Biogeosciences www.biogeosciences.net 1726-4170 1726-4189 6 8 2009 10.5194/bg-6-1825-2009 http://www.biogeosciences.net/6/1825/2009/ http://www.biogeosciences.net/6/1825/2009/bg-6-1825-2009.html http://www.biogeosciences.net/6/1825/2009/bg-6-1825-2009.pdf 1825 1838 2009-08-31 Conservation of soil organic carbon, biodiversity and the provision of other ecosystem services along climatic gradients in West Africa E. Marks G. K. S. Aflakpui J. Nkem R. M. Poch M. Khouma K. Kokou R. Sagoe M.-T. Sebastià Forest Technology Center of Catalonia (CTFC), Crta St Llorenç de Morunys km 2, 25280 Solsona, Spain Crops Research Institute (CSIR), P.O. Box 3785, Kumasi, Ghana Center for International Forestry (CIFOR), Situ Gede, Sindang Barang, Bogor Barat 16680, Indonesia University of Lleida, Rovira Roure 191, 25198 Lleida, Spain United Nations Office for Project Services (UNOPS), Regional Office for West and Central Africa, BP 15702 Dakar-Fann, Dakar, Senegal Laboratory of Botany and Ecology, Faculty of Sciences, Univ. of Lomé, BP 1515, Lomé, Togo Terrestrial carbon resources are major drivers of development in West Africa. The distribution of these resources co-varies with ecosystem type and rainfall along a strong Northeast-Southwest climatic gradient. Soil organic carbon, a strong indicator of soil quality, has been severely depleted in some areas by human activities, which leads to issues of soil erosion and desertification, but this trend can be altered with appropriate management. There is significant potential to enhance existing soil carbon stores in West Africa, with benefits at the global and local scale, for atmospheric CO₂ mitigation as well as supporting and provisioning ecosystem services. Three key factors impacting carbon stocks are addressed in this review: climate, biotic factors, and human activities. Climate risks must be considered in a framework of global change, especially in West Africa, where landscape managers have few resources available to adapt to climatic perturbations. Among biotic factors, biodiversity conservation paired with carbon conservation may provide a pathway to sustainable development, and biodiversity conservation is also a global priority with local benefits for ecosystem resilience, biomass productivity, and provisioning services such as foodstuffs. Finally, human management has largely been responsible for reduced carbon stocks, but this trend can be reversed through the implementation of appropriate carbon conservation strategies in the agricultural sector, as shown by multiple studies. Owing to the strong regional climatic gradient, country-level initiatives will need to consider carbon sequestration approaches for multiple ecosystem types. Given the diversity of environments, global policies must be adapted and strategies developed at the national or sub-national levels to improve carbon storage above and belowground. Initiatives of this sort must act locally at farmer scale, and focus on ecosystem services rather than on carbon sequestration solely. Adepetu, J. A.: Soil fertility management and sustainable farming systems, National Agricultural Land Development Authority Workshop, Mena, Nigeria, 1994. Badejo, M. A.: Agroecological restoration of savanna ecosystems, Ecol. Eng., 10, 209–219, 1998. Bationo, A., Kihara, J., Vanlauwe, B., Waswa, B., and Kimetu, J.: Soil organic carbon dynamics, functions and management in West African agro-ecosystems, Agr. Syst., 94, 13–25, 2007. Batjes, N. H.: Total carbon and nitrogen in the soils of the world, Eur. J. Soil Sci., 47, 151–163, 1996. Batjes, N. H.: Options for increasing carbon sequestration in West African soils: An exploratory study with special focus on Senegal, Land Degrad. Dev., 12, 131–142, 2001. Batjes, N. H.: Estimation of soil carbon gains upon improved management within croplands and grasslands of Africa. Environ. Dev. Sustain., 6, 133–143, 2004. Batjes, N. H. and Bridges, E. M.: A review of soil factors and processes that control fluxes of heat, moisture and greenhouse gases. International Soil Reference