"If you put a boundary around a piece of land and install some bored park guards and that's all you do, the park will eventually die," said Janzen, DiMaura Professor of Conservation Biology in Penn's Department of Biology. "It's death from a thousand cuts."
Writing July 25 in the journal Nature, the researchers report that the protected forest areas are not serving as the "arks" that some conservationists had hoped for. Four-fifths of the areas included in the survey had experienced some declines in health. About half of the areas had suffered more serious losses to biodiversity.
...environmental conditions and activities occurring outside of the reserves were strong predictors of how biodiversity inside the boundaries fared. Logging, declining forest cover and increasing fires outside the protected areas tended to pull down the health of the reserves themselves. Such losses were rampant...
Thanks Ruth for telling me about the study.
I learned about biodiversity in my studies - I am very interested in this topic.