| dc.description.abstract | Abstract
1. Global climate change will be one of the biggest threats to biodiversity over the course of this century. 21st century biodiversity conservation thus depends much on our ability help species adapt. A better understanding of the importance of fine-scale spatial variation in climatic influence on biodiversity response to climate change is needed to apply management effectively. Current methods utilising coarse-scale variation may not account for the climate a species experiences, leading to inaccurate predictions of species response to climate change.
2. To better understand the importance of climatic influence on biodiversity, this thesis looks at the fine-scale patterns and environmental influences of plant community change in response to climate change, and how these responses can be manipulated through in situ management. The first data chapter in this thesis looks at the long-term, fine-scale patterns of a plant community’s response to climate change, and the drivers of these. The next data chapter looks at the processes by which microclimate influences the distribution of plants at the fine-scale, focussing on plant species from a range of major biomes. This thesis finishes with a review of the published evidence for whether in situ management can be effective in offsetting the adverse impacts of climate change through microclimate manipulation.
3. Chapter 2 looks at long-term, fine-scale changes in plant community composition on the Lizard Peninsula, United Kingdom, since 1900. Using species’ indices for temperature, nitrogen and moisture, mean community index values were calculated for 1 km2 grid cells over three periods: 1900-1958, 1986-1999 and 2000-2013. The change of each mean index value between these periods for each grid cell was modelled against spatial variation in a number of environmental variables including distance from the coast, and proxies of water availability and near-ground temperature. The change maps suggest that the majority of cells saw significant increase in January and July temperatures and moisture availability, and significant declines in nitrogen availability. Recorded changes were influenced by distance to the coast, terrestrial warming, topographic wetness, elevation, dominant land cover, and spring solar index.
4. Chapter 3 looks at how habitat variation affected distribution of rare and threatened plant species. Random encounter surveys were carried out between May to September 2013, along public pathways on the Lizard peninsula. Slope, aspect, percentage bare ground cover, soil depth and vegetation height were then measured around individuals. These variables were compared between species with different preferences. This study finds that topography and sward height influence on microclimate affected species distribution. Species with the warmest and coolest temperature associations are both found in the warmest, driest microclimates. These microclimates are predominantly on south-facing, steep slopes with low sward cover.
5. Chapter 4 reviews the available literature to determine the suitability of in situ habitat management to manipulate microclimate to promote species persistence. Web of Science was used to search for key terms related to climate change and management, identifying 67 relevant papers for this review. Each management technique identified was then assessed for strength of evidence and risk of failure. This review finds that manipulation of habitat can be used to alter the microclimatic conditions organisms experience to mitigate the effects of climate
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change on species as regional climatic conditions became unsuitable. However, many manipulations are not ingrained in conservation practice, and may have negative impacts if applied without consideration.
6. Synthesis and applications. Overall, the findings outlined in this thesis suggest that fine-scale environmental variation influences species’ response to climate change. If there is a fine-scale influence on species distribution, using coarse-scale SDMs in heterogeneous environments may underestimate species persistence in their current range. Based on our review, in situ management is effective at manipulating local environments to offset the effects of climate change. By exploiting this knowledge, conservation managers could manipulate habitat to influence species response to climate change, and more effectively conserve biodiversity. | en_GB |
