Hattah Lakes – monitoring reports

Ecology Australia was commissioned by the Mallee Catchment Management Authority (CMA) to undertake the 2022–23 condition monitoring of the Hattah Lakes Icon Site, as part of The Living Murray Condition Monitoring Program. Monitoring encompassed the assessment of tree condition and population, wetland vegetation, floodplain vegetation, lignum condition, waterbirds, non-waterbirds and fish.

This project sought to develop and test methods to estimate the cover and condition of tangled lignum (Duma florulenta) using high-resolution imagery captured with an unpiloted aerial vehicle (UAV). This method was tested at 18 sites in at the Hattah Lakes, Wallpolla Island and Lindsay Island in North-West Victoria during March 2023, including four sites that have been managed with environmental water over the five years prior.

This report describes the targeted survey and monitoring of colonial waterbird nests at 21 lakes across the Hattah-Kulkyne National Park between October 2022 and April 2023.

This project seeks to improve understanding of the relationships between water flow regimes, food and waterbird use of the Hattah Lakes. This report examines significant variation in food webs and productivity between lakes, influenced by kale depth, connectivity and vegetation. The report identifies carp as both an ongoing threat to the ecological health of the lakes, whilst also being a food source for waterbirds.

This study aimed to validate existing models for dissolved organic carbon (DOC) leaching and dissolved oxygen (DO) depletion for the Hattah Lakes system.

Ecology Australia was commissioned by the Mallee Catchment Management Authority (CMA) to undertake the 2021–22 condition monitoring of the Hattah Lakes Icon Site, as part of The Living Murray Condition Monitoring Program. Monitoring encompassed the assessment of five vegetation components (river red gum, black box, wetland vegetation communities, floodplain vegetation communities and lignum) as well as waterbirds and fish communities.

This report describes the targeted survey of colonial breeding waterbird nests at 18 lakes across the HattahKulkyne National Park in late 2021 and early 2022. 

The aim of this study was to determine frog species and distribution across select wetlands at the Hattah Lakes Icon Site following environmental water delivery during Autumn and Spring 2021 and compare to frog survey data collected as baseline data during the pre-watering phase (when four of the five study wetlands were dry).

The aim of this project was to continue the study initiated by the Mallee CMA by:  

• Undertaking detector sampling in 2021-22 at the lakes sampled in the previous year, plus additional control sites, during a period of environmental water provision.
• Refining the new automated bat call analysis program through the collection and incorporation of additional reference calls, and further development of the program to improve identification accuracy rates.
• Analysing the bat calls collected in 2020-21 and 2021-22 to determine species richness, overall bat activity, and activity levels for each species for each lake.
• Assessing the short-term benefits of the provision of environmental water during the inundation phase, by comparing the species richness and activity levels in 2021-22 to that of 2020-21 when the lakes were dry.

This project focused on the numerical modelling of carbon accumulation and transfer in the Hattah Lakes. It applied the modelling approach developed by Water Technology and La Trobe University in 2020 for simulating the dynamics of Dissolved Organic Carbon (DOC) and Dissolved Oxygen (DO) in inundated river floodplains.

The approach is spatially explicit and makes it possible to identify areas with higher hypoxia risk across the study area.

This report details annual monitoring undertaken at Hattah Lakes in 2020–21 for river red gum, black box, wetland vegetation, floodplain vegetation, lignum, fish and birds, and compares to previous years' monitoring results.

This project assessed the long term changes to seedbanks across the Hattah Lakes system and investigated factors that may be limiting germination success.

This report presents the results of the mapping of colonial waterbird nesting and breeding sites across Hattah Lakes. Results from this project will be used to inform water for environment delivery targeting waterbird breeding objectives.

This report details annual monitoring undertaken at Hattah Lakes in 2019–20 for river red gum, black box, wetland vegetation, floodplain vegetation, lignum, fish and birds, and compares to previous years monitoring results.

