SUCCESSIONAL WEED MANAGEMENT DISCUSSION PAPER, By Spencer Shaw, Brush Turkey Enterprises, August 2010.
“We must remember that good bush regeneration is not weed control, but that it is the restoration of native ecosystem function.
This may seem like semantics and somewhat philosophical, because weed control is all that we seem to be doing in bush regeneration – but our focus is on ecological management and the restoration of native ecosystem function.
What we should focus on is not so much control of all weeds, but restoring ecological function through control of weeds if and as required.
Some weeds may assist or be able to participate in ecological function and ecological succession for the purpose of restoring native ecosystem function – some weed may have negative and positive functions – for example ourselves!”
DEFINITIONS
Ecological succession, a fundamental concept in ecology, refers to more or less predictable and orderly changes in the composition or structure of an ecological community. Succession may be initiated either by formation of new, unoccupied habitat (e.g., a lava flow or a severe landslide) or by some form of disturbance (e.g. fire, severe storms, logging) of an existing community.
Weed: A plant considered undesirable, unattractive, or troublesome, especially one growing where it is not wanted.
Invasive / Environmental Weed: Applies to non-indigenous species, or “non-native”, plants that adversely affect the habitats and bioregions they invade economically, environmentally, and/or ecologically.
THE CHALLENGE
In reality “weeds” can often be an emotive term for something we don’t like, something that is out of control. To undertake weeding is to remove something unnecessary. We can get angry at weeds for just being there.
Our challenge is to familiarise ourselves with the life cycles and needs of the plants we call weeds and then use this knowledge to better manage our ecological restoration works. Do some weeds even need to be controlled?
Our challenge is to remember that ecological restoration isn’t gardening. Weeds in the garden are considered a sign of neglect. We must look past the weeds and the perception of mess and look to the ecological processes that we can stimulate to deliver short term and long term ecological rehabilitation outcomes.
SO THE QUESTIONS WE SHOULD BE ASKING OURSELVES ARE???
What if Weeds aren’t good plants gone bad?
What if Weeds are just making a living?
What if some weeds are providing a positive ecological function in our natural area management goals?
WHAT IS SUCCESSIONAL WEED MANAGEMENT?
Successional Weed Management is a term that defines the practice that we have evolved that acknowledges that:
1. Some weeds do not inhibit the successional development of some ecosystems and can be either neutral or even positive to native ecological function and succession. 2. That these weeds will drop out of/be out competed by the ecological succession of a site.
CAN SOME WEEDS HAVE A POSITIVE ECOLOGICAL ROLE?
1. Some weeds can create conditions suitable for migratory resilience, i.e. Create habitat for seed dispersing birds and fauna.
2. Create conditions suitable for germination of native plants.
3. Provide food resources for fauna that might prevent population decline.
4. Create improved microclimate suitable for the native ecosystem you wish to restore.
5. Provide soil improvement and host beneficial mycorrhizal communities
6. Create habitat for ground dwelling fauna
SUMMARY OF SUCCESSIONAL WEED MANAGEMENT
WHAT SORT OF WEEDS ARE SUITABLE
1. Weeds that are not invasive of undisturbed native ecosystems
2. Weeds whose reproduction will be limited or cease as ecological succession progresses.
3. Short lived herbaceous annuals
4. Weeds that provide a positive ecological input to native ecosystems that are already under pressure.
NEGATIVES
1. Reduced accessibility for managers
2. Invasive environmental weeds may spread and hinder ecological succession if already established on the site.
3. Can look a bit messy!
POSITIVES
1. Larger area covered for cost
2. Rapid provision of habitat
3. Manages existing systems or conditions rather than trying to establish from scratch.
4. Can reduce off target damage from weed management activities
WHY DOES THIS METHOD WORK SO WELL WITH RAINFOREST COMMUNITIES?
Rainforests are highly competitive ecosystems, with successional processes that may take hundreds if not thousands of years. Apart from the vine weeds such as Madeira vine and Cats Claw creeper, most weeds will be outcompeted rapidly by the growth of native rainforest trees and shrubs.
Annual herbs such as Cobblers Pegs, Thick Head, Milk Thistle, Fleabane will be rapidly outcompeted by these ecosystems even when they look dominant in the first two to three years.
