Predicting alpha diversity of African rain forests: models based on climate and satellite-derived data do not perform better than a purely spatial model

Ingrid Parmentier, Ryan J. Harrigan, Wolfgang Buermann, Edward T. A. Mitchard, Sassan Saatchi, Yadvinder Malhi, Frans Bongers, William D. Hawthorne, Miguel E. Leal, Simon L. Lewis, Louis Nusbaumer, Douglas Sheil, Marc S. M. Sosef, Kofi Affum-Baffoe, Adama Bakayoko, George B. Chuyong, Cyrille Chatelain, James A. Comiskey, Gilles Dauby, Jean-Louis DoucetSophie Fauset, Laurent Gautier, Jean-Francois Gillet, David Kenfack, Francois N. Kouame, Edouard K. Kouassi, Lazare A. Kouka, Marc P. E. Parren, Kelvin S-H Peh, Jan M. Reitsma, Bruno Senterre, Bonaventure Sonke, Terry C. H. Sunderland, Mike D. Swaine, Mbatchou G. P. Tchouto, Duncan Thomas, Johan L. C. H. Van Valkenburg, Olivier J. Hardy

Research output: Contribution to journalArticlepeer-review


Aim Our aim was to evaluate the extent to which we can predict and map tree alpha diversity across broad spatial scales either by using climate and remote sensing data or by exploiting spatial autocorrelation patterns.

Location Tropical rain forest, West Africa and Atlantic Central Africa.

Methods Alpha diversity estimates were compiled for trees with diameter at breast height >= 10 cm in 573 inventory plots. Linear regression (ordinary least squares, OLS) and random forest (RF) statistical techniques were used to project alpha diversity estimates at unsampled locations using climate data and remote sensing data [Moderate Resolution Imaging Spectroradiometer (MODIS), normalized difference vegetation index (NDVI), Quick Scatterometer (QSCAT), tree cover, elevation]. The prediction reliabilities of OLS and RF models were evaluated using a novel approach and compared to that of a kriging model based on geographic location alone.

Results The predictive power of the kriging model was comparable to that of OLS and RF models based on climatic and remote sensing data. The three models provided congruent predictions of alpha diversity in well-sampled areas but not in poorly inventoried locations. The reliability of the predictions of all three models declined markedly with distance from points with inventory data, becoming very low at distances > 50 km. According to inventory data, Atlantic Central African forests display a higher mean alpha diversity than do West African forests.

Main conclusions The lower tree alpha diversity in West Africa than in Atlantic Central Africa may reflect a richer regional species pool in the latter. Our results emphasize and illustrate the need to test model predictions in a spatially explicit manner. Good OLS or RF model predictions from inventory data at short distance largely result from the strong spatial autocorrelation displayed by both the alpha diversity and the predictive variables rather than necessarily from causal relationships. Our results suggest that alpha diversity is driven by history rather than by the contemporary environment. Given the low predictive power of models, we call for a major effort to broaden the geographical extent and intensity of forest assessments to expand our knowledge of African rain forest diversity.

Original languageEnglish
Pages (from-to)1164-1176
Number of pages13
JournalJournal of biogeography
Issue number6
Early online date7 Feb 2011
Publication statusPublished - 1 Jun 2011


Dive into the research topics of 'Predicting alpha diversity of African rain forests: models based on climate and satellite-derived data do not perform better than a purely spatial model'. Together they form a unique fingerprint.

Cite this