It’s a tough time to be an African elephant. Despite an international ban on ivory trading, the animals are being slaughtered for their tusks at a greater rate today than before the ban was enacted in 1989. At the same time, scientists are learning that the traumatic effects of the deaths of close relatives — especially for female elephants — may echo throughout the fragmented families for decades.
“These solitary females just finally had daughters — they’re trying to raise families. And they are just going to get mowed down again,” says Kathleen Gobush, lead author of a new study that examines the long-term effects of poaching.
In the decade before the ivory ban, the number of African elephants plummeted from roughly 1.3 million to fewer than 600,000. There was a hue and cry from the public and, for a few years, the ban seemed to keep things in check. But then funding for wildlife law enforcement dropped and roads for logging and drilling opened vast, previously impenetrable tracts of the forest to poachers.
“Poaching is the worst in history right now,” says Samuel K. Wasser, director of the Center for Conservation Biology at the University of Washington in Seattle. Before the ban, about 7.4 percent of animals were killed for their tusks each year. Estimates suggest that the annual rate is now 8 percent, which could bring African elephants to extinction by 2020.
Scientists are documenting poaching’s lasting effects and, at the same time, making headway with forensics research that may help thwart poachers.
“Elephants are extremely important to ecosystems in Africa. They manipulate habitat, they keep savannahs, savannahs,” Wasser says. Implications for ecosystems and ecotourism aside, “when you reduce the elephant population it is hugely disruptive to their social structure and physiological health — and it takes a huge amount of time to recover.”
Two new studies document the toll of those disruptions. One, published online in Conservation Biology and based on Gobush’s thesis work in Wasser’s lab, looks at the family structure, stress hormone levels and reproductive output of more than 200 female elephants in Mikumi National Park in Tanzania. This area lost an estimated 75 percent of its elephants to poaching before the ivory ban. Adult males and large adult females were the poachers’ first targets. Typically, 6 percent of populations are tuskless, due to a genetic quirk. That number has been boosted by selective poaching — today in Mikumi about 15 percent are tuskless.
Elephants have intricate social networks, dominated by female matriarchs, explains Joyce Poole, who studied the Mikumi population before the ban. The females and young males generally travel and live in groups. When group members do spend time away from each other, reunions are marked by “greeting ceremonies,” which entail throat rumbles, rapid ear flapping and a clanging of tusks.
The older females — African elephants can live to about 65 — are “the glue that holds the family together,” says Poole, the research and conservation director for ElephantVoices, which has projects in Kenya and Sri Lanka. Faced with a threat, younger elephants turn to the matriarch to determine if they should fight or flee. Daughters typically stay with their moms their whole lives.
Gobush examined more than 100 of these family groups; about 59 percent had an old matriarch. The families were roughly distributed among six populations, each centered around a watering hole. Four areas were designated high-risk, having been poached heavily in the past. Those areas were farthest from park headquarters but close to park boundaries. Two populations lived in areas designated low-risk.
Analysis of fecal hormone levels and DNA revealed that female elephants in groups lacking a matriarch or closely related relatives had higher levels of stress hormones known as glucocorticoids. The spiked hormone levels were especially pronounced in elephants dwelling in areas where past poaching was greatest. Females from these disrupted groups were also less likely to be pregnant or have an infant.
“If you are in a high-risk area and you lack family — that solid group unit — that’s when you’re in trouble,” says Gobush.
The findings suggest disruption of a family group is a chronic stress condition for African elephants, and can be further exacerbated by other disturbances, such as a lack of rain.
The new work also suggests that, “If the family is disrupted it is going to be 30 years before the family is intact again,” says biologist Susan Alberts of Duke University, who calls the results “very well-integrated.”
A separate study by Charles Foley of the Wildlife Conservation Society, and colleagues, investigated the survival of elephant calves during extreme drought. Fewer calves died in groups with an experienced mother. Old matriarchs appear to give a family group a survival edge, perhaps by remembering the location of distant water in hard times, the researchers reported in August in Biology Letters.
Elephants have a “tremendous interest in and awareness of death,” Wasser says. They will spend an inordinate amount of time sniffing bones, passing over non-elephant skeletons. Researchers have noted the similarities between teenage elephants and teenage humans experiencing post-traumatic stress disorder. A team of researchers, including Poole, have described bizarre behavior, such as killing rhinoceroses, by young male elephants who, due to poaching, had no older male role models. This unusual aggression ceased when older male elephants were introduced to the area, Poole and colleagues reported in a 2000 Nature paper.
Also, in a study of a park heavily affected by poaching, elephant-against-elephant aggression accounted for 90 percent of deaths, compared with 6 percent in unstressed areas, the team wrote in 2005 in Nature. These hyperaggressive males were probably orphaned by poaching, and witnessed the death of close relatives, the researchers wrote.
The dismal outlook of today results from a confluence of factors. Illegal wildlife trade has metastasized in this era of global trade, where customs officials typically inspect a mere 1 percent of shipping containers, Wasser says. Yet compared to drugs or weapons, wildlife trafficking is a low priority for law enforcement and thus low-risk for criminals.
A booming economy in China has led to increased demand for symbols of wealth, exemplified by the rising popularity of ivory “hankos,” personalized signature stamps that are akin to a family seal. Ivory knife and gun handles have become popular in Japan and some U.S. cities. Since 2004 the wholesale price of ivory has more than quadrupled from roughly $200 per kilogram to $850 per kilo in 2007, and retail has been as high as $6,500 per kilo, says Wasser
“Law enforcement can’t win this fight — it is hopeless. Enforcement will admit that without batting an eye,” says Wasser.
A new analysis by Wasser and colleagues focuses on pinpointing the origins of several large seizures of tusks, hankos and ivory scraps. Using DNA from more than 600 reference samples, the analysis assigns the DNA to a geographic region in Africa. The work suggests that rather than collecting from a hodge-podge of sites, poachers hit the same hot spots over and over again, Wasser and colleagues report in August in Conservation Biology. Tracing the ivory back to source countries highlights areas for enforcement to target and forces these countries to acknowledge poaching problems, says Wasser.
Given the threats to African elephants, it may come as a surprise that some areas are considering culling, or killing elephants to decrease their numbers for wildlife management. This tactic has recently been proposed to deal with the elephants in Kruger National park, South Africa’s biggest wildlife preserve. Until recently the park was completely fenced in, artificially concentrating the elephants, says Rudi van Aarde, director of the Conservation Ecology Research Unit at the University of Pretoria in South Africa.
Years of data collection on the dynamics of elephant populations suggest an alternative: connecting disparate areas via tracts of land allows the elephants room to roam. This approach may do more to control the impact of elephants than lowering their numbers with guns. These “megaparks” would allow elephants to disperse, mimicking the ecological circumstances in which they normally function.
“At first people said you must be crazy,” says van Aarde. “Now they are saying tell us how to implement this.”
Backstory : Poaching Hotspots New work by Samuel K. Wasser and colleagues may help stymie poachers by pinpointing the origins of seized ivory shipments. The analysis uses more than 600 reference samples of elephant DNA and incorporates the fact that elephant populations living near each other have more similar DNA than populations that are farther apart. The resulting genetic map suggests that poachers are hitting the same spots over and over again. Click on the map below to see an enlarged version.
