Abstract

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 conclusionOur 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.

Keywords

Boreal biome; climate warming; forest succession; FunDivEUROPE; growth; Mediterranean biome; mortality; plant functional traits; recruitment; temperate biome

Published in

Global Ecology and Biogeography
2017, Volume: 26, number: 2, pages: 128-141

SLU Authors

• Dahlgren, Jonas

  • Department of Forest Resource Management, Swedish University of Agricultural Sciences
    

Associated SLU-program

Forest


Sustainable Development Goals

SDG15 Protect, restore and promote sustainable use of terrestrial ecosystems, sustainably manage forests, combat desertification, and halt and reverse land degradation and halt biodiversity loss


UKÄ Subject classification

Forest Science


Publication identifier

DOI: https://doi.org/10.1111/geb.12515

Permanent link to this page (URI)

https://res.slu.se/id/publ/78259