Author
Angela Bownes
bownesa@landcareresearch.co.nz
Bioeconomy Science Institute – Manaaki Whenua – Landcare Research Group
Christchurch
Coauthors
Quentin Paynter, Bioeconomy Science Institute – Manaaki Whenua Landcare Research Group, Auckland, New Zealand
Abstract
Invasive aquatic weeds are a significant ecological, social and economic threat in New Zealand, reducing freshwater biodiversity, impeding drainage and waterflow, disrupting hydropower generation, and interfering with recreational use of lakes and rivers. Yet, despite being one of the most active countries practicing weed biocontrol, we have only targeted one invasive aquatic species, alligator weed (Alternanthera philoxeroides), in the early 1980s. This represents a major gap, particularly since problematic submerged aquatic species such as lagarosiphon (Lagarosiphon major) and egeria (Elodea densa) already have agents developed or released elsewhere. We plan to address this gap by firstly targeting the suite of submerged aquatic weeds invading New Zealand, thus minimising replacement by species occupying the same niche. Our first target, lagarosiphon, using a leaf-mining fly (Hydrellia lagarosiphon), holds promise for success based on results of several pre-release (predictive) studies, and the process to submit a release application is now underway. Looking ahead, egeria is a low hanging fruit, with a leaf-mining fly (Hydrellia egeriae) already released in South Africa. To date, no biocontrol agents are available for hornwort (Ceratophyllum demersum) or elodea (Elodea canadensis), offering great potential for continued international collaboration on biocontrol of aquatic weeds – a cornerstone of success for biocontrol of several aquatic weeds throughout the world.
keywords
aquatic weeds
pre-release studies
novel targets
International collaboration
Highlights
New Zealand is not currently targeting its major aquatic weeds with biocontrol
We plan to remedy this by targeting the suite of submerged aquatic species invading our lakes
International collaboration is crucial in supporting this goal