Taxonomy
Scientific Name
Cynanchum zeyheri Schltr.
Higher Classification
Dicotyledons
Family
APOCYNACEAE
National Status
Status and Criteria
Vulnerable B2ab(ii,iii,iv,v)
Assessment Date
2018/06/27
Assessor(s)
L. von Staden
Justification
Cynanchum zeyheri is a widespread species with an uncertain extent of occurrence (EOO), estimated to be between 12 579 - 21 422 km². It is however very rare, with an area of occupancy (AOO) of only 56 km². It is known from seven to 10 locations, and continues to decline across its range due to ongoing habitat loss and degradation and competition from alien invasive plants.
Distribution
Endemism
South African endemic
Provincial distribution
Western Cape
Range
This species is endemic to the Western Cape coastal lowlands, where it is known from isolated occurrences around Saldanha, the Cape Peninsula and the Agulhas Plain.
Habitat and Ecology
Major system
Terrestrial
Major habitats
Cape Flats Dune Strandveld, Langebaan Dune Strandveld, Saldanha Limestone Strandveld, Peninsula Shale Renosterveld, De Hoop Limestone Fynbos, Saldanha Flats Strandveld, Saldanha Granite Strandveld, Eastern Ruens Shale Renosterveld, Albertinia Sand Fynbos, Agulhas Sand Fynbos, Cape Flats Sand Fynbos, Overberg Dune Strandveld, Canca Limestone Fynbos
Description
It occurs on flats and lower slopes in renosterveld, strandveld and limestone fynbos.
Threats
This species has lost habitat to urban expansion on the Cape Peninsula in the past (Liede 1993), but its remaining habitat is now protected. It continues to be threatened by habitat loss to urban expansion and mining on the Vredenburg Peninsula, as well as habitat loss to crop cultivation, development and competition from alien invasive plants on the Agulhas Plain and in the Overberg.
Population

It is an extremely rare species, known from only a few collections, scattered over a wide area. Subpopulations are extremely small - two recent field observations recorded subpopulations of fewer than 10 plants, although it is said to be common on Robben Island. The population is declining on the Vredenburg Peninsula and the Agulhas Plain.


Population trend
Decreasing
Assessment History
Taxon assessed
Status and Criteria
Citation/Red List version
Cynanchum zeyheri Schltr.Least Concern Raimondo et al. (2009)
Cynanchum zeyheri Schltr.Vulnerable Hilton-Taylor (1996)
Bibliography

Goldblatt, P. and Manning, J.C. 2000. Cape Plants: A conspectus of the Cape Flora of South Africa. Strelitzia 9. National Botanical Institute, Cape Town.


Hilton-Taylor, C. 1996. Red data list of southern African plants. Strelitzia 4. South African National Botanical Institute, Pretoria.


Liede, S. 1993. A taxonomic revision of the genus Cynanchum L. (Asclepiadaceae) in southern Africa. Botanische Jahrbücher für Systematik 114:503-550.


Manning, J.C. and Goldblatt, P. 2012. Plants of the Greater Cape Floristic Region 1: The Core Cape Flora. Strelitzia 29. South African National Biodiversity Institute, Pretoria.


Raimondo, D., von Staden, L., Foden, W., Victor, J.E., Helme, N.A., Turner, R.C., Kamundi, D.A. and Manyama, P.A. 2009. Red List of South African Plants. Strelitzia 25. South African National Biodiversity Institute, Pretoria.


Citation
von Staden, L. 2018. Cynanchum zeyheri Schltr. National Assessment: Red List of South African Plants version 2020.1. Accessed on 2020/07/10

Comment on this assessment Comment on this assessment
Distribution map

© C. Merry

© C. Merry

© C. Merry


Search for images of Cynanchum zeyheri on iNaturalist