First Hand Experiences in Managing Different ... - Weeds Australia

Case study 7Managing emerging asparagus weeds on the mid-north coastof New South Wales – Asparagus virgatus andAsparagus falcatusPeter Michael, Port Macquarie-Hastings CouncilAsparagus falcatus (sicklethorn) and A. virgatus aretwo emerging asparagus weeds that are currentlybeing managed by Port Macquarie-HastingsCouncil. Whilst they are in low abundancerelative to other vines and scramblers, the Councilis working to ensure they remain ‘[two] lesstransforming vine weeds they have to worry about’.For A. falcatus, Council’s objective is to eradicatethe weed in all instances. It is in the early phaseof establishment (sparse, isolated infestations,largely not yet naturalised) and eradication of theseinfestations is feasible and desirable based on thepotential impact if left unmanaged. By comparison,A. virgatus is more widespread and more difficultto control than A. falcatus. Therefore, Council aimsinstead to protect priority areas from this weed (i.e.areas of high conservation value), and in so doing,target resources systematically (e.g. locate, map,control, monitor) to prevent further spread andgradually reduce local infestations.What is the problem?Asparagus falcatus displaces native vines andscramblers in a range of ecological communities,is tolerant of a wide range of site conditions (e.g.coastal wind, salt water near the root zone, fullsun to deep shade, variable substrata) and isspread by birds and other animals. It, therefore,has the potential to spread widely and invade arange of coastal environments, including cliffs andheadlands, littoral rainforest and wet sclerophyllforest. Infestations usually consist of an established‘parent’ plant (founder) with diffuse cohorts spreadup to 150 m away, but it is likely that the range of! Asparagus falcatus^! Asparagus virgatusCase study sitebird dispersal is much further. Although A. falcatusis quite distinct at maturity, at the seedling stageits sickle-shaped cladodes can be mistaken forother native seedlings such as Morinda jasminoidesA.Cunn. or Podocarpus elatus R.Br. ex Endl.Asparagus virgatus causes impacts to native groundcover and understorey plants. It is capable ofinvading almost all ecological communities thatoccur along coasts and coastal plains. It forms adense mat of water-hogging roots that can preventthe germination and establishment of other species.The root systems and foliage often co-mingle withdesirable vegetation, making access for digging andoff-target damage from foliar spraying problematic.The fine, fern-like foliage provides little surfacearea on which to apply chemicals. Infestations canspread beneath tree roots, rocks and logs, makingphysical removal very difficult.Both species grow in a range of coastalenvironments and can germinate in conditionsfrom full sun to more than 80% canopy closure.How are they managing the problem?Port Macquarie-Hastings Council is activelymanaging these two weeds in public bushland,106