Biogeographically distinct controls on C3 and C4 grass distributions: merging community and physiological ecology

摘要: Aim C4 photosynthesis is an adaptation that maintains efficient carbon assimilation in high-light, high-temperature conditions. Due to the importance of C4 grasses for and surface energy fluxes, numerous models have been proposed describe their spatial distribution forecast responses climate change. These often rely on broad climatic predictors (e.g. temperature precipitation) but fail integrate other ecologically relevant factors like disturbance competition, which may modify realized C3/C4 grass distributions. Here, we present a combined evaluation contribution ecological We consider multiple biogeographic regions North America using multisource database over 40,000 vegetation plots. Location The conterminous United States (USA). Methods We identified comprehensive pool literature used information theoretic criteria select primary predictor C3 Subsequently, best model was with fire, tree cover) regression framework tested within eight regions. Results Surprisingly, grass-dominated communities across USA exist largely C3- or C4-dominated states. Transitions between dominance were explained by integrated precipitation varied according region. For some regions, Eastern Temperate Forests, local comparable strength broad-scale abundance. Main conclusion Local drivers ways manifest at regional scales. In example, abundances are maintained below expectations where cover creates light limitation above frequent fires reduce cover. Thus, factors, vary among contribute large-scale disequilibrium.