Re‐creating Semi‐natural Communities: Effect of Sowing Rate on Establishment of Calcareous Grassland

Abstract

Restoration ecologists are increasingly aware of the potential to re‐create chalk grassland on abandoned farmland. Success is often hampered by lack of desirable species in the seed bank and by poor dispersal from nearby sites. In certain schemes, the input of seed may be essential. Locally collected seed is desirable but availability is limited. We examined whether lower sowing rates than currently recommended may be successfully utilized, facilitating more‐efficient use of available seed. Experimental plots on former agricultural land were sown at different rates in a randomized complete block, and the vegetation was surveyed for two years. We compared species richness and cover for chalk grassland plants and weeds ‐ species not associated with chalk grassland communities. Values for cover and abundance were matched with data for communities of the British National Vegetation Classification (NVC). Species richness for chalk grassland plants increased with sowing rate and with time, although after two years there was no significant difference between the treatments sown at 0.4, 1.0, and 4.0 grams of seed per square meter. Weed species decreased with increasing rate and time. After two seasons, the vegetation on all treatment plots was similar to that of recognized NVC chalk grassland communities, while the controls were dominated by weeds and showed signs of developing into species‐poor grassland. Higher rates rapidly eliminated weeds, but even a small inoculum of seed seemed to significantly enhance establishment of desirable plants and to reduce weed cover. We conclude that lower sowing rates would enable the desired vegetation to become established successfully, under appropriate conditions and management regimes. Lower rates allow for the re‐creation of sizable areas using local seed, and they minimize damage to donor sites.

Grassland restoration on former croplands in Europe: an assessment of applicability of techniques and costs

“…This can be a crucial problem in the recovery of species-poor and graminoid-dominated vegetation, such as alkali grasslands (Török et al 2010b). As an alternative, seed collections may be repeated and spread across the vegetation period to maximise the number of target species (Stevenson et al 1995). The collected plant material can be applied immediately, i.e.…”

“…vacuum harvester, combine harvester; Edwards et al 2007). Though hand collection is time consuming and costly (Stevenson et al 1995), it is important when target species are located in scattered populations. When seeds of certain target species are not available in the same quantity as those of other, more common species, the sowing of LD and HD seed mixtures can be combined.…”

“…The restoration of grasslands on abandoned croplands offers a great opportunity to mitigate or halt the processes that damage grassland biodiversity (Stevenson et al 1995;Hayward 2009). Thus, grassland restoration on abandoned cropland is one of the most frequently applied habitat restoration actions in Europe (Cramer and Hobbs 2007).…”

Habitat suitability modelling for calcareous grassland restoration on the South Downs, United Kingdom

“…The botanical characteristics of these communities are summarised in Table 1. The calcareous grasslands of the South Downs are easily damaged and lost, and regeneration programs are particularly complex (Wells, 1990). The potential for natural recovery of calcareous grassland habitats principally depends upon a combination of nearby seed sources, soil of low nutrient status, and appropriate grazing management (Bobbink and Willems, 1993;Stevenson et al, 1995;Hutchings and Booth, 1996a). Dutoit and Alard (1995) stress that the re-colonisation potentials from source to target areas and dispersal constraints are the critical factors within calcareous grassland restoration programs.…”

Classification of Grassland Successional Stages Using Airborne Hyperspectral Imagery

“…The transformation of abandoned arable land into grazed grassland is expected to offer new possibilities for the establishment of species-rich and diverse grassland vegetation and to mitigate biodiversity loss in agricultural landscapes [8,9]. If species diversity in cultivated landscapes is to be maintained and enriched in the future, species will need to be able to disperse from old, species-rich grassland fragments into younger grasslands [10].…”