Investigating Life

investigating life

How do geographic area and isolation affect the biogeography of life on Earth?

At the opening of the chapter, we asked how geographic area and isolation might affect the biogeography of life on Earth. You have seen that this question is highly relevant at different spatial scales—from whole continents to small islands—and also over different time scales—from millions of years to months. Because the spatial and temporal scales at which biogeographic patterns manifest themselves are so wide and interconnected, it can be hard to test theories of biogeography with experiments that are large and long enough to be meaningful. The Biological Dynamics of Forest Fragments Project (BDFFP), an experiment conducted in the most species-rich region of the world, and at arguably the largest scale ever attempted, offers support for theories proposed nearly 200 years ago by explorers such as Humboldt, Wallace, and Darwin, who hypothesized that the distribution of species on Earth is highly influenced by the geographic area and isolation those species have experienced. The question remains, in the case of the Amazon Basin, whether species will ultimately adapt to the changing biogeographic landscape or become a casualty of an extinction event that would be unrivaled in human history.

Future directions

One of the major findings of the BDFFP is the importance of connectivity in maintaining species diversity. Management and permitting of forest clearing are focusing on creative ways to connect forest fragments by taking advantage of existing landscape features to increase connectivity of disturbed habitat. For example, in Amazonia strong laws exist to prohibit clearing forest along rivers and steep slopes, providing strips of land that can serve to connect fragments around newly cleared land.