Grazing exclusion and vegetation change in an upland grassland with patches of tall herbs

Abstract

Questions:The hydrophilous tall herb community is an important refuge for grazing-sensitive broad-leaved flowering plants. It is distributed throughout upland Europe but overgrazing has contributed to an unfavourable conservation status. To guide tall herb restoration, we asked: (a) Does using grazing exclusion where the tall herb habitat is confined to cliff ledge patches promote an expansion into the grassland below? (b) Does this management negatively affect vascular plant diversity?Location: Ben Lawers NNR, Scotland.Methods: Large herbivores have been excluded from a 180-ha area containing patches of outcrops rich in tall herb habitat. Using 1999 and 2017 surveys of permanent plot transects located in the grassland below (Before-After design), we quantify impacts on community composition and tall herb abundance.Results: Species diversity remained constant although total species richness declined slightly and tall herb species richness increased significantly. There was a large expansion in tall herb cover (+29.67%) and a corresponding decrease in grass cover (−26.16%), as well as smaller increases in bryophytes and small herbs and a reduction in bare ground. Community composition shifted significantly from species typical of upland calcareous grassland towards those found in tall herb habitats. Seven tall herb species were amongst those showing the greatest increase in cover, along with taller grasses and understory herbs. Grazing tolerant grasses and low-growing, prostrate and annual herbs decreased. Competition for light, rather than resilience to herbivory, now has a major influence on the vegetation. Conclusions:Using grazing exclusion where the tall herb habitat is largely confined to patches on cliff ledges facilitates an expansion into the upland grassland below.Although this management favours species tolerant of shadier conditions, there is no evidence of a negative impact on vascular plant community composition. It is therefore an effective strategy for promoting the restoration and favourable condition of this grazing-sensitive habitat.

Three new species of Alchemilla (Rosaceae) from northern Britain

“…On Creag na Caillich it grows in flushed species rich Nardus grassland and on grassy ledges at the base of calcareous rocky outcrops, where conditions are sheltered and soil moisture content relatively high. On Creag an Lochain, where the exclusion of large herbivores has resulted in the tall herb community expanding into the grassland below cliff ledges (Watts et al, 2019), it is locally frequent within this tall herb community, with associated species including A. glabra, A. filicaulis, A. wichurae and A. glomerulans.…”

“…Fortunately, the situation on Creag an Lochain is more promising. Here sheep were removed, and the area fenced in 2000 (Watts et al 2019); consequently, the habitat here is far more suitable, with vast swathes of A. glabra in particular, and probably the largest population of A. wichurae in the whole of Ben Lawers NNR. It seems likely that further investigations of the slopes here will reveal the species to be more numerous, at least it is to be hoped so.…”

Diversidad y enriquecimiento florístico con especies nativas de bosque mesófilo de montaña, en un bosque urbano de Chiapas, México

“…In the short follow-up of the plantation, Q. rugosa showed the highest growth rate, likely because of its tolerance to moderate shade (Quintana-Ascencio, González-Espinosa, & Ramírez-Marcial, 1992;Bonfil & Soberón, 1999). On the other hand, five species (Olmediella betschleriana, Prunus barbata, Styrax magnus, Q. crispipilis, & Q. laurina) showed a decrease in height and stem diameter, maybe associated with water stress and damage caused by passers-by that cut off growing tips, thus negatively affecting their development and, ultimately, their establishment.…”

Best served deep: The seedbank from salvaged topsoil underscores the role of the dispersal filter in restoration practice

“…weeds; Weston & Duke, 2003). Control of herbivores (e.g., using exclosures) may reduce trampling, spread of weed propagules and grazing pressure on seedlings in their early stages of emergence and establishment (Duncan & Holdaway, 1989; Schultz et al ., 2011; Watts et al ., 2019). Filters may act singly or in combination to influence community assembly, for example, land‐use legacies, such as compacted soil (abiotic filter) and weed‐dominated soil seedbank (biotic filter), can limit native plant establishment by increasing the competitive effect of dominant non‐native species (Kulmatiski et al ., 2006).…”