Williams-Climate-change-refugia-for-terrestrial-biodiversity_0

1.2.2 Case study 2: Pleistocene stability and diversity of herpetofauna
Evolutionary refugia are expected to be hotspots of both species and genetic diversity.
Identifying these areas will help target areas needing further biological research or
conservation action. Evidence of the location and behaviour of refugia through past
climate change is also important for improving our understanding the likely response of
species distributions to anticipated climate change and the effectiveness of refugia in
mitigating loss of biodiversity over the coming century.
Stability of climate since the last glacial maximum (LGM) has been shown to relate
strongly to current endemism of species (Graham et al. 2006, Davies et al. 2009) and
genetic variation within a range of species (Carnaval et al. 2009, De Mello Martins
2011) via its effect on the distribution of vegetation types. Here, we assessed the effect
of a changing paleo-climate over the past 120 000 years on the distribution of rainforest
on Australia’s eastern seaboard. From this we identified the areas which have been
most climatically stable for rainforest and therefore may function as evolutionary refugia
for rainforest specialist taxa.
Infraspecific diversity provides a sensitive measure of persistence, because even
where species are widespread, they may contain locally endemic lineages which imply
local persistence of the species in particular areas. We modelled the distribution of
independent lineages within rainforest lizard species, and identified their centres of
endemism as indicators of places that have functioned as evolutionary refugia,
retaining local diversity through late Pleistocene climate cycles.
1.2.3 Case study 3: Drought refugia in monsoonal Australia
Our objective here is to make use of the latest remote-sensing technology and satellite
imagery to identify ‘greenspots’ across the Australian continent. These greenspots
represent areas of higher photosynthetic activity in each bioregion. Given that
photosynthesis is ‘thirsty work’, these greenspots point to places in the landscape that
are wetter than their surrounds. Typically, these greenspots will not be the result of
broader climatic variables, but reflect instead peculiarities of topography, geology, and
soil that allow these areas to accumulate and store water. Thus, these greenspots
represent locations where microclimate is decoupled from the regional situation, and
therefore likely represent important seasonal refugia, as well as refugia against
extreme drought events.
1.2.4 Case study 4: Using conservation planning tools to identify regional
refugia
Here we demonstrate the use of conservation planning software (Zonation) as a means
of identifying regional refugia. We used current and future modelled species
distributions for 191 terrestrial vertebrates from the Australian Wet Tropics Bioregion to
prioritise the landscape for current and future conservation. Areas ranked highly for
both current and future conservation are likely to function as refugia, more so if these
areas are in close proximity.
6 Climate change refugia for terrestrial biodiversity