Understanding the variations in the potential suitable habitats of different populations of the same species is crucial for targeted biodiversity conservation and ecosystem management in specific regions. For widely distributed species, the impact of climate change on the suitable habitats of different populations may vary. However, research in this area is currently insufficient. Hippuris vulgaris is an aquatic species widely distributed across the Northern Hemisphere, with an altitudinal range from 0 to 5000 m, known for its high ecological and medicinal significance. In this study, we employed a MaxEnt model to simulate the current and future suitable habitats of H. vulgaris through constructing high-altitude, low-altitude, and integrated distribution models. The results indicated that bio3 (isothermality), bio1 (annual mean temperature), and bio19 (precipitation of coldest quarter) significantly influenced the distribution of high-altitude populations of H. vulgaris, whereas in low-altitude areas, bio3, bio9 (mean temperature of driest quarter), and bio13 (precipitation of wettest month) were the main influencing factors, and for integrated distribution populations, bio1, bio13, and bio19 were the main factors. The suitable habitat area for high-altitude populations of H. vulgaris will be increased by 19.66% in the 2050s but decrease by 47.75% in the 2070s. The suitable habitat area for low-altitude populations will be increased by 99.71% in the 2050s and by 13.29% in the 2070s. Our findings showed that the key bioclimatic variables and suitable values influencing the distribution of H. vulgaris populations in high- and low-altitude regions differed, and changes in the suitable habitats for high- and low-altitude populations showed completely opposite trends under climate change, with migration directions extending towards higher altitudes and higher latitudes, respectively.

Wetland loss and human activities are forcing migratory waterbirds to rely on alternative habitats such as croplands, yet their adaptive habitat use across contrasting landscape contexts remains unclear. The Bar-headed Goose (Anser indicus) is a key indicator species in the wetland ecosystems of the Yunnan–Guizhou Plateau. Comparing differences in its wintering habitat selection and utilization is of great significance for understanding its ecological adaptation mechanisms and formulating regional wetland conservation strategies. In this study, we compared the diurnal habitat use during the wintering period of Bar-headed Geese at three wetlands (Nianhu, Caohai, and Napahai) representing distinct landscape contexts. We used GPS satellite tracking and dynamic Brownian bridge movement modeling, combined with random forest analysis of environmental variables, to quantify diurnal habitat use and selection at each site. Our results revealed significant regional differences in habitat use. In the agriculture-dominated wetlands (Nianhu and Caohai), geese primarily utilized cropland and marsh habitats (Nianhu: cropland 45.88% ± 30.70%, marsh 42.55% ± 33.17%; Caohai: cropland 62.33% ± 12.16%, marsh 28.61% ± 13.62%). In contrast, at Napahai, which is dominated by natural habitats, geese primarily used grassland (65.92% ± 20.01%) and marsh (26.85% ± 21.88%), with minimal use of cropland (4.21% ± 7.00%). Diurnal habitat selection was influenced by multiple environmental factors, with distinct regional differences identified through random forest modeling. In Nianhu, key factors included distance to supplemental feeding site, distance to grassland, distance to woodland, and distance to open water. In Caohai, distance to grassland, distance to nocturnal roost site, distance to settlement, and distance to open water were significant drivers. In Napahai, distance to nocturnal roost site, distance to open water, and distance to marsh were the most influential (all with p < 0.01), reflecting flexible behavioral responses. Based on these findings, we recommend region-specific conservation management strategies. Specifically, supplemental feeding at Nianhu should be strictly regulated. Agricultural planning in farming areas should account for the habitat needs of wintering waterbirds. Grassland and marsh habitats at Napahai should also be more effectively protected.