Alan Fletcher Research Station

Sherwood, Australia

Alan Fletcher Research Station

Sherwood, Australia
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Panetta F.D.,Alan Fletcher Research Station | Cacho O.,University of New England of Australia | Hester S.,University of New England of Australia | Sims-Chilton N.,Alan Fletcher Research Station | Brooks S.,Tropical Weeds Research Center
Journal of Applied Ecology | Year: 2011

Weed eradication efforts often must be sustained for long periods owing to the existence of persistent seed banks, among other factors. Decision makers need to consider both the amount of investment required and the period over which investment must be maintained when determining whether to commit to (or continue) an eradication programme. However, a basis for estimating eradication programme duration based on simple data has been lacking. Here, we present a stochastic dynamic model that can provide such estimates. The model is based upon the rates of progression of infestations from the active to the monitoring state (i.e. no plants detected for at least 12months), rates of reversion of infestations from monitoring to the active state and the frequency distribution of time since last detection for all infestations. Isoquants that illustrate the combinations of progression and reversion parameters corresponding to eradication within different time frames are generated. The model is applied to ongoing eradication programmes targeting branched broomrape Orobanche ramosa and chromolaena Chromolaena odorata. The minimum periods in which eradication could potentially be achieved were 22 and 23years, respectively. On the basis of programme performance until 2008, however, eradication is predicted to take considerably longer for both species (on average, 62 and 248years, respectively). Performance of the branched broomrape programme could be best improved through reducing rates of reversion to the active state; for chromolaena, boosting rates of progression to the monitoring state is more important. Synthesis and applications.Our model for estimating weed eradication programme duration, which captures critical transitions between a limited number of states, is readily applicable to any weed. A particular strength of the method lies in its minimal data requirements. These comprise estimates of maximum seed persistence and infested area, plus consistent annual records of the detection (or otherwise) of the weed in each infestation. This work provides a framework for identifying where improvements in management are needed and a basis for testing the effectiveness of alternative tactics. If adopted, our approach should help improve decision making with regard to eradication as a management strategy. © 2011 The Authors. Journal of Applied Ecology © 2011 British Ecological Society.

Skurka Darin G.M.,University of California at Davis | Schoenig S.,Integrated Pest Management Branch | Barney J.N.,University of California at Davis | Panetta F.D.,Alan Fletcher Research Station | DiTomaso J.M.,University of California at Davis
Journal of Environmental Management | Year: 2011

Large geographic areas can have numerous incipient invasive plant populations that necessitate eradication. However, resources are often deficient to address every infestation. Within the United States, weed lists (either state-level or smaller unit) generally guide the prioritization of eradication of each listed species uniformly across the focus region. This strategy has several limitations that can compromise overall effectiveness, which include spending limited resources on 1) low impact populations, 2) difficult to access populations, or 3) missing high impact populations of low priority species. Therefore, we developed a novel science-based, transparent, analytical ranking tool to prioritize weed populations, instead of species, for eradication and tested it on a group of noxious weeds in California. For outreach purposes, we named the tool WHIPPET (Weed Heuristics: Invasive Population Prioritization for Eradication Tool). Using the Analytic Hierarchy Process that included expert opinion, we developed three major criteria, four sub-criteria, and four sub-sub-criteria, taking into account both species and population characteristics. Subject matter experts weighted and scored these criteria to assess the relative impact, potential spread, and feasibility of eradication (major criteria) for 100 total populations of 19 species. Species-wide population scores indicated that conspecific populations do not necessarily group together in the final ranked output. Thus, priority lists based solely on species-level characteristics are less effective compared to a blended prioritization based on both species attributes and individual population and site parameters. WHIPPET should facilitate a more efficacious decision-making process allocating limited resources to target invasive plant infestations with the greatest predicted impacts to the region under consideration. © 2010 Elsevier Ltd.

Hester S.M.,University of New England of Australia | Brooks S.J.,Tropical Weeds Research Center | Cacho O.J.,University of New England of Australia | Panetta F.D.,Alan Fletcher Research Station
Weed Research | Year: 2010

A simulation model that combines biological, search and economic components is applied to the eradication of a Miconia calvescens infestation at El Arish in tropical Queensland, Australia. Information on the year M. calvescens was introduced to the site, the number of plants controlled and the timing of control, is used to show that currently there could be M. calvescens plants remaining undetected at the site, including some mature plants. Modelling results indicate that the eradication programme has had a significant impact on the population of M. calvescens, as shown by simulated results for uncontrolled and controlled populations. The model was also used to investigate the effect of changing search effort on the cost of and time to eradication. Control costs were found to be negligible over all levels of search effort tested. Importantly, results suggest eradication may be achieved within several decades, if resources are increased slightly from their current levels and if there is a long-term commitment to funding the eradication programme. © 2010 The Authors. Journal Compilation © 2010 European Weed Research Society.

