Doctoral dissertation: Soil moisture has a strong influence on Arctic vegetation

Physical geographer Julia Kemppinen found in her doctoral thesis that the interaction between soil moisture and plants is strong in the Arctic.
Tunturimaisema on sulavesipurojen halkomaa. Maaperän ja maanpintojen muodot säätelevät minne vesi kertyy, kuten tasaisille, turpeisille niityille. Kuva: Julia Kemppinen.

In summer, meltwater streams are abundant in tundra mountain landscapes. Mainly mosses and some vascular plants, such as Saxifraga aizoides (in front), thrive in high soil moisture. Photo: Julia Kemppinen.

Moisture conditions affect different species groups, such as vascular plants, mosses and lichens, both at the individual and community levels. This highlights the importance of soil moisture in the vulnerable Arctic ecosystem.

Soil moisture and its spatial distribution are controlled by soil and topographic factors, but also woody plants influence soil moisture. Shrubs and dwarf shrubs are expanding in the tundra, which will affect the climate through the cycles of water, energy and carbon.

– Water is vital for life, also for vegetation. Water affects the growth, survival and spatial distribution of plants, which is why I am interested in moisture conditions, says Julia Kemppinen.

Kemppinen collected data for her thesis across the Arctic. Field work took her from the Fennoscandian mountains to western Greenland and Svalbard.

In her thesis, Kemppinen modelled the spatial and temporal variation of soil moisture, analysed the impact of soil moisture on tundra vegetation and also used dwarf shrubs to model soil moisture.

The conclusion of the thesis is that water really is an important driver of tundra vegetation, as it affects plants in multifaceted ways. Kemppinen will continue her soil moisture investigations in her postdoctoral research: she wants to know what will happen to the northern environments if water conditions will change in a warmer future.

Kemppinen carried out her doctoral dissertation at the BioGeoClimate Modelling Lab led by professor Miska Luoto at the Department of Geosciences and Geography.

Julia Kemppinen, FM will defend the doctoral dissertation entitled "Soil moisture and its importance for tundra plants" in the Faculty of Science, University of Helsinki, on 14 May 2020 at 12:15.

Professori Signe Normand, Aarhus University, will serve as the opponent, and Professor Miska Luoto as the custos. The dissertation will be published in the series Department of Geosciences and Geography.

The dissertation is also available in electronic form through the E-thesis service: Soil moisture and its importance for tundra plants

Contact information:

Julia Kemppinen, BioGeoClimate Modelling Lab, University of Helsinki
Twitter: @juliakemppinen

Tundra plants and geographer’s field equipment at the slopes of Mount Saana.