The world is currently undergoing an anthropogenically-induced extinction crisis, with rates of species loss far exceeding natural background levels. The human impacts on global ecosystems include habitat loss and fragmentation due to land-use change for agricultural or grazing areas, introductions of non-native species, pollution and anthropogenic climate change. This necessitates a systematic and efficient approach to conserving what is left of global biodiversity. Spatial prioritisation is essential because we do not have adequate resources to secure the future of all species. But how can we prioritise if we don’t know how threats will impact the ecosystems? Or how do we prioritise among the millions of species on the planet, when only so few of them are known? How can we ensure that species will persist in spite of the direct and indirect threats caused by people? Advances in climate modelling and geographic information systems have improved our understanding of climate change and new techniques have been developed to quantify its impact. Impacts of climate change include habitat loss and fragmentation, which affect species’ persistence. So if we are able to spatially identify where species have higher/lower probabilities of extinction we could select areas for conservation that deliver efficient or sufficient conservation.
Besides identification of threats and their impacts when prioritising, having a clear and well-defined conservation goal is crucial. One can prioritise for maximising the representation of species in an area- but since we don’t know the number or the distribution of all the species in the world we will miss many of them, especially cryptic species. Therefore designing conservation measures that focus on ecological and evolutionary processes that have given, and continue to give rise to species is needed. This is especially important in a world where the environment is rapidly changing. Yet, identifying the processes that give rise to biodiversity and promote its long term persistence can be time consuming and prohibitively expensive at any meaningful scale. This has increased the widespread use of surrogates for evolutionary processes, i.e. facets of the environment that can be relatively easily measured and closely correlate with the evolutionary process themselves.
In this thesis I investigate simple ways to identify the vulnerability of ecosystems to climate change, the problems of taxonomic uncertainty when selecting areas for conservation and how evolutionary processes can be included in conservation planning in archipelagic systems. Systems with naturally disjunct distributions are thought to be especially vulnerable to anthropogenic threats. However they are rich in endemic species and hence valuable for conservation. Species in fragmented habitats may behave as metapopulations which allow the estimation of their extinction risk and genetic analyses. My thesis is divided into the following four data chapters. The first two (chapter two and three) investigate the prediction of impacts while the last two (chapter four and five) are actual prioritisations.
In chapter two I develop the first spatial maps of the vulnerability of Tropical Montane Cloud Forest to future climate change. Then I analyse the location of current protected areas under those future scenarios and how this will impact the loss of species. In chapter three, I model Mexican Tropical Montane Cloud Forest future distribution changes, from 2030 to 2080 and analyse how the habitat loss and fragmentation, and climate change will impact on the persistence of Mexican cloud forests species. In chapter four I look at the consequences of different approaches of spatial prioritisation for cryptic species. I will find priority areas for conservation for frogs of the Craugastor genus in Mexico using three different approaches: International Union for Conservation of Nature range maps, expert taxonomist and genetic analyses. Finally, in chapter five, I explore the use of simply obtained geographic surrogates to prioritise islands to manage for conservation. To do so I assessed two silvereye species (Zosterops flavifrons and Z. lateralis) of the Vanuatu archipelago with different regional genetic structures.
In conclusion, my thesis finds different simple approaches that could be easily applicable in different regions of the world when prioritizing for conservation, enhancing the probability of persistence of threatened species and ecosystems.