Brigalow Belt South bioregion

Description Figure 2 Rangeland Assessment Program monitoring sites (NSW) and Area: 56 496 km2 data from the Rapid Mobile The Brigalow Belt South bioregion contains mixed Data Collection (Queensland) landscapes, including undulating to hilly areas with low QLD ridges and deep valleys, as well as flat alluvial plains in the south. There is a large distance between the extreme southern sections in northern New South Wales (NSW) and those parts in rangeland Queensland. Vegetation is predominantly mixed eucalypt woodland with areas of brigalow scrubs and open Mitchell grasslands. Tenure is mostly leasehold, with cattle bioregion boundary RMDC grazing being the major land use. Relatively small AussieGRASS data outliers of the bioregion occur in northern NSW. RAP monitoring site NSW The only major population centre within the defined boundaries is Mitchell. Data sources available Data are collected from the Queensland section of Location the bioregion using the following:

The Brigalow Belt South bioregion is located in n Rapid Mobile Data Collection (RMDC) supported southern Queensland with a small area (6.5%) by AussieGRASS simulation (to measure pasture in northern NSW (see Figures 1 and 2). growth and utilisation)

Figure 1 Location of the Brigalow n remote sensing (using the Multiple Regression Belt South bioregion Bare Ground Index, version bi1). Reliability in reporting:

n RMDC data have moderate reliability for reporting change in landscape function (visual estimates made along road traverses, data broadly describe landscape function)

n AussieGRASS simulation covers all the rangelands; modelled results are validated with some ground truthing. In NSW, data are collected at Rangeland Assessment Program (RAP) sites. There is a low to moderate reliability for reporting change, because of the small number (four) of sites across part of the bioregion. Annual assessments are made. Data are quantitative, Location of Brigalow Belt South bioregion and there is a focus on perennial species.

Brigalow Belt South bioregion 1 Other datasets for the whole bioregion include: Landscape function n domestic stocking density, which provides moderate reliability for reporting change Queensland n fire extent, intensity and frequency, which Visually assessed vegetation and soil attribute data provides high reliability collected along road traverses with the RMDC method n dust The Claude River Downs and Southern Downs sub-Interim Biogeographic Regionalisation for n distance from water Australia (IBRA) showed some loss of function. n distribution and relative abundance of invasive The Carnarvon Ranges sub-IBRA is considered stable. animals and weeds Buckland Basalts sub-IBRA was not adequately assessed n land use with the RMDC method. AussieGRASS simulation suggests no change in landscape function for this area. n land values. New South Wales Climate RAP, index based on the frequency and cover The Brigalow Belt South bioregion has a hot to of perennial herbage species warm subhumid climate with summer-dominant Only four sites were assessed, which is insufficient rainfall. Spatially averaged median (1890–2005) rainfall for reporting change reliably. is 489 mm (April to March rainfall year; see Figure 3).

Figure 3 Decile rainfall for the period Sustainable management 1991–1992 to 2004–2005 10 Critical stock forage 9 8 7 Queensland 6 median 5 4 AussieGRASS, levels of simulated pasture 3 utilisation and change

Rainfall decile 2 1 0 This data related to the period 1976–1990 1991-92 1993-94 1995-96 1997-98 1999-00 2001-02 2003-04 compared with 1991–2005. Rainfall year All sub-IBRAs apart from Narrandool had simulated Annual rainfall is for the 12‑month period 1 April space- and time-averaged pasture utilisation below the to 31 March. safe threshold for the Brigalow Belt South bioregion during the 1991–2005 period (Narrandool was just Decile rainfall was highly variable throughout the above the threshold). Relative levels of utilisation reporting period. The years 1996–1997 and 1998–1999 increased by about one-third (approximately 7% in to 2000–2001 were very wet. The year 2002–2003 absolute terms) between 1976–1990 and 1991–2005 was extremely dry, while early years (1991–1992, for three sub-IBRAs (Claude River Downs, Buckland 1992–1993 and 1994–1995), then 2001–2002 and Basalts and Carnarvon Ranges). Utilisation levels, on 2004–2005, had rainfall considerably below the median. average, remained stable in the Southern Downs sub- Note that regional averaging of rainfall conceals IBRA and decreased by 8% (3% in absolute terms) spatial variability. Some parts of the Brigalow Belt in the Narrandool sub-IBRA. Spatial and temporal South bioregion probably experienced better seasonal averaging may disguise times and areas with much quality and others worse during the 1992–2005 period. higher utilisation.

