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Research
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Research Laboratory for
Functional Plant Ecology
Dr. Peter Ryser
Research focus
Ecological significance of interspecific variation in plant biomass turnover and underlying traits
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What is biomass turnover ? |
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Plants grow and they die. Their leaves and roots have a certain life-span, which varies depending on the species and the environmental conditions under which the plant grows. Research has traditionally focused on growth, but recent experiments have shown that the life-span of plant tissue, i.e., how long a given leaf or root lives, is at least equally important in determining the long-term performance of a plant in a given environment.
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Which traits underlie variation in biomass turnover rate ? |
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Both the relative growth rate and the life-spans of leaves and roots are associated with tissue structure of a particular species. A plant can grow fast if it has a low investment in dry matter per unit volume of tissue, i.e., a given amount of dry matter allows the building of a large leaf area and a long root system to acquire above-ground and below-ground resource. On the other hand, low-density tissue has a short lifespan, leading to a higher loss rate of acquired resources. Tissue density thus underlies the trade-off between resource acquisition capacity and resource conservation ability. |
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Why do plant species differ
in their biomass turnover rate ? |
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Plants of productive habitats are usually good at acquiring resources while plants of un-productive sites are better able to conserve acquired resources. However, productive sites are frequently disturbed, e.g., by grazing, and this disturbance seems to be a more important factor favouring the fast-growing species on such sites rather than the productivity itself. Absence of disturbance favours species with long-lived organs. On productive sites, a short growing season favours fast-growing species .
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Do the species-specific traits have consequences for the carbon and nutrient cycling in ecosystems ? |
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Dominance of vegetation by fast-growing species leads to high soil nitrogen mineralisation rates due to easily-decomposable litter. Nutrient exports from the ecosystem are regulated by the phenological pattern in leaf production and leaf mortality of the dominant species.
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