Landscapes of Warren


Landscapes of Warren

The Warren catchments area encompasses the catchments of the Donnelly, Warren, Gardner, Shannon, Weld and Deep River Systems as well as the Lake Muir Byenup system. The Warren River is the major river, incorporating the Tone, Perup and Wilagarup Rivers. The catchments area contains some highly prized natural assets, in particularly its highly valued waterways and iconic biodiversity. 

Land

The geology of the catchments area is comprised of two principal elements: the Yilgarn Craton occurring east of the Darling Fault, north of Pemberton and the Albany-Frazer Orogoen occurring east of the Darling Fault south of Pemberton. Coastal sediments occur within 10km of the coast (WAPC, 1997).

The Warren catchments area can be divided into three physiographic regions; the Scott Coastal Plain, the Darling Plateau and the Blackwood Plateau.

Learn more about the Scott Coastal Plain, Darling Plateau and Blackwood Plateau.

The Scott Coastal Plain

In the coastal portion of the catchments area, the Scott Coastal Plain is a low-lying, swampy plain featuring windswept parabolic dunes with limestone and granite headlands. Between the headlands are stretches of exposed beaches which are punctuated by rivers and estuaries.

Darling Plateau

The Darling Plateau dominates the landscape of the Warren catchments area, and greatly influences localised climatic conditions, particularly rainfall, and vegetation communities. It is an undulating, dissected peneplain with gravelly, pale orange soils cloaked by extensive areas of tall forest. Deep, steeply sided valleys occur throughout this area, occasionally punctuated by impressive dome-shaped granite outcrops.

Soils are predominantly gravels within occasional block laterite outcrops and some elevated area s of sands and sandy loams. In the deeper valleys the soils are heavier alluvials. The Manjimup-Pemberton areas have considerable areas of heavy red loams, or karri loams, which are of significant horticultural values.

Blackwood Plateau

The Blackwood Plateau occurs within the Warren catchments area in a thin wedge between the Darling Plateau and Scott Coastal Plain on the western side of the Darling Fault, west of Pemberton. It is a gently undulating plateau with low hilly relief and has broad depressions with swamps, but it is at a lower elevation than the Darling Plateau.

Natural Waterways

The Warren catchments area encompasses the catchments of the Donnelly, Warren, Gardner, Shannon, Weld and Deep River systems as well as the Lake Muir Byenup system. The Warren River is the major river, incorporating the Tone, Perup and Wilagarup Rivers

The Warren sub-region has approximately 41 major streams and rivers which feed into three major rivers: the Donnelly River, Warren River and Shannon River. These waterways are also used intensively in agriculture/horticulture and recreation activities.

Most are recognised as being in pristine condition with unique biodiversity, having innate value as wilderness and hosting important natural processes, providing important freshwater habitat for a variety of aquatic flora and aquatic fauna, often unique to the area. River estuaries are important for bird and fish species.

The Warren River suffers serious salinity and is a Recovery Catchment under the WA Salinity Action Plan.

Wetlands

The Warren catchments area contains a diverse range of lake and wetland systems that include salt lakes, coastal lakes, pristine freshwater forested lakes and wetland systems. All have important values that include biological processes, degree of interconnection, freshwater quality, water/nutrient filter systems, migratory bird habitat, general habitat and refuge for aquatic and terrestrial flora and fauna.

The Lake Muir Byenup System is a listed Ramsar site and is located close to the eastern boundary of the catchments area, south of Muirs Highway. Learn more.

Gingilup Jasper wetland system is located on the southern coast of the catchments area (crossing over into the Blackwood catchment). Learn more.

