Increased litterfall productivity in coastal dry forests of Argentina invaded by Ligustrum lucidum

Endangered coastal dry native forests in Argentina are currently threatened by glossy privet (Ligustrum lucidum) invasion. The main objective of this study was to estimate and compare litterfall productivity in these dry forests with different degrees of L. lucidum invasion; and to analyse the relationship between invasion and soil nutrients. Leaf litter productivity in invaded forests was three times higher and fruit litter productivity was seven times higher than in preserved and partially-preserved forests. Although total litterfall dynamics showed a similar seasonal pattern across all forests, leaf and fruit litter productivity were different among forests, and native species’ contribution to leaf litter decreased from 81,9 % in preserved forests to 1,9 % in invaded forests. Soil litter layer depth increased almost four times in glossy privet invaded forests. Despite these changes, no differences were detected in soil nutrient and carbon contents among forests, except for a lower organic phosphorus content in invaded forests. Although partially-preserved forests remain functionally similar to preserved forests in terms of litterfall dynamics, their ongoing invasion by L. lucidum indicates a potential risk of structural shifts, suggesting that very rapid management interventions are required.