Structural and floristic classifications of Cape Mountain Fynbos on Rooiberg , southern Cape

Structure and floristic com position o f the plant cover were used to establish separate classifications o f plant com ­ munities in M ountain Fynbos on Rooiberg, South Africa. The structural units and floristic associations closely correlate with each other and their distribution reflects the major environm ental influences, aspect and altitude. It is concluded that, despite the preliminary character o f the survey, resource inventories o f this type are suitable as a foundation for park management.


IN T R O D U C T IO N
At the request o f the Departm ent o f Forestry, the first author carried out a survey o f the False Macchia (Acocks, 1975) or M ountain Fynbos vegetation of the Rooiberg M ountain C atchm ent Area to provide basic data for a m anagem ent plan (Taylor, in press).For this purpose, a simple classification, description and m ap were needed, dividing the vegetation into units that are visually hom ogeneous in physiognomy.Because these units had to be recognized by nonbotanical personnel, it was decided to adopt a struc tural classification, rather than a floristic one.The structural survey was done by m arking units of more or less uniform vegetation structure and terrain m or phology on air photos (scale 1:20 000).These units were then studied in the field.In about a m onth's field work, sufficient inform ation was gathered to delineate eight m ajor structural units and 20 varia tions, all o f which could be related to habitat.These have been m apped (1:50 000) and described in detail by Taylor (in press).
M anagem ent o f M ountain Fynbos reserves such as Rooiberg aims at m aximum production of clear water from catchm ents and the m aintenance of vege tation diversity both in plant species and plant life forms.Hence, a vegetation study for m anagement purposes should include both a floristic and a struc tural description.Time did not permit an extensive phytosociological survey on Rooiberg.However, to determ ine whether the m ajor structural units could also be distinguished by their species com position, a brief Braun-Blanquet survey was carried out.Twenty-eight releves were laid out subjectively within stands o f vegetation th at were regarded as represen tative o f the m ain structural units.In the phytosocio logical table only vascular plants were taken into account.This paper summarizes and compares the results o f the structural and floristic surveys.For in form ation on the flora and phytogeography of R ooi berg we refer to Taylor (1979).

L O C A T IO N A N D H A B IT A T
A bout 20 km south-east o f Ladismith, Cape P ro vince (Fig. 1), lies a west-east trending m ountain range, divided into more or less equal sections by the G ouritz River.The Rooiberg M ountain Catchm ent A rea, 25 345 ha in extent, comprises a large part o f the higher western section of this range at approxi mately 33°40'S latitude and 21°30'E longitude.It consists o f State and private land, m anaged by the Departm ent o f W ater A ffairs, Forestry and E nviron m ental C onservation for the conservation o f water, flora and wild life.
The range is one o f a series o f isolated m ountains located between M ontagu and Uniondale, the fynbos o f each m ountain being separated from that o f its neighbours by karroid lowland vegetation o f the Little K arroo.
Geomorphologically, the Rooiberg Range is a broad anticlinal fold o f Table M ountain Sandstone strata, breached near the top o f the arch.The breach has eroded to form a series of deeply incised kloofs that run parallel to the main crest before breaking south in deep gorges that have cut through subsidiary crests.The Table M ountain Sandstones are inter rupted by a shale band that can be traced as a sinuous line across the north side of the range.Sandy lithosols cover the greater part o f the reserve.Rock o u t crops and cliffs are com m on in the interior kloofs but the main north-and south-facing sides of the range are not excessively steep.
The climate is hot and dry.Situated on the transi tion between the winter-and summer-rainfall areas, Rooiberg receives only the outer fringe o f the winter cyclonic rains and few' summer thunderstorm s.The mean total precipitation for 1977/1978 (the first year after rain gauges were erected) was about 365 mm, the northern side of the m ountain receiving about half as much rain as the southern slopes (P.B. Odendaal, pers. comm.).Probably the most effective pre cipitation is from condensation o f the clouds that form around the high peaks.Considerable tem pera ture and m oisture differences may be expected be tween crests (about 1 400 m altitude) and footslopes o f the m ountain (about 800 m).
V EG E TA T IO N

