March 5, 2002: Our Closest Relatives Are Disappearing

Update 7: March 5, 2002-3

Our Closest Relatives Are Disappearing

Janet Larsen

After more than a century of no known primate extinctions, scientists recently confirmed the disappearance of a subspecies of a West African monkey. The loss of this monkey, known as Miss Waldron's red colobus, may be a harbinger of future losses of our closest evolutionary relatives.

Out of some 240 known primate species, 19 are critically endangered, up from 13 in 1996. This classification refers to species that have suffered extreme and rapid reductions in population or habitat. Their remaining numbers range from less than a few hundred to, at most, a few thousand individuals. If their populations continue to shrink at recent rates, some species will not survive this decade. This group, according to the World Conservation Union's 2000 IUCN Red List of Threatened Species, includes 8 monkeys from Brazil's Atlantic rainforest, where 97 percent of the forest has been lost, 2 apes and a monkey from Indonesia, 3 monkeys from Viet Nam, 1 each from Kenya and Peru, and 3 lemur species from Madagascar.

At the endangered level, the IUCN's next degree of threat, there are 46 primate species, up from 29 in 1996. These species face a very high probability of extinction, some within the next 20 years. An additional 51 species are listed as vulnerable. These primates have slightly larger populations but still may disappear within this century. Critically endangered, endangered, and vulnerable species together total 116, or nearly half of the 240 some primate species.

When the last Ice Age ended 10,000 years ago, baboons outnumbered humans by at least 2 to 1. If all non-human primate populations were counted together, including the large populations of some of the smaller species, they dwarfed the human population. Now that has changed. The development of agriculture allowed for rapid human population growth, and about 2,000 years ago, humans-numbering 300 million-became the most abundant of the primates. By 1930, the human population of 2 billion likely outnumbered all other primates combined.

Today, at 6.1 billion and climbing, we are threatening the survival of many of our primate cousins, including our closest living relatives, the chimpanzees and bonobos, with which we share over 98 percent of our genome. The other apes are quite close to us as well, not only genetically, but also in observed behavior. Yet with the 300,000 human babies born each day exceeding the total population of the great apes, even our evolutionary proximity may not prevent us from eradicating our near-kin.

While humans now inhabit every corner of the earth, most other primates exhibit strong endemism, meaning that a species is restricted to a particular area. Almost three quarters of all primates live in just four countries: Brazil, the Democratic Republic of the Congo (formerly Zaire), Indonesia, and Madagascar. In each of these countries, forest cover is decreasing. Because habitat loss is a danger to 90 percent of threatened primates, their concentration in a few countries greatly increases their vulnerability.

In Indonesia, diverse forests and wild inhabitants have suffered from logging fueled by corruption and political instability. Within the past decade, deforestation rates doubled, claiming almost 2 million hectares each year. As deforestation rates doubled, orangutan numbers dropped by half. By 2005, the country faces the loss of all lowland forest from Sumatra, and thus the extinction of the critically endangered Sumatran orangutan, among many other species. The Borneo orangutan, after suffering from logging, hunting, and the catastrophic fires of 1997, is not likely to survive beyond 2010 if current trends continue.

Our closest relative, the bonobo, is endemic to the Congo, a country plagued by civil war and occupation by foreign military and rebel groups. Along with many other primates in the region, the slow-breeding bonobo has seen a rapid decline. In 1980 there were close to 100,000 bonobos; now there may be fewer than 10,000.

Although the civil war has created millions of human refugees and may have elevated the demand for meat from wild animals (bushmeat), the resulting sluggish economic development may have slowed logging in the Congo, the country containing half of Africa's remaining tropical moist forests. If political stability returns, tree cutting could increase several fold in the next few years, accelerating what could be the first great ape extinction.

Gorilla populations have dropped to dangerously low levels, largely from illegal commercial bushmeat hunting. Fewer than 325 mountain gorillas exist, and all are in one subpopulation spanning Rwanda, the Congo, and Uganda. The rarest, the Cross River Gorilla, is limited to only 150 to 200 individuals scattered among several lingering subpopulations on the Cameroon/Nigeria border region.

