Hurstville Grove, Australia
Hurstville Grove, Australia

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Letnic M.,University of New South Wales | Laffan S.W.,University of New South Wales | Greenville A.C.,University of Sydney | Russell B.G.,Pest and Ecological Management Unit | And 3 more authors.
Biodiversity and Conservation | Year: 2014

The spatial configuration of landscapes can be an important factor influencing the dispersal, distribution and abundance of invasive animals and consequently their impacts. In arid landscapes worldwide, humans have increased the availability of surface water by creating artificial water points (AWP) for livestock and wildlife viewing. The resource subsidy provided by AWP can influence the functioning of arid ecosystems by affecting the density, distribution and activity of water-dependent native and invasive animals and thus facilitate their trophic and competitive interactions. In this study, we used dung count indices to investigate the activity of an invasive herbivore, feral goats (Capra hircus), and native herbivores (kangaroos, Macropus spp.) in relation to surface water and habitat type in three conservation reserves located in arid Australia. Activity of feral goats showed a strong preference for rocky ranges habitat and decreased with distance from water. Kangaroo activity showed a strong preference for mulga woodlands, but was independent of distance from water. Our results suggest that artificial water points may exacerbate the impacts of feral goats by functioning as focal points for their activity. Restricting goats’ access to water by closure of water points or strategic fencing, such that the mean distance to water across the landscape is increased, may be an effective strategy to reduce goat grazing impacts in conservation reserves where natural sources of water are scarce but is unlikely to affect the grazing patterns of kangaroos. Our study suggests that there is scope to control populations of water-dependent invasive vertebrates in arid regions by restricting their access to artificial water points. © 2014, Springer Science+Business Media Dordrecht.

Hamilton M.A.,Pest and Ecological Management Unit | Winkler M.A.,Pest and Ecological Management Unit | Cherry H.,Pest and Ecological Management Unit | Downey P.O.,Pest and Ecological Management Unit | Downey P.O.,University of Canberra
Plant Protection Quarterly | Year: 2012

Bitou bush (Chrysanthemoides monilifera subsp. rotundata (DC.) T.Norl.) is a South African shrub that has invaded large areas of coastal south-eastern Australia. It is widespread along the coast, where it negatively impacts native plants and ecological communities. Detailed spatial information is critical for making informed management decisions, particularly to assist in setting on-ground priorities and allocating resources, and to evaluate the effectiveness of weed management. The distribution of bitou bush was mapped previously in New South Wales; this paper presents an updated assessment of the distribution and density of bitou bush in Australia for 2008. The data were collated from a range of land managers and community groups, and analysed to determine area, density and spatial changes in bitou bush distribution. Mapping data were also analysed with respect to conservation areas in New South Wales, and national bitou bush containment lines, established to prevent northern and southern spread. The total area of bitou bush in Australia increased by 20% since 2001; 83% of the increase consisted of infestations with less than 10% cover. However, this spread has been offset by a 43% reduction in infestations with greater than 40% cover. Some of the overall increase in area may be attributed to a more comprehensive survey methodology, as this study may have captured sparse infestations that were not recorded in previous surveys. The distribution of bitou bush was found to be highly coastal, with 90.3% of bitou bush within 2.5 km of the coastline. The area of bitou bush in conservation areas in New South Wales decreased by 21%, including a 56% decrease in infestations with greater than 40% cover. Management in national containment zones has successfully restricted bitou bush Changes in the distribution and density of bitou bush (Chrysanthemoides monilifera subsp. rotundata (DC.) T.Norl.) in eastern Australia. Mark A. HamiltonA, Marion A. WinklerA,B, Hillary CherryA and Paul O. DowneyA,C A Pest and Ecological Management Unit, National Parks and Wildlife Service, Office of Environment and Heritage (New South Wales), PO Box 1967, Hurstville, NSW 1481, Australia. B Soil Science Section, Scientific Services Division, Office of Environment and Heritage (New South Wales) PO Box 3720, Parramatta, NSW 2124, Australia C Institute of Applied Ecology, University of Canberra, Australian Capital Territory 2601, Australia. spread and significantly reduced its density in these nationally significant areas. Continued support for strategic control programs will ensure the spread of bitou bush in Australia is contained.

Reynolds C.J.,University of Western Australia | Long R.L.,University of Western Australia | Flematti G.R.,University of Western Australia | Cherry H.,Pest and Ecological Management Unit | Turner S.R.,University of Western Australia
Weed Research | Year: 2014

Summary: Physiological dormancy in weed species has significant implications for weed management, as viable seeds may persist in soil seedbanks for many years. The major stimulatory compound in smoke, karrikinolide (KAR1), promotes germination in a range of physiologically dormant weed species allowing targeted eradication methods to be employed. Control of Chrysanthemoides monilifera ssp. monilifera (boneseed), a Weed of National Significance in Australia, may benefit from adopting such an approach. In this study, we hypothesised that seeds of C. monilifera ssp. monilifera exhibit physiological dormancy, germinate more rapidly as dormancy is alleviated, show fluctuations in sensitivity to KAR1 and form a persistent soil seedbank. Seeds responded to 1 μM KAR1 (40-60% germination) even during months (i.e. March, April, July, August) when seeds were observed to be more deeply dormant (control germination: 7-20%). Seeds germinated readily over a range of cooler temperatures (i.e. 10, 15, 20, 20/10 and 25/15°C) and were responsive to KAR2 (~50% germination) as well. Eradication efforts for C. monilifera ssp. monilifera may benefit from use of karrikins to achieve synchronised germination from soil seedbanks, even at times of the year when C. monilifera ssp. monilifera seeds would be less likely to germinate, allowing more rapid depletion of the soil seedbank and targeted control of young plants. © 2013 European Weed Research Society.

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