Genetic Diversity and Population Structure of Urban and Rural Goshawks.

Abstract

Urbanization poses a growing threat to biodiversity with potential impacts on species' genetic diversity and population structure. The Eurasian goshawk (Astur gentilis) is traditionally a forest-dwelling raptor that has recently established breeding populations in urban environments such as Helsinki, Finland. Here, we investigated genetic diversity and population structure across urban, suburban, and rural goshawk populations in Finland using 10 microsatellite markers and 72 individuals sampled between 1990 and 2020. Genetic diversity, measured by heterozygosity and allelic richness, was similar among populations. Genetic differentiation was low to moderate (F ST = 0.022-0.074) and statistically non-significant. Despite urbanization, contemporary urban goshawks showed genetic similarity to adjacent contemporary non-urban goshawks, while greater differentiation was observed between temporally separated populations. Consistent with this pattern, clustering supported K = 2 as the primary level of genetic structure, separating the contemporary urban and surrounding populations from the earlier surrounding and rural populations. Given the limited marker set and sample sizes, these findings are interpreted as broad-scale patterns rather than definitive evidence of fine-scale population structure. Further studies using larger sample sizes and genome-wide markers are needed to resolve population connectivity and the longer-term genetic effects of urbanization.