Patterns of connectivity among populations of Cherax destructor (Decapoda : Parastacidae) in western Queensland, Australia

Abstract

Freshwater organisms are often hypothesized to reflect the hierarchical nature of stream channels in the genetic structure of their populations. However, patterns of genetic structure are also affected by the dispersal mechanism of the particular species and the nature of the river channels. In this study, the genetic structure of a freshwater crayfish, known to have the ability for terrestrial dispersal, was examined in a habitat where stream structure and elevational differences across catchment boundaries are minimal. It was found that levels of connectivity among populations in the same catchment are high, suggesting either recent or contemporary dispersal among them. In contrast, almost no sharing of haplotypes across drainage boundaries indicates limited terrestrial dispersal across them. However, nested clade analysis indicated that, historically, there has been movement between drainages. It is suggested that populations in the Cooper and Murray–Darling were isolated in the past and that, more recently, recolonization has occurred in an east–west direction from the Murray–Darling to the Bulloo and from the Bulloo to the Cooper. These movements probably occurred in wetter times when whole catchments were flooded.

A test of the vicariance hypothesis of western North American freshwater biogeography

“…These findings are supported by an unpublished allozyme survey of P. wongi , which revealed both extensive differentiation among populations ( F ST = 0.846) and sharing of alleles among isolated basins (Hamlin, 1996), and are paralleled by recent studies of aquatic biota living in other arid regions (e.g. Hughes & Hillyer, 2003; Carini & Hughes, 2004, 2006; Huey et al. , 2006).…”

Extensive intraspecific genetic diversity of a freshwater crayfish in a biodiversity hotspot

“…Within the genus Euastacus , Ponniah & Hughes (2006) postulated that the strong phylogeographic isolation between species had been caused by their extremely restricted distribution in cool upland streams. In contrast, Hughes & Hillyer (2003) observed widespread dispersal of Cherax destructor Clark, 1936 throughout catchments in inland Australia, with some historical movement across drainage boundaries. There is, however, very little comparable phylogeographic data on other Cherax species that inhabit the coastal wetlands, streams and islands of South East Queensland.…”

Mitochondrial DNA and allozymes reveal high dispersal abilities and historical movement across drainage boundaries in two species of freshwater fishes from inland rivers in Queensland, Australia

“…The results have been somewhat surprising, with significant levels of genetic diversity, both among waterholes within drainages and between drainages. This was found for four species of freshwater mussels (with glochidial larvae attaching to fins and gills of fishes)(Walker et al ., 2001, Hughes et al ., 2004), a freshwater snail (a viviparous brooder)(Carini & Hughes, in press), a crayfish (possibly capable of terrestrial dispersal)(Hughes & Hillyer, 2003) and a freshwater prawn (an apparently good swimmer)(Carini & Hughes, 2004). One explanation for these results is that although extensive flooding occurs in the area, it does not result in as much mixing of individuals as might be expected, possibly because the invertebrates are not strong swimmers and tend to remain in their waterhole of origin.…”

“…Analysis of mitochondrial DNA data for the crayfish Cherax destructor suggested, that although there was no contemporary gene flow between the Murray–Darling Basin and the Lake Eyre Basin, populations from these two major river drainages have been connected relatively recently, i.e . within the Pleistocene (Hughes & Hillyer, 2003). This result could mean either that these two drainage basins were connected at some time during the Pleistocene, or that their headwaters were closer during wetter times and some terrestrial or overland dispersal occurred (Hughes & Hillyer, 2003).…”

“…within the Pleistocene (Hughes & Hillyer, 2003). This result could mean either that these two drainage basins were connected at some time during the Pleistocene, or that their headwaters were closer during wetter times and some terrestrial or overland dispersal occurred (Hughes & Hillyer, 2003). Interestingly, a mussel species (Hughes et al ., 2004) and the freshwater prawn (Carini & Hughes, 2004) did not show similar evidence of such recent connectivity, but these species also showed more evidence of genetic structure within current drainages, so this result does not necessarily prove the drainages were not connected.…”