2 Rangelands 2008 — Taking the Pulse New South Wales 20% crown cover or more (eg woodlands, open forests and closed forests) and taller than about two RAP, frequency of selected palatable and perennial metres. The annualised rate of clearing represents grasses the annual rate of woody vegetation change, which Only four sites were assessed, which is insufficient is largely due to cropping, pasture and thinning for reporting change reliably. (DNR 2007). At this stage, it is not possible to report change for Plant species richness earlier years of the 1992–2005 period using this method. NSW reporting is based on the count of native perennial and annual herbage species from RAP sites. Distance from stock water Based on the locations of stock waterpoints sourced There were insufficient data for reporting change reliably. from Geoscience Australia’s GEODATA TOPO 250K Change in woody cover vector product (Series 3, June 2006), the percentage area within three kilometres of permanent and semi- Queensland permanent sources of stock water for each sub-IBRA is:

Statewide Landcover and Trees Study (SLATS) Claude River Downs (BBS1) 55.1% reporting showed that two of the Brigalow Belt South Buckland Basalts (BBS9) 9.1% sub-IBRAs (Carnarvon Ranges and Buckland Basalts) Carnarvon Ranges (BBS10) 28.8% are characterised by high woody cover. There was Southern Downs (BBS12) 59.2% relatively little change in woody cover (less than 4% Moonie–Barwon Interfluve (BBS20) 73.9% decrease) between 1991 and 2003 in both these Narrandool (BBS28) 86.8% regions. By comparison, there were relatively large BBS = Brigalow Belt South reductions (approximately 10%) in woody cover (due Note: complete sub-IBRA area was analysed mainly to clearing) in the Claude River Downs and Southern Downs sub-IBRAs over the same period. Note that this analysis does not include the locations There is high reliability for reporting change in woody of natural waters, which may provide additional sources cover based on SLATS. of water for stock, particularly following good rains. It is not possible to report change in watered area SLATS woody cover Change for the 1992–2005 period for either jurisdiction. 1991 to Sub-IBRA 1991 2003 2003 Claude River Weeds Downs 65.47% 55.53% –9.94% Weeds known to occur in the Brigalow Belt South Southern bioregion include: Downs 48.16% 39.11% –9.05% Carnarvon Common name Scientific name Ranges 88.16% 85.09% –3.07% Athel pine Tamarix aphylla Buckland Mesquite Prosopis spp. Basalts 94.29% 93.57% –0.72% Parkinsonia Parkinsonia aculeata IBRA = Interim Biogeographic Regionalisation for Australia; Parthenium weed Parthenium hysterophorus SLATS = Statewide Landcover and Trees Study Prickly acacia Acacia nilotica subsp. indica New South Wales See www.anra.gov.au for distribution maps SLATS-type reporting showed that the annualised rate of woody vegetation change between 2004 and 2006 was 843 hectares, based on analysis of satellite data using Queensland SLATS methods. Woody vegetation is defined as woody communities with

