Weed survey of rivers (2007/2008)

OCTOBER 2007 and MARCH 2008

The project's aim was to engage landowners in the upkeep and maintenance of riparian zones on their property. In order to do this and to commence a meaningful dialogue with the landowners in the catchment, some factual and quantifiable data was needed on what maintenance tasks would be required and what resources, time and effort would be needed to continue that work in the future. By demonstrating the process with real outcomes, MRRCI hoped to enhance landowners' capacity to undertake this work.

Professional contractors and MRRCI Coordinators were engaged in spring (when spraying would have the biggest impact on new growth) and then again in autumn (for a follow up), to work in the riparian zones along the rivers and collect data on the maintenance tasks. In addition, data was collected on the general state of the riparian zones, particularly to assess whether past rehabilitation projects were standing the test of time and to identify areas that would benefit from further rehabilitation efforts.

Tasks undertaken included weed control with some minor fence repairs, while noting the following on a per property basis:

  • the maintenance tasks carried out by the contractors,
  • any further follow-up required e.g. unstable trees, erosion and maintenance requirements for fences,
  • the state of previous re-vegetation areas,
  • what materials were used, and
  • how long it took to complete the work.

The two phases of the project were timed to deal with weeds that were actively growing at different times of the year, as well as to record any notable change in condition of the riparian zone over the year of the project. The contractors also mapped any significant weed infestations in the surrounding areas and this information will ultimately contribute towards the weed management strategies of the region.

The recorded data from both phases has now been collated and a summary of this is shown below.

Evidence collected shows that once firmly established, natural vegetation in the riparian zone is self-sustaining. Past projects of fencing to keep stock out and building in-stream structures to slow the water velocity are re-dressing the balance back in favour of the native habitat and have been shown to be rigorous enough to sustain through winter floods and have greatly reduced the amount of bank erosion.

The last hurdle of weed management is the area that falls to a large extent under the control of individual landowners and this survey project will greatly assist MRRCI in tackling these issues.

SURVEY RESULTS

Summary of Riparian State - October 2007

Summary of weeds found in MRRCI catchment October 2007

Summary of Riparian State - October 2008

Summary of weeds found in MRRCI catchment October 2008

  Funding for this project received from the Environment Protection Fund

Additional information