The position of the tree line is a key indicator of climate change and land-use impacts in high-latitude and mountain ecosystems. In northern Sweden (Torne Lappmark), detailed botanical surveys conducted in the early 20th century provide a unique baseline for assessing long-term changes in tree-line position.
A comprehensive study published in 1913 by Thore Fries (Botanische Untersuchungen im nördlichsten Schweden) includes detailed maps and field measurements of the alpine and subalpine tree line. These historical data offer a rare opportunity to quantify how tree lines have shifted over more than a century in response to climate warming and changes in reindeer grazing regimes.
Project description
In this project, you will digitise and georeference historical tree-line maps from the early 1900s and compare them with modern spatial data. The main goal is to quantify long- term tree-line shifts and assess the relative roles of climate change and land use, with a particular focus on altered reindeer grazing pressure.
The project is designed primarily for Master’s students and builds on spatial analyses of historical and contemporary data. Depending on scope, it may focus on a single region
or multiple subregions and can include descriptive analyses as well as hypothesis-driven statistical modelling.
Methods and tasks
- digitisation and georeferencing of historical vegetation maps
- extraction of tree-line positions from historical and modern spatial data
- analysis of long-term tree-line shifts
- integration of climate data and land-use information (reindeer grazing)
- spatial and statistical analysis in R
- interpretation of results in an ecological and biogeographical context
What you will learn
- principles of climate change ecology and long-term vegetation dynamics
- working with historical maps and spatial ecological data
- applied GIS-based analysis and spatial data handling
- statistical analysis and visualisation in R
- scientific writing and interpretation of climate- and land-use-driven changes
This project is primarily intended for MSc students in landscape ecology, geography, environmental sciences, or related programmes. Basic GIS skills (e.g. handling spatial data, map visualisation) are required; experience with R is beneficial but not mandatory.
Key references for further reading
Van Bogaert, R., Haneca, K., Hoogesteger, J., Jonasson, C., De Dapper, M. and Callaghan, T.V. (2011), A century of tree line changes in sub-Arctic Sweden shows local and regional variability and only a minor influence of 20th century climate warming. Journal of Biogeography, 38: 907-921, doi.org/10.1111/j.1365-2699.2010.02453.x
Harsch, M.A., Hulme, P.E., McGlone, M.S. and Duncan, R.P. (2009), Are treelines advancing? A global meta-analysis of treeline response to climate warming. Ecology Letters, 12: 1040-1049, doi.org/10.1111/j.1461-0248.2009.01355.x
Moen, J., Aune, K., Edenius, L., & Angerbjörn, A. (2004). Potential Effects of Climate Change on Treeline Position in the Swedish Mountains. Ecology and Society, 9(1), jstor.org/stable/26267652
Contact
- Prof. Dr. Sergey Rosbakh | Geobotany | Vegetation ecology, biodiversity and ecosystem dynamics group
