Long‐term changes in flowering synchrony reflect climatic changes across an elevational gradient

Synchrony defines an organism's overlap with potential resources and mates, essential for survival reproduction. Flowering synchrony influences gene flow within species patterns of interaction among plants other trophic levels, including pollinators. Climate‐change driven shifts in plant phenology may disrupt plant–plant plant–pollinator interactions, resulting reshuffling communities altered ecosystem processes. We present a unique long‐term metacommunity‐wide study relating changes flowering along elevational gradient to local climatic conditions. apply circular statistical method that estimates between entire distributions, overcoming limitations biases single indicators such as first last dates. analyzed more than 300 000 217 five across 1267 m over four decades (1984–2019) the southwestern USA. show co‐flowering significantly decreased all communities, maximum 28.1% lost at lowest elevations. Decreased was negatively correlated increasing temperatures recorded gradient. Reduced precipitation had locally‐dependent effects and, combination warmer temperatures, accelerated decrease synchrony, especially occurring multiple increased most community pairs, increase 30.5%, rates recent years. The exception, likely associated differences topography, 5.6% two highest‐elevation communities. Overall, elevations indicates homogenization These results significant reshaping response changing climate. Because many ecological processes, fundamental have far‐reaching negative on stability.