Prevention is better than cure - controlling emerging Box elder infestations in the Upper Murrumbidgee via a Healthy Rivers Small Grant

The UMDR in partnership with the Australian River Restoration Centre are pleased to have been awarded a Murray Darling Basin Authorities Healthy Rivers Small Grant to address the emerging Box elder threat which is proliferating along the upper Murrumbidgee River.

Box elder forms dense thickets, easily outcompeting other vegetation and even establishing amidst dense reed stands.

Box elder (Acer negundo) is a small to medium sized, often multi-stemmed, deciduous tree that can grow to 20m tall. Box Elder is a serious weed in riparian environments and is a successful and persistent invader once established, displacing native shrubs and trees and preventing their regeneration. Box Elder is quick growing and out-competes other vegetation, mainly by shading, its extensive root system, and creation of a heavy leaf-fall. It can form dense thickets that exclude most other species. It can be recognised by its light green foliage and ‘helicopter-like’ seeds.

The ‘helicopter’ seeds of Box elder are easily recognisable and help this plant spread.

Box elder first proliferated along the upper Murrumbidgee River from seed during a catchment wide flood event in 2016. Since then the species has rapidly spread, successfully invading pristine and dense shrublands and reed beds. Mapping carried out by the UMDR’s adventurous volunteers has shown that currently it is seedlings and saplings (up to 3m high) that predominate, with limited numbers of seeding plants recorded. Worryingly, Box elders are found to be invading high quality (weed free) native vegetation and are now replacing willows as the primary threat to these areas. The concern is that once these mature into trees 8-20m tall, they will alter vegetation structure and degrade water quality during autumn leaf fall.

Box elder proliferating in the riparian zone along the upper Murrumbidgee River.

This project will halt the establishment of Box elder in the upper Murrumbidgee via the employment of skilled and experienced contractors to target source infestations. The project will raise awareness with landholders and provide training to build capacity for the catchment community to be involved in future weed monitoring and control.

Adventurous volunteers working to control a Box elder sapling amongst dense native vegetation.

By addressing this emerging weed, threats affecting Macquarie perch, Murray cod, Trout cod, Murray river crayfish and riparian habitat will be mitigated.

If you are a landholder or community member that would like to be involved with this project, including attending training- please get in touch. {NEED LINK ON BUTTON}