Persistence in the desert: ephemeral waterways and small-scale gene flow in the desert spring amphipod, Wangiannachiltonia guzikae

Abstract

1/ The springs of the Great Artesian Basin (GAB) in central Australia support a unique, but threatened ecosystem adapted to permanent fresh water in a desert landscape. 2/ Taxa within these springs are short-range endemics, with very limited distributions, making them highly susceptible to extinction. Knowledge of fine-scale dispersal mechanisms will help to develop conservation management plans that maintain gene flow and, by extension, the genetic diversity of these populations. 3/ This study focused on determining dispersal capabilities of the endemic GAB spring amphipod, Wangiannachiltonia guzikae, in an area <4 km2. Using 11 microsatellite loci, 288 individuals were genotyped from 14 springs. 4/ Despite the very small area, low levels of gene flow and significant population differences were found among individual spring populations. Microgeographical genetic structure is clearly evident, and fine-scale dispersal is significantly correlated with temporary waterways between springs. 5/ This pattern of genetic divergence supports the stream hierarchy model of population structure and suggests that connectivity between springs is critical for gene flow, although the precise mechanism of dispersal is still open for interpretation.