Poisoning for production: how effective is fox baiting in south‐eastern Australia?

• 1 The European red fox Vulpes vulpes represents a continuing threat to both livestock and native vertebrates in Australia, and is commonly managed by setting ground‐level baits impregnated with 1080 (sodium fluoroacetate) poison. However, the long‐term effectiveness of such control campaigns is likely to be limited due to the ability of foxes to disperse over considerable distances and to swiftly recolonize areas from where they had been removed.
• 2 To investigate the effectiveness of fox baiting in a production landscape, we assessed the potential for foxes to reinvade baited farm property areas within the jurisdiction of the Molong Rural Lands Protection Board (RLPB), an area of 815 000 ha on the central tablelands of New South Wales, Australia. The spatial distribution and timing of fox baiting campaigns between 1998 and 2002 was estimated from RLPB records and mapped using Geographical Information System software. The effectiveness of the control campaign was assessed on the basis of the likely immigration of foxes from non‐baited farms using immigration distances calculated from published relationships between dispersal distance and home range size.
• 3 Few landholders undertook baiting campaigns in any given year, and the area baited was always so small that no baited property would have been sufficiently far from an unbaited property to have been immune from immigrating individuals. It is likely, therefore, that immigration onto farms negated any long‐term effects of baiting operations. This study highlights some of the key deficiencies in current baiting practices in south‐eastern Australia and suggests that pest management programmes should be monitored using such methods to ensure they achieve their goals.

     

The impacts and management of foxes Vulpes vulpes in Australia

• 1 The successful introduction of the red fox Vulpes vulpes into Australia in the 1870s has had dramatic and deleterious impacts on both native fauna and agricultural production. Historical accounts detail how the arrival of foxes in many areas coincided with the local demise of native fauna. Recent analyses suggest that native fauna can be successfully reintroduced to their former ranges only if foxes have been controlled, and several replicated removal experiments have confirmed that foxes are the major agents of extirpation of native fauna. Predation is the primary cause of losses, but competition and transmission of disease may be important for some species.
• 2 In agricultural landscapes, fox predation on lambs can cause losses of 1–30%; variation is due to flock size, health and management, as well as differences in the timing and duration of lambing and the density of foxes.
• 3 Fox control measures include trapping, shooting, den fumigation and exclusion fencing; baiting using the toxin 1080 is the most commonly employed method. Depending on the baiting strategy, habitat and area covered, baiting can reduce fox activity by 50–97%. We review patterns of baiting in a large sheep‐grazing region in central New South Wales, and propose guidelines to increase landholder awareness of baiting strategies, to concentrate and coordinate bait use, and to maximize the cost‐effectiveness of baiting programs.
• 4 The variable reduction in fox density within the baited area, together with the ability of the fox to recolonize rapidly, suggest that current baiting practices in eastern Australia are often ineffective, and that reforms are required. These might include increasing landholder awareness and involvement in group control programs, and the use of more efficient broadscale techniques, such as aerial baiting.

     

QUININE HYDROCHLORIDE ACCEPTABILITY AFTER WATER DEPRIVATION IN GALLUS DOMESTICUS

The latency to peck and show the oral aversion response wasmeasured when 6 Brown Leghorn hens were presented with eitherwater or 0.005 M quinine hydrochloride (QHCl) after either 2,4 or 6 h water deprivation. The absence of any differences inthe latencies to peck at water with the 3 deprivation schedulesindicated no significant increase in the level of motivation,whereas, it was found that the latencies to peck at the quininesolution were significantly reduced with increasing deprivation.After 2 h deprivation the birds showed significantly longerlatencies than with water but after 6 h deprivation there wasno significant difference. By comparing the ratio values ofthe number of pecks followed by the oral aversion response dividedby the total number of pecks given to the QHCl solution it wasfound that there was a significant decrease in this ratio from2 to 6 h deprivation. It was suggested that the increase inacceptance of the quinine hydrochloride following deprivationmay be due to changes in ‘taste’ sensitivity.     

Lantana camara L. invasions in dry rainforest - open forest ecotones: The role of disturbances associated with fire and cattle grazing

Abstract A field experiment was used to evaluate the effects of fire and cattle grazing on the initiation of Lantana camara invasions in dry rainforest-open forest ecotones in the gorges of the Macleay River, NSW. A factorial combination of four factors (burning, biomass removal, soil scarification, and fertilization) at two levels (presence and absence) was established to assess the suitability of disturbed patches for germination, survival, and growth in association with changes in microclimate and resource availability. Burning, biomass removal and soil scarification, either singularly or in any combination, significantly increased germination, on average, by 19%, from 50.2% to 59.7%. Survival increased on average 26% across all treatments while mortality decreased by 26% when compared with the control. The differences between treatment combinations were not significant. Seedling growth was significantly enhanced by all disturbances, except by soil scarification alone. Treatment combinations that reduced vegetation cover (burning and/or biomass removal) and, therefore reduced shading, significantly increased L. camara biomass production by an average of 140% for all treatments. The control yielded 14.0 g m^?2, while fertilizer alone and biomass removal alone yielded 27.6 g m^?2 and 40.5 g m^?2, respectively. Other treatment combinations averaged 35.2 g m^?2 and were not significantly different from each other. Consequently, successful invasions are likely to occur whenever canopy disturbances create patches of greatly decreased competition and/or increased resource availability. Shading plays a greater role as a limiting factor than any other, while surface soil macronutrient levels are also important, particularly when combined with canopy disturbances that increase light availability. The effects of biomass reduction and soil disturbance associated with fire and cattle grazing are significant in the successful invasion of L. camara. Management strategies to reduce weed encroachment and community degradation must identify and maintain ecological barriers to L. camara invasion in order to promote rainforest conservation and biodiversity.