Grant: Discovery Grants Program - Individual

The distribution of plant species is largely determined by their ability to cope with the environmental conditions in different habitats, 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 turnover rate. Resource acquisition is closely related to growth rate, resource loss with life spans of leaves and roots. There is generally a reverse relationship between growth rate and organ life span: fast-growing plants usually produce short-lived leaves and roots. This projects concerns basic questions about ecological and evolutionary mechanisms with respect to turnover, but it is also potentially important for understanding the consequences of changes in land use and climate. One aim of this project is to consolidate our current understanding about the consequences of a given turnover rate for the species' performance in different environments, and put this in a broad theoretical context. There is detailed knowledge about the importance of many traits in specific situations, but the adaptive advantage of certain turnover characteristics at a general level is still often based on assumptions, not mechanistic understanding. The models to be developed in this project will help to fill this gap. Another main aim is to increase our knowledge about below-ground processes, which still is limited. This is the case especially in natural ecosystems such as wetlands, which cover large areas in Canada's North. Recent evidence shows that life spans of fine roots in such ecosystems, which often is assumed to be very short, may be much longer. Belowground prodution often exceeds the above-ground one, and fine root turnover is considered as an important part of total carbon cycle in these environments. To understand it fully we need to know more about root mortality pattern and factors controlling it.