Modeling Sea Turtle Nesting Probability: Evaluating Loggerhead Nest Site Selection Using Presence–Pseudo-Absence Data

Sea turtle nesting populations face growing threats from climate change, sea-level rise, and coastal development. Understanding how beach morphology influences nest-site selection is essential for effective conservation planning. This study examines loggerhead (Caretta caretta) nesting preferences on Santa Rosa Island and Perdido Key, Florida—an underutilized nesting region—using high-resolution LiDAR data from 2016 and 2020. Nest locations were paired with an equal number of pseudo-absence points, and five morphological variables were extracted: beach slope, foreshore slope, dune height, nest elevation, and nest distance from the mean higher high-water line. Logistic regression models (adjusted and unadjusted) identified nest elevation as the only variable consistently associated with nest presence, particularly in 2016. In contrast, elevation was not significant in 2020, highlighting annual variability in nesting cues. No other individual variable were significant across both years. Paired interaction analyses revealed a statistically significant and strong positive relationship between nest elevation and dune height, indicating that taller dunes increased the likelihood of nesting at higher elevations. Nest distance also significantly interacted with both dune height and beach slope, with inland nesting patterns more pronounced on steeper beaches and in areas with taller dunes. However, the positive effect of dune height weakened as beach slope increased, suggesting a trade-off between slope steepness and dune accessibility. Foreshore slope showed no meaningful direct or interactive effects. These findings highlight the complex and interrelated influences of beach morphology on nesting behavior, suggesting that loggerheads are flexible nesters across a range of physical settings but selectively respond to elevation—especially when paired with protective dune features. Conservation strategies that preserve or restore elevated nesting zones and dune structures may improve nesting success and enhance resilience in low-density nesting areas like the Florida Panhandle.