Bushland Weeds Manual - Environmental Weeds Action Network

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44 Chapter 4 Corms, Bulbs and Tubers Case Studies Case study 4.1 Managing the spread of Yellow Soldier (Lachenalia reflexa) in a Banksia woodland Yellow Soldier (Lachenalia reflexa). This study investigated the effectiveness of hand-removal and two herbicide treatments on the control of Yellow Soldier (Lachenalia reflexa). Trials took place in the species-rich Banksia/Jarrah woodland in Shenton Bushland. The impact of each treatment on the native flora was also recorded. Carefully hand-removing Yellow Soldier in Shenton Bushland. Measuring cover of all species in treatment plots The ‘point quadrat’ method (Bonham 1989) was used to determine percentage-overlapping cover (referred to as cover) for all species using 200 points within each plot (2 m x 2 m). There were five replicates of each treatment. Effectiveness of treatments Hand-removal (1998 & 1999) over two seasons left all natives intact but was very labour intensive, reducing cover of Yellow Soldier by only 44 %. It also triggered germination of annual weeds. Wiping the leaves (1998) of individual plants with a 10 % glyphosate solution was not effective and was also very labour intensive. Spot spraying (1999) with metsulfuron methyl at 0.2 g/15 L (5 g/ha) reduced the cover of Yellow Soldier by 65 % in one season and appeared to have no significant impact on native shrubs or herbs including native geophytes. The control (do nothing) Yellow Soldier increased in cover by over 30 % between 1998 and 2000. Percentage cover 55 50 45 40 35 30 25 20 15 10 5 control hand removal herbicide 1998 1999 2000 Year Figure 1. Cover of Yellow Soldier in control, hand-removal and herbicide treatment plots in 1998,1999 and 2000. The bars indicate standard errors. Impacts on natives The herbicide treatments did not significantly affect native shrubs or perennial herbs, with both groups increasing in cover in the treatment plots over two years. Although the impacts of the metsulfuron treatment on native geophytes appeared not to be significant it was difficult to assess. There was a large variation across the trial sites in both cover (which is naturally low), and in species. Of the eight species present only one, Milkmaid (Burchardia congesta), was present in all 15 plots. Leafy Sundew (Drosera stolonifera), Vanilla Lily (Sowerbaea laxiflora), Climbing Fringe Lily (Thysanotus manglesianus), and Haemodorum spp. were present in most plots with Pale Grass Lily (Caesia micrantha) and Red Beak Orchid (Pyrorchis nigricans) occurring only occasionally. Percentage cover 15 10 5 0 control hand removal herbicide 1998 1999 2000 Year Figure 2. Cover of native geophytes in control, hand-removal and herbicide treatment plots in 1998, 1999 and 2000. The bars indicate standard errors. Implications for management Yellow Soldier still comprised 12 % of cover in 2000 therefore indicating that any broad scale application would need to be carefully followed up for a number of years following initial application to ensure reinvasion does not occur. In the species-rich Banksia woodland at Shenton Bushland, Yellow Soldier co-occurs with up to 25 native species in a 2 m x 2 m plot
Chapter 4 Corms, Bulbs and Tubers Case Studies and the current policy is to allow indigenous species to recolonise treated sites unassisted. One of the major weeds that invades sites where bulbous weed control has taken place on the sandy soils of the Swan Coastal Plain is Perennial Veldgrass (Ehrharta calycina). A spray program using Fusilade ® is successfully controlling this weed over much of Shenton Bushland including the study site. Stopping the spread The distribution of Yellow Soldier in Shenton Bushland is not dependent on disturbance, with populations extending into relatively intact bushland (Figure 1, Chapter 2). Preventing spread into undisturbed areas is the primary aim of the control program. Yellow Soldier spreads within the bushland via seed. The populations are generally quite discrete suggesting seed is not easily dispersed over long distances. Table 1. Costing of Yellow Soldier control over time. Source: