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The feral Goat ( Capra hircus) has successfully exploited a range of landscapes around the world with occurrences of overabundance resulting in significant damage to ecological values. In forested ecosystems in Australia, there are currently limited means to control the species when compared to the range of management techniques available for other pest animals. To redress this deficiency, we designed a feed structure combined with commercially available salt blocks to attract goats to set locations in a forested study area. Structures that exploited differences in the pedal morphology (foot size and shape) of native herbivores (kangaroos and wallabies) and ungulates (feral goats and deer) were found to be highly target-specific, with feral goats freely able to access salt blocks, whilst nontarget native species were effectively excluded. Other introduced ungulate species, Fallow Deer ( Dama dama) and Red Deer ( Cervus elaphus), successfully accessed salt blocks in feed structures but at a considerably lower rate than feral goats. The capacity to present a range of bait types within a target-specific feed structure, once matched with a humane toxicant, could provide land managers with an additional cost-effective lethal control tool for future management of feral ungulates, particularly goats. [ABSTRACT FROM AUTHOR]

Abstract: Feral goats (Capra hircus) are ubiquitous across much of Australia''s arid and semi-arid rangelands, where they compete with domestic stock, contribute to grazing pressure on fragile ecosystems, and have been implicated in the decline of several native marsupial herbivores. Understanding the success of feral goats in Australia may provide insights into management strategies for this and other invasive herbivores. It has been suggested that frugal use of energy and water contributes to the success of feral goats in Australia, but data on the energy and water use of free-ranging animals are lacking. We measured the field metabolic rate and water turnover rate of pregnant and non-pregnant feral goats in an Australian rangeland during late summer (dry season). Field metabolic rate of pregnant goats (601±37kJkg−0.73 d−1) was 1.3 times that of non-pregnant goats (456±24kJkg−0.73 d−1). The water turnover rate of pregnant goats (228±18mLkg−0.79 d−1) was also 1.3 times that of non-pregnant goats (173±18kg−0.79 d−1), but the difference was not significant (P =0.07). There was no significant difference in estimated dry matter digestibility between pregnant and non-pregnant goats (mean ca. 58%), blood or urine osmolality, or urine electrolyte concentrations, indicating they were probably eating similar diets and were able to maintain osmohomeostasis. Overall, the metabolic and hygric physiology of non-pregnant goats conformed statistically to the predictions for non-marine, non-reproductive placental mammals according to both conventional and phylogenetically independent analyses. That was despite the field metabolic rate and estimated dry matter intake of non-pregnant goats being only 60% of the predicted level. We suggest that general allometric analyses predict the range of adaptive possibilities for mammals, but that specific adaptations, as present in goats, result in ecologically significant departures from the average allometric curve. In the case of goats in the arid Australian rangelands, predictions from the allometric regression would overestimate their grazing pressure by about 40% with implications for the predicted impact on their local ecology. [Copyright &y& Elsevier]

1. Many species of wildlife are harvested for sale but there are few time-series analyses of the factors determining the number of animals harvested. Economic theory predicts that price paid per animal is likely to be an important determinant of the harvest, but prices paid for alternative activities could reduce the harvest, and environmental factors such as rainfall could either constrain or enhance the harvest. 2. About 1 million feral goats Capra hircus L. are commercially harvested annually in the semi-arid rangelands of Australia, and there is much interest in how the harvest can be maximized so that the environmental impacts of the goats are minimized. 3. We developed 27 candidate models to explain monthly variation in the numbers of feral goats commercially harvested in Western Australia during July 1988 to June 2003. We fitted linear AR(1) models to the first 89 months of data and used Akaike's Information Criterion corrected for small sample size to identify the model(s) with substantial support. We then evaluated how much variation in the latter 88 months of the time series each model explained. 4. Almost 2·9 million feral goats were harvested in the study period. The two models with substantial support accounted for 70·5% and 70·6% of variation in the number of feral goats harvested during the first 89 months and 64·6% and 66·7% of variation in the subsequent 88 months. The models both included month of harvest and negative effects of rainfall in both the month of harvest and the previous month. One of the models also included a strong positive effect of the Australian Consumer Price Index-adjusted average price paid per feral goat on the number of feral goats harvested, and this model had the most support when fitted to the entire time series. 5. Synthesis and applications. This is the first study to demonstrate how both an environmental factor (rainfall) and an economic factor (average price paid per animal) can influence the size of a commercial wildlife harvest. Whilst managers can seldom modify environmental factors, our results suggest that the size of a wildlife harvest can be manipulated by altering the economics of the harvest. [ABSTRACT FROM AUTHOR]