In parts of West and Central Africa, hunting is an even greater threat than forest loss. There the bushmeat trade, consisting primarily of forest antelope, pigs, and primates, is worth over $1 billion a year. In areas where social turmoil has ravaged traditional economic activities, and the average annual family income is less than $100, the lure of earning $300 to $1,000 each year as a hunter has enticed many. Logging and, to a lesser extent, mining companies have penetrated forests, with their settlements increasing bushmeat demand, while their roads facilitate hunting.

Exploitative hunting is not profitable in the long term, however, because wild populations, especially those of the large and slow-reproducing apes, are soon decimated. Over 1 million tons of wild meat is consumed annually in the Congo Basin, almost 6 times more than the forests' sustainable yield. Commercial hunting has emptied forests that were once full of animals.

Though rural communities have long subsisted on wild animals and other forest foods, with up to 60 percent of their protein coming from bushmeat, most bushmeat from this region is now consumed in cities. Almost half of the 30 million people living in the forested regions of Central Africa are city-dwellers who are being fed with bushmeat from collapsing wildlife populations. As cities grow and bushmeat hunting accelerates to meet rising demand, it is estimated that hunting could eliminate all viable African ape populations in fewer than 20 years.

To save other primates from being lost in what is considered the earth's sixth major extinction event, resources are needed to curb illegal logging and hunting. Illegal logging has ruined vast stretches of original primate habitat. Much of the bushmeat hunted comes from protected areas, and international trade in primates is already unlawful under the Convention on International Trade in Endangered Species. But when enforcement is lacking, illegal practices continue.

Large wilderness blocks of biologically rich areas can be converted to new parks that take into account the needs of wildlife and human populations. Ecotourism endeavors can be used to support primate conservation, and hunters can find alternative income in park protection work once they realize that live animals can be much more valuable than dead ones.

Understanding ourselves better-our biology, psychology, and sociology-depends in part on understanding our closest living relatives better. If we destroy them, we may never fully understand ourselves.

FOR ADDITIONAL INFORMATION

Russell Mittermeier, "Biodiversity Issues Affecting Primates," keynote paper from The Apes: Challenges for the 21st Century, Brookfield Zoo, Chicago, May 2000.

John F. Oates et al., "Extinction of a West African Red Colobus Monkey," Conservation Biology, v. 14, no. 5, 5 October 2000, pp. 1526-1532.

Gay Reinhartz and Inogwabini Bila Isia, "Bonobo Survival and a Wartime Conservation Mandate," keynote paper from The Apes: Challenges for the 21st Century, Brookfield Zoo, Chicago, May 2000.

Species Survival Commission (Craig Hilton-Taylor, compiler), 2000 IUCN Red List of Threatened Species (Gland, Switzerland, and Cambridge, UK: World Conservation Union-IUCN, 2000).

John Tuxill, "Death in the Family Tree," World Watch, September/October 1997, pp. 13-21.

Carel P. van Schaik, "Securing a Future for the Wild Orangutan," keynote paper from The Apes: Challenges for the 21st Century, Brookfield Zoo, Chicago, May 2000.

David S. Wilkie and Julia F. Carpenter, "Bushmeat Hunting in the Congo Basin: An Assessment of Impacts and Options for Mitigation," paper from The Apes: Challenges for the 21st Century, Brookfield Zoo, Chicago, May 2000.

LINKS

The Apes: Challenges for the 21st Century, Brookfield Zoo Conference, May 2000
http:/www.brookfieldzoo.org

Bush Meat Crisis Task Force
http:/www.bushmeat.org

Conservation International
http:/www.conservation.org

Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES)
http:/www.cites.org

IUCN Red List of Threatened Species
http:/www.iucnredlist.org/

Jane Goodall Institute
http:/www.janegoodall.org

The Species Survival Commission of the World Conservation Union http:/www.iucn.org/themes/ssc

TRAFFIC
http:/www.traffic.org/bushmeat

United Nations Environment Programme Great Apes Survival Project (GRASP) http:/www.unep.org/grasp