title: The evolution of traditional knowledge: environment shapes medicinal plant use in Nepal.
abstract: Traditional knowledge is influenced by ancestry, inter-cultural diffusion and interaction with the natural environment. It is problematic to assess the contributions of these influences independently because closely related ethnic groups may also be geographically close, exposed to similar environments and able to exchange knowledge readily. Medicinal plant use is one of the most important components of traditional knowledge, since plants provide healthcare for up to 80% of the world's population. Here, we assess the significance of ancestry, geographical proximity of cultures and the environment in determining medicinal plant use for 12 ethnic groups in Nepal. Incorporating phylogenetic information to account for plant evolutionary relatedness, we calculate pairwise distances that describe differences in the ethnic groups' medicinal floras and floristic environments. We also determine linguistic relatedness and geographical separation for all pairs of ethnic groups. We show that medicinal uses are most similar when cultures are found in similar floristic environments. The correlation between medicinal flora and floristic environment was positive and strongly significant, in contrast to the effects of shared ancestry and geographical proximity. These findings demonstrate the importance of adaptation to local environments, even at small spatial scale, in shaping traditional knowledge during human cultural evolution.
authors: School of Biological Sciences, University of Reading, , Reading RG6 6BX, UK, Imperial College London, , Silwood Park, Ascot, Berkshire SL5 7PY, UK, Centre for Macroevolution and Macroecology, Research School of Biology, Australian National University, , Canberra, Australian Capital Territory 0200, Australia, School of Culture, History and Language, ANU College of Asia and the Pacific, Australian National University, , Canberra, Australian Capital Territory, Australia, Royal Botanic Garden Edinburgh, , Edinburgh EH3 5LR, UK, School of Divinity, History and Philosophy, King's College, University of Aberdeen, , Aberdeen AB24 3UB, UK, Department of Plant Resources, National Herbarium and Plant Laboratories, , PO Box 3708, Godawari, Lalitpur, Nepal, Royal Botanic Gardens, Kew TW9 3DS, UK.
authors: C Haris
authors: CH
authors: Saslis-Lagoudakis
authors: Julie A
authors: JA
authors: Hawkins
authors: Simon J
authors: SJ
authors: Greenhill
authors: Colin A
authors: CA
authors: Pendry
authors: Mark F
authors: MF
authors: Watson
authors: Will
authors: W
authors: Tuladhar-Douglas
authors: Sushim R
authors: SR
authors: Baral
authors: Vincent
authors: V
authors: Savolainen
mesh_terms: D003468:Cultural Evolution; D004777:Environment; D006801:Humans; D019359:Knowledge; D008519:Medicine, Traditional; D009390:Nepal; D010946:Plants, Medicinal; D012934:Social Isolation
keywords: cultural evolution; ethnobotany; phylogeny