In our previous newsletter (Spring 2013) we reported on a major project to examine options for improved management of South Australia’s mound springs. Natural Resources, SA Arid Lands has secured $1m through the Australian Government’s Caring for our Country Investment program for the project.
This three-year project, described as the Desert Jewels Project, is investigating, amongst other things, improved grazing management of springs, management of reeds (especially Phragmites) that have proliferated at some fenced springs, weed management (e.g. date palms and polypogon at Dalhousie) and fire management.
The funding application was developed in close consultation with the Friends of Mound Springs. The Friends group developed a project brief which has been incorporated into the much larger Board application.
Progress on this project includes the following:
- A Desert Jewels Project Officer (Sam Gitahi) has been appointed to work full-time on the project under the direction of Travis Gotch. In addition, an Arabana Springs Cultural Officer (Shannon (Sam) Stuart) has been appointed to help coordinate the involvement of Arabana people in the project at springs of interest to the Arabana. Both Sam Gitahi and Sam Stuart commenced work in October 2014.
- A national Mound Springs Data Base is being developed.
- Fish surveys have been undertaken at Dalhousie and potential burn sites have been identified. A remote sensing project is also to be undertaken at Dalhousie – reviewing remote sensing data from the last 20 to 30 years to assess changes in open water habitat.
- As reported elsewhere in this newsletter, the FOMS trip of July 2014 gathered data at a number of mound springs (Outside, Twelve Mile, Fountain, Big Perry, Hawker and Fanny Springs), with observations also at Levi Springs. FOMS members Brendan Lay and Simon Lewis have also met with S Kidman and Co’s General Manager Greg Campbell prior to the FOMS trip to discuss the project.
Some Clues Emerging
A major area of concern in mound springs management is the proliferation of reeds (Phragmites) in springs that were formerly open to grazing but have since been protected. Measurements and observations by researchers and by FOMS personnel suggest that the proliferation of Phragmites in protected springs may be linked with the increased nutrient levels introduced during decades of cattle grazing.
It is also hypothesised that, with prolonged exclusion of cattle, nutrient levels will gradually diminish and Phragmites abundance may decrease.
Implications for Springs Management
A primary focus of the Springs Management Project is the development of management prescriptions that, as a general objective, will maximise habitat diversity in the springs and,
in doing so, will address the perceived negative effects linked with Phragmites proliferation at fenced springs. It is planned that management trials will be implemented to help clarify optimal management prescriptions.
Observations made by FOMS members during the July 2014 field trip (see trip summary elsewhere in this newsletter) and other discussions suggest that the following management trials and related research should be considered.
Outside and the Fountain would be useful trial and/or reference areas as both are showing an apparent decline in Phragmites abundance. One of these springs (e.g. Outside) could be left as a reference area, with a burning trial at the Fountain. Burning half a spring (longitudinally) is seen as a good objective, although it may be difficult to achieve. A logistical issue is that summer burning may be optimal and it may be difficult to secure a fire crew at that time, given priorities elsewhere in the State. Burning would test the theory that fire will hasten the depletion of the Phragmites rhizomes and therefore hasten the decline of Phragmites. A burning trial at Twelve Mile could also be contemplated to test this theory. Further discussion is needed to confirm the best timing for trial burns.
- A noteworthy occurrence at both Outside and the Fountain is the residual mat of Phragmites rhizomes in the spring vents. Even if there is very little growth of Phragmites in these areas, the rhizomatous mats could persist for many years. A trial is recommended to remove a section of this mat at Outside or the Fountain (probably the Fountain, if Outside is left as a reference).
- Some concerns have been raised about the proposal to remove a small section of rhizomatous mat. Those concerns focus on two aspects: (a) possible impact upon invertebrate fauna in the spring sediments; and (b) exposure of the spring sediments to air and oxygenation of sulphur compounds in the muds to form sulphuric acid, with flow-on deleterious effects. In relation to invertebrates, it is proposed that only a small proportion of the rhizome mat be removed, meaning that the bulk of the invertebrate population would not be directly disturbed and should re-colonise the area where the mat is removed. The acid-sulphate soil issue warrants further discussion but the intention would be to remove only a small section of mat in a patch where the sediments would remain submerged. This should limit the risk of acidification.
- Outside Springs comprise several vents, of which one is fenced. Further fencing could be contemplated at Outside to add more information about grazing exclusion in this area.
At Levi Spring fencing of the spring adjacent to the track and rock outcrop would be of interest and could be easily done, as the spring has no significant tail, is on “easy ground” and is currently free of Phragmites. This relatively minor work could provide useful information about grazing impacts and cessation of those impacts.
- In discussion, it has been suggested that fencing of this small spring at Levi could lead to prolific growth of Phragmites. An alternative suggestion has been to fence a larger area at Levi to include other springs also. Fencing of a larger area would be of interest but could be logistically difficult because of rock outcrops. Fencing of the single spring would be a simple task that could provide useful information. At the moment there is nothing really to suggest that it would be rapidly colonised by Phragmites.
- FOMS’ observations at Hawker Springs support the hypothesis that grazing impacts are most pronounced at the outer springs of this large group, diminishing towards the centre of the group. A more rigorous research project at Hawker Springs would provide useful information about grazing impacts. This could be promoted as a University research project.
- FOMS believes that fencing of some of the springs at Fanny Springs should be considered further. This is a fairly linear group of about eight springs and we believe it may be instructive to fence up to half of the springs (within one enclosure) and leave the rest open to grazing.
- It has been suggested that fencing of some of Fanny Springs is not a priority as these are low-flow springs of limited interest. However, FOMS believes this should be considered further. The terrain and linear nature of this spring group means that this is an opportunity to fence on a larger scale than most other fenced springs on pastoral lands and follow-up monitoring could provide useful information for the project.
- The springs at Finniss Springs have been free of significant grazing pressure for twenty years or more. They will undoubtedly be good reference areas but may also be suitable for active management trials. FOMS proposes that there should be joint inspections at Finniss Springs, as soon as possible and before the end of 2014, to consider the merit of Finniss Springs for trials and/or as reference sites.
- An important hypothesis emerging in this work revolves very much around elevated nutrient levels created by cattle access. A good deal of chemical analytical work has been undertaken in the mound springs over the years and this should be reviewed as part of testing the above hypothesis. In addition, a systematic program of nutrient testing is needed in springs with a range of grazing (and non-grazing) histories to help assess the links between cattle grazing, elevated nutrient levels and Phragmites incidence and abundance.
FOMS will continue to work closely with DEWNR personnel and others on this project. The next twelve months should prove very interesting as field trials get under way and FOMS volunteers are likely to play an active part in assisting those trials.