Individual study: The relationship between ring-necked pheasant Phasianus colchicus release pen proximity and grey partridge Perdix perdix population parameters at Manydown Estate, Hampshire, England
Ewald J. A. & Touyéras H. (2002) Examining the spatial relationship between pheasant (Phasianus colchicus) release pens and grey partridge (Perdix perdix) population parameters. Zeitschrift für Jagdwissenschaft, 48, 354-363
In the UK, grey partridge Perdix perdix numbers have declined over recent decades e.g. due to agricultural intensification. In response, shooting estates have moved from management for wild grey partridges to rearing and releasing non-native ring-necked pheasants Phasianus colchicus. This has led to concern about adverse effects on grey partridges, including competition between the two species, and the possibility that parasites (especially the caecal nematode, Heterakis gallinarum) carried by pheasants may be partially responsible for grey partridge declines. Long-term monitoring data from two sites in lowland southern England were analysed to look for relationships between proximity to pheasant release pens and grey partridge population parameters. Summarised here are the results from one of these sites in Hampshire.
The dataset analysed was from the 20 kmÂ² Manydown Estate (1º9'29â€, 51º15'57â€) near the town of Basingstoke, Hampshire, southern England. Records of autumn counts of grey partridges were available for 18 years (1980-1999; 1984 and 1985 missing).
Locations of pheasant release pens were transferred onto a GIS (geographical information system). Within the GIS map four concentric bands (0-100, 100-200, 200-500 and > 500 m away) were created around release pen locations and, separately, woodland areas, for analysis.
The density of grey partridge spring pairs showed no significant trend overtime, despite the density of release pens increasing in the final years
Proximity to release pens was associated with grey partridge young-to-old ratio (averages of partridge fecundity for the four proximity bands, adjusted for year and proximity to woodland: 0-100 m from pen 0.8; 100-200 m 1.5; 200-500 m 1.7; >500 m 2.2). However, this apparent effect of pen proximity was considered probably due to habitat: 'partridge-friendly' habitats such as beetle banks and cereal crops were found away from release pens; less favoured habitats e.g. grass, winter game cover crops and natural regeneration set-aside dominated nearer the pens.
The authors concluded that there was no convincing evidence for an effect of proximity of pheasant release pens upon grey partridge population parameters.
Note: If using or referring to this published study, please read and quote the original paper, this can be viewed at: http://www.springerlink.com/content/k1t6371882637675/fulltext.pdf