Structural units
The vegetation units identified in the structural survey depict only gross structural characteristics.They are based on simple criteria such as estim ated height and canopy cover o f the vegetation and esti m ated proportion o f (i) restioid, (ii) narrow-leaved and (iii) proteoid com ponents.These com ponents characterize fynbos vegetation.For convenience, their definitions are repeated here, (i) Restioid refers to hemicryptophytic plants o f the family Restionaceae with sclerophyllous tubular stems and leaves that have been reduced to m em branous, non photosynthetic scales or small sheaths arising singly from each node.They are often tufted but sometimes rhizom atous.The category includes plants in other families that have a physiognomy similar to the Restionaceae, for example, most Tetraria and Ficinia species, some Juncus species and Typha.(ii) Narrow leaved means the very narrow leptophylls, usually sclerophyllous though some may be fleshy or even succulent.It includes flat, involute and cylindrical leaves as well as revolute leaves like those o f the Ericaceae.The term had to be substituted for 'ericoid' which is now restricted to revolute sclerophyllous leptophylls.(iii) Proteoid is the term for plants with leaves and growth form resembling proteas.They have isobilateral leaves with the shape and texture o f a typical protea e.g.Protea lorifolia, P. repens or broader leaves like P. nitida and P. cynaroides.Broad-leaved is used here to denote the roughly ovate, sclerophyllous leathery leaves of woody shrubs derived from the northern floras as against those o f typical fynbos plants (e.g.Cassine, Maytenus, Euclea).
The vegetation units appeared to be suitable m ap ping units.W here local aspect m ight significantly affect the vegetation and therefore the management, variations were distinguished within the m ajor struc tural units.In our description the following letters have been used: N = com m unities on slopes of northerly aspects, S = com m unities on southerly aspects, C = communities o f crests and K = com munities o f very steep kloofs.Relative positions of the communities on Rooiberg are shown in Fig. 2.

Communities with northerly aspects
Community NJ.This com m unity, comprising Variations N la, N ib , C l, C2, is found on the m oderately steep upper and m iddle slopes (1370-1060 m) to the north o f the divide.The vegeta tion is a closed restioid and narrow-leaved shrubland in which the former element is often predom inant or at least conspicuous.Variation N la o f the highlands east o f Rooiberg Peak is mainly restioid and about 0,5-1 m high (Fig. 3).Most o f the precipitation in this area comes from the condensation of clouds formed by the summer south-east winds.The land is privately owned and was probably burned fairly fre quently in the past.
Variation C l (Fig. 4) occurs on summits and is stunted because o f its exposed site.It is sometimes dom inated by grasses.Many of the localities, too small to be m apped separately, have been included in Variation C2 which occurs along the crest and m ajor spurs at high altitude.This variation has a higher species diversity and greater variety in dominance and height of species due to many local differences in aspect and degree o f slope (Fig. 5).Since the m ajor fire belts are sited on ridges, the Variations C l and C2, like N 1 a, have been subject to m ore frequent and regular burning than other parts o f the reserve.lorifolia) increases in height (up to 2 m) and cover (up to 75%) (Fig. 6).Leucadendron salignum extends in a broad belt across the middle slopes, giving them a yellow-green speckled appearance.At the middle altitudinal limit o f this variation is a similar belt of the grey-leaved small tree, Protea nitida (W aboom ) which, though less widespread than Leucadendron salignum, often overlaps its range.This 'W aboomveld' is recognizeable on air photos but is too restric ted in area to map separately.

Com munity N2.
Including Variations NE and NW , this com m unity occurs between about 1 300 and 650 m on steep northerly slopes beneath the second crest (Fig. 7).These lower slopes receive less cloud m oisture and are therefore warmer and drier than those of Variation N la, north o f the divide.Narrow-leaved shrubs exceed restioids in cover while proteoids are rare and o f a more xerom orphic type, like Protea lorifolia.The com m unity contains a fair num ber o f succulents and grasses although their cover is not high.Sites with north-east and north west aspects are separated as Variations NE and NW respectively.The narrow-leaved shrub Passerina vulgaris tends to dom inate on both aspects and Protea punctata occurs locally on upper slopes in variation NE.
Community N3.This com m unity is found between 1 060 and 900 m on the plateau or shelf on the nor thern side of the m ountain below Variation N ib .Slopes are gentle to alm ost level and very stony.The vegetation, about one metre in height, is character ized by the predom inance o f narrow-leaved shrubs in the upper canopy (Fig. 8).In lower layers, restioids, grasses and succulents (mainly M esembryanthem aceae) can be quite num erous.
At the western limit o f the range or at the outer edge of the plateau where less rain falls, elements o f Renosterveld, especially the Renosterbos (Elytropappus rhinocerotis), become conspicuous.C om m unity N4.This com m unity occurs on steep north-facing slopes between 900 and 700 m, below Com m unity N3 down to the base o f the m ountain.The soils are very stony, shallow and dry.Like the previous one, Com m unity N4 is dom inated by narrow -leaved shrubs (Fig. 9) but the vegetation is more open and poorer in species content, containing some karroid elements and more succulents than usual in fynbos because this com m unity borders on the karroid vegetation o f the lowlands.

