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Individual study: Evaluation of different agri-environment options on grey partridge Perdix perdix abundance

Published source details

Ewald J.A., Aebischer N.J., Richardson S.M., Grice P.V. & Cooke A.I. (2010) The effect of agri-environment schemes on grey partridges at the farm level in England. Agriculture, Ecosystems & Environment, 138, 55-63


This study is summarised as evidence for the intervention(s) shown on the right. The icon shows which synopsis it is relevant to.

Control scrub on farmland Bird Conservation

A replicated site comparison study on 1,031 agricultural sites across England in 2004-8 (Ewald et al. 2010) investigated the impact of scrub control on grey partridge Perdix perdix. However, the study does not distinguish between the impacts of scrub control, rough grazing and the restoration of various semi-natural habitats. There was a negative relationship between the combined intervention and the ratio of young to old partridges in 2008. This study investigated several other interventions, discussed in the relevant sections.

 

Control scrub Farmland Conservation

A replicated site comparison study from 2004 to 2008 on agricultural sites across England (Ewald et al. 2010) investigated the impact of scrub control on grey partridge Perdix perdix. There was a negative relationship between a combined intervention (scrub control, rough grazing and the restoration of various semi-natural habitats) and the ratio of young to old partridges in 2008. The study does not distinguish between the individual impacts of scrub control, rough grazing and the restoration of various semi-natural habitats. Spring and autumn counts of grey partridge were made at 1031 sites across England as part of the Partridge Count Scheme.

 

Take field corners out of management Bird Conservation

A replicated site comparison study on 1,031 agricultural sites across England in 2004-8 (Ewald et al. 2010) found that grey partridge Perdix perdix overwinter survival was positively correlated with taking field corners out of management, significantly so in 2007-8. There were no relationships with brood size, the ratio of young to old birds or year-on-year density changes. This study describes the effects of several other interventions, discussed in the relevant sections.

 

Take field corners out of management Farmland Conservation

A replicated site comparison study in 2004 to 2008 in England (Ewald et al. 2010) found that grey partridge Perdix perdix overwinter survival was positively correlated with taking field corners out of management, significantly so in 2007–2008. There were no relationships between taking field corners out of management and brood size, the ratio of young to old birds or year-on-year density changes. Spring and autumn counts of grey partridge were made at 1,031 sites across England as part of the Partridge Count Scheme.

Restore or create shrubland Bird Conservation

A replicated site comparison study on 1,031 agricultural sites across England in 2004-8 (Ewald et al. 2010) investigated the impact of scrub restoration on grey partridge Perdix perdix. However, the study does not distinguish between the impacts of scrub restoration, scrub control, rough grazing and the restoration of various other semi-natural habitats. There was a negative relationship between the combined intervention and the ratio of young to old partridges in 2008.

 

Undersow spring cereals, with clover for example Bird Conservation

A replicated site comparison study on 1,031 agricultural sites across England in 2004-8 (Ewald et al. 2010) found that various measures of grey partridge Perdix perdix population health declined as the amount of undersown cereal on sites increased. There were significant changes for year-on-year density changes in 2006-2007. When undersown cereals were combined with overwinter stubbles, overwinter survival rates were lower in sites with higher amounts of undersown cereals. There were no changes in brood size or the ratio of young to old birds.

 

Revert arable land to permanent grassland Bird Conservation

A replicated site comparison study on 1,031 agricultural sites across England in 2004-8 (Ewald et al. 2010) investigated the impact of the restoration of different grasslands on grey partridge Perdix perdix. However, the study does not distinguish between the impacts of grassland restoration, scrub restoration and control and rough grazing. Sites with more of the combined intervention had a lower proportion of young partridges in the population in 2008. This study describes the effects of several other interventions, discussed in the relevant sections.

 

Create beetle banks Bird Conservation

A replicated site comparison study on 1,031 agricultural sites across England in 2004-8 (Ewald et al. 2010) found that grey partridge Perdix perdix overwinter survival was significantly and positively correlated with the presence of beetle banks in 2007-8. Across all years there was a positive relationship with the ratio of young to old birds. There were no relationships with brood size or year-on-year density changes. This study describes the effects of several other interventions, discussed in the relevant sections.

