Introduction
When undertaking any reintroduction program, it is important to consider
the geographic origin between released individuals and the original
population. Introgressive hybridization between nonlocal translocated
organisms and local wild populations can have unforeseen genetic effects
on the indigenous population since it potentially affects local
adaptation in the native wild population when pairing between
translocated and native individuals takes place (Randi, 2008).
Although the grey partridge (Perdix perdix) is considered to be
common and not threatened on a global scale, its populations appear to
be declining in intensively farmed areas most likely due to a reduction
in breeding sites and food stocks (Ewald, Sotherton and Aebischer,
2020). In Europe, since the beginning of the 20th century, there has
been a drastic decline in grey partridge populations in all of the 31
countries it is found (Kuijper, Oosterveld and Wymenga, 2009). For
example, its breeding abundance fell by 92% from 1967 to 2022 across
the UK probably due to the intensification of agriculture (BirdTrends
2023, www.bto.org/birdtrends). For
this reason, the grey partridge has been Red-listed as a Bird of
Conservation Concern and the British government launched a major
programme to help partridge recovery in the UK nearly 20 years ago
(Aebischer and Ewald, 2012). Population shrinkage is also observed in
southern populations of grey partridge like Greece where, mainly from
1950 and onwards, there has been a drastic population decline
(Thomaides, C. & Papageorgiou, 1992). For this reason, the hunting of
grey partridge has been prohibited in Greece since 1984. Releases in
Greece have also taken place with farmed individuals imported mainly
from countries in the Balkans and Northern Europe of unknown provenance.
Several studies have clearly shown that the survival of hand-reared
birds is poor after their release into the wild (Liukkonen, 2006). It
has been suggested that differences in the genetic adaptation of
separate subspecies (P. p. lucida , P. p.
perdix ) to different climatic conditions of their original range could
be a partial explanation for the failed introductions (Liukkonen, 2006).
Therefore, it is of utmost importance that a genetic analysis of wild
populations is carried out.
Genetic provenance of individuals is a key assessment criterion in the
IUCN guidelines for reintroductions and translocations (IUCN 2013) as
both inbreeding and outbreeding depression are potential concerns. Some
genetic information is available for European populations of grey
partridge; phylogeographical analysis of 227 birds from several
localities based on mitochondrial DNA sequencing revealed a distinction
of populations in two major clades (western and eastern) in agreement
with the subspecies taxonomy (Liukkonen, 2006). However, little is known
about the genetics of range-edge populations, such as those in Scotland
and the Southern Balkans, Greece and North Macedonia. No individuals
have been sampled so far from Scotland while a genetic study with less
than 10 individuals from Greece revealed that the Greek population
belongs to the eastern group (Liukkonen-Anttila et al. , 2002;
Liukkonen, Kvist and Mykrä, 2012).
We use genetic analyses to study a Northern and a Southern wild and
farmed European population of grey partridge, comparing the provenance
of each. Our results will complement efforts to manage and support wild
native populations by providing important insights into the status of
these populations, namely on the levels of genetic diversity and the
impact of past restocking activities. This could have implications for
the sourcing of released birds as breeding between released stocked and
wild partridges may complicate the recovery of partridge populations.