Volume 95, November 2014, Pages 19–23
Livestock paths on Namaqualand quartz fields: Will the endemic flora disappear?
Highlights
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- Livestock paths on Namaqualand quartz field vegetation had low soil stability.
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- Stable soils on quartz fields supported vegetation with greater diversity.
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- Endemic dwarf succulents were affected by livestock paths.
Abstract
Quartz
fields are rare features that contribute significantly to vegetation
diversity and endemism of South Africa's Succulent Karoo Biome. The
Riethuis-Wallekraal quartz fields in the north-western Namaqualand area
of South Africa contain 17 quartz field specialist species of which
seven are endemic to this specific area. Hoof-action by livestock has
formed paths of approximately 0.30 m on these quartz fields. It would be
important to conservationists to understand whether direct (e.g.
trampling) and indirect effects (e.g. burial of flora by sediment
movement) associated with the livestock paths holds any threat to the
dwarf succulent (< 0.05 m) and micro-chamaephytes (0.06–0.15 m)
endemic to the quartz fields. We tested the hypotheses that the unique
quartz field vegetation and biological soil crusts would be affected by
loose soil particles transported downslope from the paths. The soil
stability index, total vegetation cover, cover of specialized quartz
field species and species diversity were lower on livestock paths but
did not differ between upslope and downslope locations. Livestock paths
also had lower cover and fewer quartz field specialist species. It is
concluded that under conditions of intense and continuous grazing,
livestock are likely to have an even stronger negative impact on the
specialist quartz field flora.
Keywords
- Succulent Karoo;
- Endemic species;
- Soil stability;
- Livestock paths
- Corresponding author at: P.O. Box 1379, Sedgefield 6573, South Africa. Tel.:
+ 27 72 252 8129.
Copyright © 2014 South African Association of Botanists. Published by Elsevier B.V. All rights reserved.
