2.3 Rule 3: we need at least 100 occurrences per species

An occurrence is non-zero observation at unique combination of site, year and period. For a stable model we need at least 100 occurrences.

58 of the 67 species have less than 100 occurrences and are thus too rare for the analysis. The final set of of species is listed in table 2.3.

Table 2.3: Number of occurrences per species.