate the relationship between climate and disjunctions in the South Island. Throughout New Zealand and the South Island, climate conditions were more similar between nearby regions than between distant regions. Across New Zealand and below the treeline in the South Island, nearby regions contained a more similar set of species than distant regions. Above the treeline in the South Island, the endemism centres had a similar set of species while the composition of species in the central region was distinctly different to that of the endemism centres. This study found evidence of a niche shift wherein the disjunct populations now occupy distinctly different niche conditions in the endemism centres. The central South Island was too climatically similar to the climate of the endemism centres to conclude that it might act as a distinct climatic barrier between the disjunct populations. This study demonstrated that there are large-scale climatic correlates with species distributions in New Zealand. Quantifying the relationship between these climate-vegetation relationships and the spatial patterns they drive can improve our understanding of New Zealand vegetation in light of past and future climate change.|
|dc.publisher||University of Otago|
|dc.rights||All items in OUR Archive are provided for private study and research purposes and are protected by copyright with all rights reserved unless otherwise indicated.|
|dc.title||Climatic Correlates of Plant Species Distributions in Alpine New Zealand|
|thesis.degree.name||Master of Science|
|thesis.degree.grantor||University of Otago|
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