S1 Fig. The location of the five selected South African ports, and the benthic bioregions as
per Sink et al. [70].
S2 Fig. The number of ocean going vessels arriving at South African ports each year.
S3 Fig. Examples of pairwise-comparisons of the climatic conditions of ports.
S4 Fig. Examples of pairwise-comparisons of the marine environmental conditions of ports.
S5 Fig. The biogeographical regions as classified by Mead et al. [69] and the position of the
five selected South African ports.
S6 Fig. The number of ship visits, number of days travelled, marine environmental distance
and terrestrial environmental distance for the South African ports.
S7 Fig. The seasonal, relative contribution of shipping routes from foreign ports to the
marine and terrestrial establishment debt of South African ports.
S8 Fig. Seasonal variation in the number of ship visits, number of days travelled, marine
environmental distance and terrestrial environmental distance of the South African ports.
S9 Fig. The number of marine and terrestrial watch list species that might be transported
along the twenty shipping routes to each South African port with the highest relative contribution
to marine and terrestrial establishment debt.
S10 Fig. Temporal trends in the contribution of different regions to South African merchandise
imports.
S1 Table. Details of the foreign ports included in the analysis.
S2 Table. Species on the watch list developed for South Africa by Faulkner et al. [71], the
environment in which they occur (marine or terrestrial), whether they are found in climate zones or marine ecoregions that are associated with the source ports of high risk shipping
routes, and if so whether they have a history of shipping-facilitated introduction.
S3 Table. Marine and terrestrial watch list species that might be transported along the
twenty shipping routes to each South African port with the highest relative contribution
to marine and terrestrial establishment debt.
S4 Table. The relative contribution of shipping routes from foreign ports to marine and
terrestrial establishment debt.
S5 Table. The seasonal, relative contribution of shipping routes from foreign ports to the
marine and terrestrial establishment debt of South African ports.