Legacy effects of long-term autumn leaf litter removal slow decomposition rates and reduce soil carbon in suburban yards

Seasonal senesced leaf litter removal eliminates considerable organic material from suburban soils annually. We test if this disturbance alters decomposition and carbon cycles and depletes soils of organic matter over time, creating persistent legacy effects.We used a factorial experimental design to implement 1-2 years of current leaf litter manipulations (remove or retain fallen leaves) within historically raked and unraked yard areas in suburban Maryland yards. We then compared total organic soil carbon and decomposition using a standardized substrate decomposition methodology (Tea Bag Index) across treatment plots.Long-term litter removal in suburban yards reduced decomposition rates by 17% and total soil organic carbon concentration by up to 24% compared to areas where leaf litter was retained in situ. In contrast, short-term management changes (1-2 years) did not significantly impact decomposition rates or total organic soil carbon concentrations.Our findings suggest that long-term suburban litter raking creates legacy effects that alter decomposition and carbon storage process trajectories that are not easily reversed. This is important in understanding urban ecosystem function and sustainable management.