Global change is altering the diversity of tropical forests

Image: Amazon rainforest. Author: Luis Cayuela (IICG-URJC)

The Institute for Global Change Research (IICG-URJC) has participated in a study based on forty years of tree species records. This work offers a comprehensive view of the evolution of these ecosystems in the face of global change. The research results show that species richness has generally remained stable.

Written by/ Alba Junquera / Irene Vega

For four decades, hundreds of international botanists and ecologists have compiled information on the tropical forests of the Andes and the Amazon. Thanks to this data, the scientific team led by Belén Fadrique of the University of Liverpool has been able to track changes in tree richness and identify the factors driving alterations in tree diversity. This work has also involved the participation of Luis Cayuela, a researcher at the Institute for Global Change Research at URJC.

The scientific team analyzed data from a large region encompassing various areas of South America, home to more than 20.000 tree species. At the continental level, species richness has remained largely stable. However, regional analysis revealed that the Central Andes, the Guiana Shield, and the Central-Eastern Amazon experienced species declines, while the Northern Andes and the Western Amazon showed an increase in the number of tree species. These trends are primarily due to two factors: rainfall and temperature.

These data indicate that forests located in warmer, drier areas with greater seasonality tended to experience decreases in species richness. Conversely, areas with more intact and dynamic ecosystems registered an increase in species. The results of this work have been published in the journal Nature Ecology and Evolution.

Impact of climate change on plant species

Plant species have limited options for surviving climate change: they can shift their distribution as environmental conditions change, or they can adapt to these new conditions. If species cannot shift or adapt, their populations will decline, which could lead to extinction.

As the study's lead researcher, Belén Fadrique, explains: "Our work, which assesses species' responses to climate change, points to profound changes in forest composition and species richness at multiple scales."

For his part, Luis Cayuela points out that "the research team plans to continue its work to better understand the impacts of climate change on tropical tree diversity."

This study involved more than 160 researchers from 20 countries. Numerous South American universities and partners contributed, and it was supported by large research collectives, such as the Amazonian Forest Inventory Network (RAINFOR), the Madidi project, and the PPBio network.