Landscape sensitivity and ecological change in western Zambia: The long‐term perspective from dambo cut‐and‐fill sediments

Abstract

A series of small, shallow seasonally, or interannually, waterlogged depressions (dambos) in the upper Zambezi Valley in western Zambia hold shallow peat deposits and are bounded on their western margin by sandy lunette dunes. Using luminescence dating of sands, fossil pollen analyses and the macrocharcoal record from cored peat, the long‐term stability of these landforms and the vegetation they now support is investigated at a site east of the upper Zambezi. Although the upper lunette dune sediments accumulated between 14 ± 2 and 6 ± 1 ka, the onset of peat accumulation and preservation within the dambo did not occur until 2800 cal a BP, suggesting that only from this point onwards were conditions stable and wet enough year‐round to allow the formation and preservation of peat during this time. Results from this study indicate that the long‐term behaviour of the dambo conforms to a cut‐and‐fill dynamic, where under more arid conditions the dambo becomes a dry pan, providing a sediment source for the adjacent lunette dune. In contrast, during wetter times, when the dambo holds surface water year‐round, it becomes an organic‐rich sediment repository preserving a fossil pollen record of long‐term vegetation change.

Automatic Detection of Open and Vegetated Water Bodies Using Sentinel 1 to Map African Malaria Vector Mosquito Breeding Habitats

“…Tributaries from the surrounding landscape enter the floodplain and run along the fringes of the escarpment on fine muddy deposits converted into rice paddies. Several of these tributaries are supplied by small shallow waterlogged depressions that form on peat deposits elevated above the Barotse floodplain, known as 'dambos' [69]. Connectivity of the floodplain to these surface flows and also subsurface flows through the floodplain plays an important role in surface water dynamics [70].…”

Tropical Wetland (TropWet) Mapping Tool: The Automatic Detection of Open and Vegetated Waterbodies in Google Earth Engine for Tropical Wetlands

“…The local geology in Barotseland is sedimentary, overlain by Kalahari sand, and localised silty alluvium within the floodplain [46]. Resistant basalt at the lower reaches of the floodplain causes the narrowing of the valley and the progression of seasonal backwaters upstream during peak flow conditions [47]. Dambos (waterlogged depressions) are situated predominately on the eastern escarpment of the floodplain.…”

“…Dambos (waterlogged depressions) are situated predominately on the eastern escarpment of the floodplain. These pluvially fed features drain into the floodplain and tend to remain partially inundated during the dry season [47]. Floodplain vegetation is predominantly grassland and represents an important area for livestock rearing [47].…”

“…These pluvially fed features drain into the floodplain and tend to remain partially inundated during the dry season [47]. Floodplain vegetation is predominantly grassland and represents an important area for livestock rearing [47]. The region has a number of public health challenges including human nutrition, diseases like malaria, and access to health facilitates during periods of flooding [8].…”

Geographically extensive larval surveys reveal an unexpected scarcity of primary vector mosquitoes in a region of persistent malaria transmission in western Zambia

“…East of the Barotse oodplain, aquatic habitats in the narrower Lui valley zone are also formed by local, not Zambezi, ooding [25,26], with human settlements concentrated along the valley edge. The dambo zone too is found largely to the east of the Barotse oodplain: dambos are shallow depressions, lined with organic sediments (often peat), which are seasonally or permanently waterlogged, forming an important dry season water source for closely associated human settlements [27,28].…”