Wetting up farmland for birds and other biodiversity

Published source details Defra (2007) Wetting up farmland for birds and other biodiversity. Defra BD1323 report. Defra, BD1323.
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Actions

This study is summarised as evidence for the following.

	Action	Category
	Manage ditches to benefit wildlife Action Link
	Create scrapes and pools Action Link
	Raise water levels in ditches or grassland Action Link
	Manage ditches to benefit wildlife Action Link
	Create scrapes and pools in wetlands and wet grasslands Action Link
	Exclude livestock from semi-natural habitat (including woodland) Action Link
	Employ grazing in artificial grasslands/pastures Action Link
	Raise water levels in ditches or grassland Action Link

Manage ditches to benefit wildlife

A replicated, controlled and paired sites study of bunded and non-bunded drainage ditches in arable and pastoral areas of Leicestershire, UK (Defra 2007), found that bird visit rates were significantly higher in bunded compared to non-bunded ditches (1.0 vs. 0.5 visits/month). Sampling involved bird observations (45 minutes, 1-2/month between April 2005 and March 2007.
Create scrapes and pools

A replicated, controlled paired study of eight created ditch-fed paired ponds in field corners and ten surface scrapes in arable field margins in Leicestershire, UK (Defra 2007) found that bird visit rates were significantly higher in ditch-fed paired ponds (1 visit/month) than dry controls (0.5 visits/month), particularly in the summer months; sample sizes were too small to analyse visits to scrapes. Paired ponds in field corners are fed with water from a nearby ditch. Surface-active adult flies (Diptera) were more abundant and fly larvae and butterfly/moth (Lepidoptera) larvae (in 2005) less abundant in the scrapes than the controls. Numbers of invertebrates active in the grass layer were lower in scrapes than nearby unmanipulated plots. Vegetation was more heterogenous (diversity and height), grass cover lower and bare ground more extensive in the scrapes than the control areas. Sampling involved bird observations (45 minutes, 1-2/month), pitfall traps and sweep-netting for terrestrial invertebrates (scrapes) and botanical quadrat (0.25-0.5m²) survey (scrapes). Data was obtained between April 2005-March 2007; birds all year, other groups spring-summer.
Raise water levels in ditches or grassland

A replicated, controlled (paired) study of wet pasture and bunded and non-bunded drainage ditches in arable and pastoral areas in Leicestershire, UK (Defra 2007), found that bird visit rates were significantly higher in wet pasture (0.2-0.3 visits) than in control dry plots (0.1), particularly in the summer months and in 2006. The authors suggested benefits due to management may increase over time. Visit rates were also higher to ditch-fed paired ponds (1.0 visit/month) than dry controls (0.5 visit/month). Sampling involved bird observations (45 minutes, 1-2/month between April 2005 and March 2007.
Manage ditches to benefit wildlife

A replicated, controlled (paired) study of drainage ditches in arable and pastoral areas of Leicestershire, UK (Defra 2007) (same study as (Aquilina et al. 2007)) found that that wetting-up ditches resulted in higher invertebrate and bird numbers. The following were significantly greater in bunded (dammed ditches) compared to non-bunded ditches: bird visit rates (1.0 vs 0.5 visits/month), emergent aquatic insect biomass (1,400 vs 900 individuals/m²), surface-active fly (Diptera) adults (in arable ditches in 2005; 85-100 vs 60-65/sample) and fly larvae and butterfly/moth (Lepidoptera) larvae (in pastoral ditches in 2006). There was no difference for invertebrates active in the grass layer. Vascular plant species richness was lower and bare ground cover higher in bunded ditches than controls in 2005 due to disturbance during creation. Sampling involved bird observations (45 minutes, 1-2/month), fixed/floating traps for emerging aquatic insects, pitfall traps and sweep-netting for terrestrial invertebrates and a botanical quadrat (0.25-0.5m²) survey. Data was obtained between April 2005-March 2007; all year for birds and spring-summer for other groups.
Create scrapes and pools in wetlands and wet grasslands

A replicated, controlled paired sites study of wet pasture and bunded and non-bunded drainage ditches in arable and pastoral areas in Leicestershire, UK (Defra 2007), found that bird visit rates were significantly higher in wet pasture (0.2-0.3 visits) than in control dry plots (0.1), particularly in the summer months and in 2006. The authors suggested benefits due to management may increase over time. Visit rates were also higher to ditch-fed paired ponds (1.0 visit/month) than dry controls (0.5 visit/month). Sampling involved bird observations (45 minutes, 1-2/month between April 2005 and March 2007.
Exclude livestock from semi-natural habitat (including woodland)

A replicated, controlled (paired) study of wet pasture in Leicestershire, UK (Defra 2007) found that bird visit rates were significantly higher in areas with livestock (wet plots: 0.26, dry: 0.10) than in those where livestock had been excluded (wet: 0.17, dry: 0.06). Sampling involved 45 minute bird observations between April 2005-March 2007 (twice/month April-October, once/month November-March).
Employ grazing in artificial grasslands/pastures

A replicated, controlled, paired sites study of wet pasture in Leicestershire, UK (Defra 2007), found that bird visit rates were significantly higher in areas with livestock than in those where livestock had been excluded. Sampling involved 45 minute bird observations between April 2005-March 2007 (twice/month April-October; once/month November-March).
Raise water levels in ditches or grassland

A replicated, controlled (paired) study of wet pasture and drainage ditches in arable and pastoral areas in Leicestershire, UK (Defra 2007) (same study as (Aquilina et al. 2007)) found that wetting-up resulted in higher invertebrate and bird numbers. The following were significantly higher in bunded (dammed ditches) compared to non-bunded ditches: bird visit rates (1.0 vs 0.5 visits/month), emergent aquatic insect biomass (1,400 vs 900 individuals/m²), surface-active flies (Diptera) adults (in arable ditches in 2005; 85-100 vs 60-65/sample) and fly larvae and butterfly/moth (Lepidoptera) larvae (in pastoral ditches in 2006). There was no difference for invertebrates active in the grass layer. Vascular plant species richness was lower and bare ground cover higher in bunded ditches than controls in 2005 due to disturbance. In wet pasture, bird visit rates were significantly higher (livestock: 0.26, livestock-excluded: 0.17 visits) than in control dry plots (livestock: 0.10, livestock-excluded: 0.06). Sampling involved bird observations (45 minutes, 1-2/month; both features), fixed/floating traps for emergence of aquatic insects (ditches), pitfall traps and sweep-netting for terrestrial invertebrates (ditches) and a botanical quadrat survey (0.25-0.5m²; ditches). Data was obtained between April 2005-March 2007; birds all year, other groups spring-summer.