The vegetation of three localities of the threatened butterfly species Chrysoritis aureus (Lepidoptera: Lycaenidae)

Abstract

The vegetation and habitat characteristics of three localities of Chrysoritis aureus at theAlice Glockner Nature Reserve, Suikerbosrand Nature Reserve and Malanskraal farmnear Heidelberg in South Africa, were compared. A numerical classification technique,TWINSPAN, was used and refined by using Braun Blanquet procedures to classify thevegetation at the different localities. A DCA ordination was applied to confirm theresults of the classification. Although the general vegetation structure at the three habitats of Chrysoritis aureus were found to be similar, marked differences in the floristiccomposition were evidenced. A different sub-community, compared to the vegetation atSuikerbosrand and Alice Glockner Nature Reserve, was recorded at the Malanskraalhabitat of Chrysoritis aureus. These differences in floristic composition, but with similarities in vegetation structure, indicate the possible importance of fire for the ultimatesurvival of these butterflies in the Rocky Highveld Grassland. The host plant ofChrysoritis aureus, Clutia pulchella, collected at Malanskraal differed markedly andconsistently in their morphology, compared to the individuals from the habitats atSuikerbosrand and Alice Glockner Nature Reserve. These differences in the floristiccomposition of one of the habitats compared to the others, raise research questions concerning the butterfly metapopulation structure, since the subpopulations seem to beadapted to slightly different habitat conditions. The variation in the habitat suggests thatthe “last remaining locality scenario” for other localised butterflies in South Africa, suchas  Orachrysops niobe, needs to be redressed. Management strategies are addressedwhile the importance of conserving rare, localised ecosystems are highlighted by thephytosociological study