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Impacts of air pollution and climate change on forest ecosystems - Multiple stressors and ecosystem services
Citation:
Grulke, N. E. AND C. P. ANDERSEN. Impacts of air pollution and climate change on forest ecosystems - Multiple stressors and ecosystem services. Presented at IUFRO Conference: Adaptation of Forest Ecosystems to Air Pollution and Climate Change, Antalya, TURKEY, March 22 - 26, 2010.
Impact/Purpose:
The nature of scientific investigation involving hypothesis testing dictates the need to conduct controlled experiments, limiting the number of independent variables in order to identify cause and effect relationships.
Description:
The nature of scientific investigation involving hypothesis testing dictates the need to conduct controlled experiments, limiting the number of independent variables in order to identify cause and effect relationships. Single or two-factor studies are useful to identify potential factors influencing growth of relatively small or young trees under controlled conditions, but provide insufficient information about how mature trees respond within ecosystems, or how forest ecosystems respond to multiple factors varying in space and time. This new section of the working party is designed to highlight the effect of multiple stressors on forest species within ecosystems or forest ecosystems themselves. One approach to conducting this type of research is to utilize gradients in growth stressors (drought, strong oxidants, excess nitrogen deposition) or enhancers (elevated CO2, low nitrogen deposition) varying across landscapes, over moderate to long periods of time. In these studies, which are often quite large, it is difficult to tease out the effect of a single factor within the context of the other stressors, never-the-less, it is an important approach to validate model outputs. Another focus of this new section is to shift the endpoint of interest from individuals or forest stands to ecosystem functions or ‘services’. Ecosystem services are society’s valuation of the physical and biological functions of ecosystems. Examples of ecosystem services include water quality and quantity, clean air, greenhouse gas mitigation, and habitat protection. Understanding and quantifying ecosystem services requires integrative, interdisciplinary research at several levels of biological organization. Although focusing on ecosystem functions or endpoints may not initially reveal mechanistic information about individual or multiple stressors, it helps focus our attention on ‘science that matters,’ and can provide a basis for hypothesis testing. The goal of this session is to help bring awareness to and to promote investigations at this higher level of physical and biological complexity. An example of one ecosystem service, greenhouse gas regulation, will be discussed to illustrate the benefits and challenges associated with studying forested ecosystems from an ecosystem services framework.