Habitat Suitability Analysis for Big-Headed Turtles (Platysternon megacephalum) in Ban Huak Forest, Phayao, Thailand

This research aimed to investigate the demographic characteristics and analyze the suitable habitats for Big-Headed Turtles in the Ban Huak forest area, Phu Sang Subdistrict, Phu Sang District, Phayao Province. The research methodology consisted of surveying and collecting data on Big-Headed Turtles from 51 ranges of sample streams, each 100 meters long, an analysis of information on the density and frequency of Big-Headed Turtles distribution, and an analysis of suitable habitats by applying Geographic Information System (GIS) Overlay Function combined with logistic regression equations to identify areas with a probability of 50% or higher for Big-Headed Turtles presence, indicating suitable habitats. The study found that the density of Big-Headed Turtles in the study area was 3.18 per kilometer, and the distribution frequency along the sample streams was relatively low (30.30%). The habitat suitability analysis using Logistic Regression Analysis identified that six predictive variables affecting the sighting of Big-Headed Turtles included forest type, stream order, slope, elevation, distance from community, and distance from forest protection unit with statistical significance at the 0.05 level. A Binary Logistic Regression equation was developed to analyze suitable habitats for the presence of Big-Headed Turtles with a prediction reliability of 88.24%. Suitable habitats with a 50% or higher probability of Big-Headed Turtles presence were located in the northern and northeastern parts of the study area.