Journal of the Royal Society of Western Australia, 83: 293-316, 2000 Peripheral wetland habitats and vegetation of the Leschenault Inlet estuary L Pen1, V Semeniuk2 and C A Semeniuk2 1Water & Rivers Commission, Hyatt Centre, 3 Plain Street, Perth WA 6000 email:
[email protected] 2V & C Semeniuk Research Group, 21 Glenmere Road, Warwick WA 6024 Abstract Along the Leschenault Inlet estuary shore, interactions between ancestral landforms comprising the eastern shores, dune dynamics and the young western barrier dune shore, hydrodynamic processes, estuarine coastal processes, estuarine sedimentation, and a variable Holocene sealevel history, have resulted in a varied peripheral shore and wetland types. The shoreline habitats include supratidal tidal flats (vegetated dominantly by samphire), high tidal platforms (vegetated dominantly by samphire or rushes), tidal embayments (residing between dune corridors), high tidal platforms and dune interfaces, in zones of freshwater seepage (vegetated dominantly by rushes), cliffed sandy shores where coastal erosion is incising into dunes, steep dune shores where dunes are encroaching into the estuary, beachridges, spits, bar-and-lagoon complexes, stranded (relict) sand platforms, the Collie style deltaic complex, and the Preston style deltaic complex. Five broad categories of vegetation fringe the Leschenault Inlet estuary, classified on structure, salinity of habitat, and location relative to shore: 1) saltmarsh; 2) estuarine fringing forest; 3) fringing vegetation; 4) sandy rise vegetation; and 5) freshwater vegetation (forest and disturbance-related assemblages). Saltmarshes, comprising samphire and rush formations, develop in saline tidal areas. Estuarine fringing forest, typically small saltwater sheoak (Casuarina obesa), saltwater paperbark (Melaleuca cuticularis), paperbark (Melaleuca viminea), and swamp paperbark (Melaleuca rhaphiophylla), occurs as elevation increases and where soilwater salinity is not extreme.