The variable effects of climate change on different subspecies of giraffe (genus Giraffa)

Anthropogenic climate change is one of the biggest threats facing the natural world. It may disproportionately affect tropical, slow-reproducing species, especially in Africa. Giraffes have experienced a ~40% population decline in 30 years, potentially as a result of climate change, but there is very little literature dealing directly with this threat. We used locality data for eight of nine extant giraffe subspecies and maps of bioclimate variables, ecoregions and altitude to construct species distribution models. We projected giraffe distributions in the present and for six possible future scenarios for 2070, based on three general circulation models (CCSM4, HadGEM2-ES and MIROC-ESM) for two threat levels (2.6 and 6 W/m2 radiative forcing respectively). Our models performed well. Ecoregions seemed to be the most important factor affecting all giraffe subspecies save the reticulated giraffe, which was more affected by mean diurnal temperature range. Our future projections showed variable impacts of climate change. Three subspecies, the Angolan, Rothschild’s and Masai giraffes, may suffer significant declines in suitable habitat area, depending on the precise ways the climate changes. Other subspecies were less affected and may even expand their ranges. Knowledge of these differences in risk will help us conserve giraffes more effectively in future.