Abstract
Road verges in the Prince Albert district, South Africa were examined to determine whether they are important refugia for plant species in the Karoo biome. Vascular plants at 50 sites on road verges were compared with those plant communities in the adjacent grazed rangelands. Verges were found to support a greater mean number of species, total plant cover, and number of individual plants. Road verges were found to contain 11 unique species compared with 20 unique species in rangelands. Plant community composition varied with more forbs and succulents on the verge and more shrubs in the rangeland. Significantly greater cover of unpalatable plants was found on the ungrazed road verge, and no difference in palatable and highly palatable plant cover was recorded, indicating that herbivory is not a major driver in defining community differences in these environments. No significant differences in soil moisture or texture were found between verge and rangeland. We argue that road maintenance and construction activities have an over-riding controlling influence on road verge community composition. Although it is not possible to discount the possibility that road verges provide an important refuge for certain species, it appears that they are disturbed environments that do not contribute significantly to the plant conservation needs of this biome.
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References
M. Begon J.L. Harper C.R. Townsend (1996) Ecology Blackwell Science Ltd. Oxford
A.F. Bennett (1991) Roads, roadsides and wildlife conservation: a review D.A. Saunders R.J. Hobbs (Eds) Nature Conservation 2: The Role of Corridors Surrey Beatty & Sons Chipping Norton, NSW, Australia
W.R.J. Dean S.J. Milton (1991) ArticleTitleDisturbance in semi-arid shrubland and arid grasslands in the KarooSouth Africa: mammal diggings as germination sites Afr. J. Ecol. 29 11–16
W.R.J. Dean S.J. Milton (1995) ArticleTitlePlant and invertebrate assemblages on old fields in the arid southern KarooSouth Africa Afr. J. Ecol. 33 1–13
P.C.V. du Toit (1995) ArticleTitleThe grazing index method of range condition assessment Afr. J. Range For. Sci. 12 61–67
du Toit P.C.V., Botha W. van D., Blom C.D., Becker H.R., Olivier D.J., Meyer E.M. and Barnard G.Z.J. 1995. Estimating grazing index values for Karoo plants. Department of Agriculture Technical Communication 239, Pretoria.
K.J. Esler R.M. Cowling (1995) ArticleTitleThe comparison of selected life-history characteristics of the Mesembryanthema species occurring on and off Mima-like mounds (heuweltjies) in semi arid southern Africa Vegetatio 116 41–50
K.J. Esler N. Phillips (1994) ArticleTitleExperimental effects of water stress on semi-arid Karoo seedlings: implications for field seedling survivorship J. Arid Environ. 26 325–337 Occurrence Handle10.1006/jare.1994.1035
R.T.T. Forman (2000) ArticleTitleEstimate of the area affected ecologically by the road system in the United States Conserv. Biol. 14 IssueID1 31–35
R.T.T. Forman L. Alexander (1998) ArticleTitleRoads and their major ecological effects Annu. Rev. Ecol. Syst. 29 207–231 Occurrence Handle10.1146/annurev.ecolsys.29.1.207
J.L. Gelbard J. Belnap (2003) ArticleTitleRoads as conduits for exotic plant invasions in a semiarid landscape Conserv. Biol. 17 IssueID2 420–432 Occurrence Handle10.1046/j.1523-1739.2003.01408.x
Gwala P.P., Drennan P.M. and van Staden J. 1991. Factors affecting the germination of seeds of Atriplex Lindleyi South African Association of Botanists and Phycological Society of Southern Africa. Annual Congress, University of Natal.
