The Importance of Weeds

An often quoted definition of a weed is a “plant growing in the wrong place.” In one sense this is true, because from a Landcarers’ point of view, many such plants are exotic species growing in native bushland. In many other ways though, the definition is wrong; the weed is a plant growing in the right place, otherwise it wouldn’t be surviving as vigorously as it is.

Often the weeds are occupying a niche in the environment that our disturbance has created and often the weeds are performing environmentally positive roles within the sites that we are working.
Weeds like Alocasia spp., Elephant’s Ears, can be stabilizing creek banks, catching sediment that would otherwise end up in the Lake, extracting nutrients from the system and providing habitat for birds such as Swamp Hens.

In various sites around the Lake, there are examples of the benefits of weeds within reserves; Ringtail Possums build dreys within a dense Morning Glory, Eastern Spinebills feed on the nectar of Lantana flowers, Satin Bowerbird can use dense Lantana for cover and take the blue fruit off Wild Tobacco.

A reserve at new Lambton Heights with a dense infestation of Lantana, Privet and Tobacco Bush, supports Satin Bowerbird, Regent Bowerbird, Brush Turkey, Squirrel Glider, Powerful Owl and numerous Ringtail and Brushtail Possums.

The most important thing we can all do is get to know our sites really well. What native plants are on site? What weeds are there and which weeds threaten the native plant community most?
What native fauna is present on site and where are the nest sites, roost sites and dense thickets of weeds and natives that protect native fauna from cats, dogs and foxes? Where does water flow or pool in storm events?

Secondly, we can start to think creatively with our weeds. Years ago, when I was working on the rainforest regeneration project at Green Point, we had a problem with large amounts of Lantana debris. We also had a problem with too many tracks allowing inappropriate access and a problem with trail bike riders on our regeneration sites. The solution was to pile the Lantana debris on the tracks we wanted to close down, and break up Lantana and stack it in “walls” to prevent trail bike access. Where years ago there was a four to five metre high Lantana thicket, there is now a dense thicket of rainforest regrowth.

The BITT group at Threlkeld is experimenting with cutting and painting Lantana which is growing up trees, clearing the Lantana to a certain height above the ground and leaving the bulk of Lantana in the canopy to dry out and die. This again provides temporary habitat for birds and possums. The group is then planting vigorous native vines such as Pandorea pandorana Wonga Wonga Vine, Clematis aristata Old Man’s Beard and Cissus antartica Native Grape to climb the dead Lantana and maintain the habitat niche for native fauna.

These approaches eliminates the need for green waste removal to landfill, which is expensive and a questionable environmental practice anyway.

Lastly, we need to accept that the best regeneration strategies for both flora and fauna are long term. A ‘Backyard Blitz’ approach to Landcare is not appropriate and is indicative of the mind set that created many of our environmental problems in the first place.