Tyers (Ts)

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

Area: 5 sq. km (<0.1%)

Tyers land system occurs on the Lake King side of the inner barrier where subsidence of the Pleistocene part of the barrier left only the tops of the old dune system protruding above lake level. Lacustrine and paludal in-filling has produced swampy flats between the old dune crests and these flats and remnant dunes are mapped in Tyers land system. The larger swamps are in Morass land system. The land forms are similar to those of Wollaston land system but their genesis is different. Also, the climate is more humid in Tyers land system.

The sandy soils are acidic, infertile and droughty, with dark topsoils, bleached subsurfaces and iron and/or humus-enriched pans at depth. The dunes are susceptible to wind erosion upon disturbance.

The ferny open woodland I of the dunes and the open woodland I of the flats are dominated mainly by E. botryoides and E. viminalis var. racemosa with Banksia spp. Salinas are bare of vegetation in the deepest parts and successively shallower areas towards the shore carry herbfield, rushland and a fringe of closed shrubland.

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

This large-scale aerial photograph of an area in the north-east of Raymond Island shows the swampy flats (shrubby vegetation, lower left) and the tops of old dunes (trees, upper right), representative of Tyers land system.

CLIMATE Rainfall, mean (mm) Temperature, mean (°C) Seasonal growth limitations	Annual 600 - 900; lowest July or August (40 - 70), highest October (60 - 90) Annual 12 - 14; lowest July (9 - 10), highest February (19 - 20) Temperature <10°C (av.): No months Rainfall < potential evapotranspiration: December – March
GEOLOGY Age, lithology	Pleistocene barrier deposits of sands; Holocene lacustrine and paludal fills of fine sands and probably some peat
PHYSIOGRAPHY Landscape Elevation range (m) Relative relief (m) Drainage pattern Drainage density (km/km²)	Partly buried dune systems with intervening swampy in-filled flats 0 - 20 0 - 20 Nil 0
PRESENT LAND USE	Mostly uncleared: areas in the Gippsland Lakes Coastal Park; some apiculture; holiday housing

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

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

LAND COMPONENT Percentage of land system Diagnostic features	1 25 Dunes — the relict dune crests left above lake level after subsidence of the barrier	2 25 Flats and plains — deposits in submerged interdune areas	3 50 Drainage depressions, intermittently or permanently inundated
PHYSIOGRAPHY Slope %, typical and (range) Slope shape	10 - 15, (3 - 30) Convex	<1, (0 - 2) Straight	<1, (0 - 2) Concave
SOIL
Parent material	Aeolian sand	Lacustrine and paludal sand	Aeolian sand
Description	No observations — probably acidic sand over coffee rock	No observations — probably acidic sand	No observations — probably black acidic sand over grey sand; may be saline in places
Classification	Podzols	-	Humic Gleys
Surface texture	Sand	Sand	Sand
Surface consistence	Loose or soft	Loose or soft	Soft
Depth (m)	>2.0	>2.0	>2.0
Nutrient status	Very low	Very low	Very low
Available soil water capacity	Very low	Very low	Very low
Perviousness to water	Very rapid	Very rapid	Very rapid
Drainage	Somewhat excessive	Somewhat excessive	Very poor to somewhat poor
Exposed stone (%)	0	0	0
Sampled profile number	-	-	-
NATIVE VEGETATION Structure of vegetation and characteristic species of dominant stratum (+ Predominant species)	Limited data — probably ferny open woodland I: E. botryoides+ and/or E. viminalis var. racemosa+ with Banksia serrata or B. integrifolia (near lake shores) and Pteridium esculentum	Limited data — probably open woodland I: E. botryoides+ with B. integrifolia	Limited data — probably zonation of vegetation with, from margins inwards: Closed scrub of Melaleuca ericifolia Rushland of Juncus maritimus Herbfield of Salicornia spp. Centres often with free water

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; high	Not determined	Removal of trees	Increased movement of 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	1; high 2; low	Uncommon: but locally severe	Clearing, burning, road and dam building and other earth-moving activities, trafficking by stock and vehicles.	Encroachment by sand
Increased physical pressure on soil	Increased compaction	Structure decline	1; very low 2,3; low	Uncommon	Increased trafficking, export of organic matter	-
Increased soil disruption	Increased loosening of sand	Wind erosion	1; high 2; low	Uncommon: but locally severe	As for wind erosion above	Encroachment by sand
Comments: Regeneration of vegetative cover on the dunes is usually slow because of low-fertility soils and exposure to wind

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