Salinity as a determinant of salt lake fauna: a question of scale

Williams, W. D.; Boulton, A. J.; Taaffe, R. G.

doi:10.1007/978-94-009-0603-7_22

Cited by 55 publications

(90 citation statements)

References 24 publications

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“…Species richness from saline lakes (3 to 100 g L-l) was not markedly lower than that of freshwater lakes, and they concluded that salinity may not be an important determinant of species occurrence over most of the salinity range occupied by the fauna of salt lakes. These findings (Williams et al, 1990) are of particular interest in the context of the calcrete aquifers which may exhibit strong salinity stratification ( Figure 39 in Watts and Humphreys, 2000) or fluctuate markedly in salinity at the surface (e.g. annual range between 5-22 g Ll; footnote Table 2 in Watts and Humphreys, 2000).…”

Section: Aquifer Characteristics Water Quality and Stratificationmentioning

confidence: 83%

Groundwater calcrete aquifers in the Australian arid zone: the context to an unfolding plethora of stygal biodiversity

Humphreys¹

2001

Rec West Aust Mus Sup

104

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-The Western Shield of Australia has been above sea level since the Palaeozoic. It is incised by ancient palaeovalieys now containing groundwater calcretes that are found throughout much of arid Australia. The calcretes are deposited, owing to surface evaporation, from a groundwater flow path that increases in salinity from fresh to hypersaline groundwater each terminating at a salt lake (playa). The calcrete aquifers contain a diverse obligate groundwater fauna (stygofauna: predominantly Crustacea) in one of the oldest non-marine landscapes on Earth. Each of the 11 calcrete areas examined so far contains a unique fauna; there are over 210 large discrete calcrete bodies in the Western Australian arid zone. This paper examines a working hypothesis that the stygofauna became isolated in the upper tributaries of the palaeodrainage systems by the progressive upstream movement of salinity from the Eocene onwards. Although each calcrete body does have a unique fauna, as predicted by the hypothesis, the hypothesis has proved too simple because the hydrochemical cycles are repeated along the length of the palaeochannels, each terminating in a saltlake immediately downflow of the calcrete. A new hypothesis has to incorporate these intervals of hypersaline groundwater / calcrete discontinuities acting as barriers to dispersal of the stygofauna. The paper focuses on the geological and landscape setting, and the hydrochemical and groundwater context in which this stygal diversity is found. It is intended to serve as a background resource for further work on this diverse stygofauna. A synopsis is provided of the knowledge of this stygofauna. The presence of such highly diverse and locally endemic stygofauna, often ancient relictual lineages, in a major economic resource within arid Australia poses delicate and chalienging conservation issues. At the same time the scientific challenge is considerable to understand the development and functioning of these systems in order that they can be managed sustainably.

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Section: Aquifer Characteristics Water Quality and Stratificationmentioning

confidence: 83%

Groundwater calcrete aquifers in the Australian arid zone: the context to an unfolding plethora of stygal biodiversity

Humphreys¹

2001

Rec West Aust Mus Sup

104

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“…Disparities between experimental data and field distributions are not uncommon (Blakeslee, 1952;Sinha, 1976;Bailey et al 1981;Williams et al 1990). However, an acknowledged limitation of this study is Coleoptera and non-culicid Diptera were not identified to species.…”

Section: Salinity Colonisation Behaviour and Insects In The Fieldmentioning

confidence: 99%

“…Other biotic and abiotic variables (such as predation, competition, microhabitat structure and stochastic encounters with water bodies) may be more influential than salinity on our measures of organism occurrence (Williams et al, 1990;Kay et al, 2001), potentially explaining differences between mesocosm and field results. Ovipositing and colonising insects are known to choose habitat that maximises survival and fitness (Spencer et al, 2002;Blaustein et al, 2004).…”

