Abstract: Slipper orchids (Paphiopedilum spp.) are classified as one of the most endangered orchid groups in Southeast Asia, mainly caused by habitat loss, overexploitation, and climate change. In order to establish a state of species’ conservation of this genus in Thailand, we proposed the species distribution model (SDM) based on MaxEnt v3. 4. 4 with 70 presence records and 10 predictors (climate, topography, and edaphic). The model was evaluated using 10-fold cross-validation and demonstrated good predictive power (AUCtrain =0.858; AUCtest =0.751). According to the threshold analysis, the best cloglog cut-off value was determined for 0.208, ensuring a balanced discrimination of suitable from unsuitable together with an AUC value. Under variable contributions, slope was the most important driving force (30.2%), followed by precipitation of the driest quarter (22.8%), maximum temperature of the warmest month (17.4%), elevation (11.4%) and annual precipitation 10.2%). Response curves showed ecological optima at mid-elevations (500–1500 m), moderate slopes (15–35 °), intermediate dry season rainfall, and moderate heat stress (BIO5 ≈ 28–32 °C). Spatial projections pointed to suitability hotspots in the northern mountains and southern karst regions, whereas lowlands and a large extent of the northeast were unsuitable. Our results help to elucidate the limitations of both physical and climatic factors on Paphiopedilum distribution and have implications for informed conservation decisions, including targeted field surveys, microhabitat protection and ex situ efforts.

Keywords: Paphiopedilum spp., Slipper Orchid, Species Distribution Modeling, Habitat Suitability, Environmental Predictors, Orchid Conservation, Biodiversity

Pages: 621-629