Natural resource management plan for the brockman river
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- 2.1.2 The river, major tributaries and wetlands
- Salinity (mS/cm) Depth of Lake (m) Date Sampled
- 2.1.3 Landforms, geology, soils
- Tenure Number Area km 2 (% of remnant area in brackets)
- Remnant size (ha) Conservation and Other Landuse CALM Reserved* Total** Natural Landuse
- Vegetation complex Pre-clearing Post-clearing Reserved Retained Reserved
- 2.1.5 Native plants and animals
2.1.1 Climate The catchment experiences a typical Mediterranean climate of hot dry summers and cool wet winters. Summer has a range from 33˚C in February to 18˚C in July with a mean average temperature of 32.2˚C. Winter has a range of 18˚C in February to 8.2˚C in July with a mean average temperature of 7.0˚C. Average rainfall for the southern portion is 800mm/yr decreasing to less than 600mm/yr in the northern regions (Bureau of Meteorology, 1998). Most water courses in the catchment flow during the winter months and have reduced or no flow during the summer months. Weather patterns typically have strong easterly to north-easterly winds in the morning and south-westerly in the afternoon during summer with thunderstorms and lightning common. During winter the winds come from the northwest to southwest.
The Brockman River flows south along the western edge of the Darling Plateau through a deeply incised valley to join the Avon River between the Walyunga and Avon Valley National Parks. The Wannamal Lake system to the north, and seasonal streams flowing from the east and west, drain directly into the Brockman River. The Wannamal Lake system is listed as a culturally and ecologically significant wetland (Environment Australia, 2001). Analysis of water quality readings (J. Lane, CALM, pers. Comm.) since 1978 indicate that salinity in the lake is increasing (figure 3). Anecdotal information at the time of settlement in the area during the 1890’s indicates that the water was fresh enough to support vegetable gardens and fruit trees (Buchanan, 1996). Observations made by long time residents of the area suggest that during the early 1950’s the water was relatively fresh and that good clover pastures grew in nearby paddocks that are now bare salt scalds (Pers. Comm. D. Purser). A suite of smaller lakes and wetlands to the west, including Lake Bullingarra, are still fresh. 2. What we have in the Brockman River catchment
Sep-79
Sep-80 Sep-81
Sep-82 Sep-83
Sep-84 Sep-85
Sep-86 Sep-87
Sep-88 Sep-89
Sep-90 Sep-91
Sep-92 Sep-93
Sep-94 Sep-95
Sep-96 Sep-97
Sep-98 Salinity (mS/cm) Depth of Lake (m) Date Sampled - Salinity - Depth
2.2 Water and Rivers Commission Natural Resource Management Plan for the Brockman River Catchment The township of Bindoon is situated on the Brockman River where it flows into Lake Needoonga, part of the Chittering Lake system and a listed significant wetland (Environment Australia, 2001). In 1975, CALM constructed a weir at the end of the Chittering Lakes Nature Reserve to control the levels of Chittering and Needoonga lakes. The gates in the weir regulate the flow of water and the depth of the lakes. The weir was installed after a drain was constructed that caused the lakebed to drain prematurely, impacting on the bird-breeding season. The aim of the water management is to achieve a desirable water level in the lake throughout the year. The lake should be dry from mid-March to the opening rains and the more saline waters that accumulate during mid to late summer should not be released downstream in an uncontrolled manner (P. Dans, pers. Comm.). Thus, during the summer months, only the catchment south of the weir contributes to the water flow in the Brockman River. The water levels in Lake Chittering are managed for: • Wildlife management to sustain the lake vegetation survival and regeneration and the annual bird breeding season; • The farming industry to avoid excessive flooding of adjoining agricultural land, and; • The horticultural industry to avoid releasing excessively saline waters down the Brockman River that adversely impacts the opportunity for farmers to irrigate horticultural crops. Guidelines have been developed to ensure the requirements of conservation, neighbours and downstream users are all considered (CALM, 1999). 2.1.3 Landforms, geology, & soils The Darling Plateau, an ancient landmass worn down by erosion, underlies most of the eastern portion of the Brockman River catchment. To the west, the catchment extends over the Dandaragan Plateau. A major regional fault line, the Darling Fault, separates these two geomorphic regions.
