The environmental preferences of three species of Australian freshwater fish in relation to the effects of riparian degradation

Abstract

To assess the likely effects on three coexisting species of Australian freshwater fish of riparian loss, we examined the temperature, light, and habitat preferences of each species in relation to commonly documented effects of riparian degradation on stream environments. Such effects include reduced shade, instream structure, and water depth and increased temperature and invasive instream vegetation. Xiphophorus helleri, Gambusia holbrooki, and Melanotaenia duboulayi differed significantly in mean swimming depth, preferences for light and habitat, and in their patterns of behavioural change through the day. Values of interspecific spatial overlap (25-58%) indicated that the overall environmental preferences of G. holbrooki, X. helleri, and M. duboulayi were reasonably distinct. Habitat alterations associated with riparian removal are likely to favour the exotic species G. holbrooki over the native species M. duboulayi, but the results for X. helleri suggest that not all poeciliid species are strong indicators of degraded conditions.

The Effect of Shoreline Recreational Angling Activities on Aquatic and Riparian Habitat Within an Urban Environment: Implications for Conservation and Management

“…Bonferroni corrections were applied, and significant values (a = 0.013) are presented in bold indicated ecologic disturbance (e.g., presence of litter, decreased plant cover, soil compaction). Water temperature may be affected by the extent of riparian vegetation, channel geometry, and aquatic macrophytes (LeBlanc and others 1996; King and Warburton 2007). It could be reasonable to expect that decreased shoreline vegetation as well as decreased aquatic macrophyte growth in high angling-activity areas would lead to locally increased water temperatures and therefore lower dissolved oxygen levels, especially in areas of slow-moving water.…”

Behavioural interactions between the introduced plague minnow Gambusia holbrooki and the vulnerable native Australian ornate rainbowfish Rhadinocentrus ornatus, under experimental conditions

“…The results from the habitat preference experiment also support the notion that R. ornatus from sympatric populations may utilize alternative microhabitats to avoid interactions with G. holbrooki and to reduce the amount of niche overlap between the species. Allopatric populations showed very similar habitat preferences to G. holbrooki , preferring open habitats that provide maximum access to the water surface where both species forage on terrestrial insects (Casterlin & Reynolds, 1977; Arthington et al , 1983; King & Warburton, 2007). The similarity in habitat preferences between the allopatric R. ornatus populations and G. holbrooki suggests that high competitive interactions would occur following introduction.…”

“…Exotic fishes may also contribute to reducing native fish populations indirectly by altering habitat conditions and ecosystem processes, which are often exacerbated by human activities (Arthington et al , 1983). The destruction of aquatic habitats as a result of land clearance for housing development is considered to be a major factor contributing to the increase in exotic fish species in many waters around Australia (Arthington et al , 1983; King & Warburton, 2007). This is because many introduced fish species have the ability to thrive in degraded aquatic habitats and their potential effect on aquatic ecosystem structure is magnified due to their wide environmental tolerances and high densities (Kennard et al , 2005).…”

Grass-dominated stream sites exhibit low fish species diversity and dominance by guppies: an assessment of two tropical pasture river basins

“…Removal of riparian vegetation represents one of the several mechanisms that can alter the quantity and quality of these elements, resulting in grass proliferation, increased sedimentation, and depleted woody debris (Pusey & Arthington, 2003;King & Warbuton, 2007 and references therein), which leads to a less complex in-stream habitat.…”