Wreathed Hornbill (Rhyticeros undulatus). Hornbills are important seed dispersers in many forests yet they are often targeted by hunters. Click image for more photos of hornbills. (Photo by R. Butler)
By Rhett Butler | Last updated July 27, 2012
Humans have long hunted wild game from forests, but over the past 50 years commercialization of killing has triggered a rapid increase in wildlife depletion. Hunting and poaching cause damage to the rainforest ecosystem by removing species key to the system's functioning. The loss of a certain single species can mean extinction for many others.
Hunting of seed dispersers and pollinators can influence the structure of a forest. According to research from Central Africa, heavy bushmeat hunting alters forest composition by favoring small-seeded trees over large-seeded, leading to lower tree diversity of trees that have big seeds.
The wildlife harvest takes a staggering number of animals: every year in the Brazilian Amazon alone, where 9.6 to 23.5 million mammals, birds, and reptiles are harvested. The annual harvest in the tropical forests of Africa may be 6-12 times that amount, since illegal poaching in Africa is rampant to provide meat for poor rural and urban dwellers.
Average wildlife harvesting rates of large mammals (>1 kilogram adult body mass) in tropical forests are about 6.0 animals per square kilometer per year in
Southeast Asia (2 studies), 17.5 animals in Africa (2 studies), and 8.1 animals in Latin America (5 studies) according to data derived from J. Robinson and E. Bennett, Eds., Hunting for Sustainability in Tropical Forests (Columbia University Press, New York, 1999). Chart and photo of a young gorilla in Gabon by Rhett A. Butler.
These rough estimates, showing that millions of animals are killed each year in Africa, Asia, and the Amazon for subsistence hunting and the bushmeat trade, are extrapolated from J. Robinson and E. Bennett (1999) data, forest cover figures from the U.N. Food and Agricultural Organization for 2005, and numbers in J. Robinson and K. Redford, Eds., Neotropical Wildlife Use and Conservation (University of Chicago Press, Chicago, IL, 1991);. The numbers include mammals, birds, and reptiles. Estimation, chart and photo of a red howler monkey in Colombia by Rhett A. Butler. Please note that these are only rudimentary estimates -- there are presently no reliable projections for the number of animals hunted each year.
In Asia, tiger populations have been dramatically reduced due to widespread habitat loss and Chinese demand for traditional medicinal products made from tiger parts. Endangered Sumatran elephants are increasingly poached for their ivory and could go extinct within 50 years at present hunting rates. In Indonesia, where there is a thriving black market for endangered wildlife, orangutans are suffering from both habitat loss and the illegal trapping of baby orangutans for the pet trade. Typically, mother orangutans are killed since they refuse to abandon their young.
In Brazil, Colombia, Nigeria, Madagascar, and other countries, the collection of wild animals for the pet trade takes its toll on local animal populations. Although such collection can be done in a sustainable manner, it rarely is. Reptiles are the fourth biggest commodity after drugs, diamonds, and weapons in the world smuggling trade, but losses are quite high: less than 10 percent of all animals exported illegally make it alive to their final destination—usually a small, dirty terrarium.
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INTRODUCTION OF ALIEN SPECIES
While not directly responsible for deforestation, the introduction of foreign plants and animals can cause severe damage to rainforests, especially in delicate ecosystems like islands. These feral species bring new diseases and compete with local species.
The bird life of Guam and Hawaii has suffered from the introduction of alien species [Invasive species news]. In the case of Guam, the culprit was a snake, while in Hawaii the mosquito and domestic chickens were responsible for the decline of native birds. Since the arrival of the Polynesians, at least 62 endemic bird species have disappeared from Hawaii. It is even more startling that Hawaii has more alien plant species than native ones. Alien weeds can choke out endemic plants, especially under disturbed forest conditions like agricultural clearing.
Additionally, alien species can wipe out endemic keystone species that play an important role in the ecosystem, like pollinating certain tree species. The elimination of such an endemic species can spell the end for the tree species and a host of other dependent plant and animal species.
Climate change is expected to increase the number of alien species in some ecosystems.
- Why are tigers endangered?
- How can alien or invasive species impact the environment?
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Gabon steps in to help protect elephants from ivory poaching at Central African Republic site
(05/18/2013) Gabon has agreed to help battle poaching in protected areas in the Central African Republic following an elephant massacre at a renowned World Heritage site, reports the Wildlife Conservation Society (WCS).
NGO: conflict of interests behind Peruvian highway proposal in the Amazon
(05/16/2013) As Peru's legislature debates the merits of building the Purús highway through the Amazon rainforest, a new report by Global Witness alleges that the project has been aggressively pushed by those with a financial stake in opening up the remote area to logging and mining. Roads built in the Amazon lead to spikes in deforestation, mining, poaching and other extractive activities as remote areas become suddenly accessible. The road in question would cut through parts of the Peruvian Amazon rich in biodiversity and home to indigenous tribes who have chosen to live in "voluntary isolation."
Elephants massacred for ivory in Central African Republic
(05/10/2013) Dozens of elephants have been slaughtered in the Dzanga Bai World Heritage Site in the Central African Republic just days after conservationists warned about an impending threat from the movement of 17 heavily armed poachers. The massacre occurred at a site renowned as 'village of elephants', where tourists and scientists have for decades observed wild elephants congregating at a large clearing to feed on minerals.
17 poachers allegedly enter elephant stronghold in Congo, conservationists fear massacre
(05/07/2013) Local researchers and wildlife guards say 17 armed elephant poachers have gained access to Dzanga Bai, a large waterhole and clearing where up to 200 forest elephants visit daily in the Central African Republic (CAR)'s Dzanga-Ndoki National Park. WWF, which works in the region but has recently evacuated due to rising violence, is calling on the CAR government to rapidly mobilize its military to stop another elephant bloodbath in central Africa. Elephants are being killed across their range for their ivory, which is mostly smuggled to East Asia.
A Tale of Two Elephants: celebrating the lives and mourning the deaths of Cirrocumulus and Ngampit
(05/07/2013) On March 21st, the organization Save the Elephants posted on their Facebook page that two African elephants had been poached inside a nearby reserve: "Sad news from the north of Kenya. Usually the national reserves are safe havens for elephants, and they know it. But in the last two weeks two of our study animals have been shot inside the Buffalo Springs reserve. First an 18 year-old bull called Ngampit and then, yesterday, 23 year-old female called Cirrocumulus (from the Clouds family)."
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