Responses of plant phenology to nitrogen addition: a meta-analysis

Phenology is one of the most sensitive plant processes in response to global change. Anthropogenic activities have considerably increased nitrogen (N) deposition, which significantly affects plant phenology. Although numerous individual studies have been conducted, a comprehensive understanding of how plant phenology responds to external N inputs remains elusive. We therefore conducted a meta-analysis of 117 species responses to N addition to examine effects on phenology in terrestrial ecosystems, and we assessed variations in their responses in relation to ecosystem types, pollination types, functional groups, and environmental conditions. Our results showed that many aspects of plant phenology changed significantly after N addition, as events occurred later and durations were shorter across all biomes, but varied with biome types. The phenology change in cropland was larger than that in grassland after N addition. The response of phenological stages to N addition was consistent in two...