How to survive as a pioneer species in the Antarctic benthos: minimum dispersal distance as a function of lifetime and disturbance

Abstract

Very few details exists concerning the dispersal traits of Antarctic species and dispersal distances in particular are mostly unknown. Especially the general low number of mesoplanktonic larvae has caught attention, leading to the formulation of Thorson’s rule. From this concept, originally concerning only trophic aspects, sometimes a reduced dispersal distance is deduced. Using a generic simulation model we show that in a benthic habitat exposed to iceberg scouring, even short dispersal phases of few hours are sufficient for a pioneer species to persist. This is very surprising for a pioneer species which should be able to disperse widely and colonise distant disturbed areas which are free of superior competitors. Our model revealed that the reason for this is the non-linear dependence of the dispersal distance on the disturbance regime and on species longevity. Thus, it is the combined effect of life history and disturbance traits which is important here: a sufficiently high disturbance frequency due to iceberg scouring and a long individual lifetime due to the low temperature decrease minimum dispersal distances required for persistence and thus coexistence and present an additional explanation for the relative rarity of planktonic larvae.

Appendix

Tables 1, and 2

Table 1 Dependency of d _min on disturbance regime; lifetime=1 d _min = ax³ + bx² + cx +d; x= disturbance radius; lifetime=1

Table 2 Dependency of d _min on lifetime d _min = d _min1 × lifetime^−b