Biodiversity Assessment - Simpson Strzelecki Dunefields
Simpson Strzelecki Dunefields
Introduction
Summary of overall condition and trend
The overall condition of the bioregion is fair and the trend static with continental landscape stress classes ranging from 3 to 6 as assessed by the Landscape Health report (1 is most stressed, 6 is least stressed). The main land uses are pastoralism and conservation. The South Australia portion of the bioregion in particular has extensive land held in National Parks and Wildlife conservation reserves. Species decline has been appreciable in the past, with the loss of a number of critical weight range mammals, related to fox and feral cat predation, and habitat degradation associated with introduced herbivores.
Summary of Conservation Priorities
A system of integrated management of river channel and floodplain ecosystems is required that will provide economic security for pastoralists while maximising protection of biodiversity. These are among the most threatened ecosystems in the bioregion.
There is an ongoing program of controlling discharge and distribution of artesian water that is supported by the Lake Eyre Basin Strategic Plan and the Great Artesian Basin Strategic Plan. Related to this is the issue of the creation of new stock water points in previously ungrazed or lightly grazed areas and how it impacts on native species.
Arid dunefields and sandplains with sparse shrublands and Triodia hummock grasslands. Zygochloa paradoxa (sandhill canegrass) on deep sands along dune crests. Large salt lakes, notably Lake Eyre, and many clay pans are dispersed amongst the dunefields. Several significant arid rivers terminate at Lake Eyre, in particular Cooper Creek and Warburton Creek. They are fringed with woodlands of Eucalyptus coolabah ssp. arida (coolibah) and Acacia salicina (willow wattle) and shrublands of Muehlenbeckia florulenta (lignum). The bioregion contains seven subregions (Simpson-Strzelecki Dunefields P1 - SSD1, Simpson Desert - SSD2, Dieri - SSD3, Warriner - SSD4, Strzelecki Desert - SSD5, Central Depression - SSD6 and Bulloo Dunefields - SSD7).
Natural values
The extensive dunefields provide habitat for several small nationally threatened mammals including Dasycercus hillieri (Ampurta), D. cristicauda (Mulgara) and Notomys fuscus (Dusky Hopping-mouse). The bioregion also contains a population of the nationally threatened Petrogale xanthopus xanthopus (Yellow-footed Rock-wallaby). Ctenophorus maculosus (Lake Eyre Dragon) is restricted to Lake Eyre and surrounding playas.
A major feature of the bioregion is Lake Eyre. This salt lake is the terminus for one of the largest endorheic drainage systems in the world and a major breeding area for waterbirds during periods of inundation. Along with Lakes Blanche and Frome it provides significant refuge for these waterbirds. The Hay River in the Northern Territory is one of the few remaining relatively pristine watercourses in central Australia.
Click here to link to a table of natural values within each subregion
Wetlands
The six nationally important wetlands in the bioregion are Lake Eyre, Lakes Callabonna and Frome, Diamantina River Wetlands, Lake Phillipi, Lake Torquinie Area and the Mulligan River - Wheeler Creek Junction. The wetland types represented are permanent rivers, seasonal and irregular rivers, riverine floodplains, intermittent freshwater and saline lakes, permanent freshwater ponds and shrub swamps.
The overall condition of these wetlands is good and the trend is static. The main threatening processes are high numbers of feral animals, grazing impact and, particularly with Strzelecki Creek, petroleum and gas exploration and production.
At least fifty other wetlands have been recognised as significant at the subregional level, though the paucity of wetland information for much of the bioregion represents a major knowledge gap.
Nationally important wetlands
Map: IBRA map showing DIWA locations, towns, subregions, major roads and reserves and most common threatening processes.
Click here to link to a table of Australia's Important Wetlands (Directory of Important Wetlands of Australia): their type, condition, trend and threatening processes within each subregion.
Regionally important wetlands
Click here to link to a table of provisional identification of wetlands of regional significance: their type and special values within each subregion. The reliability of the overall subregional assessment is indicated.
Click here to link to a table of provisional identification of wetlands of regional significance: their condition, trend and threatening processes within each subregion.
