Herdsman Lake - WA080
Level of importance: National - Directory
Location: 31 degrees 55' S, 115 degrees 48' E, 5.5 km north-west of Perth G.P.O. (within inner Perth Metropolitan Area).
Biogeographic region: Swan
Shire: City of Stirling.
Area: 250 ha.
Elevation: 7 m.
Other listed wetlands in same aggregation: None.
Wetland type: B5, B10, B15, B14
Criteria for inclusion: 2, 3, 4, 6,
Site description: The site is Herdsman Lake, to the maximum high water mark. The lake basin has been reduced in area (cf. most topographical maps) by landfill. Nearby wetlands: Mongers Lake is 1 km east south-east, Swan-Canning Estuary (WA091) is 5.5 km south-east, Joondalup Lake (WA081) is 14.5 km north.
Physical features: Landform: Macroscale irregular-ovoid lake, considerably modified at margins by landfill and excavation, with a deep marginal "moat" to 200 m width now encircling (except in the NW) the unmodified inner parts of the lake. Geological setting: Situated in the Perth Basin, in a depression in the Karrakatta Unit of the Spearwood Dunes, with substantial lake-bed deposits of peat. Climate: Median and mean annual rainfall at Floreat Park are 786 mm and 780 mm respectively, mostly falling in May-August; annual evaporation is c. 2000 mm.
Hydrological features: Hydrological Role: Used artificially as a compensation basin for urban stormwater. Water Supply: Formerly a surface expression of groundwater; now receives most of its water from drains originating up to 4 km distant in surrounding suburbs (Osborne Park, Woodlands, etc.). There is an outflow drain to the ocean (4 km west); rate of discharge is controlled. Inundation: Artificially deepened areas are permanent; interior, unmodified areas are seasonal, usually dry in late summer and early autumn. Water depth: Excavated areas are up to c. 12 m deep; inner areas may be up to c. 1 m deep in spring. Water salinity: Mean salinity in 1990-2 was 0.68 ppt; i.e. fresh, poikilohaline. Water pH: Mean, 1990-2, was 8.6. Water colour: None (EPA/WAWA 1990; Storey et al. 1993).
Ecological features: Ecological role: A major breeding area for waterbirds, especially Black Swan Cygnus atratus, in south-western Australia; also a significant drought refuge area for waterbirds in the Perth Metropolitan Area. Plant structural formations: Mainly closed sedgeland, formerly in latiform arrangement but modified to paniform arrangement; surrounding areas are totally urbanised other than several parkland areas abutting the lake.
Significance: A good example of a large lake/marsh remaining in an inner metropolitan area; a good example of a highly disturbed lake that has been physically modified to improve conservation values.
Notable flora: Threatened Species: None. Composition: The sedgeland is dominated by bulrush Typha orientalis; small areas of Baumea articulata still occur and Bolboschoenus and Cyperus spp. occur on the open areas that dry out in summer. Small areas of paperbark Melaleuca rhaphiophylla occur at the edges and some have been planted; a few exotic willows Salix sp. occur near drains. Ground plants in the wetland interior include Cynodon, Rumex, Pennisetum, and Centella spp. Aquatics present include Chara, Potamogeton and Lemna spp. (Curry 1981).
Notable fauna: Threatened Species: Australasian Bittern Botaurus poiciloptilus (Sr) is sometimes reported (e.g. calls heard) but there are few confirmed recent sightings. Composition: 65 species recorded (regional rank 6), 13 listed under treaties. The 65 include 5 darters and cormorants, 13 herons and allies, 13 ducks and allies, seven rails and 19 shorebirds. Black Bittern Dupetor flavicollis formerly occurred (1902), but there are few confirmed recent sightings. Two Painted Snipe Rostratula benghalensis were collected in 1897, and a single Pectoral Sandpiper Calidris melanotos was recorded several times in the early 1980s, and two Gallinago snipe, possibly Pin-tailed G. stenura, were found in open parts of the interior in summer-autumn 1989. Long-toed Stint C. subminuta sometimes occurs at drying edges and interior open areas, with highest count of 24 in January 1981. Two Little Ringed Plover Charadrius dubius were reported in 1991 (Mueller 1991). A Freckled Duck Stictonetta naevosa was seen in April 1981. Breeding: 18 species found breeding (regional rank 6); most of these breed regularly, notably Great Crested Grebe Podiceps cristatus, Black Swan (up to 50 nests counted, August 1980), Pacific Black Duck Anas superciliosa, Hardhead Aythya australis, Blue-billed Duck Oxyura australis, Purple Swamphen Porphyrio porphyrio, Eurasian Coot Fulica atra, Clamorous Reed-Warbler Acrocephalus stentoreus and Little Grassbird Megalurus gramineus. Little Bittern Ixobrychus minutus was found breeding in spring-summer of 1980 and 1987 and probably breeds regularly in tall dense Typha. Migration Stop-over: 11 migrant shorebirds recorded; about half occur regularly, none in large numbers. Numbers: The highest number of waterbirds counted was 2434 during 1990- 2 surveys; more than 1000 occur in most years. The most abundant species are Eurasian Coot (up to 680, March 1988), Black Swan (617, March 1987) and Australasian Shoveler Anas rhynchotis (500, January 1982, regional rank =8). The site supports more than 1% of the probable national population of Long-toed Stint. It is regionally significant for Glossy Ibis Plegadis falcinellus (up to 20, regional rank 4) (Serventy & Whittell 1976; Curry 1981; RAOU/WADCALM surveys 1981-91; Storey et al. 1993).
