<p>Urbanization significantly alters natural ecosystems, leading to a decline in specialist species and the dominance of generalists, often exotic species. This study investigated the beta diversity of drosophilid flies across seven urban parks and three ecological reserves in the Federal District of Brazil, which is located in the core area of a biodiversity hotspot, the Cerrado biome. We examined the mechanisms of community differentiation and the relationship between community dissimilarity and the geographical distance. The analysis of over 24,000 individuals captured, representing 41 species, indicated that beta diversity between parks and reserves is driven primarily by turnover, accounting for 89% based of de variation in presence/absence data (Jaccard) and 99.9% on abundance data (Bray-Curtis). Geographical distances between the parks and reserves did not explain the dissimilarity patterns, suggesting an influence of local environmental quality and landscape heterogeneity. The dominance of a few generalists, including native and exotic species highlights the homogenization of urban communities, a process that threatens regional biodiversity. Nonetheless, the presence of <i>Drosophila willistoni</i>, an indicator of preserved environments, underscores the potential of urban parks as refuges for native biodiversity. This study highlights the need for integrated management of urban and natural ecosystems throught strategies such as ecological corridors. Although linear distance was not significant, these corridors can mitigate barriers imposed by the urban matrix and increase functional connectivity between parks and reserves, promoting more favorable dispersal routes for native species.</p>