Zonation of the Liverwort Riccia in a Temporary Watercourse in Subtropical, Semiarid Australia

Abstract

The thallose liverwort Riccia formed a continuous band around the margins of shallow drainage lines at Idalia National Park, south-west of Blackall, in semi-arid, subtropical, central Queensland, Australia. Four species occurred in successive bands from the dry surrounding plain down the slope of the depressions; these were in order Riccia limbata, R. blackii, R. vesiculosa and R. multifida. When air-dry, they contributed a cover in excess of 40% in a band over 2 m wide around the depression, and apparently protected the banks from sheet flow erosion. .Riccia limbata and R. blackii are apparently poikilohydric, and may therefore provide protection for the bank at the time of the onset of rains after drought. The liverwort cover has apparently developed in the 5 years since cattle were removed from Idalia.