This report presents the findings of the seventh year of monitoring understorey vegetation response to the delivery of water for the environment in the river red gum and black box communities, and the associated network of wetlands in the Hattah Lakes icon site.

This report presents the results from monitoring black box tree health and seed fall responses from 2014 to 2020.

This report investigated the response of river red gum and black box trees to the delivery of water for the environment to Lake Kramen.

This project presents the results of the 2019–20 survey across the Hattah Lakes and Lindsay, Mulcra and Wallpolla Islands icon sites, including assessing how water for the environment delivery has influenced woodland bird communities in Hattah Lakes.

This project details modelling undertaken to assess potential hypoxic blackwater risks associated with environmental watering events at Lindsay, Mulcra and Wallpolla Islands and Hattah Lakes icon sites.

This report details annual monitoring undertaken at Hattah Lakes in 2018–19 for river red gum, black box, wetland vegetation, floodplain vegetation, lignum, fish and birds, and compares to previous years monitoring results.

This intervention monitoring project mapped feral pig damage to the Hattah Lakes Icon Site. 3,231 diggings around the edges of 18 lakes were surveyed.  Initial findings were that pigs promote weed growth and consume molluscs and crustaceans that are a food source for resident and migratory birds.

This report presents the results from monitoring black box tree health and seed fall responses to water for the environment delivery at Hattah Lakes between 2014 and 2019.

This report presents the result of monitoring undertaken to establish baseline aquatic ecosystems and vegetation condition at eight wetlands in Hattah Lakes.

This project presents the results of the 2018-19 survey and assesses how water for the environment delivery at Hattah Lakes between 2014 and 2017 has influenced woodland bird communities.

This report presents 2017–18 monitoring results of the response of Black box seed release and health to the delivery of water for the environment.

This report details annual monitoring undertaken at Hattah Lakes in 2017–18 for River red gum, Black box, wetland vegetation, floodplain vegetation, Lignum, fish and birds, and compares to previous years monitoring results.

This report assesses changes in bird populations over 2014 to 2017 in Black box woodlands at Hattah Lakes, comparing sites that have been watered with sites that haven’t.

This report presents the findings of the fourth year of monitoring understorey vegetation response to the delivery of water for the environment in the River red gum and Black box communities, and the associated network of wetlands in the Hattah Lakes icon site.

This report presents the results of a three year pilot study investigating the influence of water for the environment on the reproduction and health of black box trees in the north of the Hattah Lakes.

This report presents the condition of understorey vegetation at twenty sites at the Hattah Lakes in 2015–16. The report outlines the methods and results of understorey vegetation composition and tree health monitoring and the development of a vegetation response model.

The report presents monitoring of the vegetation species richness and abundance at Lake Bitterang from 2013, 2014 and 2016 following environmental watering on vegetation condition. The report outlines the survey methods and the survey findings.

This report presents the 2015–16 condition of river red gum and black box communities, wetland and floodplain vegetation communities, the lignum community and fish communities at Hattah Lakes. The report outlines the icon site ecological objectives and evaluates the achievement of these objectives based on the monitoring results.

This report presents the results of waterbird abundance and diversity at the Hattah Lakes and Lindsay–Mulcra–Wallpolla icon sites in 2015–16.

This report investigates the changes in waterbird numbers during the period of February 2014 to May 2016 in conjunction with fluctuating water levels at several lakes within the Hattah icon site.

This study investigates the influence of environmental watering on reproduction and tree health of floodplain Black Box trees in the northern lake system of the Hattah Lakes icon site in 2015–16.

This report presents data from a study of fish movement between Chalka Creek and the Hattah Lakes icon site. The sampling methods are outlined and observations of fish abundance and diversity in Chalka creek and the lakes are presented.

This report presents fish assemblage data from the Murray River and Chalka Creek. The report outlines the methods for sampling fish, eggs and larvae. The results of the study suggest there may be a source-sink relationship between the Murray River and Chalka Creek respectively.