Absence of “Absences”: The Engler–Hengl Approach in Species Distribution Modeling

The possibilities of creating artificial absence points (pseudo-absences) to build species distribution models are considered. An approach proposed by R. Engler and adapted by T. Hengl is described, which takes into account habitat suitability indices and distances to presence points to create pseudo-absences. Using the example of the common bilberry (Vaccinium myrtillus) in the Central Forest Nature Reserve and its buffer zone, generalized linear models based on the Engler–Hengl approach, traveled tracks, and distances to presence points are compared, and the model built using the maximum entropy method. The results obtained indicate the superiority of the model based on the Engler–Hengl approach both in terms of quality assessments and in terms of the realism of the constructed spatial distribution maps.