Dane Panetta F.,Alan Fletcher Research Station | Csurhes S.,Invasive Plants and Animals | Markula A.,Invasive Plants and Animals | Hannan-Jones M.,Invasive Plants and Animals
Plant Protection Quarterly | Year: 2011

The feasibility of state-wide eradication of 41 invasive plant taxa currently listed as 'Class 1 declared pests' under the Queensland Land Protection (Pest and Stock Route Management) Act 2002 was assessed using the predictive model 'WeedSearch'. Results indicated that all but one species (Alternanthera philoxeroides) could be eradicated, provided sufficient funding and labour were available. Slightly less than one quarter (24.4%) (n = 10) of Class 1 weed taxa could be eradicated for less than $100 000 per taxon. An additional 43.9% (n = 18) could be eradicated for between $100 000 and $1M per taxon. Hence, 68.3% of Class 1 weed taxa (n = 28) could be eradicated for less than $1M per taxon. Eradication of 29.3% (n = 12) is predicted to cost more than $1M per taxon. Comparison of these WeedSearch outputs with either empirical analysis or results from a previous application of the model suggests that these costs may, in fact, be underestimates. Considering the likelihood that each weed will cost the state many millions of dollars in long-term losses (e.g. losses to primary production, environmental impacts and control costs), eradication seems a wise investment. Even where predicted costs are over $1M, eradication can still offer highly favourable benefit:cost ratios. The total (cumulative) cost of eradication of all 41 weed taxa is substantial; for all taxa, the estimated cost of eradication in the first year alone is $8 618 000. This study provides important information for policy makers, who must decide where to invest public funding.

Sims-Chilton Nikki M.,Alan Fletcher Research Station | Sims-Chilton Nikki M.,University of Queensland | Dane Panetta F.,Alan Fletcher Research Station
Plant Protection Quarterly | Year: 2011

The genus name Baccharis is after the Greek bakkaris, an oil producing plant (later called 'Celtic valerian') (Parsons and Cuthbertson 1992). The species name halimifolia is derived from the Greek alimos meaning 'seas' and the Latin folium meaning 'leaf' (Parsons and Cuthbertson 1992). Baccharis halimifolia L. belongs to the family Asteraceae which is the largest family of flowering plants, comprised of over 1100 genera and 19 000 species (Zomlefer 1994). Baccharis is a large genus, comprised of over 400 species (Mahler and Waterfall 1964, Zomlefer 1994) distributed over seven geographical areas: Brazil, Andes Mountains, Andes-Patagonia, Guyanarum, south-eastern Brazil, Mexico (including western United States) and the Antilles (including the eastern United States) (Boldt 1989). In Australia, B. halimifolia is most commonly known as groundsel bush. 'Groundsel' refers to the groundsel-like flowering heads, as in plants in the Senecio genus (Parsons and Cuthbertson 1992). In its native region it is often referred to as saltbush (Stevenson 1969, Proffitt et al. 2005), groundsel tree (Altfeld and Stiling 2006), sea myrtle (Caccamise 1977, Dickens and Boldt 1985) and eastern baccharis (Adlerz 1980). © R.G. Richardson 2011.

Palmer W.A.,Alan Fletcher Research Station | Heard T.A.,CSIRO | Sheppard A.W.,CSIRO
Biological Control | Year: 2010

Considerable progress has been made towards the successful classical biological control of many of Australia's exotic weeds over the past decade. Some 43 new arthropod or pathogen agents were released in 19 projects. Effective biological control was achieved in several projects with the outstanding successes being the control of rubber vine, Cryptostegia grandiflora, and bridal creeper, Asparagus asparagoides. Significant developments also occurred in target prioritization, procedures for target and agent approval, funding, infrastructure and cooperation between agencies. Scientific developments included greater emphasis on climate matching, plant and agent phylogeny, molecular diagnostics, agent prioritization and agent evaluation. Crown Copyright © 2009.

Twigg L.E.,Vertebrate Pest Research Section | Parker R.W.,Alan Fletcher Research Station
Animal Welfare | Year: 2010

1080 (sodium fluoroacetate)-baiting programmes are an important and often the only option for reducing the impact of invasive vertebrate pests on biodiversity and agricultural production in Australia and New Zealand. These programmes are generally recognised as being target specific, and environmentally and user safe. Nevertheless, although 1080 has few recognised long-term side-effects, its potential to disrupt endocrine systems has been recently raised, and there is some conjecture regarding the humaneness of 1080 for certain target species. However, the assessment of the humaneness of any vertebrate pesticide must be commensurate with its mode of action, metabolism, target specificity, and operational use. This has not always occurred with 1080, particularly regarding these aspects, and its overall effects. The actual risk faced by non-target species during baiting operations is not accurately reflected simply by their sensitivity to 1080. 1080 is not endocrine-disrupting or carcinogenic, and because of the lag phase before signs of poisoning occur, the time from ingestion to death is not a reliable indicator of its humaneness. Moreover, functional receptors and neurological pathways are required to experience pain. However, as 1080 impairs neurological function, mainly through effects on acetylcholine and glutamate, and as this impairment includes some pain receptors, it is difficult to interpret the behaviour of affected animals, or to assess their ability to experience discomfort and pain. This has implications for assessing the merits of including ameliorative agents in 1080 baits aimed at further improving welfare outcomes. We also suggest that the assessment of the humaneness of any vertebrate pesticide should follow the ethical pest control approach, and on this basis, believe that the use of 1080 to reduce the detrimental impacts of invasive vertebrates is ethical, particularly with respect to the expectations of the wider community. © 2010 Universities Federation for Animal Welfare.

