W Cape a hot spot for plant extinctions

THE Western Cape has been identified as one of the biggest hot spots in the world for plant extinction in a new study published in the journal Nature Ecology and Evolution.

The study focuses on plant extinction rates documented since 1900 until now.

Almost 40 plant species have gone extinct in the province over this time.

This loss forms part of a total of 600 trees, fruit-bearing plant and flowering plant species, that have become extinct over the world at a rate of three species a year.

The province’s extinction rate is 500 times higher than the average global extinction rate, the natural rate at which plants would become extinct.

The researchers used data from the International Union for Conservation of Nature.

“We found that recently described plants are becoming extinct at almost twice the rate of those described before 1900, but at rates almost an order of magnitude lower than for vertebrates.

‘‘The proportions of extinct species from islands (50%) and the Pacific (18%) are significantly higher than expected based on the global distribution of seed plants based on random draws.

‘‘This probably reflects the high proportion of unique species (endemics) in island biotas and their vulnerability to biological invasion,” said the report.

The Western Cape province ranks as the world’s second-worst area of plant extinction, just behind Hawaii which has a total of 79 recorded extinctions to date.

“Our study greatly advances understanding of ongoing extinction in plants and suggests that geography and life form best predict extinction.

‘‘Our study indicates that these caveats can be alleviated through increased study in poorly known, biodiverse areas, and by furthering understanding of the environmental, socioeconomic and temporal relationships between extinction and rediscovery.

‘‘We urge botanists to compile data on search effort, species density, abundance and detectability. Such efforts would improve our understanding of genuine extinctions and help target future conservation action,” read the report.