Sickle-leaf Conebush

Taxonomy
Scientific Name
Leucadendron xanthoconus (Kuntze) K.Schum.
Higher Classification
Dicotyledons
Family
PROTEACEAE
Synonyms
Leucadendron salignum R.Br. (in part)
Common Names
Sickle-leaf Conebush (e)
National Status
Status and Criteria
Least Concern
Assessment Date
2019/06/20
Assessor(s)
A.G. Rebelo, H. Mtshali & L. von Staden
Justification
Leucadendron xanthoconus has a restricted range, but is extremely abundant within its habitat. It has declined due to habitat loss in the past, but is unlikely to experience any further significant habitat loss, as most of its remaining habitat is now protected. Spreading alien invasive plants remain a concern, and it is potentially vulnerable to climate change. Ongoing monitoring is needed to detect changes in the population trend. At present this species is not yet in danger of extinction.
Distribution
Endemism
South African endemic
Provincial distribution
Western Cape
Range
Leucadendron xanthoconus is endemic to a small area in the Western Cape, where it occurs on coastal mountains from the Cape Peninsula to Potberg on the eastern edge of the Agulhas Plain.
Habitat and Ecology
Major system
Terrestrial
Major habitats
Peninsula Sandstone Fynbos, Potberg Sandstone Fynbos, Overberg Sandstone Fynbos, Kogelberg Sandstone Fynbos, Elgin Shale Fynbos, Cape Winelands Shale Fynbos, Peninsula Shale Fynbos, Peninsula Granite Fynbos, Boland Granite Fynbos, Potberg Ferricrete Fynbos, Elim Ferricrete Fynbos, Albertinia Sand Fynbos, Agulhas Sand Fynbos, Hangklip Sand Fynbos, Western Coastal Shale Band Vegetation
Description
It occurs on lower slopes in sandstone fynbos, 0-1000 m. Mature individuals are killed by fires, and only seeds survive. Wind-dispersed seeds are stored in fire-resistant inflorescences, and released after fires. It is dioecious, with insect-pollinated male and female flowers occurring on separate plants.
Threats
This species has already lost 30% of its habitat, predominantly due to urban expansion around Cape Town, and coastal development between Gordon's Bay and Struisbaai. This loss is largely historical, with very low levels of ongoing loss recorded in recent years (2% loss between 1990 and 2014). This is because the majority of its remaining habitat is in protected areas, and therefore it is highly unlikely that population reduction will ever exceed even 10% in three generations. A combination of climate change and habitat loss models predicted that this species could decline by between 30 and 50% by 2025 (Bomhard et al. 2005), but this was based on unrealistic projections of habitat loss, and no major population reductions due to drought and increasing temperatures have yet been observed. It is threatened by competition from alien invasive plants, particularly escaped pine seedlings and Australian wattle species on the Caledon Swartberg and in the Bredasdorp Mountains. There were extensive efforts to clear alien invasive plants on the Cape Peninsula in the early 2000s, and most of its habitat within protected areas has returned to good condition, although ongoing alien invasive control is needed due to persistent soil-stored seedbanks. In the De Hoop Nature Reserve, recurring invasions by wattles remains a problem within this species' habitat on the Potberg.
Population

This species is abundant within its habitat. Subpopulations are dense, dominant and extensive, with at least 12 consisting of more than 10 000 mature individuals, and the largest subpopulation in the Bredasdorp Mountains consisting of more than 40 000 individuals. It has declined due to habitat loss in the past, but population reduction is only about 10% in three generations, as this species is a relatively short-lived reseeder. Slow, sporadic decline is likely to continue, particularly if spreading alien invasive plants within its habitat are not controlled.


Population trend
Stable
Assessment History
Taxon assessed
Status and Criteria
Citation/Red List version
Leucadendron xanthoconus (Kuntze) K.Schum.Least Concern Raimondo et al. (2009)
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.


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.


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.


Citation
Rebelo, A.G., Mtshali, H. & von Staden, L. 2019. Leucadendron xanthoconus (Kuntze) K.Schum. National Assessment: Red List of South African Plants version 2020.1. Accessed on 2021/09/23

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Distribution map


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