INDIGENOUS VEGETATION TYPE AND THE DISTRIBUTION OF SHORTJAWED KOKOPU,GALAXIAS-POSTVECTIS (TELEOSTEI, GALAXIIDAE), IN NEW-ZEALAND

The shortjawed kokopu is found almost exclusively in forested catchmen ts throughout New Zealand. Forest composition appears to be important: the species is found particularly in podocarp/hardwood forests, quite often in podocarp/hardwood/beech associations, but only very rarely i n pure beech forest. Sites where shortjawed kokopu are more abundant a re always in podocarp/hardwood forest streams. Analysis of distributio n in two representative West Coast river systems, the Buller and Grey, shows that there are numerous sampled streams in beech forest catchme nts within easy reach of shortjawed kokopu migrating upstream from the sea. The shortjawed kokopu is widely present on the West Coast within the ''beech gap'', an area between 42 degrees 30' and 43 degrees 30'S , from where it is believed that all vegetation was extirpated during Pleistocene glaciations. This area is now forested by podocarp/hardwoo d associations because beech forest (Nothofagus spp.) has, as yet, bee n unable to reinvade. Reasons for this preference for podocarp/hardwoo d forest streams are not known but may relate to dietary factors or th e need for cover.