The distribution of cultural and biological diversity in Africa

Anthropologists, biologists and linguists have all noted an apparent coincidence in species diversity and human cultural or linguistic diversity. We present, to our knowledge, one of the first quantitative descriptions of this coincidence and show that, for 2° × 2° grid cells across sub–Saharan Africa, cultural diversity and vertebrate species diversity exhibit marked similarities in their overall distribution. In addition, we show that 71% of the observed variation in species richness and 36% in language richness can be explained on the basis of environmental factors, suggesting that similar factors, especially those associated with rainfall and productivity, affect the distributions of both species and languages. Nevertheless, the form of the relationships between species richness and language richness and environmental factors differs, and it is unlikely that comparable mechanisms underpin the similar patterns of species and language richness. Moreover, the fact that the environmental factors considered here explain less than half of the variation in language richness indicates that other factors, many of which are likely to be historical or social, also influence the distribution of languages.

[1]  J. Lovett,et al.  Geographical patterns of old and young species in African forest biota: the significance of specific montane areas as evolutionary centres , 1997, Biodiversity & Conservation.

[2]  D. Jablonski.  The tropics as a source of evolutionary novelty through geological time , 1993, Nature.

[3]  D. Ehrlich,et al.  Are biodiversity ‘hotspots’ correlated with current ecoclimatic stability? A pilot study using the NOAA-AVHRR remote sensing data , 1997, Biodiversity & Conservation.

[4]  F. White.  The vegetation of Africa : a descriptive memoir to accompany the Unesco/AETFAT/UNSO vegetation map of Africa , 1985 .

[5]  Daniel Nettle,et al.  Explaining Global Patterns of Language Diversity , 1998 .

[6]  Johanna Nichols,et al.  AND THE FIRST SETTLEMENT OF THE NEW WORLD , 1990 .

[7]  Johanna Nichols,et al.  Modeling Ancient Population Structures and Movement in Linguistics , 1997 .

[8]  M. Pagel,et al.  A latitudinal gradient in the density of human languages in North America , 1995, Proceedings of the Royal Society of London. Series B: Biological Sciences.

[9]  G. Graves,et al.  Multiscale assessment of patterns of avian species richness , 2001, Proceedings of the National Academy of Sciences of the United States of America.

[10]  L. Maffi,et al.  Indigenous and Traditional Peoples of the World and Ecoregion Conservation: An Integrated Approach to Conserving the World’s Biological and Cultural Diversity , 2000 .

[11]  Mark V. Lomolino,et al.  Species Diversity in Space and Time. , 1996 .

[12]  Daniel Nettle,et al.  Language Diversity in West Africa: An Ecological Approach , 1996 .

[13]  Martin Jenkins,et al.  Global biodiversity: earth's living resources in the 21st century. , 2000 .

[14]  Colwell,et al.  The mid-domain effect: geometric constraints on the geography of species richness. , 2000, Trends in ecology & evolution.

[15]  D. Olson,et al.  The Global 200: A Representation Approach to Conserving the Earth’s Most Biologically Valuable Ecoregions , 1998 .

[16]  C. Rahbek,et al.  Conservation conflicts across Africa. , 2001, Science.

[17]  E. Pianka.  Latitudinal gradients in species diversity , 1989 .

[18]  Thomas M. Smith,et al.  A global land primary productivity and phytogeography model , 1995 .

[19]  J. Nichols.  Linguistic Diversity in Space and Time , 1992 .

[20]  P. Clifford,et al.  Modifying the t test for assessing the correlation between two spatial processes , 1993 .

[21]  Barbara F. Grimes.  Ethnologue Languages of the World , 1988 .

[22]  S. Lidgard,et al.  Angiosperm Diversification and Paleolatitudinal Gradients in Cretaceous Floristic Diversity , 1989, Science.

[23]  E. Pianka.  Latitudinal Gradients in Species Diversity: A Review of Concepts , 1966, The American Naturalist.

[24]  K. Rohde.  Latitudinal gradients in species diversity and Rapoport's rule revisited: a review of recent work and what can parasites teach us about the causes of the gradients? , 1999 .

[25]  Jared M. Diamond,et al.  Guns, germs and steel : how the inequalities of wealth and power among modern peoples were moulded by prehistory , 1997 .

[26]  Oliver Rackham,et al.  The History Of The Countryside , 1986 .

[27]  D. Currie.  Energy and Large-Scale Patterns of Animal- and Plant-Species Richness , 1991, The American Naturalist.

[28]  P. Williams,et al.  Toward a Blueprint for Conservation in Africa , 2001 .

[29]  J. Iliffe.  Africans: The History of a Continent , 1995 .

[30]  A. Magurran.  Ecological Diversity and Its Measurement , 1988, Springer Netherlands.

[31]  F. G. Stehli,et al.  Generation and Maintenance of Gradients in Taxonomic Diversity , 1969, Science.

[32]  C. Rahbek,et al.  Geometric constraints explain much of the species richness pattern in African birds , 2001, Proceedings of the National Academy of Sciences of the United States of America.

[33]  Alfred W. Crosby,et al.  Ecological Imperialism: The Biological Expansion of Europe, 900-1900 , 1988 .

[34]  P. Jones,et al.  Representing Twentieth-Century Space-Time Climate Variability. Part II: Development of 1901-96 Monthly Grids of Terrestrial Surface Climate , 2000 .

[35]  M. Pagel.  The Evolutionary Emergence of Language: The History, Rate and Pattern of World Linguistic Evolution , 2000 .