Cederberg vegetation and flora

87 Pages·1996·7.3 MB·English

by  Taylor, H. C.

Cederberg
vegetation
and
flora
TRELITZIA
3
Digitized by the Internet Archive
2016
in
https://archive.org/details/cederbergvegetat03tayl
R E L I T Z I A 3
Cederberg
and
vegetation
flora
by
H.C. TAYLOR
Formerlyofthe Botanical Research Institute
Presentaddress: 9 Dorries Drive, Simon'sTown 7995
Scientific Editor: O.A. Leistner
Technical Editor: B.A. Momberg
NASIONALE BOTANIESE
INSTITUUT
rtiva'O t>«Sj X101 PRETORIA0001
.497 -!0- 2.1
X101 rRETORiA 0091
NATIONAL uTANICAL
Botanical I.NS. T.I•.TUTE
INSTITUTE
2CussoniaAve,Brummeria,Pretoria
PrivateBagXI01,0001 Pretoria
ISBN 1-874907-28-5
1996
R E L T Z A
I I
This is the third occasional publication ofthe National Botanical
InstitutetoappearundertheseriesnameStrelitzia.Thenewseries
hasreplacedMemoirsoftheBotanicalSurveyofSouthAfricaand
AnnalsofKirstenboschBotanicGardenswhichtheNBIinherited
from its predecessororganizations.
ThegenusStrelitziaoccursnaturallyineasternsouthernAfrica. It
comprisesthree arborescentspecies, known as wildbananas, and
two acaulescent species, known as crane flowers orbird-of-para-
dise flowers. ThelogooftheNational BotanicalInstituteisbased
on the striking inflorescence ofStrelitzia reginae, a native ofthe
Eastern Cape and KwaZulu-Natal that has become a garden
favourite worldwide. It symbolizes the commitment of the Na-
tional Botanical Institute to provide the facilities, knowledge and
expertise necessary to ensure the conservation, sustained use,
appreciation and enjoyment ofSouth Africa’s exceptionally rich
floraand vegetation.
Cover: The northernCederberg (Groenberg 181) lookingeasttowardthe
TanquaKaroo, 1986-03-05.
ISBN 1-874907-28-5
©Publishedbyandobtainablefrom:NationalBotanicalInstitute,PrivateBagX101,Pretoria0001,
SouthAfrica.Typesetting:S.S.Brink(NBI).Reproductionandprintingby:AuroraPrinters,P.O.
Box422,Pretoria0001.Tel.[phone].
Contents
ABSTRACT
1
UITTREKSEL
1
INTRODUCTION
1. 3
2.PHYSICALENVIRONMENTANDHISTORICALPERSPECTIVE,by H.C.TAYLOR, D.P. BANDS &
J.C. SCHEEPERS 5
Topographyandgeomorphology 5
Soils 7
Climate 7
Landuseandthebiota 8
Historyofvegetationdescription 9
3. FLORISTICCLASSIFICATIONOFTHENORTHERNCEDERBERG 11
Introduction 11
Methodsofsamplingandsynthesis 11
Classification 12
Theplantcommunities 12
A. Thicketoffire-protectedkloofsandscrees(Communities 1-4) 14
1. Riverkloofs(Communities 1 &2) 14
2. Screeandsand(Communities3 &4) 15
B. Fynbosofwell-drainedhabitats(Communities5-19) 16
1. Rocky habitats(Communities5-16) 17
1.1. Non-colluvialrockslopesandplatforms(Communities5-12) 17
1.2.Colluvialrockslopes(Communities 13-15) 23
1.3.High-altituderockslopes(Community 16) 25
2. Sandyhabitats(Communities 17-19) 25
C.Fynbosofpoorlydrainedhabitats(Communities20-26) 29
1. Mid-altitudeplateauxandterraces(Communities20-24) 29
1.1.Winter-wethabitats(Communities20-23) 29
1.2. Permanentlymoisthabitats(Community24) 32
2. Summitplatforms(Communities25,26) 33
Discussionandconclusions 34
Method 34
ThestructuralclassificationofCampbell (1985) 34
Habitat-floristicrelationshipswithinthestudyarea 35
Comparisonwithotherregions 35
Bioticinfluences 36
4.FLORISTICANALYSIS 37
Introduction 37
Comparisonofthreelocalfloras 37
FamilyandgenussequencesintheCederberg 38
Conclusions 40
ACKNOWLEDGEMENTS 41
REFERENCES 43
CHECKLIST 47
APPENDICES 63
Clanwilliam cedar, Widdringtonia cedarbergensis about 8 m tall, growing on typical ‘rock turrets’
in the Welbedacht area.
