Habitat requirements and distribution of Engaeus cisternarius and three subspecies of Parastacoides tasmanicus (Decapoda : Parastacidae), burrowing crayfish from an area of south-western Tasmania

Abstract

During an extensive survey of the crayfish fauna of the lower catchments of the Gordon River, south-western Tasmania. two species of crayfish were collected: Engaeus cisternarius and three subspecies of Parastacoides tasmanicus (P. t. tasmanicus, P. t. inermis and P. t. insignis). From this survey and an intensive study in a small area of the Olga River valley, distinct habitat preferences of each of the forms were recognized. E. cisteinavius was restricted to the areas north and west of the Gordon River where it was found only in clay and sandy soils under rainforest. P. t. tasmanicus was found in waterlogged soils, peats and sands on valley floors covered either with wet sedgeland or rainforest. P. t. inermis was found in two disjunct habitats: well- drained slopes and hillsides covered in heath vegetation. and under rocks in small creeks in rainforests. P. t. insignis occupied an intermediate habitat between P. t. tasmanicus and the non-creek dwelling, P. t. inermis, but was restricted geographically to the extreme south-west of the study area.

The taxonomic status of the P. tasmanicus subspecies is discussed.