The Darling Plateau is made up of two major rock sequences. The first sequence is a 10-km wide belt of crystalline rocks referred to as the Chittering Metamorphic belt. Intense erosion within the Chittering Metamorphic belt has produced a major north-south trending valley system in which the Brockman River flows south. The second sequence to the east is granitic rock covered with a lateritic cap referred to as the lateritic uplands(Wild and Low, 1978). Laterite is sometimes referred to as ironstone or coffee rock. The deeply incised Chittering Valley is characterised by dissected, steep slopes and domed granite outcrops high in the landscape with variable and complex soils. Parent materials may be weathered or unweathered gneiss, granite or dolerite or may occur as colluvium. Colluvial lateritic material from the plateau surface may extend down slope. Yellow duplex and brown duplex and gradational earths are the most common soils. Generally, the yellower soils are associated with the granite, and the red and brown soils with dolerite dykes (King and Wells, 1990). Loamy soils, now extensively cleared for agriculture, are found on the lower valley slopes and floodplain. The lateritic uplands are typified by undulating, dissected land surfaces with rubbly, pale orange lateritic soils and pea gravels. Red alluvial, clay soils characterise the valley floors while upland remnants of the plateau surface form higher land with sands and sandy gravels interspersed with laterite outcrops. Saline soils occur within the valley floors. Most of the area outside reserves is cleared for agriculture with small pockets of native vegetation along fence lines and watercourses. Gully erosion is the predominate erosion hazard but landslips have occurred on the steeper slopes of the Chittering Valley. The Dandaragan Plateau The Dandaragan Plateau to the west of the Darling Fault is a wedge shaped erosion remnant of the Perth Basin with sediments covered by recent deposits of sand and laterite (Wild and Low, 1978). Sandplain features dominate the landscape with broad U-shaped valleys, sand-filled drainage lines and some breakaways. The soil pattern is closely related to topography (Churchward, 1980). Brown deep sands, yellow deep sands, pale deep sands, sandy gravels and shallow gravels are dominant, with red deep sandy duplex soils on the valley floors (Moore, 1998). Soil landscapes are outlined in the Shire of Chittering Land Capability and Management Study prepared by 2.3 Water and Rivers Commission Natural Resource Management Plan for the Brockman River Catchment Land Assessment Pty. Ltd. Part 1 – Working Paper. A summary appears in Appendix 1.
Field studies of the distribution of vegetation complexes in the Brockman River catchment were completed using existing vegetation maps produced as part of the System 6 study (DEP). The extent and condition of native vegetation in the catchment is shown in figure 4 and summarised in table 1. Native vegetation covers approximately 770 km 2 , or 51% of the total area of the region (1,520 km 2 ). The greatest area of native vegetation occurs within the western forest/woodland and eastern heath regions while the central area consists of severely dissected remnants within an agricultural landscape. These areas have been heavily cleared and now the remaining remnants are generally small and dispersed. Approximately 201 km 2 (13%) is reserved for conservation purposes with much of this conservation land being confined to the eastern Darling Scarp forests and north-western sandplain. The landuse and number of vegetation remnants in the Brockman River catchment is outlined in table 2 and figure 5. Size class of remnants by landuse is shown in table 3. Twenty System 6 vegetation complexes are recognised in the catchment and are shown in figure 6. Figure 7 and table 4 show the remnant vegetation complexes represented now and the spatial extent of vegetation complexes pre and post clearing and currently reserved. One complex (Williams-Avon-Brockman-Mumballup Complex) has less than 20% remaining of its original area, while twelve complexes have less than 10% of their original extent reserved. The complexes that remain best represented occur in the east and northwest, and correspond to the greatest areas of remnant vegetation (Connell and Ebert, 2001). Heddle et al (1980) identified vegetation complexes for each of the soil landform associations defined by CSIRO (Churchward and McArthur, 1978), and are related to the geomorphic units (see appendix 2). Table 1: Spatial extent of remnant vegetation in the Brockman River catchment. Total area (km 2 )
Number of remnants 2,000
Total area of remnant vegetation (km 2 ) 770 % Total remnant area 51% Remnant vegetation reserved (km 2 ) 201 % Original area reserved 13 % Remnant area reserved 26 Source: Connell and Ebert (2001). 2.4 Water and Rivers Commission Natural Resource Management Plan for the Brockman River Catchment
Study area NA 1521
Conservation and Natural Landuse 517*
629 (82%) Other Landuse 5481* 141 (18%) CALM Reserved** 31*
201 (13%) TOTAL 1521
770 (51%) * the comparatively large number of remnants is due to the road/cadastre/landuse intersections process detailed in the methodology.
