Ecological significance of plant biomass turnover

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The distribution of plant species is largely determined by their ability to cope with the environmental conditions in different habitats, conditions such as the availability of nutrients, water and light. A plant's ability to acquire these resources is in this respect an important and well-studied trait. Equally important, but less studied, is the plant's ability  to avoid losses of the once acquired resources, i.e., its biomass turnover rate. Resource acquisition is closely related to growth rate; resource loss to life span of leaves and roots. There is generally a reverse relationship between growth rate and organ life span: plants which grow fast usually produce short-lived leaves and roots. The aim of this program is to investigate factors underlying the tradeoff between growth and lifespan, and the consequences for species' performance in different environments. Environmental factors included in the investigations are productivity, rate of disturbance and growing season length. The program consists of garden and field experiments. Short-term investigations of plant structure will be combined with long-term experiments about interactions between the species. An important aspect of the program is that roots will be included in the investigations. In herbaceous communities roots often make over 50% of the biomass production, but are frequently neglected in studies about plant growth strategies. This program addresses basic questions about ecological and evolutionary mechanisms, but it is also potentially important for understanding the consequences of changes in land use and climate. Biomass turnover characteristics of vegetation strongly influence nutrient and carbon cycling in ecosystems. Insight, for example, in the relationship between growing season length and biomass turnover rate is essential for our understanding of carbon sequestration in soils in a changing climate, an important aspect with respect to measures to fulfill the Kyoto agreement.