 

Employ grazing in non-grassland habitats Bird Conservation

A replicated site comparison study on 1,031 agricultural sites across England in 2004-2008 (Ewald et al. 2010) investigated the impact of rough grazing on grey partridge Perdix perdix. However, the study does not distinguish between the impacts of grazing, scrub control and the restoration of various semi-natural habitats. There was a negative relationship between the combined intervention and the ratio of young to old partridges in 2008. This study describes the effects of several other interventions, discussed in the relevant sections.

 

Employ areas of semi-natural habitat for rough grazing (includes salt marsh, lowland heath, bog, fen) Farmland Conservation

A replicated site comparison study from 2004 to 2008 in England (Ewald et al. 2010) investigated the impact of rough grazing on grey partridge Perdix perdix and found a negative relationship between a combined intervention (grazing, scrub control and the restoration of various semi-natural habitats) and the proportion of young partridges in the population in 2008. The study does not distinguish between the individual impacts of grazing, scrub control and the restoration of various semi-natural habitats. Spring and autumn counts of grey partridge were made at 1,031 sites across England as part of the Partridge Count Scheme.

 

 

Convert or revert arable land to permanent grassland Farmland Conservation

A replicated site comparison study from 2004 to 2008 in England (Ewald et al. 2010) investigated the impact of restoration of different grasslands on grey partridge Perdix perdix. There was a negative relationship between a combined intervention (grassland restoration, scrub restoration and control and rough grazing) and the ratio of young to old partridges in 2008. The study does not distinguish between the individual impacts of grassland restoration, scrub restoration and control and rough grazing. Spring and autumn counts of grey partridge were made at 1,031 sites across England as part of the Partridge Count Scheme.

 

Leave uncropped, cultivated margins or plots, including lapwing and stone curlew plots Bird Conservation

A replicated site comparison study on 1,031 agricultural sites across England in 2004-8 (Ewald et al. 2010) found a lower proportion of young grey partridges Perdix perdix in the population in 2007 on sites with a large area of uncropped but cultivated margins and plots. There were no significant relationships with changes in partridge density, brood size or overwinter survival. This study describes the effects of several other interventions, discussed in the relevant sections.

 

Reduce pesticide or herbicide use generally Bird Conservation

A replicated site comparison study on 1,031 agricultural sites across England in 2004-8 (Ewald et al. 2010) found that grey partridge Perdix perdix brood size was negatively related to reduced chemical inputs, when combined with overwinter stubbles. However, this combination of interventions was positively associated with year-on-year changes in partridge density. There were no relationships with overwinter survival or the ratio of young to old birds. This study describes the effects of several other interventions, discussed in the relevant sections.

 

Employ grazing in artificial grasslands/pastures Bird Conservation

A replicated site comparison study on 1,031 agricultural sites across England in 2004-2008 (Ewald et al. 2010) found that investigated the impact of rough grazing on grey partridge Perdix perdix. However, the study did not distinguish between the impacts of grazing, scrub control and the restoration of various semi-natural habitats. There was a negative relationship between the combined intervention and the ratio of young to old partridges in 2008. This study describes the effects of several other interventions, discussed in the relevant sections.

 

Leave headlands in fields unsprayed (conservation headlands) Bird Conservation

A replicated site comparison study on 1,031 agricultural sites across England in 2004-8 (Ewald et al. 2010) found that grey partridge Perdix perdix overwinter survival was positively correlated with the proportion of a site under conservation headlands in 2007-8, and with year-on-year density changes in 2006-7. There were no relationships with brood size or the ratio of young to old birds. This study describes the effects of several other interventions, discussed in the relevant sections.

 

Leave overwinter stubbles Bird Conservation

A replicated site comparison study on 1,031 agricultural sites across England in 2004-2008 (Ewald et al. 2010) found that the ratio of young to old grey partridges Perdix perdix on sites was positively related to the proportion of sites left as overwinter stubble. However, when stubbles were used in conjunction with other interventions, the results were mixed. In conjunction with small field sizes and reduced chemical inputs, stubbles were weakly positively correlated with year-on-year changes in partridge density but negatively related to brood size. In conjunction with undersowing spring cereals, stubbles were negatively associated with year on year changes (2006-2007) and overwinter survival (2004-2005, 2005-2006 and generally). This study describes the effects of several other interventions, discussed in the relevant sections.

