Habitat models for plant functional groups with respect to soil parameters and management

ion biotope types lakes lake reeds swamp deciduous forest mixed deciduous forest mixed forest mixed coniferous forest forests and dense tree stands group of trees moist-soil meadow dry meadow grasslands calcareous dry grasslands Juniperus–stands heath beach beaches shore bank In contrast to the former biotope type, ‘dry meadows’ are not sufficiently supplied with water. The vegetation cover is closed, and compared to dry grasslands the soil is more humous and not as dry. The northern part of the Rederangkoppel belongs to this biotope type. ‘Calcareous dry grasslands’ are found on nutrient–poor alkaline soils and harbour species such as e.g. Danthonia decumbens. This is the case in parts of the Muritzwiese. The classical biotope type ‘heath’ consists of dominant dwarf–shrubs and secondary shrubs and trees. Within the investigation area a special type of heaths exists on dry and acid podsolic sandy soils, i.e. Juniperus communis–heath (or stand). It is preserved by extensive grazing and occasional shrub encroachment. 1 Note: The biotope mapping for Mecklenburg–Western Pomerania (LAUN 1995) considers the Spukloch as a ‘lake’ with an average depth of more than 5 m. According to own observations this is not the case. CHAPTER 2 STUDY SITES AND EXPERIMENTAL DESIGN 24 Beaches are the abstraction of ‘beaches’ in the closer sense and ‘shore banks’. ‘Beaches’ are part of the shore line (in this case of the Lake Muritz), whereas ‘shore banks’ are created by the surf of the lake or built up by ice movements during the winter months. They can reach heights of up to 1 m and are found along the banks of Lake Muritz. These areas are inhabited by e.g. Carex arenaria or Armeria maritima ssp. elongata. The last biotope type to be described are the abstracted forests. The ‘deciduous forest’ consists of broad– leafed trees only (e.g. Fagus sylvaticus), whereas the ‘mixed deciduous forest’ (e.g. Pinus sylvestris, Betula pendula) includes up to 30% of coniferous tree species. In contrast, the ‘mixed coniferous forests’ contains 30% of deciduous tree species. These forests are found in the north–eastern part of the investigation area. ‘Groups of trees’ are found on the Rederangkoppel. They are no larger than 0.5 ha. The ‘mixed forest’ is called ‘semi–open forest’ in Figure 2.2. A balanced mixture of deciduous (e.g. Betula pendula) and coniferous (e.g. Pinus sylvestris) tree species forms this biotope type. Except for the forest north–east of the investigation area all biotope types within the investigation area are extensively grazed. Table 2.3: Main biotope types for the Muritz investigation area. For area names see Figure 2.2. biotope characteristics utilisation area no. of plots lakes wet Spukloch reeds wet grazed Cladium-reeds 8 extremely grazed Rederangkoppel southern part, Lange Koppel 19 wet grazed Spuklochkoppel, wet grassland and reeds 23 +/-dry mowed + grazed Lange Koppel, Muritzwiese 16 grasslands dry extremely grazed Rederangkoppel northern part 16 beaches dry grazed Muritz banks 6 Juniperus-heath dry grazed Juniperus-stands, Rederangkoppel southernmost part 14 +/-dry grazed semi-open forest, dense tree stands Rederangkoppel 14 forests or dense tree stands dry not grazed Forest 4 Conservation history The nature reserve ’Ostufer der Muritz’ was created in 1949. It covers 4832 ha of lakes, wetlands, fens, mixed beech/oak forests and artificial pine forests. The central area Muritzhof (280 ha) was declared a nature reserve in 1931, but seems to have been considered one since 1911 (Deppe 1981). In 1969/70 the ’Ostufer der Muritz’ became part of the stately owned hunting ground ’Muritz’ (Jessel 2001). Nature conservation had to step back and hunting got priority. However, in 1990 the Muritz National Park was created covering 322 km2. It nowadays consists of two parts: Muritz and Serrahn. Primary objective of the national park is a free and anthropogenically unaffected nature development, i.e. natural biotic and abiotic conditions of the ecosystem are to be protected (§3 Abs. 1, NP–Verordnung). To preserve an ecosystem created by humans and their domestic animals, the historical ’treatment’ needs to be continued. The attended zone (Zone 2) maintains such special biotopes and characteristic landscapes. Part of this zone is the Muritzhof area including the Juniperus–heath, the Spukloch– and the Rederangkoppel. CHAPTER 2 STUDY SITES AND EXPERIMENTAL DESIGN