Extract /tom the "Joumal of the Soil Conservation Service of N.S. W.", Volume 27, Number I, January,l971

DETERIORATION OF VEGETATION AND EROSION IN THE GUTHEGA CATCHMENT AREA , N.S.W.

BY

W. G. BRYANT, B.Sc.Agr., Litt.B. Research Officer,

0 36851 DETERIORATION OF VEGETATION AND EROSION IN THE GUTHEGA CATCHMENT AREA, SNOWY MOUNTAINS, N.S.W. BY W. G. BRYANT, B.Sc.Agr., Litt.B., Research Officer, Cooma

Deterioration sequences in a number of Australian high mountain plant communities are described. The relation of these to soil exposure and/ or water table variations is demonstrated. The extent and causes of erosion damage are discussed and the relatively recent origin of the damage commented upon. HE Snowy Mountains Hydro-Electric Snowy Mountains, and is the only exten­ T Scheme, well known throughout Aus­ sively winter snow covered area on the con­ tralia, involves the multiple use of water tinent. through storage structures, race lines, and tunnels to produce peak-load electricity for The whole of the area under consideration nearly half of 's population and is situated above the winter snow line and irrigation water for the vast, and still grow­ comprises those plant communities generally ing, complex of Murray-Murrumbidgee grouped as "alpine" and "sub-alpine" by irrigation and stock watering schemes in Costin (1954 ). The alpine and sub-alpine three States. tracts form virtually the inverted apex of the Snowy Mountains in the far southeast of Dependent as this scheme is upon the being, in their southern­ long-continued supply of water of high most extent, no more than a few miles from quality from the high, snow-fed catchments the Victorian border. Within this area rises of the Snowy Mountains, the individual the . catchment becomes important, particularly if, in any catchment area, deterioration or accelerated erosion is noted. Inefficiency of GUTHEGA CATCHMENT AREA any major or minor catchment area is likely to jeopardize engineering structures, alter Since the major contiguous area of alpine stream-flow patterns and sediment load, and vegetation lies within the catchment of the operational efficiency and the eventual Guthega Pondage, currently the highest life of the system as a whole. water storage in Australia, and since this catchment best illustrates the changes which Against the relative importance of the have taken place in the past 100 years, de­ catchment areas for water yield compared tailed consideration of vegetal changes will with previous returns from snow leases be limited to this area. The area is the very (Taylor, 1956), consideration of the vegeta­ roof-top of Australia, being bounded on the tion of any denuded or eroded area assumes northwest by the main divide, running from national importance. Mount Kosciusko (7,314 feet) through Mount Northcote (7,000 feet), Carruthers The high alpine, or high mountain vegeta­ Peak (7,042 feet), Mount Twynam (7,208 tion of the Australian mainland occupies an feet) and on through Mounts Lee and An­ area of some 2,000 square miles, of which derson; on the northeast by Guthega Pond­ 1,000 square miles lies in southeastern New age and in the southeast by the Ramshead South Wales. It is predominantly within the and Crackenback Ranges (figure 1).

Janufl17, 1971 62 DETERIORATION OF VEGETATION AND EROSION IN THE GUTHEGA CATCHMENT AREA, SNOWY MOUNTAINS, N.S.W. BY W. G. BRYANT, B.Sc.Agr., Litt.B., Research Officer, Cooma

Deterioration sequences in a number of Australian high mountain plant communities are described. The relation of these to soil exposure and/or water table variations is demonstrated. The extent and causes of erosion damage are discussed and the relatively recent origin of the damage commented upon. HE Snowy Mountains Hydro-Electric Snowy Mountains, and is the only exten­ T Scheme, well known throughout Aus­ sively winter snow covered area on the con­ tralia, involves the multiple use of water tinent. through storage structures, race lines, and tunnels to produce peak-load electricity for The whole of the area under consideration nearly half of Australia's population and is situated above the winter snow line and irrigation water for the vast, and still grow­ comprises those plant communities generally ing, complex of Murray-Murrumbidgee grouped as "alpine" and "sub-alpine" by irrigation and stock watering schemes in Costin ( 1954). The alpine and sub-alpine three States. tracts form virtually the inverted apex of the Snowy Mountains in the far southeast of Dependent as this scheme is upon the New South Wales being, in their southern­ long-continued supply of water of high most extent, no more than a few miles from quality from the high, snow-fed catchments the Victorian border. Within this area rises of the Snowy Mountains, the individual the Snowy River. catchment becomes important, particularly if, in any catchment area, deterioration or accelerated erosion is noted. Inefficiency of GUTHEGA CATCHMENT AREA any major or minor catchment area is likely to jeopardize engineering structures, alter Since the major contiguous area of alpine stream-flow patterns and sediment load, and vegetation lies within the catchment of the operational efficiency and the eventual Guthega Pondage, currently the highest life of the system as a whole. water storage in Australia, and since this catchment best illustrates the changes which Against the relative importance of the have taken place in the past 100 years, de­ catchment areas for water yield compared tailed consideration of vegetal changes will with previous returns from snow leases be limited to this area. The area is the very (Taylor, 1956), consideration of the vegeta­ roof-top of Australia, being bounded on the tion of any denuded or eroded area assumes northwest by the main divide, running from national importance. Mount Kosciusko (7,314 feet) through Mount Northcote (7,000 feet), Carruthers The high alpine, or high mountain vegeta­ Peak (7,042 feet), Mount Twynam (7,208 tion of the Australian mainland occupies an feet) and on through Mounts Lee and An­ area of some 2,000 square miles, of which derson; on the northeast by Guthega Pond­ 1,000 square miles lies in southeastern New age and in the southeast by the Ramshead South Wales. It is predominantly within the and Crackenback Ranges (figure 1). lanUfl1'1, 1971 62 VIC. SC/>.LE (Mil.s) 0 5 10 15 LE.GE.ND I Tantangara _____ I Guthega Dam ______--.5 N _____ 2. Guthega Dam CatchmMt Ar~a---~ Ponds Dam ___ 3 Roads _____ ------­l ______4 Railways ______-+-+-+