Brigalow Belt South bioregion 3 Components of total Figure 4 Kangaroo density, NSW grazing pressure Brigalow Belt South bioregion 180 160 Domestic stocking density 140 (reporting for the whole bioregion) 120 100 Approximately 80% of the Brigalow Belt South 80 bioregion is grazed. Data from the Australian Bureau 60 40 of Statistics showed that the 1992 stocking density was Relative density 20 12% above the average for the 1983–1991 period. 199219931994199519961997199819992000200120022003 (cf 1984–1991 average ) This density decreased to 3% below the base in 1994, gradually increased to 6% above the base in 1998 and 1999, increased more sharply to 15% above the base Invasive animals in 2000 and then declined to 13% below the 1983– Invasive animal species known to occur in the 1991 average in 2003. The 2004 stocking density was Brigalow Belt South bioregion include: 92% of the base period. The increase to 2000 reflected some better seasons in the late 1990s, as did the Common name Scientific name decline with poorer seasonal quality between 2001 Feral pig Sus scrofa and 2003. Note that spatial averaging conceals likely Feral goat Capri hircus variation in stocking density trends across the bioregion. Fox Vulpes vulpes Rabbit Oryctolagus cuniculus Kangaroos Wild dog Canis spp. There is insufficient data coverage to reliably report Feral cat Felis cattus for the Queensland Brigalow Belt South. Carp Cyprinus carpio

The combined density of kangaroo species (on a dry See www.anra.gov.au for distribution maps sheep equivalent basis) in the NSW Brigalow Belt South initially declined (1993 to 1996) then increased to Products that support reporting 1998. Kangaroo density fluctuated around this level for five years and then decreased sharply in 2003 of landscape function and (the last year of available data). Changes are shown sustainable management relative to the average density for the 1984–1991 period (see Figure 4). The contributing species to kangaroo Fire density are reds, and western and eastern greys. For the whole bioregion, fire was insignificant in Some wetter years in the late 1990s probably most years, with a maximum of 3.5% of the bioregion contributed to the increasing kangaroo density at burnt in 2004. this time. The large decrease in 2003 lagged rapidly deteriorating seasonal quality by a year or so. Dust Dust data report for the whole bioregion. The mean Dust Storm Index value (1992–2005) was 0.90, which was among the lowest of values for all rangeland bioregions. Dust levels were low in the southeastern part of the Queensland Brigalow Belt South and negligible elsewhere.

4 Rangelands 2008 — Taking the Pulse Biodiversity In NSW, the market value of a typical property in the Lightning Ridge area increased by approximately For the Queensland portion of the bioregion, there 50% between 1996 and 2005 (values expressed in are (Biodiversity Working Group indicator: Threatened 2005 dollars). Average property size is 783 hectares species; see Section 7 of Chapter 3 of Rangelands 2008 (maximum size of 6900 hectares) for all land parcels — Taking the Pulse): bigger than 10 hectares. n 61 threatened plant species (includes 1 extinct species, Amphibromus whitei) Key management issues n 13 threatened mammal species (includes 2 and features extinct species, the white-footed rabbit-rat and the Darling Downs hopping-mouse) Key issues and features of the Brigalow Belt South bioregion include the following: n 11 threatened bird species (includes 1 extinct species, the paradise parrot) n Queensland: n 9 threatened reptile species – increasing Parthenium weed n 1 threatened amphibian species – areas of high pasture utilisation n no threatened fish species. – understorey species change (eg buffel grass or unpalatable perennials) There have been relatively more fauna surveys conducted in this bioregion compared with other – areas of woody regrowth following partially Queensland rangeland bioregions (Biodiversity successful clearing Working Group indicator: Fauna surveys). – fire management of cypress pine forests and associated controls on grazing by domestic stock.

Socioeconomic characteristics n NSW:

Land use and value – low returns from wool have led to increased cropping where possible Approximately 80% of the Brigalow Belt South bioregion is grazed. This area has not changed – the low value of sheep in the early 1990s appreciably over the 1992–2005 reporting period. coupled with drought in 1992 resulted in high grazing pressure and adverse impact In Queensland, the unimproved rangeland values as at on land condition in some areas June 2006 were, on average, $17 780 ± $2046/km2 – goats have also had an adverse impact on (value expressed in 2005 dollars). There was a large the condition of some areas; their increased range in average unimproved value across sub-IBRAs meat value in recent times means that they ($3293 to $21 182/km2). It is not possible to report are harvested to supplement income. change in land values for the 1992–2005 period.

Brigalow Belt South bioregion 5