Mechanisms driving plant functional trait variation in a tropical forest |
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Authors: | Florian Hofhansl,Eduardo Chacó n‐ Madrigal,Å ke Brä nnströ m,Ulf Dieckmann,Oskar Franklin |
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Affiliation: | 1. International Institute for Applied Systems Analysis, Laxenburg Austria ; 2. Escuela de Biología, Universidad de Costa Rica, San José Costa Rica ; 3. Department of Mathematics and Mathematical Statistics, Umeå University, Umeå Sweden ; 4. Department of Evolutionary Studies of Biosystems, The Graduate University for Advanced Studies (Sokendai), Hayama Japan |
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Abstract: | Plant functional trait variation in tropical forests results from taxonomic differences in phylogeny and associated genetic differences, as well as, phenotypic plastic responses to the environment. Accounting for the underlying mechanisms driving plant functional trait variation is important for understanding the potential rate of change of ecosystems since trait acclimation via phenotypic plasticity is very fast compared to shifts in community composition and genetic adaptation. We here applied a statistical technique to decompose the relative roles of phenotypic plasticity, genetic adaptation, and phylogenetic constraints. We examined typically obtained plant functional traits, such as wood density, plant height, specific leaf area, leaf area, leaf thickness, leaf dry mass content, leaf nitrogen content, and leaf phosphorus content. We assumed that genetic differences in plant functional traits between species and genotypes increase with environmental heterogeneity and geographic distance, whereas trait variation due to plastic acclimation to the local environment is independent of spatial distance between sampling sites. Results suggest that most of the observed trait variation could not be explained by the measured environmental variables, thus indicating a limited potential to predict individual plant traits from commonly assessed parameters. However, we found a difference in the response of plant functional traits, such that leaf traits varied in response to canopy‐light regime and nutrient availability, whereas wood traits were related to topoedaphic factors and water availability. Our analysis furthermore revealed differences in the functional response of coexisting neotropical tree species, which suggests that endemic species with conservative ecological strategies might be especially prone to competitive exclusion under projected climate change. |
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Keywords: | Biodiversity climate change Costa Rica plant functional traits tropical forest |
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