Taxonomy
Scientific Name
Wolffiella denticulata (Hegelm.) Hegelm.
Higher Classification
Monocotyledons
Family
LEMNACEAE
National Status
Status and Criteria
Vulnerable D2
Assessment Date
2007/09/17
Assessor(s)
C.R. Scott-Shaw & L. von Staden
Justification
Known from four locations. Potentially threatened by habitat degradation due to water extraction, pollution and urban development.
Distribution
Endemism
Not endemic to South Africa
Provincial distribution
KwaZulu-Natal
Range
Northern KwaZulu-Natal between Mtunzini and Kosi Bay and in Mozambique.
Habitat and Ecology
Major system
Freshwater
Major habitats
Swamp Forest
Description
Floating in coastal freshwater marshes, lakes or slow moving streams.
Threats
There are many impacts on the habitat of this species outside the Greater St. Lucia Wetland Park, which mostly results in decreasing water quality. Around Mtunzini and Richards Bay river systems near the coast are undoubtedly degraded and impacted by pollution and eutrophication. However, some species of the Lemnaceae are quite tolerant of eutrophication and are used as indicators of eutrophied systems, but not enough is known about the ecology of Wolffiella denticulata to say whether it is tolerant of pollution or not. Fairly recent collections from the Richards Bay area could indicate that this species is able to persist despite degradation of water quality. Water extraction for agricultural and household purposes from the Mkuze and Mbazwane River systems around Mbazwane (Sodwana Bay), where most collections of this species come from, could possibly impact on the habitat by reducing water levels (C.R. Scott-Shaw pers. comm.). Industrial and urban development around Richards Bay could result in a loss of habitat if the Nseleni River system were to be channelled (as has happened to most of the streams in the harbour area) but legislation against wetland destruction could prevent this. However, in spite of legislation developments do not always proceed sensitively and this remains a serious potential threat.
Population
Population trend
Stable
Conservation
The habitat of this species in South Africa is mostly well protected within the Greater St. Lucia Wetland Park.
Assessment History
Taxon assessed
Status and Criteria
Citation/Red List version
Wolffiella denticulata (Hegelm.) Hegelm.VU D2Raimondo et al. (2009)
Wolffiella denticulata (Hegelm.) Hegelm.VU Scott-Shaw (1999)
Bibliography

Cook, C.D.K. 2004. Aquatic and wetland plants of southern Africa. Backhuys Publishers, Leiden, The Netherlands.


Obermeyer-Mauve, A.A. 1966. A note on two rarely seen minute flowering plants, Wolffiella denticulata and W. welwitschii (Lemnaceae). South African Journal of Science 62:277-278.


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.


Scott-Shaw, C.R. 1999. Rare and threatened plants of KwaZulu-Natal and neighbouring regions. KwaZulu-Natal Nature Conservation Service, Pietermaritzburg.


Sieben, E.J.J. 2009. The status and distribution of vascular plants (Magnoliophyta, Lycophyta, Pteridophyta). In: W.R.T. Darwall, K.G. Smith, D. Tweddle and P. Skelton (eds.), The status and distribution of freshwater biodiversity in southern Africa (pp. 83-98), IUCN and SAIAB, Gland, Switzerland and Grahamstown, South Africa.


Citation
Scott-Shaw, C.R. & von Staden, L. 2007. Wolffiella denticulata (Hegelm.) Hegelm. National Assessment: Red List of South African Plants version 2020.1. Accessed on 2024/02/29

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Distribution map


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