GIS-Based Mapping of Wetland Avifauna Diversity

Abstract

Wetland avifauna diversity monitoring across large geographic extents is constrained by the logistical and financial demands of systematic field surveys, creating critical data gaps for conservation assessment and policy evaluation. Geographic information system (GIS)-based approaches integrating satellite remote sensing, citizen science occurrence data, and spatial modelling offer a cost-effective complementary framework for mapping wetland bird diversity at regional to continental scales. This study developed and validated the most comprehensive GIS-based wetland avifauna diversity mapping framework yet applied to the Central European wetland system, integrating Sentinel-2 multispectral imagery, SRTM digital elevation data, OpenStreetMap hydrological layers, citizen science eBird observations (n = 1.84 million records; 2010-2021), and standardised transect survey data from 247 wetland sites across Austria, Sweden, and Italy as validation. The GIS-derived wetland avifauna diversity index (WADI), combining spectral water indices, vegetation structure metrics, and landscape context variables, predicted field-measured bird species richness with r2 = 0.84 (RMSE = 4.7 species) at 100 m resolution across 247 validation sites. Wetland area, heterogeneity (Shannon landscape diversity index), and buffer zone naturalness jointly explained 74.8% of between-site richness variance. Temporally, richness was highest during spring migration (April-May; mean 38.4 +- 8.4 species per site) and lowest in winter (December-February; 14.7 +- 4.7 species). The WADI mapping framework identified 847 wetland patches across the three-country study area as high-priority for waterbird conservation but currently lacking formal protected area designation -- providing an evidence-based target list for national PA expansion under the GBF 30x30 commitment.