Preserving Biodiversity in Areas of Conservation
Although parks and preserves are treasured by the general public and conservationists alike, two recent studies by UC Berkeley researchers show that our mere presence near conservation areas may be to blame for their decline.
The first study, led by Justin Brashares, assistant professor of environmental science, policy, and management, and George Wittemyer, a postdoctoral researcher and a National Science Foundation research fellow, focused on rates of human population growth in nearly 306 rural protected areas in 45 African and Latin American countries. Their study showed that the rate of population growth along the borders of protected areas was two times higher than that found in nearby rural areas.
“Many parks are hotspots for ecosystem services and goods, such as open water, good soils for agriculture, bushmeat, fish and timber,” Brashares explains. Although these resources are helping communities near the edges of the preserves flourish, the dramatic population increase in these same areas may threaten the biodiversity the preserves seek to sustain, as researchers found that high human population growth correlates with higher rates of deforestation.
Wittemyer suggests that “implementing relatively simple policies, like locating development projects in regions where human pressures will have less impact on biodiversity, rather than placing them directly on the edges of the parks,” is a better alternative.
An unrelated study of native carnivore populations in San Francisco Bay Area parks and preserves, led by Sarah Reed, postdoctoral scholar in UC Berkeley’s department of environmental science, policy and management, showed surprising findings, according to Adina Merenlender, senior author on the study.
Reed counted mammalian carnivore droppings in parks that allow public access and compared the number to droppings found in similar private preserves. She discovered that native carnivore droppings were five times lower in public parks. Reed’s evidence showed that carnivores were not just avoiding trails used by humans—they were completely avoiding public parks. Reed’s findings are all the more important as recent surveys indicate that the number of U.S. day-hikers has increased 800 percent from 1960 to 2000. We may do better, Reed suggests, by allocating certain areas of a park for conservation only.
Though the two studies focus on different aspects of conservation and development in Africa, Latin America, and California, their findings show that human presence in natural surroundings has a measurable and far-reaching effect on entire ecosystems. Despite our best intentions, it seems the dueling desires to both protect and reap the benefits of natural resources may be too great a burden for Mother Nature to bear.