Hex River Arid Alluvium Fynbos

Hex River Arid Alluvium Fynbos is a critically endangered vegetation type that is restricted to the floor of Hex River Valley, reaching as far as De Wet near Worcester. It may be considered a subtype of Breede Alluvium Fynbos. The altitude mostly ranges between 200 and 350 m, with some patches reaching higher.

The landscape features undulating plains and alluvial fans and streams.

The vegetation is a relatively tall shrub mixture with graminoid (grassy) understorey. Asteraceous and proteoid fynbos dominant, with localised restioid fynbos. Succulent and Renosterveld elements not uncommon.

The soil is alluvial deposits consisting of rounded cobbles in loamy sand over sediments of the Malmesbury and Bokkeveld shales.

The area receives 480 mm rain on average, mostly in winter. Frost infrequent. Well fed with water from mountains.

Important Taxa

The riverine portions support Metrosideros angustifolia, Searsia angustifolia, Restio paniculatus, Diospyros glabra and Freylinia lanceolata. The areas away from the rivers support Anthospermum spathulatum, Searsia dissecta, Seriphium sp., Struthiola ciliata, Passerina sp., Muraltia spinosa, Willdenowia incurvata, Helichrysum moeserianum, Montinia caryophyllacea, Protea laurifolia, Aspalathus rugosa, A. acuminata, A. biflora, Leucadendron barkerae, Cliffortia crenata, C. ruscifolia, Restio capensis, Euryops tenuissimus, Cephalophyllum sp. and Antimima sp.

Endemic Taxa

Unknown.

Conservation

Critically endangered. Only a few patches have not been transformed by vine cultivation and urban development. Riverine areas seriously invaded by Acacia mearnsii (black wattle) and Eucalyptus sp. (blue gum), and Casuarina sp. (beefwood).

References

• Helme, N. A. 2007. Botanical report: Fine scale vegetation mapping in the Upper Breede River Valley. Report for CapeNature, as part of the C.A.P.E. programme.
• Mucina, L., Rutherford, M.C. 2006. The vegetation of South Africa, Lesotho and Swaziland. Strelitzia 19.