Lions limit their prey’s response to climate change

Maximum temperature across Africa rises faster than the global average and is already strongly affecting large mammals in African savannas. Historically large mammal species could survive climate change by shifting their distribution ranges towards more suitable climates. However, habitat degradation and human-made barriers, such as fences, increasingly prohibit such range shifts by many larger mammals. Timely evolutionary adaptations to a warmer climate are improbable given the long generation time of large mammals, leaving behavioral adaptations as their number one option.

Now, an international team of scientists provides empirical evidence that carnivores limit the behavioral capacity of their herbivore prey to adapt to warmer conditions. They compared activity patterns for prey species across 32 protected areas with and without lions in South Africa. The study revealed that herbivores face a trade-off between foraging at cooler times (nights) and increased predation risk during these times. In areas without lions, lion prey was much more active during these cooler times than in areas with lions. Consequently, prey experienced a higher temperature during time of activity in areas with lions.

"With increasing temperatures, the window that prey can avoid predation and heat simultaneously is tightening", says lead author, Michiel Veldhuis, of Leiden University in the Netherlands.

The team found strong interspecific differences, where the increase in temperature during activity, to avoid lions, was much larger for species such as gemsbok and zebra than for species such as buffalo and hartebeest.

"The problem is that we currently poorly understand the consequences of this tightening window", says Joris Cromsigt, senior author and leader of the Megafauna & Sustainability (MegaSus) group at the Department of Wildlife, Fish & Environmental studies at SLU. "Some species, such as gemsbok, might be able to avoid lions and tolerate the increased temperature but for others, such as zebra, the increased temperature might carry significant costs".

"This study also clearly shows the benefits of using camera traps as a non-invasive tool to study wildlife as the whole analysis is based on 'by-catch' data from a project aimed at big cats", says Tim Hofmeester, co-author and senior researcher in SLU's MegaSus group.

The authors conclude that predation risk can severely impact the capacity of Africa's herbivores to adapt to a warming climate and stress the need to include predation into climate change predictions, especially for endangered megafauna whose ranges are increasingly restricted by habitat fragmentation.

Contact person at SLU

Joris Cromsigt, Senior Lecturer
Department of Wildlife, Fish and Environmental Studies
Swedish University of Agricultural Sciences, Umeå
joris.cromsigt@slu.se, ph: +46 706760097
https://www.slu.se/en/ew-cv/joris-cromsigt/

The article

The study "Predation risk constrains herbivores' adaptive capacity to warming" was published today in Nature Ecology and Evolution. Co-authors include Guy Balme and Ross Pitman from Panthera, USA, and University of Cape Town, South Africa and Dave Druce from Ezemvelo KZN Wildlife and University of Kwazulu-Natal, South Africa.
https://doi.org/10.1038/s41559-020-1218-2

Press images

(May be published without charge in articles about this press release, please acknowledge the photographer).

Lion. Photo: Tim Hofmeester

Gemsbok. Photo: Tim Hofmeester

Joris Cromsigt. Photo: Susanna Bergström