Climate change has undeniable global consequences on ecosystems and ecological community compositions, but the reason why some communities are better able to withstand the effects of climate change than others can be a mystery.
Researchers analyzed community composition changes and diversity over half a century in a new scientific study that included nearly all North American bird species. Bird communities with more species diversity and a wider range of functional traits consistently saw less drastic changes in their community makeup as a result of climate change.
For instance, if a community had birds of prey, insectivores, and seed-eaters rather than simply birds from one feeding guild, it was more protected from the detrimental effects of climate change, according to Emma-Liina Marjakangas, Ph.D., the study’s principal researcher from the University of Helsinki.
Community-level diversity functions as a buffer against negative climate change consequences, particularly during the winter, which has seen the most climatic warming across the Northern Hemisphere. Biodiversity, on the other hand, played a lower role during the breeding season. Indeed, previous research has demonstrated bird communities change faster in the winter than in the summer, which describes this pattern.
The ability of a species to change breeding and wintering locations is determined by habitat and food availability. For example, grassland species have migrated northwards more slowly than forest passerines like the American robin or habitat generalists like the mourning dove, according to the University of Helsinki Senior curator Aleksi Lehikoinen.
Functionally diversified bird communities maintain ecosystems by dispersing plant seeds, controlling pests, and even pollinating flowering plants. Climate change alters the composition of these vital bird communities, jeopardizing their ability to offer ecosystem services.
The findings add to the awareness that biodiversity protects ecosystem functioning and that the biodiversity and climate crises must be addressed concurrently to avoid multiplicative impacts, says Marjakangas.
The research was published in the international journal Scientific Reports and is based on a community science database covering all of North America from 1966 to 2016.
Marjakangas, E. L., et al. (2022) Effects of diversity on thermal niche variation in bird communities under climate change. Scientific Reports. doi.org/10.1038/s41598-022-26248-1.