Persistence and turnover in desert plant communities during a 37‐yr period of land use and climate change

摘要: Understanding long‐term changes in ecological communities during global change is a priority for 21st‐century ecology. Deserts, already at climatic extremes, are of unique interest because they projected to be ecosystems most responsive change. Within 500‐km² landscape the Mojave Desert, USA, we measured perennial plant 100 sites three times (1979, 2008, and 2016) 37 yr evaluate six hypotheses community These encompassed shifts measures (e.g., diversity, cover) species elevational distributions, biotic homogenization, disproportionately large highest elevations, relationships between turnover species’ responses disturbance drought, that environmental refugia moist topographic positions) would receive warming drying. Most changed temporally, such as density (species/600 m²) increasing 23% cover doubling 1979 2016. There was no increase nonnative minimal evidence homogenization. High‐elevation did not display greater than low‐elevation communities. Moreover, factored little shifts. While distributional were unrelated affinity disturbance, persistent (persisting on >80% sites) long‐lived shrubs associated with disturbance. Overall, seemingly paradoxically, drying abundance. Comparing 1970s 2007–2016, precipitation study area declined 16% from 17 14 cm/yr average daily minimum temperature rose 13% (1.2°C). The current climate fewer freezes, together reduced grazing, could among optimal desert perennials past century, although potential response lags continuing uncertain. This few deserts, upward shift 6 m/decade our within range reported temperate biomes. However, 41% moving downslope unusually high. We propose dynamics follow core‐transient model where site's either highly or transient approximately equal proportions.