Creation of micro‐topographic features: a new tool for introducing specialist species of calcareous grassland to restored sites?

Abstract

The NERC and CEH trademarks and logos ('the Trademarks') are registered trademarks of NERC in the UK and other countries, and may not be used without the prior written consent of the Trademark owner. Methods: We set up a 4-yr experiment using a split-plot design to combine pre-sowing 29 disturbance treatments at sub-plot-level (undisturbed control, glyphosate spraying, harrowing, 30 and creation of ridge-and-furrow features) with three post-establishment management regimes 31 applied at main-plot level in years 2-4, involving either summer cutting or summer cattle 32 grazing, and presence or absence of spring sheep grazing, along with autumn cattle grazing in all 33 regimes. After disturbance application, we sowed a seed mixture containing ten specialist species 34 of calcareous grassland. Using quadrat-based methods, we monitored first-year establishment 35 and subsequent dynamics, including reproductive status of species at quadrat level. Initial 36 establishment and subsequent dynamics were analysed separately using linear mixed models. 37Results: Initial establishment of sown species was promoted both by harrowing and by ridge-38 and-furrow creation. While some species were about equally promoted by both, several other 39 species benefited more strongly or exclusively from ridge-and-furrow creation. Effects of 40 disturbance largely persisted in subsequent years, but for some species, different dynamics were 41 observed for harrowed and ridge-and-furrow treatments. Thymus pulegioides and Hippocrepis 42 comosa gradually achieved higher abundances in the ridge-and-furrow treatment, in which 43 notable levels of bare ground persisted for much longer than in the harrowed treatment. In 44 contrast, Filipendula vulgaris and Pimpinella saxifraga achieved higher abundance in the 45 harrowed treatment. Sown species tended to reach reproductive stage faster in the ridge-and-46 3 furrow treatment than in the harrowed treatment. By the end of the study, management regimes 47 had resulted in few effects on species dynamics. 48Conclusions: Establishment of specialist species of calcareous grassland crucially depended on 49 bare-ground creation prior to sowing. Ridge-and-furrow creation resulted in more persistent 50 reduction of competition than the standard practice of harrowing, provided more suitable 51 conditions for low-statured specialist species, and generally enabled faster transition of 52 introduced specialist species to reproductive stage. Our results thus illustrate potential benefits of 53 using more severe disturbance when introducing specialist species of calcareous grassland at 54 restored sites. 55 56

Drought neutralises plant–soil feedback of two mesic grassland forbs

“…Calcareous grassland is highly diverse and this is mainly attributed to the poor nutrient availability and low organic matter present in the soils, which prevent dominance of one or a few species. Recent findings by Wagner et al ( 2016 ) indicate that physical disturbance of the sward, creating microsites to allow establishment of specialist species and reducing competition of generalists is crucial for creating species-rich communities in calcareous grassland. While successful establishment is critical, maintaining this species richness in the face of climate stress is frequently overlooked.…”

Evaluation of topsoil inversion inU.K.habitat creation and restoration schemes

“…However, it is precisely this reduction in ground cover that is likely to favor successful restoration. Establishment of specialist species by seeding has been shown to be more successful when bare ground conditions are created prior to sowing, with more severe soil disturbances favoring faster growth and reproduction of introduced specialist plants (Wagner et al ).…”

Human‐mediated dispersal as a driver of vegetation dynamics: A conceptual synthesis

“…Active restoration of degraded habitats, by sowing or planting species along with conservation management, is a related activity in principle, but very different in aim. In addition, subsequent colonisation of desirable species is generally anticipated, and can be encouraged by further intentional HVD such as additional sowing (Wagner et al , 2016) or movement of livestock from diverse plant communities (Freund et al , 2014).…”