Polhillia ignota

Taxonomy
Scientific Name
Polhillia ignota Boatwr.
Higher Classification
Dicotyledons
Family
FABACEAE
National Status
Status and Criteria
Critically Endangered B1ab(iii)+2ab(iii); C2a(i,ii); D
Assessment Date
2016/10/06
Assessor(s)
I. Ebrahim, N.A. Helme, D. Raimondo & D. van der Colff
Justification
A single, small subpopulation of 13 plants remain in a renosterveld fragment near Eendekuil (EOO 4 km², AOO <4 km²). The population is expected to continue to decline due to ongoing threats of habitat degradation and competition from alien invasive plants.
Distribution
Endemism
South African endemic
Provincial distribution
Western Cape
Range
Northern Swartland between Vredenburg, Eendekuil and Porterville.
Habitat and Ecology
Major system
Terrestrial
Major habitats
Swartland Shale Renosterveld
Description
Shale renosterveld.
Threats
Polhillia ignota occurs in Critically Endangered Swartland Shale Renosterveld, of which <10% remains, after extensive loss to agricultural expansion. The only known subpopulation occurs in a small fragment of renosterveld among crop fields. It is potentially threatened by habitat degradation due to overgrazing - small remnants of renosterveld are often overstocked with livestock, but grazing pressure on the site is currently low. This fragment is unlikely to be lost to crop cultivation, as it is too steep and rocky to plough. Alien invasive plants are present in the habitat, and may become a threat to the population in future if it is not cleared.
Population

Polhillia ignota was described in 2010 based on two herbarium collections dating from 1904 and 1928 (Boatwright 2010). Both did not have precise locality details, but came from an area that has been extensively modified for crop cultivation, and the species was presumed extinct, as searches in the general area between 2005 and 2014 failed to locate any surviving populations. In 2016, volunteers of the Custodians of Rare and Endangered Wildflowers (CREW) Programme came across a small subpopulation much further north from the area it was previously recorded, suggesting that it may have had a much wider distribution in the past. It is a large, conspicuous shrub, and therefore unlikely to be overlooked. With less than 10% of its habitat remaining intact, it is very unlikely that many other subpopulations still exist, and the subpopulation discovered in 2016 is quite possibly the last remaining. It consists of 13 mature individuals. The population trend is not known, but it is expected to continue to decline due to the ongoing threat of habitat loss and degradation.


Population trend
Decreasing
Assessment History
Taxon assessed
Status and Criteria
Citation/Red List version
Polhillia ignota Boatwr.Extinct 2014.1
Bibliography

Boatwright, J.S. 2010. A rare new species of Polhillia (Genisteae, Fabaceae). South African Journal of Botany 76(1):142-145.


Department of Environmental Affairs. 2011. National Environmental Management: Biodiversity Act, 2004: National list of ecosystems that are threatened and in need of protection. Government Notice 1002. Government Gazette No 34809, 9 December 2011.


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.


Citation
Ebrahim, I., Helme, N.A., Raimondo, D. & van der Colff, D. 2016. Polhillia ignota Boatwr. National Assessment: Red List of South African Plants version 2017.1. Accessed on 2017/06/25

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Distribution map

© B. du Preez

© B. du Preez

© B. du Preez

© B. du Preez

© I. Ebrahim

© I. Ebrahim


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