Diadromy is a dominating life history strategy in the fauna, with some diadromous species being widespread beyond New Zealand, reaching Australia and/or Patagonian South America. Some species are facultatively diadromous and can establish lacustrine populations. Some are found only in lowland locations, close to the sea, whereas others penetrate greater distances inland. The presence of falls and dams excludes some diadromous species, but a few are adept at climbing falls, and may be found long distances inland. Contemporary marine straits between the main islands of New Zealand do not influence the distributions of diadromous species, though some non-diadromous species have not been able to spread across these straits. However, some non-diadromous species are present on both sides of straits, probably as a consequence of land connections across straits at a time of lowered sea-levels in the Pleistocene.