Workshop Notes Perth Region Plant Biodiversity Project Jarrah Forest Reference Sites of the Perth Metropolitan Area: The Southern Transect Shaun Molloy February 2008 Lithic complex (reference point MN2) Photograph by Shaun Molloy - 1 - Introduction Bush Forever is a 10 year strategic plan instigated by the Western Australian Government in conjunction with the general community and appropriate Local Government organisations to protect some 51,200 hectares of regionally significant bushland in 287 Bush Forever Sites, representing, where achievable, a target of at least 10 percent of each of the original 26 vegetation complexes of the Swan Coastal Plain portion of the Perth Metropolitan Region. Subsequent to Bush Forever, the Perth Biodiversity Project identified the need to catalogue and describe a series reference sites to facilitate consistency in the assessment of local natural areas and to further enhance the capacity of relevant people to undertake site recording tasks. To this end 40 reference sites were established based on Bush Forever on the Swan Coastal Plain part of the Perth Metropolitan Region (PMR) as part of the Perth Region Plant Biodiversity Project (PRPBP), a collaborative project between the WA Local Government Association’s Perth Biodiversity Project and the Department of Environment and Conservation. The PRPBP recognises a need to provide a fuller appreciation of the diversity of native vegetation found within the PMR. To that end, it was decided to establish reference sites within, or in close proximity to, Darling Plateau part of the PMR. It is proposed that these reference sites are established so as to represent major variations found in the plant communities found within this area thereby complementing reference sites already set up on the Swan Coastal Plain as part of the Perth Biodiversity Project. The purpose of this document is to provide information applicable to the management of Bushland within the PMR part of the Jarrah Forest, and to describe the reasoning for selecting the sites used in the PRPBP Jarrah Forest Reference Sites. Jarrah Forest The Jarrah Forest Interim Biogeographical Regionalisation of Australia (IBRA) region covers an area of approximately 5.4 million hectares stretching from the Shire of Chittering in the north to near Albany in the south (Commonwealth of Australia 2001), although smaller outlying populations of Jarrah (Eucalyptus marginata) occur outside of the Jarrah Forest Region extending into the Wheatbelt and Swan IBRA regions. Jarrah forest itself, generally occurs on the duricrusted plateau of the Yilgarn Craton and is characterised by Jarrah- Marri (Corymbia calophylla) woodlands on laterite gravels, bordered by Wandoo (Eucalyptus wandoo)- Marri woodlands on clayey soils to the east, Darling Scarp shrublands to the west and Karri (Eucalyptus diversicolor) forests to the south. Within this region are areas of eluvial (wind deposited) minerals and alluvial (water deposited) landforms support diverse shrublands. In areas of Mesozoic (248-65 mya) sediments (common in broad valleys throughout the region), Jarrah forests occur in a mosaic with a variety of species- rich shrublands. - 2 - The climate of the Jarrah Forest region is described as warm and Mediterranean. Rainfall varies from 1,200 mm in Serpentine and the lower south west to 500 mm in the east most of which falls between June and September (May and McKenzie 2003). Unlike most of the world’s hardwood forest trees, Jarrah occurs as an almost pure stand within the Jarrah Forest region (although outlying populations are usually far less homogenous in structure). Few other trees grow in association with Jarrah, and those that do have specialized requirements and/or prefer soils other than pure laterite. Marri, Wandoo and Powderbark Wandoo (Eucalyptus accedens) prefer clayey soils, Bullich (Eucalyptus megacarpa) preferring wetter sandy duplex soils on valley floors, Flooded gum (Eucalyptus rudis), Blackbutt (Eucalyptus patens), and Melaleuca rhaphiophylla are generally associated with water courses, Melaleuca preissii and Swamp Banksia (Banksia littoralis) being associated with swamps, and Rock Sheoak (Allocasuarina huegeliana) being mainly associated with granite outcrops (Erickson et al 1973). Most other trees that grow in association with Jarrah usually form a second story or are found in small isolated stands. Foremost amongst these are Allocasuarina fraseriana and proteaceous species such as; Banksia grandis, Persoonia longifolia, Persoonia elliptica, Dryandra sessilis and in some areas Banksia menziesii, Banksia attenuata and Banksia prionotes. Beneath the relatively homogenous canopy of the Jarrah Forest there is often found deceptively diverse shrub and herbaceous understorey layers (Erickson