Number Area (km 2
Number Area (km
2 ) Number Area (km 2 ) Number Area (km 2 ) < 1 ha 324
0.67 3667
9.94 1 0.0 3991 10.61
0 to 10 82 2.77 1542 45.48
1 0.0
1624 48.25
10 to 50 43 10.27 231 48.31
4 0.6
274 58.58
50 to 100 16 11.87 31 21.77
7 2.2
47 33.64
100 to 500 34 67.09 10 15.36
2 1.4
44 82.45
> 500 18 536.49 0 0 16 197.0 18 536.49 TOTAL 517
629.18 5481
140.86 31 201.2 5998 770
Note: Remnant area calculations are based on a remnant vegetation – landuse GIS intersection; hence their numbers may not match Remnant counts in some other tables. * CALM Reserved land is a subset of the Conservation and Natural Landuse category. ** Total Number and Total Area are calculated as the sums of the first two landuse categories. 2.5 Water and Rivers Commission Natural Resource Management Plan for the Brockman River Catchment
No.
Area (ha) No.
Area (ha) No.
Area (ha) (%) (%) Bindoon Complex 3 8900
258 2441
6 191
27.4 2.1**
Cook Complex 14 542 22 416
0 0 76.7 0.0** Coolakin Complex in low rainfall 29 20560 582 9085
20 3270
44.2 15.9
Cullula Complex 1 18977 205 10411
2 826
54.9 4.4**
Darling Scarp Complex 4 80 8 33 0 0 41.7
0.0** Dwellingup & Yalanbee Complex, low - medium rainfall
2 1164
9 1073
4 688
92.2 59.1
Dwellingup,Yalanbee & Hester Complex, low - medium rainfall 5 1535 8 1532
8 1398
99.8 91.1
Helena Complex, low - medium rainfall 1 4358
71 2127
4 90 48.8 2.1** Karamal Complex-South 1 5805
36 4180
2 2704
72.0 46.6
Michibin Complex 5 19342 407 7940
6 1353
41.1 7.0**
Mogumber Complex- North
2 2225
8 1428
0 0 64.2 0.0** Mogumber Complex- South 8
111 1383
0 0 39.0 0.0** Murray & Bindoon Complex, low - medium rainfall
3 12456
299 5424
14 603
43.6 4.8**
Nooning Complex 1 2698 141 553
2 170
20.5 6.3**
Pindalup & Yarragil Complex, low - medium rainfall 11 4934 76 3514
11 1648
71.2 33.4
Reagan Complex# 1 3 3 0.6
0 0 17.6* 0.0 Wannamal Complex 6 2775
85 888
6 41 32.0 1.5** Williams-Avon- Brockman-Mumballup Complex
1 959
82 136
1 2 14.2* 0.2** Yalanbee & Dwellingup Complex, low rainfall 3 16922 153 13714
14 5098
81.0 30.1
Yalanbee Complex in low rainfall 50 24316
804 10730
15 2190
44.1 9.0**
TOTAL 151
152104 3368
77017 115
20272 50.6
13.3 NOTES
# vegetation complex found at the periphery of the catchment * less than 20% of original area remains ** less than 10% of original area reserved
2.6 Water and Rivers Commission Natural Resource Management Plan for the Brockman River Catchment
2.7 Water and Rivers Commission Natural Resource Management Plan for the Brockman River Catchment
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2.8 Water and Rivers Commission Natural Resource Management Plan for the Brockman River Catchment
2.9 Water and Rivers Commission Natural Resource Management Plan for the Brockman River Catchment
2.10 Water and Rivers Commission Natural Resource Management Plan for the Brockman River Catchment
In the Brockman River catchment, continued destruction and fragmentation of habitat through clearing, grazing, land degradation, declining water quality, introduction of exotic species, disease and changes to fire regimes has contributed to declining native plant and animal populations. This decline has caused loss of native species and will lead to other species becoming vulnerable. However, some animals have adapted well to the changed landscape and their numbers continue to increase. These include western grey kangaroos (Macropus fuliginosus), galahs (Cactua roseicapilla), ravens (Corvus coronoides), magpies (Gymnorhina dorsalis), corellas (Cacatua tenuirostris) and the Port Lincoln parrot (Barnardius zonarius) and their numbers continue to increase.
There are 8 species of Declared Rare Flora and 50 Priority Flora within the catchment boundary. Most of these are found on the roadside verges, others are found growing on private property and some are within reserves. This makes them particularly vulnerable to extinction. Included in the rare flora is Grass Wattle (Acacia anomala) and Star Sun Orchid (Thelmytra stellata) (see plate 1) to the south, and to the north, Bindoon Star Bush (Asterolasia nivea), Darwinea acerosa and Spirogardnera rubescens while Eleocharis keigheryi is found near watercourses and wetlands. A list of all plants recorded in the Shire of Chittering are listed in appendix 3, included is a list of the rare and priority flora.
