Evaluating Reliability of Habitat Suitability Index Models

The use of habitat suitability index (HSI) models is often criticized because of unreliable model performance; however, no consistent framework to validate these models exists. We offer a framework to evaluate the thoroughness of HSI model validation studies. We evaluated 17 studies that tested the reliability of 58 HSI models according to 7 criteria. The criteria included model components evaluated, input data variability, validity of comparative test(s) used, scale, range of HSIs, population index, and duration of population data collection. Guidelines that indexed the adequacy of study design were established for each criterion based on published information and past experience. All studies were deficient (maximum score was 4.05 out of 7.00 possible) according to adequacy guidelines. Most common deficiencies included inadequate consideration of input parameter variability, application of the models to inappropriate spatial scales, sampling too narrow a range of HSI values, and population data that were collected over too short a time frame.