New landscapes, new connections: How ecological network mesostructure responds to novel landscapes?

Résumé fourni par la source

Abstract Novel ecosystems created by non‐native trees cause changes in the structure of ecosystems. These changes cause disruption in ecological processes such as pollination and seed dispersion, jeopardizing these two processes that are vital for native plant communities and forest dynamics. The introduction of non‐native tree species, such as Eucalyptus globulus and Acacia dealbata , has significantly altered forests in the central region of Portugal. The resulting landscape configuration, now dominated by these two species, provides a unique setting to study how highly altered landscapes and novel ecosystems affect functional species diversity and interactions at a regional scale. Using regional data on bird‐mediated seed dispersal and pollination by birds and insects, we applied a spatial multilayer network approach to assess how these animal‐driven processes occur across different forest types (Native, Acacia and Eucalyptus ) and vary with distance between sites. By representing sites as layers connected through shared species and their interaction partners, this framework captures how interactions are linked across space and how spatial turnover in species interactions shapes network mesostructure. This network approach also allowed us to examine how landscape variables influence functional biodiversity and biotic interactions across the region. Our results show that forest type and landscape attributes are significantly associated with differences in species connectivity, functional diversity and interaction patterns across animal‐mediated processes. Specifically, connectivity and species composition varied between native and non‐native forests, while landscape complexity and land‐cover composition were associated with differences in species and interaction dissimilarity across spatial scales. These associations differed between pollination and seed dispersal networks, reflecting differences in mobility and resource use among animal groups. Synthesis: Our study suggests that landscape complexity influences functional biodiversity in pollen transport and seed dispersal at a regional scale. These findings underscore the importance of accounting for these dynamics in regional conservation and ecosystem management efforts.

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