DOI: 10.5061/dryad.22tq8
title: Data from: Disentangling competitive versus climatic drivers of tropical forest mortality

description: 1. Tropical forest mortality is controlled by biotic and abiotic
 processes, but how these processes interact to determine forest structure
 is not well understood. Using long-term demography data from permanent
 forest plots at the Paracou Tropical Forest Research Station in French
 Guiana, we analyzed the relative influence of competition and climate on
 tree mortality. We found that self-thinning is evident at the stand level,
 and is associated with clumped mortality at smaller scales (&lt; 2 m)
 and regular spacing of living trees at intermediate (2.5-7.5 m) scales. A
 competition index based on spatial clustering of dead trees was used to
 build predictive mortality models, which also accounted for climate
 interactions. 2. The model that most closely fitted observations included
 both the competition index and climatic variables, with climate-only and
 competition-only models performing worse than the full model. There was
 strong evidence for size-specific mortality, with highest mortality for
 small and very large trees, as well as sensitivity of trees to drought,
 especially when temperatures were high, and when soils were water
 saturated. The effect of the competition index was more complex than
 expected a priori: a higher CI index was associated with lower mortality
 odds, which we hypothesize is caused by gap-phase dynamics, but there was
 also evidence for competition-induced mortality at very high index values.
 3. The strong signature of competition as a control over mortality at the
 stand and individual scales confirms that it plays a very important role
 in determining tropical forest structure. The complexity of the
 competition-mortality relationship and its interaction with climate
 indicates that a thorough consideration of the scale of analysis is needed
 when inferring the role of competition in tropical forests, but
 demonstrates that climate-only mortality models can be significantly
 improved by including competition effects, even when ignoring
 species-specific effects. 4. Synthesis Empirical models such as the one
 developed here can help constrain and improve process-based vegetation
 models, serving both as a benchmark and as a means to disentangle
 mortality processes. Tropical ecosystem dynamic models would benefit
 greatly from explicitly considering the role of competition in stand
 development and self-thinning while modeling demography, as well as its
 interaction with climate.
description: Data for self-thinning
 analysisContains data for mean
 aboveground biomass per individual and tree density for each
 plot.selfthinning.csvData for spatial analysisContains geographic coordinates, year, and plot code for each tree, as well as a status code and whether the tree is dead or alive.spatialanalysis.csvData for mortality modelContains data for each individual tree used for mortality modeling: whether the tree is dead/alive, its DBH, the temperature and precipitation in the preceding wet and dry seasons, and the Competition Index using radii of 5 and 10 meters.mortalitymodel.csv