Hostname: page-component-7d684dbfc8-v2qlk Total loading time: 0 Render date: 2023-09-30T16:26:47.571Z Has data issue: false Feature Flags: { "corePageComponentGetUserInfoFromSharedSession": true, "coreDisableEcommerce": false, "coreDisableSocialShare": false, "coreDisableEcommerceForArticlePurchase": false, "coreDisableEcommerceForBookPurchase": false, "coreDisableEcommerceForElementPurchase": false, "coreUseNewShare": true, "useRatesEcommerce": true } hasContentIssue false

Distribution of tree species along a gallery forest–savanna gradient: patterns, overlaps and ecological thresholds

Published online by Cambridge University Press:  02 January 2013

Akomian Fortuné Azihou*
Laboratory of Applied Ecology, Faculty of Agronomic Sciences, University of Abomey-Calavi (UAC), 01 BP 526 Cotonou, Benin
Romain Glèlè Kakaï
Laboratory of Applied Ecology, Faculty of Agronomic Sciences, University of Abomey-Calavi (UAC), 01 BP 526 Cotonou, Benin
Ronald Bellefontaine
CIRAD, UPR Génétique Forestière, F-34398 Montpellier, France
Brice Sinsin
Laboratory of Applied Ecology, Faculty of Agronomic Sciences, University of Abomey-Calavi (UAC), 01 BP 526 Cotonou, Benin
1Corresponding author. Email:


Savannas intermingled with gallery forests are dynamic habitats typical in Africa. This study aims to determine if differences in species traits lead to non-overlapping distribution of gallery-forest and savanna species and abrupt transition between gallery forest and savanna. Tree species densities were measured in 375 plots of 1500 m2 covering a total sample area of 56.25 ha along forty 3-km transects located at right angles to a riverbed with gallery forest into surrounding savanna. Location, vegetation type, soil physical properties, erosion and fire occurrence were recorded as site factors. Data analysis included the quantification of co-occurrence patterns, threshold indicator taxa analysis and fuzzy set ordination. The gallery forest–savanna gradient predicted floristic composition of plots with a correlation of 0.595 but its accuracy was locally modified by the occurrence of fire and the physical properties of soil that covered more than 30% of the range of residuals. The distribution of gallery-forest and savanna tree species did not overlap. Along the gallery forest–savanna gradient, savanna species gradually increased in density while gallery-forest species showed a community threshold at 120 m from the river beyond the width of gallery forest. The forest species driving this trend should play an important role in the dynamics of gallery forest–savanna boundaries.

Research Article
Copyright © Cambridge University Press 2013

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)



