Genetic population structure defines wild boar as an urban exploiter species in Barcelona, Spain

Urban wildlife ecology is gaining relevance as metropolitan areas grow throughout the world, reducing natural habitats and creating new ecological niches. However, knowledge is still scarce about the colonisation processes of such urban niches, the establishment of new communities, populations and/or species, and the related changes in behaviour and life histories of urban wildlife. Wild boar (Sus scrofa) has successfully colonised urban niches throughout Europe. The aim of this study is to unveil the processes driving the establishment and maintenance of an urban wild boar population by analysing its genetic structure. A set of 19 microsatellite loci was used to test whether urban wild boars in Barcelona, Spain, are an isolated population or if gene flow prevents genetic differentiation between rural and urban wild boars. This knowledge will contribute to the understanding of the effects of synurbisation and the associated management measures on the genetic change of large mammals in urban ecosystems. Despite the unidirectional gene flow from rural to urban areas, the urban wild boars in Barcelona form an island population genotypically differentiated from the surrounding rural ones. The comparison with previous genetic studies of urban wild boar populations suggests that forest patches act as suitable islands for wild boar genetic differentiation. Previous results and the genetic structure of the urban wild boar population in Barcelona classify wild boar as an urban exploiter species. These wild boar peri-urban island populations are responsible for conflict with humans and thus should be managed by reducing the attractiveness of urban areas. The management of peri-urban wild boar populations should aim at reducing migration into urban areas and preventing phenotypic changes (either genetic or plastic) causing habituation of wild boars to humans and urban environments.The authors are grateful to the Ajuntament de Barcelona , who provided funding for the field sampling through the contracts 13/051 , 15/0174 , 16/0243 and 16/0243-00-PR/01 . This study benefitted from the Research Grant PID2020-115046GB-I00 Ecología, salud pública y gestión del jabalí urbano, funded by the Spanish Ministerio de Ciencia e Innovación . The Secretaria d'Universitats i Recerca del Departament d'Economia i Coneixement de la Generalitat de Catalunya and the European Social Fund funded Raquel Castillo-Contreras through the grant numbers 2016FI_B 00425 , 2017FI_B1 00040 and 2018FI_B2_00030 . The authors are also indebted to Marià Martí, Lluís Cabañeros and the rest of the Consorci del Parc Natural de la Serra de Collserola members for their logistic support. Sample collection and the related information on location would not have been possible without the essential collaboration of the local hunters from Collserola, especially Jesús Escarrà, Pere Martín, Joan Carles Montagut