Biodiversity

Areas Managed for Conservation 

Approximately 70% of the catchments area is within Department of Parks and Wildlife estate, with almost 30% of this being State Forest and Timber Reserve. Numerous National Parks exist including:

  • D’Entrecasteaux National Park
  • Boorara-Gardner National Park
  • Boyndaminup National Park
  • Dalgarup National Park
  • Gloucester National Park
  • Greater Beedelup National Park
  • Greater Dordagup National Park
  • Greater Hawke National Park
  • Greater Kingston National Park
  • Hilliger National Park
  • Jane National Park
  • Lake Muir National Park
  • Milyeannup National Park
  • Mount Frankland National Park
  • Shannon National Park
  • Sir James Mitchell National Park
  • Walpole-Nornalup National Park
  • Warren National Park
  • Walpole-Nornalup Inlets Marine Park

And many smaller reserves:

  • Alco Nature Reserve
  • Blackbutt Conservation Park
  • Bokarup Nature Reserve
  • Brockman National Park
  • Cobertup Nature Reserve
  • Cootayerup Nature Reserve
  • Cowerup Nature Reserve
  • Donnelly River Nature Reserve
  • Jingalup Nature Reserve
  • Kodjinup Nature Reserve
  • Kulunilup Nature Reserve
  • Lake Muir Nature Reserve
  • Mettabinup Nature Reserve
  • Mininup Nature Reserve
  • Noobijup Nature Reserve
  • Pindicup Nature Reserve
  • Quindinup Nature Reserve
  • Smith Brook Nature Reserve
  • South Jingalup Nature Reserve
  • Tone-Perup Nature Reserve
  • Unicup Nature Reserve
  • Whistler Nature Reserve
  • Wilgarrup Nature Reserve.

Vegetation

Approximately 80% of the Warren catchments area is covered in native vegetation with the majority of this occurring within State Forest and conservation reserves as mentioned above. Much of the vegetation is continuous across the landscape, with clearing occurring around the townsites and in the north west corner of the catchments area, above Lake Muir. South, south west and east of Manjimup is the Warren bio-region and north and east of Manjimup is the southern Jarrah Forest bioregion.

Warren Bio-region

The Warren bio-region within the Warren catchments area is a dissected, undulating country of south-west intrusions of the Yilgarn Craton and western parts of the Albany Orogen with loamy soils supporting Karri forest, laterites supporting Jarrah-Marri forest, leached sandy soils in depressions and plains supporting low Jarrah woodlands and paperbark Agonis flexuosa and Banksia woodlands and heaths.

Southern Jarrah Forest Bio-region

The Jarrah Forest bio-region occurs on the Darling Plateau, with the southern Jarrah Forest occurring south of Collie, where the Darling Plateau broadens and is less well drained.  The forest and woodlands are generally similar to those occurring in the northern jarrah forest, but the understorey reflects the wetter conditions. Rainfall is from 1200 mm in the south-west to 500 mm in the east. Vegetation comprises Jarrah-Marri forest in the west grading to Marri and Wandoo woodlands in the east. There are extensive areas of swamp vegetation in the south-east dominated by Paperbarks and Swamp Yate. The understorey component of the forest and woodlands reflects the wetter nature of this area. The majority of the diversity in the communities occurs on the lower slopes or near granite soils where there are rapid changes in site conditions.

Ecological Linkages

Although much of the catchments area is covered in continuous vegetation, important regional ecological linkages have been identified particularly through the fragmented vegetation within the catchment. Remnant vegetation and re-established vegetation, natural waterways and wetlands provide important functions, acting as stepping stones and linkages between the small and large conservation reserves. Regional ecological linkages have been identified across the entire South West NRM region including the Warren catchments area and can be learned about here. Local scale linkages will also play important roles through these fragmented areas especially within and surrounding the townsites and in the north west corner of the region.

Flora

The Warren bioregion has over 1850 vascular plant species, over 70 of these being endemic to the area. The most iconic of the area would be one of the world’s tallest trees the Karri (Eucalyptus diversicolor). Although over 80% of the area is within DPaW estate, approximately 30% of it is designated State Forest. Since 2001, the Old Growth Forest policy has been in place, protecting all old-growth forests in national parks, nature reserves, conservation parks and forest conservation areas.

