Ecosystem degradation — caused by land clearing, invasive species, pollution, altered fire regimes and climate change — can often be reversed through active intervention. Three core approaches are: habitat restoration, erosion control and reintroduction of previously endemic species.
Degradation occurs when disturbance exceeds an ecosystem’s capacity for natural recovery:
- Soil compaction, salinisation and acidification reduce plant establishment
- Loss of seed banks and local plant populations prevents natural regeneration
- Invasive species prevent native species from re-establishing
- Altered hydrology (drainage, diversion) changes species composition permanently
Habitat restoration aims to return a degraded site to a functional ecological state, ideally resembling the pre-disturbance condition.
| Activity | Purpose |
|---|---|
| Revegetation with native species | Re-establish plant communities and food webs |
| Weed control (mechanical, chemical, biological) | Remove invasive competitors |
| Fencing to exclude livestock or feral animals | Allow vegetation recovery |
| Reinstating natural hydrology | Restore water flow to wetlands, floodplains |
| Mulching and organic matter addition | Improve soil condition for plant establishment |
| Provision of nest boxes, logs and rock piles | Replace lost structural habitat features |
After active intervention, restored sites typically follow a succession trajectory:
1. Pioneer species colonise bare ground (fast-growing annuals, nitrogen-fixers)
2. Early successional shrubs provide structure and shade
3. Mature vegetation develops over decades as soil conditions improve
4. Climax community approaches — though full recovery may take centuries
Victorian example: Bogong High Plains restoration after alpine grazing ceased has involved revegetation with native snow grass (Poa spp.) and removal of exotic grasses.
Soil erosion destroys habitat structure, reduces water quality through sedimentation and removes the nutrient-rich topsoil needed for plant growth.
| Method | Mechanism |
|---|---|
| Vegetation planting | Root systems bind soil; canopy intercepts rainfall energy |
| Contour banks and swales | Divert water flow to reduce velocity |
| Coir logs and sediment fencing | Physical barriers trap sediment |
| Revegetation of stream banks | Riparian vegetation stabilises channel edges |
| Rip-lines and soil scarification | Break compaction and allow water infiltration |
| Rock chutes in gullies | Reduce erosive energy of concentrated water flow |
Erosion control is often the prerequisite for other restoration activities — vegetation cannot establish if soil continues to erode.
Once the threatening process has been addressed, previously endemic species (those that naturally occurred in the area but have been lost) can be reintroduced.
Example: The reintroduction of eastern quolls (Dasyurus viverrinus) to Booderee National Park (NSW) using feral predator-free fencing, and the local extinction recovery work for Leadbeater’s possum in Victorian mountain ash forests.
APPLICATION: When evaluating a restoration proposal, VCAA expects you to link the approach to a specific ecological mechanism — not just name the technique. For example, erosion control with riparian revegetation ‘stabilises stream banks, reduces sediment load and improves water quality for aquatic species’.