AKOEGNINOU, A., VAN DER BURG, W. J., VAN DER MAESEN, L. J. G., ADJAKIDJE, V., ESSOU, J. P., SINSIN, B. & YEDOMONHAN, H. 2006. Flore analytique du Bénin. Wageningen University Papers 06.2:11034.Google Scholar
ASH, J. 1988. The location and stability of rainforest boundaries in north-eastern Queensland, Australia. Journal of Biogeography 15:619630.CrossRefGoogle Scholar
ASKEW, G. P., MOFFATT, D. J., MONTGOMERY, R. F. & SEARL, P. L. 1970. Interrelationships of soils and vegetation in the savanna–forest boundary zone of north-eastern Mato Grosso. The Geographical Journal 136:370376.CrossRefGoogle Scholar
ASNER, G. P., ELMORE, A. J., OLANDER, L. P., MARTIN, R. E. & HARRIS, A. T. 2004. Grazing systems, ecosystem responses, and global change. Annual Review of Environment and Resources 29:261299.CrossRefGoogle Scholar
BAKER, M. E. & KING, R. S. 2010. A new method for detecting and interpreting biodiversity and ecological community thresholds. Methods in Ecology and Evolution 1:2537.CrossRefGoogle Scholar
BAKKER, J. D. 2008. Increasing the utility of indicator species analysis. Journal of Applied Ecology 45:18291835.CrossRefGoogle Scholar
BANFAI, D. S. & BOWMAN, D. 2007. Drivers of rain-forest boundary dynamics in Kakadu National Park, northern Australia: a field assessment. Journal of Tropical Ecology 23:7386.CrossRefGoogle Scholar
BOND, W. J. 2008. What limits trees in C4 grasslands and savannas? Annual Review of Ecology, Evolution and Systematics 39:641659.CrossRefGoogle Scholar
BOND, W. J., MIDGLEY, G. F. & WOODWARD, W. I. 2003. The importance of low atmospheric CO2 and fire in promoting the spread of grasslands and savannas. Global Change Biology 9:973982.CrossRefGoogle Scholar
BOWMAN, D. M. J. S. 2000. Australian rainforests: islands of green in a sea of fire. Cambridge University Press, Cambridge. 357 pp.CrossRefGoogle Scholar
BOWMAN, D. M. J. S. & PANTON, W. J. 1993. Factors that control monsoon-rainforest seedling establishment and growth in north Australian Eucalyptus savanna. Journal of Ecology 81:297304.CrossRefGoogle Scholar
BRAITHWAITE, N. T. & MALLIK, A. U. 2012. Edge effects of wildfire and riparian buffers along boreal forest streams. Journal of Applied Ecology 49:192201.CrossRefGoogle Scholar
COCHRANE, M. A. 2003. Fire science for rainforests. Nature 421:913919.CrossRefGoogle ScholarPubMed
COLLIN, A., BERNARDIN, D. & SERO-GUILLAUME, O. 2011. A physical-based cellular automaton model for forest-fire propagation. Combustion Science and Technology 183:347369.CrossRefGoogle Scholar
DELVINGT, W., HEYMANS, J. C. & SINSIN, B. 1989. Guide du Parc National de la Pendjari. CECA-CEE-CEA, Brussels. 125 pp.Google Scholar
DUFRÊNE, M. & LEGENDRE, P. 1997. Species assemblages and indicator species: the need for a flexible asymmetrical approach. Ecological Monographs 67:345366.Google Scholar
FORTIN, M. J., KEITT, T. H., MAURER, B. A., TAPER, M. L., KAUFMAN, D. M. & BLACKBURN, T. M. 2005. Species’ geographic ranges and distributional limits: pattern analysis and statistical issues. Oikos 108:717.CrossRefGoogle Scholar
FURLEY, P. A. 1999. The nature and diversity of neotropical savanna vegetation with particular reference to the Brazilian cerrados. Global Ecology and Biogeography 8:223241.CrossRefGoogle Scholar
GEIGER, E. L., GOTSCH, S. G., DAMASCO, G., HARIDASAN, M., FRANCO, A. C. & HOFFMANN, W. A. 2011. Distinct roles of savanna and forest tree species in regeneration under fire suppression in a Brazilian savanna. Journal of Vegetation Science 22:312321.CrossRefGoogle Scholar