Com munity K N (including Community K).
The main drainage o f upper Rooiberg comprises four complex kloof systems that occupy the rift south of the divide.In their upper reaches the kloofs run parallel to the divide and then drain south.The north side o f the range is drained by five large kloofs run ning east or north-east and a series o f shorter, shal lower kloofs running n o rth.Com m unity KN is found at lower levels o f all the southw ard draining kloofs.
The habitat is a very steep to precipitous rock slope with some soil accum ulated in pockets and bands bet ween the vertical cliffs (Figs 7 & 10).The kloofs draining north or north-east have no distinct north or south aspects, but the vegetation of their steep sides, Com m unity K, appears structurally similar to that o f C om m unity KN.In both communities the canopy cover is low (about 25-70% ) and consists o f scat tered shrubs with a rounded growth form 1-2 m in diam eter, interspersed with coarse restioids and grasses, some broad-leaved bushes of tropical affini ty (e.g.D iospyros dichrophylla and Cussonia spicata) and succulents in the ground layer.Proteoids are usually absent.The vegetation, like the habitat, is very similar to N4.

Communities with southerly aspects
Com munity SI.This community, which includes Variations S W and SE, is found on m oderately steep SOUTHERN CAPE to very steep southerly slopes from 1 490 m down to about 630 m.The well drained, shallow soil consists o f fine grey humic sand with some leaf litter.At high elevations, these slopes receive m oisture condensed from the clouds that form in the south-east wind, therefore reducing the effect o f the hot, dry sum mers.The vegetation is dense shrubland with a closed, uniform canopy of proteoids up to 2 m high.
There is at least one lower layer o f restioids and narrow-leaved shrubs similar in structure to the canopy o f Community N la.
W ithin Com munity SI there are several structural variations, possibly resulting from differing proteoid dom inance: at the highest, steepest sites, Protea punctata occurs in almost pure stands with some Leucadendron comosum (Fig. 11); at middle altitudes Leucadendron eucalyptifolium becomes either dom inant or co-dom inant with Protea punc tata.At still lower elevations, the num ber o f proteoid species increases with the addition of Protea eximia and P. neriifolia but their total cover decreases until at the lowest parts the proteoid layer contributes about 50% canopy cover and is only about 1 m high, while the restioid and narrow-leaved layer becomes closed.Since these structural variations either form mosaics or intergrade with each other, they cannot be m apped separately at the 1: 50 000 scale.Variations SW and SE, with western and eastern aspects respec tively, are m appable units o f the open proteoid com munity o f lower altitudes down to about 400 m, which include Protea re pens, P. lorifolia and Leucadendron salignum.Grasses are also more fre quent in these variations than in the other variations o f Com m unity SI.
Community 52.This com m unity was found only in a small area on the steep upper south-easterly slopes o f the peak m arked by Trigonom etrical Survey beacon No. 149.Stands on sim ilar sites on the highest peaks, which possibly belong to the same com m unity, have been affected by a fire belt.Shallow, black, humic soil, m ore moist than other Rooiberg soils, occurs between the bands o f outcrop-    ping bedrock.The vegetation is a dense, narrow leaved shrubland up to 1,5 m tall in which species indicating moist conditions, like Berzelia intermedia and Psoralea pinnata, are prom inent (Fig. 12).Near the lower limit some tall proteoid and restioid com ponents (Protea punctata and Cannamois virgata) occur.