Figure 1-Guthega dam catchment area, showing its relationship to the Snowy Mountains area

63 Soil Conservation Journal The catchment comprises some 23,000 and at lower elevations it is modified by the acres (approximately 36 square miles) of degree of tree cover. Snow season at Spen­ which 60 per cent is above the tree-line cer's Creek has varied from 3.3 to 7.4 and 40 per cent is occupied by the sub­ months in the period 1954-1964 but is up alpine woodland of Eucalyptus niphophila to 1.5 months longer on the main range. in its various forms. The distribution of precipitation shows Definitions a double peak in midwinter and spring and a distinct summer-autumn minimum. Rain­ The high alpine zone may be described as fall in excess of 2 inches per month may be the area having continuous snow cover for expected each month in 75 per cent of years. at least one month per annum, coinciding Intensities are not high. The highest with the upper limit of the sclerophyll forest. recorded one-hour rainfall is 2.44 inches at It comprises, therefore, Spencer's Creek. Figure 2 illustrates the SuB-ALPINE TRACT-characterized by a con­ precipitation characteristics at Spencer's tinuous snow cover of one to four Creek and Guthega . months per annum and approximates to the range of the pure snowgum Temperatures are mild in summer but (Euc. niphophila) stands. The upper during six months of the winter the mean limit, at varying elevations between of extreme values is less than 22°F. Frosts 6,000 feet and 6,500 feet, is the tree­ occur throughout the year but the period of line determined by the January mean least incidence is during January and temperature isoline of 50°F (Costin February. 1965), whilst the lower limit coincides with the upper limit of other tree Wind velocities are high, 40 mph being species at about 5,000 feet. frequently attained whilst 80~90 mph gusts are not infrequent. ALPINE TRACT-is characterized by a con­ tinuous snow cover for at least four months, and a January mean tempera­ Physiography and Geology ture of less than 50°F. The vegeta­ Relief is suppressed in comparison with tion is characteristically herbaceous, alpine areas elsewhere. Local relief seldom comprising grasslands, het"bfields, exceeds 500-700 feet. Valleys are generally heaths, bogs and associated communi­ U-shaped showing evidence of previous ties. A number of the communities and glaciation, interfluves are generally rounded of the species present are unique on though sharpened somewhat on their south mainland Australia and provide and southeast faces by semi-permanent phytogeographical links with the sub­ snowdrifts. Stream patterns are oriented to Antarctic islands and South America snowdrift sources and often show partial (Costin 1961). structural control.

PHYSICAL ENVIRONMENT Geologically it is a relatively undissected Climate massif, marginally faulted, and underlain by gneissic granites with a narrow band con­ Precipitation varies from 68 inches per sisting of phyllites, schists and quartzites, annum at to 120 running NNW from the Etheridge Range to inches per annum at Mount Twynam and Carruthers Peak (figure 3). It has been decreases to 100 inches in the subject to one or more pleistocene glaci­ and areas, of which up ations of disputed extent and intensity (Gal­ to 25 per cent may fall as snow. Snow cover loway 1963, Brown and Valiance 1963) shows a definite altitudinal relationship while there is also extensive evidence of modified by aspect in the alpine drift areas former intense periglacial activitv.

January, 1971 64 \4 / \ / \ !. IZ I/ / \ / !~"'"' 10 ~\ ' ~" /' \ / v/ / 1\\ -". !------­ ----­ - ["--, 1/ ~ li "'-. r------­V !"-"--.. G L /I\ I li' ...... ---­ '"---- V/ !-----­ / ', ' ' / ' ' ~ I // ' ' ' ' \ ',,,\I / ---- ... _ \ 4 L -­ ' ,. -­ ' ' ...... / --/­ ' ' / ' ' ' / ' // ' I ' ' ' . ' ', ', / ' r----­ -=----f~ -~ f-~-~--- . SPE.NCE.R '5 CRE.E.K

0 l I I J Dec Jan Feb Mar Apr May Jun Ju\ Aug Sep Oct Nov D~c Jan

Upper Quartile Median Lower Quarti/f'.

