Response of breeding waders to agri-environmental schemes may be obscured by effects of existing hydrology and farming history

Published source details Kahlert J., Clausen P., Hounisen J. & Petersen I. (2007) Response of breeding waders to agri-environmental schemes may be obscured by effects of existing hydrology and farming history. Journal of Ornithology, 148, 287-293.
Share Tweet Email

Actions

This study is summarised as evidence for the following.

	Action	Category
	Raise water levels in ditches or grassland Action Link
	Revert arable land to permanent grassland Action Link
	Reduce management intensity on permanent grasslands for birds Action Link
	Convert or revert arable land to permanent grassland Action Link
	Raise water levels in ditches or grassland Action Link

Raise water levels in ditches or grassland

A replicated, controlled study in 615 grassland fields in Jutland, Denmark (Kahlert et al. 2007), found that permanent grasslands fields under an agri-environment scheme designed to increase water levels had significantly higher numbers of three species of waders (northern lapwing, black-tailed godwit Limosa limosa, common redshank) in 2004-2005 after the scheme was implemented, compared to in 1999-2001, before the scheme. However, this was only the case for fields that successfully retained water (40 pairs before and 90 after for wet fields vs. approximately two pairs before and five after for dry fields). In addition, fields that were dry before the scheme and wet after showed a greater increase (280-290% increase in lapwing numbers) than fields that were wet beforehand (130-170% increases). There were no increases on restored grasslands (formerly cropland), whether or not they were under the scheme, or on control fields (i.e. not under the scheme) that failed to retain water. Numbers did increase on control fields that retained water, but the numbers found on them were no different from those expected if increases were uniformly distributed across the landscape (i.e. birds did not appear to be selecting the fields preferentially). Eurasian oystercatchers Haematopus ostrolagus did not increase on any field types and the authors note that regional wader numbers were still far lower than in 1978-1988. The scheme involved blocking drainage pipes and ‘rills’ (drainage channels) as well as reducing the fertiliser inputs, grazing intensity and restricting when mowing could take place.
Revert arable land to permanent grassland

A replicated, controlled study in 615 grassland fields in Jutland, Denmark (Kahlert et al. 2007), found that the populations of four waders (northern lapwing Vanellus vanellus, black-tailed godwit Limosa limosa, common redshank Tringa totanus and Eurasian oystercatcher Haematopus ostrolagus) did not increase on restored grasslands (formerly croplands), whether or not they were under a scheme designed to increase water levels in fields. There were increases on some other field types. This study is discussed in detail in ‘Raise water levels in ditches or grassland’.
Reduce management intensity on permanent grasslands for birds

A replicated, controlled before-and-after study in 615 grassland fields in Jutland, Denmark (Kahlert et al. 2007), found that permanent grasslands fields under an agri-environment scheme designed to increase water levels had significantly higher numbers of three species of wader (northern lapwing Vanellus vanellus, black-tailed godwit Limosa limosa, common redshank Tringa totanus) in 2004-2005 after the scheme was implemented, compared to in 1999-2001, before the scheme. Eurasian oystercatchers Haematopus ostrolagus did not increase and effects varied between restored and permanent grasslands, and between wet and dry fields. The scheme involved promoting wet grasslands (see ‘Raise water levels in ditches or grassland’) as well as reducing fertiliser inputs, grazing pressure and the period of mowing.
Convert or revert arable land to permanent grassland

A replicated, controlled study in 2004 and 2005 in Jutland, Denmark, (Kahlert et al. 2007) found that populations of four wading birds (northern lapwing Vanellus vanellus, black-tailed godwit Limosa limosa, common redshank Tringa totanus and Eurasian oystercatcher Haematopus ostrolagus) did not increase on newly created grasslands (formerly croplands), whether or not they were under a scheme designed to increase water levels in fields. There were population increases on some other field types. A total of 615 fields were studied, comprising permanent grassland, reverted grassland and cultivated fields in rotation. The four species were surveyed twice during the breeding season (April-May), and the number of each species and their location recorded.
Raise water levels in ditches or grassland

A replicated, controlled study in 1999-2001 and 2004-2005 in Jutland, Denmark (Kahlert et al. 2007) found that permanent grassland fields under an agri-environment scheme designed to increase water levels had significantly higher numbers of three species of wading bird (northern lapwing Vanellus vanellus, black-tailed godwit Limosa limosa, common redshank Tringa totanus) after the scheme was implemented (2004-2005), compared to numbers before the scheme (1999-2001). However, this was only the case for fields that successfully retained water (40 breeding pairs of northern lapwing before the scheme and 90 after for wet fields vs approximately two pairs before and five after for dry fields). In addition, fields that were dry before the scheme and wet after showed a greater increase in lapwing numbers (280-290% increase) than fields that were wet beforehand (130-170% increase). There were no increases in lapwing numbers on restored grasslands (formerly cropland), whether or not they were under the scheme, or on control fields (i.e. not under the scheme) that failed to retain water. Numbers increased on control fields that retained water, but the numbers found on them were no different from those expected if increases were uniformly distributed across the landscape (i.e. birds did not appear to be selecting the fields preferentially). Eurasian oystercatchers Haematopus ostrolagus did not increase on any field types and the authors note that regional wader numbers were still far lower than in 1978-1988. The scheme involved blocking drainage pipes and ‘rills’ (drainage channels) as well as reducing fertilizer inputs, grazing intensity and restricting when mowing could take place. A total of 615 fields were studied. The four species were surveyed twice during the breeding season (April-May), and the number of each species and their location recorded.