Ape Conservation: protection of refugia should be #1 priority

From the Kansas City Infozine via the GRASP-UNEP facebook page
Not Enough Hours in the Day for Endangered Apes
A study on the effects of global warming on African ape survival suggests that a warming climate may cause apes to run ‘out of time’.

The research, published in Journal of Biogeography, reveals that rising temperatures and changes in rainfall patterns have strong effects on ape behaviour, distribution and survival, pushing them even further to the brink of extinction.

The researchers, from Roehampton University, Bournemouth University and the University of Oxford used data from 20 natural populations to model the effects of climate change on ape behaviour and distribution. The results suggest that rising temperatures and shifts in rainfall patterns alone may cause chimpanzees to lose up to 50% and gorillas up to 75% of their remaining habitats.

This loss of habitat, according to the researchers, is caused by the fact that apes run out of time, as with increasing environmental temperatures apes will have to spend more time resting to avoid over-heating, making some habitats uninhabitable. The study further suggests that chimpanzees will also experience a shift in diet from containing predominantly fruits to leaves.

Lead author Julia Lehmann, from Life Sciences at Roehampton University, said: ‘In reality, the effects of climate change on African apes may be much worse, as our model does not take into account possible anthropogenic effects, such as habitat destruction by humans and the hunting of apes for bushmeat.’

‘Our results highlight that solving the direct local threats, such as hunting and habitat loss due to human activities, may not be sufficient to prevent the extinction of African apes. Ensuring safe havens in optimal habitat must be a critical component of any conservation strategy, lest all current conservation efforts prove to be in vain.’

Reference
Lehman J, Korstjens AH, Dunbar RI (2010) Apes in a changing world – the effects of global warming on the behaviour and distribution of African apes. Journal of Biogeography. doi: 10.1111/j.1365-2699.2010.02373.x

ABSTRACT
Aim
In this study we use a modelling approach to identify: (1) the factors responsible for the differences in ape biogeography, (2) the effects that global warming might have on distribution patterns of African apes, (3) the underlying mechanisms for these effects, and (4) the implications that behavioural flexibility might be expected to have for ape survival. All African apes are highly endangered, and the need for efficient conservation methods is a top priority. The expected changes in world climate are likely to further exacerbate the difficulties they face. Our study aims to further understand the mechanisms that link climatic conditions to the behaviour and biogeography of ape species.

Method
We use an existing validated time budgets model, derived from data on 20 natural populations of gorillas (Gorilla beringei and Gorilla gorilla) and chimpanzees (Pan troglodytes and Pan paniscus), which specifies the relationship between climate, group size, body weight and time available for various activities, to predict ape distribution across Africa under a uniform worst-case climate change scenario.

Results
We demonstrate that a worst-case global warming scenario is likely to alter the delicate balance between different time budget components. Our model points to the importance of annual temperature variation, which was found to have the strongest impact on ape biogeography. Our simulation indicates that rising temperatures and changes in rainfall patterns are likely to have strong effects on ape survival and distribution, particularly for gorillas. Even if they behaved with maximum flexibility, gorillas may not be able to survive in most of their present habitats if the climate was to undergo extreme changes. The survival of chimpanzees was found to be strongly dependent on the minimum viable group size required.

Main conclusions
Our model allows us to explore how climatic conditions, individual behaviour and morphological traits may interact to limit the biogeographical distributions of these species, thereby allowing us to predict the effects of climate change on African ape distributions under different climate change regimes. The model suggests that climate variability (i.e. seasonality) plays a more important role than the absolute magnitude of the change, but these data are not normally provided by climate models.