land rehabilitation
Wetland edge plants act like nutrient and soil filters. They are often cleared because they occur on level land.
Revegetation of a bare creek 20 years later. By Jim Tedder of mid north coast farm foresters.
This once degraded pond was repaired by fencing from cattle. Nature did the rest.
This gully floor was cleared for grazing. Natural revegetation was hampered by thick paspalum grass and annual flood flow. Established seedlings were planted and grew rapidly.
A sustainable society depends on healthy soil, water and biodiversity. Left to it's own devices, nature will provide all of these things. Human activity has degraded these resources so extensively that most places we occupy will benefit from site repair. We should also look to mitigate the effects of clearing and developing a house site.
At Ecoliving Design, as part of normal site analysis for a building or garden project, we can quickly assess a property, prioritise land degradation issues and suggest the most efficient and economic remedies. This is enough for many people, but we can then develop detailed management plans if desired. Landcare may provide some of this sort of service for free and also suggest possible sources of funding. Funding is a political, constantly changing variable. It is easiest to obtain where site repair assists threatened species or waterway protection.
Land degradation assessment
When we check out a property we look for these issues:
Biodiversity:
What plant species are on site, both native and weeds? What plant communities and habitats are here/ would have been here originally? Is here potential habitat for threatened species? Are there biodiversity hotspots/ weed alarm bells?
Soil erosion:
What is the current condition of the property, noting slopes and existing vegetation cover? Are there processes here causing erosion - could include overclearing, livestock, poorly stabilised excavation, concentrated runoff from driveways/ stormwater? Are there erosion hotspots? A rule of thumb is that erosion results from overclearing and is exacerbated by steep slopes, hard surfaces, compacted soil (due to vehicles or stock) and change in hydrology (concentration of runoff).
Water issues:
This is linked with soil erosion because eroded soil ends up in creeks and rivers, creating problems with nutrient and sediment. On a site visit we read the landscape and ask, is there permanent water here, and what is it's condition? How does storm water/ flood water behave as it passes through the property? Is there potential contamination of waterways from the property, such as driveway oil, septic, livestock? Again, we look for problem hotspots. A rule of thumb here is that water is purified by soil and vegetation, so good water treatment means water taking as long as possible to pass through soil and healthy vegetation.
Solutions
Solutions almost always involve planting. Sometimes we might correct concentrated storm water flow by spreading it out. Sometimes we build temporary structures to stabilise slopes while plants establish. Otherwise, if the environment is able to support plants, then plants usually fix problems. It's then a matter of choosing which plants and where they're needed most. Nature will provide it's own plants, but if local seed is scarce then the pioneer vegetation will be of low diversity and weedy. Deliberate planting of diverse canopy species quickens the process. You might need to maintain the plants and protect them from grazers while they establish. Common mistakes are lack of follow up maintenance and planting too thinly. The quicker a planting establishes it's own canopy and ground cover, the quicker it becomes almost maintenance free.
Diagram for retaining an eroded bank supporting a driveway. Logs or timber boards staked on contour temporarily catch silt and mulch. Strips of matting Lomandra plants establish behind to form permanent silt & mulch traps. Planted tree species eventually stabilise soil at depth.