Other Fauna: Threatened Species: None. Composition: The Oblong Tortoise Chelodina oblonga, Swan River Goby Pseudogobius olorum, and exotic Mosquitofish Gambusia holbrooki occur. At least 67 invertebrate taxa have been recorded; these include seven Odonata and 12 Chironomidae (Davis et al. 1991; S. Halse pers. comm.).
Social and Cultural values: Education: The Herdsman Study Centre, on the south edge of the lake, provides opportunities for students and public to learn about the lake's ecology. The Centre has an elevated viewing area, displays of live wetland fauna and boardwalks for visitors to enter the sedgeland and paperbarks. It has permanent staff and is operated by the Gould League of W.A. Research: Numerous research projects have been conducted, e.g. on waterbird usage of the lake (P. Curry), the effects of model boat use on waterbirds (R. Van Delft & M. Bamford), and the impact of Argentine ants on waterbird breeding (S. Gordon). Research by RAOU (23 waterbird surveys, 1981-8), RAOU/WADCALM (ten surveys of waterfowl, 1986-91), and universities (e.g. J. Davis et al., invertebrates). Recreation: Popular for bird-watching, picnics, model boat use. Aesthetics: A substantial break in the urban sprawl of Perth, offering easy viewing of a diverse waterbird fauna.
Land tenure: Mostly owned by W.A. Ministry for Planning (MFP), also some drainage reserves. Surrounding area: Mainly freehold.
Current land use: Nature conservation, education, recreation and drainage. Surrounding area: Recreation, urban area (high human population), industrial area (light industries) and land-use is subject to zoning controls. The lake has no buffer of native vegetation.
Disturbance or threat: Past/present: Eutrophication (park, crop and garden fertilisers; resultant algal blooms), water pollution (pesticides used to control Argentine ants; heavy metals from industry), exotic plants (Typha orientalis spreading over few remaining open shallow areas; pampas grass Cortaderia selloana; other weeds) and exotic animals (mosquitofish Gambusia holbrooki, feral and domestic cats). Former use of the lake for agriculture led to invasion by T. orientalis to almost total exclusion of native species. Peat and sand were mined in the 1970s-1980s as part of the lake modification process. A major occurrence of Argentine ant Iridomyrmex humilis in the lake led to spraying of sections of the lake with "heptachlor" over several decades, but this control method has now ceased. The ants may be contained to some extent by the moat when completed.
 
 Potential: No information.
Conservation measures taken: Eventually to become a regional park. The site has been subject to considerable action aimed at improving the quality of the wetland for waterbirds: e.g. creation of encircling moat to protect inner areas from disturbance (including fire) and provide permanent water, planting of trees and shrubs, public education/awareness projects. Part of the vegetation of the site has been identified as regionally significant bushland and recommended for protection (Western Australian Planning Commission, 1998). The site is subject to the Swan Coastal Plain Lakes Environmental Protection Policy (Government of Western Australia, 1992b). National: The site is included on the Register of the National Estate.
Management authority and jurisdiction: Currently managed by MFP and WAWA; the proposed regional park will be managed by WADCALM and WAWA.
References: See Western Australia Reference List
Compiler & date: Roger P. Jaensch in 1992. Minor revision by Romeny J. Lynch and WADCALM staff in 1995 and Sue Elscot in 2000.
Drainage: