endangered by Jill Pryde Shrublands on dry typically contains an average of in small patches of bushland from 52 species within 100 square Armadale south to Busselton. clay flats metres. As the name suggests, About one-third of this area is Seasonally wet clay-based this community is dominated protected within reserves for wetlands are among the most by a dense shrub layer. Typical conservation. threatened plant communities in shrubs include furrowed hakea Threats to the clay pan Western Australia. One particular (Hakea sulcata), variable-leaved community include weed invasion, clay pan community found only hakea (H. varia), swamp tea- rising saline groundwater, changes on the Swan Coastal Plain is tree (Pericalymma ellipticum), to drainage, drying climate and ‘Shrublands on dry clay flats’. It compacted featherflower possibly too-frequent fires. Many was described in a 1994 report (Verticordia densiflora), fringed occurrences of this community about the vegetation that occurs regelia (Regelia ciliata) and are small and fragmented and are on the southern Swan Coastal swishbush (Viminaria juncea). often dissected with drains, or have Plain, and is one of four clay- During spring, as water begins been disturbed for infrastructure based wetland communities to recede, a suite of herbs such as roads. The community listed as threatened in WA. The appears and includes the pointed is also vulnerable to nutrients community is currently ranked as centrolepis (Centrolepis aristata), from run-off, from sources such endangered. Aphelia cyperoides, procumbent as roads, drains and agricultural ‘Shrublands on dry clay flats’ siloxerus (Siloxerus humifusus), lands. Changes to the cycle of is the fastest drying of the clay- sundews Drosera gigantea subsp. wetting and drying of the wetlands based wetlands identified on the gigantea and Drosera menziesii are potentially a significant threat southern Swan Coastal Plain. The subsp. menziesii, and the weed as the community is dependent on thin soils are soaked by winter tiny flatsedge (Cyperus tenellus). these. The significant decline in rainfall and local surface water The heavy soils of this clay winter rainfall on the Swan Coastal pan community were useful for flows, and, as temperatures rise, Plain in recent years affects this agriculture and were mostly dry to a hard clay pan in summer. cycle, and this drying trend is This community typically occurs in cleared and drained soon after predicted to continue. A recovery low-lying areas that hold surface settlement, or the clay was used plan is currently being prepared water, and groundwater levels may for brick and tile production. for the community and will outline come close to or reach the surface Many of the remaining clay actions such as weed control, in wetter months. pans were close to Perth, and drainage management, fire control As clay-based wetlands were later cleared for residential and monitoring. dry they display a vast range development. of colourful flowering herbs. Now, only about 83 hectares of ‘Shrublands on dry clay flats’ the clay pan community remains Photos by Jill Pryde LANDSCOPE 45.