Several recent studies measuring biodiversity have found significant losses due to global warming and human activity. We know of course, that this has been happening for a while, but its good to be reminded of the path we're headed down. The scale of these species losses is challenging to fathom, and will be challenging to stem.
- In the latest issue of Proceedings of the National Academy of Sciences (PNAS), a group of Stanford scientists found significant amphibian decline in Yellowstone National Park. The researchers found that the number of permanently dry ponds in the northern end of the park increased 4-fold due to changes in the park including rises in annual temperature and decreases in precipitation and snow packs. McMenamin et al found in "Climatic change and wetland desiccation cause amphibian decline in Yellowstone National Park" (doi: 10.1073/pnas.0809090105) that three amphibian species suffered significant declines in numbers since the 1990's. Ambystoma tigrinu decreased by 50%, Bufo boreas decreased by 68%, Pseudacris triseriata; and Rana luteiventris decreased by 75%. The numbers of a fourth species did not decrease -- Bufo boreas however, the scientists found only eggs or juveniles of that endangered species.
- In another PNAS article scientists from Boston University and Harvard found that 27% of the species documented by Thoreau in his studies of Walden Pond in Concord Massachusetts in the 1850's are now gone. The article "Phylogenetic patterns of species loss in Thoreau's woods are driven by climate change" (doi: 10.1073/pnas.0806446105) Another 36% were found in low numbers. The temperatures in Concord rose 4 degress Fahrenheit during that time.
- In the UK, the Department for Agriculture, Food and Rural Affairs found that the number of "breeding pairs of farmland birds" is down 62% due to changes in agricultural processes including the use of chemicals and the decrease in mixed farming. Some species have decreased by more than 85%, and the several are now extinct.
Biodiversity is important for many reasons, some of which are documented in the book: "Sustaining Life: How Human Health Depends on Biodiversity". Eric Chiverian and Aaron Bernstein edit the book, with contributions by 100 scientists. The book takes the perspective that losing species will impact humans in many ways, including incidence of infectious disease, medical research, and food supplies.
