Kimberley Fish microsatellite genotypes

Dispersal is a critically important process that dictates population
persistence, gene flow and evolutionary potential and is an essential
element for identifying species conservation risks. This project aims to
investigate the contributions of dispersal syndromes and hydrographic
barriers on patterns of population connectivity and genetic structure in
fishes occupying the particularly rugged and fragmented landscape of the
Kimberley Plateau, Western Australia. We assessed population genetic
structure between three neighbouring catchments (the Mitchell, King Edward
and Drysdale rivers) in three congeneric groups of freshwater fishes that
exhibit varied dispersal syndromes within and among groups: (1)
Melanotaenia australis and M. gracilis; (2) Syncomistes trigonicus and S.
rastellus; (3) Hephaestus jenkinsi and H. epirrhinos. Within each species
we sampled the upper, middle and lower reaches of each catchment and
assessed patterns of gene flow between and within catchments using
microsatellite markers. Our results suggest that contemporary connectivity
between catchments is greatly limited or absent in all study species,
regardless of their dispersal syndromes. However, gene flow within
catchments varied in line with predicted dispersal potential with poor
dispersers exhibiting limited gene flow and significant genetic
structuring. We conclude that the rugged landscape and historical habitat
isolation has contributed to patterns of population fragmentation among
fish populations from different river catchments. However, it appears
dispersal syndromes influence connectivity and gene flow within
catchments, where landscape constraints are not as pervasive. This study
presents a comparative population genetic analysis of freshwater fishes
with differing dispersal syndromes and colonisation ability. Our findings
provide new insights into factors shaping patterns of biodiversity on the
Kimberley Plateau, and the evolutionary uniqueness of fish communities
from different river catchments draining the plateau. The results from
this study provide a framework for informing the management of the
region’s unique freshwater biodiversity.