SP01e Aboveground primary productivity in forest ecosystems as a function of species diversity and composition (sp01e production)

Forests are the most productive vegetation type on Earth and responsible for more than 50 % of global net primary productivity (NPP). Accordingly, forest-mediated carbon (C) fluxes and C storage interact with the global climate. An important question is, therefore, both from a practical and basic science perspective, how biodiversity affects NPP and biomass of forests. Most field studies manipulating plant species diversity so far have been conducted in herbaceous ecosystems and have revealed a positive relationship between species richness and productivity of plants. However, tree communities differ substantially from herbaceous ones with respect to scale, architecture, and longevity of the component individuals, and a number of reasons suggest that not only biodiversity effects on NPP but also the underlying driving mechanisms may differ between the two different vegetation types. In the subproject 1 Europe (P1e), we will continue and extend our assessment of biodiversity effects on NPP. Effects will be analyzed in terms of species richness, the presence/absence of particular species, the composition of plant communities and the diversity of the shrub un-derstory. Larger-scale spatial variation will be accounted for by adopting the Ecoscapes Concept. Standing biomass assessments will distinguish woody and leaf biomass, and we will estimate the turnover of woody and leaf biomass, since these can dominate NPP, depending on conditions. We closely collaborate with the subproject of our Chinese partner, Keping Ma, who focuses on belowground productivity, to be able to integrate these measurements to the ecosystem level. In collaboration with the other subprojects, we further provide data and contribute to the development of allometric relations for the respective species, the estimation of C and nutrient stocks, as well as estimates of leaf damage.


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