Register      Login
Marine and Freshwater Research Marine and Freshwater Research Society
Advances in the aquatic sciences
REVIEW

River and wetland food webs in Australia’s wet–dry tropics: general principles and implications for management

Michael M. Douglas A D , Stuart E. Bunn B and Peter M. Davies C
+ Author Affiliations
- Author Affiliations

A Tropical Wetlands Program, Charles Darwin University, Darwin, NT 0909, Australia.

B Centre for Riverine Landscapes, Griffith University, Nathan, Qld 4111, Australia.

C Centre of Excellence in Natural Resource Management, The University of Western Australia, Albany, WA 6330, Australia.

D Corresponding author. Email: michael.douglas@cdu.edu.au

Marine and Freshwater Research 56(3) 329-342 https://doi.org/10.1071/MF04084
Submitted: 22 November 2004  Accepted: 2 March 2005   Published: 3 June 2005

Abstract

The tropical rivers of northern Australia have received international and national recognition for their high ecological and cultural values. Unlike many tropical systems elsewhere in the world and their temperate Australian counterparts, they have largely unmodified flow regimes and are comparatively free from the impacts associated with intensive land use. However, there is growing demand for agricultural development and existing pressures, such as invasive plants and feral animals, threaten their ecological integrity. Using the international literature to provide a conceptual framework and drawing on limited published and unpublished data on rivers in northern Australia, we have derived five general principles about food webs and related ecosystem processes that both characterise tropical rivers of northern Australia and have important implications for their management. These are: (1) the seasonal hydrology is a strong driver of ecosystem processes and food-web structure; (2) hydrological connectivity is largely intact and underpins important terrestrial–aquatic food-web subsidies; (3) river and wetland food webs are strongly dependent on algal production; (4) a few common macroconsumer species have a strong influence on benthic food webs; and (5) omnivory is widespread and food chains are short. The implications of these ecosystem attributes for the management and protection of tropical rivers and wetlands of northern Australian are discussed in relation to known threats. These principles provide a framework for the formation of testable hypotheses in future research programmes.

Extra keywords: connectivity, floodplain, flood pulse, omnivory, primary production, stable isotopes.


Acknowledgments

Much of the authors’ research referred to in this review was supported by Land and Water Australia, Environment Australia and the Water and Rivers Commission (particularly Kerry Trayler and Roy Stone). Susan Creagh, Andrew Storey, Ruth O’Connor and Michelle Winning are thanked for their assistance with the collection and analysis of stable isotope data. This review was prepared with support from the Land and Water Australia Tropical Rivers Program. This manuscript was improved by suggestions from Craig Layman and two anonymous reviewers.


References

Abramovitz J. N. (1996). Imperilled waters, impoverished future: the decline of freshwater ecosystems. Worldwatch paper 128. Worldwatch Institute, Washington, DC.

Australian Tropical Rivers Group (2004). ‘Securing the North: Australia’s Tropical Rivers. A Statement by the Australian Tropical Rivers Group.’ (WWF Australia: Sydney.) http://www.wwf.org.au/, verified April 2005.

Bayley, P. B. (1988). Factors affecting growth rates of young tropical floodplain fishes: seasonality and density-dependence. Environmental Biology of Fishes 21, 127–142.
Bishop K. (1983). Feeding habits of freshwater fishes of the Alligator Rivers Region. In ‘Proceedings of the Scientific Workshop on Environmental Protection in the Alligator Rivers Region, Northern Territory, 17–20 May 1983, Vol. 2, paper 47’. Office of the Supervising Scientist for the Alligator Rivers Region, Sydney.

Bishop K. A., and Forbes M. A. (1991). The freshwater fishes of northern Australia. In ‘Monsoonal Australia: Landscape Ecology and Man in the Northern Lowlands’. (Eds C. D. Haynes, M. G. Ridpath, M. A. J. Williams and A. A. Balkema.) pp. 79–107. (Brookfield: Rotterdam.)

