Biodiversity Assessment - Tanami
Tanami
Introduction
The Tanami bioregion comprises mainly red Quaternary sandplains overlying Permian and Proterozoic strata which are exposed locally as hills and ranges. The sandplains support mixed shrub steppes of Hakea suberea, desert bloodwoods, acacias and grevilleas over Triodia pungens hummock grasslands. Acacia shrublands over hummock grass communities occur on the ranges. Alluvial and lacustrine calcareous deposits occur throughout. In the north they are associated with Sturt Creek drainage, and support Chrysopogon and Iseilema short-grasslands often as savannas with River Gum. The climate is arid tropical with summer rain. The Tanami bioregion is divided into three subregions.
Summary of overall condition and trend
Most of the bioregion is generally in good condition, with little intensive use. However, feral predators (foxes, cats) and other factors have caused the regional extinction of 13 mammal species (including central rock-rat and mala), and the decline of many other mammals. Fire regimes have changed substantially over the last century, following less intricate Aboriginal management over large areas, leading to broad-scale detriment in many vegetation communities. Some weeds are also increasing, with at least localised impacts of buffel grass and Parkinsonia. The three subregions are continental landscape stress class 5 as assessed by the Landscape Health report (1 is most stressed, 6 is least stressed).
Summary of conservation priorities
There are three main priorities for natural resource management in the Tanami: (1) remedial actions (e.g. exclosure fencing) in some pastoral lands largely on the periphery of the region (most notably in the wetland system of Sturt Creek); (2) resources and capacity building for Aboriginal land owners to become more effective managers of NRM (mostly fire, weeds and ferals) problems over the extensive areas of Aboriginal lands; and (3) development and ongoing support for Indigeonous Protected Areas or other cooperatively managed conservation areas.
Natural values
The Tanami bioregion comprises large areas of desert communities little affected by intensive development and at least superficially in good condition. The sandplains support threatened species including bilby, marsupial mole and mulgara. There are also impermanent but significant wetland systems.
Click here to link to a table of natural values within each subregion
Wetlands
The bioregion includes two nationally significant wetlands: Lake Surprise (Yinapaka) (NT019: wetland type A6) and the Lake Gregory system (WA096: wetland types B7, B8 and B2). Parts of the Lake Gregory system have been degraded by livestock, but management may be expected to improve as the area has recently been included within the large (4,346 km2) Paruku Indigenous Protected Area.
The bioregion also contains many smaller ephemeral wetlands and watercourses, which are intermittently of at least regional significance.
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 largest river system in the bioregion is Sturt Creek (which flows into Lake Gregory). Other ephemeral watercourses include the Lander and Hanson Rivers and Winnecke Creek. Condition is generally good, although there are at least localised impacts from feral animals and livestock, and from weeds.
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
There has been no formal assessment of the conservation status of ecosystems across most of the bioregion. At least parts of some wetland communities (e.g. Lake Wilson, Lake Gregory) have been degraded by livestock and/or feral animals. Changed fire regimes have led to floristic changes and/or demographic changes for some plant species in many communities across much of the bioregion.
Table: 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.
There is no data available for this table within the bioregion.
Table: Provisional list of threatened ecosystems in each subregion: their threatening processes
There is no data available for this table within the bioregion.
Table: Provisional list of threatened ecosystems in each subregion: their recommended recovery actions
There is no data available for this table within the bioregion.
Species at risk
Ten species still occurring in this bioregion are listed as threatened at Commonwealth or State/Territory level.
Number of taxa in the Tanami bioregion listed as threatened at national and/or NT/WA level (nb this table includes only species definitely recorded from the bioregion (rather than putative occurrences based on modelling) and presumed to be still extant in the bioregion).
| Taxa | Commonwealth | Northern Territory | ||
|---|---|---|---|---|
| Endangered | Vulnerable | Endangered | Vulnerable | |
| plants | 0 | 0 | 0 | 1 |
| reptiles | 0 | 1 | 0 | 1 |
| birds | 0 | 3 | 0 | 3 |
| mammals | 1 | 3 | 0 | 4 |
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
Endemism
There are no endemic eucalypt species and three endemic acacia species in this bioregion: Acacia abbreviata, A. crassifructa and A. sp. (Tanami A91044), all from subregion 1. There is little information about the status of these species, but all are likely to have been detrimentally affected by changed fire regimes.
Richness
Tanami 1 subregion is rich for Acacia (76 species), and moderately rich for Eucalyptus (33 species). Reflecting their smaller size and less intensive collecting, the two other subregions have low to moderate richness of Acacia (26 and 31 species) and Eucalyptus (19 and 19 species).
Birds
Many birds of the northern and western semi-arid zone are widespread, with few restricted range or threatened species. Of these, only the Princess Parrot has been recorded in the Tanami, and then only once. Nor is the bioregion a favourable environment for introduced species. Although no trends were found among guilds, the number of records of Australian residents, and some species has increased greatly. This is true for some of the more mobile inland waterfowl, which may have responded to the higher rainfall in the second Atlas period, and some bush birds including doves and many honeyeaters, which may have responded to the same cues.
Status: Typical semi-arid avifauna, no distinctive features.
Rare and threatened: No major populations.
Increasers: No species likely to be indicative of long-term change.
Indicators: Emu, Australian Bustard, Jacky Winter.
Trend: Probably no change outside normal climatic fluctuations.
Scenario: Little change.
Actions: None pressing.
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 49 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 .531. (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 .33. (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 .37. (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 .65. (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 .74. (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 10. (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 13. (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
Notwithstanding the important recent establishment of an Indigenous Protected Area around Lake Gregory, the existing reserve system in this bioregion is meagre and far from comprehensive. Enhancement of this system is a priority, especially in the far eastern part (subregion 3) and in the central Tanami Desert itself.
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
There is little existing NRM specifically for threatened species or ecosystem recovery. Notable exceptions are some exclosure fencing to allow recovery of riparian/wetland areas (Birrindudu and Lake Gregory area), and a long-running but now defunct enclosure and protective management for mala at Sangster's Bore in the Tanami Desert. Enhancement of the Indigenous Protected Area system and agreements on pastoral stations may provide scope for additional similar intensive management actions for threatened species and susceptible ecosystems.
Integrated NRM
The major NRM issues in the bioregion relate to pervasive insidious threatening processes (weeds, feral animals, changed fire regimes), whose management requires additional resources and support, capacity building among landowners, and better integration across tenures and jurisdictions. There has been some improvement in this management in recent years, through the Central Land Council's land management units, the development of the IPA process and broad-scale monitoring and management of fire by the Bushfires Council (in the NT), however the resources currently available are insufficient to check these processes across this vast and poorly accessed region.
Map: IBRA map showing frequency of recovery actions (species).
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
Most of the large NT portion of subregion 1 has been sampled comprehensively for vertebrates, although this work is now more than 15 years old. There has been far less systematic sampling for fauna in the WA portion of in the two other subregions, and very little systematic floristic sampling.
Management would also benefit from more detailed environmental mapping, in particular vegetation mapping at the scale of 1:250,000 or better.
Currently in this bioregion, there is no substantial monitoring program which includes as a major goal the assessment of trends in biodiversity conservation, or in the extent and impacts of threatening processes (with the exception of some mapping of fire regimes and irregular aerial surveys of feral animals). Such a program should be a management priority.
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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