Phragmites australis (common reed) is a cosmopolitan and competitive wetland grass that can tolerate a broad range of environmental conditions. Its tendency to become invasive in wetlands by rapidly forming dense monodominant stands that out-compete other species has made it a focus of research internationally. Disturbances can facilitate expansion of dominant P. australis stands, which can alter vegetation communities through mechanisms such as high evapotranspiration and litter accumulation. This expansion and dominance is occurring in the critically endangered swamps of the Fleurieu Peninsula in southern Australia, which have been anthropogenically fragmented, degraded, and modified. These swamps are of particular importance to rare species such as the endangered Mount Lofty Ranges southern emu-wren. The project was instigated and funded by the Conservation Council of South Australia and the Department of Environment, Water and Natural Resources due to concern that the dense stands of P. australis within the study system (Black Swamp) are impacting on habitat quality for the emu-wren and other threatened biota. Two contiguous areas within the study system, visually representing Phragmites-dominated and mixed communities, with different disturbance histories (grazed 20 and 14 years ago consecutively) were compared to investigate the influence of disturbance intensity (grazing) and monodominant Phragmites on the vegetation communities. The overarching aim of the study was to understand the influence of Phragmites within the Black Swamp and Tookayerta System and to determine the reasons for its expansion in the region. Field, greenhouse and spatial methods were combined to identify the drivers and mechanisms if P. australis dominance and expansion. The two communities were found to be functioning as alternate states of P. australis reedland; which was driving the transition to alternate states by creating a feedback loop, facilitating the succession of the systems. Evidence of these alternate states was given by biotic and abiotic conditions, whose interactions were found to be influencing species composition and density based on the disturbance history timelines of the two communities. Significant differences were found between the two communities in abiotic (including water depth, soil pH, salinity and nutrient conditions) and biotic variables (including vegetation composition, functional groups, litter depth and P. australis productivity). Litter depth and water table had the strongest influence on the alternate states of the two vegetation communities. A conceptual model is proposed to explain the feedback mechanisms between litter and water table that appear to be driving transitions between stable states of P. australis in the study system. One of the potential methods for controlling P. australis in the Fleurieu Peninsula Swamps (cutting and flooding of stems) was also tested with a greenhouse and pond experiment to further investigate these mechanisms of P. australis competitiveness and to optimise the technique for on-ground management. Cutting and flooding the stems was found to reduce P. australis productivity. Expansion of P. australis was apparent in aerial imagery, which was used to support the findings of the study, and further evidence of the alternate states of the wetland system. The findings of this research have already been integrated into conservation management of the critically endangered Fleurieu Peninsula Swamps and follow-up trials of P. australis control will be undertaken by the Conservation Council of South Australia. As managing P. australis is a challenge across its cosmopolitan range, both to control where it is invasive (introduced) and conserve where it is threatened (native), the findings and state-and-transition model proposed here will help inform optimal management strategies.

For the Western Plains of New South Wales, 213 plant communities are classified and described and their protected area and threat status assessed. The communities are listed on the NSW Vegetation Classification and Assessment database (NSWVCA). The full description of the communities is placed on an accompanying CD together with a read-only version of the NSWVCA database. The NSW Western Plains is 45.5 million hectares in size and covers 57% of NSW. The vegetation descriptions are based on over 250 published and unpublished vegetation surveys and maps produced over the last 50 years (listed in a bibliography), rapid field checks and the expert knowledge on the vegetation. The 213 communities occur over eight Australian bioregions and eight NSW Catchment Management Authority areas. As of December 2005, 3.7% of the Western Plains was protected in 83 protected areas comprising 62 public conservation reserves and 21 secure property agreements. Only one of the eight bioregions has greater than 10% of its area represented in protected areas. 31 or 15% of the communities are not recorded from protected areas. 136 or 64% have less than 5% of their pre-European extent in protected areas. Only 52 or 24% of the communities have greater than 10% of their original extent protected, thus meeting international guidelines for representation in protected areas. 71 or 33% of the plant communities are threatened, that is, judged as being 'critically endangered', 'endangered' or 'vulnerable'. While 80 communities are recorded as being of 'least concern' most of these are degraded by lack of regeneration of key species due to grazing pressure and loss of top soil and some may be reassessed as being threatened in the future. Threatening processes include vegetation clearing on higher nutrient soils in wetter regions, altered hydrological regimes due to draw-off of water from river systems and aquifers, high continuous grazing pressure by domestic stock, feral goats and rabbits, and in some places native herbivores — preventing regeneration of key plant species, exotic weed invasion along rivers and in fragmented vegetation, increased salinity, and over the long term, climate change. To address these threats, more public reserves and secure property agreements are required, vegetation clearing should cease, re-vegetation is required to increase habitat corridors and improve the condition of native vegetation, environmental flows to regulated river systems are required to protect inland wetlands, over-grazing by domestic stock should be avoided and goat and rabbit numbers should be controlled and reduced. Conservation action should concentrate on protecting plant communities that are threatened or are poorly represented in protected areas. Cunninghamia (2006) 9(3): 383–450

The communities of seasonal clay-based wetlands of south-west Australia are described. They are amongst the most threatened In Western Australia. It is estimated that >90% of the original extent of these communities has been cleared for agriculture, and the remaining areas, despite largely occurring in conservation reserves, are threatened by weed invasion and rising saline groundwater. Thirty-six taxa are identified as claypan specialists occurring in six floristic communities. Composition was strongly correlated with rainfall and edaphic factors. The most consistent attribute shared between the seasonal clay-based wetlands of south-west Australia, and the analogous vernal pools systems of California, Chile, and South Africa was the widespread conversion of these wetlands to agricultural systems. The south-west Australia wetlands had a richer flora, different lifeform composition, higher species richness but fewer claypan specialists than the vernal pools of California. The diss...

The coastal waters of southern and south-western Australia are home to almost 30,000 km2 of seagrass, dominated by temperate endemic species of the genera Posidonia and Amphibolis. In this region, seagrasses are common in estuaries and sheltered coastal areas including bays, lees of islands, headlands, and fringing coastal reefs. Additionally, extensive meadows exist in the inverse estuaries of the Gulfs in South Australia, and in Shark Bay in Western Australia. This chapter explores (i) how geological time has shaped the coastline and influenced seagrasses, (ii) present day habitats and drivers, (iii) how biogeography patterns previously reported have been altered due to anthropogenic and climate impacts, and (iv) emerging threats and management issues for this region. Species diversity in this region rivals those of tropical environments, and many species have been found more than 30 km offshore and at depths greater than 40 m. Seagrasses in this region face a future of risk from ...