Brown et al. (2002). Water movement and human activity play a role in the spread. Fire reduces competition from the native vegetation and creates bare areas where the seed can germinate. Fire, however, can also create opportunities for land managers to prevent further spread and establishment. After fire, Yellow Soldier plants are clearly visible and the reduced cover of native vegetation makes the resprouting flowering bulbs an easy target for herbicide control. Understanding the current distribution of the weed allows any new infestations to be recognised, recorded and targeted for control. Note: In this trial, the metsulfuron methyl was, where possible, targeted at Yellow Soldier and not applied as a blanket treatment over all vegetation. This is not a difficult or time consuming task but does require responsible operators with a reasonable knowledge of the flora. There is evidence from other studies that some native species, particularly seedlings, are susceptible to metsulfuron methyl at 5 g/ha (Moore 1999). How the study was used In the two years since the results of the study became available to the Friends of Shenton Bushland, they have secured funding to implement control of Yellow Soldier across the bushland. The map helped provide information for costing the project and indicated clear objectives to funding bodies. The Friends have since hired an experienced contractor with knowledge of the flora who has carried out the work. With approximately one hectare of bushland currently invaded the cost of control is relatively low. In the first year funding was obtained through a state government grant and in the second year the local government authority agreed to fund the follow-up work and should continue to do so until the populations require only occasional hand-removal. YEAR TREATMENT COST/HECTARE AREA COST 2001 Brush-off @ 2.5 - 5 g/hectare + pulse@2 mL/L. $300.00/hectare ~ 1 hectare (from maps) $300.00 2002 Brush-off @ 2.5 - 5 m/hectare + pulse@2 mL/L. $300.00/hectare check 1 hectare $300.00 2003 As above but also consider hand weeding isolated plants. $300.00/hectare check 1 hectare $300.00? 2004 Now only hand weeding isolated plants may be required. check 1 hectare 45
Page 1 and 2: Bushland Weeds A practical guide to
Page 3: Acknowledgments This manual is the
Page 6 and 7: iv Introduction The Banksia, Tuart
Page 8 and 9: 2 Chapter 1 The Project Blue Gum La
Page 10 and 11: 4 Chapter 1 The Project Both Arum L
Page 12 and 13: 6 Chapter 2 Managing Weeds in Bushl
Page 14 and 15: 8 Chapter 2 Managing Weeds in Bushl
Page 16 and 17: 10 Chapter 3 Grass Weeds Many grass
Page 18 and 19: 12 Chapter 3 Grass Weeds Box 3.3 Gr
Page 20 and 21: 14 Chapter 3 Grass Weeds • Transi
Page 22 and 23: 16 Chapter 3 Grass Weeds Control te
Page 24 and 25: 18 Chapter 3 Grass Weeds Rhizomatou
Page 26 and 27: 20 Chapter 3 Grass Weeds Case Studi
Page 34 and 35: Chapter 3 Grass Weeds Management Ta
Page 36 and 37: Chapter 3 Grass Weeds Management Ta
Page 38 and 39: 32 Chapter 4 Corms, Bulbs and Tuber
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Page 60 and 61: Iridaceae Moraea miniata Two Leaf C
Page 62 and 63: Chapter 5 Broadleaf Herbs, Sedges a
Page 64 and 65: 58 Chapter 5 Broadleaf Herbs, Sedge
Page 72 and 73: Chapter 5 Annual Broadleaf Herbs, S
Page 74 and 75: Chapter 5 Annual Broadleaf Herbs, S
Page 76 and 77: Chapter 5 Perennial Broadleaf Herbs
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Page 80 and 81: 74 Chapter 6 Trees, Shrubs and Clim
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Page 96 and 97: 90 Chapter 7 Weed Mapping in Remnan
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94 Chapter 8 Herbicide Use in Bushl
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100 Final Note In the end, environm
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102 References 1 Aarssen, L.W., Hal
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104 References 101 Dixon, B. (2002)
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106 References 204 Mann, R. (1998)
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108 307 The Nature Conservancy (200
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