UCT study finds global patterns in plant diversity

A STUDY by a group of UCT researchers has found global patterns of the plant biodiversity in the Cape Floristic Region .

The study investigated the plant diversity in the mega-diverse Cape Floristic Region (CFR) and tested predictions of the two main hypotheses for the existence of the diverse areas.

One hypothesis found that areas are diverse because the environment has been quite stable leading to reduced extinction of species.

The other hypothesis found that areas are diverse because they offer more ecological opportunities due to topographic conditions, rainfall seasonality and productivity.

These findings reflect the importance of protecting nature and its extraordinary biodiversity against the threat posed by climate change.

Professor Res Altwegg of UCT’s department of statistical sciences and co-author of the study said he was always amazed at the spectacular plant diversity right outside his office window, and this study suggests that climatic stability has been important for this diversity to form.

“I worry that this diversity might be especially vulnerable as the climate is beginning to change.”

The researchers found that the CFR’s richness could be largely explained by the fact that the region had not experienced major changes in its climate over the past 140 000 years, showing that history is an important driver of biodiversity.

“We chose to investigate the CFR partly because this Mediterranean-climate region provides an excellent opportunity to simultaneously investigate the ecological and historical drivers of diversity.

“The flora is the richest extra-tropical flora in the world, comprising 9 383 species (68% endemic) in just 90 760km².”

Jonathan Coville of UCT’s Department of Statistical Sciences and a research fellow at the South African National Biodiversity Institute (Sanbi) and also lead author of the study, said: “In South Africa we are fortunate to not only have incredible biodiversity but also a uniquely detailed knowledge of where these plants are found, thanks to the collections at Sanbi.

“This rich resource enabled us to pull together an interdisciplinary team from South Africa and the UK to tackle one of the most challenging questions in ecology.

“It highlights how important international collaborations are to the future success of South African research and the conservation of its biodiversity.” |