This study explores how bee communities are distributed between urban parks and nearby natural areas over the full activity season in a Mediterranean landscape. Instead of focusing only on how many species are present, it looks at how communities are structured, how they shift between spring and late season, and what this means for pollinator conservation in increasingly urbanized environments.  

Urban parks tend to host fewer species than natural areas, particularly in the late season. This reflects broader pressures linked to urbanization, including habitat simplification and changes in floral composition. On its own, this pattern could be read as a decline in ecological value. The data suggest a more complex reality. Bee communities in urban parks are not simply reduced versions of those found in surrounding ecosystems. They are structurally different, shaped by a combination of local conditions, plant communities and seasonal resource dynamics.  

A key result of the study is that these communities are not nested. In other words, species found in urban parks are not just a subset of those found in natural areas. Instead, a large share of species shows site-specific patterns, with more than 30 percent classified as idiosyncratic. These species are often rare, with limited distribution and low abundance, but they play a central role in shaping the distinct ecological identity of each site.  

The main driver behind this pattern is species turnover. Rather than losing species across habitats, the system is characterized by replacement, with different environments hosting different assemblages. This leads to high beta diversity, meaning that the overall diversity at landscape level depends on variation between sites, not just on the richness of individual ones. Urban parks, in this context, contribute to biodiversity not by matching natural areas, but by adding complementary ecological niches.  

Seasonality plays a relevant role in shaping these dynamics. During the peak flowering period, urban parks can support bee communities comparable to those found in natural areas, particularly when they provide diverse and abundant floral resources. Later in the season, differences become more pronounced, partly due to shifts in plant composition and the presence of non-native species, which may be less attractive to certain pollinators.  

From a management perspective, the findings point to a clear direction. The ecological value of urban green spaces lies in their diversity as a system. A network of parks, distributed across the urban landscape and designed to support a range of flowering plants and nesting conditions, can sustain a broader set of species than a single, uniform space. In this sense, urban environments should not be seen only as degraded ecosystems, but as part of a mosaic where different habitats contribute in different ways to pollinator conservation.