Rapid Surveys Reveal Temporal Variation in Flowering Community Phenology in a Great Basin Desert Ecosystem

Understanding temporal variation in flowering phenology is essential for predicting plant community responses to climatic change, especially in arid regions where moisture pulses drive productivity. We examined seasonal and interannual patterns of flowering phenology across 4 years (spring 2021-spring 2024) at the western margin of the Great Basin Desert along the Eastern Sierras ecotone (Reno, Nevada). Community flowering was strongly seasonal: spring supported nearly five times more flowering species than fall, consistent with deep winter-spring moisture recharge. Phenological timing varied across functional groups in spring, with herbaceous annuals and non-native species showing more advanced flowering phenology than woody perennials and native species. In fall, communities showed only marginal phenological differentiation among lifespan groups. Interannual variation appeared to track climate conditions, with earlier flowering in cooler, wetter years and delayed flowering in warmer, drier years. Exploratory mixed-effects models suggested that precipitation received the strongest relative support among candidate predictors, although climate variables overall provided limited explanatory power. Our results demonstrate that rapid surveys can detect phenological shifts and functional group responses, offering an efficient monitoring tool for arid landscapes with bimodal flowering seasons or limited monitoring capacity. Because the Reno-Sparks region is among the fastest-warming areas in the United States and lies at the cusp of the Eastern Sierras ecotone, these baseline data provide a critical foundation for tracking future community-level shifts in flowering plant phenology.