GIGNOUX, J., LAHOREAU, G., JULLIARD, R. & BAROT, S. 2009. Establishment and early persistence of tree seedlings in an annually burned savanna. Journal of Ecology 97:484495.CrossRefGoogle Scholar
GILPIN, M. E. & DIAMOND, J. M. 1982. Factors contributing to non-randomness in species co-occurrences on islands. Oecologia 52:7584.CrossRefGoogle ScholarPubMed
GOOD, S. P. & CAYLOR, K. K. 2011. Climatological determinants of woody cover in Africa. Proceedings of the National Academy of Sciences, USA 108:49024907.CrossRefGoogle ScholarPubMed
HENNENBERG, K., GOETZE, D., KOUAME, L., ORTHMANN, B. & POREMBSKI, S. 2005. Border and ecotone detection by vegetation composition along forest–savanna transects in Ivory Coast. Journal of Vegetation Science 16:301310.CrossRefGoogle Scholar
HIGGINS, S. I., BOND, W. J., FEBRUARY, E. C., BRONN, A., EUSTON-BROWN, D. I. W., ENSLIN, B., GOVENDER, N., RADEMAN, L., O'REGAN, S., POTGIETER, A. L. F., SCHEITER, S., SOWRY, R., TROLLOPE, L. & TROLLOPE, W. S. W. 2007. Effects of four decades of fire manipulation on woody vegetation structure in savanna. Ecology 88:11191125.CrossRefGoogle ScholarPubMed
HIROTA, M., NOBRE, C., OYAMA, M. D. & BUSTAMANTE, M. M. C. 2010. The climatic sensitivity of the forest, savanna and forest–savanna transition in tropical South America. New Phytologist 187:707719.CrossRefGoogle ScholarPubMed
HOFFMANN, W. A. & FRANCO, A. C. 2003. Comparative growth analysis of tropical forest and savanna woody plants using phylogenetically-independent contrasts. Journal of Ecology 91:475484.CrossRefGoogle Scholar
HOFFMANN, W. A., ORTHEN, B. & FRANCO, A. C. 2004. Constraints to seedling success of savanna and forest trees across the savanna–forest boundary. Oecologia 140:252260.CrossRefGoogle ScholarPubMed
HOFFMANN, W. A., ADASME, R., HARIDASAN, M., CARVALHO, M., GEIGER, E. L., PEREIRA, M. A. B., GOTSCH, S. G. & FRANCO, A. C. 2009. Tree topkill, not mortality, governs the dynamics of alternate stable states at savanna–forest boundaries under frequent fire in central Brazil. Ecology 90:13261337.CrossRefGoogle Scholar
HOFFMANN, W. A., JACONIS, S. Y., MCKINLEY, K. L., GEIGER, E. L., GOTSCH, S. G. & FRANCO, A. C. 2012a. Fuels or microclimate? Understanding the drivers of fire feedbacks at savanna–forest boundaries. Austral Ecology 37:634643.CrossRefGoogle Scholar
HOFFMANN, W. A., GEIGER, E. L., GOTSCH, S. G., ROSSATTO, D. R., SILVA, L. C. R., LAU, O. L., HARIDASAN, M. & FRANCO, A. C. 2012b. Ecological thresholds at the savanna–forest boundary: how plant traits, resources and fire govern the distribution of tropical biomes. Ecology Letters 15:759768.CrossRefGoogle ScholarPubMed
HOLDO, R. M. 2005. Stem mortality following fire in Kalahari sand vegetation: effects of frost, prior damage, and tree neighbourhoods. Plant Ecology 180:7786.CrossRefGoogle Scholar
HOLDO, R. M., HOLT, R. D. & FRYXELL, J. M. 2009. Grazers, browsers, and fire influence the extent and spatial pattern of tree cover in the Serengeti. Ecological Applications 19:95109.CrossRefGoogle ScholarPubMed
KELLMAN, M. 1984. Synergistic relationships between fire and low soil fertility in neotropical savannas: a hypothesis. Biotropica 16:158160.CrossRefGoogle Scholar
LLOYD, J., BIRD, M. I., VELLEN, L., MIRANDA, A. C., VEENENDAAL, E. M., DJAGBLETEY, G., MIRANDA, H. S., COOK, G. & FARQUHAR, G. D. 2008. Contributions of woody and herbaceous vegetation to tropical savanna ecosystem productivity: a quasi-global estimate. Tree Physiology 28:451468.CrossRefGoogle ScholarPubMed
