New Approaches to Functional Diversity

FIGURE 8 A pan-European field experimenl (a) Overall log-linear reduction of above ground biomass with the simulated loss of plant species richness, (b) Linear reduction with the loss of functional group richness within species richness levels, (c) Biomass patterns at each site (displayed with species richness on a log. scale for comparison with panel (a)) (Hector et al., 1999). 

FIGURE 10 The relationships between evapotranspiration and net primary production as they emerge from the Century model, applied globally. The near-linear realtionship between evaporation and NPP, very similar to those observed In semi-arid lands, is an emergent property. The differences in slope between biomes are largely due to differences in the C N ratio of different plant functional types. Indicating that ecosystem composition has direct effects on biogeochemistry (Scholes et al., 1999). 

Single species appear to determine the NPP processes in the ecosystem in a more than proportional manner. It will be a major task of future research to identify these species and their characteristics and develop modeling approaches. 

Current identification of biomes is not based on a functional analysis, and while some major biomes function similarly in carbon uptake (e.g., European conifer and deciduous forest), within-biome or-species effects can be extremely large. New ways of organizing ecological variability are needed. 

The quantification of the mean residence time of vegetation and soil compartments and an understanding of the parameters that control this time-scale is necessary for process-based predictions of carbon storage. 

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