Palaeoecological evidence for sustained change in a shallow Murray River (Australia) floodplain lake: regime shift or press response
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Date
2017-02-01
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Springer Link
Abstract
Paleolimnological techniques can reveal long-term perturbations and associated stable state transitions of lake ecosystems. However, such transitions are difficult to predict since changes to lake ecosystems can be abrupt or gradual. This study examined whether there were past transitions in the ecological regime of Kings Billabong, a shallow River Murray wetland in southeast Australia. A 94-cm-long core, covering c. 90 years of age, was analysed at 1 cm resolution for subfossil cladocerans, diatoms and other proxies. Prior to river regulation (c. 1930), the littoral to planktonic ratios of cladocerans and diatoms, and bulk sediment δ13C values were high, while the period from c. 1930 to c. 1970 experienced considerable changes to the wetland ecosystem. The abrupt nature of changes of planktonic cladocerans and diatoms, particularly after the onset of river regulation (1930s), was triggered by inundation, high rates of sedimentation and shifts in bulk sediment δ15N values. However, the transition of a once littoral-dominated community, to one favouring an increasingly turbid, plankton-dominated trophic condition following river regulation was relatively slow and lasted for decades. The progression to a new regime was likely delayed by the partial recovery of submerged plant communities and related internal dynamics.© 2016, Springer International Publishing Switzerland.
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Rivers, Sustainable development, Floods, Lakes, Isotopes, Wetlands
Citation
Kattel, G., Gell, P., zawadzki, A., & Barry, L. A. (2017). Palaeoecological evidence for sustained change in a shallow Murray River (Australia) floodplain lake: regime shift or press response?. Hydrobiologia, 787, 269-290. doi:10.1007/s10750-016-2970-9