AbstractDespite over 40 years of research investigating nature reserve design, many aspects of it remain a topic of debate. The optimal solution depends on numerous factors including the size and number of habitat patches, between-patch connectivity, and hostility of the non- habitat matrix. However, there is limited knowledge about how the optimal strategy can depend on the desired conservation outcome – to reduce extinction rates, increase species diversity, or conserve a target species whose trophic level, specialism, or mobility may affect its response. In addition, there is a poor understanding of the relative importance of each reserve design feature and therefore where best to invest conservation funds.
In this thesis I describe an experiment designed to investigate the effects of the number of habitat patches, patch-size variance, corridor-dispersal frequency, and matrix- dispersal mortality risk on protist metacommunities. Measuring alpha, beta, and gamma diversity, number of extinctions, and specialist and generalist predator survival probability reveals how the desired conservation outcome can affect the apparent optimal reserve configuration. I find that increasing the number of patches and patch-size variance has consistent positive effects, reducing extinctions, increasing specialist predator survival probability, and increasing each of the three diversity metrics considered. Interestingly this pattern is reversed for the generalist predator, whose survival probability declines as the number of patches increases. Furthermore, the effects of dispersal can be counter-intuitive, with corridor dispersal having no significant effects whilst dispersal across the matrix increases specialist predator survival probability but has no effect on generalist predator survival probability. The implications of this research are that (a) heterogeneity of patch size is a key driver of diversity, (b) future research should move beyond species richness towards a more holistic approach which considers multiple conservation goals simultaneously, and (c) species interactions play an important role in structuring responses to reserve configuration.
|Date of Award||23 Mar 2021|
|Supervisor||Chris F Clements (Supervisor) & Jane Memmott (Supervisor)|