Data from DPaW’s threatened species database in 2012 identifies 19 threatened species and over 80 priority species. Threatened species include:

  • Andersonia annelsii (CR)
  • Asplenium obtusatum subsp. northlandicum (VU)
  • Brachyscias verecundus (CR)
  • Caladenia christineae (EN)
  • Caladenia dorrienii (EN)
  • Caladenia harringtoniae (VU)
  • Caladenia winfieldii (EN)
  • Diuris drummondii (VU)
  • Diuris micrantha (VU)
  • Drakaea micrantha (EN)
  • Gastrolobium lehmannii (VU)
  • Grevillea acropogon (CR)
  • Kennedia glabrata (VU)
  • Microtis globula (VU)
  • Myriophyllum trifidum (VU)
  • Reedia spathacea (EN) Learn more
  • Rhacocarpus rehmannianus var. webbianus (CR)
  • Verticordia densiflora var. pedunculata (EN)

Threatened Ecological Communities

No threatened ecological communities occur within the catchments area. However, priority ecological communities have been identified. They are:

  • Reedia swamps – Warren Region (Priority 1)
  • Epiphytic Cryptogams of the karri forest (Priorioty 3)
  • Claypans with mid dense shrublands of Melaleuca lateritia over herbs (Priority 1)
  • Southern granite pool community (Muirillup Rock, Northcliffe) (Prioiryt 2)
  • Yate dominated alluvial claypans of the Jingalup Soil System (Priority 1)

where Priority 1 and 2 are poorly known ecological communities (known from <5 occurrences or a total of 100 ha; or < 10 occurrences and a total of 200 ha) or Priority 3 (communities that are known from several to many occurrences, a significant number or area of which are not under threat). See the DPaW TEC definitions here.

Fauna

The Warren catchments area has a diverse range of vegetation types and thus habitats, from forests, to wooded areas, wetlands and coastal zones. It equally supports a diverse range of fauna species. New species are continually being discovered and defined within the region.

Threatened fauna species within the area include:

  • Cape Leeuwin Freshwater snail Learn more
  • Woylie (Brush-tailed Bettong) (CR)
  • Forest Red-tailed Black-Cockatoo (VU)
  • Baudin’s Cockatoo (long-billed black-cockatoo) (EN)
  • Carnaby’s Cockatoo (short-billed black-cockatoo) (EN)
  • Chuditch, Western Quoll (VU)
  • Walpole Burrowing Crayfish (VU) Learn more
  • Numbat (VU)
  • Balston’s Pygmy Perch (VU) Learn more
  • Brush-tailed Phascogale, Wambenger (SW subsp) (VU)
  • Western Ringtail Possum (EN)
  • Quokka (VU)
  • Muir’s Corella (Cacatus pastinator subsp. pastinator) – Other Specially Protected Fauna
  • Pouched lamprey (P1) Learn more
  • Black stripe minnow (P3) Learn more
  • Rakali, Water-rat (P4)
  • Western Brush Wallaby (P4)
  • Quenda, Southern Brown Bandicoot (P5)
  • Tammar Wallaby (WA subsp) (P5)

More can be found about the species and their rankings as well as recovery plans on DPaWs website here.

Marine

The marine environment is isolated and wild. The Southern Ocean is pristine and isolated with iconic wind systems such as the ‘roaring 40s’, the Continental shelf, migrating whales, fisheries and migratory birds. It has a major effect on the catchments area’s weather system – its wind, water cycle, climate and sea levels.

Commercial activities include fishing and seafaring transport routes. Recreation activities include boating and fishing.

Coast

The great majority of Warren’s coast falls within D’Entrecasteaux National Park. Within this area are a variety of coastal lakes, inlets, river estuaries, cliffs and dune systems. All contribute to the area’s unique natural beauty and wilderness values. Only two areas have permanent development: Walpole and Windy Harbour.

The coast is popular for local recreation, holidays and fishing. Commercial operations include fishing (including for abalone) and limestone mining at Point D’Entrecasteaux.

Aboriginal Cultural Heritage

At the time of of European settlement the Warren catchments area was inhabited by Nyoongar people. They moved from the West Coast Plain to the inland heavily forested areas along the river valleys according to seasonal changes and food sources. Even following the disruption of European settlement, a strong Nyoongar identity exists in the region with individuals and families retaining strong ties to particular sites and areas of land.

There are many Aboriginal sites in the region. They include mythological sites, ceremonial sites, burial sites and sites in which past Aboriginal habitation is evident. Learn more.

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