By John Harris KRRC members are well aware that one of the Center's greatest attractions is its location at the junction of several major ecosystem types, providing Center biologists and visitors with the opportunity to study a wide array of species and ecological processes from a central location. The South Fork of the Kern River is famous for its riparian habitat and high diversity of birds, including many rare and endangered species. Yet within a few miles one can also visit Mojave desert, Great Basin desert, Sierra Nevada montane forests, oak woodland, chaparral, and Central Valley communities, as well as unique transitional communities that occur where these major bioregions come together. Simpson divided the continent into a grid of squares 150 km on a side. He enumerated the mammal species in each square and produced the contour map of mammal species diversity shown here.
Several patterns are evident.
The more dramatic topography of the western portion of the continent provides very high habitat diversity. In fact, this island of high diversity can only be exceeded by traveling to southern Mexico, where one reaches the tropical rainforest biome. Some are montane, but there are also many recognized subspecies that occupy habitats in the foothill region or are restricted to the east side of the Sierra. The southern Sierra in particular is home to a large number of endemic subspecies of mammals, and thus it represents a critical reservoir of genetic diversity. Of the endemic species or subspecies of mammals in the Sierra, about 25 are restricted to the central and southern Sierra.