The reintroduction of grey and red‐legged partridges (Perdix perdixandAlectoris rufa) in central Italy: a metapopulation approach

Abstract

The grey partridge became extinct in the province of Siena (central Italy) in the late seventies, whereas the red-legged partridge had already disappeared by the beginning of the twentieth century. Some reintroduction attempts of both species carried out in the 1980s gave encouraging but not definitive results, and failed after an initial success. This was probably due to the low number of birds released, the small size of the re-introduction areas, their isolation, the farm-bred origin of the partridges, and hunting. In the province of Siena, for the first time in Italy, a large-scale reintroduction program of grey and red-legged partridges was experimented. The project started up in 1995 with seven reintroduction areas for grey and four for red-legged partridge, and was extended to 19 areas (22,562 ha) for grey and 7 (6858 ha) for red-legged partridge in 2002. Population viability analyses for both species showed that if reintroduced populations were isolated they would be extinct in a few years. Therefore, a metapopulation approach was adopted (contemporary releases in reintroduction areas close to each other). In each area, 100-1000 partridges per year were released for a minimum of 3 years, from different farms in order to achieve the maximum initial genetic diversity. Releases were effected in late summer (August-September) in acclimatization pens containing 10-20 aviaries. The reintroduced population showed marked variability of some demographic parameters, such as pair density and brood production rate; instead, average brood size was relatively constant across the study areas, but with annual variations. Reintroduction success was limited to a few areas only, mainly depending on the habitat characteristics of the areas, their surface area and isolation, and on the degree of care for the birds during the acclimatization period.

How do different releasing techniques affect the survival of reintroduced grey partridges Perdix perdix?

“…Only a few attempts to establish a population with artificially reared birds have been successful (Ellis & Anderson 1963, Starling 1991, Panek 1988, Melin & Damange 2002, Meriggi et al 2007). Usually, successful establishment is the result of long-term release efforts with high numbers of artificially reared birds, as in the case of a region of Texas, where a population was established after the gradual release of 17,000 artificially reared pheasants during 1968-1980(Mabie 1980.…”

Mitochondrial DNA and microsatellite markers evidence a different pattern of hybridization in red-legged partridge (Alectoris rufa) populations from NW Italy

“…The risk of genetic pollution by introgressive hybridization evoked growing concern, especially for game species with high socioeconomic value. For example, wild Galliformes populations are frequently restocked with captive-Nowadays, the species mainly survives in small and highly fragmented populations in protected areas (Meriggi et al 2007). Most frequently, the occurrence of A. rufa results from continuous restocking rather than the existence of self-sustaining groups (Spano 2010).…”

Demographic parameters of reintroduced grey partridges in central Italy and the effect of weather

“…Even if the negative effects of weather on wild populations of Phasianidae can be compensated by higher productivity in favourable years, a series of several negative years acting on a small population can be fatal to the population itself. This is the case of a reintroduced population that can suffer of the typical problems of the small and isolated populations and in which the demographic stochasticity can prevent the recovery (Lacy 1992;Meriggi et al 2007). …”

“…However, the eventual decline was even more dramatic because also over-hunting acted on the already reduced productivity of populations caused by the environmental changes and by the increased use of herbicides and pesticides (Potts 1985;De Leo et al 2004;Watson et al 2007), which rendered the species endangered in a few years (Matteucci and Toso 1986;De Franceschi 1988;Meriggi et al 2007). Attempts to counteract the decline by restocking speeded up the process; in fact, initially, partridges from eastern Europe were used, which did not adapt to the local ecological conditions, and afterwards, releases of hand-reared partridges were carried out causing a further decrease in the productivity of wild populations (Putaala and Hissa 1998).…”

“…The European populations of Grey partridge (Perdix perdix Linnaeus 1758) declined from mid-1950s onwards with the reduction and the marked fragmentation of their historical range, especially along the range boundaries (Potts 1986;Potts and Aebischer 1994;Putaala and Hissa 1998;Meriggi et al 2002;Aebischer and Ewald 2004;De Leo et al 2004;Panek 2005;Meriggi et al 2007). Population decreases occurred to such an extent that the species was considered threatened and vulnerable and was classified in the list of the Species of European Conservation Concern in the third category (i.e.…”