Taxonomy
Scientific Name
Polhillia curtisiae C.H.Stirt. & Muasya
Higher Classification
Dicotyledons
Family
FABACEAE
National Status
Status and Criteria
Critically Endangered D
Assessment Date
2014/01/20
Assessor(s)
O.E. Curtis & L. von Staden
Justification
In spite of extensive surveys, this species is known from a single location where less than 50 plants occur within a small remnant of natural vegetation surrounded by crop fields. This site was recently purchased for conservation, and through appropriate management, the population is unlikely to decline further, but continued monitoring will be necessary.
Distribution
Endemism
South African endemic
Provincial distribution
Western Cape
Range
Overberg north-east of Bredasdorp.
Habitat and Ecology
Major system
Terrestrial
Major habitats
Eastern Ruens Shale Renosterveld
Description
Dry north-facing slopes in quartz patches with deep, powdery kaolinitic soils in Eastern Rûens Shale Renosterveld.
Threats
Less than 6% of Rûens Shale Renosterveld remains after extensive loss to expanding crop cultivation (Curtis et al. 2013). It is not known what the original extent of P. curtisiae's range was, but it is likely to have declined due to habitat loss in the past. Remaining renosterveld fragments are subjected to overstocking, resulting in ongoing degradation due to overgrazing and trampling. Appropriate fire management in small fragments is also a problem. The property where the only known subpopulation of this species occurs was recently purchased for conservation (O. Curtis, pers. comm. 2013), and appropriate management for the survival of this species will be implemented.
Population

Polhillia curtisiae is known from a single quartz outcrop, in spite of intensive surveys of other similar outcrops in the area. Only 28 individuals of various ages were counted in November 2012 (Curtis et al. 2013). This species appears to be a long-lived resprouter, and post-fire recruitment is limited. It is anticipated that appropriate management of the site for conservation will halt the decline of this small population, however, ongoing monitoring will be required.


Population trend
Unknown
Assessment History
Taxon assessed
Status and Criteria
Citation/Red List version
Polhillia curtisiae C.H.Stirt. & MuasyaCR D2014.1
Bibliography

Curtis, O.E., Stirton, C.H. and Muasya, A.M. 2013. A conservation and floristic assessment of poorly known species rich quartz-silcrete outcrops within Rûens Shale Renosterveld (Overberg, Western Cape), with taxonomic descriptions of five new species. South African Journal of Botany 87:99-111.


Citation
Curtis, O.E. & von Staden, L. 2014. Polhillia curtisiae C.H.Stirt. & Muasya. National Assessment: Red List of South African Plants version 2020.1. Accessed on 2020/11/24

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Distribution map

© O.E. Curtis

© O.E. Curtis


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