Mapping Tropical Dry Forest Gradients in an Andean Region with High Environmental Variability

• An accurate method to map Tropical Dry Forest suitability gradients was developed. • Our map differs substantially from the official map of Dry Forest of Colombia. • We found ∼ 54 km 2 of Dry Forest in Caldas-Colombia, 9 % of its potential habitat. • Dry Forests of Caldas-Colombia are highly fragmented on private agricultural land. • Conservation of these forests needs restoration plans that engage landholders. Tropical Dry Forest (TDF) is one of the most threatened terrestrial environments in the neotropics because of high rates of conversion to agriculture. Despite this high degree of threat, many regions lack detailed maps on the actual extent and boundaries of their TDFs, which is fundamental information for their conservation. We developed a methodological framework to map TDF at 10 m in regions where they grade into other forest types. The approach uses climate variables, altitude, soil properties, and remote sensing data (multispectral and SAR − Synthetic Aperture Radar-SAR imagery) to predict TDF in the Department of Caldas, Colombia. Accuracy of the resulting map was confirmed with field observations (Overall Accuracy = 0.88, Kappa = 0.73, Area Under the Receiver Operating Characteristics Curve = 0.87, and True Skill Statistic = 0.73). We estimated ∼ 54 km 2 of TDF, which represents 9.2 % of its potential area of occurrence in the study area. TDF gradually transitions to Tropical Moist Forest (TMF) from two main low altitude river valleys to higher altitudes in the Andes Mountains. With modification, our methods could be applied for mapping TDF in other tropical regions.