Rare and priority fauna The Western Shield program was initiated by CALM to increase introduced predator control, captive breeding programs and reintroduction of native animals to their former habitat. Fox control using “1080” poison and fauna re-introductions, have been ongoing in Julimar State Forest since 1993. Native species reintroduced are chuditch (Dasyurus geoffroyii), quenda (Isooden obesulus fusciventor), woylies (Bettongia penicilliata), tammar wallaby (Macropus eugenii) and brush-tailed possum (Trichosurus vulpecula). These native animals are still vulnerable and in need of protection. The critically endangered western swamp tortoise (Pseudemydura umbrina) (see plate 2) has also been released in the north of the catchment at Mogumber. Winter wet clay depressions in the area provide suitable habitat in which twenty tortoises were released in an attempt to establish a wild population. Fox control in the reserves and on surrounding properties is vital for their survival and the population is closely monitored by CALM (table 5).
Loss of native vegetation on which most land birds in the southwest of Western Australia (83%) depend for all or part of their annual requirements (Smith 1987) will inevitably result in significant changes to populations and possible species loss. Populations of species such as the Carnaby’s cockatoo (Calyptorhynchus funereus latirostris) have been much reduced through habitat loss (Saunders and Ingram, 1987).
Bird species recorded in the Julimar State Forest that are at or near the northern limit of their distributions include the rufous tree creeper (Climacteris rufa) and the splendid fairy wren (Malaurus splendens). Bush birds found within the catchment are typical of the jarrah-marri woodland and the wandoo woodland habitats (Department of Defence, 1998). One hundred and twenty nine species of bird have been recorded from the Wannamal area (Buchanan, 1997) including the Carnaby’s Black Cockatoo (Calyptorhynchus latirostris). Wannamal birds have been studied on behalf of CALM and other authorities for some years. The first report included Lake Wannamal and surveys have been kept up for both water birds and bush birds since, though not continuously. The Wannamal Lake system forms the headwaters of the Brockman River and is a major breeding and drought refuge area for waterbirds. Fifty-two species of water birds have been recorded in the system, seven listed under treaties. Freckled duck (Stictonetta naevosa) occurs regularly in the system. The Mogumber Swamp is one of the few wetlands in south-western Australia in which Australian crake (Porzana fluminea) is known to breed regularly in low sedges mixed with low shrubs. Other species for which the Wannamal Lake is regionally significant are Australasian grebe 2.11 Water and Rivers Commission Natural Resource Management Plan for the Brockman River Catchment (Tachybaptus novaehollandiae), hardhead (Aytha australis) and black-tailed native-hen (Gallinula ventralis). Wannamal Lake is included on the Register of the National Estate (Environment Australia, 2001). The Chittering-Needoonga Lakes are part of the Brockman River and are a major breeding area for water birds. Forty-two species have been recorded, four listed under treaties. The Lakes are a major breeding place for the great egret (Egretta alba) and the rufous night heron (Nycticorax caledonicus) in Western Australia. Freckled duck (Stictonetta naevosa) occurs regularly with vegetation and the spring water levels in the lakes making the site suitable for breeding. Other breeding colonies in Lake Needoonga include the Australian white ibis (Threskiornis molucca), yellow- billed spoonbill (Platalea flavipes) and little pied cormorant (Phalacrocorax melanoleucos). The site is regionally significant for Australasian grebe (Tachybaptus novaehollandiae), great egret (Egretta and alba), yellow-billed spoonbill (Platealea flavipes), maned duck (Chenonetta jubata) (Environment Australia, 2001). Both of these wetland systems are under threat from increasing salinity, siltation and eutrophication. The Wannamal wetland system is also under threat from excessive inundation causing the death of wetland trees. Kataloq: data -> assets -> pdf file -> 0004 pdf file -> References: Jackson, N. O., and Pawar, S. (2013). A demographic Accounting Model for New Zealand. Nga Tangata Oho Mairangi: Regional Impacts of Demographic and Economic Change – 2013-2014. Mbie-funded project pdf file -> A worker’s response to stressors at work may be positive or negative for worker wellbeing, depending on a number of pdf file -> Transurethral Prostatectomy (turp) & Open pdf file -> Department of General Practice Newsletter pdf file -> Wild radish (Raphanus raphanistrum) pdf file -> Collaboration Analysis of research performance through a gender lens 0004 -> Beach Cherry Description 0004 -> Key for Symbols attracts lizards Yüklə 2 Mb. Dostları ilə paylaş:
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