Appendix S1 – Examples of alpha hulls calculated for the observed distributions of
diadromous and non-diadromous fish species in New Zealand.
For each species, we show alpha-hulls computed using maximum triangle lengths of 50 and
200 km, i.e. all triangles with at least one side having a length greater than this critical value
are deleted. All maps use the same scaling of x and y coordinates and have the same
geographic extents.
Figure 1. Anguilla dieffenbachii, a diadromous species with an extensive geographic range
that is occupied to a high degree.
Figure 2. Galaxias fasciatus, a diadromous species with an extensive geographic range that is
occupied in a sparse fashion.
Figure 3. G. eldoni, a non-diadromous species with a very restricted geographic range.
Figure 4. G. vulgaris, a non-diadromous species with a moderately restricted geographic
range.
Figure 5. Gobiomorphus breviceps, a non-diadromous species with a moderately extensive
geographic range.