Rhinos in a warming world.

By April 13, 2022Editorial

Indian Rhino, Chitwan National Parl, Nepal. Image: Natalia Maroz/Shutterstock

From 2008 through 2021, Kruger National Park lost 5,569 rhinos to poaching. But the figure is likely a lot higher than that—Kruger is an immense tract of land, and many crime scenes would have gone undetected in its 7,500 square miles of wilderness.

This appears to be borne out by the results of rhino population surveys. In 2011, South African National Parks (SANParks) reported that the Kruger’s White Rhinos had seemingly leveled off at approximately 10,600 animals. But then, in early 2022 came the shocking revelation that Kruger’s White Rhino population was a mere 2,607—South Africa’s premier conservation area had lost 75 percent of its White Rhinos in no more than a decade. While some of these missing rhinos would undoubtedly have been undetected poaching victims, could there have been another element at play, threatening the beleaguered species?

Poaching pressure to feed the demand for rhino horn in Asia is surely the most pressing challenge to rhino survival in the Kruger National Park and is likely to remain so for some time to come. But Dr. Sam Ferreira, SANPark’s large-mammal specialist scientist, and colleagues contended that there was indeed another driver contributing to the rhinos’ woes. They pointed to unpredictable climate conditions as the culprit.

Over 2015 and 2016, Kruger’s rainy season failed. Grass cover was much reduced, and as white rhinos are almost exclusively grazers, they would have suffered from a lack of food, both in quantity and quality. In these circumstances, increased deaths from natural causes were to be expected.

Furthermore, the situation would have been exacerbated for females as their physical condition would have impacted their ability to produce offspring. So, while we might hope that poaching is to be brought under control, the virtual certainty of increasing temperatures and extreme swings between drought and flood will pose a possibly even greater threat to the species’ medium and longer-term survival.

Of course, the vagaries of climate change will not be limited to Kruger. We are told the impact of climate change will be significant throughout sub-Saharan Africa, so all existing White Rhino populations could well be at risk. Possibly those on private land might be better off if given additional feed, but such interventions would be impracticable at any scale in vast game areas such as national parks.

Kruger’s comparatively small Black Rhino population has also been hard hit by poaching. From an estimated 427–586 in 2017, the population fell to only 202 in 2021—a loss of some 55 percent over three years. Fortunately, however, Black Rhinos seem to be less affected by drought, and again it is food that plays a major part. Black rhinos are browsers and therefore have access to a far wider diversity of trees, shrubs, and other non-grass herbaceous plants. In hard times at least some of these food sources would likely persist, probably in sufficient amounts to prevent any deaths or slump in birth rates due to the poor condition of females.

While it would be wrong to say that an increasingly warmer, drier climate would be especially beneficial for Black Rhinos, some are already adapted to such conditions. This is particularly so for the Southeastern Black Rhino (Diceros bicornis bicornis), the most numerous subspecies in Namibia’s desert and semi-desert terrain.

D. b. bicornis was once prolific throughout the western part of South Africa, into Botswana, and north of Namibia into Angola. Hunting and land-use changes put paid to that situation. By the mid-1800s, the subspecies was extinct in South Africa, and neither did it survive in Angola or Botswana. South Africa now has a small reintroduced population, mainly in the Addo Elephant National Park in the Eastern Cape, but Botswana’s even smaller reintroduced population has been all but annihilated in the recent wave of poaching.

In Asia, Nepal has a commendable, albeit somewhat controversial, record in combatting the poaching scourge, with only one or two losses in recent years. As a result, the county’s Indian Rhino population has grown steadily, reaching 752 at the end of 2021. Nevertheless, since 2014, more unexplained rhino deaths due to “natural causes” have been puzzling conservation scientists. From 2015 to 2017, an average of 20 mysterious losses were recorded.

There are several considered opinions as to why this is happening. For example, the ecology of the Rapti River meandering along the northern border of Chitwan National Park has changed due to the construction of dikes. This has caused silting, which has destroyed many of the wallows favored by the rhinos. Competition for the remaining wallows and other resources is fierce, so fighting, sometimes to the death, is not uncommon.

This conflict is understandable given the relatively small size of Chitwan—it’s about a twentieth of the size of Kruger—coupled with its high rhino density. Additional challenges such as human-wildlife conflicts, invasive alien species, and habitat degradation have also played a part, as have the extreme monsoon events of recent years. Heavy flooding has taken its toll on humans and wildlife alike, and rhinos are no exception. The floods have pushed the rhinos westwards into less suitable habitats, and many have been swept away by raging waters, either drowning or suffering severe injury. The situation is not very different from Kaziranga in India’s Assam Province, where human-induced land degradation, conflict with wildlife, and monsoon flooding have also had serious consequences.

