Noa Lincoln, of CTAHR’s Department of Tropical Plants and Soil Sciences, and Nathanial Wehr, of our Department of Natural Resources and Environmental Management, are co-authors of a new article published in the prestigious journal Science about the importance of earthworms in biosystems—and the necessity for studying these wriggly creatures so we can keep those biosystems healthy.
Soil organisms, including earthworms, are a key component of terrestrial ecosystems. However, little is known about their diversity, their distribution, and the threats affecting them. For this study, researchers compiled a global dataset of sampled earthworm communities from 6,928 sites in 57 countries as a basis for predicting patterns in earthworm diversity, abundance, and biomass. They found high species dissimilarity across tropical locations, which may mean that diversity across the entirety of the tropics is higher than elsewhere.
Climate variables were found to be more important in shaping earthworm communities than soil properties or habitat cover, which suggests that climate change may have serious implications for earthworm communities and for the functions they provide. Any climate change–induced alteration in earthworm communities is also likely to have cascading effects on other species in these ecosystems.
However, local species richness and abundance typically peaked at higher latitudes, displaying patterns opposite to those observed in aboveground organisms. This indicates that what scientists know about how species react to changing conditions may not hold true for those that live underground. The co-authors of the study emphasize the need to integrate belowground organisms into biodiversity research in order to fully understand large-scale patterns of biodiversity. The inclusion of soil creatures may alter what we know about the distribution of biodiversity hotspots and may change conservation priorities. For example, protected areas may not be protecting earthworms. Modeling both aboveground and belowground realms, they explain, will potentially allow a clearer view of the biodiversity distribution of whole ecosystems.