Loss of habitat through inundation and the conservation status of two endemic Tasmanian Syncarid crustaceans: Allanaspides hickmani and A. helonomus

Abstract

Extant representatives of the ancient crustacean family Anaspididae are restricted to the island State of Tasmania, Australia. Allanaspides hickmani and Allanaspides helonomus were first described in the early 1970s from surface pools in buttongrass moorland in two adjacent watersheds in south-west Tasmania. Both of these catchments have since been inundated for hydroelectric power generation (Lake Gordon and Serpentine Impoundments). Surveys indicate that both species persist in a small number of highly fragmented populations on the margins of the two impoundments. A. hickmani and A. helonomus have extant Areas of Occupancy of c. 21 and 54 km², respectively. We estimate that inundation resulted in the loss of 85–94% of the original range of A. hickmani and c. 78% of the original range of A. helonomus. Under IUCN Red List guidelines and National threatened species legislation A. hickmani but not A. helonomus may qualify for listing as Vulnerable (Area of Occupancy <20 km²). At the present time only A. hickmani is listed as Rare under Tasmanian (State) threatened species legislation but A. helonomus merits the same listing under State legislation. Global warming appears to pose the most significant potential threat to Allanaspides species.