and Information Centre, Wageningen, The Netherlends, 192 pp., 1992. Brümmer, C., Papen, H., Wassmann, R., and Brüggemann, N.: Fluxes of CH₄ and CO₂ from soil and termite mounds in south Sudanian savannaof Burkina Faso (West Africa), Global Biochem. Cy., 23, GB1001, doi:10.1029/2008GB003237, 2009. Buerkert, A., Bationo, A., and Dossa, K.: Mechanisms of residue mulch-induced cereal growth increases in West Africa, Soil Sci. Soc. Am. J., 64, 346–358, 2000. Canadell, J. G., Kirschbaum, M. U., Kurz, W. A., Sanz, M. J., Schlamadinger, B., and Yamagata, Y.: Factoring out natural and indirect human effects on terrestrial carbon sources and sinks, Environ. Sci. Policy, 10, 370–384, 2007. Chapin III, F. S., Walker, B. H., Hobbs, R. J., Hooper, D. U., Lawton, J. H., Sala, O. E., and Tilman, D.: Biotic control over the functioning of ecosystems, Science, 277, 500–504, 1997. Costanza, R., Fisher, B., Mulder, K., Liu, S., and Christopher, T.: Biodiversity and ecosystem services: a multi-scale empirical study of the relationship between species richness and net primary production, Ecol. Econ., 61, 478–491, 2007. Craswell, E. T. and Lefroy, R. D. B.: The role and function of organic matter in tropical soils, Nutr. Cycl. Agroecosys., 61, 7–18, 2001. de Bello, F., Leps, J., and Sebastià, M.-T.: Predictive value of plant traits to grazing along a climatic gradient in the Mediterranean, J. Appl. Ecol., 42, 824–833, 2005. de Bello, F., Leps, J., and Sebastià, M.-T.: Variations in species and functional plant diversity along climatic and grazing gradients, Ecography, 29, 801–810, 2006. De Deyn, G. B., ~Cornelissen, J. H., and Bardgett, R. D.: Plant functional traits and soil carbon sequestration in contrasting biomes, Ecol. Lett., 11. 516–531, 2008 Diaz, S., Wardle, D. A., and Hector, A.: Incorporating biodiversity in climate change mitigation initiatives, Seasonally Dry Tropical Forest Symposium, Stanford, Palo Alto, USA, 2001. Diaz, S., Lavorel, S., de Bello, F., Quetier, F., Grigulis, K., and Robson, T. M.: Incorporating plant functional diversity effects in ecosystem service assessments, P. Natl. Acad. Sci. USA, 104, 20684–20689, 2007. Doraiswamy, P. C., McCarty, G. W., Hunt, J., Yost, R. S., Doumbia, M., and Franzluebbers, A. J.: Modeling soil carbon sequestration in agricultural lands of Mali, Agr. Syst., 94, 63–74, 2006. Doumbia, M., Jarju, A., Sène, M., Traoré, K., Yost, R., Kablan, R., Brannan, K., Berthe, A., Yamoah, C., Querido, A., Traoré, P. C. S., and Ballo, A.: Sequestration of organic carbon in West African soils by Aménagement en Courbes de Niveau, Agron. Sustain. Dev., 29, 267–275, 2008. Elberling, B., Toure, A., Rasmussen, K.: Changes in soil organic matter following groundnut-millet cropping at three locations in semi-arid Senegal, West Africa, Agr. Ecosyst. Environ., 96, 37-47, 2003. Eswaran, H., Reich, P. F., Kimble, J. M., Beinroth, F., Padmanabhan E., and Moncharoen, P.: Global carbon stocks, in: Global climate change and pedogenic carbonates, edited by: Lal R., Kimble J. M., Eswaran H., Stewart B. H., Lewis, Boca Raton, USA, 15–26, 1999. Eswaran, H., van den Berg, E., and Reich, P.: Organic carbon in soils of the world, Sol. Sci. Soc. Am. J., 57, 192–154, 1993. Friedlingstein, P., Cadule, P., Piao, S. L., Ciais, P., and Sitch, S.: The African contribution to the global climate-carbon cycle feedback of the 21st century, Biogeosciences Discuss., 5, 4847–4866, 2008. GEF (Global Environment Facility), and IFAD (International Fund for Agricultural Development), Tracking land degradation and desertification, GEF and IFAD Partnership, 2002. Giardina, C. P. and Ryan M. G.: Evidence that decomposition rates of organic carbon in mineral soil do not vary with temperture, Nature, 404, 858–861, 2000. Guo, L. B. and Gifford, R. M.: Soil carbon stocks and land use change: a meta analysis, Glob. Change Biol., 8, 345–360, 2002. Hien, E., Ganry, F., and Oliver, R.: Carbon sequestration in a savannah soil in southwestern Burkina as affected by cropping and cultural practices, Arid Land Res. Manag., 20, 133–146, 