Schematic procedure to estimate the loss of genetic diversity by global climate change. The species range in this fictional example is shaded in grey. Sampling sites are shown as filled circles; the colour indicates the clade found at the respective sampling site. Grid cells for SDM modelling are indicated by squares, grid cells unsuitable in the future are shaded. It is assumed that the sampling sites have been comprehensively sampled (see text). a-e) Work flow for studies especially designed for the purpose of projecting genetic diversity losses under GCC. a) sampling required to achieve comprehensive coverage of desired spatial resolution, b) test whether sampling at desired clade level was complete, c) if necessary sample the grid cells again, d) test again for completeness, e) make projections. f-i) Work flow for an existing data set. f) existing, non-systematic sampling g) determine comprehensively sampled clade level and associated appropriate sampled number of grid cells for SDM, h) determine whether effective number of sampled grid cells is actually reached with given resolution and whether spatial sampling is appropriate, i) rescale grid if necessary, if repeated rescaling does not provide satisfactory results, sample additional sites, j) make projections.