Bishop, K. A. , Pidgeon, R. W. J. , and Walden, D. J. (1995). Studies on fish movement dynamics in a tropical floodplain river – prerequisites for a procedure to monitor the impacts of mining. Australian Journal of Ecology 20, 81–107.
Bunn S. E., Storey A. W., and Tenakenai C. (1999b). Energy sources supporting Fly River fish communities. Unpublished report to Ok Tedi Mining Ltd. http://www.oktedi.com/reports/, verified April 2005.

Bunn, S. E. , Davies, P. M. , and Winning, M. (2003). Sources of organic carbon supporting the food web of an arid zone floodplain river. Freshwater Biology 48, 619–635.
Crossref | GoogleScholarGoogle Scholar | Cohen J. E., Briand F., and Newman C. M. (1990). ‘Community Food Webs: Data and Theory.’ (Springer-Verlag: New York.)

Crowl, T. A. , McDowell, W. H. , Covich, A. P. , and Johnson, S. L. (2001). Freshwater shrimp effects on detrital processing and nutrients in a tropical headwater stream. Ecology 82, 775–783.
Douglas M. M., Townsend S. A., and Lake P. S. (2003). Streams. In ‘Fire in Tropical Savannas: The Kapalga Experiment’. (Eds A. N. Andersen, G. D. Cook and R. J. Williams.) pp. 59–78. (Springer: New York.)

Erskine W. D., Begg B. W., Jolly P., Georges A., O’Grady A., Eamus D., Rea N., Dostine P., Townsend S. A., and Padovan A. (2003). Recommended environmental water requirements for the Daly River, Northern Territory, based on ecological, hydrological and biological principles. Supervising Scientist Report 175. National River Health Program, Environmental Flows Initiative Technical Report 4. Supervising Scientist, Darwin.

Estes, J. A. , and Duggins, D. O. (1995). Sea otters and kelp forests in Alaska: generality and variation in a community ecological paradigm. Ecological Monographs 65, 75–100.
Finlayson C. M. (1988). Productivity and nutrient dynamics of seasonally inundated floodplains in the Northern Territory. In ‘Northern Australia: Progress and Prospects. Floodplains Research’. (Eds D. Wade-Marshall and P. Loveday.) pp. 58–83. (Australia National University North Australia Research Unit: Darwin.)

Finlayson, C. M. (1991). Production and major nutrient composition of three grass species on the Magela floodplain, Northern Territory, Australia. Aquatic Botany 41, 263–280.
Crossref | GoogleScholarGoogle Scholar | Finlayson C. M. (1993). Vegetation changes and biomass on an Australian monsoonal floodplain. In ‘Wetlands and Ecotones: Studies on Land–Water Interactions’. (Eds B. Gopal, A. Hillbricht-Ilkowska and R. G. Wetzel.) pp. 157–171. (International Scientific Publications: New Delhi.)

Finlayson C. M., and von Oertzen I. (1996). The Kadadu region. In ‘Landscape and Vegetation Ecology of the Kakadu Region, Northern Australia’. (Eds C. M. Finlayson and I. von Oertzen.) pp. 1–15. (Kluwer Academic Publishers: Dordrecht.)

Finlayson C. M., Bailey B. J., Freeland W. J., and Fleming M. R. (1988). Wetlands of the Northern Territory. In ‘The Conservation of Australian Wetlands’. (Eds A. J. McComb and P. S. Lake.) pp. 103–126. (Surrey Beatty and Sons: Sydney.)

Finlayson C. M., Bailey B. J., and Cowie I. D. (1990). Characteristics of a seasonally flooded freshwater system in monsoonal Australia. In ‘Wetland Ecology and Management: Case Studies’. (Eds D. F. Whigham, D. F. Good and J. Kvet.) pp. 141–162. (Kluwer Academic: Dordrecht.)