MAGURRAN, A. E. & HENDERSON, P. A. 2003. Explaining the excess of rare species in natural species abundance distributions. Nature 422:714716.CrossRefGoogle ScholarPubMed
MIDGLEY, J. J., LAWES, M. J. & CHAMAILLE-JAMMES, S. 2010. Savanna woody plant dynamics: the role of fire and herbivory, separately and synergistically. Australian Journal of Botany 58:111.CrossRefGoogle Scholar
MURPHY, B. P. & BOWMAN, D. M. J. S. 2012. What controls the distribution of tropical forest and savanna? Ecology Letters 15:748758.CrossRefGoogle ScholarPubMed
NANGENDO, G., TER STEEGE, H. & BONGERS, F. 2006. Composition of woody species in a dynamic forest-woodland -savanna mosaic in Uganda: implications for conservation and management. Biodiversity and Conservation 15:14671495.CrossRefGoogle Scholar
NATTA, A. K. 2000. Tree species diversity assessment in riparian forests using remote sensing, geographic information systems and geostatistics (case study of Toui-Kilibo protected forest in Benin). M.Sc. thesis, ITC Forest Science Division, Enschede. 91 pp.Google Scholar
PAG2. 2005. Plan d'aménagement participatif et de gestion 2004–2013. Parc National de la Pendjari, Bénin. 83 pp.Google Scholar
RATNAM, J., BOND, W. J., FENSHAM, R. J., HOFFMANN, W. A., ARCHIBALD, S., LEHMANN, C. E. R., ANDERSON, M. T., HIGGINS, S. I. & SANKARAN, M. 2011. When is a ‘forest’ a savanna, and why does it matter? Global Ecology and Biogeography 20:653660.CrossRefGoogle Scholar
RAY, D., NEPSTAD, D. & MOUTINHO, P. 2005. Micrometeorological and canopy controls of fire susceptibility in a forested Amazon landscape. Ecological Applications 15:16641678.CrossRefGoogle Scholar
ROBERTS, D. W. 1986. Ordination on the basis of fuzzy set theory. Vegetatio 66:123131.CrossRefGoogle Scholar
RUSSELL-SMITH, J., STANTON, P. J., WHITEHEAD, P. J. & EDWARDS, A. 2004. Rain forest invasion of eucalypt-dominated woodland savanna, Iron Range, north-eastern Australia: I. Successional processes. Journal of Biogeography 31:12931303.CrossRefGoogle Scholar
SCHRÖDER, A., PERSSON, L. & DE ROOS, A. M. 2005. Direct experimental evidence for alternative stable states: a review. Oikos 110:319.CrossRefGoogle Scholar
SOKPON, N., AFFOUKOU, M., AMAHOWE, I., GANDJI, L., GNONLONFIN, L. & SOSSOU, B. 2008. Dynamique spatio-temporelle des formations végétales du Complexe Parc National de la Pendjari, zones cynégétiques de la Pendjari et de l'Atacora. Laboratoire d'études et de recherches forestières, FA/UP/République du Bénin. 59 pp.Google Scholar
STAVER, A. C., ARCHIBALD, S. & LEVIN, S. A. 2011. The global extent and determinants of savanna and forest as alternative biome states. Science 334:230232.CrossRefGoogle ScholarPubMed
STEVENS, J. T. & BECKAGE, B. 2009. Fire feedbacks facilitate invasion of pine savannas by Brazilian pepper (Schinus terebinthifolius). New Phytologist 184:365375.CrossRefGoogle Scholar
SWAINE, M. D., HAWTHORNE, W. P. & ORGLE, T. K. 1992. The effects of fire exclusion on savanna vegetation at Kpong, Ghana. Biotropica 24:166172.CrossRefGoogle Scholar
WHITE, F. 1983. The vegetation of Africa: a descriptive memoir to accompany the UNESCO/AETFAT/UNSO vegetation map of Africa. Natural Resources Research Report XX. UNESCO, Paris. 356 pp.Google Scholar
ZACHARIAS, M. A. & ROFF, J. C. 2001. Use of focal species in marine conservation and management: a review and critique. Aquatic Conservation: Marine and Freshwater Ecosystems 11:5976.CrossRefGoogle Scholar
ZUUR, A. F., IENO, E. N. & ELPHICK, C. S. 2010. A protocol for data exploration to avoid common statistical problems. Methods in Ecology and Evolution 1:112.CrossRefGoogle Scholar