The influence of management regime and altitude on the population structure of Succisapratensis: implications for vegetation monitoring

Abstract

Summary 1.Environmental change and land use may alter the vegetation typical of wetland habitats. However, commonly used techniques for vegetation monitoring that are based on species composition are often not suitable to detect gradual changes in the structure of vegetation at an early stage. In this study we tested if this methodical deficiency could be overcome by observation of the stage structure of a perennial target species. 2. We studied the density and frequency distribution of four phenological stages of the perennial plant Succisa pratensis in 24 calcareous fens in eastern Switzerland. These fens differed in management type (mowing, cattle-grazing) and altitude (low, medium, high). Among grazed fens, the intensity of management was quantified by direct observation. Species composition and canopy structure of the plant community surrounding S. pratensis were also measured. 3. High altitude had a positive effect on the density of adult plants of S. pratensis only in mown fens, whereas in grazed fens adult density was highest at medium altitude. 4. Local densities of seedlings and vegetative adults within a fen were higher in mown than in grazed fens, and lower in fens of the lowest altitude level than of the two higher ones. However, there were no differences in the relative proportions of all four phenological stages among main factors except that significantly fewer seedlings occurred in fens of the lowest altitude level. 5. It is the intensity rather than the mere type of management regime that is crucial for shaping populations of S. pratensis : for grazed fens, there is a negative relationship between intensity of grazing and density of adult plants of S. pratensis . Moreover, the number, the relative proportion of seedlings and the seed-set are all negatively correlated with grazing intensity. 6. The species composition of the plant community, but not its physical structure, was significantly related to the relative proportion of seedlings of S. pratensis , which supports the indicator qualities of the target species. 7. Monitoring the population structure of one or several target species provides important indicator information about the stability of a whole plant community. For the target-species approach we propose to use characteristic but frequently and steadily occurring species instead of rare or endangered ones.

Variation in life-cycle between three rare and endangered floodplain violets in two regions: implications for population viability and conservation

“…a high proportion of seedlings and juveniles, in response to high habitat quality (Jensen & Meyer 2001;Colling et al 2002), and especially regular land-use such as grazing or mowing (Oostermeijer et al 1994;Bühler & Schmid 2001;Lennartsson & Oostermeijer 2001;Bissels et al 2004), while populations under suboptimal conditions show a regressive stage structure, i.e. a high proportion of adult plants and no or only a few seedlings (Endels et al 2002).…”

Combining Historical and Ecological Knowledge to Optimise Biodiversity Conservation in Semi-Natural Grasslands

“…risk of being damaged, proportion of the plant removed when damaged, risk of repeated damage and risk of being damaged before completed reproduction (Lennartsson, 2002;Lennartsson & Oostermeijer, 2001). Seed production of plants decrease with increasing grazing intensity, both because of increased herbivory of reproductive organs (Bühler & Schmid, 2001;Oostermeijer et al, 2002;Pihlgren, 2007), and because of adverse effects on resistance and tolerance mechanisms (Gatehouse, 2002;Huhta et al, 2000;Huhta et al, 2003). Resistance is affected because intense grazing reduces the selectiveness of the herbivores, thereby reducing benefits of plant traits reducing palatability (Olff & Ritchie, 1998).…”

“…Growth and survival of juvenile and adult plants are also affected by disturbance intensity as a trade-off function. High intensities decrease growth and survival because of increased www.intechopen.com damage frequency (Bühler & Schmid, 2001), but increases growth and survival of rosettes and low plant stages because of reduced light competition (Lennartsson & Oostermeijer, 2001;Wallin, 2007). Grazing, in opposite to mowing, forms a mosaic of shortly grazed and tall ungrazed vegetation patches (Adler et al, 2001;Bakker, 1989;Pratt et al, 1986) due to preferences of the animals towards certain plant species and communities (Huntly, 1991;Jerling & Andersson, 1982;Putman et al, 1991), avoidance of grazing close to the faeces of conspecifics (Loucougaray et al, 2004;Ritchie & Olff, 1999) and random grazing behaviour (Brunsell, 2002;Pihlgren, 2007).…”

“…Invertebrates, birds and management-dependent vascular plants in particular have been reported to decline in spite of ongoing grassland management for conservation purposes (e.g. Boschi & Baur, 2007;Bühler & Schmid, 2001;Kruess & Tscharntke, 2002;Öckinger et al, 2006;Söderström et al, 2001;Willcox et al, 2010). Ecologically insufficient management quality is a potential threat to semi-natural grasslands that has attracted considerably less attention than has the cessation of management.…”

Resumed forest grazing restored a population of Euphydryas aurinia (Lepidoptera: Nymphalidae) in SE Finland

“…Although Succisa shoots contain alkaloids (Hultin & Torssell, 1964), which make the species unpalatable for cattle, the number of adult plants, the relative proportion of seedlings and seed-set have all been reported to correlate negatively with grazing intensity (Bühler & Schmid, 2001). In fact, Succisa was extensively grazed in the summer of 1996, especially in the northern meadow.…”