A phytosociological analysis and description of wetland vegetation and ecological factors associated with locations of high mortality for the 2010-11 Rift Valley fever outbreak in South Africa
Fig 5
Categorization of five, freshwater wetland depressions-types with descriptions of vegetation and ecology. A. Deelpan, a typical saline endorheic pan, with narrow, the dense vegetated pan-margin, providing ideal breeding habitat for Aedes. Aa. Holpan, a non-saline pan, covered with Eragrostis bicolor the low, caespitose, specialist arid-region grass. B. De Dam, shallow depression wetland with clay soil and emerging sedge Fuirena coerulescens, grass Echinochloa colona and fern, Marisela capensis. Bb. Petrusburg wetland with large-tufted Scirpoides dioecious, emerging Cyperus laevigatus sedges, and the spreading, prostrate forb Hypertelis salsoloides. C. Mature ox-bow cut-off, 100cm deep, with wetland vegetation, sedges, grasses, on the margins. Cc. Inundated ox-bow wetland-type at Bougainvillea, a site of high sheep mortality during the 2010 outbreak. D. Riet River in flood, near Mokala National Park, with dense, monotypic stands of Phragmites australis. Dd. Seven Dams had no RVF mortalities. The most species-rich wetlands with extensive stands of Phragmites australis (foreground) and Typha capensis. E. Sedge and Juncus dominated wetland. The deep grove is created by the wheel of the pivot irrigator. Ee, Extensive, spill-over wetland created at Rooibokpan near Jacobsdal, dominated sedges, Juncus and OBL forbs in the <50 cm deep water.