Biodiversity Assessment - Little Sandy Desert
Little Sandy Desert
Introduction
Red Quaternary dune fields with abrupt Proterozoic sandstone ranges of Bangemall Basin. Shrub steppe of acacias, Thryptomene and grevilleas over Plectrachne schinzii on sandy surfaces. Sparse shrub-steppe over Triodia basedowii on stony hills, with River Gum communities and bunch grasslands on alluvial deposits in and associated with ranges. Includes headwaters and course of Rudall River. Arid with summer rainfall. Two subregions; Rudall (LSD1) and Trainor (LSD2).
Summary of overall condition and trend
The bioregion is continental landscape stress class 6 as assessed by the Landscape Health report (1 is most stressed, 6 is least stressed), although a high proportion of the original mammal fauna is now extinct or declining, vegetation cover is reduced as a result of fires and grazing by feral animals such as camels, weeds like buffle grass are spreading and feral predators (cats and foxes) are ubiquitous.
Summary of conservation priorities
Feral animal and weed control programs need to be implemented, the status of many species and ecosystems needs to be documented, major reserves need to be acquired and there is a the need enter into some form of a co-management arrangements with Aboriginal groups.
Natural values
Savory Creek, and the headwaters of the Rudall River, two desert rivers with near permanent wetlands along their courses. Small permanent rockhole wetlands associated with ranges and uplands are locally significant water sources and have high biological and cultural significance. Small artificial wells constructed as water sources along the Canning Stock Route.
Land-uses in descending order of importance include: Unallocated Crown land, conservation, and grazing of native pastures.
Click here to link to a table of natural values within each subregion
Wetlands
There are three nationally listed wetlands. They are in a fair to good condition with two declining in condition and a third (Pools of the Durba Hills) static. Threatening processes include grazing pressure from feral animals (camels, donkeys and rabbits) and exotic weeds (buffel grass and date palm). Human disturbance and vandalism of cultural features is also occurring. There are five wetlands of subregional significance recognised. They comprise freshwater springs, oases and rock pools, seasonal rivers and streams, and intermittent saline lakes. They are important as the only freshwater for large distances, contain rare and recently described taxa, are significant for the maintenance of ecological processes and have significant historical and cultural values. The condition and trend for four of the wetlands is unknown; the fifth is in fair condition but rapidly declining because of feral animals (Camels).
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
Riparian zones within the subregion are in only fair condition and declining. Buffel grass is common along Savory Creek and Rudall River, and permanent and semi-permanent pools are badly affected by camels. Threatening processes are feral animals (camel, cattle, donkeys and rabbits), weeds (buffel grass) 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 Threatened Ecological Communities are listed in the region, although six ecosystems are at risk. These ecosystems are semi-permanent pools along rivers and creeks (Rudall catchment), rockholes, permanent pools (Durba Hills), riparian zones (Savory Creek), samphire communities (Lake Disappointment) and saline lakes. Most are declining with two considered static in condition. The main threatening processes are feral animals and the associated grazing pressure (rabbit, camel, donkey) and exotic weeds (buffle grass and date palms).
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
Under WA State legislation, 2 mammal have been declared as endangered, and 1 plant and 2 mammals have been declared as vulnerable. Another 9 plants, 2 mammals and 2 reptiles are listed as priority species although the condition and trend of the plant populations is unknown. The Commonwealth lists 2 mammals and 1 bird as endangered, 3 mammals, 2 birds and 2 reptiles as vulnerable. The threatening processes identified for most of the fauna are feral animals (fox, cat) and changes to the fire regime. Rock-wallaby populations are continuing to decline despite a fox baiting programme.
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.
Birds
The avifauna of the Little Sandy Desert resembles that of the Great Sandy Desert and many other semi-arid bioregions. The bioregion has a short bird list, no endemics, limited range or introduced species, and virtually no significant trends in reporting rate for the different guilds. The only change was a decrease in the reporting rate of birds that eat insects off the ground.
Status: A typical semi-arid avifauna that fluctuates primarily with rainfall.
Rare and threatened: No major populations.
Increasers: None indicative of landscape health.
Indicators: Emu, Australian Bustard, Hooded Robin, Jacky Winter.
Trend: Lower reporting rate for ground-feeding insectivores.
Scenario: Possible decline of species affected by changes in fire regime, although most impact may already have occurred.
Actions: Ensure representative areas have an appropriate fire regime to maintain diversity.
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 55 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 .582. (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 .42. (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 .39. (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 .68. (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 .64. (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 22. (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
The 558,448 hectares in conservation estate comprise 4.6% of the bioregion and encompassing seven out of its 32 vegetation associations. The reserve system comprises part of one large national park (Rudall River), but its management standard is ranked as 'poor' as it has no management plan and is rarely visited by staff despite having high tourist visitation. Two Aboriginal communities live within the park (Parnngurr and Punmu, with between 200-500 people), two mining communities live relatively close to the park (Nifty and Telfer), and despite having ongoing feral animal problems with camel and occasionally donkey, no management is undertaken. Formal fire management is absent, although Aboriginal people provide a regular burning regime along roads.
Twenty of the unreserved vegetation associations have a high priority for acquisition. The level of reservation of the 'ecosystems at risk' is unknown. A further six vegetation associations, whilst reserved to some small extent, have a high priority for further acquisition. The associations include hummock grasslands, shrublands, woodlands, samphire succulents at times with scrub, bare areas and salt lakes.
Constraints on acquiring reserves include competing land-uses (such as Aboriginal interests, where reserve acquisition can only proceed under a cooperative management model), mining interests, and limited knowledge of biodiversity values. Reservation of the Carnarvon Ranges was proposed to Government nearly 30 years ago.
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
It is generally recognised that further work is required to document the status and condition of both individual species and ecosystems within this bioregion. For mammals the main recovery actions is feral animal control and fire management, and translocation programs are relevant. Habitat protection and retention on lands under both private and State control is needed, especially for ecosystems at risk and for threatened bird, reptile and plant species. As a related issue, recreational users of the Canning Stock Route are causing localised degradation of camping areas and tracks.
Integrated NRM
Almost no NRM actions exist. Threat abatement planning for vegetation and pest management are very limited, while mining industry codes of practice have been useful in requiring some localised biological work.
Opportunities: Better threat abatement may emerge in co-operative management following recognition of Native Title for desert Aboriginal communities.
Constraints: Mineral tenements may be an obstacle, Land Administration Act in relation to pastoral lands, and low awareness of biodiversity benefits (environmental services and tourism) among community at large.
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
- No region-wide vegetation, environmental geology or soil mapping at better than 1:250 000 scale for conservation planning.
- The floras and faunas of only small areas have been examined in any detail, so there are few detailed data on ecological requirements and life histories of virtually all invertebrate species, plants, persisting CWR mammals, uncommon vertebrate and plant species, and ecologically dominant plant species (eg hummock grasses). There are little data to provide a regional context on population-trends for even ecologically significant species (e.g. native rodents, dasyurids, spinifex reptile communities, termites, ants, camels, foxes and weeds such as buffel grass).
- No data on the fauna/flora of small permanent rockhole wetlands or on aquatic environments of the Rudall River and Savory Creek. There is no quantitative data on the impact of camels, donkeys and rabbits on aquatic systems or other communities, especially effects on invertebrate and non-vascular plant communities.
- No quantitative data on the impact of changes to fire regimes in hummock grasslands and soil organic layers, particularly upon vertebrate communities, invertebrate communities, and non-vascular plants.
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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