Do cities represent sources, sinks or isolated islands for urban wild boar population structure?

Abstract

Summary Urban sprawl has resulted in the permanent presence of large mammal species in urban areas, leading to human–wildlife conflicts. Wild boar Sus scrofa are establishing a permanent presence in many cities in Europe, with the largest German urban population occurring in Berlin. Despite their relatively long‐term presence, there is little knowledge of colonization processes, dispersal patterns or connectivity of Berlin's populations, hampering the development of effective management plans. We used 13 microsatellite loci to genotype 387 adult and subadult wild boar from four urban forests, adjacent built‐up areas and the surrounding rural forests. We applied genetic clustering algorithms to analyse the population genetic structure of the urban boar. We used approximate Bayesian computation to infer the boar's colonization history of the city. Finally, we used assignment tests to determine the origin of wild boar hunted in the urban built‐up areas. The animals in three urban forests formed distinct genetic clusters, with the remaining samples all being assigned to one rural population. One urban cluster was founded by individuals from another urban cluster rather than by rural immigrants. The wild boar that had been harvested within urban built‐up areas was predominantly assigned to the rural cluster surrounding the urban area, rather than to one of the urban clusters. Synthesis and applications. Our results are likely to have an immediate impact on management strategies for urban wild board populations in Berlin, because they show that there are not only distinct urban clusters, but also ongoing source–sink dynamics between urban and rural areas. It is therefore essential that the neighbouring Federal States of Berlin and Brandenburg develop common hunting plans to control the wild boar population and reduce conflicts in urban areas.

Secrets of Success in a Landscape of Fear: Urban Wild Boar Adjust Risk Perception and Tolerate Disturbance

“…Areas of urban forestry departments, where wild boar presence is known, was stained light green. The white circles are locations where wild boar were hunted by city hunters (for more details see Stillfried et al, 2017a) and show presence of wild boar outside the forest areas.…”

“…The biggest forest "Grunewald" is a mixed forest visited by ∼1 million people annually BDF 1 (Franusch, 2015). Although more than 1,000 wild boar are hunted every year in the Grunewald alone (Stillfried et al, 2017a), the number of wild boar remains high. Wild boar can be observed in most of Berlin's forests and adjacent built-up areas (personal observation MS).…”

“…In addition, forest patches with a known wild boar occurrence were shaded in green. Conflict wild boar which were hunted by special city hunters (Stillfried et al, 2017a) were also plotted to compare the predicted suitability with true presence (using an independent dataset).…”

“…Moreover, urban wild boar were not restricted to the edges of nature-close habitats, but could invade the urban landscape types much further. The overlap of the prediction map and map of the large forest patches that hold genetically distinct wild boar populations (Stillfried et al, 2017a) shows that the predicted areas within Berlin are actually used by wild boar (see Figure 5).…”

Moving in the Anthropocene: Global reductions in terrestrial mammalian movements

“…Stillfried et al (33) Increased productivity/reproduction, altered migration timing and increased grazing pressure at winter sites due to supplemental feeding, and population declines due to habitat loss. …”