Impacts of climate change are changing grasslands in real time

The time taken for ecosystems to respond to the effects of climate change can vary, but a new study shows that, for grasslands that biodiversity change can happen in almost real time.

“Climate change does have consequences for our ecosystems. It’s going to come sooner or later,” says Yiluan Song, a postdoctoral fellow at the University of Michigan Institute for Data and AI in Society, USA, and co-lead author of the new study in Nature Ecology & Evolution.

“Grasslands are at the faster end of the spectrum.”

The findings could help scientists better understand and predict the impacts of climate change and inform the restoration of grassland vegetation.

“If you want to restore grasslands, you have to ask what types of species you will plant,” says co-lead author Kai Zhu, an associate professor at the University of Michigan School for Environment and Sustainability.

“In order to answer that, you need to at least take climate change into consideration.”

Song, Zhu and their collaborators analysed decades of observations collected across 12 observational studies of grassland communities in the California Floristic Province – a biodiversity hotspot stretching long the west coast of the US.

They determined the climate preferences of various species in the region. Then, they quantified the shifts in plant communities in relation to temperature and precipitation changes also occurring there.

As the climate in the region became hotter and drier, the researchers found that species which preferred those kinds of conditions became more dominant in plant communities.

“The rapid shifts in grassland communities involve not only the gain of some hotter, drier species but also the loss of some cooler, wetter species,” says Song.

“These shifts might have negative consequences such as dominance by non-native species and loss of biodiversity.”

What stood out, the researchers say, was the pace of the ecological change, which was fast and comparable to the observed rate of changes in climate warming and drying.

“Grassland communities may respond more quickly to novel climates, as they consist mostly of short-lived species, which are directly exposed to macroclimate change,” they write in the study,

This is occurring much faster than other terrestrial plant communities dominated by long-lived plants, such as forests, which have been shown to lag in response to climate change and are threatened by growing “climatic debt”.

Although their study focused on a single region, Zhu and Song believe the results will hold in other grasslands.

“I would hypothesise that we may see an even greater response to climate change in other grasslands around the world,” Zhu says.