The role of substrate type on benthic diatom assemblages in the Daly and Roper Rivers of the Australian wet-dry tropics

S. A. Townsend and P. A. Gell
Hydrobiologia, 548, 1, 101-115, 2005-10
The selection of one or more river substrata for the collection of benthic diatoms is fundamental to any monitoring or research programme. In the wet/dry tropics of Australia, where the use of benthic diatoms for river health assessment is in its infancy, the comparability of diatom assemblages on river substrata has been assessed. Benthic diatoms were sampled from seven river sites, with a range of ionic chemistries but low nutrient concentrations. A total of 198 taxa were identified, with some taxa common to temperate Australia. Common species were found on all substrata, with sometimes statistically significantly different relative abundances. The principal finding was the similarity of the epilithon and epidendron, which are considered to be indistinguishable. Rock and wood hard substrata can be substituted for one another during field surveys, thereby increasing the number of potential sample sites available for monitoring activities that standardise to a hard substrate.

A. J. Bruce
Hydrobiologia, 231, 2, 131-139, March 1992
In a recent review of the Australian species of the freshwater shrimp genus Macrobrachium, an identification key did not include M. handschini (Roux), a little known species first recorded from the Katherine River NT and not subsequently reported. Roux's original description was brief and unillustrated and was inadequate for accurate systematic assessment. In this paper an illustrated redescription is provided of the type specimens from Katherine River.

Environmental Water Requirements of Vallisneria nana in the Daly River, Northern Territory

N. Rea, P. Dostine, P. Cook, I. Webster and D. Williams
Department of Infrastructure, Planning and Environment, Repo2t 35/2002

This project focuses on the major riverine plant, Vallisneria nana R.Br., beds of which are a keystone habitat. Macrophytes play a role in providing food, breeding sites and refuge for animals, and in the cycling of nutrients, metals and carbon. They slow currents, trap organic matter, sediments and nutrients, reduce turbidity, stabilise banks, increase shade and reduce water temperatures. Vallisneria species were once considerably abundant in the regulated inland rivers of south-eastern Australia. Their loss is attributed to adverse changes in water quality and flow. The loss of V. nana would cause a cascade of adverse changes across the food web. The overall project objective was to make recommendations about the environmental conditions needed to sustain V. nana and its functional role in the Daly River.

Effects of habitat fragmentation on the vertebrate fauna of tropical woodlands, Northern Territory

B. R. Rankmore and O. F. Price
in Conservation of Australia's Forest Fauna, 2nd ed. Royal Zoological Society of New South Wales, 2004
Fauna surveys were conducted in cleared areas, remnants of eucalyptus woodlands of various size and degree of isolation, and undisturbed 'continuous' woodland at Litchfield NT and Tipperary NT to determine the effects of clearing and habitat fragmentation on vertebrate fauna populations and distributions. The surveys identified 75 species of birds, mammals, frogs and reptiles of sufficient frequency to analyse. Only 25% of the species used modified land, but most (69%) were recorded in corridors. No species could be confidently classified as an edge specialist. The area or size of remnant vegetation, the total amount of woodland within a four km radius of the fragment, and connectivity all had a strong positive influence on animals occurring within a fragment. Fire regimes and density of trees also had an important influence on animals in remnant woodlands.

Draft conservation plan for the Daly Basin bioregion

Department of Infrastructure, Planning and Environment,

This draft plan is concerned with ensuring the protection of conservation values, such as providing breeding area, habitat and refuge for important wildlife populations, especially of fish, turtles, insects, waterbirds and crocodiles. The goal of this conservation plan is to ensure that the species, ecosystems and ecological processes present in the Daly Basin are adequately conserved.

This plan discusses the features of the Daly Basin bioregion; geology, soils, water, flora, fauna and the history of human occupation. The key threatening processes in the basin and the proposed mitigation measures are also detailed.

The informative conservation draft plan provides information on a large range of conservation issues within the study basin bioregion, also provided in the plan are control measures that have already been established and suggestions to further developing them.

Movement, activity patterns and habitat use of feral pigs (Sus scrofa) in a tropical habitat

P. Caley
Wildlife Research, 24, 77-87,

River foodwebs: bottom up and top down control of tropical river food webs

M. Douglas
Using experiments researchers will identify the sources of organic matter underpinning tropical river foodwebs, factors controlling plant growth in tropical rivers and which consumers (animals) exert the most influence on the ecosystem. Work, commencing in the Daly river, will build on previous research activity.
http://www.track.gov.au/research.html

Environmental flows and ecological assets: flow-ecology relationships for biodiversity and ecosystem processes

P. Davies
This research will investigate the relationships between flow and fish, habitats, foodwebs and ecosystem processes in tropical rivers. It will build on work already done as part of the "Daly river fish and environmental flows" project. The project will develop models and tools which evaluate the environmental consequences of flow alteration.
http://www.track.gov.au/research.html

Inventory and risk assessment of water dependent ecosystems in the Daly basin, Northern Territory, Australia

G. W. Begg, R. A. van Dam, J. B. Lowry, C. M. Finlayson and D. J. Walden
Supervising Scientist, 2001
The specific aims of this inventory and risk assessment were to map and store in a Geographical Information System (GIS) the area, location and extent of a range of water dependent ecosystems in the Daly basin; establish threats to these ecosystems from forecast and existing water use and land management practices and overlay this information on the GIS-based map; identify which ecosystems are most at risk and where possible provide an assessment of the extent of this risk; and provide a mapping-base describing habitats critical for other key indicator species being investigated in the Daly basin.
http://www.environment.gov.au/ssd/publications/ssr/162.html