Dec. Jan Feb Mar Apr May Jun Ju\ Aug Sep Oc t Nov Dec Jan MONTH 'M Figure 2-Precipitation characteristics at Spencer's Creek and Guthega Power Station 65 Soil Conservation Journal Soils opment in this area. The main features are Within the catchment are seven major their considerable depth, acidity regardless soil associations. These have been described of parent material, high organic matter and by Costin (1954) and the most extensive of their relation to drainage and water 'table them fully described by Costin, Hallsworth conditions. The base status of these soils and Woof ( 1952). These soils fall within is related to the occurrence of organic mat­ four main groups. ter. Erosion therefore has a serious deleteri­ ous effect upon fertility as the subsoil ( 1) Soils showing no profile differentiation horizons are acid, highly infertile, low in -largely mineral in nature-Lithosols. soil colloids and organic matter and are (2) Soils in which the profile shows no highly erodible. eluviation of sesquioxides, acid to strongly acid in the surface-Alpine VEGETATION PATIERNS Humus Soils. The vegetation patterns of the area are (3) Soils in which the water table is present intimately dependent upon the relation of in the solum for at least part of the environmental factors as influenced by the year- biotic or anthropogenic factors. They are Silty Bog Soils controlled by four factors: Snow Patch Meadow Soils (a) Climate-the high precipitation, the snow cover and low temperatures. (4) Soils in which the profile is dominated (b) Soils-their acidity, infertility, and the by organic matter, the . botanical fea­ position and permanence of the water­ tures of which are partially visible- table. Humified Peats (c) Past geomorphic process. Bog Peats (d) Settlement history. Fen Peats These soils are characteristic of most Table I relates the major forms to cur­ alpine areas but attain their maximum devel­ rent overseas synonyms.

TABLE I VEGETATION FORMS-GUTHEGA CATCHMENT AREA*

Form Sub-form Synonyms

ALPINE HERBFIELD Tall alpine herbfield . . Alpine meadow, herbfield, herb-moor. Short alpine herbfield . . Mountain meadow. FEN Low-moor, nieder-moor, ftachmoor, marsh, swamp. BoG Valley bog . . Mixed-mire, acid fen, transition fen. Raised bog . . Raised moss, loch moor. FJAELDMARK Fellfield, wind-desert, feldmark, felsen-fturen, fjaeld-marker. WooDLAND . . Sub-alpine woodland . . Alpine woodland. HEATH Heather.

GRASSLAND Wet tussock grassland Meadow grassland. ------'--"S'-o_d._t.::.us_s_oc_k_g"'-I'-.a'-ss,_la.:c:n.:c:d__:_c...:..:.....::.M..::.o::...:untain, alpine, sub-alpine, grassland. *After Beadle and Costin (1952)

January, 1911 66 Figure 3---JGeology of Guthega catchment area-after Snowy Mountains Hydro-Electric Authority geological survey maps The major communities have been fully dominated in its undisturbed state by described by Costin (1954, 1957, 1961). Carex gaudichaudiana. They comprise: (4) Bogs hydrophilous communities ( 1) Tall Alpine Herbfields-a multi­ dominated by hummock-forming storied, closed alpine community dom­ mosses. inated by tall perennial herbs. There (a) Raised Bogs of valley sides domi­ are two communities. nated by Sphagnum cristatum­ (a) Brachycome nivalis-Danthonia Epacris paludosa, Blindia robusta. alpicola alliance of steep rock­ (b) Valley Bogs dominated by faces, crevices, and ledges. Sphagnum cristatum. (b) Celmisia longifolia:--Poa caespi­ (5) Fjaeldmarks-open sub-glacial com­ tosa alliance of freely drained soils munities of dwarf plants, of which throughout the area with species there are two naturally occurring such as Helipterum incanum and forms. Epacris sp. assuming greater im­ (a) Coprosma pumila-Colobanthus portance in exposed situations. benthamianus of snowpatches. (2) Short Alpine Herbfields-closed alpine (b) Epacris petrophila - Veronica community dominated by short, carpet­ densifolia of windswept summits forming herbs and forbs-of restricted and cols. local occurrence. Plantago muelleri-Montia australasica (6) Heaths alliance (a) Epacris serpyllifolia - Kunzea This community may be enriched by muelleri of poorly aerated situa­ Euphrasia, Ranunculus, Craspedia, and tions. Aciphylla. (b) Oxylobium ellipticum - Podocar­ (3) Fen-hygrophilous community charac­ pus alpinus of shallow rocky situa­ terized by free surface water and tions. 67 Soil Conservation Journal (7) Sub-Alpine Woodlands - open or from examination of changes currently ap­ closed woodland of Eucalyptus nipho­ parent within the area, species lists can be phila, at times reduced to the dimen­ compiled for each major community cover­ sions of scrub. Ground stratum varies ing the "decreasers" and "increasers". from sod-tussock grassland or herbfield Probable deterioration sequences can be to low scrub (in rocky situations). constructed, and the potential for recoloniza­ It is doubtful whether any part of any tion can be examined. Of the palatable community has escaped the modifying hand species observed to have been most elim­ of European man, and a number of altered inated by grazing, special mention can be community sequences can be recognized. made of a few notable species. Danthonia One of the most common is the "erosion frigida J. Vickery (D. robusta of McLuckie fjaeldmark" on eroded sites formerly sup­ and Petrie, 1927) was recorded as common porting tall alpine herbfield Poa caespitosa-­ by Helms (1893), Maiden (1899) and Mc­ Celmisia longifolia communities. Luckie and Petrie (1927). Costin (1954) The distribution of the main communities recorded it as formerly common and pos­ is shown in figure 4. sibly eo-dominant with Poa caespitosa (un­ der review) but as rare and only found in VEGETATION DETERIORATION inaccessible places by 1948. Reappearance AND EROSION from these "refuge" sites has been noted Deterioration involves the reduction in increasingly and the author made collections quality or value of the land and it is gen­ from three widely separated localities in erally indicated by the loss of valuable 1964-65 where it was recorded as "from species from the sward. In the extreme case, occasional to a frequent occurrence" in well deterioration is represented by loss of drained, but moist situations of dense snow­ ground cover and by accelerated erosion. grass (Poa caespitosa) sward. Aciphylla glacialis, an extremely palatable semi-succu­ DETERIORATION OF VEGETATION lent perennial herb which had decreased The original state and condition of the to the "rare" category by 1948 is now of vegetation of the area has been described by occasional occurrence over wide tracts of early writers. Helms ( 1896) effectively the alpine herbfields and forms up to 50 per summarises the situation in that year in his cent of the non-graminaceous component of comments upon the continuous sward nature the sward in selected sites above Lake of the alpine grassland, stating that only on Albina. bare rocks and snowdrift areas is there not Other palatable herbs previously much an almost alpine vegetation covering every sought after by stock include Ranunculus available spot. anemoneus, Craspedia uniflora, Leptorryn­ The deterioration process involves anum­ chus squamatus and the Geranium species ber of independent factors operating in over­ of the inter-tussock spaces of the grassland lapping sequence. These are the gradual and herbfield communities. Costin (1958) loss of palatable species, the invasion or in­ notes stock preferences for a number of creased dominance of less palatable, or more fire resistant species, the opening of the bog and fen species, particularly the dom­ sward, and the depletion of such surface inant fen species (Carex gaudichaudiana) litter and humus as remains. Indications of various other sedges and species of Astelia, deterioration and erosion of recent origin for Montia australasica, Epilobium conferti­ are reviewed by Durham (1959) and in­ folium, Ranunculus inundatus and a number clude exposed soil faces, pedestalled plants, of other short alpine herbfield species. soil and lichen lines, and humifying peats He also points to the preference of the associated with sod-tussock grassland. stock for damaged sites, further intensifying, From the writings of the workers who by local overgrazing, the deterioration of have made detai 1ed or passing examinations these communities. From an examination of of the flora (e.g. Maiden 1898, 1899: Mc­ the various major communities the construc­ Luckie and Petrie 1927: Costin 1954) and tion of deterioration patterns is possible. January, 1971 68 0'1 \0

