Higher survival drives the success of nitrogen-fixing trees through succession in Costa Rican rainforests

Authored by Duncan N L Menge, Robin L Chazdon

Date Published: 2016

DOI: 10.1111/nph.13734

Sponsors: United States National Science Foundation (NSF)

Platforms: R

Model Documentation: Other Narrative Mathematical description

Model Code URLs: Model code not found

Abstract

Trees capable of symbiotic nitrogen (N) fixation ('N fixers') are abundant in many tropical forests. In temperate forests, it is well known that N fixers specialize in early-successional niches, but in tropical forests, successional trends of N-fixing species are poorly understood. We used a long-term census study (1997-2013) of regenerating lowland wet tropical forests in Costa Rica to document successional patterns of N fixers vs non-fixers, and used an individual-based model to determine the demographic drivers of these trends. N fixers increased in relative basal area during succession. In the youngest forests, N fixers grew 2.5 times faster, recruited at a similar rate and were 15 times less likely to die as non-fixers. As succession proceeded, the growth and survival disparities decreased, whereas N fixer recruitment decreased relative to non-fixers. According to our individual-based model, high survival was the dominant driver of the increase in basal area of N fixers. Our data suggest that N fixers are successful throughout secondary succession in tropical rainforests of north-east Costa Rica, and that attempts to understand this success should focus on tree survival.

Tags

Dynamics Trade-off Fixation Secondary succession Leaf economics spectrum Tropical wet forest Phosphorus limitation Neotropical forests Soil-phosphorus Worlds forests