Extreme monsoon seasons, of course, point to climate change, something that is attracting the attention of Ganesh Pant, a young scientist at the University of Southern Queensland. Pant has found that the Nepalese rhinos are likely to be “moderately impacted” by the changing climate. The country’s rhinos live in the Terai grasslands and riverine forests of southern Nepal, a third of which could become unsuitable for rhinos in the next 50 years, Pant said. Wetlands drying up, floods, fires, invasive alien vegetation, and increasing woody plants will all affect the rhinos’ habitat. As a result, Pant is pushing for new sanctuaries to expand the range of rhinos in Nepal and take some of the pressure off Chitwan.

Of course, the most threatened of all the extant rhinos are the forest-dwelling remnants of the Javan and Sumatran Rhinos. Their only surviving populations teeter at the edge of oblivion, each with fewer than 80 individuals. The Javan Rhino, once arguably the most widespread and diverse of all the rhinos, is now confined to one location at the western tip of Javan, while the Sumatran Rhino lives in sanctuaries and tiny, scattered wild groups on the islands of Borneo and Sumatra.

When numbers get this small, the challenges to survival are enormous. Impossible, in fact, without significant and long-term human assistance. And as if this is not enough, there is growing evidence that global climate change is significantly altering the forest ecosystems in which they live and will continue to do so in the future. As elsewhere, general warming coupled with extremes such as drought, severe storms, and wildfires can significantly affect species and their distribution and the very fabric of the forests themselves.

Rhinos are big, tough, and robust mammals that have survived a remarkable evolutionary span of some 55 million years. But paleontological evidence points to times in this long history when altering climates have posed severe challenges to their line. For example, late in the Miocene epoch, about seven million years ago, drying and cooling across the continents presented animals and plants with significant challenges to their survival. A number didn’t make it, including many rhinos. Earlier in the Miocene, rhino diversity and distribution had reached its zenith when more than 50 genera roamed the earth. But drought and cold took their toll, and only a few made the cross over into the Pliocene about 5.3 million years ago.

More recently, we have the example of the extinct Woolly Rhino, Coelodonta antiquitatis, which we know from DNA studies is most closely related to the Sumatran Rhino. This shaggy beast evolved in the icy wastes of northeastern Asia, surviving until the arrival of humans.

With justification, it was long thought that hunting put paid to the Woolly Rhino’s existence about 14,000 years ago. But recent findings suggest rapid climate change to be a major factor in its demise. Its thick, matted coat was well adapted to the cold. Even its long horn, thinner and more blade-like than those of living rhinos, was suited for survival—scientists suggest it was used to sweep away the snow to expose the tufts of greenery below.

Then, a sudden extreme warming event took place, and with it, more rain and more snow, possibly too deep for the rhinos to reach their food. Prior to this time, DNA studies show that the Woolly Rhino population was stable and diverse, notwithstanding the presence of humans, only dipping rapidly somewhere between 18,500 and 14,000 years ago. The warmer, wetter climate would have also altered the rhino’s habitat, with its grazing grasslands becoming more shrubby and wooded.

Quite possibly, it was the combination of hunting and climate change that drove the Woolly Rhino into oblivion. History appears to be repeating itself yet again, another lesson perhaps in how quickly a rapidly altering climate coupled with our planet-altering habits can precipitate a survival tipping point for many species.

Maps showing the historical distribution of rhinos reveal an awful truth. No more than 200 hundred years ago, the rhinos of Africa and Asia were still abundant, staggeringly so. In Africa, south of the Sahara, only the Congo Basin was devoid of rhinos, while the Asian species spread from northwestern Pakistan through to China and south to almost all of the Malaysian Archipelago. Now we have only pathetic remnants in little more than islands of habitat. Almost everywhere, rhinos are already extinct. What chances then are there for their survival.

Obviously, we have to find solutions to the poaching wars. We cannot allow mutilated rhinos to continue dying for the stupid and senseless price we put on their horns. But we also need to find solutions to the troubles that lie ahead regarding climate change. The latest report of the Intergovernmental Panel on Climate Change tells us, as it does with increasing urgency year after year, that we have less and less time to act to avoid the worst consequences.

“We are on a fast track to climate disaster … we are on a pathway to global warming of more than double the 1.5°C limit agreed in Paris … Climate scientists warn that we are already perilously close to tipping points that could lead to cascading and irreversible climate impacts.” These are the words of U. N. Secretary-General Antonio Guterres who says, accusingly, that “some Government and business leaders are saying one thing, but doing another. Simply put, they are lying. And the results will be catastrophic.”

So while political and business leaders dither and prevaricate, criminally so, what steps, other than fighting the rhino horn war, should we be taking?

Given what we know about the inevitability of severe climate change, one action is imperative. We have to repeat what Ian Player did in the 1960s—find new homes for rhinos where they once roamed. The more rhinos we can reintroduce to historical locations, the greater the chance some will take root and thrive.

Happily, this is already happening. Witness the recent moving of rhinos from South Africa to Rwanda, the success of the Black Rhino Range Extension Program, and the Indian Rhino Vision 2020. All are uplifting examples of positive conservation intervention in action. Programs that prove we can make a difference.