L.£GENO

T,.\\ Alpine.. 1-ler-bfie.ld-G.-..ssla.....;l.

Sub-Aipin~ Woodland.

Sho...t ~lpi"'e. 1\e:.-bfield. ""~ 1-!ea.fh- Sh.-ub C.o....,.f'\'" n I 0 2 Beg-Fen Cornrle:><.. (,..,o..tly .,le.~e~; .. ~.,ted. 0 ::0 Snowdrift Fj .... e!d,....a..-k.. ~ Miles. ... {jae.ld,..,...~.-k (""f'"hd c.ol .. ) "' "'5­ ::0 ..... Figure 4-Vegetation patterns, Guthega catchment area 0 :l" a. Many of the changes in soil and vegetation, dominates. due to causes now removed, are reversible Within the Poa caespitosa-Celmisia and the trend toward the "climax" vegeta­ longifolia community quite distinct and sharp tion may be noted. In many other situations boundaries have been observed on freely however, the changes are irreversible unless drained slopes and reasons for their occur­ artificial soil conservation measures are also rence have been commented upon, (Costin employed. Whether changes are reversible 1954; Costin et al, 1959). Pure Celmisia or irreversible is dependent upon the degree beds frequently occur below snowpatch of deterioration, the type of community meadows where long-lying snow is the concerned and upon the delicacy of the predisposing agent (Costin et al, 1959). original balance. Beds also occur on areas of recent insta­ The pattern of deterioration of a number bility, including soil slip areas, overfalls of communities has been studied by the and disturbed areas, such as former stock author and are submitted as examples to­ camps, indicating the value of Celmisia as gether with a brief assessment. a colonizer compared with snowgrass (figure (i) Tall Alpine Herbfield (Poa caespitosa­ 5). Celmisia longifolia Association) The main features of the deterioration Two communities have been examined, pattern in this community are the loss of the first near the saddle above the Soil the inter-tussock herbs such as Craspedia, Conservation Service hut at Carruthers, and Ranunculus etc., the decrease in flowering the second on the Carruthers Ridge on the and spread of Celmisia, the opening of the catchment area of the Club Lake Creek and inter-tussock spaces allowing surface wash the following sequence constructed. and wind deflation of fine material from around tussock roots, and the smothering Poa caespitosa-Celmisia longifolia of vegetation by saltating pebble streams. (associated sub-dominant Craspedia The triggering mechanisms were selective uniflora, Haemarthria sp., Euphrasia grazing of the palatable species, burning of sp. the surface litter, and the subsequent frost, 1~ water, and wind action on the bare surface. Loss of inter-tussock species. In this community, of largest areal extent 1~ in the alpine tract, considerable natural re­ Loss of Celmisia longifolia and opening generation has taken place and it is only in of the stand. ihe most severely exposed and the most 1~ severely damaged situations that the process Poa caespitosa with up to 25 per cent is irreversible. inter-tussock spaces. Blowouts occur in more exposed situations, resulting in (ii) Short Alpine Herbfield (Plantago muel­ slight sheet erosion. leri-Montia australasica Association) Interruption at this stage usually re­ Reputedly palatable, many of these com­ sults in colonization by Acetosella munities are now truncated by rills and vulgaris and Senecio lautus and ulti­ small gullies from the snowpatch to the mate re-invasion by colonizing native communities below. Examples may be seen species. in the Upper Twynam Cirque, Club Lake ..V and in the Kunama Cirque. These areas Poa caespitosa-Epacris to 50 per regenerate rapidly when channel flow is con­ cent bare ground with associated de­ trolled. flation losses. In very exposed situa­ (iii) Valley Side Bog (Sphagnum crista­ tions such as this, deterioration is now tum-Richea continentis, S. crista­ irreversible, proceeding to the stone tum-Epacris paludosa) or erosion pavement stage, where an Two sites, located on Carruthers walking open community of fjaeldmark* species track some 450 yards from the Snowy River and 20-30 yards above the Carruthers * The erosion fjaeldmark is distinct from, and should not be confused with the true Epacris­ Creek crossing, have reg-enerated well since Veronica fjaeldmark. the removal of stock and fire and as stream