(SfixRELITZIA 3 (1996)
1
Abstract
AsanintroductiontoastudyofthevegetationoftheCederberg,animportantcatchmentinthedriernorthernpart
ofthe Western Cape, the geology, physiography, soils, climate, land use, biota and historical background are
described.Thediscussionprovidesabroadcontextualandenvironmentalframeworkforthesubsequentvegetation
classification.
InthevegetationstudyofthenorthernCederberg,theBraun-Blanquetmethodofsamplingandanalysisrevealed
26plantcommunitiesintwomajorstructuralandchorologicalunits,thicketandfynbos.Thicketoccursonsitesthat
provide natural protection from fire; fynbos is found in fire-prone habitats. Soil drainage appears to be the
fundamental factorseparatingfynboson well-drainedslopesfrom fynboson level sites with impededdrainage.
Furthersubdivisionscorrelatedwithsoilorigin,depth,rockinessandaltitudeshowthatthefloristichierarchyiswell
correlatedwithenvironmentalfactors.Standarddescriptionsofeachcommunityprovideasynopsisofvegetation
structure andfloristics, environmental influences andspecial features. Therelationshipsbetween vegetation and
habitatareillustratedbydiagrams,photographsandaphytosociologicaltable.
Floristicanalysis,andcomparisonwithtwomountainflorasinthesouthwesternCape(CapeHangklipareaandCape
ofGoodHopeNature Reserve),reveal thattheCederberg florahas linksnotonly withthefynbosoftheCape
FloristicRegionbutalsowiththedrywinterrainshrublandofNamaqualandandthewesternKaroo.Thechecklist
ofthevascularplantsintheCederbergWildernessandMountainCatchmentArea,recordsatotalof1 778species.
Uittreksel
Asinleidingtot’nstudievandieplantegroeivandieCederberg,'nbelangrike opvanggebiedindiedroernoordelike
deelvandieWes-Kaap,worddiegeologie,fisiografie,gronde,klimaat,bodembenutting,biotaengeskiedkundige
agtergrondbeskryf.Hierdiebesprekingverskaf'nbreekontekstueleenomgewingsraamwerkvirdiedaaropvolgende
plantegroeiklassifikasie.
DeurtoepassingvandieBraun-Blanquet-tegniekopdieplantegroeivandienoordelikeCederberg,word’n totaal
van26plantgemeenskappeintweehoofstruktureleen-chorologieseeenhedeerken:ruigteenfynbos.Ruigtekom
vooropplekkewatnatuurlikebeskermingteenbrandbied,terwylfynbosopplekkegevindwordwataanbrand
blootgestelis.Diefynbosplantgemeenskappewordeerstensopgrondvangronddreineringverdeelinfynbosteen
goedgedreineerde hellingsen die opgelyktes metbelemmerde dreinering. Verdereonderverdelingstoon datdie
floristiesehierargiegoedgekorreleerismetomgewingsfaktoresoosgrondoorsprongen-diepte,rotsagtigheiden
hoogteboseevlak.
