Ginkgo enigma

There are many enigmatic plants out there in addition to the boab. One is the ginkgo (Ginkgo biloba).  It is such a different tree, biologically unique, really deserving of the moniker living fossil.  Millions of years ago it grew all across the world, and today people are familiar with it as a common street and park tree in virtually all temperate climates zones, yet its presence in “the wild” is limited to a few mountains in China – and the wildness of these populations is disputed.   It went extinct nearly everywhere, only to be brought back to life – and proliferated – due to its association with people who cultivated it and celebrated it.   Continue reading

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Our paper on how baobabs came from Africa to India just published in RSOS

Our paper on the history of introduction of the baobab, Adansonia digitata, from Africa to the Indian subcontinent and beyond, was published yesterday, 9th September, in the September issue of Royal Society Open Science. It is the first systematic biogeographic study ever done on the African baobab’s distribution outside the African continent, and in particular, in the Indian subcontinent and Indian Ocean region combining genetic analysis and historical information on trade and other social networks.

It is Open Access, so please download it from the RSOS website!

http://rsos.royalsocietypublishing.org/content/2/9/150370

Another paper that combines the results of the genetic and historical analysis with the cultural traces associated with the  African diaspora in India was published earlier this year in Environment and History, Vol 21 (1).

If you want a copy of this paper, get in touch with Priya or Karen, and we’ll send it to you!

People and the dispersal of baobabs around the Indian Ocean

[reposted from christiankull.net]

The baobab, that iconic, majestic, and grotesquely massive roots-in-the-sky tree, teaches us something surprising about “nature”.  It demonstrates that what appears to be “natural” has been – for millennia and millennia – also fundamentally “social”, for people have been important dispersal agents of these trees.  Researchers like Chris Duvall and Jean-Michel Leong Pock Tsy have shown this for the African baobabs.[1,2]  Our recently completed research project, led by Priya Rangan, demonstrates this in multiple ways around the Indian Ocean.  Baobabs are such useful and remarkable trees [3], it is hardly difficult to imagine people not picking up the hard but pleasantly light and fuzzy fruit pods and walking with them.

A young baobab near an Aboriginal rock art site

A young baobab near an Aboriginal rock art site (photo: CKull)

One part of our project looked at the single species of baobabs found in Australia: Adansonia gregorii, called boab. It grows in the Kimberley region in the northwestern part of the continent.  In a study just published in PLoS ONE [4], we combine evidence from baobab genetics [5] and Australian Aboriginal languages to show that humans have been the primary agents of baobab dispersal.  In particular, we reveal their crucial role in dispersing baobabs inland from now-submerged areas of northwest Australia during the dramatic sea-level rises at the end of the last glaciation.  (See also Priya’s blog about the study)

A further question is how the baobabs arrived in Australia in the first place.  Oceanic dispersal via seed pods floating in currents, several million years ago, remains the most plausible explanation, as our collaborator David Baum has shown [6].  Yet, another one of our baobab collaborators (and veritable Renaissance man) Jack Pettigrew advances an interesting speculative argument about a possible human role in transporting the baobabs, building on evidence from rock art in the Kimberley Continue reading

Boabs and the mystery of ancient human settlement in northwest Australia

Display at the Derby boab tree in the Kimberley (Photo: H. Rangan)

The Derby Boab Tree (Photo: H.Rangan)

In our paper just published in PLOS ONE, we show that humans were the main agents for dispersing the boab (Adansonia gregorii) in the Kimberley region of northwest Australia. We combined evidence from boab genetics and linguistic word-forms for boabs in the Aboriginal languages of the Kimberley with palaeoclimatic and archaeological studies, to reveal that these ancient settlers in the remote northwest were responsible for bringing the boabs inland as sea levels started rising dramatically 20,000 years ago.

The results of our study reveal the mystery of ancient Aboriginal settlement and interaction in the Kimberley.  Aboriginal peoples probably lived along the northwest coastal areas of the exposed continental shelf during the last Ice Age and retreated inland as these areas were flooded by rising sea levels. They carried boab fruit with them as they moved inland into central and eastern parts of the Kimberley region, and introduced the tree and associated words to other Aboriginal communities living there. Continue reading