Drought-induced changes in hydrological and phenological interactions modulate waterbird habitats dynamics

Abstract

Floodplain wetlands are essential for the survival and reproduction of waterbirds, but droughts can negatively impact their food availability and habitat conditions, leading to a decline in waterbird abundance and diversity. To better understand the impact of hydrological and phenological variables on floodplain waterbird habitats during drought conditions, we employed hydrological modeling and remote sensing techniques to calculate fine-scale environmental variables. We constructed habitat suitability models using nine years of field surveys of waterbirds and identified the impact of the interaction effects between hydrological and phenological variables on waterbirds under drought and non-drought conditions. The results showed that hydrological and phenological variables can provide useful information for quantifying the habitat suitability of waterbirds. Drought-induced early water recession negatively impacted the quality of waterbird habitats, reducing their habitat suitability. Sedge eaters exhibited the most significant reduction of 34.47% in the total area of the lake, followed by seed eaters, fish eaters and invertebrate eaters. Tuber eaters had the largest increasing trend, with a significant increase area of 7.44% in total area. Our findings suggest that various feeding guilds exhibit distinct interactions in response to drought, which can be strengthened or weakened by alterations resulting from drought. For sedge eaters, seed eaters, and fish eaters, drought could result in a faster decline in habitat suitability by strengthening the interaction effects between variables. In contrast, for invertebrate eaters and tuber eaters, drought could weaken interaction effects between variables, resulting in a slower decline in habitat quality. The results provide valuable insights into the spatial distribution of overwintering waterbirds and can inform conservation efforts in wetlands.