Tropical species are facing multiple environmental pressures, whereby agricultural expansion is causing rainforest loss and climate warming is resulting in range shifts to higher elevations. In Southeast Asia, biodiversity is severely threatened by oil palm expansion and much of the remaining lowland rainforest persists within isolated fragments and protected areas (PAs). I assessed the permeability of oil palm plantations to forest dependent species by examining boundary crossing abilities of fruit-feeding butterflies. I showed that crossing was dominated by species that could potentially breed within oil palm plantations, suggesting that plantations may act as dispersal barriers to forest species. Using the PA network on Borneo as a model system, I examined the spatial distribution of climate within PAs in future, and examined the connectedness of PAs along elevation gradients. For the majority (~60-90%) of PAs, which were predominantly situated at low elevation, analogous climates in future will only be available at higher elevation, requiring species to move in order to track cooler climates. However, over half (~60-82%) of these PAs were too isolated for species with poor dispersal abilities to reach cooler, higher elevation PAs. Finally, I used a novel modelling approach based on electrical circuit theory to identify important areas of rainforest connecting PAs along elevation gradients, and showed considerable spatial overlap in expansion routes under contrasting projections of warming. Protected area extent on Borneo will need to increase by approximately one fifth (~17%) to conserve all important rainforest connections between PAs. I conclude that rainforest species may be particularly vulnerable to the impacts of continued agricultural expansion and climate change, as they may be unable to move across fragmented landscapes due to lack of connecting rainforest habitat. Management to improve linkage of PAs and ensure protection of important dispersal routes along elevation gradients should be a conservation priority.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:722817 |
| Date | January 2016 |
| Creators | Scriven, Sarah Anne-Leigh |
| Contributors | Hill, Jane K. |
| Publisher | University of York |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://etheses.whiterose.ac.uk/17757/ |
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