By admin Although a changing climate affects all ecosystems, its effects may take time to become apparent. It is known, for example, that changes in forest biodiversity lag behind changes in temperature and precipitation in the habitat.
New research from the University of Michigan shows that grasslands respond to climate change in almost real time. In other words, forests accumulate climate debt, while grasslands pay that debt off as they go, say the study’s lead authors, Kai Zhu and Yiluan Song.
“Climate change does have consequences for our ecosystems. They will come sooner or later,” said Song, a doctoral candidate at the Michigan Institute for Data and AI in Society. “Grasslands are on the faster end of the spectrum.”
This work will help the scientific community better understand and predict the impacts of climate change, said Zhu, an associate professor in UM’s School of Environment and Sustainability. The work will also provide key information on restoring vegetation in grasslands.
“If you want to restore grasslands, you have to ask yourself what species you will plant,” Zhu said. “To answer this question, you need to at least take climate change into account.”
The research team reported their findings in the journal Nature Ecology & Evolution.
A team of researchers from several institutions collected data from many years of observations of meadow communities located in the so-called California Floristic Province.
In this biodiversity hotspot that stretches along the US West Coast, the team documented decades-long trends at 12 sites. Scientists found that as the region’s climate became warmer and drier, plant communities became increasingly dominated by species that preferred such conditions.
The team also incorporated results from long-term global change experiments in the region, enabling the group to demonstrate that climate change can drive changes in communities.
“We know that correlation does not imply causation,” Zhu said. “But the experimental data allows us to assign causality.”
The team characterized the climatic preferences or niches for different species in the region. Scientists could then quantify changes in plant communities in direct relation to changes in temperature and rainfall.
This approach led to clear, consistent conclusions across all observational and experimental sites studied, which Zhu and Song say is rare for such ecological studies.
But what stood out even more was the pace of ecological change, they said. It happened quickly and was comparable to the observed rate of climate change. The researchers stressed that this rapid change in plant communities should not be viewed as an adaptation – at least not without further research.
“For me, adaptation creates a positive impression that the system is changing to counteract some of the negative effects of climate change,” Song said. “Rapid changes in grassland communities result not only in the gain of some warmer, drier species, but also in the loss of some cooler, wetter species. These changes may have negative consequences, such as the dominance of alien species and loss of biodiversity.”
Although their study focused on one region, Zhu and Song believe the results will apply to other grasslands, provided they are interpreted in the context of a region’s climate dynamics. For example, if the climate becomes warmer and wetter, species that are more at home in these conditions will likely begin to take over at a rate that matches the changing climate.
“I would hypothesize that we might see an even greater response to climate change in other grasslands around the world,” Zhu said.
Scientists from California Polytechnic State University, Clark College, East Bay Regional Park District, University of Oregon, University of Washington, University of Western Australia and Stanford University also contributed to the study. The team also included members from several University of California institutions, including UC Berkeley, UC Davis, UC Riverside, UC Santa Barbara and UC Santa Cruz, where Zhu and Song began the project.