MacDonnell Ranges bioregion

Description Figure 2 Monitoring sites and pastoral tenure Area: 39 290 km2

The MacDonnell Ranges bioregion is characterised by high-relief ranges and foothills. Spinifex and acacias, particularly mulga, occur throughout the bioregion. Land tenure is pastoral leasehold, conservation reserve MacDonnell and Aboriginal freehold. The main industries are cattle Ranges P3 grazing and tourism. is the major sub-IBRA population centre. bioregion boundary pastoral tenure Location Tier 1 monitoring site The MacDonnell Ranges bioregion is located in the Data sources available southern (NT; see Figures 1 and 2). Monitoring sites and pastoral tenure Data sources include: Figure 1 Location of the MacDonnell n NT Tier 1 — low reliability for reporting change, Ranges bioregion with a small number of sites on the northern and southern edges of the MacDonnell Ranges P3 sub-Interim Biogeographic Regionalisation for (IBRA); estimated (rather than quantitative) data; and a focus on perennial herbage species

n domestic stocking density, which provides moderate reliability

n fire extent, intensity and frequency, which provides high reliability

n dust

n distance from water

n distribution and relative abundance of invasive animals and weeds Location of MacDonnell Ranges bioregion n land use.

MacDonnell Ranges bioregion 1 Climate Percentage of reassessed sites showing: The MacDonnell Ranges bioregion has an arid climate, Decline: Increase: which is modified to some extent by mountain ranges. > 20% > 20% Rainfall is summer dominant, and spatially averaged decrease increase median (1890–2005) rainfall is 228 mm (April to Seasonal Number in 2P No in 2P March rainfall year; see Figure 3). quality of sites grasses change grasses Above Figure 3 Decile rainfall for the period average 16 6% 88% 6% 1991–1992 to 2004–2005 Average 3 n/a n/a n/a Below 10 9 average n/a n/a n/a n/a 8 7 6 median 5 Plant species richness 4 3 There are no suitable data for reporting change

Rainfall decile 2 in plant species richness. 1 0 1991-92 1993-94 1995-96 1997-98 1999-00 2001-02 2003-04 Change in woody cover Rainfall year Based on the Australian Greenhouse Office definition Annual rainfall is for the 12‑month period 1 April and mapping of forest extent1, there are no significant to 31 March. areas of forest in the MacDonnell Ranges bioregion. There was widespread coverage of Landsat data in The 1992–2005 reporting period was characterised by making this assessment. considerable variation in rainfall. The year 1991–1992 was exceptionally dry and the 1999–2000 to Distance from stock water 2001–2002 period was very wet. Based on the locations of stock waterpoints sourced Note that regional averaging of rainfall conceals spatial from NT government mapping of lease infrastructure, variability. Some parts of the MacDonnell Ranges the percentage area of pastoral lease country within bioregion may have experienced better seasonal three kilometres of permanent and semipermanent quality and others worse during the 1992–2005 period. sources of stock water for each sub-IBRA is:

MacDonnell Ranges P1 63.0% (17.2% of Landscape function (MAC1) sub-IBRA analysed) There are no suitable data for reporting change in MacDonnell Ranges P2 33.5% (26.7% of (MAC2) sub-IBRA analysed) landscape function. MacDonnell Ranges P3 69.4% (46.5% of (MAC3) sub-IBRA analysed) Sustainable management IBRA = Interim Biogeographic Regionalisation for Australia; MAC = MacDonnell Ranges

Critical stock forage (MacDonnell Note that this analysis does not include the locations Ranges P3 sub-IBRA) of natural waters. The MacDonnell Ranges has many Approximately 6% of sites showed a decline in semipermanent natural waters (rock holes, springs composition (by biomass) of palatable perennial etc). These are generally inaccessible to controlled (2P) herbage species when seasonal quality was (managed) cattle but are often a haven for feral above average. It is not possible to report change animals (wild cattle, brumbies and donkeys). following below-average seasonal quality.