Riparian Zones
Several major watercourses traverse the dunefields of this bioregion and represent the lower reaches of some of the most significant inland Australian river systems. All flow only irregularly. The Warburton Creek drains from Goyder Lagoon (in the Channel Country bioregion), which itself is fed by the Diamantina and Georgina Rivers of northern Australia, into Lake Eyre. The Cooper Creek also leads into Lake Eyre, though floodwaters rarely carry this far down its long course.
All are in fair condition and the trend is static. The major threats are feral animals and total grazing pressure.
Map: Riparian threatening processes.
Click here to link to a table of riparian zones: their average condition, trend and threatening processes for each subregion. The reliability of this overall assessment is indicated.
Ecosystems at risk
Nine ecosystems have been assessed as being at risk within the bioregion. The only endangered ecosystem is the 'Communities associated with Mound Springs'. These are evident in the Strzelecki Desert subregion in the vicinity of Lakes Callabonna and Blanche. The remaining ecosystems are a mix of eucalypt woodlands with grassy understorey associated with river channels, arid acacia woodlands, other low woodlands and shrublands on sandplains and a sparse herbland on claypans.
All are declining in condition with the dominant threat being total grazing pressure. Minor or specific threats include tourism and altered fire regimes, while for mound spring communities reduced artesian flows are a serious concern.
Map: IBRA map showing frequency of threatening processes for ecosystems.
Click here to link to a table of provisional list of threatened ecosystems in Australia: their broad vegetation type (National Vegetation Information System - Major Vegetation Subgroup), recommended status, current legislative protection as a threatened ecosystem, trend and bioregional distribution. These ecosystems are arranged in the bioregion of their principal occurrence. The reliability of the recommended status is indicated.
Click here to link to a table of provisional list of threatened ecosystems in each subregion: their threatening processes.
Click here to link to a table of provisional list of threatened ecosystems in each subregion: their recommended recovery actions
Species at risk
Trends for all, where known, are declining except for Acacia peuce (waddy wood), which is improving in the Simpson Desert subregion.
The main threats to the plant group are total grazing pressure, poor regeneration and seed set and altered fire regimes. The birds are threatened mainly by loss of habitat associated with grazing, predation by foxes and feral cats, disturbance from humans and, in the case of waterbirds, potential increases in water extraction upstream in the major watercourses. The mammals are also threatened by predation from introduced animals and habitat destruction by introduced herbivores. In addition they face competition for resources with introduced herbivores, particularly rabbits, and isolated populations are more susceptible to local extinction.
There is a total of 29 threatened species in the Simpson-Strzelecki Dunefields. These are made up of:-
| Taxa Group | Commonwealth Rating | State/Territory Rating | |||
|---|---|---|---|---|---|
| Endangered | Vulnerable | Endangered | Vulnerable | Total | |
| Plants | 1 | 7 | 0 | 3 | 11 |
| Birds | 0 | 2 | 1 | 8 | 11 |
| Mammals | 1 | 6 | 0 | 0 | 7 |
| Reptiles | 0 | 0 | 0 | 0 | 0 |
| Amphibians | 0 | 0 | 0 | 0 | 0 |
| Total | 2 | 15 | 1 | 11 | 29 |
Map: IBRA map showing frequency of threatening processes for species.
Click here to link to a table of species at risk in each subregion: their status, trend and subregional distribution. The reliability of the assessment of trend is indicated and whether recovery plans have been prepared.
Click here to link to a table of species at risk in each subregion: their threatening processes.
Click here to link to a table of species at risk in each subregion: their status recommended recovery actions.
Eucalypts and Acacias
No subregions in this bioregion contain endemic eucalypts or acacias. Nor are there any that have been identified as being particularly rich for these genera.
Birds
Sand dunes do not support a wide variety or number of birds, but those of the Simpson-Strzelecki Dunefields include a number of distinctive taxa. The bioregion is particularly important for Eyrean Grasswrens, and moderately important for populations of several limited-range species that area characteristic of chenopod shrublands. There are few exotic birds in the bioregion and little evidence of environmental change. Few guilds changed in reporting rate. The bioregion had higher than average rainfall during both Atlas periods, which may explain why many waterbirds, including the Vulnerable Painted Snipe, were recorded in what is one of the most arid regions in the country. During wet periods, many itinerant waterbirds breed on the ephemeral inter-dune swamps.
