Evaluating the Suitability of using Waterbird Functional Guilds as Indicators of Climate-Driven Hydrological Impairment: A case study of Antelope Park Dam, Gweru, Zimbabwe

Abstract Wetland hydrological variability has the potential to influence waterbird communities by driving change in the availability of habitat, food resources and ecological strategies. This research sought to determine if waterbird functional guilds are useful indicators of hydrological impairment at Antelope Park Dam, Gweru, Zimbabwe. Waterbird assemblages were examined across four assessment periods (2014, 2018, 2022 and 2026), using taxonomic and functional diversity metrics, PERMANOVA and Indicator Value analysis. Species richness declined from 58 species in 2014 to 41 in 2026 (-29.3%), total abundance by 37.8% and Shannon diversity by 20.8%. Functional guild composition varied significantly among assessment periods (PERMANOVA: F, = 9.14, R = 0.43, p = 0.001). Specialist guilds showed disproportionally larger declines (piscivores (p = 0.009; -64.3%), diving birds (p = 0.028; -58.9%) and large waders (p = 0.042; approximately − 49.0%), whereas generalist feeders increased from 18.4% in 2014 to 39.7% in 2026. Functional richness, evenness and divergence declined by 42.6%, 29.2% and 35.5%, respectively. Indicator Value analysis highlighted piscivores (Ind Val = 0.82), diving birds (0.78) and large waders (0.71) as indicators of relatively good condition while generalists were associated with more degraded conditions (0.76). These trends suggest effects of environmental filtering and increasing homogenisation of functional groups. Functional metrics were more sensitive than traditional taxonomic diversity measures, confirming their utility as indicators of wetland condition, and could be used to complement traditional monitoring of semi-arid wetlands vulnerable to the impact of water extraction.