Response of spring wetlands to restored aquifer pressure in the Great Artesian Basin, Australia

Abstract

• Water extraction has reduced aquifer pressure in the Great Artesian Basin, Australia. • Flows to springs have declined but endemic species have survived. • Open drains have been replaced by polyethylene pipe restoring aquifer pressure. • Spring wetlands have expanded and management implications are discussed. • Decline in aquifer pressure, loss of springs and then recovery provides lessons for the world. The decline in aquifer water tables resulting from groundwater extraction and the impacts on spring ecosystems is a recurring management issue throughout the world. This study from the Great Artesian Basin in Australia demonstrates how water extraction through uncapped (open) bores since the late nineteenth century has reduced aquifer pressure, dewatering many natural springs. Flow rates to one spring complex at Pelican Creek also declined, but an extraordinary array of endemic species have persisted. At Pelican Creek an extremely rare endemic fish, the red-finned blue-eye ( Scaturiginichthys vermeilipinnis ) is threatened with extinction from predation by an exotic fish gambusia ( Gambusia holbrooki ). A government-funded program to cap flowing bores and to replace the distribution of groundwater through open drains with polyethylene pipe has resulted in the partial restoration of aquifer pressure coinciding with the expansion of spring wetlands. The restoration of springs enhances habitat for spring-dependent endemic species, but also makes the removal of gambusia more difficult and the opportunities for dispersal into the few remaining springs free of gambusia more likely. The documentation of the decline in aquifer pressure and loss of springs, followed by pressure recovery with aquifer management, and local management of springs provides lessons for the parallel circumstances throughout the globe.