Slide 12: Specifics: Niche-based modelling
How does niche-based modelling work? Firstly, the series of points at which a species has been observed (the species distribution) is projected onto a series of environmental layers, to get a dataset of variables at known locations of the species. If an independent evaluation dataset is available, the model can be calibrated using the training data. If not, the dataset needs to be divided into two separate datasets: one for calibrating the model, and a second (smaller) one to evaluate the accuracy of the model. The model is then calibrated, and the accuracy of the model is evaluated by determining how well it operates for the evaluation dataset. Evaluation is done by means of a confusion matrix, as shown. If the model is not shown to perform suitably well, it needs to be refined, otherwise it can then be used to predict current and future distributions.