Brixton Street Field Herbarium
A flora identification tool for managers of seasonal clay-based wetlands

Flora of the Brixton Street Wetlands

Brixton Street Wetlands, a 19ha A Class Nature Reserve, lies 20km southeast of Perth at the foot of the Darling Scarp. Managed by the Department of Biodiversity, Conservation and Attractions, the area is part of the Greater Brixton Street Wetlands, one of the largest (175ha) and most significant areas of remnant vegetation on the Pinjarra Plain.

While the majority of seasonal wetlands in south-west Australia are connected to the regional ground water, some such as the Brixton Street Wetlands rely almost solely on rainfall to fill. The winter-wet flats of Guildford formation clays are waterlogged through the winter months and deep pools form in clay depressions. When the pools are full they support a range of native aquatic plants including stalked water ribbons (Aponogeton hexatepalus) and aquatic pennywort (Hydrocotyle lemnoides). As the water levels start to drop a series of annual and perennial herbs grow and flower. In late winter flannel flowers (Tribonanthes species), blue squill (Chamaescilla species) and early nancy (Wurmbea dioica) are flowering and by late spring swamp wallaby grass (Amphibromus nervosus) is in abundance. By early summer the pools are dry and the claypans are covered in sundews (Drosera species) and trigger plants (Stylidium species). The flats surrounding the claypans also support a range of native herbs, sedges and rushes. Shrubs, including swishbush (Viminaria juncea) and feather flowers (Verticordia species), are also common. On the sandy rises, marri (Corymbia calophylla) woodlands occur and in spring, red and green kangaroo paw (Anigozanthos manglesii), flower throughout their understorey. The reserve supports an incredibly diverse flora of around 350 natives and with this kind of habitat almost entirely cleared on the Swan Coastal Plain the area is of outstanding conservation significance.

Compilation of the Brixton Street Field Herbarium

Collections made on monthly and opportunistic site visits to the wetlands throughout the year over a five year period formed the basis of the field herbarium. Specimens were photographed in the field, site information documented and fresh material scanned using a flatbed scanner within few hours of collection. Pressed and dried specimens were submitted for incorporation into the Western Australian Herbarium. For each species an image collage, collecting notes and a scan of the fresh specimen have been incorporated into a fact sheet (Fact Sheet Fusion, Lucid software application) The fact sheet also includes a vegetation profile where the horizontal bar indicates the species’ habitat.

The Brixton Street Field Herbarium project is part of the continued documentation of the flora of these critically endangered wetlands and associated woodlands. Knowledge and understanding of their exceptionally diverse flora underpins effective protection, management and restoration of seasonal wetlands. The compilation of a field herbarium including photographs and scanned specimens vouchered at the Western Australian Herbarium provides a flora identification tool for all managers of clay-based wetlands as well as the Friends of Brixton Street Wetlands. Hopefully the field herbarium will assist in restoration and management projects that require a detailed knowledge of a diverse and sometimes cryptic flora.

Not all 310 native species from the original 1995 list (Keighery 1995) were collected but this current project is ongoing and it is intended that new collections and fact sheets will be added over time. Two hundred and fifty vouchers have been lodged at the WA herbarium with 40 new records of native flora for the nature reserve. These include a new record of a declared rare species, and a new record for the Swan Coastal Plain, Comesperma griffinii. The latter is known only from eight collections and the closest collection to Brixton Street is from Dalwallinu 200km to the north east of Perth.

Eighteen new weed species have been added to the original list including serious weeds such as tambookie grass (Hyparrhenia hirta) and Natal redtop (Melinis repens) as well as a new weed record for Western Australia, Acacia debilis. The current subset of the Brixton Street Field Herbarium PDF covers native taxa collected over the time frame of the field herbarium project.

The herbarium has been produced as two PDFs:

The Brixton Street Field Herbarium has been a collaborative project between Department of Biodiversity, Conservation and Attractions’s Swan Region (Urban Nature Program), the Western Australian Herbarium and the Friends of Brixton Street Wetlands. Western Australian Herbarium staff particularly Rob Davies, Mike Hislop, Karina Knight, Ben Richardson, Kevin Thiele and Juliet Wege, assisted with plant identification and provided project support. Matt Taylor (Lucid software development team) provided technical support for the Fact Sheet Fusion program. The Friends of Brixton Street Wetlands and many community volunteers provided outstanding field assistance. The Brixton Street Wetlands vegetation profile illustration was produced by Margaret Pieroni.

References

• Gibson, N., Keighery, G.J., Lyons, M.N. and Keighery, B.J. (2005) Threatened plant communities of Western Australia. 2 The seasonal clay-based wetland communities of the South West. Pacific Conservation Biology, 11(4), pp.287-301.
• Keighery, B. (1995) Knowing and managing the Brixton Street Wetlands, for The Friends of Brixton Street Wetlands and the Perth Branch of the Wildflower Society of W.A. in cooperation with the Department of Conservation and Land Management --[Perth]: Dept. of Conservation & Land Management.
• Marshall, J. (2000) The Greater Brixton Street Wetlands management guidelines, natural history and research, for the Friends of Brixton Street Wetlands Inc. Kenwick, W.A.: Friends of Brixton Street Wetlands.
• Western Australian Herbarium (1998–). Florabase—the Western Australian Flora. Department of Biodiversity, Conservation and Attractions. https://florabase.dbca.wa.gov.au