Taxonomy
Scientific Name
Diascia caitliniae K.E.Steiner
Higher Classification
Dicotyledons
Family
SCROPHULARIACEAE
National Status
Status and Criteria
Endangered B1ab(i,ii,iii,iv,v)+2ab(i,ii,iii,iv,v)
Assessment Date
2012/02/03
Assessor(s)
L. von Staden & C. von Witt
Justification
A rare and highly localized endemic (EOO <8 km²), currently known from two small subpopulations, one threatened by a proposed mine. Other threats include habitat loss to crop cultivation, habitat fragmentation and too irregular fires.
Distribution
Endemism
South African endemic
Provincial distribution
Western Cape
Range
Krom Antonies River Valley, northern Piketberg.
Habitat and Ecology
Major system
Terrestrial
Major habitats
Swartland Shale Renosterveld, Piketberg Sandstone Fynbos
Description
Sandy loam to clay soils on lower southwest-facing slopes and flats at the interface between sandstone fynbos and shale renosterveld.
Threats
The largest known subpopulation is likely to be severely affected by a proposed tungsten mine in the valley. A second smaller subpopulation is not currently threatened, but is potentially threatened by expansion of nearby crop fields. The Krom Antonies River Valley is already extensively transformed to crop cultivation, and within the valley, only small fragments of natural vegetation remain that are infrequently burnt. Subpopulations on fragments are likely to be threatened by a lack of fire, as this short-lived species is stimulated by fire to grow and flower, remaining dormant within the soil seed bank for most of the fire interval.
Population

Only two subpopulations are currently known, both were observed within the first year after fire on two adjacent farms. The largest subpopulation consists of between 200 and 300 mature individuals, and is likely to be severely affected if a proposed tungsten mine in the valley is approved. The second, smaller population consists of ±30 mature individuals. The species is a short-lived, fire stimulated herb, which means that it is easily overlooked and other subpopulations may exist. The species has however never been collected elsewhere in the Piketberg region, indicating that it is quite likely endemic to the Krom Antonies River Valley.


Population trend
Decreasing
Assessment History
Taxon assessed
Status and Criteria
Citation/Red List version
Diascia caitliniae K.E.SteinerEN B1ab(i,ii,iii,iv,v)+2ab(i,ii,iii,iv,v)2012.1
Bibliography

Steiner, K.E. 2011. A new endemic Diascia (Scrophulariaceae) threatened by proposed tungsten mining in the Western Cape. South African Journal of Botany 77(4):777-781.


Citation
von Staden, L. & von Witt, C. 2012. Diascia caitliniae K.E.Steiner. National Assessment: Red List of South African Plants version 2020.1. Accessed on 2021/04/21

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Distribution map

© C. von Witt

© C. von Witt

© C. von Witt

© C. von Witt

© C. von Witt


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