2006. Holmgren, M. and Poorter, L.: Does a ruderal strategy dominate the endemic flora of the West African forests?, J. Biogeogr., 34, 1100–1111, 2007. Hollingsworth, T. N., Schuur, E. A. G., Chapin III, F. S., and Walker, M. D.: Plant community composition as a predictor of regional soil carbon storage in Alaskan boreal black spruce ecosystems, Ecosystems, 11, 629–642, 2008. Hooper, D. U., Chapin III, F. S., Ewel, J. J., Hector, A., Inchausti, P., Lavorel, S., Lawton, J. H., Lodge, D. M., Loreau, M., Naeem, S., Schmid, B., Setala, H., Symstad, A. J., Vandermeer, J., and Wardle, D. A.: Effects of biodiversity on ecosystem functioning: A consensus of current knowledge, Ecol. Monogr., 75, 3–35, 2005. Houghton, R. A., Boone, R. D., Fruci, J. R., Hobbie, J. E., Melillo, J. M., Palm, C. A., Peterson, B. J., Shaver, G. R., Woodwell, G. M., Moore, B., Sloke, D. L., and Myers, N.: The flux of carbon from terrestrial ecosystems to the atmosphere in 1980 due to changes in land use: geographic distribution of the global flux, Tellus, 39(B), 122–139, 1987. IPCC (Intergovernmental Panel on Climate Change): Climate change 2007: impacts, adaptation and vulnerability: Working Group II contribution to the Fourth Assessment Report of the IPCC Intergovernmental Panel on Climate Change, IPCC Secretariat, 1000 pp., 2007. Jenik, J.: The Dahomey gap: an important issue in african phytogeography, Memoirs of the Society for Biogeography, 3, 125–133, 1994. Jordan C. F.: Productivity of tropical rain forest ecosystems and the implications for their use as future wood and energy sources, in: Tropical rain forest ecosystems, edited by: Golley F. B., Lieth H., Werger M. J. A., Elsevier Scientific Pub. Co., New York, USA, 117–132, 1983. Kirschbaum, M. U. F.: The temperature dependence of soil organic matter, and the effect of global warming on soil organic C storage, Soil Biol. Biochem. 27, 753–760, 1995. Kirwan, L., Luescher, A., Sebastià, M.-T., Finn, J. A., Collins, R. P., Porqueddu, C., Helgadottir, A., Baadshaug, O. H., Brophy, C., Coran, C., Dalmannsdottir, S., Delgado, I., Elgersma, A., Fothergill, M., Frankow Lindberg, B. E., Golinski, P., Grieu, P., Gustavsson, A. M., Hoglind, M., Huguenin Elie, O., Iliadis, C., Jorgensen, M., Kadziuliene, Z., Karyotis, T., Lunnan, T., Malengier, M., Maltoni, S., Meyer, V., Nyfeler, D., Nykanen, K. P., Parente, J., Smit, H. J., Thumm, U., and Connolly, J.: Evenness drives consistent diversity effects in intensive grassland systems across 28 European sites, J. Ecol., 95, 530–539, 2007. Lal, R. and Bruce, J. P.: The potential of world cropland soils to sequester C and mitigate the greenhouse effect, Environ. Sci. Pol., 2, 177–185, 1999. Lal, R.: Potential of desertification control to sequester carbon and mitigate the greenhouse effect, Clim. Change, 51, 35–72, 2001. Lal, R.: The potential of soils of the tropics to sequester carbon and mitigate the green house effect, Adv. Agron., 76, 1–30, 2002. Lal, R.: Global potential of soil carbon sequestration to mitigate the greenhouse effect, Crit. Rev. Plant Sci., 22, 151–184, 2003. Lal, R.: Soil carbon sequestration impacts on global climate change and food security, Science, 304, 1623–1627, 2004. Lal, R.: Soil carbon sequestration in natural and managed tropical forest ecosystems, J. Sustainable Forestry, 21, 1–30, 2005. Larwanou, M., Abdoulaye, M., and Reij, C.: Etude de la régénération naturelle assistée dans la région de Zinder (Niger), USAID/EGAT, IRG, Washington, USA, 56 pp., 2006. Latham, M. and Dugerdil, M.: Contribution à l'étude de l'influence du sol sur la végétation au contact forêt-savane dans l'ouest et le centre de la Côte d'Ivoire, Adansonia, 2, 553–576, 1970. Liu, S., Kaire, M., Wood, E., Diallo, O., and Tieszen, L. L.: Impacts of land use and climate change on carbon dynamics in south-central Senegal, J. Arid. Environ., 59, 583–604, 2004. Loreau, M., Naeem, S., Inchausti, P., Bengtsson, J., Grime, J. P., Hector, A., Hooper, D. U., Huston, M. A., Raffaelli, D., Schmid, B., Tilman, D., and Wardle, D. A.: Biodiversity and