Community S3
. This community has a wide distri bution from the third crest of the range down to the foot of the m ountain and along its entire length.The gentle to m oderate southerly slopes have dry, sandy lithosols.In the west, the slope becomes steep, with bands o f kranses (cliffs) interspersed with colluvial boulders.The vegetation varies in height and cover but is generally less dense than that o f Communities SI and S2.Floristically and structurally, Community S3 is probably the most diverse o f all the Rooiberg vegetation types.Leucadendron salignum, the only constant feature, occurs virtually everywhere.Com munity S3a o f the upper slopes between 915 and about 760 m has a fairly dense mixed proteoid vegetation with the highest concentration o f proteoid species in the reserve; the understorey is chiefly restioid.A belt of W aboomveld, with Protea nitida conspicuous, extends along the middle slopes from about 760 m to 640 m (Community S3b); narrow leaved shrubs predom inate and grasses are fairly fre quent (Fig. 13).Along the lowest slopes, especially to the west, is a zone o f karroid narrow-leaved shrubs (e.g.Pteronia, Relhania) about 1,5 m high con stituting up to 75% canopy cover, in which the coarse tufted grass Merxmuellera arundinacea is often con spicuous (Community S3c.)

Floristic units
We have sampled the vegetation by means of Braun-Blanquet releves (Table 1) varying in size from the usual 50 m2 to about 100 m2, 200 m2 or 300 m2 depending on differing vegetation structure.Some units, like SI, are undersam pled, the rare ones like S2, KN & N2 are not sampled at all, while others have been sampled more intensively because of their special interest, e.g. the Protea wY/cto-dominated W aboom veld which occurs in different floristic sub divisions throughout the range of M ountain Fynbos.

C O M P A R IS O N OF ST R U C T U R A L A N D FLO RISTIC U N IT S
A com parison o f the structural and floristic units is summarized in Fig. 2 & Table 2.

Com munity I.
O f the lower northern slopes this com m unity comprises all releves in structural units N3 and N4.Predom inant growth forms include re stio id s (R estio fru tic o su s, T ham nochortus argenteus, Hypodiscus striatus) and narrow-leaved shrubs (Felicia filifolia, Passerina vulgaris).The first three releves of this com m unity are located in struc tural unit N4 which, it was noted, is poorer in species than N3.In fact, Releves 475 and 485 have the lowest species content o f any in the survey.
Releve 448 has no Protea nitida and few other d if ferential species.It would seem that within C om m unity II the species-rich W aboom stands are, in special situations, part of a wider-ranging vegetation type that lacks Protea nitida and is in general less rich in species content.This hypothesis might have im por tant management im plications and can only be tested by more sampling.Releve 442 is the only one in W aboomveld on the northern side o f the m ountain.It occurs at a considerably higher altitude than any of the releves on the south side.Alm ost two decades ago Taylor (1963) observed that Protea nitida 'does seem to occur at higher altitudes on the northern slopes', probably to com pensate for the hotter and drier con ditions found there.
Community III.This com m unity comprises releves situated on summits and the crest fire-belt (structural units C l & C2), burnt just less than four years before the survey.Predom inant life forms include narrow leaved shrubs (Centella virgata, Aspalathus rubens, Selago brevifolia) and restioids (Restio cuspidatus, R. fruticosus).The three summit releves, Releves 474, 430 and 222 all show high scores for the grass Pentaschistis eriostoma; Ehrharta ramosa and Pen taschistis colorata also occur in the community.Releve 439 is particularly poor in differential species.It may represent a related but undersam pled com munity.Within C om m unity III, this releve is the only one not situated on the main crest and that has vegetation over 1 m in height, suggesting that it may lie outside the four-year old firebelt.
Community IV.This com m unity comprises two subcommunities, a and b, m ainly distinguished from each other by the presence in IVb o f an overstorey of proteoids (Protea punctata, Leucadendron spp.) and the fact that IVa has no differential species.Subcom munity IVb occurs on upper southern slopes bearing the proteoid structural unit S I.In Subcommunity IVa two releves (432, 434) are on upper north-facing slopes bearing the restioid structural unit N la; one (405) is on a spur (C2) and one ( 472) is on a summit (C l).Therefore three structural units appear to be combined in one floristic group.On the other hand, one structural unit (C l) has three releves (474, 430 & 222) in floristic Com m unity III and one (472) in IVa.The data are insufficient to determ ine whether these anomalies are due to fire-age or other habitat factors.They may merely show that structural units N la , C l and C2 are not distinct entities.
Table 1 indicates that stands of lower and middle slopes, bearing the structural units N3, N4 and S3 (floristic Com m unities I, I and II respectively) are floristically m ore related to each other than to any of the other stands.The same appears to apply to stands o f crests and upper slopes bearing the structural units N1 and SI (floristic Com munities III + IVa and IVb respectively).
The results from the structural and floristic surveys indicate that structure and species composition of the vegetation are related to m ajor habitat factors like altitude and aspect.

