Native Vegetation

We have been monitoring and evaluating how water for the environment is being used to support the unique, diverse and iconic range of vegetation of the Murray–Darling Basin for nearly a decade. Our key learnings are shared here for you to explore.

Introduction Approach Learnings UNDERSTANDING Outcomes E-Water Delivery Management implications

Introduction

Environmental water is used across the basin to support trees, shrubs and groundcover vegetation with water used to enable particular groups of vegetation to grow and reproduce. Over the past eight years we have been monitoring and evaluating the outcomes of using environmental water to support the diversity of groundcover vegetation. Professor Fiona Dyer talks about three key findings in the accompanying video. In brief:

There are a lot of unique and diverse vegetation species in the Basin with 779 taxa recorded and in 2021–22, 45 species identified which had not previously been recorded.
There are 3 distinct groups of vegetation that respond to different inundation patterns with implications for water managers (see below).
First Nations peoples have shared the cultural significance of particular plants, and this presents new opportunities for collaboration.

Professor Fiona Dyer talks about three key findings from her work.

Note: The contents on this page includes summarised text from the following report: Basin-scale evaluation of 2021–22 Commonwealth environmental water: Vegetation. Page number references have been noted throughout the content below for anyone using the full report.

Freshwater wetland with dense aquatic vegetation and trees in a floodplain forest

Stunning mix of submerged, amphibious and terrestrial vegetation at Whealbah, on the Lachlan River in NSW. Photo: Fiona Dyer

Our approach

We use field records of vegetation species and inundation data that are collected by the Area-scale teams to build our understanding of the relationship between environmental water and vegetation species and communities. The vegetation monitoring data are used to describe the groups of plants (assemblages) that are associated with places that have experienced similar inundation regimes over the past 8 years – these are known as hydrological groups. We use these associations to compare what vegetation will exist with and without environmental water. We also single out plants that are important because they are rare or threatened, or those that are important to First Nations peoples.

What have we learned?

There are a lot of plant species across the basin, and our Area-scale teams are still finding previously unrecorded species each year! Through our work we have observed three distinct groups of floodplain and wetland sites on the basis of their hydrology, referred to as hydrological groups, shown below. When you look through the groups, you will see that they are made up of sites from particular Australian National Aquatic Ecosystem types, with the number of sample points also provided.

Group 1: Near permanent water

permanent wetland (3)
permanent tall emergent marsh (1),
permanent lowland stream (1) (all not occurring in any other groups)
river red gum forest riparian zone or floodplain (3)
temporary river red gum swamp (4)

Group 2: Inundated annually or nearly annually for approx 6 months

freshwater meadow (9) (not occurring in any other groups),
coolibah woodland and forest riparian zone or floodplain (7)
river cooba woodland riparian zone or floodplain (2)

Group 3: Inundated every 2 years for 9 months

river red gum forest riparian zone or floodplain (12)
black box woodland riparian zone or floodplain (8),
temporary lake (5),
temporary sedge/grass/forb marsh (3),
permanent lake (1)

shrubland riparian zone or floodplain (1).
coolibah woodland and forest riparian zone or floodplain (3),
temporary river red gum swamp (3),
lignum shrubland riparian zone or floodplain (1)
clay pan (1)

Each of the three groups has a distinct vegetation community associated with it.

Groups 1 and 2 have a greater cover of submerged and amphibious species than Group 3. This reflects the wetter conditions that prevail at these locations.
Group 3 has far more terrestrial and woody flood dependent vegetation reflecting the more intermittent flooding of these locations.

We wanted to know more about how these vegetation groups responded to water for the environment. Figures 1 and 2 below display clustering of all Flow-MER vegetation sample points into the three hydrological groups based on observed inundation regime. The larger symbol represents the centre-point of each cluster. The stark difference between the with and without environmental water is a key finding from our work over the past 8 years.

The figures below display clustering of all Flow-MER vegetation sample points into 3 hydrological groups based on observed inundation regime. Key: Group 1 = near permanent water, Group 2 = inundated annually or nearly annually for approx. 6 months, Group 3 = inundated every 2 years for 9 months.

