This submission is in support of community input provided to Hepburn Shire Councillors and staff by Friends of Jubilee Lake in response to proposed works. It addresses two related proposals for vegetation management objectives and methods discussed in the FOJL submission from Basil Eliades.
- On going management of blackberry
- New proposals for willow removal at the upstream end of the lake.
The Jubilee Lake environs that the community and visitors love and use has evolved over more than a century since the lake was constructed for mining purposes. That co-evolution has included active plantings, infrastructure and management especially in buoyant economic times but it has predominantly resulted from colonization of degraded mining landscape by vegetation both native and exotic that has spread by natural processes (eg water and wind) active biological agents (birds and animals) and human activity (mostly engaged in passive recreation). This has created a vibrant novel ecosystem that supports a diversity of native and naturalized life, provides critical ecosystem services and is fundamental to the amenity that draws locals and visitors alike.
Like all lakes natural and manmade, a sediment delta at the upstream end of Jubilee Lake is the most biological rich environment that has undergone the most advanced hydrological and ecological succession. These wetlands have also been subject to the least human management and use for obvious reasons.
These delta wetlands would have initially been dominated by water reeds but have been progressively occupied by blackberry and other species as sediment deposition from floods built soil less subject to waterlogging. Willow species, especially Salix fragilis and Salix caprea have been the primary tree colonisers that have largely shaded out blackberries to create “everglade” type novel ecologies that optimize the essential function of sediment capture.
By slowing and spreading sediment from flood flows, the willow everglades are a critically important ecostructure to maintain the deep water environment of the lake for centuries to come.
With a drying climate and greater risk of severe bushfires and more intense storm events (the default climate change prediction for at least two decades now supported by meteorological data) it is imperative that this willow dominated ecostructure be conserved. Any plans to remove or drain this system would be grossly irresponsible. The usual justification for this outmoded anti-ecological “plumbing drainage model” of catchment management is the protection of important infrastructure and buildings inappropriately located on flood plains. In the case of Jubilee Lake these factors are not relevant.
Council engineering and planning staff should be applying Water Sensitive Urban Design principles in this and all other projects involving management of natural and stormwater flows as in now considered standard in the stormwater management industry.
These essential hydrological functions of the willow everglade forest do not preclude management to open some parts of these everglade for better access by people and even small scale earthworks to create further ponds that diversify the wetland habitats while maintaining their sediment capture and water purification functions. Succession beyond willows to taller longer lived trees is an inevitable if slow process. Management could focus on accelerating succession (as we have been doing in Spring Ck for thirty years) by adding suitable species to create a tall and magnificent open forest. Based on our experience we think suitable succession species could include Blackwood, Elm, Californian Redwood, Black Walnut and some species of oak.
The baseline for any management plan to control and reduce blackberry in high rainfall parts of the shire such as Jubilee Lake is to first acknowledge that willows have been the primary and dominant, no cost control on blackberry in the lake precinct by virtue of a dense canopy during the blackberry growing season. Eucalypts do not provide dense enough shade to exclude vigorous blackberry understory while deciduous tree species such as elm, oak, and to a lesser degree native Blackwood do provide more permanent dense canopy that eliminates or reduces blackberry to a weak groundcover.
Vigorous blackberry growth at the edge of dense tree canopy (willow and otherwise) is a perpetual management issue that to some extent is addressed by other shade tolerant shrubs that occupy this niche but many of these are currently treated as weeds such as hawthorn and holly. More appropriate management of these succession species can radically reduce the need to control blackberry at the edges of dense tree canopy
Kicking the herbicide habit
Herbicides (mostly glyphosate) have become the default management tools everywhere leading to degraded and even ecologically dead soils and wetland degradation when used repeatedly. It is no exaggeration to say public land management systems have become addicted to herbicide.
We shouldn’t need to remind council that while many community members have been pointing out the risks of herbicide and especially glyphosate for decades, the mounting scientific evidence and legal decisions on this chemical mean that council officers and councilors must now do their due diligence by considering this evidence in all their vegetation management plans.
Although the opportunity for Hepburn Shire to show leadership and provide some substance to our branding as a place of health and wellness is rapidly passing it is now imperative that ratepayers are protected from potential legal consequences failure to consider evidence on its merits. Council cannot rely on advice from the state and federal levels of government as evidence withheld by industry for decades in exposed in courts around the world.
Mowing, grooming and other mechanical means of blackberry control or burning could obviously replace herbicide to some extent at Jubilee Lake but all have their downsides and are temporary.
Managed Livestock Grazing
There is a real opportunity to seriously consider managed livestock especially goats for a number of reasons.
- Goats are very effective at controlling and eliminating blackberry to create grasslands similar to that achieved by mowing.
- Goats are water phobic and will not voluntarily enter wetland areas.
- Goats are a well established vegetation management alternative to herbicide and machinery in urban and rural areas of California and this industry is becoming established in Australia (Melbourne Water is doing trials comparing goats to herbicide in sensitive riparian environments similar to Jubilee Lake)
- A report to the agricultural advisory committee of Hepburn Shire in 2010 led to allocation of funds to support a grazing service but there was no one to provide that service at the time.
- Council is now the formal partner with Vasko Drogriski and others in a proposed project to support this exact type of service as part of the Pick My Project community development grants program of the Victorian government.
The time is right to make this a reality and Jubilee Lake is an obvious candidate even if it might not be the first place to trial this innovative and ecological method of land management.
While I believe managed goat grazing may have a significant role in management of the Lake Precinct in the future (including the escarpment slopes dominated by open Mana Gum forest) I think training of council staff in understanding successional dynamics that can lead to shading out of blackberry could reduce the long term need for on-going suppression or management whether that be by herbicide, machinery, fire or goats.
The first principle of sustainable and cost effective land management is to learn from nature’s ability to provide ecological services free of charge or effort.
David Holmgren and Su Dennett
You can see the Upper Spring Creek Restoration Project Management Report here.