Swartland Alluvium Fynbos

Description

Distribution: Western Cape Province: Swartland lowlands at west-facing piedmonts of the Groot Winterhoekberge near Porterville, Saronberg, Elandskloofberge to the Limietberge near Wellington; broad valley bottoms of the Paarl, Drakenstein, Franschhoek and Banhoek Valleys, with some extensions west of Paarl Mountain and to Klapmuts. Altitude 60–250 m, rarely reaching 350 m. 3.7% of this vegetation type occurs within and 96.3% outside the City. Lower rates of transformation occurred nationally (73%) than inside City borders (95%).

Vegetation & Landscape Features: Moderately undulating plains, adjacent mountains and in river basins. The vegetation is a matrix of low, evergreen shrubland with emergent sparse, moderately tall shrubs and a conspicuous graminoid layer. Proteoid, restioid and asteraceous fynbos types are dominant, with closed-scrub fynbos common along the river courses. Ericaceous and restioid fynbos found in seeps.

Geology & Soils: Alluvial gravel and cobble fields typically resting over Malmesbury Group schists and phyllites (in the northern part of the area) as well as over Cape Suite granites (in Drakenstein Valley from Wellington to Franschhoek) and on Malmesbury Group sandstones from Simondium to Klipheuwel.

Climate: Seasonal, winter-rainfall regime, peaking from May to August. MAP (mean: 655 mm) varies broadly from 320–980 mm (close to foot of mountains). Mean daily maximum and minimum temperatures 29.5°C and 6.0°C for February and July, respectively. Frost an infrequent phenomenon. This is the wettest and hottest alluvium fynbos type.

Endemic Taxa: Low Shrubs: Diastella buekii, Erica alexandri, E. bakeri, Marasmodes duemmeri, M. undulata, Phylica stenopetala, Protea mucronifolia. Succulent Shrub: Lampranthus schlechteri. Geophytic Herbs: Brunsvigia elandsmontana, Bulbine monophylla, Geissorhiza furva, Moraea villosa subsp. elandsmontana, Watsonia dubia.

Conservation: Critically endangered. Target 30%. Nearly 10% conserved in the Waterval Nature Reserve, Winterhoek (mountain catchment area) and private reserves such as Elandsberg, Langerug and Wiesenhof Wildpark. More than 75% already transformed for vineyards, olive orchards, pine plantations, urban settlements and by building of the Voëlvlei and Wemmershoek Dams. Alien Acacia saligna and Hakea sericea are prominent in places.

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