Loss of Biodiversity Makes Humans Sick

The sixth great extinction is underway, many conservationists warn, meaning that as many as 50 percent of animal species on earth may vanish by the end of the century. The numbers are staggering and undeniably tragic but what do they mean for the planet's human population? According to a new study, the massive loss of biodiversity may increase the number of disease-causing organisms, making sickness a much more common occurrence.Sam Scheiner, a researcher with the National Science Foundation,  Global change is accelerating, bringing with it a host of unintended consequences...species extinctions may lead to increases in disease incidence for humans, other animals and plants. The problem, Scheiner's study shows, is that when habitats are fragmented, the species most deeply effected are those that act as buffers for disease. Those that thrive happen to be the best carriers of pathogens. One example was based on research conducted at the Cary Institute of Ecosystem Studies in Millbrook, New York. As forest habitat in this region was lost, the population of opossum, a strongly buffering species, dwindled as the numbers of white-footed mice—a species responsible for the spread of Lyme disease increased. As a result, instances of Lyme disease among humans in this area have increased. Researchers don't know why this correlation exists, but their work clearly shows that preserving natural habitats is the best way to prevent the effect. Andrew Dobson, a researcher at Princeton University who coauthored the study, explained When biological diversity declines, and contact with humans increases, you have a perfect recipe for infectious disease.a