Recovery of tree-related microhabitats in a tropical rainforest after agricultural abandonment

The restoration of degraded tropical forests is a global priority to halt terrestrial biodiversity loss. However, the complexity and hyper diversity of tropical forests challenge the quantification of their recovery status. Unlike temperate forests, where tree-related microhabitats (TreMs) have been established as a surrogate for habitat diversity, TreMs have received little attention in the tropics. Here, we investigated the recovery of TreM profiles along a chronosequence of forest recovery ranging from cacao plantations and pastures to abandoned agricultural land (2 to 38 years), and old-growth forests in the Ecuadorian lowland Chocó forest. Our analysis accounted for sample incompleteness and different abundance weightings using Hill numbers. Based on 57 TreM types, we identified an overall increase in diversity over time. Pasture regenerations exhibited a steeper and more continuous shift of TreM diversity and composition along the recovery gradient, likely due to more remnant trees that retained TreMs, in contrast to cacao regenerations. Diversity, community composition and numerous typical TreM types show that old-growth forests maintain distinct TreM profiles. In addition, Ferns and hemiepiphytes had the highest number of positive co-occurrences with other TreMs, while stiltroots excluded both buttress roots and trunk base rot holes. Using multiple regression in distance matrices we identified tree species richness and light availability as the main drivers of TreM composition. Our TreM results call for a strategy of protecting old-growth forests with their unique and diverse TreM profiles and of favouring agricultural sites with remnant trees for restoration due to faster achievements in habitat diversity. • Increase of TreM diversity with increasing time since abandonment • Former pastures exhibit shift of TreM diversity with forest age, due to remnant trees. • Old-growth forests maintain distinct TreM profiles. • Tree-species richness and light availability are main drivers of TreM composition.