Landscape context and wetland attributes influence wintering waterbirds in important bird and biodiversity areas: implications for conservation and management

Abstract

Context The intensification and expansion of human activities have caused profound changes in global wetlands and their associated aquatic bird communities. Understanding the mechanisms that drive the spatial assemblages of wetland birds is important for the development of effective conservation and management strategies. Objectives The overall objective was to evaluate the influence of wetland features such as size and distance to the nearest coastline, and landscape composition, configuration, and function in shaping waterbird richness and abundance in 43 Tunisian Important Bird and Biodiversity Areas (IBAs). Methods Systematic waterbird surveys on species abundance and richness at each IBA were carried out between December and January in 2020/2021 and 2021/2022. Satellite remote sensing indices were used to map wetlands and characterize the vegetation condition in the landscape surrounding them. Landscape metrics were used to describe the habitat configuration around the wetlands. Results Our results show that landscape composition, configuration and function have significant effects on waterbirds (i.e., shorebirds, waterfowl, wading birds, and open-water birds). We found that wetland surface area and distance to the coast were important factors influencing the richness and abundance of waterbirds. Our results also indicate that landscape diversity is an important predictor of waterbird richness and abundance, and that there is a significant interaction between wetland surface area and distance to the nearest wetland in explaining the richness and abundance of waterbirds. Conclusions This study provides evidence that the richness and abundance of waterbirds are robustly dependent on the interaction between wetland surface area and distance to the nearest wetland. Furthermore, local wetland characteristics (wetland surface area and distance to the nearest coastline), landscape composition (forest area and urban area), landscape configuration (spatial heterogeneity), and landscape function (maximum and minimum NDVI), significantly affect wintering waterbird communities. This study also highlights the importance of large and connected wetlands in conserving various bird communities in Tunisian IBAs and provides recommendations for their conservation and sustainable management.