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Managements to achieve botanical diversification of improved grassland by natural recolonization (NATREC) - BD1452

The objective of this project is to identify extensive management regimes that will result in significant increases in botanical diversity of grasslands.
There have been very few long-term studies on the botanical diversification of grassland in agriculturally marginal areas through natural recolonization following extensification. Such research is required to identify practical cost-effective options for the creation of viable and locally relevant species-rich grasslands for agri-environment schemes.
Two projects, BD0309 and BD1424, were established in 1992 and 1995, respectively, to test the effectiveness of different extensification managements, hay cutting and/or grazing without any fertilizer inputs other than lime addition, to enhance botanical diversity. Both projects were established in mid-Wales on species-poor relatively intensively managed grassland, BD0309 on a lowland pasture at Trawsgoed and BD1424 on an upland fringe pasture at Pwllpeiran.
Changes in botanical composition, soil chemistry and herbage production were studied until 1997 in BD0309 and 1999 in BD1424 when the respective funding ceased. In the last year of monitoring it was very evident that the vegetation of all treatment plots was still in a highly dynamic state. Species indicative of agriculturally improved grassland were still common in all plots including those that showed greatest increase in species-richness. Semi-natural grassland species were establishing in plots at both sites, but the rate of natural recolonization and botanical change varied between the two sites and between the different managements. The early state of succession towards more semi-natural grassland made prediction of the type of grassland communities likely to develop under the different extensification treatments extremely uncertain. In project BD1424 liming had a major impact on plant diversity increase. However, the time-scale of the project was insufficient to allow any prediction of frequency and amount of lime that would be required to maintain the enhanced diversity to be made with any confidence. Uncertainty now exists over whether further diversity increase is being limited by edaphic conditions and/or availability of germination-establishment niches for new species or because of a lack of dispersal of seed/propagules to the restoration sites.
Results of this project will provide a basis for refinement of agri-environment management agreements on grasslands in marginal farming areas. Use of pre-existing experimental plots that have received extensive management for the typical 10-year duration of agri-environment agreements would be of particular benefit and relevance.

1. Identify extensive management regimes that will result in significant increases in botanical diversity of grasslands through natural colonization
2. Establish whether soil nutrient status and/or microbial composition are useful indicators of plant diversity restoration potential
3. Identify whether further species recruitment to extensification sites is limited by lack of availability of germination-establishment niches within plots and/or due to lack of dispersal of seed/propagules of new species to the sites
Project Documents
• Final Report : Managements to achieve botanical diversification of improved grassland by natural recolonisation   (536k)
Time-Scale and Cost
From: 2003

To: 2006

Cost: £214,513
Contractor / Funded Organisations
Institute of Grassland and Environment Research (IGER)
Environmental Protection              
Habitat conservation              
Nature conservation              
Fields of Study
Environmental Stewardship