Two decades of data on plant communities and weather from the LTER Main Cropping Systems Experiment show that extreme dry and wet years reduce species richness (the number of species) but increase evenness (how evenly abundant the species are). Because richness and evenness also increase long-term stability and resistance to extreme precipitation events, these changes to communities might have long-lasting effects on the resilience of plant communities to the increasingly variable precipitation patterns expected in the future.
While the focus of climate change is often on warming temperatures, precipitation patterns are also expected to shift in the future. There are likely to be more extreme events, including more droughts and more highly wet periods. How plant communities might respond to these events, and whether they remain stable in the face of such changes, is still fully unknown.
Scientists at the KBS LTER are now in a better position to answer questions about grassland resilience to climate change based on new research from graduate student Sierra Pérez (PhD Candidate with Jennifer Lau, Indiana University).
Her research used two decades of records collected from the LTER Main Cropping Systems Experiment on primary productivity of early successional grasslands, combined with long-term meteorological data on precipitation events. Using this information, she was able to evaluate how plant community properties relate and respond to precipitation.
The results show that responses of plant communities to wet and dry periods influence their response to future disturbances. This is driven by the makeup of the plant community, such as the abundance of dominant species like goldenrod, and the overall the number of species in the community – called richness. While some of these properties might make communities more stable in the long-term and promote a feedback loop of resilience within the community, changes to other community properties like species richness might lead to feedbacks that reduce resilience.
This work highlights the value of the LTER in maintaining long-term ecological and meteorological data. The plant communities within the LTER provide an ideal background to learn about community reactions to major shifts in climate variables. By learning about ecological responses from the past several decades, we can better predict changes to plant communities in the coming decades.