Will There Still Be Great Apes at the End of the 21st Century?

Written By: Matt Brunette
Category: From The Field, Great Apes

A group of scientists at Oxford Brookes University recently issued a shocking message. After closely scrutinizing the most recent data, researchers concluded that many ape populations may be extinct by the end of the 21st century.

Their disappearance is part of what’s referred to as the sixth mass-extinction event in which three-quarters of all species could disappear within the coming centuries. While mass-extinction events have certainly occurred before, the current rate of extinction is faster and affecting more species than previously. Moreover, the anticipated, and dramatic, decline in biodiversity is man-made.

After years of decline, most of the world’s primate species now reside in only four countries: Brazil, Madagascar, Indonesia, and Democratic Republic of Congo (DRC), and each is undergoing major environmental changes and face similar human and conservation challenges.

In DRC, habitat loss, hunting pressure, and disease are some of the biggest contributors to population declines in the resident species: chimpanzees, bonobos and gorillas. Bushmeat hunting and the illegal wildlife trade are especially prevalent in Africa with hunting and trapping affecting 54% to 90% of primate species. In eastern DRC, forests are logged to make room for mining precious minerals such as coltan, tin, gold, and diamonds. Where there are miners there is also hunting for bushmeat and the wildlife killed includes endangered eastern lowland gorillas and chimpanzees.

All chimpanzee subspecies (Pan troglodytes) are at-risk and continue to decrease in numbers. Where once there were millions of chimpanzees across Africa, today it is estimated that chimpanzees are down to 172,000 to 300,000.

Gorillas are critically endangered and at more immediate risk of extinction. Eastern lowland gorillas (Gorilla gorilla graueri), endemic to the eastern forests of DRC, have undergone a drastic population decline of 77% between 1995 and 2015. It is now thought that only 4,000 remain in the wild.

Great Apes and Climate Change

Another important factor in the decline in great apes is climate change. As climate change impacts ecosystem composition and changes habitat through increased variability in seasons, weather, precipitation, and temperature, wildlife is forced to migrate to survive. In many cases, primates leave protected areas bringing them into closer contact with people, increasing human-wildlife conflict, the spread of disease, and hunting.

The combination of these human actions and climate change are particularly effective at pushing primate species to the brink of extinction. Chimpanzees, like the other great apes, have a relatively limited range and slow reproductive cycles. Young chimpanzees remain with their mothers for several years and reach reproductive maturity after 10 to 12 years of age. This makes them particularly vulnerable even when population losses are small and more susceptible to extinction.

Primates are important to a healthy ecosystem

Primates are integral to a well-functioning ecosystem.  As seed dispersers, great apes contribute to ecosystem structure, biodiversity and sustainability. Research has shown that in the absence of seed dispersing primates, plant species display decreased gene flow and diminished diversity which can negatively impact forest resilience and plant species survival.

The loss of primates from forests has a more direct impact on people— 48% of plants whose seeds are dispersed by primates in western Cote d’Ivoire and 42% in Uganda have economic or cultural utility to local communities. Without primates, we lose an ecologically and economically important species that benefits people around the world through ecosystem services that improve forest health and disperse seeds. Without primates, we also lose our closest living relatives.

Preventing the extinction of chimpanzees, gorillas and other great apes will require extensive efforts on multiple fronts. Continued conservation work that focuses on both environmental and socio-economic benefits are important to tackling the complexity of the issues driving primate population declines.

The day-to-day decisions we make at work and at home also have an impact. By consuming less and by making environmentally conscious consumer decisions, we can reduce our impacts on tropical forests and reduce our contributions to the factors driving extinction.