Study offers new insights on biodiversity in South Africa

Two UConn ecologists are challenging the common perception that tropical rain forests are the most biologically diverse regions on the planet.

John Silander Jr., a professor of ecology and evolutionary biology, and doctoral student Andrew Latimer say the scenic, wildflower-covered hills of the Cape Floristic Region of South Africa contain as much plant diversity as many of the world’s tropical rain forests.

The patterns of diversity in this South African region, however, differ fundamentally from the more familiar diversity patterns of the Amazon.

Their findings were published in the Sept. 9 issue of the journal Science. [Go to the Science article]

The researchers also suggest that some biodiversity hot spots may be more vulnerable to the effects of climate change and global warming than others and may require their own specially-tailored conservation strategies.

“When people think of the world’s biodiversity hot spots, or areas with extremely high concentrations of different species, they tend to picture tropical rain forests like the Amazon,” says Latimer, the article’s lead author. “Our study shows that the Cape Floristic Region of South Africa as a whole is just as rich and diverse as a similarly-sized piece of the Amazon, but an ecological tour through that region would look completely different.

Latimer says in the Amazon, “there are a staggering number of different tree species in close proximity to each other, but a number of those species keep reappearing” throughout the region.

By contrast, in South Africa’s Cape Floristic Region, there are a series of small, Mediterranean-climate communities known as fynbos shrub lands, he says. “Those mini-shrub lands, which are separated from each other by drier lowland areas, each essentially contain a unique set of plants. Plants found in one area in abundance may be scarce or not present at all in the next area.”

Latimer and Silander attribute the different diversity pattern found in the Cape Floristic Region of South Africa to seed dispersal rates that are about 100 times lower than in the Amazon. In the fynbos shrub lands, they note, many plant seeds are carried by ants, which don’t travel more than a few miles, as opposed to birds and large mammals which typically disperse seeds widely in the Amazon.