Barrier (Br)

A study of the land in the Catchment of Gippsland Lakes - Vol 2 - land system Barrier - geo

Area: 78 sq. km (0.5%)

Dunes, sandy rises and sand sheets occur in inland positions. Some of these are old coastal dune and harrier systems were stranded following tectonic uplift, while others were built by inland aeolian activity. The scattered remnants of the old harriers and dunes are now much modified by dissection and deflation and, although obvious on aerial photos, are not always prominent in the field. Sometimes the steep, seaward dune faces have been retained, with wind deformation concentrated on the landward side, producing parabolic dunes. In the Seaspray-Dutson area, extended linear forms persist. The largest harrier and dune forms are mapped in this Barrier land system. The associated low dunes, sand sheets and rises are in Perry land system.

The soils are mostly acidic, infertile, and droughty sands, dark at the top and bleached in the subsurface. Iron and/ or humus-enriched, soil horizons, either hardpans or soft layers, occur at depth. The soils are susceptible to wind erosion.

The vegetation is mainly ferny woodland or ferny open woodland I and II, with heathy open woodland I on the deeper sands of upper slopes. Sedgeland occurs in swales with open forest I on the margin.

A study of the land in the Catchment of Gippsland Lakes - Vol 2 - land system Barrier - image

Banksia serrata (saw banksia) and bracken growing on low sand ridges

CLIMATE Rainfall, mean (mm) Temperature, mean (°C) Seasonal growth limitations	Annual 500 - 800; lowest January (30 - 50), highest October (40 - 70) Annual 12 - 14: lowest July (9 - 10). highest February (19 - 20) Temperature <10°C (av.): June - August Rainfall < potential evapotranspiration: November - March
GEOLOGY Age, lithology	Pleistocene aeolian and coastal sand deposits
PHYSIOGRAPHY Landscape Elevation range (m) Relative relief (m) Drainage pattern Drainage density (km/km²)	Large linear and deformed parabolic dunes. sometimes originating from stranded coastal harriers 0 – 120 0 - 20 Nil 0
PRESENT LAND USE	Mostly uncleared: hardwood forestry (minor timber products); bush grazing of cattle (limited); apiculture (limited); small area in Moormurng Forest Park

A study of the land in the Catchment of Gippsland Lakes - Vol 2 - land system Barrier - cs

A study of the land in the Catchment of Gippsland Lakes - Vol 2 - land system Barrier - graph

LAND COMPONENT Percentage of land system Diagnostic features	1 75 Barrier beach-ridges	2 15 Parabolic dunes	3 10 Swales
PHYSIOGRAPHY Slope %, typical and (range) Slope shape	5, (0 - 20) Concave and convex	5, (0 - 15) Concave and convex	<1, (0 - 2) Straight and concave
SOIL
Parent material	Wind-sorted sand		Wind-sorted sand; possibly lacustrine silt and clay
Description	Dark sand over pale or whitish sand over coffee rock or uncemented bright yellowish brown sand; yellow sand at depth		No observations
Classification	Podzols, Siliceous Uc2.32, Uc2.36, Uc4.21, Uc4.22, Uc4.32, Uc4.33		Probably Gleyed Podzolic Soils; Humic Gleys -
Surface texture	Sand		Sand
Surface consistence	Loose or soft		Loose or soft
Depth (m)	>2.0		>2.0
Nutrient status	Very low		Very low
Available soil water capacity	Very low		Very low
Perviousness to water	Very low		Very rapid
Drainage	Somewhat excessive		Very poor to somewhat poor
Exposed stone (%)	0		0
Sampled profile number	71	-	-
NATIVE VEGETATION Structure of vegetation and characteristic species of dominant stratum (+ Predominant species)	Mainly ferny or open woodland I, II: E. globoidea+ (usually clay at depth) or E. viminalis var. racemosa+, Pteridium esculentum and sometimes Banksia serrata Heathy open woodland I: E. nitida+, B. serrata		Mainly sedgeland with Lepyrodia muelleri+, Lepidosperma longitudinale. Schoenus brevifolius Occasionally open heath of Leptospermum juniperinum Margins with open forest I of E. ovata+ and/or E. cephalocarpa+

Disturbance	Affected process and trend	Primary resultant deterioration			Casual activities	Primary off-site process
Disturbance	Affected process and trend	Form	Susceptibility of components	Incidence with components	Casual activities	Primary off-site process
Alteration of vegetation: — reduction in leaf area, rooting depth and/or perenniality	Reduced transpiration, resulting in increased deep percolation and leaching	Nutrient loss	1,2; high 3; low	Not determined	Removal of trees	Increased movement water to groundwater increased base-flow of streams
Increased exposure of surface soil	Increased wind velocity over soil and increased detachment of sand	Wind erosion	12; high	Uncommon locally on topographically exposed sites	Trafficking. overgrazing, rabbit burrowing, cultivating, earthmoving activities.	Encroachment by sand
Increased physical pressure on soil	Increased compaction	Structure decline	1.2; very low 3: low - moderate	Uncommon	Increased trafficking and cultivation. overgrazing, export of organic matter	-
Increased soil disruption	Increased loosening of sand	Wind erosion	1.2; high	Uncommon	Trafficking, overgrazing, rabbit burrowing. cultivating, earthmoving activities.	Encroachment by sand
Comments: Regeneration of vegetative cover is usually slow because of droughty soils with low fertility.

Page top