Biodiversity Assessment - Murchison
Murchison
Introduction
The northern part of the Yilgarn Craton has an arid climate, with mainly winter rainfall (200mm). Two subregions are recognised. The Eastern Murchison (MUR1) comprises the northern parts of the craton's 'Southern Cross' and 'Eastern Goldfields' Terranes, and is characterised by internal drainage and extensive areas of elevated red desert sandplains with minimal dune development. Salt lake systems are associated with the occluded Paleodrainage system. Broad plains of red-brown soils and breakaway complexes as well as red sandplains are widespread. Vegetation is dominated by Mulga Woodlands and is often rich in ephemerals, hummock grasslands, saltbush shrublands and Halosarcia shrublands. The Western Murchison (MUR2) is the 'Murchison' Terranes part of the Craton, and contains the headwaters of the Murchison and Wooramel Rivers, which drain the sub-region westwards to the coast. MUR2 comprises Mulga low woodlands (usually with bunch grasses and often rich in ephemerals) on outcrop, and fine-textured Quaternary alluvial and elluvial surfaces (extensive hardpan washplains that dominate and characterise the sub-region) mantling granitic and greenstone strata. Surfaces associated with the occluded drainage occur throughout, with hummock grasslands on Quaternary sandplains, saltbush shrublands on calcareous soils and Halosarcia low shrublands on saline alluvia.
Summary of overall condition and trend
Both subregions in the Murchison are continental landscape stress class 3 as assessed by the Landscape Health report (1 is most stressed, 6 is least stressed), however, the regional ecologists argue that at should be 2 or higher due to the level of environmental degradation and the small area of land held in reserve. Wetlands are in fair or good condition and the riparian systems are poor to fair. The trend for both wetland and riparian systems is to remain static or decline. Ecosystems and species at risk are subject to a large number of threatening processes, and the trend is not known in many cases.
Summary of priority management/consevation issues.
Management of reserves and parks in the bioregion is generally fair or good, though some issues such as control of feral animals and fires need to be addressed as quickly as possible, as does the need for further survey work.
Natural values
Grazing of native pastures accounts for the vast majority of land -use, although Unoccupied Crown Land, conservation estates and mining are also significant. Special values include calcrete aquifers with endemic faunas of aquatic invertebrates (eg Lake Way system, Jundee, Lorna Glen, Cunyu, Austin Downs and Killara Station). There are 41 vegetation associations (hummock grasslands, succulent steppe or low woodlands) that have at least 85% of their total area within the bioregion. The bioregion is rich and diverse in both its flora and fauna however, most species are wide ranging and usually occur in adjoining regions. A snake (Pseudechis butleri) is the only regionally endemic species of vertebrate. Refugia include Lake Barlee (intermittent salt lake that fills for approximately one year in 10 and provides breeding sites for Banded stilts and other water birds), Wooleen Lake (floodplain lake and associated marshes which is also an important breeding habitat for waterbirds including Gull-billed Terns) and Anneen Lake (large saline brackish lake and marsh with numerous islands and peninsulas which is a significant breeding area for Gull-billed Terns and Whiskered Terns and other waterbirds).
Click here to link to a table of natural values within each subregion
Wetlands
There are 6 wetlands of national importance in the bioregion, all of which are lakes: Lake Ballard, Lake Barlee, Lake Marmion, Wooleen Lake, Breberle Lake and Anneen Lake. The current condition of all the lakes is fair to good with recovery possible provided some intervention occurs. The trend for all lakes is to remain static olthough not enough is known about some lake systems to provide an reliable prediction. The key threatening processes that affect wetlands in the bioregion are grazing pressure, feral animals (goats, foxes, cats and rabbits) and some impact from nearby mining operations on Anneen Lake.
The only wetland of subregional significance is found in MUR2 (Mungawolagudgi Claypan on Muggon Station). It is an intermittent freshwater lake and contains significant Melaleuca uncinata shrublands and vegetation types associated with dunes. Both the condition and trend are static. Goats are a key threatening process, as is changed hydrology (increased inflow of sediments due to erosion of catchment).
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
The principal streams in the Murchison bioregion are Woomeral and Murchison Rivers and their catchments have the same names. Their condition is poor to fair and the trend is declining. Threatening processes affecting riparian systems are grazing (particularly sheep), feral animals (goats, rabbits and foxes), weeds (buffel grass, saffron thistle, thorn apple, mexican poppy), changed hydrology and changed fire regimes.
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
No ecosystems are listed as threatened by WA, however, 43 communities and vegetation associations are thought to be at risk for a variety of reasons. All communities are considered to be static in trend except: Creekline grassy shrublands, Floodplains, Mixed halophytic shrublands, and Saltbush (Atriplex spp.) shrublands. All of these are predicted to decline. Threatening processes include: grazing pressure, changed hydrology, feral animals (especially goats, foxes and rabbits), changed fire regimes, pollution, pathogens, increased vegetation fragmentation and proximity to mining activities. The threatening processes for some communities are not known.
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
One plant (Conospermum toddii) has been declared Vulnerable under WA state legislation. One mammal (Dasycercus cristicauda), one bird (Leipoa ocellata) and two reptiles (Egernia kintorei and Egernia stokesii aethiops) are declared as Vulnerable. Threatening processes that affect plants plants include changed fire regimes, grazing pressure, feral animals (especially goats), weeds and vegetation clearing. Feral predators (cats and foxes), changed fire regimes and vegetation fragmentation are the threatening processes that affect vertebrate animals.
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.
Table: Australia's Important Wetlands (Directory of Important Wetlands of Australia): their type, condition, trend and threatening processes within each subregion.
There is no data available for this table within the bioregion.
Birds
The avifauna of this semi-arid bioregion does not stand out from that of other bioregions with a similar climate elsewhere in Australia. It contains no limited range taxa, a small proportion of the Vulnerable Malleefowl population and almost no introduced birds. Reporting rates of most birds were higher, but there were no trends in any guilds despite the high level of continental stress.
Status: Typical semi-arid avifauna.
Rare and threatened: No major populations.
Increasers: None indicative of landscape health.
Indicators: Emu, Australian Bustard, Banded Lapwing, White-browed Treecreeper, Hooded Robin, Jacky Winter, Grey-crowned Babbler.
Trend: No trends detected.
Scenario: Avifauna probably largely stable within large climatic fluctuations.
Actions: No grazing in representative areas and the adoption of reduced, conservative grazing rates in key habitat across the bioregion.
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 47 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 .468. (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 .45. (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 .4. (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 .66. (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 .6. (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 11. (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 20. (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
Six Nature Reserves, one National Park, one Timber Reserve and 5 areas of Unallocated Crown Land form CALM's conservation estate. The management rank for all types of reserves is 'fair' to 'good': there are no feral predator programs in place, wildfire management facilities are limited by resources, mining exploration is supervised (except for old exploration drill holes which often remain open), and feral herbivore grazing activities still pose a conservation risk in some areas.
Existing conservation lands cover a wide array of surfaces at all levels in the landscape.There are 60 ecosystems or vegetation associations that are high priority to reserve but are not currently represented in CALM estate (of any kind). Constraints on reserve acquisition, include: competing land uses (pastoralism and mining), cost of land and subsequent management, difficulties in identifying biodiversity values (lack of detailed biodiversity pattern data) and significant degradation due to pastoral practices and feral herbivores. The Murchison is Reservation Class 2, but with only 1.39% of area in IUCN I-IV reserve it should be ranked as 'Class 1'. The most important issue relating to reserve management is that of control of feral animals.
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.
Table: Bioregional and subregional priorities and ecosystem priorities to consolidate the National Reserve System and associated ecosystem constraints.
There is no data available for this table within the bioregion.
Off-park conservation for species and ecosystem recovery
There are no recovery plans for Falco peregrinus, Polytelis alexandrae, Minuria tridens, Conospermum todii, Eucalyptus articulata or any stygofauna species. There are a number of recovery plans which do operate within the bioregion, including: Recovery Plan for the Greater Bilby, 1996 Action Plan for Australian Marsupials and Monotremes, Recovery Plan for Mallee Fowl, The Action plan for Australian Birds 2000, A recovery Plan for the Great Desert Skink 2001-2011 and The Action Plan for Australian reptiles. The recovery actions recommended for fauna species include habitat retention through reserves, State lands, or private lands as well as control of feral predators (cats and foxes), curbing of degradation through grazing pressure and by feral herbivores. Recovery actions for flora species and ecosystems differ slightly as control of weeds, suitable fire regimes and a better understanding of life history requirements for all rare flora are required in addition to actions taken for fauna species above. The Murchison bioregion has a priority of 2 (significant off park effort required). However, there are resource constraints and a limited community capacity).
Integrated NRM
The NRM initiatives currently being undertaken include threat abatement planning (e.g. vegetation management plans, pest management), industry codes of practice (in relation to mining and exploration activities), environmental management systems, ecological sustainable product marketing, institutional reform (through the Gascoyne Murshison Strategy and purchase of leases for conservation estate), integration with property management planning, and catchment planning and Landcare through Land Care District committees in the region.
Opportunities for NRM actions include: duty-of-care legislation for leasehold and other lands, rural and industry reconstruction, new tenure and management arrangements, planning with local governments and National Action Plan for Water Quality and Salinity, and ecologically sustainable product marketing (eg. AgWA's EMU process).
The Murchison bioregion has an NRM Priority rank of 1 because there are major constraints to implement effective NRM actions that achieve biodiversity outcomes. Much of the native vegetation is severely degraded through past agricultural practices (primarily sheep grazing) and feral herbivores. The pastoral lands act leases still require the landholder to maintain certain stock levels that do not necessarily fit with conservation values. Pastoral Industry reform is essential to achieve desired conservation outcomes. Awareness of conservation values through education of various industry (mining, pastoral) and members of the public needs to be increased and limited financial resources are also a major constraint.
Map: IBRA map showing frequency of recovery actions (ecosystems).
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.
Table: The contribution of integrated Natural Resource Management to the protection of biodiversity in each subregion: feasible opportunities and comments.
There is no data available for this table within the bioregion.
Further Information & Gaps
Data gaps and research priorities
The highest priority data gaps in the bioregion are the lack of survey data on flora and fauna distributions and population sizes, habitat requirements for many organisms, and quantitative information on the effects of feral animals and weeds, changes to fire regime and mineral extraction on communities of greenstone surfaces.
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
Table: Some major data gaps in each subregion in terms of protecting biodiversity.
There is no data available for this table within the bioregion.
Before you download
Most publications are downloadable as PDF files. Adobe Acrobat Reader is required to view PDF files.
If you are unable to access a publication, please contact us to organise a suitable alternative format.
Key
Links to an another web site
Opens a pop-up window