Section: Salinity Colonisation Behaviour and Insects In The Fieldmentioning

confidence: 99%

Salinity as a driver of aquatic invertebrate colonisation behaviour and distribution in the wheatbelt of Western Australia

et al. 2008

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To understand how environmental change will modify community assembly and the distribution of organisms it is valuable to understand mechanisms that drive the occurrence of organisms across the landscape. Salinisation of agricultural land in southwest Western Australia, as a result of land clearing, is a widespread environmental change, which threatens numerous taxa, but provides an opportunity to elucidate such mechanisms. Although salinisation affects terrestrial fauna and flora, the greatest impacts are seen in wetlands and waterways. Many aquatic insect taxa colonise ephemeral water bodies directly as adults or by oviposition. Few empirical studies, however, evaluate the influence of abiotic factors, such as water body salinity, on the colonisation behaviour of aquatic fauna. We conducted a manipulative experiment using mesocosms to test whether colonising insect fauna select aquatic habitats based upon salinity. We found that halosensitive fauna selected less saline mesocosms for oviposition and colonisation, demonstrating that behaviour can influence the distribution of aquatic organisms. Additionally, we utilised field surveys of insects from ephemeral water bodies across a broad region of southwest Western Australia to determine if mesocosm results reflected field observation. The abundance of the same insect taxa and taxonomic groups in the field were highly variable and, with the exceptions of Culex australicus Dobrotworksy and Drummond and Anopheles annulipes Giles (Diptera: Culicidae), did not show similar patterns of distribution to those observed in the mesocosm experiment. Both mesocosm and field assemblages exhibited similar and significant trajectories associated with the salinity gradient, even though there were differences in assemblage structure between the two. Our findings give empirical support to the importance of behaviour in the spatial distribution and assembly of some aquatic insects.

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“…At salinities below this lethal threshold, increases in salinity also depressed growth rates (Hall & Burns 2002a). In contrast, however, D. carinata has been recorded in Australian environments with salinities from 250 mg litre-1 Cl (Timms 1997) to as high as 3850 mg litre-1 Cl (Williams et al 1990). The wide range of salinity tolerances of D. carinata in Australia may reflect the genetic diversity of this species complex (Hebert 1984;Hebert & Wilson 1994 planktivorous fish in Lake Waihola consume D. carinata (Kattel 1999), and in a shallow lagoon near Lake Waihola, predation by fish appears to have contributed significantly to a midsummer decline in the abundance of D. carinata (Burns & Dodds 1999).…”

Section: Discussionmentioning

confidence: 93%

Responses of crustacean zooplankton to seasonal and tidal salinity changes in the coastal Lake Waihola, New Zealand

Hall¹,

Burns²

2003

New Zealand Journal of Marine and Freshwater Research

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Lake Waihola is a shallow, tidal, coastal lake that receives brackish inflows resulting in salinities of up to 4.8‰. We determined the importance of salinity and tidal currents on crustacean zooplankton abundance and distribution in this lake over 2 years. Tidal currents were traced using drogues, and zooplankton was sampled over tidal cycles. Tidal currents reached velocities of 35 cm s -1 closest to the tidal inlet channel. Salinity explained 26% of the variation in the abundance and species composition of the zooplankton assemblage, and accounted for >60% of the species-environment correlation. Increases in salinity resulted in a change in crustacean dominance from the freshwater calanoid copepod, Boeckella hamata Brehm, and cladoceran, Daphnia carinata King, to the estuarine copepod, Gladioferens pectinatus Brady. The abundance of D. carinata was negatively correlated with chlorophyll a concentrations, although chlorophyll a was not correlated with salinity. Future increases in salinity and tidal currents may cause significant changes in the zooplankton community structure.

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Salinity as a determinant of salt lake fauna: a question of scale

Cited by 55 publications

References 24 publications

Groundwater calcrete aquifers in the Australian arid zone: the context to an unfolding plethora of stygal biodiversity

Groundwater calcrete aquifers in the Australian arid zone: the context to an unfolding plethora of stygal biodiversity

Salinity as a driver of aquatic invertebrate colonisation behaviour and distribution in the wheatbelt of Western Australia

Responses of crustacean zooplankton to seasonal and tidal salinity changes in the coastal Lake Waihola, New Zealand

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