Network theory reveals priority protected areas for avian conservation in a threatened Neotropical forest-grassland mosaic

Abstract

Conserving biodiversity requires an efficiently managed network of integrated protected areas (PAs). An extensive PA network safeguards the highly threatened Araucaria angustifolia forests and associated highland grasslands of Brazil and Argentina. However, the efficiency of this network in conserving biodiversity has been poorly explored. We used complex network analysis to evaluate the efficiency of the national and state PA network conserving avian taxonomic diversity. Modularity analysis unveiled unique bird subsets in distinct PA subsets, while nestedness revealed that the most species-rich PAs in each PA subset (‘modules’) protected species in the least species-rich PAs of the same subset. Species-rich PAs within modules are a priority for conserving birds, with modules complementing each other in conserving the regional avifauna. These patterns persisted when analyzing species subsets based on forest and grassland habitat use. Additionally, we identified key PAs for the conservation of threatened species and emphasized the importance of grassland PAs in this context. Our findings support integrated PA management and may help guiding the expansion of PAs or the PA network, resource allocation and improving PA management plans. We discuss the importance of holistic conservation planning for cultural landscapes, emphasizing the well-being of Indigenous Peoples and local communities, and provide insights on implementation strategies. Our analytical framework involving multi-sourced biodiversity data collection, species incidence calculation, sampling bias assessment and network analysis can be readily adapted to evaluate PA efficiency elsewhere.