The Impact of Lesser Snow Goose Herbivory on Above and Belowground Nutrient Dynamics in Two Sub-Arctic Ecosystems

• Main Author: Horrigan, Emma J.
• Other Authors: Jefferies, Robert L., Ecology and Evolutionary Biology
• Format: Thesis
• Language: English
• Subjects: lesser snow geese; microbes; rhizosphere; nitrogen; 0309; Arctic; Churchill
• Online Access: http://hdl.handle.net/1807/24580

In order to determine the impact of lesser snow goose (Chen caerulescens caerulescens) herbivory on above and belowground nutrient dynamics, a grazing and nutrient addition experiment was conducted in two habitat types utilized by snow geese near Churchill, Manitoba. Forage plant nutrition, soil microbial biomass, and inorganic and organic soil nutrients were measured in relation to the timing of grazing, over two consecutive summers. Soil was collected from the rhizosphere to determine the influence of foliar herbivory on root-microbe interactions. Primary productivity in both habitats is co-limited by the availability of both nitrogen (N) and phosphorus (P). Aboveground defoliation either caused a reduction or no change in soil microbial biomass nutrients (carbon (C), N, or P). Defoliated shoots had higher N concentrations and did not show compensatory growth within the season. Root biomass was somewhat reduced with grazing, but higher whole plant N content suggests that grazing does not compromise N-uptake. MAST