Vegetation

  Vegetation
 
Mesocosm site Wonga Wetlands Photo: Ben Gawne

Vegetation Research

The Basin Plan seeks to protect or restore the condition, diversity extent and contiguousness of native water dependent vegetation. In addition to their inclusion in Basin Plan objectives, vegetation responses are critical to achieving other environmental objectives because wetland and floodplain plants provide refuges, breeding habitats and food for aquatic organisms, as well as animals that live permanently or seasonally on the surrounding land. The plants are critical to the processes that maintain healthy ecosystems, especially nutrient and carbon cycling, and water and sediment oxygenation.

The Murray-Darling Basin Watering Strategy aims to maintain the current extent of plant communities and populations of trees, and to ensure they have the resilience to persist through environmental threats and climate changes. We are seeking to better understand the significance of multiple factors—including factors other than environmental flows— that sustain healthy plant populations and diverse communities of water-dependent vegetation across time.

The Strategy is particularly concerned with maintaining the current extent of forests and woodlands comprising four tree species:

  • 360,000 ha of River Red Gum (Eucalyptus camaldulensis);
  • 409,000 ha of Black Box; (Eucalyptus largiflorens);
  • 310,000 ha of Coolibah (Eucalyptus coolabah); and
  • Existing large communities of Lignum (Duma florulenta)

One of the aims is to increase the number of trees at different ages (referred to as ‘tree recruitment’) in the Eucalypt communities, which is a broad indicator that tree populations are reproducing sustainably.

A multi-faceted approach

To analyse how changing flow regimes might affect the composition of plant communities, EWKR’s vegetation research will range from the species level to whole communities, and from long-term time-scales (decades) through medium-term (1-10 years), down to single floods.. Research outputs will be developed and then through collaborations and discussions with water managers ways to incorporate research findings into management processes will be identified, and these will inform the communication of outputs to stakeholders.

EWKR will explore the factors that govern two important structural components of the wetlands and floodplains:

Understorey and wetland plants. Research will aim to define appropriate flow regimes required to support vegetation diversity and to identify other factors that might threaten this diversity.

Trees and other long-lived vegetation. Research will focus on defining optimum flow regimes for the germination of seedlings, and the growth of saplings.

It's harvest time for the EWKR Germination Trial Photo: Paul Brown

 For both groups, the study will analyse how Site characteristics (soil type, climate, and groundwater), increased temperature, and changes in rainfall seasonality could influence flow requirements.

What will the research be used for?

  • Water Managers will be better able to predict how the understorey and canopy strata of vegetation will respond to the supply of environmental water, across species, communities and landscapes through time. It will also give them information about how Basin vegetation responds to the influence of particular flow parameters (such as frequency) and non-flow factors (such as rainfall).
  • The research will feed directly into recommendations for the adaptive management of environmental water delivery to sustain key plant species, strata and populations. It will clarify the development of objectives and targets, selection of indicators, and implementation of monitoring.
  • The broader scientific and water management communities will be able to use the findings in water planning and management. The EWKR Vegetation research program will also generate a range of reports, scientific publications, conference presentations and workshops.

Research activities

From species to communities. The responses of some wetland and floodplain plant species (particularly trees) to different water flows have been extensively reviewedalready. This program will extend this knowledge by focussing on the composition, structures and processes of vegetation communities to analyse how they contribute to broader wetland function

Existing data. Across the Basin, there are numerous datasets that span multiple years and multiple sites. EKWR will combine, explore and build on these datasets where appropriate. This will be an excellent opportunity to collaborate with other organisations and realise the potential of data collected through a variety of monitoring efforts, in some cases lasting decades. Early findings from this data integration and synthesis will inform the field research and laboratory work.

Field work. Field research is planned for four locations across the Basin to cover variation in vegetation responses in relation to climate. This research will also link with other EWKR research programs, for example, by assessing vegetation communities that are important habitats for waterbirds or fish. Local water managers and researchers are working together to select sites and develop research methods. We expect the field work to being in autumn 2017.

 

Seedling mesocosm experiment Wonga Wetlands Photos: Ben Gawne

 

  

PDFFact sheet 6. Work summary (882 KB)