Standaardbeskrywings van elke plantgemeenskap verskaf'n oorsig van plantegroeistruktuuren floristieseeien-
skappe,omgewingsinvloedeenspesialekenmerke.Dieverhoudingstussenplantegroeienhabitatworddeurmiddel
vandiagramme,foto’sen’nfitososiologiesetabelgeillustreer.
DiefloristieseanaliseenvergelykingmettweebergflorasindieSuidwes-Kaap(KaapHangklip-gebiedenKaapdie
GoeieHoopNatuurreservaat)toondatdieCederbergfloranienetmetdiefynbosvandieKaapseFloristieseStreek
skakelnie, maarookmetdiedroewinterreenstruikveldvanNamakwalandendiewestelikekaroo, 'nTotaal van
1 778spesiesvaatplantewatindieCederberg-wildemis-enbergopvanggebiedvoorkom,wordgelys.

d?TRELITZIA 3 (1996) 3
1. Introduction
The Cederberg* lies east of the towns of Clanwil- these derive management principles appropriate to each
liam and Citrusdal in the Olifants River valley, be- unit.
tween latitudes 32°00’ and 32°45’ south and longitudes
18°50’ and 19°25’ east. The range is about 90 km long Accordingly, proposals for a semi-detailed phytoso-
and 25 km wide at its widest point near the middle. It ciological survey of selected mountain catchments
is traversed by three roads: the main road from Clan- were made (Taylor 1980, 1981) and adopted by the
william over Pakhuis Pass in the north, a secondary Forestry authorities. Campbell (1983, 1985, 1986a &
road from Clanwilliam to Ceres in the central part, and b) has produced a primary survey of mountain fynbos
the main road between Citrusdal and Ceres which for the whole Fynbos Biome using a classification
crosses a narrow sector in the southern part. based mainly on structural attributes ofthe vegetation.
Campbell's important work will be discussed in Chap-
Most of the vegetation is mountain fynbos but taesrse3s.smHeonwtevsetrud,ieass(aMufloluenrda1t9i8o3n)ftohrerdeetraeimlaeidnsreasonuerecde
Karoo elements penetrate the deep valleys ofthe tribu- for more detailed surveys which will provide an in-
taries ofthe Doring River on the east side and, on the ventory of all species within each plant community. A
west, a karroid zone extends southward from Clanwil- trial of survey methods in the Cape of Good Hope
liam into the valleys of the Jan Dissels and Rondegat Nature Reserve in 1969 (Taylor 1984a & b) led to the
Rivers.
adoption of a floristic method based on the Ziirich-
Montpellier approach described by Mueller-Dombois
The mountain fynbos of the Capensis Region (Tay- & Ellenberg (1974) and Werger (1974).
lor 1978; Kruger 1979a), the Cape Floristic Region
(Kruger 1979b) orthe Fynbos Biome (Campbell 1985), Plant community studies in mountain fynbos have
with its exceptionally rich flora and high degree of hitherto been concentrated in the south-western, south-
endemism (Hall 1981), is in urgent need of carefully ern and eastern parts ofthe Capensis Region, e.g.Bond
planned conservation management and development. (1981), Cowling (1984), Van Wilgen & Kruger (1985)
The Cape floral kingdom is home to many useful herbs and Boucher (1988). The north—western e—xtension of
and medicinal plants, and its showy components, es- Acocks’s (1988) Veld Type 69 Fynbos has been
pecially the Proteaceae, are the mainstay of an impor- largely neglec—ted despite the presence of three major
tant wildflower industry (Davis 1990). Man's impact State Fo—rests Hawequas, Groot Winterhoek and Ce-
on this rich and diverse flora has been severe. Only derberg and their adjoining mountain catchments.
39% of its former area remains and fynbos now has Surveys of Swartboschkloof (McDonald 1988) and in
the highest concentration of threatened plants of any the Langeberg (McDonald 1993a, b & c) have been
temperate region (Hall 1980; Hilton-Taylor in press). completed.
