Poaching is not the only reason rhinos may go extinct

The ongoing effects of climate change may cause rhinos to go extinct unless adaptation measures are implemented, according to new research.

While rhino conservation has primarily focused on poaching, less is known about how the rhino population will survive should temperatures continue to increase throughout the 21st century.

The research:

A study conducted by two researchers (Hlelowenkhosi S. Mamba and Timothy O. Randhir, 2024) at the University of Massachusetts considers the human-induced threat of climate change to rhinoceros populations. Their research focuses on the national parks of eastern and southern Africa, including South Africa (Kruger), Namibia (Etosha), Kenya (Tsavo West), Zimbabwe (Hwange), eSwatini (Hlane Royal), Botswana, Zambia, and Tanzania. As of December 2021, these regions were home to 92% of the white and 80% of the black rhino populations. In the study, two climate change scenarios are used to predict the effect temperature and precipitation changes will have on each of the rhino populations. The study used the Intergovernmental Panel on Climate Change (IPCC’s) Representative Concentration Pathways (RCPs) 4.5 and 8.5, with atmospheric CO2 concentrations of 650 and 1370 ppm, for the years 2055 and 2085.

Rhinos and increased temperatures:

Previous research suggests more than a million species are vulnerable to extinction by 2050 due to climate change. Accelerated temperature increases will further exacerbate this. Species’ survival often depends on their ability to adapt or migrate. For the rhino, migration is a challenge because of human settlements. Rhinos also lack the bodily processes to release heat, i.e. they do not sweat. While rhinos can increase wallowing, water consumption and resting in the shade – higher temperatures will threaten these natural cooling techniques.

Rhino occurrences are greatest between temperature ranges of 12–24.1°C. Black rhinos tolerate a wider temperature range compared to their white counterparts. White rhinos prefer more moderate temperatures. 

Findings:

Average monthly temperatures in Africa have increased by 0.5–2°C over the past century. A further increase of 2°C is expected throughout the continent by the middle of the 21st century.

Under the RCP 4.5 scenario, all the (examined) national parks will see average temperature increases of ± 0.2°C by 2055 and ± 0.3°C by 2085. Furthermore, under this RCP 4.5 scenario, the probability of rhino occurrence at these national parks decreases to zero even with high mitigation, at mid-century.

Under the RCP 8.5 scenario, the average temperatures will increase by ± 0.3°C by 2055 and ± 0.6°C by 2085. The probability of rhino occurrence at all (examined) parks, if things continue as they are, is zero, by the late twenty-first century.

As temperatures increase throughout the century, conditions in these national parks will become increasingly unsuitable for both species. Predictions indicate white rhinos will be affected earlier than black rhinos. Thus, climate change will profoundly impact the probability of the occurrence of both black and white rhinos in southern Africa.

Solutions:

The survival of rhinos depends on human interventions. Interventions can include enabling habitat resilience through the modification of landscapes. Conservation efforts must include increased access to shade and water, wallowing mud pits, and misting stations during periods of peak temperatures.