Mowing may bring about vegetation change, but its effect is strongly modified by hydrological factors

Abstract

We assessed the effect of long-term (11 years) mowing with a hand scythe on the distributions of plant species and species turnover within meadow communities dominated by Carex acutiformis and C. acuta in a small lowland river valley subjected to annual flooding. We hypothesized that mowing would trigger the process of species exchange toward multispecies communities according to the abiotic environmental gradients, as has been reported for traditionally used wet meadows. We found that mowing had a much greater impact on the increase in plant species abundance in wetter, subjected to deeper and longer flooding, zone of the valley than in its drier part. The treatment and hydrology had no substantial effect on the sedges and cryptogams while the graminoids and the forbs were the least stable components of the plant communities. We found that annual management was conducive to the appearance of numerous seedlings of Alnus glutinosa in the part of wetland situated close to the valley edge. Surface flooding was found to be a driving force modifying the impact of mowing on sedge meadows. This ''hydrological resetting impulse'' created a specific floristic reset of the community, bringing it to the more simplified forms. Mowing every 4-5 years at the beginning of August is advisable to protect sedge meadows distributed in flooded small lowland river valleys.

Changes in functional, phylogenetic and taxonomic diversities of lowland fens under different vegetation and disturbance levels

“…Sites mown every seven to eight years seem to have supported characteristic herbaceous fen communities with the added benefit of promoting enhanced functional diversity (as was the case with the herb fen community). Our results are in accordance with other studies that found mowing every four to five years to be better at promoting the long-term sustainability of sedge meadows (Kołos and Banaszuk 2018). The intensity of grazing or mowing has been found to influence the characteristic resident flora and either the dominance of tall monocotyledons or the prevalence of small forbs and slender grasses (McBride et al 2011).…”

Leaf traits interact with management and water table to modulate ecosystem properties in fen peatlands

“…Therefore, increasing mowing intensity promoted a significant shift in the mean leaf trait composition of fen plant communities, from acquisitive, soft-leaved species to conservative, thick-leaved plants. Annual mowing of wetland habitats seems to have broad similar effects in leading to the dominance of adventitious monocots (Kołos and Banaszuk 2018), but other confounding factors like climate, topography, the length and timing of mowing and the water regime may influence the shift in functional composition reported here (Kennedy et al 2003;Zelnik and Čarni 2013).…”

Assessment and Spatial Planning for Peatland Conservation and Restoration: Europe’s Trans-Border Neman River Basin as a Case Study

“…Habitats abundantly supplied with water are mainly occupied by Phragmites australis and Carex species, while Phalaris arundinacea, Calamagrostis canescens, Alopecurus pratensis, and Deschampsia caespitosa dominate the botanical composition of drier fen variants. According to Kołos and Banaszuk [97,98], the historic transformation of fens has resulted in five dominant vegetation types (Table 4). Most open wetlands ecosystems were developed in Eastern Europe to support animal husbandry through the removal of black alder (Alnus glutinosa) wet forests on floodplains.…”