With environmental water:

Multivariate ordination plot highlighting Group 3 with orange shading on Dim1 and Dim2 axes

Horizontal bar chart comparing proportional cover of six vegetation types across three groups in conditions with water

Graph 1: Vegetation functional group proportional cover (see below for group composition)

Without environmental water:

Multivariate ordination plot displaying Groups 1, 2, and 3 as blue, green, and orange shaded polygons on Dim1 and Dim2 axes

Horizontal bar chart showing proportional cover of vegetation types for Group 3 in dry conditions without water

Graph 2: Vegetation functional group proportional cover (see below for group composition)

Adding water for the environment boosts vegetation diversity

Importantly, 16 water-dependent taxa from the submerged, amphibious and damp functional groups are only found in the wettest of the sample points (Group 1) and 25 are only found at Group 2 sample points. These include the submerged species eel weed (Vallisneria australis) and ribbon weed (V. gigantea) that are unique to Group 1 sample points, and narrow-leaved cumbungi (Typha domingensis) that is unique to Group 2 sample points, as well as a range of amphibious and damp-loving taxa.

When we model the inundation regime that would occur without environmental water, we would not have any sites that have an inundation regime that matches either Group 1 or Group 2 and we would just be left with sites that fit within Group 3.

Our modelling suggests that in the absence of environmental water we would have considerably less cover of submerged and amphibious species across the managed floodplain of the Murray–Darling Basin. This would mean a significant reduction in the diversity of vegetation species and communities.

Functional group composition

Amphibious

Species that either respond to, or tolerate, the presence of surface water. These species usually require flooding for more than 3 months per year, but can survive periods of damp and drying ground.

Aquatic eel weed submerged in greenish freshwater lake

Eel weed (Vallisneria australis)

Tall green cumbungi reeds growing in shallow wetland water

Eel weed (Vallisneria australis)

Submerged

Species that either require permanent water in the root zone or those that live in the water column.

Four-leafed Nardoo plants covering water in a eucalyptus forest wetland

Nardoo (Marsilea drummondii)

Yellow-flowering Ranunculus plant growing in shallow wetland water

Buttercup (Ranunculus undosus)

Dense stands of spiky Eleocharis grass in flooded forest wetland

Commmon spike rush (Eleocharis acuta)

Floating green Ludwigia leaves in still freshwater wetland

Floating primrosle-willow (Ludwigia peploides)

Damp

Species that germinate and establish on saturated or damp ground, but the adult plants don’t tolerate flooding. They grow on ground that has been flooded.

Upright green Mentha australis plant growing on forest floor

Australian mint (Mentha australis)

Small Centipeda cunninghamii plant with rounded flower heads growing in dry, cracked soil

Sneeze weed (Centipeda cunninghammi)

Woody Flood Dependent

Perennial trees or large shrubs that require flooding to complete part of their life cycle.

Dense lignum shrubs growing in shallow floodwater surrounded by trees

Lignum (Duma florulenta)

Silvery-green foliage of Nitre goosefoot shrub with fine branch structure

Nitre goosefoot (Chenopodium nitrareaceum)

Terrestrial

Species with no flooding requirement.

Ruby saltbush (Enchylaena tomentosa)

Silvery green Atriplex vesicaria shrub with rounded leaves growing in an arid field

Bladder saltbush (Atriplex vesicaria)

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Noonamah sampling during wet conditions in November 2020. Photo credit: Angus Macdonald and Will Higgisson.

Understanding vegetation outcomes

Water for the environment is used for a range of expected outcomes for vegetation. Learn more about these outcomes below, and use the dashboard above to see which vegetation outcomes were a focus for water use across the Murray-Darling Basin in 2021-22.

Vegetation condition

Condition is a broad term to describe the overall health or quality of vegetation. Our research studies whether condition is declining, stable or improving.

