ASSESSING BIODIVERSITY CHANGE ON ISLANDS THROUGH TIME: A MULTISCALE APPROACH

Islands have long fascinated ecologists given their high diversity (>20% of global species in ~5% of the land), which includes many endemics found nowhere else. However, islands are also highly threatened systems which have suffered hugely disproportionate numbers of extinctions, including the loss of many evolutionary marvels (see Figure 1). For example, for birds, over 80% of known anthropogenic extinctions are of island endemics, and it is likely that we will witness many more island extinctions in the future without concerted conservation efforts.

We now have a rough grasp of the coarse numbers of species that have gone extinct or are threatened with extinction, at least for terrestrial vertebrates. However, much work remains to be completed on understanding how extinctions equate to loss of ecosystem functions, the impacts of poorly-studied extinction drivers (especially regarding poorly-studied taxa) and, crucially, how best to mitigate the threats island biodiversity faces.

With this in mind, this PhD will examine three questions (i) how different taxonomic groups are faring in the current island biodiversity crisis, and how loss of functional roles varies spatially and between taxa (ii) the temporal trajectory of overall island biodiversity, particularly in response to specific extinction drivers, and (iii) how extinction threats on islands can be alleviated through conservation translocations.

Using a number of recently assembled largest-of-their-kind island biodiversity datasets, the project will assess biodiversity change and the potential of different conservation solutions on islands at different spatial and taxonomic scales. First, the project will expand on existing datasets to provide an assessment of how functional diversity has changed on islands as a result of the large numbers of anthropogenic extinctions and extirpations.

Second, the project will involve analysis of a unique 20-year time-series dataset of herpetofauna in the Wallacean biodiversity hotspot (Figure 1) to assess how different metrics of diversity have changed through time in response to different change drivers, including El Nino dynamics. Third, the project will examine the scope for conservation translocations to alleviate anthropogenic pressures on islands, both with regards to replacing lost functions on islands that have experienced extinctions and saving currently endangered island endemics.