Bioclimatic variables
Climate data were obtained from the Terraclimate dataset, which provides monthly temperature and precipitation data at a resolution of 5 arcmin (Abatzoglou et al. 2018). The ClimateR R package (https://github.com/mikejohnson51/climateR) was used to download the climate data in R. Four bioclimatic variables – maximum temperature of the warmest month (bio05), minimum temperature of the coldest month (bio06), precipitation of the wettest month (bio13), and precipitation of the driest month (bio14) – were selected for model training. These variables were chosen based on previous studies of the species, which have established their usefulness when capturing the averages of the extreme temperature and precipitation conditions (Guevara et al. 2018).
To analyse the impact of time-matched approaches in comparison to models without time-matching, I created bioclimatic variables of different temporal resolutions. First, a single set of the standard 30-year bioclimatic average variables (STA; Fig. 1a) was created using monthly data from January 1971 to December 2000, based on a modified version of the biovars() function of the dismo R package (Hijmans et al. 2021) that use terra R package (Hijmans 2022) for faster processing. Multiple bioclimatic variables were then generated using a one-forward month moving window to explore predictions using several temporal resolutions of occurrence-environment matching. For instance, the one-year occurrence-environment matching (T01) used bioclimatic values generated within the 12 months preceding the occurrence observation, including the month of observation. Similarly, the five-year temporal resolution (T05) used 60 months, and the ten-year temporal resolution (T10; Fig. 1b) used 120 months. Environmental values for both occurrence and background points were obtained by aligning the collection date with the last month of each window period. For example, if an occurrence record was observed in January 1971, the bioclimatic values used for ten-year matching corresponded to the average of 120 months between February 1961 and January 1971.