Will faster-than-expected plant evolution alter global warming forecasts?

New research has addressed the question of whether faster-than-expected plant evolution, a less unlikely situation than might be thought, can prevent forecasts related to global warming from coming to pass.

The rapid evolution of traits that affect growth in dominant marsh plants may lead to ecosystem-level changes in the structure and function of coastal wetlands, including their resistance to sea level rise. This has been determined in an investigation carried out by Megan Vahsen’s team, from the University of Notre Dame in the United States.

The results of this study suggest that evolutionary processes may play an even larger role than previously thought in regulating ecosystem function and should be taken into account when predicting ecosystem responses to climate change.

In coastal marshes (which tend to have low plant diversity), the dominant plants often act as ecosystem engineers, contributing to soil development and sediment accumulation, which has allowed the marshes to keep pace with the variations in sea level over thousands of years.

Furthermore, the rapid growth of these plants, combined with the low decomposition rates of the soils of the coastal marshes, makes the ecosystem capable of storing large amounts of carbon.

A marsh. (Photo: Mary Hollinger/NODC/NOAA)

However, while more and more studies show how traits and growth of dominant marsh plants contribute to these processes, the role that both trait variation and evolution play is often overlooked in models. that predict the response of ecosystems to environmental changes that are taking place.

According to the authors of the new study, this is due, in part, to a lack of empirical studies showing that evolutionary processes are important drivers of ecosystem change.

In their research, Vahsen and colleagues focused on 16 genotypes of the dominant marsh sedge, Schoenoplectus americanus, using “resurrected” plants from generation-spanning seed banks and neighboring marshes. The study revealed considerable and ecologically significant heritable variation, as well as rapid evolution in the allocation and distribution of below-ground biomass.

These findings, when incorporated into a coastal marsh ecosystem model, altered predictions of carbon sequestration and accretion from the soil surface in coastal marshes.

According to the study authors, the results suggest that these plants can evolve at a rate and magnitude that can have considerable impact on ecosystem processes, including resilience to sea level rise and the storage potential of atmospheric carbon. “Therefore, failure to account for heritable variation and rapid evolutionary change in ecosystem models could mischaracterize the role of organismal responses in ecosystem resistance to environmental change, thereby could systematically alter predictions at the ecosystem level.”

The study is titled “Rapid plant trait evolution can alter coastal wetland resilience to sea level rise”. And it has been published in the academic journal Science. (Source: AAAS)