Fitzgerald biosphere recovery plan



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2.2 Fitzgerald Biosphere Reserve


In 1954 the present Fitzgerald River National Park (FRNP) was classified as a ‘C’ class reserve for the conservation of flora and fauna, then upgraded to a ‘A’ class National Park in 1973 following the threat of potential mining operations (Jenkins 1980; Newbey & Chapman 1995).
In 1978 the FRNP was designated as one of 12 Australian biosphere reserves because of its relatively pristine state and high biological diversity, especially its flora (Sanders 1997). Since the 1980’s the MAB’s biosphere objectives have been applied to a wider area of approximately 1.3 million hectares which also includes the catchments surrounding the National Park (Watson & Sanders 1997), including part of the Pallinup River catchment and all of the Bremer, Gairdner, Fitzgerald, Hamersley, West, Phillips, Steere and Jerdacuttup River catchments. The National Park (329,000 hectares) is the formal core area of the Biosphere, but is surrounded by a buffer zone consisting of about 130,000 hectares of vegetated reserves, privately owned remnant vegetation, and extended corridors along the coast and up the adjoining river systems (Robinson 1997). This ‘zone of cooperation’ includes the upper catchments of all the river systems that pass through or around the core area. This zone (895,000 hectares) is primarily privately owned and modified farmland containing substantial areas of remnant vegetation.
For the purpose of this plan, the term ‘Fitzgerald Biosphere’ or ‘Biosphere’ refers to the formal core area (FRNP) as recognised by MAB together with the nominal extended buffer and transition zones. This wider concept of the Fitzgerald Biosphere is also used by South Coast NRM Inc. and Fitzgerald Biosphere Group (Figure ). While the boundary that pertains to this plan will remain static, it should be recognised that the notional biosphere boundary may need to allow for the evolution of landcare and ‘social’ catchment groups (Watson & Sanders 1997) and may change through formalisation of any expansion.

2.3 Biodiversity of the Fitzgerald Biosphere


The Fitzgerald Biosphere is internationally and nationally recognised for its high biodiversity richness, species endemism and high level of threats, as it is part of the international Southwest Biodiversity Hotspot (Myers et al. 2000) and includes the National Biodiversity Hotspot ‘Fitzgerald River Ravensthorpe’.
The Fitzgerald Biosphere includes a great complexity of geology and associated soils and vegetation communities. It has a Mediterranean climate with cool wet winters and hot dry summers. The average annual rainfall varies from 360 mm in the north to over 600 mm in the south west coast. The landscape units of the biosphere are explained below in Section 2.
The Biosphere is particularly significant for its plant diversity with over 2500 described vascular flora species, over 100 of which are endemic to the Biosphere. The FRNP and Ravensthorpe Range are floristic hotspots within this area.
As with most Mediterranean areas, the diversity of vertebrate taxa in the Fitzgerald Biosphere is not as rich as its flora diversity, with 29 mammal, 51 reptiles, 14 frogs and 209 bird species (DEC 2009). However, FRNP supports more vertebrate species than any other conservation reserve in south-western Australia. The FRNP is at a faunal crossroads in a north-south and east-west direction and includes both arid and mesic adapted species (Chapman et al. 1995). Only one vertebrate species, the skink (Lerista viduata), is endemic to the Biosphere.
Little is known about other components of the Fitzgerald Biosphere biodiversity, such as invertebrates and fungi. As part of a south coast inventory survey for fungi and short-range endemic invertebrates in 2006/07, 181 species of fungi (Syme 2008) and over 70 species of terrestrial invertebrates (Framenau et al. 2008; Harvey & Leng 2008) were recorded in the Biosphere. However, these surveys were not extensive and there remains much to be learnt about the biodiversity of the Biosphere.
The Fitzgerald Biosphere retains just over half (51%) of its native (or remnant) vegetation. The most regionally significant areas are:

  • Fitzgerald River National Park,

  • Ravensthorpe Range and its link between FRNP and Southern Goldfields,

  • Coastal reserve system between FRNP and Pallinup River (which continues further west towards Albany),

  • Lake Magenta Nature Reserve and the Fitzgerald River corridor link to FRNP,

  • Corackerup/Peniup area and its links to Pallinup River,

  • Jerdacuttup Lakes Nature Reserve.

