Defaunated and invaded insular tropical rainforests will not recover alone: recruitment limitation factors disentangled by hierarchical models of spontaneous and assisted regeneration

Most tropical forests are now severely degraded and their ability to recover is highly dependent on frugivores which ensure seed dispersal for most woody plants. The global collapse of large vertebrates therefore raises major concerns about tropical forest succession, but few field studies have been conducted to disentangle recruitment limitations during disrupted succession.
This study took place on Réunion (Mascarenes) where all large native frugivores have been extinct since human colonisation in 1665 and where multiple invasions threaten native ecosystems. We set up 20 experimental blocks on a lava flow dated back to 1800, in plant-impoverished post-defaunation vegetation bordered by old-growth forests. We assessed fecundity, seed dispersal and seedling recruitment of the complete fleshy-fruited plant community and used Bayesian analyses to disentangle the impact of multiple factors on these key processes. In the same blocks, we sowed four native trees assumed to be disperserless t...