Spatial changes in grey partridge (Perdix perdix) distribution in relation to 25 years of changing agriculture in Sussex, U.K

Published source details Aebischer N.J. & Potts G.R. (1998) Spatial changes in grey partridge (Perdix perdix) distribution in relation to 25 years of changing agriculture in Sussex, U.K. Gibier Faune Sauvage, Game Wildlife, 15, 293-308.
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This study is summarised as evidence for the following.

	Action	Category
	Revert arable land to permanent grassland Action Link
	Reduce pesticide or herbicide use generally Action Link
	Convert or revert arable land to permanent grassland Action Link
	Reduce fertilizer, pesticide or herbicide use generally Action Link

Revert arable land to permanent grassland

A controlled before-and-after study in 1970-94 in a 28 km² area of arable farmland in Sussex, England (Aebischer & Potts 1998), found that grey partridge Perdix perdix numbers declined rapidly on arable fields in 1987-94, following their reversion to grassland, beginning in 1987 (average of 6.5 coveys/km² in 1970-86 vs. 1.1 coveys/km² in 1987-94). There was a considerably smaller decline on arable fields that were not reverted to grassland (average of 4.9 coveys/km² in 1970-86 vs. 2.5 coveys/km² in 1987-94). The reversed fields went from being more favoured by partridges before reversion to less favoured afterwards, equating to a 23% per year decrease in relative habitat quality on the reversion fields.
Reduce pesticide or herbicide use generally

A controlled before-and-after study in 1989-94 in a 28 km² area of arable farmland in Sussex, England (Aebischer & Potts 1998), found significantly higher survival rates of grey partridge Perdix perdix chicks on 21 km² with irregular insecticide applications, compared to a 7 km²farm with insecticide applications four times a year (average of 34% survival on low application farms vs. 22% on high application farm). Before the start of intensive insecticide application (1970-88), there was no difference between areas (27% survival on low application farms vs. 30% on intensive application farm).
Convert or revert arable land to permanent grassland

A controlled before-and-after study from 1970 to 1994 in Sussex, England (Aebischer & Potts 1998), found that grey partridge Perdix perdix numbers declined rapidly on arable fields following their reversion to grassland, which began in 1987 (average 6.5 coveys (flocks)/km² in 1970-1986 vs 1.1 coveys/km² in 1987-1994). There was a considerably smaller decline on arable fields that were not reverted to grassland (average 4.9 coveys/km² in 1970-86 vs 2.5 coveys/km² in 1987-1994). Fields that were reverted had been favoured by partridges prior to reversion, in comparison to arable fields, but were less favoured after reversion, equating to a 23% per year decrease in relative habitat quality. Fields in a 28 km² area were surveyed for grey partridges in late August/early September after the autumn harvest by driving across fields at dawn and dusk and mapping the position of each observation.
Reduce fertilizer, pesticide or herbicide use generally

A site comparison before-and-after study from 1989 to 1994 in Sussex, England (Aebischer & Potts 1998) found that survival rates of grey partridge Perdix perdix chicks were significantly higher on 21 km² of arable farmland that received irregular insecticide applications, compared to a 7 km² farm with insecticide applications four times a year (average 34% survival on low application farms vs 22% on high application farm). Before the start of intensive insecticide application (1970-1988), survival on the farm had been similar to, or higher than, that on the surrounding farms (27% survival on low application farms vs 30% on intensive application farm). Chick survival rates (up to the age of approximately six weeks) were calculated each year and compared between areas with intensive and irregular insecticide applications. A long-term data set (1970-1988) collected prior to this study was used to investigate chick survival prior to insecticide application on the intensive application farm.