Introduced woody plants have invaded and displaced
the wild vegetation on a large scale (Taylor 1969; Hall The veld types survey of South Africa by Acocks
& Boucher 1977). The conservation of mountain fyn- (1988), based on land potential, provided the first sig-
bos is therefore of high priority, not only on account nificant classification of vegetation for land use plan-
of its water- and soil-holding capacity but also for its ning in this country on a broad landscape scale. For
scientific importance, aesthetic appeal, recreational detailed planning and management within veld types,
value and economic potential. But sound conservation more precise methods have been adopted.
must be based on informed management, and the first
sotfepcoinmmiunnfiortmyindgatmaanoabgtearisneids tforopmrovpihdyetoasofcrioalmoegwiocrakl The Cederberg is the home ofseveral rare, endemic
surveys (Taylor 1962, 1963). The phytosociologist, in orcommercially exploitable plants. The endemic Clan-
analysing, describing and classifying plant communi- william cedar, Widdringtonia cedarbergensis, has been
ties, creates the hierarchy of vegetation units and in- felled for sawtimber for over two centuries (Smith
dicates the relationship of these units to one another 1955), but studies on the effect ofthis exploitation and
and to their habitats. The experimental researcher and on the autecology of the species only began during
autecologist must subsequently provide an under- this decade (Manders 1985). The mountain range
standing of the dynamic processes involved, and from forms the catchment of two rivers that irrigate arid
lands both toeast and west. By nature ofits wild, spec-
tacular scenery it has great potential recreational value
*MiTnhiestseprelolfinNgat‘iCoendaelrbEedrugc’awtaiosnap(pnroowveMdinoinst3errdoAfprAirlt,s,19C8u1l,tubrye,thSec(itehnecne) (Ackerman 1972, 1979), and because it lies close to
andTechnology)ontherecommendationoftheNational Place Names the northern boundary ofthe Cape Floristic Region its
Commission. vegetation is of special scientific interest. The Ceder-
4 d?TRELITZIA 3 (1996)
FIGURE 1.—Map of
the study area
inthenorthern
Cederberg.
berg has been under State control for over a hundred claimed in terms of the Mountain Catchment Act No.
years (Andrag 1977) and its management has posed 63 of 1970 and currently managed by the Department
problems to conservationists ever since, yet there has ofNature andEnvironmental Conservation ofthe Cape
been no detailed floristic survey of the vegetation of Provincial Administration. This area comprises 67 000
the area. ha of Forest Reserve that was already protected at the
time of proclamation, and 59 000 ha of adjoining pri-
The Cederberg is, moreover, a proclaimed Wi—lder- vately owned land. Most of the State land, 64 400 ha
ness Area(Ackerman 1972; 1979; Van Zyl 1974) one according to Erasmus (1984), was proclaimed a Wil-
of the first in South Africa. It is essential, therefore, derness Areaby Government Notices in 1973 and 1976
that the Ce-derberg should be managed as a ‘shop win- (Bands 1978). The boundaries ofthe Wilderness Area,
dow’ where professionalism of conservation manage- non-Wilderness State Forest and the Mountain Catch-
ment is evident to its many visitors so that its status ment Area are shown on the 1:50 000 Cederberg map
as true wilderness will be assured for the future. To compiled by the Chief Director of Surveys and Map-
this end, the phytosociological study of the Cederberg ping.
was undertaken, firstly to inform conservation manag-
ers on the habitats and plant communities in theircare, After a reconnaissance of the whole MCA in 1985
and secondly to contribute data on a little-known cate- it was decided, for practical reasons, to limit the semi-
gory of fynbos to the inventory of plant communities detailed survey to the northern and northeastern part
in South Africa (Scheepers 1983). ofthe Cederberg (Figure 1) including the cedar regen-
eration study sites in the Welbedacht-Wolfberg area.
This study was originally planned to cover the whole Data gathering began in January 1986 and was com-
oftheCederberg Mountain Catchment Area (MCA) pro- pleted towards the end of 1987.