Flecker, A. S. , and Taylor, B. W. (2004). Tropical fishes as biological bulldozers: Density effects on resource heterogeneity and species diversity. Ecology 85, 2267–2278.
Gardner S., Finlayson C. M., and Pidgeon R. (2002). Description and literature review of the flora and vertebrate fauna of Magela Creek, Alligator Rivers Region, Northern Australia. Supervising Scientist, Darwin.

Goulding M. (1980). ‘The Fishes and the Forest.’ (University of California Press: Berkeley, CA.)

Goulding M. M., Carvalho L., and Ferreira E. G. (1988). ‘Rio Negro: Rich Life in Poor Water.’ (SPB Academic Publishing: The Hague.)

Gregory, S. V. , Swanson, F. J. , McKee, W. A. , and Cummins, K. W. (1991). An ecosystem perspective of riparian zones. Bioscience 41, 540–551.
Griffin R. (1995). Wetland habitats and barramundi. In ‘Wetland Research in the Wet–Dry Tropics of Australia’. Supervising Scientist Report 101. (Ed. C. M. Finlayson.) pp. 64–68. Supervising Scientist, Canberra.

Hadwen, W. L. , and Bunn, S. E. (2004). Can tourists influence the contribution of autochthonous carbon to littoral zone food webs? Marine and Freshwater Research 55, 701–708.
Crossref | GoogleScholarGoogle Scholar | Humphrey C. L., and Simpson R. D. (1985). The biology and ecology of Velesunio angasi (Bivalvia: Hydiidae) in the Magela Creek, Northern Territory (4 parts). Supervising Scientist for the Alligator Rivers Region, Canberra.

Humphrey, C. L. , Bishop, K. A. , and Brown, V. M. (1990). Use of biological monitoring in the assessment of effects of mining wastes on aquatic ecosystems of the Alligator Rivers Region, tropical Northern Australia. Environmental Monitoring and Assessment 14, 139–181.
Crossref | GoogleScholarGoogle Scholar | Humphrey C. L., Storey A. W., and Thurtell L. (2000). AUSRIVAS: Operator sample processing errors and temporal variability: implications for model sensitivity. In ‘Assessing the Biological Quality of Fresh Waters. RIVPACS and Other Techniques’. (Eds J. F. Wright, D. W. Sutcliffe and M. T. Furse.) pp. 143–163. (Freshwater Biological Association: Ambleside.)

Jenkins R. W. G., and Forbes M. A. (1985). Seasonal variation in abundance and distribution of Crocodylus porosus in the tidal East Alligator River, Northern Australia. In ‘Biology of Australasian Frogs and Reptiles’. (Eds G. Grigg, R. Shine and H. Ehmann.) pp. 63–69. (Surrey Beatty & Sons Pty Ltd: Chipping Norton, NSW.)

Jepsen, D. B. , and Winemiller, K. O. (2002). Structure of tropical river food webs revealed by stable isotope ratios. Oikos 96, 46–55.
Crossref | GoogleScholarGoogle Scholar | Junk W. J. (Ed.) (1997). ‘The Central Amazon Floodplain: Ecology of a Pulsing System. Ecological Studies: Analysis and Synthesis.’ (Springer-Verlag: Berlin.)

Junk W. J., and Welcomme R. L. (1990). Floodplains. In ‘Wetlands and Shallow Continental Water Bodies’. (Ed. B. C. Patten.) pp. 491–524. (SPB Academic Publishing bv: The Hague.)

Junk W. J., Bayley P. B., and Sparks R. E. (1989). The flood pulse concept in river–floodplain systems. In ‘Proceedings of the International Large Rivers Symposium’. Canadian Special Publication of Fisheries and Aquatic Sciences 106, 110–127.

Kennett, R. , and Tory, O. (1996). Diet of two freshwater turtles, Chelodina rugosa and Elseya dentata (Testudines, Chelidae) from the wet-dry tropics of northern Australia. Copeia 1996(2), 409–419.
Kent S. (2001). Top-down control in a stream community under contrasting flow regimes. Honours thesis. Northern Territory University, Darwin.

