Ecosystem parameter mapping in Swiss National Park based on a continuous fields approach

Adequate assessment and management of landscape patterns and processes need proper representation and quantification of gradients of ecosystem biochemical and structural properties. Discrete land cover mapping approaches represent landscapes as classified entities with “hard” boundaries. On the other hand, continuous field representations of land cover or ecosystem parameters offer the potential to overcome the limitations of classified entities that can often not reproduce the full range and variability of land surface properties. This paper presents a concept to generate continuous fields (CF) maps of ecosystem parameters in an alpine environment. The concept is exemplarily presented on a high mountain ecosystem's total (above ground) water content and is performed in the upper Trupchun valley (Val Trupchun) in the Swiss National Park (SNP). It is applicable to further parameters. Airborne Prism EXperiment (APEX) imaging spectrometer (IS) data collected over the SNP in June 2010 and 2011 are used for CF mapping of water content. Abundance maps of predominant land cover classes are derived from linear spectral mixture analysis (SMA). They are then combined with individual thematic water content information of the respective land cover originating from either spectral indices or a physically based approach. The resulting product depicts a spatially continuous representation of total water content. The availability of APEX IS data from two consecutive seasons allows studying differences in ecosystem water content over time. CF maps can be generated for a wide range of ecosystem parameters. If multi-temporally available, such products can be useful for explaining ecological patterns such as animal grazing patterns in SNP.