| Scientific Name | Diastella proteoides (L.) Druce | Higher Classification | Dicotyledons | Family | PROTEACEAE | Synonyms | Diastella ericaefolia Salisb. ex Knight, Mimetes purpureus (L.) R.Br. | Common Names | Flats Silkypuff (e) |
National Status | Status and Criteria | Endangered A2c; C1 | Assessment Date | 2020/04/25 | Assessor(s) | A.G. Rebelo, H. Mtshali & D. Raimondo | Justification | Diastella proteoides was probably a common and widespread species historically, it is now restricted to a few remnant patches of lowland fynbos. A population reduction of 61-65% over three generations is inferred from field monitoring and habitat loss over the past 45-60 years. This species has a small population of 1392-2232 plants. Most of the subpopulations are small, consisting of fewer than 250 plants. The largest subpopulation in Riverlands has several hundred plants, but less than 1000 mature individuals. Monitoring indicates that there is continuing decline of all subpopulations. It therefore qualifies for listing as Endangered under criteria A and C. |
Distribution | Endemism | South African endemic | Provincial distribution | Western Cape | Range | Diastella proteoides occurs from Mamre and Paarl to Cape Peninsula, in the Western Cape Province, South Africa. It has an extent of occurrence (EOO) of 1431-1655 km² and an Area of Occupancy (AOO) of 236-252 km². |
Habitat and Ecology | Major system | Terrestrial | Major habitats | Swartland Granite Renosterveld, Cape Flats Sand Fynbos, Atlantis Sand Fynbos | Description | This species occurs in sandy flats, at 0-200 m. It is a short-lived species, with a generation length of 15-20 years. Mature individuals are killed by fires, and only seeds survive. Seeds are released after ripening, and dispersed by ants to their underground nests, where they are protected from predation and fire. It is pollinated by insects. |
Threats | | About 71% of the species' habitat is already irreversibly modified, and this habitat conversion has now mostly ceased. Loss of habitat was due to urban developments and agriculture mainly pasture fields and crop cultivation (cereals). Climate change and habitat loss modelling predicted that this species could decline by >80% by 2025 (Bomhard et al. 2005), but such drastic population reductions has not yet occurred.
The northern subpopulations that occur 35-50 km north of Cape Town centred on Riverlands and Pella, are heavily impacted by alien invasive acacias, and plants are regularly absent from denser infestations. The southern suburb (Rondebosch, Claremont, Wynberg and Constantia) subpopulations occur in fragments and are mostly threatened by fire exclusion. Thus plants are becoming moribund and dying. Seed banks should be intact, but will not re-establish properly without a hot summer fire.
Small stands of plants previously recorded from road verges are probably extinct due to road upgrades, and those under power lines are not viable as they are mowed regularly and no fire is permitted under powerlines.
Additional threats include increased mole-rat activity associated with disturbance, and alien invasive ants which displace native ant species. Invasive ants do not perform the function of indigenous ants, which is to bury this species' seeds in their nests where they are protected from fire. Large scale ant invasions could lead to population collapse if there is no soil-stored seed bank to regenerate from post fire. |
Population | Diastella proteoides is a range restricted species that was once common and abundant. It has significantly declined due to ongoing habitat loss and degradation. Seven subpopulations in the eastern part of the range, in Paarl, Stellenbosch, Muldersvlei, Joostenberg, Koelenhof, Eersterivier and Kraaifor, known through historical records are now locally extinct due to habitat loss.
In the southern part of the range, about two-third of range is almost totally gone, it is now found at only three places, in Tokai, Meadowridge and Kenilworth. At present all the subpopulations are small, each with less than 50 mature individuals.
The northern portion of the population is, however, still viable. The largest healthy subpopulation occurs in the Riverlands Nature Reserve, although the biggest portion of this subpopulation lies immediately to the south of the reserve under the power lines.
Recent field observations recorded 13 remaining subpopulations. All are small and occur in fragments, with the largest subpopulation from Riverlands consisting of 500-1000 plants. The population size is estimated to be between 1392 and 2232 mature individuals. The population continues to decline due to inappropriate management (fire exclusion) of the remaining fragments of suitable habitat. Based on field observations and habitat loss a population decline of 61-65% over three generations (45-60 years) is inferred, at least 20-30% of this loss has occurred over the past 2 generations (30-40 years).
| Population trend | Decreasing |
Conservation | | Five of the six remaining urban subpopulations (Tokai, Kenilworth, N1-N7 Interchange, 6 Base Ordinance Depot) have been identified as Core Conservation sites. |
Notes | | There are two forms of these species, the mat forming and bushy form. The southern subpopulations (Tokai and Meadowridge) are mat forming, like D. buekii, and appear to have longer leaves than the more bushy northern subpopulations (Forshaw 1997). This alleged difference has never been formally investigated, and was not mentioned by Rourke (1976).
There is general agreement among relevant authorities especially those involved in restoration ecology work that genetic exchange between the southern prostrate form and the northern sprawling form should be minimized. |
Assessment History |
Taxon assessed |
Status and Criteria |
Citation/Red List version | | Diastella proteoides (L.) Druce | CR A2c+3c+4c | Raimondo et al. (2009) | | Diastella proteoides (L.) Druce | Vulnerable | Hilton-Taylor (1996) | |
Bibliography | Bomhard, B., Richardson, D.M., Donaldson, J.S., Hughes, G.O., Midgley, G.F., Raimondo, D.C., Rebelo, A.G., Rouget, M. and Thuiller, W. 2005. Potential impacts of future land use and climate change on the Red List status of the Proteaceae in the Cape Floristic Region, South Africa. Global Change Biology 11(9):1452-1468.
Forshaw, A. 1997. Two races of Diastella proteoides? Protea Atlas Newsletter 35:11.
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.
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.
Rebelo, T. 2001. Sasol Proteas: A field guide to the proteas of southern Africa. (2nd ed.). Fernwood Press, Vlaeberg, Cape Town.
Rourke, J.P. 1976. A revision of Diastella (Proteaceae). Journal of South African Botany 42:185-210.
|
Citation | | Rebelo, A.G., Mtshali, H. & Raimondo, D. 2020. Diastella proteoides (L.) Druce. National Assessment: Red List of South African Plants version . Accessed on 2024/12/06 |
 Comment on this assessment
|
 © C. Merry  © C. Merry  © C. Merry  © I. Ebrahim  © I. Ebrahim
Search for images of Diastella proteoides on iNaturalist
|