Osunkoya O.O.,Alan Fletcher Research Station | Bayliss D.,Alan Fletcher Research Station | Panetta F.D.,Alan Fletcher Research Station | Vivian-Smith G.,Alan Fletcher Research Station
Annals of Botany | Year: 2010

Background and Aims Success of invasive plant species is thought to be linked with their higher leaf carbon fixation strategy, enabling them to capture and utilize resources better than native species, and thus pre-empt and maintain space. However, these traits are not well-defined for invasive woody vines. Methods In a glass house setting, experiments were conducted to examine how leaf carbon gain strategies differ between non-indigenous invasive and native woody vines of south-eastern Australia, by investigating their biomass gain, leaf structural, nutrient and physiological traits under changing light and moisture regimes. Key ResultsLeaf construction cost (CC), calorific value and carbon: nitrogen (C: N) ratio were lower in the invasive group, while ash content, N, maximum photosynthesis, light-use efficiency, photosynthetic energy-use efficiency (PEUE) and specific leaf area (SLA) were higher in this group relative to the native group. Trait plasticity, relative growth rate (RGR), photosynthetic nitrogen-use efficiency and water-use efficiency did not differ significantly between the groups. However, across light resource, regression analyses indicated that at a common (same) leaf CC and PEUE, a higher biomass RGR resulted for the invasive group; also at a common SLA, a lower CC but higher N resulted for the invasive group. Overall, trait co-ordination (using pair-wise correlation analyses) was better in the invasive group. Ordination using 16 leaf traits indicated that the major axis of invasive-native dichotomy is primarily driven by SLA and CC (including its components and/or derivative of PEUE) and was significantly linked with RGR.Conclusions These results demonstrated that while not all measures of leaf resource traits may differ between the two groups, the higher level of trait correlation and higher revenue returned (RGR) per unit of major resource need (CC) and use (PEUE) in the invasive group is in line with their rapid spread where introduced. © The Author 2010. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved.

Shortus M.,Alan Fletcher Research Station | Dhileepan K.,Alan Fletcher Research Station
Proceedings of the Royal Society of Queensland | Year: 2011

The invasive liana cat's claw creeper, Macfadyena unguis-cati, native to tropical Central and South America, is a major environmental weed in Queensland and New South Wales (NSW). Two morphologically distinct cat's claw creeper varieties occur in Australia, a 'short-pod' variety that is widespread through Queensland and NSW and a 'long-pod' variety restricted to a few sites in southeast Queensland. In this study we report the differences in the above-ground morphological, phenological and reproductive traits between the two varieties. The 'long-pod' variety has signifi cantly larger leaves, larger pods, and larger number of seeds per pod than the 'short-pod' variety. The 'short-pod' variety has a slightly wider pods, and thicker leaves than the 'long-pod' variety. Both varieties have a yellow trumpet shaped fl ower, but the fl ower of the 'long-pod' variety has a deeper hue of yellow than the 'short-pod' fl ower. The fruits of the 'short-pod' variety mature in late summer to early autumn while the fruits of 'long-pod' variety mature in late winter to early spring. The more widespread nature of the 'short-pod' variety could potentially be due to a preference for this variety as an ornamental plant, due to its more presentable foliage characteristics and shorter pods, in contrast to the 'long-pod' variety.

Dhileepan K.,Alan Fletcher Research Station | Trevino M.,Alan Fletcher Research Station | Bayliss D.,Alan Fletcher Research Station | Saunders M.,Alan Fletcher Research Station | And 5 more authors.
Biological Control | Year: 2010

Carvalhotingis visenda (Hemiptera: Tingidae) is the first biological control agent approved for release against cat's claw creeper Macfadyena unguis-cati (Bignoniaceae) in Australia. The mass-rearing and field releases of C. visenda commenced in May 2007 and since then more than half a million individuals have been released at 72 sites in Queensland and New South Wales. In addition, community groups have released over 11,000 tingid-infested potted cat's claw creeper plants at 63 sites in Queensland. Establishment of C. visenda was evident at 80% of the release sites after three years. The tingid established on the two morphologically distinct 'long-pod' and 'short-pod' cat's claw creeper varieties present in Australia. Establishment was more at sites that received three or more field releases (83%) than at sites that received two or less releases (73%); and also at sites that received more than 5000 individuals (82%) than at sites that received less than 5000 individuals (68%). In the field, the tingid spread slowly (5.4. m per year), and the maximum distance of C. visenda incidence away from the initial release points ranged from 6. m to approximately 1. km. © 2010.

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