Vegetation extent

Extent is the area that vegetation are known to occupy. Our research studies whether vegetation extent is declining, stable, or increasing.

Regeneration

Natural regeneration is the natural regrowth of existing vegetation to replace plants which have died. We study how water for the environment can assist this process.

Seed germination

Germination is the process by which a plant grows from a seed into a seedling. Seeds tend to remain dormant until conditions are favourable for germination. 

Health of in-stream habitat

In-stream habitat describes aquatic vegetation, as well other components like wood and rock that maintain the health of a waterway.

Reduce soil salinity

Saline soils are those that contains enough soluble salt to adversely affect the growth of plants and prevent them from regenerating.

Prevent loss of vegetation

We examine how water for the environment can prevent the death and/or decreasing condition of vegetation.

Soil stabilisation

The roots of vegetation maintain plant root mass, which helps to limit erosion, improve soil stability and contributes to soil fertility.

Improve bird habitat

Our work identifies specific plant species that provide adequate cover and protection for bird nests and help provide a food source.

Restoration and/or recovery

Restoration and recovery include improving the health of existing vegetation.

Resilience

Resilience describes the ability for vegetation to recover after a decline.

Inundate habitat

Inundate habitat refers to the delivery of enough environmental flows to inundate instream and/or riparian habitat.

Volume of Commonwealth water for the environment delivered to Murray-Darling Basin regions

Commonwealth water for the environment is used to support vegetation in different regions across the Murray-Darling Basin. View the different regions below the map to learn how the water was used in 2021-22, and the vegetation outcomes it was designed to achieve.

Total Commonwealth environmental water delivered with vegetation outcomes expected

2,214 GL

of 2,786 GL delivered program-wide

Commonwealth environmental water watering actions with vegetation outcomes expected

108

of 160 watering actions program-wide

Broken

Campaspe

Central Murray

Condamine Balonne

Edward/Kolety–Wakool

Goulburn

Gwydir

Lachlan

Loddon

Lower Darling

Lower Murray

Macquarie

Murrumbidgee

Aquatic vegetation with floating lily pads in a river surrounded by gum trees

Aquatic vegetation in the Wakool River after four consecutive years of environmental watering. Photo credit: Robyn Watts, Charles Sturt University.

What does this mean for water managers?

Water for the environment should continue to be managed to maintain wetter hydrological regimes in floodplain and wetland habitats and the diversity of vegetation they support.

Environmental water has played an important role over 8 years in maintaining functionally important assemblages of species and richness of vegetation communities:

Environmental water increases vegetation species and community diversity.

Environmental water was delivered to align with water frequencies needed by vegetation groups, contributing to increased vegetation species and community diversity.

Environmental water helps prevent shifts to ecosystem types that prefer drier hydrological regimes.

Without environmental water, ecosystem types – like permanent lowland rivers, freshwater meadows, permanent tall marsh, and palustrine wetlands* – would be reduced in extent and are likely to shift to different ecosystem types associated with drier hydrological regimes. Environmental water is important for maintaining a diversity of hydrological regimes across the managed floodplain that in turn support distinct functional and structural assemblages of vegetation.

*Palustrine wetlands are what many people traditionally think of as a wetland—they are vegetated, non-riverine or non-channel systems. They include billabongs, swamps, bogs, springs, soaks etc. and have more than 30% emergent vegetation. They are an important part of the landscape and provide habitat and breeding areas for a wide variety of species.

Environmental water increases the resilience of water-dependent vegetation communities.

Environmental water has contributed to longer term resilience of water-dependent plant communities in maintaining the distinct hydrological regimes needed by vegetation communities. For example, without environmental water, drier hydrological regimes would reduce the diversity and cover of submerged, amphibious and damp-loving species which over time, will reduce seedbanks of these water-dependent species, limiting their capacity to recover in the future.

Environmental water influences the response of vegetation communities.

Data collected over 8 years show vegetation communities have distinct functional and community assemblages because of the hydrological regime they experienced – demonstrating a strong response from vegetation to environmental water received.