Status: Relatively small arid-adapted bird fauna except for ephemeral wetlands.
Rare and threatened: Eyrean Grasswren in cane grass on dunes.
Increasers: None indicative of landscape health.
Indicators: Emu, Australian Bustard, Banded Lapwing, Jacky Winter, Hooded Robin.
Trend: Decrease in reporting rate of freshwater species and migratory waders.
Scenario: Overgrazing of chenopod shrublands has happened in the past but current avifauna now largely stable within the wide range of climate-driven variation.
Actions: No action evident beyond existing attempts to control rabbits.
Click hereto download a summary report including the physical characteristics of the bioregion, a species list, and summary statistics [Excel file]. The file may open on your screen. To save it to your system 'Save as' under the File menu.
Mammals
Number of species and status
There are 44 mammal species within this bioregion. (The maximum number of species recorded in a bioregion is 86 and the minimum is 25).
Click here to link to a table of number of species in each status class for this bioregion.
Click here to link to a list of mammal species and their status for this bioregion.
Critical weight range
The critical weight range (35 - 5500 g) of mammals is the size range of Australian mammals that have been most affected by environmental changes following European settlement. In this bioregion, the proportion of mammal fauna within the critical weight range is .432. (The maximum proportion of fauna within the critical weight range recorded in a bioregion is 0.632 and the minimum is 0.222).
Faunal Attrition Index
Faunal attrition is a measure of contraction or loss of species richness with a region. A high index value means many species have declined or are extinct in the bioregion. The index can be used to compare the status of mammal fauna to regional attributes such as changes since European settlement and average annual rainfall. The Faunal Attrition Index for mammals in this bioregion is .31. (The maximum faunal attrition index value recorded in a bioregion is 0.66 and the minimum is 0).
Click here to link to a table of Faunal Attrition Index for groups of mammals shows the contributions of each group to overall patterns of faunal decline.
Faunal Contraction Index
A range contraction index is a measure of the extent to which the range inhabited by a particular species has contracted. A high index value means that many of the species comprising the region's original mammal fauna have contracted from a high proportion of the regions they originally occurred in. The faunal contraction index for the mammal fauna in this bioregion is .34. (The maximum faunal contraction index value recorded in a bioregion is 0.51 and the minimum is 0.07).
Faunal Endemism Index
Endemic species are those restricted to certain regions. Regions containing endemic species are considered to have high biodiversity conservation values because opportunities to conserve those species do not exist elsewhere. A high index value means that the species comprising the original mammal fauna typically occurred in few bioregions. The faunal endemism index value for the mammal fauna in this bioregion is .63. (The maximum faunal endemism index value recorded in a bioregion is 0.79 and the minimum is 0.52).
New Endemism Index
Extant (still surviving) species that have undergone major range contractions can be considered 'new endemics'. Bioregions that contain new endemic species are often important refugia for threatened species. The new endemism index for the mammal fauna in this bioregion is .73. (The maximum new endemism index value recorded in a bioregion is 0.93 and the minimum is 0.5).
Table: Translocated Species
There is no data available for this table within the bioregion.
Exotic Mammals
The number of introduced exotic mammal species that occur within this bioregion is 9. (The maximum number of introduced exotic mammal species in a bioregion is 16 and the minimum is 5).
Click here to link to a list of introduced exotic mammal species for this bioregion.
Extinct mammal species
The number of extinct mammal species that previously occurred within this bioregion is 10. (The maximum number of extinct mammal species in a bioregion is 29 and the minimum is 0).
Click here to link to a list of extinct mammal species for this bioregion.
Management responses
Reserve consolidation
There are several major reserves within the bioregion:
- Lake Eyre National Park (SA) conserves the large playa of Lake Eyre (the largest lake in Australia and the fifth largest terminus lake in the world) and a section of the Tirari Desert, an extensive dunefield with numerous claypans. When floods inundate the lake it becomes a breeding ground for vast numbers of waterbirds.
- Simpson Desert Conservation Park, Simpson Desert Regional Reserve (SA) and Simpson Desert National Park (Qld) conserve much of the southern and eastern Simpson Desert, an extensive sandy desert in the driest part of the continent characterised by long, straight and parallel sand ridges and an extensive network of playas in the interdune corridors.
