ROBERT SIEGEL, HOST:
In many parts of Africa, elephants are threatened by poaching. But in South Africa, they're doing so well that some game reserves say they're overpopulated. Now, many of those reserves are trying to limit elephant reproduction even while some ecologists believe it's the wrong approach. Willow Belden reports.
WILLOW BELDEN, BYLINE: It's a sunny afternoon at Makalali Game Reserve. Giraffes graze at the edge of savannahs, wildebeests gather beneath flat-topped trees and elephants amble through leafy thickets. The reserve is home to all of South Africa's big game species, and visitors pay top dollar to go on safaris here. Amos(ph), a guide at the reserve, stops his jeep near an elephant herd.
AMOS: So the elephants, they eat 24 hours. Wherever you find them, they will be eating.
BELDEN: And sure enough, the elephants wander from tree to tree, wrap their trunks around branches and pull off huge mouthfuls of leaves. Sometimes they even knock over a tree to reach high-up branches. The animals at Makalali seem to be living in the wild, but this is a fenced-in reserve, and the wildlife is closely managed. Most notably, many of the elephants are on birth control. Audrey Delsink is in charge of them. She explains that when elephants were reintroduced to Makalali in the 1990s, their population ballooned.
AUDREY DELSINK: And it's simply because the resources are so phenomenal. You know, elephants hadn't been here for many, many years, and so their vegetation is ideal. In most instances, there's artificial water, and so this just makes for wonderful breeding grounds.
BELDEN: Those conditions are common in South Africa. The elephants all live in parks and game reserves where there's almost no poaching, few predators and abundant water. So the animals live long and multiply quickly. Henk Bertschinger, an expert in veterinary science and animal reproduction from the University of Pretoria, says the problem with that is that game reserves have a finite amount of space.
HENK BERTSCHINGER: And if you don't control the elephant numbers, they're going to destroy the habitat.
BELDEN: Destroy the habitat, as in eat every plant in sight. But controlling elephant numbers is tricky. Sending the animals away is rarely an option because South Africa's parks are full and moving them to other countries would be expensive and a political nightmare. So many game reserves are opting for contraception. Some are vasectomizing elephant bulls. Others, like Makalali, are using birth control on the females. In many cases, they still let the elephants have some babies so as not to mess up herd dynamics, but birth rates are low, and there have been no behavioral changes.
But some experts say tinkering with elephant reproduction is misguided. Rudi Van Aarde heads the Conservation Ecology Research Unit at the University of Pretoria. He says South Africa doesn't have too many elephants, just insufficient space, and he says micromanaging elephant numbers is treating the symptoms of the problem when we should be treating the causes.
RUDI VAN AARDE: When you have a toothache, you don't take a painkiller. You may take it for an hour or two days or whatever, but you go and see a dentist, and you solve the problem.
BELDEN: Van Aarde has pushed for the creation of ecological linkages, which allow elephants to move from one park to another. South Africa now offers incentives to landowners who let elephants travel through their property. They've also eliminated fences between certain parks and surrounding areas. One of those parks is Kruger, a national park the size of Denmark. Sam Ferreira is the park's large mammal ecologist. He points out a tree whose bark has been scraped away and says male elephants sometimes do that kind of damage just because they don't get to be dominant bulls who get to mate until they're in their 40s.
SAM FERREIRA: So what the hell do you do with yourself seriously sexually frustrated for 45 years?
BELDEN: In the past, Kruger managed elephants by killing entire herds. Now, instead of controlling elephants directly, park officials manage the landscape, for instance, by restricting water. Ferreira shows me a clearing with a water trough, fed from a well.
FERREIRA: All right. So this is an example of one of these places where we provide additional water to the animals. This is a functional one still. We've probably closed down about half of the existing ones that we had. There were up to 300 boreholes in the park.
BELDEN: Because the park has taken away some of these boreholes or man-made water holes, elephants have to travel longer distances to find water. As a result, more elephants die during droughts, and fewer elephants are born. Plus, the animals no longer spend all their time in one place.
FERREIRA: So that kind of variability is what we're after because that variability in how elephants use landscapes gives a tree a chance to actually recover.
BELDEN: And indeed, in most parts of Kruger, the vegetation is plentiful, and you have to look closely to see elephant damage. Ferreira says that's an indication that the park service's new approach of restoring natural processes rather than manipulating elephant numbers directly is working. And, in fact, he expects this method to become the new norm for wildlife management not just in South Africa but also in neighboring countries. For NPR News, I'm Willow Belden. Transcript provided by NPR, Copyright NPR.