Journal Article

Functional diversity underlies demographic responses to environmental variation in European forests

4100100411, Lehtonen, Aleksi, Forest Research Institute of Baden-Württemberg, Germany, Instituto de Recursos Naturales y Agrobiologia de Sevilla, Spain, Swedish University of Agricultural Sciences, Umeå, Luke / Luonnonvarat ja biotuotanto / Ympäristövaikutukset / Ilmastonmuutoksen hillintä ja sopeutuminen, Wirth, Christian, Kattge, Jens, Max Planck Institute of Biogeochemistry, Germany, Ruiz-Benito, Paloma, Zavala, Miguel A, Universidad de Alcala, Spain, Kändler, Gerald, University of Leipzig, Germany, University of Stirling, UK, Ratcliffe, Sophia, Dahlgren, Jonas, Jump, Alistair S, Madrigal-Gonzalez, Jaime, Gomez-Aparicio, Lorena, German Centre for Integrative Biodiversity Research, Leipzig

2017

Overview

Aim: Biodiversity loss and climate-driven ecosystem modification are leading to substantial changes in forest structure and function. However, the effects of diversity on demographic responses to the environment are poorly understood. We tested the diversity hypothesis (measured through functional diversity) and the mass ratio hypothesis (measured through functional identity) in relation to tree growth, tree mortality and sapling abundance. We sought to determine whether functional diversity underlies demographic responses to environmental variation in European forests. Location: Europe (Spain, Germany, Wallonia, Finland and Sweden). Methods: We used data from five European national forest inventories from boreal to Mediterranean biomes (c. 700,000 trees in 54,000 plots and 143 tree species) and the main forest types across Europe (i.e. from needle-leaved evergreen forests to broad-leaved deciduous forests). For each forest type, we applied maximum likelihood techniques to quantify the relative importance of stand structure, climate and diversity (i.e. functional diversity and functional identity) as determinants of growth, mortality and sapling abundance. We also tested whether demographic responses to environmental conditions (including stand density, evapotranspiration and temperature anomalies) varied with functional diversity. Results: Our results suggest that functional diversity has a positive effect on sapling abundance and growth rates in forests across Europe, while no effect was observed on tree mortality. Functional identity has a strong effect on mortality and sapling abundance, with greater mortality rates in forests dominated by needle-leaved individuals and a greater abundance of saplings in forests dominated by broad-leaved individuals. Furthermore, we observed that functional diversity modified the effects of stand density on demographic responses in Mediterranean forests and the influence of evapotranspiration and temperature anomalies in forests widely distributed across Europe. Main conclusion: Our results suggest that functional diversity may play a key role in forest dynamics through complementarity mechanisms, as well as by modulating demographic responses to environmental variation.

• Publisher: Wiley Blackwell,Chichester,gb,John Wiley & Sons Ltd,Wiley Subscription Services, Inc
• Subject: Boreal biome / climate / climate warming / deciduous forests / ecosystems / environmental factors / evapotranspiration / evergreen forests / Finland / forest inventory / Forest Science / forest succession / Forests / functional diversity / FunDivEUROPE / Germany / growth / Hypotheses / Mediterranean biome / mortality / national forests / plant functional traits / recruitment / saplings / Skogsvetenskap / Spain / stand density / stand structure / statistical analysis / Sweden / temperate biome / temperature / tree growth / tree mortality / Trees