Herbivores and a warming climate affect tundra plant community nutrient levels

Top image: Matteo Petit Bon on fieldwork in Adventdalen. Photo: Anton Hochmuth.

How do herbivores and a warming climate affect tundra plant community nutrient levels? PhD candidate Matteo Petit Bon investigated this and found that herbivores and climate warming cause immediate changes in tundra plant-community nutrient levels, and that these changes are happening at a much shorter timescale than previously revealed. Bon will defend his PhD thesis digitally on 22 September 2020.

21 September 2020
Press release from the University Centre in Svalbard (UNIS) and UiT – The Arctic University of Norway

In the long-term, herbivores and climate warming have been shown to alter nutrient levels in tundra plant communities by changing the functional composition of the vegetation. Matteo Petit Bon investigated the extent to which they affect tundra plant-community nutrient levels in the short-term by directly modifying the chemistry of plants.

Bon first developed a time- and cost-effective method to account for the high variability in nutrient-related plant traits among plant individuals, and further scale up to the plant-community level. Then, he applied such methodology to investigate short-term (one/two-year) plant-community nutrient-level responses to herbivores in sub-Arctic/alpine tundra-grasslands (Finnmark) and to herbivory and warming across different habitats in a high-Arctic ecosystem (Svalbard).

Herbivory and warming were key, short-term modifiers of tundra plant-community nutrient levels, thus affecting plant-community nutrient dynamics, herbivore forage quality, the amount of nutrients available to herbivores in summer and the biogeochemistry of the ecosystem.

This thesis provides clear evidence that herbivores and climate warming cause immediate changes in tundra plant-community nutrient levels, and that these changes are happening at a much shorter timescale than previously revealed. Considerable short-term changes in plant-community nutrient levels, as those detected in this work, are likely to have strong implications for the immediate functioning of tundra ecosystems and the trophic interactions established therein.

Dissertation
Matteo Petit Bon will defend his PhD thesis entitled “Short-term tundra plant-community nutrient responses to herbivory and warming: New insights from Near infrared-reflectance spectroscopy methodology” on 22 September at 14:45. He will give a trial lecture entitled «Effects of extreme climatic events (both summer and winter extremes) on tundra ecosystem functioning» at 13:30 the same day.

The evaluation committee consist of Professor Rien Aerts, Amsterdam University, the Netherlands (1. opponent), Professor Laura Gough, Towson University, USA (2. opponent) and Researcher Ole Petter Laksforsmo Vindstad, AMB (internal member and leader of the committee). The disputation will be led by Vice dean Michaela Aschan, Faculty of Biosciences, Fisheries and Economics, UiT.

The thesis is available here: https://hdl.handle.net/10037/19213