Layman C. A., Winemiller K. O., and Arrington D. A. (In pressa). Describing the structure and function of a neotropical river food web using stable isotope ratios, stomach contents, and functional experiments. In ‘Dynamic Food Webs: Multispecies Assemblages, Ecosystem Development, and Environmental Change’. (Eds J. C. Moore, P. De Ruiter and V. Wolters.) (Elsevier/Academic Press.)

Layman, C. A. , Winemiller, K. O. , Arrington, D. A. , and Jepsen, D. B. (In pressb). Body size and trophic position in a diverse tropical food web. Ecology ,
Legler J. M. (1980). Taxonomy, distribution and ecology of freshwater turtles in the Alligator Rivers Region, Northern territory. Open File Record 2. Supervising Scientist for the Alligator Rivers Region, Canberra.

Lewis, W. M. , Hamilton, S. K. , Rodriguez, M. A. , Saunders, J. F. , and Lasi, M. A. (2001). Foodweb analysis of the Orinoco floodplain based on production estimates and stable isotope data. Journal of the North American Benthological Society 20, 241–254.
Lowe-McConnell R. H. (1987). ‘Ecological Studies in Tropical Fish Communities.’ (Cambridge University Press: Cambridge, UK.)

Lynch, R. J. , Bunn, S. E. , and Catterall, C. P. (2002). Adult aquatic insects: potential contributors to riparian food webs in Australia’s wet-dry tropics. Austral Ecology 27, 515–526.
Crossref | GoogleScholarGoogle Scholar | McComb A. J., Atkins P. R., Birch P. B., Gordon D. M., and Lukatelich R. J. (1995). The Peel–Harvey estuarine system, Western Australia. In ‘Eutrophic Shallow Estuaries and Lagoons’. (Ed. A. J. McComb.) pp. 5–17. (CRC Press: London.)

McMahon T. A., Finlayson B. L., Haines A. T., and Srikanthan R. (1991). ‘Global Runoff: Continental Comparisons of Annual Flow and Peak Discharges.’ (Catena Verlag: Cremlingen, Germany.)

Minagawa, M. , and Wada, F. (1984). Stepwise enrichment of δ15N along food chains: further evidence and the relation between δ15N and animal age. Geochimica et Cosmochimica Acta 48, 1135–1140.
Crossref | GoogleScholarGoogle Scholar | Morton S. R., and Brennan K. G. (1991). Birds. In ‘Monsoonal Australia Landscape, Ecology and Man in the Northern Lowlands’. (Eds C. D. Haynes, M. G. Ridpath and M. A. J. Williams.) pp. 133–151. (A. A. Balkema: Rotterdam.)

NGIS (2004). ‘Australia’s Tropical Rivers – Data Audit.’ (Land and Water Australia: Canberra.)

NLWRA (2002). ‘Australian Catchment, River and Estuary Assessment 2002 – Volume 1.’ (Land and Water Australia: Canberra.)

Outridge, P. M. (1988). Seasonal and spatial variations in benthic macroinvertebrate communities of Magela Creek, Northern Territory. Australian Journal of Marine and Freshwater Research 39, 211–223.
Pidgeon R. W. J., and Boyden J. (1993). Fish migration data collected during 1991/92 wet season. Supervising Scientist for the Alligator Rivers Region, Canberra.

Pimm S. L. (1982). ‘Food Webs.’ (Chapman and Hall Ltd: London.)

Polis, G. A. (1999). Why are parts of the world green? Multiple factors control productivity and the distribution of biomass. Oikos 86, 3–15.
Postel S., and Richter B. (2003). ‘Rivers for Life: Managing Water for People and Nature.’ (Island Press: Washington, DC.)

