Primary production in grasslands and coniferous forests with climate change: an overview

Most estimates of primary production have been made by extrapolation from measured standing crops. For grasslands, this approach is seriously in error. Detailed information is available on the responses of individual plant processes to individual climatic variables at the leaf, plant, and stand level, giving potential for a more mechanistic approach in modelling. This approach is limited by lack of information on multivariate interactions and on some key physiological processes, and by uncertainties in scaling up to populations and communities. Despite this, some important insights to possible community responses, particularly those of C₃ and C₄ types, may be gained. Knowledge of the responses of different physiological processes underlying production to individual aspects of climate change is considered, and its implications for higher levels of organization are discussed. There is insufficient information to predict accurately the response of primary production to climate change. Of particular promise is the approach of predicting production from light interception and conversion efficiency. -from Authors