Integration of genetic and behavioural data for a restocking project. The case study of Eurasian Stone-curlew (Burhinus oedicnemus) in Morocco

A method used to prevent the decline of a species is the ex-situ conservation through reinforcement programs, where captive birds are released in areas with low population densities. A fundamental requirement of these projects is that introduced individuals must have a high affinity with wild genotypes to prevent detrimental consequences and enough genetic diversity not to compromise the ability of populations to undergo evolutionary adaptation in response to changing environmental conditions. Consequently, genetic evaluation of the captive population is essential to avoid potential genetic deleterious effects. The ultimate success of reinforcement programs is critically dependent on the ability of released animals to settle efficiently in their habitat, involving long-term survival and breeding success. All these factors can be investigated with monitoring programs using tracking devices, to support the reinforcement strategy. The Eurasian Stone-curlew (Burhinus oedicnemus) suffered a severe decline during the last century in its European range due to the degradation of its habitat and agricultural intensification. In North Africa it is also hunted by falconers. For these reasons in 2012, as a preemptive conservation strategy, the RENECO International Wildlife Consultants develops in Morocco a conservation breeding program for the species. The purpose of my study was to investigate levels of genetic differentiation between wild and captive-bred individuals used in this project and to investigate the post-release movements of captive birds. In recent years, the Stone-curlew genetic structure has been investigated by Mori et al. (2017) for populations in the western part of its distribution, revealing a significant divergence between Canary and other Mediterranean populations, but also a cryptic structure within the latter. These data were integrated to those obtained during my project to clarify this phylogeographic pattern. Genetic analyses were performed using both mitochondrial (a 652 bp fragment of the NADH2 dehydrogenase) and nuclear markers (24 microsatellites). These were analyzed in captive birds, wild birds from South-Western and South-Eastern Morocco and in birds from other populations in the western part of the species’ distribution range. Post-release movements were obtained on a sample of released birds equipped with GPS and PTTs tracking devices. I used these data to understand whether animals left the release area and at which distance from the release site they eventually settle during the breeding period. None of the analyses performed on either mitochondrial and nuclear markers showed a significative difference between wild and captive individuals, supporting a genetic compatibility between the two. Post-release movements of 22 captive Stone-curlews have been analyzed until their first reproductive period, revealing that 15 of them settled within 50 km from the release site, potentially contributing to the target population of the conservation breeding program. At a phylogeographic level, the results obtained from both markers confirmed the significant genetic differentiation between the Canary populations and the rest of the distribution range even if some analyses suggested a connection between the closest islands of Canary (Fuerteventura) and north African populations. In describing the species’ genetic structure, mitochondrial and nuclear markers showed a congruence pattern in the comparison between Canary Islands and all other populations, while nuclear DNA markers revealed a more structured pattern at a finer scale level. This study turned out to be of outstanding importance for the conservation purposes towards this species, proving that the ECWP conservation program is based on captive individuals which are compatible to wild ones and tend to remain in the surrounding area of the release site. Moreover, the integration of new genetic data to previous ones, allowed to clarify some aspect of the species’ phylogeography, in particular regarding the relationship between the Mediterranean basin and Canary Islands populations and giving us some hints about the probable origin of the latter