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Secondary tropical forests play an increasingly important role in climate change mitigation, biodiversity conservation, and timber provision. We are beginning to understand how community-level metrics, such as biomass, species richness, or functional composition of the tree community recover. However, successional changes in community composition arise from differences in demographic rates of the multiple tree species that comprise local communities. Yet, our mechanistic understanding of and ability to forecast shifts in dominance of different demographic strategies across succession remains limited. We used demographic rates of 787 tree species across two wet and two dry Neotropical forests to identify generalities in demographic trade-offs and patterns of forest succession. We found two consistent trade-offs in wet and dry forests. The first one is the growth-survival trade-off distinguishing species with fast growth and low survival (fast species) from species with slow growth and high survival (slow species). The second one is a trade-off between fast growth and high survival – and hence tall adult stature (long-lived pioneers) – versus high recruitment rates per unit of basal area in the old-growth forest (short-lived breeders). This consistent and data-driven definition of demographic strategies enabled us to explore general patterns in tropical forest succession across the four forests. As expected, early succession was dominated by fast species in three of the four forests. Slow species increased in basal area over succession, but remained at low levels in three of the four forests. In contrast to expectations, long-lived pioneer species dominated not only at intermediate successional stages but also in the old-growth stage in all forests. This calls for a revision of our current definition of the ‘old-growth’ stage. Instead of relying on the disappearance of long-lived pioneer species from the forest it should incorporate their persistence and (co)dominance.

Keywords:

conceptual model of succession, demographic strategies, life-history strategies, species classification

Nadja Rüger, Markus Schorn, Stephan Kambach, Robin Chazdon, Caroline Farrior, Jorge Meave, Rodrigo Muñoz, Michiel van Breugel, Lucy Amissah, Frans Bongers, Bruno Hérault, Catarina Jakovac, Natalia Norden, Lourens Poorter, Masha van der Sande, Christian Wirth, Diego Delgado, Daisy Dent, Saara DeWalt, Juan Dupuy, Bryan Finegan, Jefferson Hall, Stephen Hubbell, Omar Lopez

Presentation within symposium:

S-25 Secondary forest succession; theory, synthesis and application

Does one model fit all? Shifts in tree demographic strategies across succession in wet and dry Neotropical forests

-Review-