What Impact Have Humans Had on Ring-Tailed Lemurs?

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Ring-tailed lemurs naturally exist only on the African island of Madagascar. Humans first arrived on the island nearly two thousand years ago, making it one of the last landmasses of any significant size to acquire a human population. Despite their late arrival, many changes in the island’s environment made by humans have deeply impacted the behavior and health of ring-tailed lemurs. At least 16 species of lemur have gone extinct since the arrival of humans, and all extant species are considered threatened or endangered.

Agriculture

Since humans arrived, most of Madagascar’s original forests have been cut down for crop-growing or pasture purposes. According to Dr. Kathleen Muldoon of Dartmouth University, people have eliminated or degraded some 90 percent of the forests of Madagascar that ring-tail and other lemur species call home. The slash-and-burn technique is the one most often used. Rice is a staple food for the Malagasy people, and trees are cut down and burned to clear land. The ashes from the burned trees provide beneficial nutrients for rice, but these nutrients are depleted quickly, forcing farmers to clear more land to sustain production.

Logging

Certain trees native to Madagascar, particularly rosewood and ebony, are desired worldwide for use in furniture and other products. These trees are a key part of the ring-tailed lemur's habitat and frequently grow in protected areas. A military coup in 2009 resulted in a surge of illegal logging, as the government was either unwilling or unable to enforce protective environmental regulations. On March 12, 2013, numerous Malagasy species of rosewood and ebony trees were added to the Convention on International Trade in Endangered Species of Wild Fauna and Flora, making the import and trade of timber from these trees illegal in signatory nations.

Hunting

Lemur fossils found with slash marks from ancient iron butchering tools provide indirect evidence of some of the earliest human impact on ring-tailed lemurs: they were killed for food. Despite traditional Malagasy taboos against the killing or eating of lemurs, an influx of foreign workers for illegal logging and other labor has resulted in a surge in hunting of ring-tailed lemurs and other lemur species. In addition to being killed for a growing bush meat market, lemurs are also captured and sold in the illegal pet trade.

Introduction of Invasive Species

When humans migrated to Madagascar, they brought domestic dogs to guard livestock and domestic cats to fend off rodents and other pests. Feral populations of dogs and cats now roam the island, often preying on ring-tailed lemurs. According to Dr. Michelle Sauther of the University of Colorado, feral dog feces and animal remains show evidence of predation on ring-tailed lemurs, which is bolstered by eyewitness accounts. Close proximity to humans and their domestic animals exposes ring-tailed lemurs to new diseases and also forces them to alter their behavior. Non-native plants damage the health of ring-tailed lemurs as well. For example, one introduced plant species is known to cause chronic hair loss in ring-tailed lemurs that consume it.

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