Managing wetlands as off-river storages: impacts on zooplankton communities
- 435 Downloads
The competing demands of the environment and agriculture has challenged managers of waterways and prompted the development of new and novel ways of providing water for consumptive use without compromising the aquatic ecosystem. One partial remedy that has been proposed involves using wetlands as intermediary off-river storages to achieve consumptive benefits whilst maintaining ecological values. This study assessed the suitability of such a strategy by examining the impact of artificial drawdown on wetland zooplankton communities. An experiment was undertaken in outdoor mesocosms in which two treatments were compared over a 109-day duration: (1) partial artificial drawdown—where approximately half of the water was siphoned out after 42 days; and (2) natural drawdown—where the water was left to drawdown naturally via evaporation. Artificial drawdown only caused a small acceleration (<4 weeks) in the decline of abundance and density associated with natural population fluctuations, and temporarily changed the community structure. Furthermore, it had no effect on taxon richness, community composition and the initiation of dormancy. This suggests that wetlands could potentially be used for supporting consumptive demands whilst still maintaining abundant and diverse zooplankton communities, and hence a suitable food supply for higher order consumers such as fish and waterfowl.
KeywordsRiver regulation Water sharing Dormancy Drawdown
The authors wish to thank Catherine McInerney, Rochelle Petrie, Matthew Vogel, Danielle Smith and Simon Maffei for assistance with setting up the mesocosms, sampling and sample processing. We also thank The University of Melbourne, Dookie Campus, for their support in obtaining the sediment used in the mesocosms, and Wonga Wetlands, Albury, for the use of their facilities during the mesocosm experiment. This project was part of the larger Farms, Rivers and Markets Project, which is an initiative of Uniwater and funded by the National Water Commission, the Victorian Water Trust, The Dookie Farms 2000 Trust (Tallis Trust) and The University of Melbourne. The Farms, Rivers and Markets Project is supported by the Departments of Sustainability and Environment and Primary Industry, the Goulburn Broken Catchment Management Authority and Goulburn-Murray Water.
- Boltovskoy, D. & H. E. Mazzoni, 1988. The effects of sampling gear and environmental conditions on the abundance estimates of freshwater zooplankton. Revue d’Hydrobiologie Tropicale 21: 21–34.Google Scholar
- Clarke, K. R. & R. M. Warwick, 2001. Change in marine communities: an approach to statistical analysis and interpretation. PRIMER-E, Plymouth.Google Scholar
- Growns, J. E. & I. O. Growns, 1996. Predicting species richness for Australasian freshwater macroinvertebrates: do we want to know? Memoirs of the Museum of Victoria 56: 223–230.Google Scholar
- ISO, 1992. Water quality – measurement of biochemical parameters – spectrometric determination of the chlorophyll-a concentration. ISO 10260, International Organization for Standardization.Google Scholar
- Johannsson, O. E., M. A. Shaw, N. D. Yan, J.-M. Filion & D. F. Malley, 1993. A comparison of freshwater zooplankton sampling gear: nets, traps and submersible pump. Canadian Technical Report of Fisheries and Aquatic Sciences 1894: 1–29.Google Scholar
- Shiel, R. J., 1995. A guide to the identification of rotifers, cladocerans and copepods from Australian inland waters. Co-operative Research Centre for Freshwater Ecology/The Murray-Darling Freshwater Research Centre, Albury.Google Scholar
- Western, A., B. Gawne, N. Bond, J. Costelloe, K. Dassanayake, B. Farquharson, B. George, R. MacNally, D. Nielsen, N. Ning, T. Ramilan, M. Sammonds, W. Shenton, M. Stewardson & G. Vietz, 2011. Farms, Rivers & Markets Project. Milestone 6 Discussion Paper: Rivers, Groundwater and Environmental Targets.Google Scholar