Ecology, distribution and conservation status of wet grasslands and fens with Juncus filiformis and Eriophorum angustifolium in the Süderbergland, Westphalia.

Wet grasslands and fens are critically threatened habitats, firstly by abandonment or environmentally inappropriate farming, then possibly as a result of climate change by drying out in periods of lasting drought. To provide comprehensive information on the present species composition, ecology and conservation status of these biodiverse habitats and their plant communities in the Westphalian Süderbergland and as reference for future studies we explored which community types (associations and subunits) of wet grasslands and fens with Juncus filiformis and Eriophorum angustifolium occur in the study area, where and under which habitat and conservation conditions. It is the first study of its kind to examine wet meadow and fen communities regionwide for the entire Süderbergland. We collected 73 relevés, each with full vascular plant and bryophyte composition and mixed soil sample. We used Turboveg as database programme, Isopam as classification method, NMDS for ordination, and various statistics tools. Soil analyses included moisture, carbon and nitrogen contents, C/N ratio, CEC, pH and phosphate. Apart from soil characteristics we determined indicator values of plant species (groups) per relevé and community. We identified seven plant community types attributable to three associations. The Juncetum filiformis as an association of the Calthion palustris was found on extensively mown hay meadows chiefly around 400 m a.s.l. in the western part of the study region. The association comprised two variants distinguishable mainly by different species composition and nutrient levels. Wetlands with Eriophorum angustifolium differed from the Juncetum filiformis apart from species composition by higher soil moisture, geomorphological and soil conditions, and land-use. Two thirds of the relevés were identified as different variants of the Caricetum nigrae, distributed chiefly at headwaters between 450 and 650 m a.s.l. Subunits of the Caricetum nigrae differed mainly in nutrient levels and soil acidity. Disturbance levels indicated chiefly by various Molinietalia species played a role in determining the species richness and structure of the fen vegetation. Best-preserved fens of the Caricetum nigrae were comparably poor in vascular plant species, homogeneous in structure and rich in bryophytes. More different were acidic, pronouncedly nutrient-poor Eriophorum-rich peatmoss fens attributable to the Carici echinatae-Sphagnetum, an association of poor-fen vegetation which was recorded for the first time in the region. As a conclusion of our findings and those gathered from literature we make recommendations for conservation action regarding maintenance, restoration and connectivity. [ABSTRACT FROM AUTHOR]