Earth News Journal 19: Rapid Mammal Extinction in Fragmented Forests

The destruction of tropical forest habitats is contributing to a rapid decline in mammal species, according to a recent article in The New York Times.

In recent years, conservation biologists have studied a vastly destroyed forest habitat in Thailand – an area aiding them with their studies on mammal extinction, while symbolizing the negative effects of human interactions in the tropical forest ecosystem.

The Thailand government constructed a dam across the Khlong Saeng River in 1987, “creating a 60-square-mile reservoir” in the process. When the “Chiew Larn reservoir rose, it drowned the river valley, transforming 150 forested hilltops into islands.”

Over the last two decades, biologists have been frantically tracking the diversity of mammals on these human-made islands, only to discover devastating results.

David Woodruff of the University of California at San Diego conducted species counts on the islands between 1992 and 1994; he noted a significant difference between the mainland species and the island species, even with only five years separating the dam’s construction from a wholesome habitat. In 2012, when Dr. Gibson returned to the Thailand forested islands, he only discovered one species on the majority of the islands, the Malayan field rat – a species not originally found on the island ecosystem. Regrettably, “only on a few islands did some species still cling to existence.”

The diversity of mammals found in the mainland forests was the same as in the initial surveys. Dr. Gibson replied, on the rate of these depleted diversities, “Our results should be a warning. This is the trend that the world is going in. No one expected to see such rapid extinctions.”

Dr. Primm, the president of Saving Species and professor of Duke University, agreed with Dr. Gibson, saying that the “fast pace of extinction in forest fragments gives an urgency to conserving the large swaths of topical forest that still remain.”


I find it quite disheartening that these conservation biologists have arrived on the scene of Thailand just a little too late. To think that the government of Thailand concocted this dam, without consulting ecological professionals, is very telling of the time period and of the location. I would hope that if a dam were to be erected in the United States, the Environmental Protection Agency would deduce all possible outcomes, should the dam impact the surrounding environment, before construction, not decades after the fact. Although, I do think it wise that these named conservation biologists are utilizing one critical mistake, in hopes of preventing future mammal extinctions that would have occurred as rapidly as in Thailand. Humans must learn from failure – trial and error. It’s the only way we know how to improve our society. I’m encouraged that this rapid mammal extinction in the tropical forests of Thailand is attracting the attention of biologists across the globe – it means that scientists are currently addressing this issue and hopefully compiling a variety of solutions to similar future problems. One solution I pose is that all political governments have a dutiful environmental team that helps influence decisions about the country that would favor both human beings and the surrounding habitats.  

Zimmer, Carl. “In Fragmented Forests, Rapid Mammal Extinctions.” New York Times (blog). N.p., 26 Sept. 2013. Web. 21 Oct. 2013.

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