(RAP 1997; Watson & Wilkins 1999)

2.4 Landscape Units of the Fitzgerald Biosphere


The Fitzgerald Biosphere represents a wide range of ecosystems with different physical characteristics and biodiversity. These diverse ecosystems respond differently to threatening processes and management practices, although these differences are in general poorly understood. It is therefore useful to divide the region into units with common denominators that can be used to help interpret complex natural systems where information is incomplete.
In 2004 Nathan McQuoid, a local ecologist, developed the concept of ‘ecozones’ for the south coast of Western Australia, dividing the region into ecozones based on similarities in physical and biological patterns of geology, climatic history, drainage patterns, major soil systems, and existing native vegetation types (McQuoid 2004). These ecozones (referred to in this Plan as Landscape Units) have been refined by Nathan McQuoid in 2009 for the Fitzgerald Biosphere (Table , Figure ). They contextualise the physiographical patterning of the Biospheres ecosystems and vegetation communities, and address the foundations for the presence of the biota, its distribution patterns and the physical forces that support its existence.
Further details on the Landscape Units can be found in McQuoid (in prep.), Barrett et al. (2009) and McQuoid (2004).
Table : The characteristics of the Landscape Units of the Fitzgerald Biosphere as described by Nathan McQuoid in 2009 and percentage (%) of the Biosphere each unit represents. These landscape units are shown in figure 3.

Landscape Units

Landscape Units Characteristics

% of Area / Distribution

Albany Fraser Coastal

The coastal granite features of the Bremer peninsulas with granite rock vegetation communities, kwongan heath, and fringing mallee and banksia shrublands. This unit contains many vegetation communities and taxa that are endemic, localized or restricted.

0.3% / coastal

Depositional Dynamic

The most recently formed landscape units including drainage lines, flood plains, wetlands, coastal dunes, swales and estuary edges. The most dynamic landscape units with common ground disturbance from water movement and nutrient deposition, where vegetation communities are relatively resilient to more frequent disturbances. These systems are prone to weed invasion due to their disturbance disposition.

18.0%

/ coastal, drainage lines



Depositional Eocene

Valley floor depositional spongolite and clay soil systems. A relatively dynamic landscape unit, although less than Depositional Dynamic, with mallet and moort woodland vegetation systems somewhat resilient to disturbances.

4.1%

/ drainage lines



Esperance Sandplain

Mallee and banksia shrubland dominate with interspersed kwongan heath on sand, sandy gravel and sandy clay plains, shallow wetland palusplains, and saline and freshwater lake systems.

5.0%

/ southeast corner



Estuary

Dynamic aquatic systems with fringing chenopod low shrubs on saltpans.

0.2%

Greenstone

The Ravensthorpe Range and nearby associated hills. Is a hotspot for plant diversity with high level of endemism. Primarily mallee and proteaceous heath communities on gravel and sandy gravel soils with down-slope woodlands of mallet on depositional soils. It contains intense mineralization and as such is subject to exploration and mining activity.

3.3%

/ Ravensthorpe Range



Marine Plain

Overlaying Eocene sediments with plains of several duplex soils that support a great diversity of vegetation types. It includes a variety of kwongan heaths and mallee and banksia shrublands. A stable landscape unit that is poorly adapted to frequent disturbances.

10.9%

/southern



Quartzite Range

Metamorphosed sedimentary rocks that began as prehistoric river deltas, later turned to rock by the rifting of Australia and Antarctica and have since resisted weathering to remain standing as the jagged low mountains known as the Barrens. Is primarily mountain thicket, heaths and mallee-heath vegetation. Refugial in nature, the barrens supports high numbers of endemic and threatened taxa.

7.6% / the Barrens

Yilgarn Block East

A complex mix of soil systems underlying a climatic transition zone supporting many different vegetation types, including tall woodlands, semi-arid mallee banksia shrubland and rich kwongan heathlands.

50.6% /northern


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