Ecological, economic and social considerations of spray control for Hymenachne

Summary

This is an action research project that aims to determine the ecological effects of current Hymenachne spraying regimes and ecosystem responses to the removal of the aquatic Weed of National Significance, Hymenachne. Working with graziers, State agency staff and local government pest control officers, the project team will use the results obtained to develop and disseminate best practice tools to improve Hymenachne control.

Aims

Project objectives:

1. A detailed review of literature will report on issues including, but not limited to, the current spread of hymenachne, existing methods for control, available data on
ecological consequences of spray regimes and the socio-economic impacts of the weed and different control measures.
 

2. The ecological component of the study will address the following research questions:
(a) What are the adverse ecological impacts associated with chemical spray regimes (e.g., decline in water quality, changes to aquatic habitats, loss in vertebrate & invertebrate biodiversity)?
(b) What is the extent of system recovery in the short term, following spray and/or successful hymenachne control (possibly including recolonisation by native vegetation)?
(c) How effective is Weedmaster Duo (an aquatic herbicide) in controlling hymenachne?
 

3. The key research questions for the economics component relate to the knowledge, barriers and incentives that will generate participation in control strategies:
• Quantifying the economic costs of control and the level of incentives needed to generate effective participation
• on-farm economic losses due to lost production where Hymenachne is removed from ponded pastures
• costs of control measures
• types and levels of incentives needed to encourage on-farm control activities,
• the structure of incentive mechanisms needed to generate sufficient participation by landholders at a landscape scale.
 

4. The investigation of broader social issues regarding hymenachne will include questions such as:
• What is the current level of awareness & perceptions of the hymenachne problem in central Queensland by landholders?
• What is the extent of willingness to participate in control programs?
• What barriers, catalysts and enablers influence landholder adoption of, and/or cooperation with, hymenachne control regimes?
• An analysis of conflicts of interest existing in regards to hymenachne as (a) a ponded pasture grass used for livestock production and (b) an ecologically destructive weed of national significance
• Investigations of strategies that could be put in place to foster greater awareness of the weed problem, cooperation across stakeholder groups and a wider adoption of control

Background

Hymenachne, a Weed of National Significance, is an aquatic pest plant that is invading northern Australian wetlands and waterways.  Its proliferation is associated with serious ecological issues and there are substantial costs associated with its control.  However, Hymenachne is also  valued by some livestock producers as a ponded pasture important in drought management.

A significant challenge for the control of Hymenachne is to balance the economic, social and environmental costs and benefits of its use and management.

This project is using science-based techniques to assess the ecological, social and environmental aspects of current  Hymenachne management to improve its management into the future.

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