Power, M. E. , Sun, A. , Parker, G. , Dietrich, W. E. , and Wootoon, J. T. (1995b). Hydraulic food-chain models: an approach to the study of food-web dynamics in large rivers. Bioscience 45, 159–166.
Rea N., Dostine P., Cook S., Webster I., and Williams D. (2002). Environmental water requirements of Vallisneria nana in the Daly River, Northern Territory. Final milestone report for project ID 23087. Northern Territory Department of Infrastructure Planning and Environment, Darwin.

Redhead, T. D. (1979). On the demography of Rattus sordidus colletti in monsoonal Australia. Australian Journal of Ecology 4, 115–136.
Sharley A. J., and Malipatil M. B. (1986). Aquatic insect emergence from waterbodies in the vicinity of Ranger uranium mine, Jabiru, Northern Territory. Open file record 48. Supervising Scientist for the Alligator Rivers Region, Canberra.

Shine R. (1986). Diets and abundance of aquatic and semi-aquatic reptiles in the Alligator Rivers Region. Supervising Scientist for the Alligator Rivers Region, Canberra.

Shine, R. , and Lambeck, R. (1985). A radiotelemetric study of movements, thermoregulation and habitat utilisation of Arafura filesnakes (Serpentes: Acrochordidae). Herpetologia 41, 351–361.
SoE (1996). Australia – State of the Environment Report 1996. Department of Environment Sport and Territories, Canberra.

Storey A. W., and Smith R. E. W. (1998). Food webs for the Fly River fish fauna. Unpublished report to Ok Tedi Research & Management and R&D Environmental Pty Ltd. http://www.oktedi.com/reports/, verified April 2005.

Storrs M. J., and Finlayson C. M. (1997). A review of wetland conservation issues in the Northern Territory. Supervising Scientist, Darwin.

Strayer, D. L. , Hattala, K. A. , and Kahnle, A. W. (2004). Effects of an invasive bivalve (Dreissena polymorpha) on fish in the Hudson River estuary. Canadian Journal of Fisheries and Aquatic Sciences 61, 924–941.
Crossref | GoogleScholarGoogle Scholar | Walker T. D., and Tyler P. A. (1983). Primary productivity of phytoplankton in billabongs of the Alligator Rivers Region. Open file record 8. Supervising Scientist for the Alligator Rivers Region, Canberra.

Wantzen, K. M. , Machado, F. D. , Voss, M. , Boriss, H. , and Junk, W. J. (2002). Seasonal isotopic shifts in fish of the Pantanal wetland, Brazil. Aquatic Sciences 64, 239–251.
Winemiller K. O. (1996). Dynamic diversity: fish communities of tropical rivers. In ‘Long-term Studies of Vertebrate Communities’. (Eds M. L. Cody and J. A. Smallwood.) pp. 99–134. (Academic Press: Orlando, FL.)

Winemiller K. O. (2004). Floodplain river food webs: generalizations and implications for fisheries management. In ‘Proceedings of the Second International Symposium on the Management of Large Rivers for Fisheries: Sustaining Livelihoods and Biodiversity in the New Millenium, Volume 1’. (Eds R. L. Welcomme and T. Petr.) pp. 285–309. (Food and Agriculture Organization of the United Nations and Mekong River Commission: Rome.)

Winemiller, K. O. , and Jepsen, D. B. (1998). Effects of seasonality and fish movement on tropical river food webs. Journal of Fish Biology 53, 267–296.
Wirf L. (2003). Spatial variation in top-down control in an Australian tropical stream. Honours thesis. Charles Darwin University, Darwin.

Wootton, J. T. , and Oemke, M. P. (1992). Latitudinal differences in fish community trophic structure, and the role of fish herbivory in a Costa Rican stream. Environmental Biology of Fishes 35, 311–319.


Wurm, P. A. S. (1998). A surplus of seeds: high rates of post-dispersal seed predation in a flooded grassland in monsoonal Australia. Australian Journal of Ecology 23, 385–392.