Modelling of a map of the conservation status of the FFH open-air habitat types of the Natura 2000 area Ennstal Alps/Gesäuse National Park Gesäuse

This report documents the procedure for modelling a map of the conservation states of the Offenland FFH habitat types (FFH-LRT) in the Natura 2000 area of the Ennstal Alps/Gesäuse & Gesäuse National Park. The conservation status map available to date (digital only; Report: Zimmermann 2018) only shows the conservation status (ETZ) of forest FFA habitat types (including bushes), but also discusses the approach for all other habitat types. Our project is essentially the GIS technical implementation of the proposed modelling approaches. The demarcation of the FFH habitat types follows the FFH habitat type map (Zimmermann 2017a). As handled in Zimmermann 2018, we adhere to the indicators from Ellmauer 2005 and derive them from an existing data basis. For example, qualitative information on vegetation, such as the degree of shielding or the influence of pasture, can be obtained from the Habitalp aerial image interpretation. Other indicators, such as impairment, were derived from the path network and the climbing routes. Altitude data and calculated altitude levels and slope inclinations are generated from a terrain model (DGM) based on Airborne Laser Scanning (ALS). In contrast to the forest map version, the modelling of the conservation states is implemented in QGIS with the Graphical Modeller. For the calculation, various processing tools are lined up in a graphical model and at the end provide a layer with single-surface conservation states. The approach of using individual indicators to determine a conservation status for each individual area is maintained. The graphical models, with all calculation and combination logics, are comprehensible in digital and editable form. Already in the first version of the conservation status map, the Habitalp aerial image interpretation was identified as a significant source of error. In the present case, this concerns in particular the assessment of the vegetation structure, because the correct determination of the coverage proportions of trees, shrubs, herbaceous and dwarf shrubs is not always guaranteed or is not in the required sharpness; this is due to the fact that the openland polygons of the FFH habitat type map often come from terrestrial mapping, e.g. biotope mapping, and usually only represent parts of Habitalp polygons, the coverage percentages of which often do not correspond to those of the subsurfaces. Finally, according to the scheme indicated in Ellmauer 2005, an overall conservation status for the Natura 2000 site and the national park is shown separately by habitat type.