Gamba Grass Management in the Lower Daly

Wangamaty Landcare Co-ordinator - Joye Maddison
The Wangamaty Landcare Group and the MalakMalak rangers find and spray Gamba grass annually in the wet season and also identify & treat other grassy weeds. At the same time they to support and encourage other landholders to control and monitor their Gamba sites. The management strategy is to identify & treat ‘outliers’, follow-up at previously treated sites, survey and then tackle larger sites. Crucial to the Gamba management strategy is collecting and recording data for every site and every single outlier plant treated. This information is then passed on to DNRETAS Weed Management branch.

Wangamaty (Lower Daly River) Management Plan

ECOZ Environmental Services, (2004?)
The Wangamaty Landcare Group (WLG) initiated this study to investigate the adoption of an integrated management plan for the Lower Daly region. Recommendations include:

• implemention of a 5 year Weed Action Plan
• development of an up to date legislative framework and planning instrument to identify and rectify gaps in dealing with resource management issues
• recommendations for managing riparian zones, rainforest and wetlands
• identification of monitoring needs
• professional development with the WLG
• water allocation plan and natural resource management strategy
• pest animal study
• strategic fire management plan

Copy available for loan: NRETAS and DPI Library

Katherine Regional Weed Management Strategy 2005-2010

Department of Natural Resources,

Environment and the Arts Weed management is complex enough without trying to deal with coordination across layers of Government, land tenure and land uses in the Katherine region. This strategy will provide a common focus for all land managers and stakeholders to work towards common community issues while also addressing their own priority issues on a property, district or catchment basis through their own plans. It also provides the fundamental framework for succession planning so future land managers and government officers have a documented plan, which will provide direction and focus and prevention of “re-inventing the wheel”. The action plan will also identify gaps, which need to be addressed in the region if weed management is to be successful.
The Katherine Weed Management Strategy’s overriding purpose is to provide a healthier and more productive landscape where the impacts of weeds are minimised. The strategy is pro-active ensuring the Katherine region’s current weed status is maintained or enhanced.

Exotic grass invasion in the tropical savannah of northern Australia: ecosystem consequences

N. Rossiter, S. Setterfield, M. Douglas, L. Hutley and G. Cook
Weeds Society of New South Wales, 6-9 September 2004

Introduced African grasses are invading the tropical savannahs of northern Australia and displacing native grasses. A study aimed to quantify the effect of introduced gamba grass (Andropogon gayanus) invasion on nitrogen availability and soil water dynamics over the wet season in a tropical savannah. It was found that, compared with sites dominated by native grasses, sites invaded by gamba grass had: greatly increased fire intensities, reduced available soil nitrate levels, trebled grass water use, and more than halved deep drainage of water. Gamba grass therefore has the ability to out-compete native grasses and alter catchment hydrology to the detriment of wetlands and streams.

Inviting trouble: introduced pasture species in northern Australia

W. M. Lonsdale
Australian Journal of Ecology, 19, 345-354

Rates of spread of an invading species: Mimosa pigra in northern Australia

W. M. Lonsdale
Journal of Ecology 81, 3, 513-521, 1993

Mimosa pigra, a woody weed, has invaded the wetlands of Northern Territory. This study examined the weed's expansion and tested the assumptions and predictions of Skellam's model for aerial spread, investigated the roles of wind, flood waters and buffalo, and compared the plant's rate of increase on local and geographical scales. Skellam' s model was found to be an inadequate descriptor of spread. There was a close correlation between the increase in the area colonised by the plant and the rainfall in the previous wet season. There was no evidence for the popular perception that feral buffalo grazing suppressed the weed, nor that the removal of grazing pressure caused an upsurge in the weed. Spread behaviour on a local scale was found to be applicable on a larger scale.

Spawning site selection by feral cane toads (Bufo marinus) at an invasion front in tropical Australia

M. Hagman and R. Shine
Austral Ecology, 31, 5, 551-558, 2006-08
Spawning sites are a critical and often scarce resource for aquatic-breeding amphibians, including invasive species such as the cane toad (Bufo marinus). If toads select spawning sites based on habitat characteristics, those characteristics can be potentially manipulated to either enhance or reduce their suitability as breeding sites. A study surveyed 25 spawning sites used by cane toads, and 25 adjacent unused sites, in an area of tropical Australia recently invaded by this species. Water chemistry (pH, conductivity, salinity, turbidity) was virtually identical between the two sets of waterbodies, but habitat characteristics were very different. Toads selectively oviposited in shallow pools with gradual rather than steep slopes, and with open (unvegetated) gradually sloping muddy banks. They avoided flowing water, and pools with steep surrounds.

Indirect impacts of invasive cane toads (Bufo marinus) on nest survival in pig-nosed turtles (Carettochelys insculpta)

J. S. Doody, B. Green, R. Sims, D. Rhind, P. West and D. Steer
Wildlife Research, 33, 349-354,
http://aerg.canberra.edu.au/cgi-bin/pubs_archive.cgi?target=G

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

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

The effectiveness of hunting dogs for removing feral pigs (Sus scrofa)

P. Caley and B. Ottley
Wildlife Research, 22, 2, 147-154, 1995
A study was conducted in the Douglas Daly NT region to examine the effectiveness of a small team of hunting dogs for removing feral pigs, in relation to group size of feral pigs encountered and the population density of pigs being hunted. Hunting dogs were successful on 88% of occasions of catching or cornering solitary pigs when encountered. This rate of success rapidly declined as the group size of encountered pigs increased, with the mean maximum number of pigs that could be caught or cornered in any one encounter estimated to be about one pig per dog. One team of hunting dogs removed 22 of an estimated 79 pigs inhabiting a 94 sq km area at a rate of 0.6 pigs/h in 35 h of hunting. It was concluded that hunting with dogs is an effective way for removing residual pigs after densities have been reduced by other forms of control (A).

Engagement of Wangamaty Landcare Group in catchment management issues

Wangamaty Landcare Group
Community monitoring of water quality and pest control in Daly River catchment. Group have a number of NRM projects currently being implemented in the Lower Daly but these are not research based.