 

Plant grass buffer strips/margins around arable or pasture fields for birds Bird Conservation

A replicated site comparison study on 1,031 agricultural sites across England in 2004-8 (Ewald et al. 2010) found that grey partridge Perdix perdix brood size was negatively associated with the proportion of a site under planted grass buffer strips, with a significant relationship in 2008. The ratio of young partridges to old was negatively related to the proportion of grass strips in 2005 and 2008. However, year-on-year changes in partridge density and overwinter survival were positively correlated with the proportion of grass buffer strips on a site in some years - 2006 to 2007 (year-on-year changes) and 2005-6 (overwinter survival). This study describes the effects of several other interventions, discussed in the relevant sections.

 

Undersow spring cereals, with clover for example Farmland Conservation

A replicated site comparison study from 2004 to 2008 in England (Ewald et al. 2010) found measures of grey partridge Perdix perdix populations were negatively related to the proportion of sites covered by undersown spring cereals (following overwinter stubbles). There were significant negative relationships with year-on-year density changes in 2006-2007 and with overwinter survival rates in conjunction with overwinter stubbles (across all years combined and significantly in 2004-2005 and 2005-2006). There were no relationships with brood size or the proportion of young birds to old. Spring and autumn counts of grey partridge were made at 1031 sites across England as part of the Partridge Count Scheme.

 

Leave overwinter stubbles Farmland Conservation

A replicated site comparison study from 2004 to 2008 in England (Ewald et al. 2010) found that the proportion of young grey partridges Perdix perdix in the population (ratio of young to old grey partridge) was positively associated with the amount of sites left as overwinter stubble. However, when stubbles were used in conjunction with other interventions, the results were mixed. In conjunction with small field sizes and reduced chemical inputs, stubbles were weakly positively correlated with year-on-year changes in partridge density but negatively related to brood size. In conjunction with undersowing spring cereals, stubbles were negatively associated with year on year changes (in 2006-2007), overwinter survival (2004-2005, 2005-2006 and generally).

 

Leave cultivated, uncropped margins or plots (includes 'lapwing plots') Farmland Conservation

A replicated site comparison study from 2004 to 2008 in England (Ewald et al. 2010) found a lower proportion of young grey partridges Perdix perdix in the population in 2007 on sites with a high proportion of uncropped cultivated margins and plots. There were no significant relationships with changes in partridge density, brood size or overwinter survival. Spring and autumn counts of grey partridge were made at 1031 sites across England as part of the Partridge Count Scheme.

 

Create beetle banks Farmland Conservation

A replicated site comparison study from 2004 to 2008 in England (Ewald et al. 2010) found that grey partridge Perdix perdix overwinter survival was significantly and positively correlated with the presence of beetle banks in 2007-2008. Across all years there was a positive relationship with the ratio of young to old birds. There were no relationships between beetle banks and  brood size or year-on-year density changes. Spring and autumn counts of grey partridge were made at 1031 sites across England as part of the Partridge Count Scheme.

 

Pay farmers to cover the costs of bird conservation measures Bird Conservation

A replicated site comparison study on 1,031 agricultural sites across England in 2004-2008 (Ewald et al. 2010) found that in three out of four year-on-year comparisons, grey partridge Perdix perdix density changes and overwinter survival were higher on sites under  agri-environment schemes, than on sites not under schemes (density changes were more positive on agri-environment scheme sites than non-agri-environment scheme sites in all comparisons except 2007-2008; overwinter survival was higher for all except 2006-2007). However, these differences were only significant in 2005-6 for density changes (6% increase on agri-environment scheme sites vs. 11% decrease on non-agri-environment schemes sites) and 2006-2007 for overwinter survival. There were no consistent differences between agri-environment schemes and non-agri-environment scheme sites with respect to brood size. When schemes were investigated individually, only Countryside Stewardship Scheme sites and Environmentally Sensitive Areas sites had significantly more positive density trends than non-scheme sites, and only in 2005-2006 (6% increase on Countryside Stewardship Scheme and Environmentally Sensitive Areas sites vs. 12% decline on non-agri-environment scheme sites), although other years and schemes showed a similar pattern. Overwinter survival, brood size and the ratio of chicks to adults did not show consistent effects across different schemes. These individual options are discussed in the relevant sections. Various methods of succession management (rough grazing, scrub creation, scrub control, grassland creation) were negatively associated with the ratio of young to old partridges in 2008.