January, 1911 70 Figure 5-Natural regeneration by Celmisia longifolia of a formerly denuded and moderately eroded area, at 6,800 feet in the Carruther's Creek catchment area c:ntrenchment had not proceeded far. The In the areas where water has flowed off track, in concentrating and diverting the run­ the track, and truncated peat and gravel off water, has altered the downslope hydro­ has smothered the Sphagnum and helophyte logic conditions. The deterioration pattern communities downstream, snowpatch is related specifically to run-off, water table meadow species, among which Montia, Cal­ and aeration conditions. The following suc­ tha and Luzula are prominent, are among ce"sion occurs as free drainage increases: the primary colonizers. Several Ranuncu­ Permanently wet-Sphagnum cristatum lus species establish in fringing wet areas -Richea conti­ where the peat soils have not been gravel nentis, S. crista­ covered. turn - Epacrls paludosa Additional stages involving a number of -¥ heath-like Epacridaceae may be found to Seasonally dry-Richea continentis­ predominate under certain conditions. Epacris sp (iv) Valley Bog and Fen Complex ~ Richea continentis- Costin et al ( 1959) quote Petersen and Calorophus lateriflorus locals as evidence of the much greater form­ er extent of the valley bog complex, stating ~ that deliberate and repeated burning took Seasonally wet- Calorophus late­ riflorus - Poa place in the early 1900's and the deteriora­ caespitosa (a tive effects were most extensive following form) the 1939 bushfire. ~ Certainly no completely undamaged com­ Freely drained-Poa caespitosa. munities have been seen in the study area by

71 Soil Conservation Journal I

the author, although several of relatively due to the processes outlined above and in good vigour are present on restricted areas. marginal situations on Mount Twynam a Typical degenerated communities examined community having affinities to both the true are located at Thompson's Plain in the sub­ fjaeldmark and the snowpatch fjaeldmark alpine tract and on the low interfluve be­ is found. The latter is considered an "ero­ tween Merrit's Creek and the Snowy River sion fjaeldmark". Open communities similar some 400 yards upstream from Main Road to this, but lacking the woody Epacris, are 286. characteristic of sites where accelerated er(}­ The communities at Thompson's Plain sion has proceeded to the stone pavement show typical hummock and hollow patterns stage. These communities are, in them­ topographically oriented but consisting of selves, fairly stable, but the accelerated run­ the following species: off has. a serious deteriorative effect on the surrounding stable vegetation. HUMMOCKS HOLLOWS Richea continentis Agrostis sp. (vi) Sod Tussocl~ Grasslands Calorophus Montia This community has itself extended into lateriflorus australasica areas where formerly bog and fen communi­ Poa caespitosa ties were dominant after alteration of the Caltha introloba drainage pattern. The community has also Epacris Carexspp. undergone continued deterioration after serphyllifolia burning and grazing in the form of a general The spring fed streams of the area are thinning of the turf, the isolation of in­ entrenched and the extent of the bog and dividual plants, the entry of unpalatable fringing heath communities is much reduced. species such as Spergularia rubra, Poran­ The bog area has a surface water table only thera microphylla, and Asperula conferta, during the thaw and shrinkage cracks and and the invasion by heath species such as tunnelling beneath the peat may be noted. Kunzea muelleri and Pimelea curviflora var. Transect studies carried out on this area alpina. over a period of some ten years* since stock removal have not revealed any reversal, or (vii) Sub-Alpine Woodland even halting, of the deteriorative process. The community was originally an open or In the Merrit's Creek-Snowy River situa­ closed woodland of fantastically twisted tion, the same pattern, more severely de­ small trees near its upper limit and had, as veloped, is apparent. The streams are now the subordinate strata, a continuous grassy 3-5 feet entrenched whereas originally they sward beneath with a discontinuous shrub lacked precise definition. stratum on drier lithosolic sites. The area is today one varying from the little altered Natural regeneration in these communi­ open woodland, in the vicinity of the Kos­ ties is unlikely except in the extreme long ciusko Chalet chairlift, to the ghost forest view. Any attempt to regain the bog com­ of the Dainers Gap area, created by the 1939 munities would entail water spreading and fire and prevented from regenerating by sub­ stilling structures to eQcourage Sphagnum sequent grazing. regeneration. The snowgum (Eucalyptus niphophila) (v) Fjaeldmark is fire sensitive and a hot burn will kill even Of the two major fjaeldmark communities mature trees and may damage the ligna­ the Epacris petrophila-Veronica densifolia tubers which, especially on young seedlings, alliance (figure 6) of the exposed cols has are at or near the surface. Coppice-type extended somewhat in size at the expense regeneration from the lignotubers occurs. of the Poa caespitosa herbfield community Additionally, if bare ground occurs as a re­ * Soil Conservation Service unpublished records, sult of the fire a dense stand of pyric s'krub Cooma Office. growth may occur (Costin et al 1959;

