SANBI

Rationale

This taxon has a very restricted range and is endemic to the Western Cape Province in South Africa (EOO 643 km2, AOO 16 km2). There are three locations, with severe fragmentation - the locations are separated by 80-120 km, far greater than the average dispersal distance of this taxon of 1-2 km. The taxon is under threat to the extent that it may well be extinct at its type locality at Brenton near Knysna, and cannot be found at the other locations. The loss of the Brenton subpopulation over the last 20 years has reduced the EOO and AOO and habitat quality has generally declined. It has not been seen at any of its locations for nearly 20 years, with the whole area being searched several times per year during the flight period. Even when the Brenton subpopulation existed the taxon was very scarce and the population overall was < 250 mature individuals. 95% of all records historically are from one subpopulation (Brenton). It therefore qualifies as Critically Endangered under criterion C and may be Possibly Extinct. This taxon was previously assessed as Data Deficient due to taxonomic uncertainties. However, recent improved knowledge of its distribution and population size has enabled an assessment to be carried out that assumes all the known subpopulations are the same taxon. It has not been seen at any of its locations for nearly 20 years, with the whole area being searched several times per year during the flight period and it would therefore have been Possibly Extinct for the previous assessment. Thus the change in status is non-genuine.

Distribution

Endemic to the Western Cape Province in South Africa, only recorded from the Still Bay area in the west, Brenton on Sea near Knysna and from Goesabos (Tsitsikamma) in the east.

Decline

"At Brenton on Sea all the previously known localities have become overgrown with alien vegetation such as pines (Pinus radiata), Rooikrans (Acacia cyclops), Port Jackson Willow (Acacia saligna), and Black Wattle (Acacia mearnsii).\nThe Still Bay subpopulation had a single record in 2000, but have been no records from the Goesabos subpopulation since 1980.\n"

Habitat View more ecological information

Population trend

Trend

The taxon has been recorded from Brenton on Sea, Still Bay and Goesabos near the Storms River. Over 95% of the population historically has been recorded at Brenton, with very few records from the other places.

Threats

This subspecies has already disappeared from some of its former localities. Threats to the remaining subpopulations are habitat destruction and encroachment of alien vegetation. At Brenton on Sea, which is probably the only extant subpopulation, there is severe habitat degradation due to alien vegetation invasion, resulting in shading and fragmentation of the habitat, and to housing development, with loss of connectivity of microhabitats. The invasive alien vegetation consists chiefly of Rooikrans (Acacia Cyclops), Black Wattle ((A. mearnsii) and pines ((Pinus radiata). The very small total population size and minute last known area of occupancy at Brenton on Sea (< 0.5 km2) make this subspecies exceptionally vulnerable to any changing conditions. The fire frequency at Brenton was drastically reduced, leading eventually to a massive increase in fuel load and an extremely severe fire (June 2017). It is unknown if the Brenton subpopulation has survived the fire. The status of the weak subpopulation near Still Bay is unknown, since it has not been seen there since the 1990’s. The Goesabos records are from even earlier and searches for this locality have so far not been successful.

Conservation

Searches have been conducted over the last 20 years to ascertain whether this taxon is still extant at or around Brenton on Sea, without success. A taxonomic/phylogenetic study is in progress to determine whether the subpopulation near Still Bay belongs to this taxon, but is handicapped by the lack of fresh DNA samples. An alien invasive plant eradication program and habitat restoration is required at Brenton on Sea, but is being prevented by the landowner who hopes to be awarded development rights. The authorities have been informed of the situation.

References

[@book{772,
 address = {Johannesburg &Cape Town},
 author = {Mecenero, S., Ball, J.B., Edge, D.A., Hamer, M.L., Henning, G.A., Krüger, M., Pringle, E.L., Terblanche, R.F. & Williams, M.C. (eds)},
 publisher = {Saftronics (pty) Ltd and  Animal Demography Unit, University of Cape Town},
 title = {Conservation assessment of butterflies of South Africa, Lesotho and Swaziland: Red List and Atlas.},
 year = {2013}
}
,@book{772,
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 year = {2009}
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 title = {Biological observations and taxonomic review based on morphological characters in the myrmecophilous genus <i>Chrysoritis</i> Butler (Lepidoptera: Lycaenidae: Aphnaeini). },
 volume = {18},
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,@article{168299647,
 author = {Pringle, E.L.L.},
 journal = {Metamorphosis},
 pages = {107–114, 1 pl.},
 title = {Four new Lycaenidae from the Cape Province, South Africa},
 volume = {5},
 year = {1994}
}
,]

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