Murray Mouth Estuary Restoration Project

MURRAY MOUTH ESTUARY RESTORATION PROJECT

a project of the Hindmarsh Island Landcare Group Inc. PO Box 9 GOOLWA SA 5214

Application No: 07/17

Project Title: Continuing to improve the biodiversity for OBPs at the 19th Beacon site, Sir Richard Peninsula, River Murray Estuary, South Australia

Final Project Report

Introduction

This is the third consecutive year that we have planted on this site. Our original plantings were approximately 15 years ago and consisted largely of the trees, swamp paperbark and boobialla, that were systematically cleared from this site since Europeans came almost 200 years ago. We believe that this site was a swamp paperbark forest before the 1830s but, being so close to Goolwa, suffered with the advent of paddle steamers (1850 – 1890) followed by cattle grazing on the Sir Richard Peninsula from the 1930s.

Our first grant (2015/16) enabled us to build on the earlier plantings, referred to above as 15 years ago, with a good selection of saltmarsh species. Several species suffered from the storms and high tides of 2016 and our group committed to plant again in 2016/17, using our own resources, to supplement possible losses from the previous year. Fortunately anticipated losses were less than predicted, except for swamp paperbark which cannot tolerate waterlogging at planting. Our second grant (2017/18) has continued our concentration on saltmarsh species. These 2 500 plants were planted on April 5/6 and 12/13 2018. Again we have had high storm tides. It will be interesting over the next 5 years to see how the site develops from this substantial input. There remains much to be done, more species to be added etc and we hope funding for these kinds of environmental works will become easier to obtain.

We have attempted to minimise the risks posed by the autumn and winter storms and will continue to vary our planting times etc to try and maximize plant survival.

Description of the site

The site is a long, (approximately 2.5 kilometres) saltmarsh area on the River Murray’s edge, below the Goolwa Barrage. As such it is subjected to tidal movement which has in the past proved a problem for the establishment of revegetation due to the large tides, particularly those driven by additional wind storms across autumn and winter.

Planting has been concentrated east of the boat-ramp launching area and builds on planting undertaken on several occasions in the past 15 years, some funded through the Orange Bellied Parrot Rehabilitation Project of the Australian and State governments.

Raising the 2 500 plants

The plants for this revegetation project were all raised in our nursery from seed collected locally on Hindmarsh Island by the group. Over the past 17 years, through the Murray Mouth Estuary Restoration (MMER) Project of the Hindmarsh Island Landcare Group, we have developed some expertise in raising saltmarsh plants which we have been using in rehabilitating areas of salt marsh, particularly on Hindmarsh Island.

The plants finally used in this revegetation project were as follows.

Atriplex paludosa 100 marsh saltbush saltmarsh Austrostipa stipoides 250 coastal spear grass saltmarsh Duma florulenta 100 tangled lignum saltmarsh Gahnia filum 200 cutting grass saltmarsh Maireana oppositifolia 50 salt bluebush saltmarsh Melaleuca halmaturorum 450 saltwater paperbark saltmarsh Myoporum insulare 200 boobialla saltmarsh/dune Nitraria billardierei 100 nitre bush saltmarsh Tecticornia arbuscula 800 shrubby glasswort saltmarsh Tecticornia halocnemoides 250 shrubby glasswort saltmarsh

Total 2 500

Atriplex paludosa was used to supplement patches of this species already regenerating here.

Austrostipa stipoides was used to supplement patches of this species already regenerating here.

Duma florulenta was virtually absent from the site after the Millenium Drought. It appears to need a mix of both fresh and saltwater and will not survive in constant saltwater (sea-water). These were planted close to where dead plants were evident.

Gahnia filum was again planted in locations where it should be found. Our previous plantings are surviving here although some are finding it difficult to establish well.

Maireana oppositifolia. Plantings from the previous 2 years are growing quite slowly but remain alive.

Melaleuca halmaturorum was again planted in groups, leaving quite extensive spaces as open ground. These trees were also planted along the levee adjacent to the river proper.

Myoporum insulare was planted on slightly higher ground where there was evidence of natural regeneration.

Nitraria billardierei was planted on slightly higher ground. None presently exist here, so we hope for success with this dense bush that tends to grow on saline edges.

Tecticornia arbuscula was planted here again in large numbers as it was almost completely missing from the saltmarsh ecosystem here due to the grazing that occurred from the 1930s on the Sir Richard Peninsula. This plant is the largest of the saltmarsh species in the region but it has been almost eliminated through grazing. It is very brittle. It provides both habitat and food for neophemas and other bird species. This species is now becoming obvious from previous year’s plantings.

Tecticornia halocnemoides is a food plant for neophemas too, but it almost absent from this location. Previous plantings have survived well.

Planting was undertaken by the HILG planting team.

Funding

Funding from the grant was used to purchase the 2 500 plants from our nursery. Additional funding was used to buy guards and canes to protect some of the plants from rabbits etc.

The Hindmarsh Island Landcare Group provided all the other resources needed as their “in kind” contribution to the project.

We have enjoyed undertaking this project and will continue to rehabilitate this site.

Richard Owen Revegetation Projects Co-ordinator Hindmarsh Island Landcare Group Inc. 06/09/2018

This photo was taken after our 2016 planting at the 19th Beacon site. Swans feeding on the site, the extremely high tide due to a king tide coupled with high winds. The single stakes illustrate the water depth across this part of the site and they mark out where Tecticornia arbuscula was planted so that we can check plant survival in the future. Previous plantings of swamp paperbark are obvious, as are the sand dunes along the south-western edge of the site.

All of our plants are marked, some with single canes when it is not likely they will be eaten by rabbits etc., some with soft plastic guards to protect vulnerable species. Other species in this photo include Juncus kraussii, Samolus repens and Sarcocornia quinqueflora. Across the River Murray in the background is Hindmarsh Island.

These are Tecticornia arbuscula planted in 2018 on the edges of the saltmarsh. When planted they are quite small plants. The stakes allow us to easily see where we planted, as plant density is quite high.

One of the only 3 remnant swamp paperbarks can be seen in the middle distance. Plantings of swamp paperbark from 10 -15 years ago can also be seen in the middle distance. The planting team is working on the natural river levee which is higher than the adjacent saltmarsh. They are planting and guarding swamp paperbark, tangled lignum and nitre bush. Plant species in the saltmarsh are beaded glasswort (Sarcocornia quinqueflora), austral sea-blite (Suaeda australis), sea rush (Juncus kraussii) and saltwater couch.