I anuary, 1971 72 Figure 6----Fjaeldmark community of an open windswept saddle near Carruther's Peak showing the low open . J:Fpacri~- Veronica community oriented to, and growing in, the path of the prevatlmg wmd. Stable terraces may be seen in the background

Bryant, 1969 ; Hamilton and Bryant, unpub­ but except in the most rugged places it is lished). This growth includes Bossiaea covered with a dense carpet of grass and foliosa, Hovea longifolia, Phebalium ovati­ herbage and with stunted shrubs on several folium, Prostanthera cuneata and Drimys slopes." vickeriana. Where grazing has taken place the regeneration from seedling and ligna­ tuber is avidly grazed by stock resulting in Again Helms (1896) states-"Nearly complete suppression of regeneration everywhere the ground is covered with a (Bryant, 1969). dense vegetation. The valleys, fiats and slopes are covered with a compact sward Costin (1958) draws attention to the of grass . . . At the highest elevations an dramatic difference between the occasional almost alpine vegetation covers every avail­ seedling tree at Dainers Gap and the dense able spot between the rocks. A few narrow coppice growth on the adjacent water re­ stretches only do not produce the faintest serve subsequent to the 1939 fire. particle of vegetation. This occurs in places where the snow accumulates in masses on EROSION the eastern slopes--" That the extent and severity of erosion damage visible today is of recent origin is Observations in 1927 (McLuckie and apparent from the comments of early ob­ Petrie, 1927) confirm the recent origin of servers and from recent studies. erosion-"These occasional patches (snow­ patch areas) are the only area of granitic Helms (1896) comments upon the Car­ soil which, in the summertime. are not ruther's Peak area-"A few bogs are found, clothed with a dense carpet of vegetation".

73 Soil Conservation Journal These comments and observations can The current extent and severity of erosion be compared with the photographic evidence damage has been mapped by Greenup presented in figures 7 to 10. Particularly, (unpubl.) for the whole of the catchment the erosion damage in the vicinity of Car­ of the Snowy River above the proposed ruthers Peak and Mount Twynam should be Jindabyne storage, at a scale of 1:15,840. noted. It is from this area that Costin et al This survey covered the degree and extent (1959) estimated an erosion loss in the of sheet, gully, track and streambank past 50 years of more than one million erosion, and the extent of snowdrift areas tons of soil from three square miles. It would appear therefore, that severe erosion and associated areas which had become un­ damage post-dates the visits of Helms stable. Those formerly eroded areas which (1890, 1893, 1896) to the summit area, had been stabilized and revegetated were although it is fairly certa\in that vegetal mapped and have been adjusted to include deterioration had, by this time, commenced. areas treated since completion of the survey. Studies by CSIRO* on buried peat beds That portion of the survey covering the on the sediment filled cirque above Blue Guthega Dam catchment, an area of 22,976 Lake, using radioactive carbon techniques, acres (35.9 square miles) is reproduced in have dated the uppermost bed as of approxi­ figure 12. The detailed mapping criteria mately ninety years of age. This bed is are given in table II whilst the areas in each buried beneath 6-12 inches of silt and individual sub-catchment so classified, are granitic gravel derived from the severely presented in table Ill. The location of the eroded camping reserve above. sub-catchments and the distribution of * A. B. Costin, CSIRO, pers. comm. erosion is illustrated in figures 11 and 12. TABLE 11 EROSION CLASSIFICATION CRITERIA*

:symbol Percent Soil Indicators Erosion Class Bare Area Loss-inches

s SHEET EROSION So Negligible .. . . 10% 3" sl Slight...... 25% 3"-6" Pedestalled plants. s. Moderate .. . . 26-75% 6"-9" Pedestalled plants, exposed rocks. ------G GULLY EROSION Go Negligible .. .. Rilling sparse less than 3" deep. G1 Slight ...... 12" G, Moderate .. .. 12"-36" Gs Severe .. . . >36" ------T TRACK EROSION Tt 1"-3" Rilling due to water concentration. T, 4"-12" Ts >12" ------SD SNOW PATCH Rilling and sheeting associated with margins of snowdrift area.

* After Greenup (unpubl.)

