Input data: Occurrences
To train the models, georeferenced and taxonomically verified occurrences of C. mexicanus were obtained from a taxonomic study of the genus (Guevara and Sánchez-Cordero 2018). Metadata for the occurrences used in that study did not include the date of observation, which is necessary to filter the occurrences points by date. Therefore, I retrieved the capture date of each specimen from the Sistema Nacional de Información sobre Biodiversidad de México (SNIB) (Sánchez-Cordero and Guevara 2016) using the museum collection name and catalog number. To compare models between the 30-year average and different temporal resolutions (one, five, and ten years), occurrences points collected between January 1971 and December 2000 were used in model training, to match the months used to build the standard climatic normal (Fig. 3a). Occurrences points were selected per cell per month (with ”month” defined as any of the 360 months between 1971 and 2000; 30 years × 12 months). If two observations occurred in the same locality in different months (e.g., November 2000 and December 2000), both localities were retained for model training (see Supplemental material, Table S1).
I used occurrences reported outside the temporal range of the model training to evaluate the models. This second set consisted primarily of occurrences with observation dates recorded before 1971 and after 2000 from two published studies (Sánchez-Cordero and Guevara 2016, Guevara and Sánchez-Cordero 2018). Additionally, occurrences from recent literature (Hernández-Flores and Rojas-Martínez 2010, Mayen-Zaragoza et al. 2019) or recent fieldwork by colleagues and myself were incorporated into this withheld dataset. To ensure that the withheld dataset did not include occurrences near those used in model training, the withheld occurrences needed to be at a distance greater than 10 km away from a training occurrence (see Supplemental material, Table S2). Finally, a spatial thinning of 10 km was applied to reduce the spatial bias of the withheld data. Information on the environmental values assigned to the withheld dataset is explained later in the model comparison section.