Pyric herbivory, scales of heterogeneity, and drought

1. Understanding how extreme drought alters spatial patterns and temporal stability in grassland biomass will become increasingly important by the end of the century when climate model forecasts suggest drought events will occur more frequently. In grassland landscapes where grazing is driven by fire (termed pyric herbivory), temporal stability in aboveground plant biomass at landscape scales typically coincides with greater spatial variability across local communities (time-since fire patches), whereas variability within local communities is associated with lower temporal stability.
2. We assess the robustness of this relationship during one of the most severe droughts on modern record in the southern Great Plains. We use a long-term pyric herbivory experiment to test whether extreme drought: 1) changes patterns of spatial variability in aboveground plant biomass among or within local communities, 2) changes the temporal stability in aboveground plant biomass and the relationship betw...