January, 1971 74 ====------~~------~--==~===~~-=------=-======~~

TABLE .JII

AREAS AFFECTED BY EROSION WITIDN GUTHEGA CATCHMENT AREA-ACRES

Sheet Erosion Area Snow No. Sub-Catchment name Area of I Catchment! Treatedt Patches Nil Slight I Moderate I Severe I .. 1* Guthega River .. .. 2,030 1,910 105 2.0 15 2 Pounds Creek .. .. 2,000 1,010 770 80 15 2.0 125 3 Twynam Creek . . . . 970 475 350 95 10 .. 40 4 Blue Lake Creek .. 1,720 627 650 200 143 102.9 100 5 Club Lake Creek .. 1,810 788 695 195 12 0.5 120 6 Upper Snowy River .. 1,485 510 770 80 5 7.0 120 7 Merrit's Creek .. .. 2,500 1,645 740 40 5 4.0 70 8 Charlotte Pass .. .. 1,765 1,645 120 9 Wright's Creek .. .. 745 450 245 5 5 40 10 Trapyard Creek .. .. 840 430 395 15 11 Bett's Creek .. .. 2,240 1,580 620 20 15 5

12 Upper Spencer's Creek .. ~)10 353 155 2 13 Spencer's Creek .. .. 1,390 1,020 350 20 14 Illawong Lodge .. .. 535 465 70 15 Blue Cow Creek .. .. 1,460 845 570 45 ------­ ---­ --­ ---­ ---­ ---­ ---­ ---­ TOTALS .. 22,000t 13,753 6,605 777 210 118.4 655

* Location of the sub-catchments is indicated in figure 11. t Actual area is 22,976 acres based on S.M.A. survey. t Not included in catchment area and erosion class figures.

From this information it is apparent that are completely bare (e.g., Mount Twynam) the catchments of the left-hand tributaries where soil, to a depth of several feet, has of the Snowy have suffered more extensive, been removed. In this section Greenup re­ and more severe damage than have the ports that deterioration of moderately and right-hand tributaries and that the erosion severely sheet eroded areas is continuing damage is predominantly sheet erosion. though possibly more slowly than has pre­ Damage from advanced ( S2 and S3) sheet viously been the case. Gully erosion appears erosion in a concentrated form over appre­ ciable areas is confined to the highest confined to the three situations of tracks, country of the region and is particularly in and around damaged snowpatch outflow noticeable along the saddles and upper areas, and former camping reserves, while slopes between the North Ramshead and incipient gullying is present on severely sheet Mount Tate. In many cases several acres eroded areas.

75 Soil Conservation Journal Figure 7--Sheet erosion in open sub-alpine woodland near Dainer's Gap. Note the exposure of roots and pedestalling of plants after soil removal by erosion

Figure 8--Truncation of a buried peat overlain by 30 inches of A1pine Humus soil by concentrated run-off from an erosion pavement area above. This occurred during the 1964-65 summer January, 1971 76 Fit?ure 9'----

Figure 10'----

77 Soil Conservation Journal I

0

Miles Figure 11-Gutbega catchment area, showing location of sub-catchment areas. The numbers refer to the sub-catchments listed in table iii

~ Nllgligib/tl .shut erosion______c=J Minor sheet ,eroslon______bd Moderate sht-et erosion ______!IIII] Severe shut erosion ______f22:.Z] Snowpatches______------­ Stabilized art2as __ _ ------~ Fire damaged areas------~ MILE:S ~I /

Figure 12-Erosion damage in Guthega catchment area. (After Greenup, unpubl.) January, 1971 78 DISCUSSION the upward spread to about the 5,000 feet The relation between those areas most contour. severely eroded and the interplay of the In attempting to understand the causes of physical environment and former land use is deterioration and erosion within the Snowy most striking. Immediately apparent are the Mountains, a number of studies have been interrelations between the area of greatest undertaken by CSIRO, this Service and climatic severity, the main range access track other bodies vitally interested in the area. and stock route, and the apparent spread of erosion damage outwards and downwards Studies in soils and vegetation, undertaken from the upper slopes of the main range. by the author, on the Nungar High Plain, a Add to this the apparent recency of the large frost valley having an altitudinal range damage, the increased regularity and in­ between 4,400 and 4,800 feet and typical of tensity of grazing, initially under the areas perhaps 1,000 feet higher, have proven influence of a series of drought years (1896­ illuminating. 1903), the increased frequency of the use Examination of seedling regeneration of fire as a management tool and the nett under mature snowgum woodland, of mean result is sheet erosion damage of a severity age 85 ± 15 years, showed dense regenera­ requiring "artificial remedial measures" over tion during four years protection from graz­ 987 acres of the most vulnerable and valu­ ing. The reintroduction of grazing initiated able country in the catchment area. Vegeta­ a progressive ?ecrease in. t~~ nun;tbers of tion has been shown to have deteriorated surviving seedlmgs whose m1ttal he1ght had over most of the summit area within the been less than three feet. Seedling trees tenancy of European man. taller than three feet escaped grazing. The native and naturalized fauna have frequently been blamed for much of the ero­ Fire either wild or controlled, destroyed sion damage and vegetal deterioration. saplings of at least 10 feet in height. Sub­ Firstly it should be noted that prior to the sequent grazing effectively suppressed re­ advent of European man the faunal com­ growth of survivors (Bryant, in press). ponent had been part of the stable eco­ Similarly, at Long Plain in the Upper system. If they now contribute to the degra­ Murrumbidgee, a comparison over a four­ dation of soil and vegetation it is logical teen-year period (Bryant, 1969) has to state that the effects are "man-induced". resulted in a definite reduction in seedlings In fact the wallabies, kangaroos, and wom­ being established .under grazing, ~hilst l?ro­ bats no more than marginally inhabit the tection from grazmg has resulted 111 a shght roof top of our continent above the treeline. increase in numbers. Similarly much denudation has been In studies of the effect of grazing and blamed upon the case moth, yet long term fire upon open and closed swards of snow­ quadrat studies* have shown damage to be grass and various herbaceous and shrubby localized and regeneration, in the absence constituents (Bryant unpubl.), grazing has of fire and grazing, to be rapid under the resulted in a decrease in the inter-tussock protective plant mulch. species on both closed and open swards. The cosmopolitan pest, the European rab­ On closed swards grazing over seven bit introduced with the settlement of Aus­ seasons has resulted in the opening of the tr~lia by European man has assisted in the sward, whilst the effect of a fire of only devastation of pastoral lands over much of moderate intensity reduced ground cover Australia, but has had little effect in the by an average of 30 per cent and regenera­ Guthega catchment area. The combination tion under grazing after two years was only of low palatability and low nutritive value 60-70 per cent of that protected fr~m graz­ of the snowgrass, extended snow cover and in~. On open swards a defimte and severity of winter temperatures has limited persistent decline in ground cover under *Soil Conse,rvation Service, Cooma (unpubl. grazing has been established (Bryant data), "Case Moth Studies". unpubl.).