A.V. Hall (1987) ArticleTitleThreatened plants in the Fynbos and Karoo Biomes, South Africa Biol. Conserv. 40 29–52 Occurrence Handle10.1016/0006-3207(87)90011-5
J.K. Hibberd T.L. Soutberg (1991) Roadside reserve condition 1977–1989 in the Southern Tableands of New South Wales D.A. Saunders R.J. Hobbs (Eds) Nature Conservation 2: The Role of Corridors Surrey Beatty & Sons Chipping Norton, NSW, Australia
C. Hilton-Taylor E. Moll (1986) ArticleTitleThe Karoo – A Neglected Biome Veld Flora 72 33–36
R.J. Hobbs L.F. Huenneke (1992) ArticleTitleDisturbancediversity, and invasion: implications for conservation Conserv. Biol. 6 324–337 Occurrence Handle10.1046/j.1523-1739.1992.06030324.x
M.T. Hoffman R.M. Cowling (1990) ArticleTitleDesertification in the Lower Sundays River Valley, South Africa J. Arid Environ. 19 105–117
B.R. Lamont V.A. Whitten E.T.F. Witkowski R.G. Rees N.J. Enright (1994) ArticleTitleRegional and local (road verge) effects on size and fecundity in Banksia menziesii Aust. J. Ecol. 19 197–205
A.B. Low A.G. Rebelo (1996) Vegetation of South AfricaLesotho and Swaziland Department of Environmental Affairs and Tourism Pretoria
B. McCune J.B. Grace (2002) Analysis of Ecological Communities MjM Software Design Oregon
P. Milberg B.B. Lamont (1995) ArticleTitleFire enhanced weed invasion of roadside vegetation in south-western Australia Biol. Conserv. 73 45–49 Occurrence Handle10.1016/0006-3207(95)90061-6
S.J. Milton (1992) ArticleTitleEffects of rainfall, competition and grazing on flowering of Tripteris sinuatum (Asteraceae) in arid Karoo rangeland J. Grassland Soc. S. Afr. 9 158–164
S.J. Milton (1995) ArticleTitleEffects of rainfall, sheep and tehritid flies on seed production of two arid Karoo shrubs in South Africa J. Appl. Ecol. 32 137–144
S.J. Milton W.R.J. Dean G.I.H. Kerley (1992) ArticleTitleTierberg Karoo Research Centre: history, physical environmentflora and fauna Trans. R. Soc. S. Afr. 48 15–46
S.J. Milton T. Wiegand (2001) How grazing turns rare seedling recruitment events to non-events in arid environments S.W. Breckle M. Veste W. Wucherer (Eds) Sustainable Land-Use in Deserts Springer Heidelberg 197–207
K.A. Moloney S.A. Levin (1996) ArticleTitleThe effects of disturbance architecture on landscape level population dynamics Ecology 77 375–394
T.G. O’Connor (1995) ArticleTitleTransformation of a savanna grassland by drought and grazing Afr. J. Range For. Sci. 12 53–60
S.W. Todd M.T. Hoffmann (1998) ArticleTitleA fence-line contrast reveals effects of heavy grazing on plant diversity and community composition in NamaqualandSouth Africa J. Plant Ecol. 142 169–178
S.C. Trombulak C.A. Frissell (2000) ArticleTitleReview of ecological effects of roads on terrestrial and aquatic communities Conserv. Biol. 14 IssueID1 18–30 Occurrence Handle10.1046/j.1523-1739.2000.99084.x
J.W. Way (1977) ArticleTitleRoadside verges and conservation in Britain: a review Biol. Conserv. 12 65–74 Occurrence Handle10.1016/0006-3207(77)90058-1
M.J.A. Werger (1985) The Karoo and southern Kalahari M. Evenari I. Noy-Meir D.W. Goodall (Eds) Hot Deserts and Arid Shrublands, Vol. 12B. Ecosystems of the World Elsevier Amsterdam 293
M.V. Wilson A. Shmida (1984) ArticleTitleMeasuring Beta diversity with presence absence data J. Ecol. 72 1055–1064
J.H. Zar (1984) Biostatistical Analysis EditionNumber2 Prentice-Hall New Jersey
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O’FARRELL, P.J., MILTON, S.J. Road Verge and Rangeland Plant Communities in the Southern Karoo: Exploring What Influences Diversity, Dominance and Cover. Biodivers Conserv 15, 921–938 (2006). https://doi.org/10.1007/s10531-004-3102-9
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DOI: https://doi.org/10.1007/s10531-004-3102-9