Background
The effects of climate change are predicted to cause substantial shifts in habitat, which could increase the extinction risk of species that are already experiencing extreme habitat loss. Here, we identify low risk areas that are likely to be important corridors for Grauer's gorillas that are responding to habitat shifts due to climate change. By linking climate model projections with habitat models for Grauer's gorillas, we can assess where corridors need to be conserved before they are lost to other land uses.
Building the Model
We used a habitat suitability model to project the future extent of the three main habitat types that Grauer’s gorillas prefer (dense moist tropical forest, montane forest, and submontane forest). Our future projections are based on 5 climate models to represent the inherent uncertainty in climate projections. We projected these models to 2050 and 2070 for 2 climate change scenarios, RCP 4.5, a intermediate emission scenario and RCP 8.5, a worst case scenario.
Model ResultsRCP 4.5
Under the intermediate emission scenario (RCP 4.5) the climate is predicted to warm by about 2 degrees Celsius. Our results forecast an initial increase in forest habitat, which is largely caused by the expansion of dense moist tropical forest. However, after the initial increase in forest habitat, we see a long term overall decline in forest habitat toward the end of the century as temperature increases. RCP 8.5 Under the high emissions scenario (RCP 8.5) total forest habitat increases. This increase in habitat area is entirely driven by the expansion of dense moist tropical forests, which is likely a result of increased rainfall in the area under the worst case emissions scenario. Low Risk Areas These are regions where the future extent of habitat overlaps with current habitat areas under all 4 climate scenarios. Climate resilient forest habitat should be a priority for conservation because it will continue to be viable habitat in the future and it can act as a bridge for gorillas to move through in response to habitat shifts. |
Areas of Grauer’s gorilla habitat predicted to be most resilient to climate change. Overlap areas for all three forest types are combined to show the total extent of gorilla habitat predicted to be resilient to climate change. The areas shown in orange on the map represent zones of forest habitat that are most resilient to climate change. |
Takeaways
The climate model suggests that under all future climate scenarios, optimal Grauer’s gorilla habitat is likely to experience shifts in range that will reduce the availability of submontane and montane forests in Kahuzi-Biega National Park. Such extensive loss of habitat could be catastrophic for the long-term persistence of the species if they cannot disperse across the landscape. Ensuring that areas of future suitable habitat outside of the park are available for dispersal may be critical to prevent the extinction of this sub-population.