Code and data for The unexpected influence of conspecific density dependence

When plants die, neighbours escape competition. Living conspecifics could disproportionately benefit because they are freed from negative intraspecific processes; however, if negative effects of past conspecific neighbours persist, other species might be advantaged, and diversity maintained through legacy effects. We examined legacy effects in a mapped forest by modelling the survival of 37,212 trees of 23 species using four neighbourhood properties: living conspecific, living heterospecific, legacy conspecific (dead conspecifics), and legacy heterospecific densities. Legacy conspecific effects proved nearly four times stronger than living conspecific effects; changes in annual survival associated with legacy conspecific density were 1.5% greater than living conspecific effects. Over 90% of species were negatively impacted by legacy conspecific density compared to 47% by living conspecific density. Our results emphasize that legacies of trees alter community dynamics, revealing a significant oversight in prior research, which may have underestimated the strength of density dependence by not considering legacy effects.