Systematics of Clematis in Nepal, the evolution of tribe Anemoneae DC. (Ranunculaceae) and phylogeography and the dynamics of speciation in the Himalaya
The genus Clematis L. (Ranunculaceae) was used as a new model group to assess the role of
the Himalayan orogeny on generation of biodiversity through investigations of its
phylogeny, phylogeography and taxonomy.
Although existing checklists include 28 species of Clematis from Nepal, a comprehensive
taxonomic revision of available material in herbaria and additional sampling from fieldwork
during this study has led to the recognition of 21 species of Clematis in Nepal, including one
species (C. kilungensis) not previously recorded from Nepal.
Exisiting phylogenetic and taxonomic concepts were tested with the addition of new samples
from Nepal. The results highlight the shortcomings of the previous studies which were
poorly resolved and indicate the need for a thorough revision of the sectional classification.
Despite the increased sampling the results are still equivocal due to poor statistical support
along the backbone of the phylogeny. Groups of species in well supported terminal clades
are broadly comparable with results from previous studies although there are fewer clearly
recognisable and well supported clades.
The published dates for the evolution of Clematis were tested and the methodology of the
previous study critically reappraised. The results indicate that the genus Clematis is
approximately twice as old as previously reported and evolved in the middle Miocene. The
phylogeny also demonstrates that, even allowing for poor support for the relationships
between groups of species within Clematis, the extant Nepalese species must have multiple
independent origins from at least 6 different colonisations. With their occurrence in the
Pliocene and Pleistocene, these events are relatively recent in relation to the Himalayan
orogeny, and may be linked more to the dispersal ability of Clematis than to the direct effects
of the orogeny.
Additional Nepalese samples of Koenigia and Meconopsis were added to exisiting datasets
and these were reanalysed. The result from Clematis, Koenigia and Meconopsis were
appraised in light of the the geocientific literature and previously published phylogeographic
studies to create an overview of the drivers behind speciation in the Himalaya