In order to ascertain whether introduced weeds have an effect on naturally occurring aquatic fauna, this study assesses the toxicity of 3 introduced weeds that occur along the banks of rivers and ponds in New South Wales, on 4 aquatic invertebrates. Damsel Fly nymphs, Mud Eyes, Mayfly nymphs and Backswimmers were placed in petri dishes with minced leaves from either Crofton Weed, Camphor Laurel or Privet (tests), Black Wattle or Derris dust (comparisons) or no plant material (control). The toxicity of the weeds was determined by the lifespan of the invertebrates exposed to them. Damsel Fly nymphs were adversely affected by Camphor Laurel, Crofton Weed and Derris dust, but not the other treatments. Mud Eyes were most affected by Black Wattle and Crofton Weed, though results were variable and inconclusive. Mayfly larvae were most affected by Crofton Weed and Derris dust. Backswimmers were killed very quickly by all three test weeds and Derris dust. These results show differential toxic effects of the three weeds on different invertebrates, suggesting that the distribution and abundance of aquatic invertebrates may be significantly influenced by the presence of toxic weeds along the waterway. These results add to the understanding of negative impacts of bank disturbance which leads to weed infestation of stream banks.

Billyard, R. 1995. Fishcare-Our Freshwater Rivers and Streams. Fishnote, NSW Fisheries.
Bishop, K.A., Baker, L.M. and Noller, B.N. 1982. Naturally-occuring Icthyocides and a Report on Owenia vernicosa F. Muell. (Family Meliaceae), from the Magela Creek System, Northern Territory. Search 13, 150-53.
Naturally-occuring Icthyocides and a Report on Owenia vernicosa F. Muell. (Family Meliaceae), from the Magela Creek System, Northern Territory
Search
, vol. 
13
 (pg. 
150
-
53
)
CSIRO. 1991.The Insects of Australia, Vol. 1. Melbourne University Press, Melbourne.
Everhart, W.H., Eipper, A.W. and Youngs, W.D. 1976.Principles of Fishery Science. Cornell University Press, Ithaca.
Principles of Fishery Science
Harden, G.J. 1990.Flora of New South Wales. Vol. 1, UNSW Press, Sydney.
Flora of New South Wales
, vol. 
1
 
Hickin, N.E. 1964.Household Insect Pests. Hutchinson and Co., London.
Household Insect Pests
Mowatt, J. 2001. Privet. Agfact. NSW Agriculture.
Recher, H.F., Date, E.M. and Ford, H.A. 1995 The biology and management of rainforest pigeons in NSW. Species management report. No.16, NSW National Parks and Wildlife Service.
Trounce, B. and Dyason, R. 2003. Crofton Weed. Agfact. NSW Agriculture.
This content is only available as a PDF.