Loss of biodiversity in response to the intensification of agricultural systems has been reported worldwide (see Benton et al., 2003). As arable systems are generally heavily input driven and undergo regular disturbance, they are often regarded as being simpler in form and poorer in species than are grass-based farming systems (Altieri, 1994). However, in many areas, the management practices associated with traditional grassland systems have undergone radical changes during the last 50 years e.g. the change from multi-species swards to simple Lolium-Trifolium mixtures, increased use of inorganic fertilisers (increased by 100% between 1970 and 1986 in the UK (MAFF et al, 1997)), the shift from hay to silage making and increased stocking rates (Chamberlain et al, 2000). As a result, contemporary grassland management practices are often more similar to those associated with arable systems than with those of traditional, low-input meadows, in terms of the biodiversity which they support.
Currently, semi-natural grassland (i.e. grasslands that have not been reseeded, had applications of artificial fertiliser nor have been subjected to intensive grazing or cutting during the last 45-50 years i.e. 'agriculturally unimproved grasslands' (Vickery et al, 2001)) only account for approximately 200,000ha in the UK (Crofts and Jefferson, 1999). There has been an estimated 80% reduction in their area in Sweden during the period 1870 to 1990 (Berg and Gustafson, 2007), while data for Northern Ireland reveal a 33% increase in the area under improved grassland during the period 1987 and 1998 (Cooper et al, 2003). Changes in land cover classes in the Republic of Ireland between 1990 and 2000, identified through the CORINE Land Cover assessment, include a 25% increase in land area classified within their 'arable land class' which includes land used for silage production (EPA, 2007). The inclusion of silage production areas within the 'arable land class' is notable as it reflects the similarity of management practices which occur under both farming systems. This removal and fragmentation of habitats coupled with intensive grassland management practices has resulted in increased pressure for survival on many taxa.
In recognition of their importance, many of the agri-environment schemes operating in EU now contain measures which focus on the retention and protection of field margin habitats within grassland systems e.g. Rural Environment Protection Scheme (REPS) in Ireland and Environmental Stewardship - Entry and Organic Level Stewardship in the UK. While details of individual schemes' requirements of participating farmers differ, nutrient and pesticide exclusion from these habitats is a common theme.
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