Comment on State Government’s policy limiting riparian revegetation within the Yarra Valley

Along with several of my colleagues from the Waterway Ecosystem Research Group, we were quoted in a recent Age article on recent State Government policy limiting riparian revegetation within the Yarra Valley:

Wetlands ecologist Joe Greet in a waterway near Woori Yallock, where the banks have eroded due to a lack of vegetation.http://www.smh.com.au/technology/sci-tech/states-controversial-vegetation-policy-bad-news-for-environment-scientists-say-20170215-gudq4v.html

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Controlling Phragmites

Phragmites or Common Reed (Phragmites australis) is a natural component of many wetlands but can be highly invasive. I recently worked on a project with Paul Rees from Melbourne Water at the Ramsar-listed Seaford Wetlands (Melbourne, Victoria), where Phragmites is encroaching into important mudflat habitat areas which are critical for migratory birds. We assessed the efficacy of slashing as a means of controlling Phragmites by establishing twelve 5 m x 5 m quadrats within mature Phragmites reed beds and slashing half of them. The response of Phragmites to slashing was highly variable and dependent on the elevation (i.e. subsequent flooding) of the slashed quadrats. Phragmites regrowth was minimal in lower-lying quadrats which were wholly inundated for several months each of the following two years (to a mean depth of ~22 cm). In contrast, in quadrats of higher elevation, which were mostly only partially or shallowly inundated, Phragmites recovered almost completely within 10 months. In quadrats that were not slashed there was no change in Phragmites cover (i.e. it remained ~100%) irrespective of flooding extent. We propose that prolonged flooding above the height of the remaining stubble is necessary to prevent Phragmites recovery. Thus, slashing may be a successful means of controlling Phragmites when low-lying areas are targeted and these are subsequently flooded to a sufficient depth (e.g. >20 cm) for at least several months.

This study was recently published in Ecological Restoration and Management.

Heading home after a muddy days work!

Heading home after a muddy days work!

Please don’t hesitate to contact me to discuss the project or for a copy of the manuscript.

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Current projects

I am currently coordinating two major projects:

An assessment of methods to promote the restoration of swamp forests at Yellingbo

This project has involved both surveys and experiments looking at ways to promote the success of revegetation within the Yellingbo Nature Conservation Reserve – the last remaining home of the Helmeted Honeyeater and lowland Leadbeater’s Possum. Surveys of previous revegetation have identified factors important for the success of revegetation within the reserve. These include: elevation (water regime), canopy cover/shading, method of protection from browsing, and level of competition from understorey vegetation. Protection from browsing was found to be essential in open areas, and less so in densely vegetated areas, with browsing pressure variable between species depending on their palatability. In general, plantings at lower elevations (in wetter areas of the swamp) and in shaded positions with high levels of competition from exotic or native understorey plants have performed most poorly.

This information has been used to establish three experiments: a comparison of the importance of elevation (water regime) for the establishment of two dominant eucalypts of the swamp; the effect of understorey biomass removal (slashing of Phragmites) on planting success; and the effect of various weed control techniques (matting, mulching, ect.) on planting success. Initial surveys of plantings for these experiments have been completed with follow-up surveys to be conducted later this year.

Determining the main drivers of stream water temperatures in the Greater Melbourne region

I have recently begun work on a review of drivers of water stream temperatures within the Greater Melbourne region. This work has included a literature review on the drivers of urban stream water temperatures, and the collating and modelling of data from over 70 sites within the region. Modeled effects on water temperatures include: air temperature, stream size, riparian cover and proportion of connected impervious surfaces. The ultimate aim of this work (in conjunction with work by a colleague relating stream biota distributions to water temperatures) is to assess the vulnerability of stream biota to anthropogenic impacts on stream water temperatures in urban and peri-urban systems.

 

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Hello

My name is Joe Greet. I am riparian ecologist with a penchant for plants. I am currently employed as a research fellow within the Department of Resource Management and Geography at the The University of Melbourne. I am a member of the Waterway Ecosystem Research Group, which aims to develop tools for achieving healthy streams and rivers in urban and rural landscapes.

I am currently researching appropriate methods to promote the natural regeneration of Eucalyptus camphora swamp forest at Yellingbo – the last refuge of the Helmeted Honeyeater and lowland Leadbeater’s Possum.

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