Tropical forests remain increasingly threatened by land-use changes and hazards linked to global changes. Preserving the biological diversity of tropical forests as well as their functioning, basis of the multiple goods and services they provide, from food, and shelter to water and nutrient cycling is on the top priority on the global agenda. Considerable uncertainty though remains about the origin and maintenance of the huge diversity of tropical forests as well as about their response to global changes.
To reveal the ecological rules shaping tropical tree communities and anticipate their response to disturbance, we monitored 75ha of forest plots set up on a gradient of disturbance intensity (from 10 to 60% of the ecosystem biomass removed) over 30 years and made use of a large functional traits database browsing major leaf, stem, and seed traits to draw the taxonomic and functional forest trajectories in post-disturbance times.
Results/Conclusions
Disturbance has clearly favored acquisitive functional strategies, leading to enhanced evenness of disturbed forest communities. Although the disturbance impact persisted for more than 30 years, it slowly shifted towards a cyclic regime suggesting a genuine resilience of the studied forest communities despite the large range of disturbance applied.
The tree recruitment trajectory was shaped by the successive appearance of, first, pre-disturbance saplings benefiting from environmental changes, and second of trees coming from the seed bank. Tree composition of second recruitment phase depended on the balance between pure stochastic mechanisms (recruitment limitation representing the chance by which trees settle after disturbance) and more deterministic mechanisms (environmental filters selecting the species the most fitted to post-disturbance environmental changes), the balance between the two depending on the disturbance intensity.
Eventually, our results gives some clues and opens the discussion about the effect of repeated disturbance on tropical forest communities’ recovery.