杏吧原创

Global warming could rapidly threaten grasses, including wild relatives of staple foods such as wheat and rice that provide half of all the calories consumed by humans.

A new study looking ahead to 2070 found that climate change was occurring thousands of times faster than the ability of wild grasses to adapt.

This doesn鈥檛 directly threaten food crops, but wild relatives provide a source of genetic diversity for, say, creating disease-resistant strains of crops.

While the research cannot predict what might happen to world food supplies as a result, the authors warn of 鈥渢roubling implications鈥�.

Starvation warning

The new research looked at the ability of 236 grass species to adapt to new climatic niches 鈥� the local environments on which they depend for survival.

Faced with rapid climate change, species wedded to a particular niche can survive if they move to another region where conditions are more suitable, or evolve to fit in with their altered surroundings.

The study found that the predicted rate of climate change was typically 5,000 times faster than the estimated speed at which grasses could adapt to new niches.

Moving not an option

Moving to more favourable geographical locations is not an option for a lot of grass species because of limits to their seed dispersal and obstacles such as mountains or human settlements.

鈥淲e show that past rates of climatic niche change in grasses are much slower than rates of future projected climate change, suggesting that extinctions might occur in many species and/or local populations,鈥� wrote the researchers, led by John Wiens, from the University of Arizona in the US.

鈥淭his has several troubling implications, for both global biodiversity and human welfare.鈥