Meeting Basin Plan objectives

What did Commonwealth environmental water contribute to plant species diversity?

The delivery of Commonwealth water for the environment has played an important role in maintaining a substantial number of native plant species across the Basin.

What did Commonwealth environmental water contribute to vegetation community diversity?

Between 2014-22, there have been significant differences in the functional and structural assemblages of vegetation between sites that received environmental water and those that did not. In the absence of Commonwealth water for the environment, many locations across the Basin would have experienced notably drier water regimes, resulting in substantially less diversity and cover of water-dependent species.

Two field researchers conducting plant survey beside river

Vegetation monitoring taking place near Blanchetown.

Group learning plant measurement using quadrat in bushland

Measuring plants in a quadrat with Alica and Will from University of Canberra. Photo credit: Adam Kerezy

First Nations knowledge is influencing the understanding of culturally significant plants and how environmental water can be delivered to support positive outcomes.

While Commonwealth environmental watering actions have not deliberately targeted plant species because of their cultural significance, watering actions that supported groundcover vegetation have simultaneously supported a range of plant species known to be used by First Nations people.

Fifty-six species that are known to be used by First Nations people were recorded at sample points that received environmental water in 2021-22, 23 of which were unique to sample points that received environmental water. Seven of these species are submerged and amphibious plants that are associated with Hydrology Groups 1 and 2.

There is an opportunity to engage with First Nations communities across the Basin to identify additional plant species that are culturally important and can be supported with environmental water. This could help establish more specific cultural objectives for vegetation outcomes in the Basin, help inform the design of watering actions and contribute to supporting plant species diversity across the Basin.

Key to plant uses: Fo = food; M = medicine; Fi = fibre and shelter (including dye, glue and resin); C = ceremonial or dreaming/story-telling; H = hunting or fishing; B = basket weaving.

Latin Name

Common name

Use

Submerged

Phragmites australis

Common Name

Common reed

Use

Fo, Fi, C, H

Typha domingensis

Common Name

Narrow-leaved cumbungi

Use

Fo, Fi, C

Amphibious

Carex appressa

Common Name

Tall sedge

Use

Carex tereticaulis

Common Name

Basket rush

Use

Cycnogeton procerum

Common Name

Water ribbons

Use

Juncus usitatus

Common Name

Common rush

Use

Nymphoides crenata

Common Name

Wavy marshwort

Use

Woody flood dependent

Acacia dealbata

Common Name

Silver wattle

Use

Fo, M, Fi

Callistemon sieberi

Common Name

River bottlebrush

Use

Terrestrial

Chenopodium

Common Name

Goosefoot

Use

Chenopodium curvispicatum

Common Name

Cottony saltbush

Use

Fo, M

Chloris truncata

Common Name

Windmill grass

Use

Eucalyptus populnea

Common Name

Bimble box

Use

Glycine clandestina

Common Name

Twining glycine

Use

Goodenia

Common Name

Goodenia

Use

Hypochaeris glabra

Common Name

Smooth cats’ ear

Use

Melaleuca lanceolata

Common Name

Moonah

Use

M, C

Nicotiana suaveolens

Common Name

Native tobacco

Use

Panicum decompositum

Common Name

Native millet

Use

Themeda triandra

Common Name

Kangaroo grass

Use

Variable

Cardamine

Common Name

Bitter cress

Use

Eleocharis

Common Name

Spike-rush

Use

Fo, Fi, H, B

Rorippa

Common Name

Marsh cress

Use

Recommended adaptive management actions:

Actions related to environmental water

Continue to support vegetation species and community diversity at the Basin-scale by delivering environmental water to maintain hydrological regimes at key floodplain–wetland locations.

Actions related to further research

Consider how to use environmental water to further support plant species known to be used by First Nations people.
Engage First Nations communities across the Basin to further identify culturally important plant species that can be supported with environmental water.
Better understand and evaluate the influence of watering actions on responses from vegetation communities by improving the accuracy of sub-annual inundation data.
Establish key hydrological metrics to support the evaluation of vegetation outcomes in areas where riverine vegetation is the focus of environmental water management.

