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The status of Protea caffra subsp. caffra and Harmonia axyridis in the habitat of the Critically Endangered Pennington’s Protea butterfly Capys penningtoni


Nozipho Kheswa
Sethabile Mbatha
Adrian J. Armstrong
Sharon L. Louw

Abstract

Aerial photography provides historic record of features at the time the photograph was captured, and can assist with exploring changes in the habitat of threatened species. The host-plant of the Critically Endangered, endemic Pennington’s Protea butterfly Capys penningtoni, the Common Sugarbush Protea caffra Meisn. subsp. caffra, is a resprouter after fire which eventually dies if burnt too frequently. Six sites (Marwaqa Nature Reserve, Impendle Nature Reserve, Clairmont Mountain Nature Reserve, Lotheni Nature Reserve, Lot 93 1821 near Mkhomazi River [Nxamalala Traditional Council] and Mt Le Sueur) where the butterfly species had been previously recorded were selected to estimate the number of adult P. caffra subsp. caffra trees present using aerial photographs (2009). Protea trees in the vicinity of the C. penningtoni butterfly collection sites were point-digitised off aerial photographs. Polygons were digitised around coverages of protea trees using a distance of 50 m between trees to determine the outer margin of each coverage. The imagery data were ground-truthed by verifying the location and identities of P. caffra subsp. caffra trees at each site, using a sample of the total number of digitised trees. The ground-truthing enabled the separation of P. caffra subsp. caffra trees from Silver Protea Protea roupelliae trees, and the separation of P. caffra subsp. caffra trees with overlapping canopies. Contemporary presence of P. caffra subsp. caffra trees in relation to presence in 2009 was determined. Fire frequency data for each site was obtained via landsatlook viewer (USGS). We found that the protea savanna at most of the sampled sites was burnt about once every year between July and September. This project indicated the potential utility of aerial photographs and aerial imagery for the purposes of assessing the status of P. caffra subsp. caffra and H. axyridis in the habitat of the Critically Endangered and endemic C. penningtoni and for directing the placement of sampling plots in the field.


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eISSN: 2307-5031