Abstract

All nine lakes studied are small (mean area 32 ha), shallow (< 5 m deep), watertable exposures in thin dunes overlying laterite or sandstone. Their water is fresh (mean salinity 52 mg I^-1), acid (mean pH 4.8) and dominated by Na⁺ and Cl^-, but with appreciable amounts of Ca²⁺, Mg²⁺ and HCO₃^-. Almost all macrophytes, littoral invertebrates, fish and limnetic zooplankters are common tropical species. A few species are shared with dune lakes in southern Australia and even fewer are endemic. Hence, these tropical dune lakes are different from those in temperate and subtropical eastern Australia.