Underwater view of submerged aquatic plants in a freshwater habitat

Under the surface at Bayil a lignum dominated wetland in Gayini. Photo credit: Skye Wassens.

Knowledge Catalogue

News

Basin-scale

Native Vegetation

February 27, 2025

How asking ‘what is good?’ in non-woody vegetation research helps inform water management

This Flow-MER project developed a structured framework for assessing the condition of non-woody vegetation that incorporates ecological data and social values.

Managing aquatic meadows in the Lowbidgee

In the Lowbidgee, aquatic meadows flourish with diverse plants and wildlife, supported by innovative water management and community efforts.

Associate Professor Damian Michael

Professor Skye Wassens

Monitoring at Moon Moon – diverse vegetation and poems about tiger snakes!

At Moon Moon Swamp, diverse native plants thrive despite dry conditions, showcasing resilience and the impact of translucent water flows.

Why are we drawn to rivers, wetlands and floodplains? What role do plants play in making these places special? Tell us what you value (particularly about plants!)

Discover the unique ways people connect with rivers, wetlands, and floodplains, and how these values shape conservation efforts for non-woody vegetation.

We’re all in this together: Have your say about evaluating vegetation outcomes to environmental flows

Cherie Campbell's project evaluates environmental water's impact on non-woody vegetation in the Murray-Darling Basin, aiming to improve future water management.

Dr Cherie Campbell

Read Article

Goulburn River and Northern Victorian Tributaries

Native Vegetation

November 17, 2020

Assessing soil and plants from the sky: Drone monitoring in the Murray Darling Basin

Drones revolutionize riverbank monitoring, providing detailed insights into erosion, vegetation changes, and the impact of water management practices.

Neil Sutton

Dr Geoff Vietz

Read Article

Webinars

Breathing roots, shifting waters: Tracking tree evapotranspiration in response to hydrological dynamics

Join us for a journey over the last 15 years to understand why measuring water use of riverine trees, using sap flow and water balance methods, provides a robust way to investigate the capacity of trees to respond to altered hydrology. Hear how this method is moving away from the traditional condition index metrics that have been used, to an improved understanding of a tree community’s adaptive capacity to respond to change and when they might be heading to an altered state and require intervention.

Watch Recording

Basin-Scale Reflection: Vegetation

Watch Recording

Environmental Water: Supporting the right plants in the right places

The vegetation that occurs along floodplains and wetlands is highly valued for the ecological and cultural benefits it provides. A combination of land use changes and flow modification has had a detrimental effect on the condition of vegetation across many of the world’s large river systems. Environmental flows are used across the Basin to improve the condition and diversity of floodplain and wetland vegetation. Our evaluation investigates the vegetation outcomes from the use of Commonwealth environmental water over the past 9 years in the Murray Darling Basin. We demonstrate a relationship between inundation regimes and the plants that we see in wetlands and floodplains and in doing so, show how environmental water is being used to maintain a diversity of important plant species across the Murray-Darling Basin.

Watch Recording

Integrating technology into wetland vegetation monitoring

A multi-disciplinary team from the Centre for Applied Water Science at the University of Canberra have been developing methods to estimate wetland plants and their response to environmental water using drone imagery and machine learning. Dr Will Higgisson will present on a method developed to estimate the percent cover of common reed (Phragmites australis) and a measure of condition and cover of tangled lignum (Duma florulenta). This webinar will provide the background to this work, the processes we took, and the potential application of these methods.

Watch Recording

Spatial and temporal assessment of floodplain vegetation response to floods

The aim of this study was therefore to assess post-flood vegetation responses as a result of two key flood periods – 2016 and 2022. Multiple sources of remote sensing data was coupled with field measured evapotranspiration to identify inundation areas and assess tree condition.

Watch Recording

Managing for non-stationarity in floodplain-wetland systems:

Resilient variability in non-woody vegetation responses.

Watch Recording

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