Long-term monitoring of graminoid primary production and goose grazing impact on plant communities on Bylot Island, Nunavut

Primary production is at the base of all terrestrial food webs and is a key parameter determining the length of food chains, and the abundance of herbivores and carnivores at higher trophic levels. It is therefore an important parameter to measure at field sites where important herbivore populations are present. In terrestrial ecosystem, primary production is measured by sampling the vegetation. We are interested into two aspects of the vegetation. First, standing crop, which can be defined as the amount of live abovebiomass present at a given time (usually at the peak of the growing season). Second, annual net primary production, which is the amount of vegetation biomass that has been produced over the course of a growing season. In annual plants, standing crop and annual net primary production are often very similar but in perennial, the two can differ considerably, as the standing crop can represent the amount of live plant biomass that has accumulated over several years. In all ecosystems, production can occur both above and belowground. However, because belowground is exceedingly difficult and time consuming to measure, we will be concerned only by aboveground production (usually, green biomass).