Plant wild bird seed or cover mixture Bird Conservation

A replicated site comparison study on 1,031 agricultural sites across England in 2004-2008 (Ewald et al. 2010) found that the proportion of young grey partridges in the population was higher in 2007 and 2008 on sites with higher proportions of wild bird cover. Brood sizes were also related to wild bird cover in 2008 only. Overwinter survival was positively related to wild bird cover in 2004-2005 but negatively in 2007-2008. There were no relationships between wild bird cover and year-on-year density trends. This study describes the effects of several other interventions, discussed in the relevant sections.

 

Plant wild bird seed or cover mixture Farmland Conservation

A replicated site comparison study from 2004 to 2008 in England (Ewald et al. 2010) found that the ratio of young-to-old grey partridges Perdix perdix was higher in 2007 and 2008 on sites with higher proportions of wild bird cover. Brood sizes were also related to wild bird cover in 2008 only. Overwinter survival was positively related to wild bird cover in 2004-2005, but negatively in 2007-2008. There were no relationships between wild bird cover and year-on-year density trends. Spring and autumn counts of grey partridge were made at 1031 sites across England as part of the Partridge Count Scheme.

 

Reduce fertilizer, pesticide or herbicide use generally Farmland Conservation

A replicated site comparison study from 2004 to 2008 in England (Ewald et al. 2010) found that reduced chemical inputs in combination with overwinter stubbles were associated with smaller grey partridge Perdix perdix brood sizes. However, year-on-year partridge density was positively associated with this combination of interventions. There was no relationship between reduced chemical inputs in combination with overwinter stubbles, and grey partridge overwinter survival or the ratio of young to old birds. Spring and autumn counts of grey partridge were made at 1,031 sites across England as part of the Partridge Count Scheme.

 

Pay farmers to cover the cost of conservation measures (as in agri-environment schemes) Farmland Conservation

A replicated site comparison study from 2004 to 2008 on 1,031 agricultural sites across England (Ewald et al. 2010) found that in three out of four year-on-year comparisons, grey partridge Perdix perdix density changes and overwinter survival were higher on sites under agri-environment schemes, than on sites not under schemes (partridge density changes were more positive on agri-environment scheme sites than non-agri-environment scheme sites in all comparisons except 2007-2008, overwinter survival was higher for all years except 2006-2007). However, these differences were only significant in 2005-2006 for density changes (6% increase on agri-environment scheme sites vs 11% decrease on non-agri-environment scheme sites) and 2006-2007 for overwinter survival. There were no consistent differences between agri-environment scheme and non-agri-environment scheme sites with respect to brood size. When schemes were investigated individually, only Countryside Stewardship Scheme sites and Environmentally Sensitive Areas sites had significantly more positive density trends than non-scheme sites, and only in 2005-2006 (6% increase on Countryside Stewardship Scheme and Environmentally Sensitive Area sites vs 12% decline on non-agri-environment scheme sites), although other years and schemes showed a similar pattern. Overwinter survival, brood size and the ratio of chicks to adults did not show consistent effects across different schemes. A higher proportion of sites under the Partridge Count Scheme implementing the options most beneficial to partridges was higher than the proportion of non-Partridge Count Scheme sites. Various methods of succession management (rough grazing, scrub creation, scrub control, grassland creation) were negatively associated with the ratio of young to old partridges in 2008.

 

Leave headlands in fields unsprayed (conservation headlands) Farmland Conservation

A replicated site comparison study from 2004 to 2008 in England (Ewald et al. 2010) found that grey partridge Perdix perdix overwinter survival was positively correlated with the proportion of a site under conservation headlands in 2007-2008, and with year-on-year density changes in 2006-2007. There was no relationship between the proportion of a site under conservation headlands and brood size or the ratio of young to old birds. Spring and autumn counts of grey partridge were made at 1031 sites across England as part of the Partridge Count Scheme.

 

Plant grass buffer strips/margins around arable or pasture fields Farmland Conservation

A replicated site comparison study in 2004-2008 across England (Ewald et al. 2010) found that grey partridge Perdix perdix brood size was negatively associated with the proportion of a site under planted grass buffer strips (association significant in 2008). The ratio of young:old partridges was negatively related to the proportion of grass strips in 2005 and 2008. However, year-on-year changes in partridge density and overwinter survival were positively correlated with the proportion of grass buffer strips on a site, this relationship was significant from 2006 to 2007 (year-on-year changes) and 2005-2006 (overwinter survival). Spring and autumn counts of grey partridge were made at 1,031 sites across England as part of the Partridge Count Scheme.