et al 1973). These layers can vary from near monocultures in composition to highly diverse understorey mosaics. This diversity of structural units is, in many cases, as much due to disturbance history as it is to variations in climate and geology. There are 3850 current, native flora taxa listed on Florabase (WA Herbarium 1998-) within the Jarrah Forest IBRA region. The Darling Scarp forms the western edge of the Darling Range. This is the surface expression of an extensive geological structure known as the Darling fault. The scarp rises steeply to more than 200 meters above sea level, where it flattens out to form the Darling Plateau (Copp 2001). Patterns in the vegetation structure and floristic associations have long been attributed to the influences of the environment, which is evident at the environmental extremes presented by the Darling Scarp. The vegetation of the Scarp forms a variety of structural units varying from open woodlands of Jarrah, Marri, Wandoo, Darling Range Ghost Gum (Eucalyptus laeliae) and Rock Sheoak (Allocasuarina huegeliana), through to herbaceous lithic complexes and extensive shrublands, which, in the northern part of the Scarp, (including the section of the Darling Scarp included in the Perth Metropolitan Region) have been described by Markey (1997)as a series of 13 Floristic Community Types within 3 Super Groups. Six hundred and eighty nine taxa have been documented within the Northern Darling Scarp (Markey 1997). - 3 - Southern PMR Jarrah Forest Reference Sites Bungendore Park - PRPBP Jarrah Forest Reference Site 5 (JF5) Bungendore Park is approximately 38 km SE of Perth within the City Armadale. It is managed by the City of Armadale and a committee of Council, known as the Bungendore Park Management Committee. It includes a large section of the Darling Scarp and adjoining Jarrah Forest covering an area of 498 hectares within which the following vegetation complexes can be found; Dwellingup 2 (D2), Murray 1 (My1) and Darling scarp (DS), (see Bungendore Park Map 1 att.). The reference point selected (BG1 see Bungendore Park Map 2 att.) is relatively central within the Park (BP1 reference site description att.). The park has been under a comparitively frequent burn regime of about a three year intervals in recent times (Lewis 2003) and has been extensively affected by Jarrah Dieback (Phytophthora cinnamomi) which has been managed by phosphate application for about a decade now with varying degrees of success (Kim Sarti pers. com.). The area has significant social value as a popular recreational site and from an indigenous heritage perspective. (Stephens 1997). Prior to European settlement area was populated by the Whadjuk, a local group of Noongar Aboriginal people who lived in the area south of the Canning River. Bungendore Park to the edge of the main walk route (linking Perth to Pinjarra) used by the many groups of Noongar people during their seasonal movements (Stephens 1997). The Bungendore Park area has therefore been historically exposed to a comparatively intensive fire regime. Over 352 species have been recorded in the park, of which 33 are introduced. Significant flora such as Thelymitra stellata (DRF), Calothamnus rupestris (P4) have also been recorded (Lewis 1999). A total of 82 bird species have been recorded from Bungendore Park (Johnstone 1996). Western Grey Kangaroos Macropus fuliginosis has been observed on site as have Echidnas Tachyglossus aculeatus, Mardo Antechinus flavipes, Brushtail Possum Trichosurus vulpecula, Brushtailed Phascogale Phascogale tapoatafa and Quenda Isoodon obesulus. Chudich Dasyurus geoffroii has found in the vicinity (Stephens 1997). Numerous reptile, frog and invertebrate species have been observed in the reserve, but have not been listed (Stephens 1997). Bungendore Park forms an ecological linkage to; road reserves, Neerigen Brook and Wungong Brook riparian reserves, remnants in surrounding private property, State Forest, water reserves and the Darling Range Regional Park. The reference site selected (BP1, see Bungendore Park Map 1 att) is situated centrally within the park within an area of the Dwellingup 2 (D2) Vegetation Complex (Havel and Mattiske 2000). In general this site complies very well with the representational landscape provided by Havel and Mattiske (2000) in Appendix 257 (att.) and as such provides a convenient opportunity to introduce participants to the flora and geology of the Darling Plateau Jarrah forests and the Darling Scarp. It provides a good example of the Havel vegetation site type S1 (see appendix att.). It also provides an opportunity to discuss the impacts of a high frequency fire regime. A site description summarising the known values of the site is attached. - 4 - Jarrahdale State Forest - PRPBP Jarrah Forest