- Strzelecki Regional Reserve (SA) contains a large area of the Strzelecki Desert, an extensive dunefield east of Lake Eyre, and the large playa of Lake Blanche.
The major priorities for conservation are those ecosystems associated with mound springs or major arid drainage lines, and acacia woodlands. The key subregions requiring further conservation are Simpson-Strzelecki Dunefields P1 (which has no reserves) and Warriner (which is only 2.3% protected). The main constraints are competing land use, availability of suitable areas and cost. Pastoralism is the main land use with many large pastoral properties within the bioregion. These properties are only rarely available for purchase and are expensive. The conservation priorities are associated with the most productive country. Their acquisition would mean a significant loss of pastoral production.
Click here to link to a table of comprehensiveness, adequacy and representativeness (CAR) of the National Reserve System in terms of ecosystems and area sampled and a ranking of reserve management. The bioregional priority for consolidating the National Reserve System is based on this CAR analysis and threat.
Click here to link to a table of bioregional and subregional priorities and ecosystem priorities to consolidate the National Reserve System and associated ecosystem constraints.
Off-park conservation for species and ecosystem recovery
The group most in need of recovery actions is those species and ecosystems associated with the major arid drainage lines. They occur as a narrow strip beside the main watercourses - Warburton, Cooper, Kallakoopah and Strzelecki Creeks.
The major recovery actions required include the identification of key sites, the retention of regrowth, fencing of key sites to exclude all large herbivores, research into best practice river channel and floodplain management, and the raising of awareness of the significance of these ecosystems.
The main constraints to this are the loss of pastoral production, the lack of current incentives available to landholders to set aside productive land for conservation, and appropriate levels of government resourcing.
Integrated NRM
Key issues for integrated natural resource management in the Simpson-Strzelecki Dunefields are:-
- the decline of ecosystems associated with major arid drainage lines;
- the creation of new stock watering points in previously ungrazed or lightly grazed areas;
- the uncontrolled discharge and distribution of artesian water; and
- feral animal control.
Current NRM initiatives include:-
- NHT-funded Bushcare Grants for on-ground biodiversity conservation works;
- a duty of care requirement for pastoral lessees within the Pastoral Land Management and Conservation Act 1989 that details their obligations to land management; and
- several major planning mechanisms - Marree Soil Conservation District Plan, Lake Eyre Basin Strategic Plan and the Great Artesian Basin Strategic Management Plan.
The priorities for NRM across the bioregion are:-
- establishment of Heritage Agreements on pastoral leases to protect the ecosystems associated with major arid drainage lines;
- ensure ongoing funding for on-ground biodiversity conservation works;
- research into best practice for integrated management of river channels and floodplains;
- feral animal control - aerial shoots of camels, horses, donkeys and pigs (if present); and
- rip rabbit warrens at key sites.
Map: IBRA map showing frequency of recovery actions (species).
Map: IBRA map showing frequency of recovery actions (ecosystems).
Map: IBRA map showing existing projects part of NRM.
Click here to link to a table of contribution of integrated Natural Resource Management to the protection of biodiversity in each subregion: existing measures and effectiveness.
Click here to link to a table of contribution of integrated Natural Resource Management to the protection of biodiversity in each subregion: feasible opportunities and comments.
Further Information & Gaps
Data gaps and research priorities
The main gaps in knowledge are riparian condition, information on wetlands other than the large playas and main watercourses, threatening processes for many of the threatened plants, vegetation mapping at a consistent scale for the whole bioregion and systematic fauna and flora survey for the Strzelecki Desert. The latter is planned in the next five years as part of the ongoing Biological Survey of South Australia.
References
Environment Australia 2000. Revision of the Interim Biogeographic Regionalisation of Australia (IBRA) and the Development of Version 5.1. - Summary Report. Department of Environment and Heritage, Canberra.
A complete list of references is available by clicking here.
Further information
View the Landscape Health in Australia report.
View the Terrestrial Biodiversity Assessment 2002 report.
Download the Terrestrial Biodiversity Assessment 2002 Database - Biodiversity Audit Data Entry System (BADES), and specifications
Click here to link to a table of some major data gaps in each subregion in terms of protecting biodiversity.
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