Re-opening the case of Frankenflora: Evidence of hybridisation between local and introduced Protea species at Van Stadens Wildflower Reserve

Abstract

The lack of examples of hybridisation within South African Cape Fynbos lineages gives the impression that interspecific hybridisation events may be rare in this system. If this is the case, then long-distance translocations of plant species across the Cape are unlikely to have any impact on the genetic component of biodiversity. Here we demonstrate that local populations of Protea eximia have hybridised with the non-local and introduced Protea susannae at Van Stadens Wildflower Reserve using morphological and genetic data; DNA sequence data were obtained from the internal transcribed spacer from the nuclear ribosomal cistron and a noncoding region of the chloroplast. Of the 24 plants from the reserve that were analysed, 11 were identified as hybrids, and comparing nuclear and chloroplast signals indicated bidirectional gene-flow between these species. This is the first study demonstrating the potential threat of long-distance dispersal in a Cape lineage to the genetic integrity of local populations.