Space for time - How do peatland vegetation patterns develop through time?

By Timon Weitkamp (the Netherlands)

Abstract
Boreal peatlands grow slow, thus tracking the spatial vegetation pattern development within a peatland requires a long time. In an area where new land emerges due to glacial rebound, such as northern Sweden, new peatlands can grow on the new soils. Pattern development can be analysed through time by using a chronosequence, without taking the required long time. This research used high-resolution aerial imagery to classify peatlands in five classes, after which hummock patches were used to analyse pattern development. The age of peatlands was determined by calculating when the peatland was located on the shoreline, based on the elevation and isostatic rebound. Overall, this research found that hummock patches start small in young peatlands, and grow together to form long, wide patches as the peatland grows older (at least 2000 years), however this does not occur in all peatlands. The minor and major range, and the radius of gyration had the highest correlations with age (r2 = 0.263, 0.214 and 0.128, respectively), whilst the total catchment area above a peatland (r2 = 0.397) was determined to have the most influence on pattern development. Factors that contributed to the low R-squared are the location and the number of sampling points. In conclusion, it is possible to analyse spatial vegetation pattern development by using high-resolution aerial imagery and pattern metrics.