Genetic structure and diversity of introduced eastern mosquitofish (Gambusia holbrooki) in south-eastern Australia

2012 ◽  
Vol 63 (12) ◽  
pp. 1206 ◽  
Author(s):  
Renae M. Ayres ◽  
Vincent J. Pettigrove ◽  
Ary A. Hoffmann
Keyword(s):  
Published Data ◽  
Gambusia Holbrooki ◽  
Historical Records ◽  
Genetic Structuring ◽  
South Eastern ◽  
Introduced Range ◽  
Eastern Australia ◽  
Eastern Mosquitofish ◽  
Microsatellite Diversity ◽  
South Eastern Australia

The closely related eastern mosquitofish (Gambusia holbrooki) and western mosquitofish (Gambusia affinis) have been introduced into many countries and collectively represent the most widely distributed freshwater fish in the world. We investigated genetic patterns associated with the spread of G. holbrooki in its introduced range in south-eastern Australia, by sampling 60 G. holbrooki populations (n = 1771) from major regions where G. holbrooki was initially introduced into Australia, and characterising the genetic diversity and population structure of G. holbrooki, using five polymorphic nuclear microsatellite loci and sequences from two mitochondrial genetic markers. Results were compared with published data on American and European Gambusia samples and historical records. Low microsatellite diversity and strong population genetic structuring were found within G. holbrooki in south-eastern Australia. Observed heterozygosity and allelic richness declined regionally in the order Sydney, Brisbane, Canberra, Melbourne and Adelaide. Microsatellite variation in Australia was reduced compared with native populations. Two mitochondrial DNA haplotypes of G. holbrooki were found; one was common, whereas the other was detected in one Sydney population and one Melbourne population. Cytochrome b sequence diversity was reduced compared with native and European ranges, and sequences were identical to two haplotypes previously identified. Microsatellite diversity of G. holbrooki in south-eastern Australia validates historical records of its spread, beginning north and moving south. Mitochondrial sequencing confirms that G. holbrooki is present in Australia, but the origins of Australian G. holbrooki populations remain unclear.

Do invasive eastern gambusia (Gambusia holbrooki) shape wetland fish assemblage structure in south-eastern Australia?

2012 ◽  
Vol 63 (8) ◽  
pp. 659 ◽  
Author(s):  
Jed I. Macdonald ◽  
Zeb D. Tonkin ◽  
David S. L. Ramsey ◽  
Andrew K. Kaus ◽  
Alison K. King ◽  
...  
Keyword(s):  
Native Species ◽  
Ecological Impacts ◽  
Life History Strategies ◽  
Ecological Niches ◽  
Gambusia Holbrooki ◽  
Fish Assemblage Structure ◽  
South Eastern ◽  
Eastern Australia ◽  
Specialist Species ◽  
South Eastern Australia

Defining the ecological impacts conferred by invasive fishes provides a framework for evaluating the feasibility of control efforts in invaded waterways, and for predicting the consequences of future incursions. Eastern gambusia (Gambusia holbrooki) is a remarkably successful invader of freshwater systems worldwide, with the capacity to detrimentally impact native fishes both directly (e.g. competition, predation, agonistic interactions) and indirectly (e.g. triggering trophic cascades). Here, we modelled the influence of eastern gambusia and several environmental covariates on fish species diversity, abundance and condition based on quantitative survey data collected from 93 wetlands in south-eastern Australia. We predicted that small-bodied, wetland specialist species sharing dietary- and habitat-niches with eastern gambusia would be most severely impacted, and that environmental stressors associated with wetland drying during late summer would magnify these impacts. Eastern gambusia influenced the occurrence, abundance and/or body condition of most common wetland species; however, the direction and level of impact appeared dependent on both biotic and environmental forces. From these results, we postulate that generalist life-history strategies that permit niche-segregation may release some native species from competitive/predatory pressures, allowing coexistence with eastern gambusia in resource-limited, environmentally harsh habitats, whilst specialist species that occupy narrower ecological niches may be less resistant.

Distribution and identity of species in the Antechinus stuartii - A. flavipes group (Marsupialia : Dasyuridae) in south-eastern Australia

1998 ◽  
Vol 46 (1) ◽  
pp. 27 ◽  
Author(s):  
J. Sumner ◽  
C. R. Dickman
Keyword(s):  
New South ◽  
New South Wales ◽  
Annual Rainfall ◽  
Published Data ◽  
South Eastern ◽  
Mean Annual Rainfall ◽  
South Wales ◽  
Eastern Australia ◽  
Antechinus Stuartii ◽  
South Eastern Australia

This study describes genetical differences between three morphologically similar species of Antechinus in south-eastern Australia, and uses the climatic model BIOCLIM to clarify their expected geographical distributions. Allozyme electrophoresis revealed Nei’s distances of >0.2 between A. flavipes and A. stuartii and A. flavipes and A. agilis, the latter a newly recognised species in south-eastern Australia. Fixed allele differences were determined in five proteins between A. stuartii and A. flavipes from an area of sympatry in northern New South Wales, confirming their genetic distinctness. A smaller distance (0.08) separated A. stuartii from A. agilis, but fixed allele differences in albumin and mannose phosphate isomerase distinguished these species clearly. Locality records for the three species were compiled from the electrophoretic results, museum specimen records and published data, and used to generate expected distributions for each species. A. flavipes is predicted to occur primarily in warm, inland areas of south- eastern Australia with a mean annual rainfall of 785 mm, but to occur along the coast in South Australia and southern Queensland. In contrast, the distributions of A. stuartii and A. agilis are predicted to be broadly coastal, with the former occurring in northern New South Wales and southern Queensland in areas with high mean annual rainfall (1430 mm) and temperature (16.0°C), the latter in southern New South Wales and Victoria in cooler areas (11.8°C annual mean) with intermediate rainfall (1071 mm). Sympatry appears to be limited between A. flavipes and its two congeners; A. stuartii and A. agilis are predicted to be parapatric with only two small areas of overlap being evident.

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