Sandstone Quince

Taxonomy
Scientific Name
Dahlgrenodendron natalense (J.H.Ross) J.J.M.van der Merwe & A.E.van Wyk
Higher Classification
Dicotyledons
Family
LAURACEAE
Synonyms
Beilschmiedia natalensis J.H.Ross
Common Names
Natal Quince (e), Natal-kweper (a), River Laurel (e), Sandsteen-kweper (a), Sandstone Quince (e)
National Status
Status and Criteria
Endangered C2a(i)
Assessment Date
2007/11/27
Assessor(s)
L. von Staden & A.T.D. Abbott
Justification
A rare tree occurring in isolated forest fragments in KwaZulu-Natal, but more abundant in Pondoland forests. Subpopulations in the northern parts of the range are small and not viable, some consisting of a single individual. These are declining as a result of failed reproduction. Even in healthier subpopulations in the Pondoland region, reproduction occurs mainly through coppicing and seedlings are extremely rare. Pondoland subpopulations contain up to 40-50 mature individuals, and the total population is estimated to be fewer than 1000 mature individuals.
Distribution
Endemism
South African endemic
Provincial distribution
Eastern Cape, KwaZulu-Natal
Range
Pondoland, from Mkambati to Umtamvuna, with isolated occurrences at Umdoni Park, Pinetown and Ozwatini. Possibly extinct at Ngoye.
Habitat and Ecology
Major system
Terrestrial
Major habitats
Northern Coastal Forest, Scarp Forest
Description
Scarp forest, most typically on Natal group and Msikaba Formation sandstones, but also on granite. Usually near streams.
Threats
Forests at three sites where this species occurs are disappearing at an alarming rate due to invasive alien encroachment and forest destruction for subsistence farming (Scott-Shaw 1999). One subpopulation within the Mkambati Nature Reserve is threatened by invasive Chromolaena odorata (K. van der Walt pers. obs.).
Population

Only mature individuals are present in the wild (Abbott 2005). Small subpopulations (two consisting of single trees) in the northern section of the range are dying out as a result of failed recruitment, which is probably impaired by a system of synchronous dichogamy, by which outcrossing is enforced, and which is known to operate in some members of the Lauraceae (Van der Merwe et al. 1988). Fruit set is generally very low (Abbott 2005), and the scarcity of this species may be as a result of the difficulty to achieve optimal fruit set (Van der Merwe et al 1988). Even in some of the healthier subpopulations of the Pondoland region, juveniles present all appear to be the result of coppicing around the base of older individuals (K. van der Walt, pers. obs. 2007). According to Scott-Shaw (1999) there are only eight known subpopulations. However, at least one more has been found since then in the Mkambati Nature Reserve, and there may be a few others in inaccessible forested gorges elsewhere in Pondoland. Subpopulations are isolated from each other by being restricted to individual river valleys. Van der Merwe et al (1988) estimated that there are about 200 mature individuals. However, a few more subpopulations have been located since then and there may be still a few undiscovered ones in inaccessible forested gorges elsewhere in Pondoland. Subpopulations are always small, never larger than 40-50 mature individuals (Scott-Shaw 1999, K. van der Walt pers. obs.).


Population trend
Decreasing
Conservation
Protected in the Umtamvuna and Mkambati Nature Reserves. The habitat at Ngoye is protected in the Ngoye Forest Reserve, but this species probably no longer occurs there.
Notes
D. natalense is one of a high number of woody species endemic to, or concentrated in the relatively small southern KwaZulu-Natal-Pondoland sandstone region. Some of these taxa are thought to be relict elements of the Cretaceous/Tertiary forest flora which were present in this part of Gondwana. The Pondoland sandstone region also contains many taxonomically unique species, including one monotypic endemic family (Rhynchocalycaceae) and six monotypic genera, including Dahlgrenodendron. These taxonomically isolated species show the features of relict palaeoendemics on the brink of natural extinction. Dahlgrenodendron is regarded as a surviving representative of the ancestral stock from which the Lauraceae genera Cryptocarya and Ravensara have evolved (Van der Merwe et al 1988).
Assessment History
Taxon assessed
Status and Criteria
Citation/Red List version
Dahlgrenodendron natalense (J.H.Ross) J.J.M.van der Merwe & A.E.van WykEN C2a(i)Raimondo et al. (2009)
Dahlgrenodendron natalense (J.H.Ross) J.J.M.van der Merwe & A.E.van WykEN Scott-Shaw (1999)
Dahlgrenodendron natalense (J.H.Ross) J.J.M.van der Merwe & A.E.van WykEndangered Hilton-Taylor (1996)
Beilschmiedia natalensis J.H.RossUncertain Hall et al. (1980)
Bibliography

Boon, R. 2010. Pooley's Trees of eastern South Africa. Flora and Fauna Publications Trust, Durban.


Hall, A.V., De Winter, M., De Winter, B. and Van Oosterhout, S.A.M. 1980. Threatened plants of southern Africa. South African National Scienctific Programmes Report 45. CSIR, Pretoria.


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


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


Citation
von Staden, L. & Abbott, A.T.D. 2007. Dahlgrenodendron natalense (J.H.Ross) J.J.M.van der Merwe & A.E.van Wyk. National Assessment: Red List of South African Plants version 2020.1. Accessed on 2024/02/24

Comment on this assessment Comment on this assessment
Distribution map

© A.T.D. Abbott

© G. Nichols

© G. Nichols

© G. Nichols


Search for images of Dahlgrenodendron natalense on iNaturalist