Nest-site preference in captive Chinese alligators Alligator sinensis

Nest site selection occupies an extremely important place in the life history of reptiles and directly influences population persistence and reproductive success. Therefore, understanding this behavior is essential for the conservation of the endangered Chinese alligator Alligator sinensis . To investigate nest-site preferences in captive breeding environments, we surveyed 210 artificial nests across 3 breeding sites with varying management practices. Principal component analysis revealed 4 major environmental gradients (cumulative variance explained: 75.75%), with distance to water, slope length, and canopy cover contributing most to the first component (location factor), while bank height, slope angle, and platform area defined the second component (topographic factor). Habitat selection analysis showed that alligators significantly avoided nests with higher bank elevations (Vanderploeg = 0.757, p < 0.001) and steeper slopes (Vanderploeg = 0.839, p < 0.001). The best-fit generalized linear mixed model identified bank height (odds ratio = 0.383, p = 0.040) and platform area (odds ratio = 1.123, p = 0.095) as key predictors of nest utilization, with an area under the ROC curve of 0.751 and overall accuracy of 70.7%. These findings provide a scientific basis for improving the design of artificial nests, which can enhance reproductive efficiency in captive Chinese alligators and support habitat restoration efforts.