Global forest gaps reduce litterfall but increase litter carbon and phosphorus release

Ongoing global climate change and conventional forestry have led to a dramatic increase in new forest gaps, predicted to strongly impact litter turnover and nutrient cycling. Here we synthesized 8739 paired observations to quantify the impacts of naturally occurring and artificially created gaps on litterfall, litter decomposition, and the release of carbon and nutrients. Globally, forest gaps decreased annual litterfall by 29.5% and litter remaining carbon and phosphorus by 5.6%, while litter decomposition increased in the 0–20% mass loss interval. Climate and litter quality showed a major contribution to forest gap effects on litter decomposition, with gap characteristics further influencing the release of carbon and nutrients during decomposition. Our results uncovered the potential impact of escalating forest gaps on reducing litter turnover and carbon sequestration, providing support for the inclusion of gaps into global litter dynamic models to improve predictions of ecosystem material cycling responses to ongoing climate change. The increased abundance of forest gaps, influenced by climate and litter quality, could reduce annual litterfall by 29.5% and carbon and phosphorus remaining by 5.6%, while litter decomposition could increase in 0–20% mass loss intervals, according to a global meta-analysis of the 8739 paired observations.