Elephant Squeeze
Shifting climate could help more elephants pack into parks
African savannas aren’t clown cars. Unlike those old Volkswagen Bugs, which can hold a seemingly infinite number of circus performers, only so many elephants can squeeze into a grassland habitat. Still, pinning down that limit, especially as temperatures warm throughout Africa, has been tricky for conservationists. Now, researchers have designed a computer simulation that predicts the future elephant capacity of savannas – and it shows that climate change may be a boon for the large herbivores.
Elephants may be majestic, but they’re not necessarily good for savannas. The trunked animals tear up grasses and short trees at alarming rates, often to the chagrin of smaller herbivores. In the 1960s, fears of rampant over-eating by elephants in Kruger National Park in South Africa convinced land managers to keep herd sizes low. By the 1990s, humans had killed over 14,000 bulls and cows to slim population numbers. Despite these and other drastic campaigns, however, few researchers have explored just how many elephants is too many, says a team of German researchers.
To do just that, the group designed a computer simulation of a fake park much like Kruger. By adding or subtracting elephants from this preserve, they could evaluate the impact on small, woody plants. Then, the team incorporated climate change: They predicted how tree numbers would grow or shrink as temperatures in Africa heated up between 2010 and 2100.
Global warming may not be so bad for elephants, after all, the researchers report in Conservation Letters. Soaring carbon dioxide emissions, hand-in-hand with a roughly 4 degrees Celsius spike in savanna heat, would likely feed the growth of woody plants, they argue. That, in turn, might provide more food for elephants, allowing more animals to squeeze into conservation zones. Savannas able to sustainably accommodate 0.3 elephants per square kilometer today, for instance, could support 4 elephants per square kilometer by 2100.
Based on their results, the researchers say conservationists should take temperature swings into consideration when deciding how many animals a habitat can reasonably hold. The simulation also suggests that Kruger might not be as over-populated as many suspect. The preserve, the team argues, can now healthily accommodate about double the elephants already roaming there. That would mean about 20,000 elephants scrunched into the roughly 20,000 square kilometer preserve–not quite the capacity of a clown car. – Daniel Strain | February 29, 2012
Source: Scheiter S and Higgins SI. (2012) How many elephants can you fit into a conservation area. Conservation Letters. http://onlinelibrary.wiley.com/doi/10.1111/j.1755-263X.2012.00225.x/abstract?systemMessage=Wiley+Online+Library+will+be+disrupted+3+Mar+from+10-13+GMT+for+monthly+maintenance&isLogout=true. DOI: 10.1111/j.1755-263X.2012.00225.x.
Image © Brad White | Dreamstime.com