C O N C L U D IN G REM ARK S
Both in the structural and the floristic surveys, we have sampled only the m ajor m atrix o f fynbos com munities and not the detailed patterns.Our results are therefore provisional.
The floristic survey, even a brief one like that on Rooiberg, supported and supplem ented the struc tural survey.The latter can be done without extensive a priori knowledge o f the complex fynbos flora, and has the advantage of being quicker and the data can be used by personnel with little botanical training.Emphasis is not on the plant species but rather on its functional adaptation to the environm ent.The struc turally hom ogeneous units will be characterized by particular life and growth forms and can be expected to react in a reasonably uniform way to treatment such as burning, and to use such as grazing by game.The structural classification will therefore help managers to delineate m anagement units, to deter mine rotation lengths and stocking rates, to m aintain balanced, natural ecosystems and to m onitor physiognomic changes.
In the floristic survey, emphasis is on species com position o f the plant cover, and the ecological am plitudes of plant species are used to describe plant com m unities and their interrelationships.The floristic classification will indicate which species and communities are threatened, and will provide infor m ation on how to conserve them and how to m ain tain species diversity.
In conclusion, we think that a com bination of a structural and floristic survey, as we have described, is a necessary and suitable basis for fynbos conserva tion managem ent.

A C K N O W LE D G M EN T S
For help in organizing and carrying out field work we are grateful to Forester P. Weinberg o f Ladismith and a num ber o f our colleagues and friends.We are deeply indebted to Mr C. Boucher o f the Botanical Research Unit, Stellenbosch for his assistance in the com puting program for Table 1.

UITTREKSEL Die struktuur en floristiese samestelling van die plantegroei is gebruik vir die daarstelling van afsonderlike klassifikasies van plantgemeenskappe in Bergfynbos op Rooiberg, Suid-Afrika. Die str.>kturele eenhede en floristiese assosiasies is sterk met mekaar gekorreleer en hulle verspreiding weerspieel die vernaamste omgewingsfaktore, nl. aspek en hoogte bo seespieel. Ten spyte van die voorlopige aard van die opname, is die gevolgtrekking dat hulpbronopnames van hierdie aard 'n geskikte grondslag vorm vir die bestuur van natuurlike gebiede.
com p osition o f the plant cover were used to establish separate classifications o f plant co m m unities in M ountain Fynbos on Rooiberg, South A frica.The structural units and floristic associations closely correlate with each other and their distribution reflects the m ajor environm ental influences, aspect and altitude.It is concluded that, despite the preliminary character o f the survey, resource inventories o f this type are suitable as a foun d ation for park m anagem ent.
Variation N ib , less frequently burnt, represents vegetation o f northerly aspects west of Rooiberg Peak and below Variations C l and C2.Low narrow-

FF
i g .5 .-Variation C 2 o f C om m unity N1 on the spur run ning north-w est from R ooi berg Peak to Taays Rand.The vegetation is restioid with P r o te a e x im ia in th e right foreground.In and be yond the shadow is a patch o f dense proteoid shrubland on a local southerly slope.SOUTHERN CAPE leaved shrubs prevail, but at middle altitudes the proteoid element (Protea repens, P. eximia, P.

F
i g .7 .-T he second crest sh ow ing C om m unity N 2 between the sk y lin e and the steep c l i f f s .V a r ia t io n N E the darker patch at top left, and C om m unity KN on the preci pitous low er slopes.

F
i g .9 .-Com m u n ity N 4 on the steep north-facin g basal slope.

Fig
Fig. 10.-N orth-facing krans on the left with vestiges o f C om m unity KN at its base.G orge o f the so u th -flo w in g Bosrivier.

F
i g . 1 1 .-Tall d en se p ro teo id shrubland o f C om m unity SI dom inated by Protea punctata with a fringe o f P. eximia in front, bordering on a fire-belt in th e fo r e g r o u n d w h ere restioids and narrow-leaved shrubs o f the lower layer are prom inent.