Building a Framework to Differentiate between Natural and Drained Peatlands in Europe by comparing Molecular and Remote Sensing Data

Peatlands are unique ecosystems with high biodiversity and environmental services such as water filtration and retention as well as carbon storage. Interestingly, however, in contrast to other soils and ecosystems, less is known about the extent and health (natural/rewetted versus drained/ degraded) of European peatlands¹. With past human-induced drainage and degradation and recent or emerging restoration, there is an even greater need to monitor the extent and health of European peatlands¹. Here we present results of a novel approach to (1) distinguish between unforested peatlands and surrounding areas (forest and grassland), and (2) separate drained/degraded from natural/rewetted peatlands, based on 12 European peatlands in three Köppen-Geiger climate classes². We compare remote sensing data (Sentinel 2, PlanetScope optical bands) with the molecular composition of surface soils to differentiate between natural and drained peatlands. The peatland vegetation and surrounding areas are seperated based on red and near infrared (NIR) bands³. Furthermore, the natural and drained peatlands are distinguished by their Normalised Difference Vegetation Index (NDVI), Enhanced Vegetation Index Red (EVI), Green Normalised Vegetation Index (gNDVI) and Greenness Index (GI); known indicators of vegetation composition and health^3,4. Simultaneously, two types of soil data were measured as indicators of soil health, i) peat stoichiometry (e.g., carbon to nitrogen ratio, degree of carbon oxidation), and ii) peat molecular composition using pyrolysis gas chromatography with integrated mass spectroscopy (PYGCMS), a fast and valid method to study a wide range of molecular compounds⁵. In particular, we analysed the relative abundance of molecules indicative of different vegetation classes and their transformation products, as well as the relative contribution of microbial input. The results showed that the red and NIR bands were useful to distinguish between grasslands and peatlands as the reflectance of grasslands is significantly high compared to peatlands. In addition, we were able to distinguish between drained and natural peatlands by the optical indices used. The molecular composition and remote sensing indicators of the sites clearly correlated and natural and drained sites could be distinguished. Therefore, remote sensing data might serve as a fast and valid method to obtain information on the extent and health status of European peatlands under different climatic conditions.

 

REFERENCES

¹Andersen, R. et al, https://doi.org/10.1111/rec.12415.

²Kottek, M. et al, https://doi.org/10.1127/0941-2948/2006/0130.

³Burdun, I. et al., https://doi.org/10.1016/j.rse.2023.113736.

⁴Räsänen, A. et al., https://doi.org/10.1016/j.jag.2022.102866.

⁵Klein, K. et al., https://doi.org/10.1016/bs.agron.2020.09.002.