79 troll Conservation 1ourntrl These results highlight the severe de­ summer grazing of sheep and cattle. Large teriorative effect grazing and fire combined areas of snowgum have been converted to can have, even within a four-year period, on dense pyric scrub, or replaced by disclimax this class of country. They support the grassland and heath. Grassland and herb­ contention that catchment efficiency for field communities generally have been water yield and snow lease grazing manage­ opened up, and ground water areas partly ment are incompatible, and that-"the dried out following the development of alpine ecosystems are not well adapted to creeks and gullies through them. Slight to human interference and have mostly under­ moderate soil deterioration is widespread. gone deterioration due to the recent These conditions can be extended or activities of European man" (Costin et al., reduced, depending on the degree of con­ 1959). trol of fires and grazing". To successfully reclaim these deteriorated In conclusion the recent statement of a and eroded areas, and others in a similar noted alpine ecologist ls here worth quoting condition within the Snowy Mountains, (Costin, 1967)-"Most of the plant com­ detailed investigation and reclamation pro­ munities have been modified by burning and grammes are currently in operation.

References Beadle, N. C. W., and Costin, A. B. (1952)-Ecological Classification and Nomenclature. Proc. Linn. Soc. N.S.W. 77 (1-2). Browne, W. G., and Valiance, T. G. (1963)-Further Notes on Glaciation in the Kosciusko Region. Proc. Linn. Soc. N.S.W. 88 (112-129). Bryant, W. G. (1969)-Vegetation and Ground Cover Trends-Following the Exclusion of Stock at Three Sites in the Snowy Mountains, New South Wales. Journ. Soil Cons. N.S.W. 25 (183-198). Bryant, W. G. (in press)-Gra:r.ing, Burning, and Tree Seedling Regeneration in Eucalyptus pauciflora Woodlands, Snowy Mountains, New South Wales. Journ. Soil Cons. N.S.W. Bryant, W. G. (in prep'n)-The EfJe·i:t of Grazinf? and Burning on a Mountaln Grassland, Snowy Mountains, New South Wales. Costin, A. B. (1954)-A Study of the Ecosystems of the Monaro Region of N.S.W. N.S.W. Government Printer, . Costin, A. B. (1957)-The High Mountain Vegetation of Australia. Aust. J. Bot. 5: (2) (173). Costin, A. B. (1958)-The Grazing Factor and the Maintenance of Catchment Values in the Australian Alps. CSIRO Div. PI. Ind. TIP No. 10. Costin, A. B. (1961)--Scienti{ic Aspects of the Proposed Kosciusko Primitive Area. Aust. J. Sci. 23 (397). . Costin, A. B. (1967)-Management Opportunities in Australian High Mountain Catchments. In "Intern. Syrup. on For. Hydrology" (eds. Soper and Lull) :Permagon PresG, Oxford and NY: 565-77. Costin, A. B., Hallsworth, E. G., and Woof, Mari.on (1952)-Studies in Pedogenesis in N.S.W. -Ill The Alpine Humus Soils. Soil Sci. 3: (2) (190). Costin, A. B., Wimbush, D. J., Kerr, D., and Gray, L. W. (1959)-Studies in Catchment Hydrology in the Australian Alps-] Trends in Soils and Vegetation. CSIRO Div. PI. Ind. TIP. No. 13. Durham, L. J. (1959)-Indicators of Land Deterioration in the Snowy Mountains Catchments. Journ. Soil Cons. N.S.W. 15 (251), 15 (333 ). Galla way, R. W. (1963 )-Glaciation in the Snowy Mountains-A Re-appraisal. Proc. Linn. Soc. N.S.W. 88 (180~198).

January, 1911 80