Uncertainty when characterizing fundamental niche based on realized niche. A. Map of simulation study area, distribution of suitable habitat for a simulated species (black), its accessible area (M; light gray), and a plot showing ranges of mean annual temperature present in each of these areas. Note that the species' lower temperature limit is found within M, whereas its upper limit is not. B. Example of coding abiotic niche characteristics of species mapped in Figure 1a, accounting for uncertainty. Bins with values suitable to the species are marked “1”. The lower limit is found within the species' accessible area (M), so coding of bins below suitable range are coded without uncertainty (“0”). The upper limit is not found within the species' accessible area (M), so coding of bins above known suitable range are coded as uncertain (“?”)