*2.4. Calculating Percent Change of Geographic Distribution and Model Evaluation*

The difference in distribution between the present distribution model and each respective future climate change binary model was calculated in km2 through ArcGIS as each pixel has a spatial resolution of 1 km2. Consequently, the percentage of change in geographic distribution was calculated for each climate change scenario by subtracting the amount of suitable habitat for *M. walkerae* in km2 from the amount of unsuitable habitat within the study area which was then multiplied by a 100 and divided by the present suitable habitat (Table 2).


**Table 2.** Percent change of geographic distribution for *Manihot walkerae* between the current model and the future projected climate change models for the years 2050 and 2070.

Receiver Operating Characteristics (ROC) were used to evaluate the model based on the area under the curve (AUC) and partial ROC (pROC) values. The AUC is used to evaluate a model's predictive ability where values range from 0 to 1, with those closer to 1 indicating models with a good predictive ability and a value of 0.5 representing a random predictive ability [44]. However, the reliability of the AUC to evaluate models has been brought into question for several reasons summarized by Lobo et al. (2007) [45]. Therefore, we also calculated pROC as an additional statistic to evaluate the model [46] using NicheToolbox, an application that facilitates its calculation [47].