1 See http://www.greenhouse.gov.au/ncas/reports/tech09.html

2 Rangelands 2008 — Taking the Pulse It is not possible to report change in watered area Invasive animals for the 1992–2005 period. Invasive animal species known to occur in the Weeds MacDonnell Ranges bioregion include: Weeds known to occur in the MacDonnell Ranges Common name Scientific name bioregion include: Feral pig Sus scrofa Fox Vulpes vulpes Common name Scientific name Rabbit Oryctolagus cuniculus African love grass Eragrostis curvula Wild dog Canis spp. Athel pine Tamarix aphylla Feral cat Felis cattus Bathurst burr Xanthium spinosum Camel Camelus dromedaries Lippia Phyla canescens Donkey Equus asinus Mesquite Prosopis spp. Horse Equus caballus Mexican poppy Argemone ochroleuca See www.anra.gov.au for distribution maps Mission grass Pennisetum polystachion Noogoora burr Xanthium occidentale Parkinsonia Parkinsonia aculeata Products that support reporting Sida spp. Sida spp. of landscape function and See www.anra.gov.au for distribution maps sustainable management

Components of total Fire grazing pressure A small area of the MacDonnell Ranges bioregion burnt in 2001, extending to a considerable area in Domestic stocking density 2002 following wetter years. Fire was nonexistent or negligible at other times between 1997 and 2005. Approximately 62% of the MacDonnell Ranges Most of the fires in the 2001–2002 period occurred bioregion is within pastoral leases. Much of this between April and November and were likely less country is mountainous, is difficult to manage and intense than summer fires. has low pastoral value.

Data from the Australian Bureau of Statistics are too Year sparse to report change in stocking density reliably. 1997 1998 1999 2000 2001 2002 2003 2004 2005 % area burnt 0.0 0.0 0.0 0.2 4.6 20.4 0.4 0.0 0.0 Kangaroos There are no suitable data for reporting change The frequency of fire during the reporting period in kangaroo density. was low compared with other rangeland bioregions,

with a mean frequency (log10 transformed) of 0.01.

Dust Dust data report for the whole bioregion. The mean Dust Storm Index value (1992–2005) was 2.90, which is a moderate value compared with all rangeland bioregions. Dust levels were slightly higher in the centre of the bioregion and lower to the east and west.

MacDonnell Ranges bioregion 3 Biodiversity Socioeconomic characteristics

By 2005, there were more than 200 bird species and Land use and value more than 100 reptile species recorded in this bioregion (Biodiversity Working Group indicator: Fauna surveys; Approximately 62% of the MacDonnell Ranges see Section 7 of Chapter 3 of Rangelands 2008 — bioregion is pastoral leasehold. This area has not changed Taking the Pulse). There were approximately 1500 appreciably over the 1992–2005 reporting period. plant taxa recorded (Biodiversity Working Group indicator: Flora surveys). Key management issues A case study (see Buffel grass, Transformer weeds, and features Chapter 3) exists on how buffel grass transforms habitats in the bioregion (Biodiversity Working Group Key features and issues of the MacDonnell Ranges indicator: Transformer species). bioregion include the following:

In the MacDonnell Ranges bioregion, there are n The MacDonnell Ranges bioregion contains the (Biodiversity Working Group indicator: Threatened highest number of vulnerable or rare species species): listed with conservation status nationally and at the NT level. n 11 threatened plant species n Recent intense fires in the eastern part of the n 16 threatened mammal species (including bioregion have removed perennial grass and 6 extinct species) shrub layers, and recovery to date from these n 6 threatened bird species has remained patchy. n 2 threatened reptile species n Coordinated programs to control feral animals are implemented opportunistically on, and adjacent n 3 threatened invertebrate species. to, conservation areas and reserves. These programs may involve neighbouring pastoral lessees, but generally, these control efforts have not extended far into pastoral lands.

4 Rangelands 2008 — Taking the Pulse