SORA Awardee 2008
Dr. Benny Bytebier
Project: History of the genus Habenaria
With 180 species currently recognised, Disa is one of the largest African terrestrial orchid genera. The genus is widespread throughout Africa but is surprisingly species-rich in the Cape Floristic Region, where 99 species occur. The charismatic Disa uniflora, the 'Pride of Table Mountain', is well known in horticultural circles and is often used as an emblem in the Cape. The various species can be found from the coastal sands to the summits of the highest mountains, yet they are never common. During this talk we will learn about how a genealogy of the genus can be used to trace its origin and how it spread throughout the continent. We will explore its current ecology and see if that can also tell us something about past climates and landscapes. The patterns that emerge from this may not be unique for this genus, but are most likely shared with other orchid genera. The Swiss Orchid Research Award will allow us to investigate another large orchid genus, namely Habenaria, which is much more common in the grasslands and miombo woodlands of south central and eastern Africa and see how it differs from Disa. Lastly, on the basis of an example, we will demonstrate that successful conservation can only be done if the natural history of a species is sufficiently known, something to which the general public can certainly make a meaningful contribution.
SORA Sponsors 2008
The Swiss Orchid Foundation wishes to thank the following companies for sponsoring the Swiss Orchid Research Award 2008 (in alphabetical order):
Here you can find Dr. Bytebier's lecture on African terrestrial orchids:
SORA 2008 Award Presentation
Bytebier B, Antonelli A, Bellstedt DU, Linder HP 2010: Estimating the age of fire in the Cape flora of South Africa from an orchid phylogeny. Proc. R. Soc. B online doi: 10.1098/rspb.2010.1035 abstract
Estimating the age of fire in the Cape flora of South Africa from an orchid phylogeny
Bytebier Benny, Antonelli Alexandre, Bellstedt Dirk U., Linder H. Peter
Proc. R. Soc. B online doi: 10.1098/rspb.2010.1035
Fire may have been a crucial component in the evolution of the Cape flora of South Africa, a region characterized by outstanding levels of species richness and endemism. However, there is, to date, no critical assessment of the age of the modern fire regime in this biome. Here, we exploit the presence of two obligate post-fire flowering clades in the orchid genus Disa, in conjunction with a robust, well-sampled and dated molecular phylogeny, to estimate the age by which fire must have been present. Our results indicate that summer drought (winter rainfall), the fire regime and the fynbos vegetation are several million years older than currently suggested. Summer drought and the fynbos vegetation are estimated to date back to at least the Early Miocene (ca 19.5 Ma). The current fire regime may have been established during a period of global cooling that followed the mid-Miocene Climatic Optimum (ca 15 Ma), which led to the expansion of open habitats and increased aridification. The first appearance of Disa species in the grassland biome, as well as in the subalpine habitat, is in striking agreement with reliable geological and palaeontological evidence of the age of these ecosystems, thus corroborating the efficacy of our methods. These results change our understanding of the historical mechanisms underlying botanical evolution in southern Africa, and confirm the potential of using molecular phylogenies to date events for which other information is lacking or inconclusive.
fire, Cape flora, Orchidaceae, Disa, palaeoecology
Benny Bytebier: email