Multiple Community Properties Drive Ecosystem Resistance and Resilience to Extreme Climate Events Across Mesic Grasslands

Ecosystem resistance and resilience to extreme climate events is impacted by community properties, including biodiversity. However, the relative importance of species richness, evenness and dominance is debated and is further modulated by global change factors such as nutrient addition. Using nearly 40 years of data from naturally-assembled plant communities at three Long-Term Ecological Research sites, we found that while species richness is important for resistance to extreme dry events, dominance is important for resistance to extreme wet events and evenness is important for resilience under ambient (unfertilized) conditions. Furthermore, nutrient addition alters resistance and resilience indirectly by reducing species richness and increasing dominance. Species richness and dominance are also directly reduced by extreme climate events, which may erode resistance and resilience to future events. Our results show that species richness, dominance and evenness shape ecosystem stability under climate extremes and that fertilization fundamentally modifies biodiversity–stability relationships in mesic grasslands.