Geodiversity-Geoconservation

Geomorphosites or groups of geomorphosites in a landscape are identified as being worth conservation (protection) on the basis of a set of weighting and ranking criteria, applied within and depending on a frame of reference of choice, which is in our work the state of Vorarlberg. Strength of this approach is that a geomorphosite which is important on a local or regional scale, but not on a global scale, can be ‘captured’ and proposed for conservation, i.e. become a potential geoconservation site, with relevance on the local or regional scale. Once a potential geoconservation site has been officially elevated by the authorities within the existing legislative framework to the status of being protected, we call it a geoconservation site.

We use four traits or factors in the quantitative part of the weighting and ranking protocol: scientific relevance, frequency of occurrence, disturbance and environmental vulnerability. Scientific relevance and frequency of occurrence are the primary traits. Being geo-ecological factors, they bear most weight in our approach.

Geomorphological Mapping

Geomorphological maps at the fine scale of 1:10.000 have been made in the field by and in cooperation with staff and students of the University of Amsterdam during many decades (de Graaff et al., 1987). These maps have been converted to digital maps in a geographical information system (GIS). Nowadays, maps are made with new techniques and modern datasets in GIS. See the sub-tab Geomorphological mapping for an overview the development of geomorphological mapping in Vorarlberg. The digital maps are input to the assessment of geoconservation potential. The computer-based protocol is illustrated below with the example of the Weienreid area in northern Vorarlberg.

Geoconservation Potential

The classes of the Tier-3 morphogenetic classification scheme have been assessed by means of the traits scientific value, frequency of occurrence, vulnerability and disturbance, and have been ranked in three classes of value (high, medium, low; see table below). The classes with high value are potential geoconservation sites. The digital geomorphological map of the Weienried area in northern Vorarlberg and the corresponding map with the geoconservation potential (below) illustrate the application.

The table above shows the quantitative assessment of the weighting and ranking criteria and the matrix for the ranking of the geoconservation potential. High significance defines a potential geoconservation site.                                                                                                                                                                    

The above map shows the final geoconservation potential of the units of the digital geomorphological map (displayed on the left) of the Weienried area. The units with high significance are potential geoconservation sites. Note that small low-lying terraces (code 2212) along the Riedbach in the southern part of the map area have been down-ranked from high to medium in a final step of the assessment.

The Weienried area in northern Vorarlberg

The area is situated around the Weienried hamlet in the municipalities of Möggers and Hohenweiler in the northernmost part of Vorarlberg at the boundary with Germany (altitude from approximately 850 m in the southeast to 480 m in the northwest). Morphologically, the area consists of two parts: a gently undulating terrain with overall slope to the northwest (see photo below) and, to the north of it, the southern flank of the deep incision of the Rickenbach. The undulating terrain is primarily a glacial-erosive landscape (morphogenetic type 1111; see above digital geomorphological map). A few morainic hills and ridges (codes 1312) occur between the hamlets of Weienried and Stadels. They are interpreted to have formed at the same time as the well-developed ice-marginal terraces at the village of Scheidegg to the north of Weienreid, across the federal boundary in Germany. They belong to the Second Recessional Complex as defined by De Jong (1983; see also De Jong et al., 1995), which formed at the end of the last, Würmian, ice age when the large Rhine Glacier was receding into the Alps from its maximum extent in the Alpine foreland of southern Germany. A mantle of subglacial till (code 1311) of varying thickness covers the bedrock in most of the area, with exposures in the smaller and larger incisions; it is absent in the western part.