Vegetation is vital to the health and function of waterways wetlands and estuaries, and is recognised as both a key value and an environmental condition.
The strategy will consider opportunities to enhance vegetation values through on-ground works and other initiatives e.g.
- Planting native vegetation along streams
- Keeping stock out of waterways
- Removing weeds
- Providing occasional overbank flows that support vegetation on floodplains and in wetlands
Vegetation is the general term used to describe a group of plants in any one place. Vegetation is recognised as both a key value and an environmental condition.
Vegetation has social, cultural, inspirational, and functional merit, to the extent that it is fundamental to the quality of human life. Vegetation provides essential ecosystem functions such as the cycling of nutrients, climate regulation and clean air. Vegetation is intrinsically connected to notions of identity, sensory and aesthetic perceptions, evolutionary connection, a sense of place, and meaning and preciousness, as well as survival, security and utility.
Vegetation is vital to the health and function of rivers, wetlands and estuaries. It moderates water quality, is a primary source of nutrients for waterway ecosystems and processes, and provides habitat for numerous instream and terrestrial species.
Change in both the condition and value of vegetation can occur over the long term in response to ongoing environmental conditions such as drought, or rapidly following environmental disturbance such as fire or flood.
As a key value, vegetation refers to vascular vegetation (which includes trees, shrubs, grasses, sedges, rushes, reeds, ferns) and does not include non-vascular vegetation (including algae and mosses). As a key value unto itself, vegetation is defined by its condition, uniqueness and extent.
The status of vegetation is based on a combination of its uniqueness and naturalness, and takes into consideration condition and area and extent.
Vegetation value varies from very low to very high, with much of the higher value areas being in the forested upper catchment and in the large regional parks and wetlands along the Dandenong Creek.
Vegetation value varies from very low to very high, with much of the higher value areas being in the forested upper catchment.
Vegetation value varies from very low to very high. The upper forested areas of the Werribee River and Lerderderg River within Lerderderg State Park contain areas of very high value as a result of the extensive areas of high quality vegetation. The value of vegetation across other parts of the catchment is of low to moderate value as a result of the modified nature of the catchment. Areas of higher quality remnant vegetation along the Werribee River occur below Melton Reservoir in the steeper gorge sections of the river.
Vegetation value varies from very low to very high, with much of the higher value areas being in the forested upper catchments, along the coast of Western Port, and in the large regional parks.
Vegetation value is highly variable. The upper headwaters of the catchment contain areas of very high value intact native vegetation protected within the Yarra Ranges National Park. Other areas of high and very high value are located in the headwaters of tributaries such as Diamond Creek, Plenty River, Watts River, Little Yarra and Hoddle Creek. As the River and tributaries flow from the upper parts of the catchment vegetation value decreases as a result of agricultural activities and increasing areas of urbanisation with vegetation of moderate to poor value.
- Poor water quality
Constant high levels of suspended solids in waterways can reduce the availability of light to aquatic plants, resulting in a decrease in health and species diversity.
- Stock damage
Grazing by stock kills plants, prevents natural regeneration of most native plant species, and leads to soil compaction and destruction of sensitive vegetation environments by trampling. Stock may also disburse weed seeds.
- Grazing damage
By vermin and native animals (in unsustainable populations) can result in species loss and prevent natural regeneration of most native vegetation species.
- Vegetation clearance
Clearance of native vegetation results in destruction of plants.
The health of vegetation deteriorates when it is broken up and isolated into individual or small stands.
Rising saline watertable can kill susceptible native vegetation.
- Waterway condition
Structural changes to waterways and floodplains can result in significant changes in water flow, resulting in unfavourable conditions for native vegetation.
- Weed invasion
Reduces species diversity and may impact on regeneration of native species.
Can kill some native vegetation species and increase the ability of weeds to invade.
- Altered water regimes in waterways
Stormwater inputs increase the amount and strength of water flow in waterways, which damages in-stream vegetation.
Can kill some native vegetation species.
Potential management actions
- Manage vegetation areas
Revegetate with appropriate species waterway and land areas that have limited or damaged vegetation.
- Weed control
Target weeds of national significance, and regionally or locally significant weeds.
- Manage stock
Install fencing to exclude stock from streamside vegetation.
- Reduce populations of introduced pests
Protect vegetation from disturbance and predation by rabbits, goats and deer.
- Protect vegetation
Prevent vegetation clearance.