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The Vankervelsvlei mire has one of the thickest peat deposits (more than 10 m) in South Africa, which started accumulating before 7000 BP. Two previous studies on the hydrological system that sustains the wetland reached inconsistent conclusions and disagreed strongly on the main sources of water feeding the wetland. One suggested that the wetland is fed by groundwater discharging from the underlying Table Mountain Group Aquifer, while the other proposed that the wetland is a perched system fed only by precipitation water. We tried to reconcile these discrepancies by measuring water table, hydraulic pressure and temperature in the peat profile and analysing the ionic composition of the groundwater. We also carried out radiocarbon dating (14C) of groundwater and surface water. Our results showed that both groundwater and surface water are relatively young (

The physical and hydrological properties of peat from seven peatlands in northern Maputaland (South Africa) were investigated and related to the degradation processes of peatlands in different hydrogeomorphic settings. The selected peatlands are representative of typical hydrogeomorphic settings and different stages of human modification from natural to severely degraded. Nineteen transects (141 soil corings in total) were examined in order to describe peat properties typical of the distinct hydrogeomorphic settings. We studied degree of decomposition, organic matter content, bulk density, water retention, saturated hydraulic conductivity and hydrophobicity of the peats. From these properties we derived pore size distribution, unsaturated hydraulic conductivity and maximum capillary rise. We found that, after drainage, degradation advances faster in peatlands containing wood peat than in peatlands containing radicell peat. Eucalyptus plantations in catchment areas are especially threatening to peatlands in seeps, interdune depressions and unchannelled valley bottoms. All peatlands and their recharge areas require wise management, especially valley-bottom peatlands with swamp forest vegetation. Blocking drainage ditches is indispensable as a first step towards achieving the restoration of drained peatland areas, and further measures may be necessary to enhance the distribution of water. The sensitive swamp forest ecosystems should be given conservation priority.

Matlabas is a mountain mire in Marakele National Park, located within the headwaters of the Limpopo River in South Africa. This mire consists of a complex of valley-bottom and seepage wetlands with small elevated peat domes. The occurrence of one decaying peat dome, which has burnt, and desiccated wetland areas with terrestrial vegetation has raised concerns. The aim of this study was to understand the mire features and water flows in order to identify the potential drivers causing wetland degradation. Wells and piezometers were installed to monitor the hydraulic head and collect water samples for analysis of ion composition, 18O and 2H stable isotope content, and δ13C and 14C isotope content for radiocarbon dating. Moreover, peat temperature profiles were measured and peat deposits were also dated using radiocarbon. Results indicate that the Matlabas mire developed in the lowest central-east side of the valley by paludification at the onset of the Holocene. During the Mid-Holocene, peat development was extended laterally by autogenic and allogenic processes. Three types of water flows driving peat development were identified – sheet flow, phreatic groundwater flow and deep groundwater flow – two of which are surface or near surface flows. The recent occurrence of decaying peat domes and desiccated wetland areas is possibly related to loss of exfiltrating deep groundwater flows that have resulted from drainage by the head-cut channels in the mire and interception of near surface water flow by an access road, respectively. Interventions should be undertaken to prevent further degradation of the mire. Significance: This study is the first, as far as we are aware, on the ecohydrology of an inland mountainous mire in southern Africa. The results highlight the importance of the current wetland management (including rehabilitation) initiatives in South Africa. The integrative ecohydrological methods can be applied in other headwater wetlands in southern Africa.

South Africa has a limited number of peatlands and most of them are relatively small compared to those in cooler temperate regions in the northern hemisphere. We gathered 40 basal peat samples representative of South Africa’s peatlands to explore their development during the Late Pleistocene and Holocene. Depth profiles of nine of them were also investigated using radiocarbon dating, which yielded information on past environmental changes affecting South African peatlands. The data showed three peaks in the frequency of peatland initiation, which are consistent with available climatic and sea level fluctuation data: one after the Last Glacial Maximum (LGM) and two during the Mid to Late Holocene. Inland peatlands in mountain valleys showed optimal growing conditions during the glacial-interglacial transition, continuing until the Early-Holocene. This is due to the switch to the wet and warm interglacial climate. In contrast, coastal peatlands showed optimal initiation conditions over two phases during the Holocene, which is consistent with sea level rise peaks that led to optimal moist conditions occurring ca. 6,000–3,000 and 1,000 years ago. Sea level rise reduced groundwater drainage, which led to a rise in the primary groundwater table. However, data from some of the coastal peatlands indicate independence from the sea level fluctuation, and that they are rather controlled by climatic conditions and their local hydrogeomorphic setting, e.g. perched groundwater aquifers. Some peatland complexes show a pattern of phased initiation with peat initiation consistent with altitude difference, which could be due to a positive feedback of blocking caused by peat accumulation in lower reaches, reducing groundwater drainage to the sea.

The Rugezi Marsh is an extensive peatland located in a mountain valley in the north of Rwanda. It is being groundwater fed and is therefore a fen with a rich biodiversity. An IUCN endangered listed orchid species, Disa stairsii, occurs in the system as well as three Bryophytes: Lycopodiella cernua, Sphagnum cuspidatum and S. perichaetiale. Sphagnum perichaetiale is a new species recorded for Rwanda. The peatland has been degraded by diverse activities, such as draining, cultivation, and roads crossing the wetland. Uncontrolled burning regimes due to agriculture, as well as over-exploitation of non-timber forest and wetland products further impact the system. Consequently these activities have led to the lowering of the water table, peat desiccation and establishment of terrestrial invasive vegetation species. Local communities and Rwanda at large are dependent on this wetland for various goods and services ranging from production of fibre, fodder, protein to water supply and hydroelectricity. Conservation and proper management of the wetland, including sustainable restoration measures, are therefore of importance.

The scarcity of peatlands and mires in Namibia is well known. Peatlands have been found in the north, which is the wettest part of the country. In the 1930s, spring mires were reported by German geologists in the Waterberg area, which also has relatively high annual precipitation. This short note reports some field observations and a literature search for old documents that mention the occurrence of springs and spring mires in the Waterberg region. The search was done by IMCG members who visited the Waterberg area in August 2014. We found springs, but no real mires. However, we found remnants of what might have been a large spring mire similar to that reported by the German geologist Paul Range, who found “local spring mires (Quellmoore) with a peat thickness of several metres in northern South-West Africa”. Whether or not our peat remnants were situated at the same site as the Range discovery could not be assessed. We compared the landscape position of the peat remnants and spring in the Waterberg area of Namibia with information from an ongoing ecohydrological study in the Waterberg area of Limpopo Province, South Africa.