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Scientific Name | Polygonum snijmaniae S.Ortiz |
Higher Classification | Dicotyledons |
Family | POLYGONACEAE |
National Status |
Status and Criteria | Endangered A4ace; B1ab(iii,v)+2ab(iii,v) |
Assessment Date | 2021/03/25 |
Assessor(s) | P.C.V. Van Wyk & H. Mtshali |
Justification | This species is rare occurring on dunes in the Richtersveld region, of the Northern Cape, South Africa. It has a restricted distribution range, with an extent of occurrence (EOO) of 56-333 km², and an area of occupancy (AOO) of 12-20 km². It is known from between 3 and 5 locations. Population decline of 30-40% has been observed to take place over the past 15 years due to drought and overgrazing by livestock. Population decline of between 20 and 30% is suspected to take place 2050, given predicted increases in temperature and aridity for the region (generation length 15 years). It therefore qualifies for listing as Endangered under criteria A and B. |
Distribution |
Endemism | South African endemic |
Provincial distribution | Northern Cape |
Range | This species has a very limited distribution range and is endemic to the Richtersveld, in the Northern Cape, South Africa. |
Habitat and Ecology |
Major system | Terrestrial |
Major habitats | Richtersveld Red Duneveld, Southern Richtersveld Yellow Duneveld |
Description | It is confined to sand dunes. |
Threats |
| It has lost between 30 and 40% of its population to the impacts of an extended drought which started in 2015 and is still ongoing at the time of assessment. Its habitat has also been degraded by overgrazing and trampling by livestock. Predictions of future climate change include further increases in annual average temperature of between 1.4°C and 2.4°C by 2050 (van Wilgen and Herbst 2017), which will result in ongoing decline to the population a further decline of 20-30% is expected by 2050. |
Population |
This rare endemic is known from few localities in the Richtersveld area. Recent field observations recorded this species in at least three locations, Gemsbokvlei, Port Nolloth and Richtersveld National Park. There are records from the late 1990s from Korridor farm (near Kamma se Berg) on the north of Richtersveld National Park, but this species has not been relocated in this area.
The subpopulation in Klein Duin is stable, occurring on a dune that is well protected inside the national park, and has approximately 500 individuals.
The subpopulation in the north-east of Port Nolloth has about 200 individuals and it occurs on a very young dunes that are mobile, making the establishment of plants difficult.
The Gemsbokvlei subpopulation occur on a private farm and municipal land, the population on these dunes consists of about 1000 individuals and is threatened by severe grazing and the impact of drought.
Population decline is currently taking place as a result of habitat degradation and drought. Monitoring during 2021 at Gemsbokvlei and Klein Dune noted many dead plants with at least 50% of the population having died. Ongoing monitoring is needed.
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Population trend | Decreasing |
Bibliography |
Snijman, D.A. 2013. Plants of the Greater Cape Floristic Region 2: The extra Cape flora. Strelitzia 30. South African National Biodiversity Institute, Pretoria.
Van Wilgen, N.J. and Herbst, M. 2017. Taking stock of parks in a changing world: The SANParks Global Environmental Change Assessment. SANParks, Cape Town.
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Citation |
| Van Wyk, P.C.V. & Mtshali, H. 2021. Polygonum snijmaniae S.Ortiz. National Assessment: Red List of South African Plants version . Accessed on 2024/12/07 |
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