ecosystem functioning: current knowledge and future challenges, Science, 294, 804–808, 2001. Millennium Ecosystem Assessment: Ecosystems and human well-being, Island Press, Washington DC, USA, 137 pp., 2005. Milton, S. J. and Dean, W. R.: A conceptual model of arid rangeland degradation, Bioscience, 44, 70–76, 1994. Mittelbach, G. G., Steiner, C. F., Scheiner, S. M., Gross, K. L., Reynolds, H. L., Waide, R. B., Willig, M. R., Dodson, S. I., and Gough, L.: What is the observed relationship between species richness and productivity?, Ecology, 82, 2381–2396, 2001. Mittermeier, R. A.: Hotspots revisited, Cemex, Mexico City, Mexico, 392 pp., 2004. Niasse, M., Afouda, N., and Amani, A.: Reducing West Africa's vulnerability to climate impacts on water resources, wetlands and desertification. Elements for a regional strategy for preparedness and adaptation, IUCN-The World Conservation Union, 66 pp., 2004. Palm, C. A., Myers, R. J. K., and Nandwa, S. M.: Combined use of organic and inorganic nutrient sources for soil fertility maintenance and replenishment, in: Replenishing soil fertility in Africa, edited by: Buresh R. J., Sanchez P. A., Calhoun F., SSSA, Spec. Pub. 51. Madison, WI, SSSA, 47–61, 1997. Parton, W., Tappan, G., Ojima, D., and Tschakert P.: Ecological impact of historical and future land-use patterns in Senegal, J. Arid Environ, 59, 605–623, 2004. Paustian, K., Andrén, O., Janzen, H. H., Lal, R., Smith, P., Tian, G., Tiessen, H., Van Noordwijk, M., and Woomer, P. L.: Agricultural soils as a sink to mitigate CO₂ emissions, Soil Use Manage., 13, 230–244, 1997. Perez, C., Roncoli, C., Neely, C., and Steiner, J. L.: Can carbon sequestration markets benefit low-income producers in semi-arid Africa? Potentials and challenges, Agr. Syst., 94, 2–-12, 2007. Pieri, C.: Long-Term Soil Management Experiments in Semiarid Francophone Africa. RC Press, Boca Raton, FL, USA, 225–266, 1995. Poch, R. M. and Ubalde, J. M.: Diagnostic of degradation processes of soils from northern Togo (West Africa) as a tool for soil and water management, Workshop IC-PLR 2006, 2006. Raupach, M. R., G. Marland, P. Ciais, C. Le Quéré, J. G. Canadell, and C. B. Field.: Global and Regional drivers of accelerating CO2 emissions. P. Natl. Acad. Sci. USA, 104(24), 10288–10293, 2007. Reich, P., Walters, M. B., and Ellsworth, D. S.: From tropics to tundra: Global convergence in plant functioning, P. Natl. Acad. Sci. USA, 94, 13730–13734, 1997. Ringius, L.: Soil carbon sequestration and the CDM: Opportunities and challenges for Africa, Clim. Change, 54, 471–495, 2002. Rodriguez, J. P., Beard, T. D., Bennett, E. M., Cumming, G. S., Cork, S. J., Agard, J., Dobson, A. P., and Peterson, G. D.: Trade-offs across space, time, and ecosystem services, Ecol. Soc., 11(1), art. no. 28, 2006. Roose, E. and Bathes, B.: Organic matter management for soil conservation and productivity restoration in Africa: a contribution from Francophone research, Nutr. Cycl. Agroecosys., 61, 159–170, 2001. Rustad, L. E., Campbell, J. L., Marion G. M., Norby, R. J., Mitchell, M. J., Hartley, A. E., Cornelissen, J. H. C., and Gurevitch J.: A meta-analysis of the response of soil respiration, net nitrogen mineralization, and aboveground plant growth to experimental ecosystem warming, Oecologia 126, 543–562, 2001. Schlesinger, W. H.: Carbon sequestration in soils: some cautions amidst optimism, Agr. Ecosyst. Environ., 82, 121–127, 2000. Schulze, E. D.: Biological control of the terrestrial carbon sink, Biogeosciences, 3, 147–166, 2006. Sebastià, M.-T.: Plant guilds drive biomass response to global warming and water availability in subalpine grassland, J. Appl. Ecol., 44, 158–167, 2007. Sebastià, M.-T., Kirwan, L., and Connolly, J.: Strong shifts in plant diversity and vegetation composition in grassland shortly after climatic change, J. Veg. Sci., 19, 299–306, 2008. Sebastià, M.-T., Marks, E., and Poch, R. M.: Soil carbon and plant diversity distribution at the farm level in the savannah region of Northern Togo (West Africa), Biogeosciences Discuss., 5, 4107-4127, 2008. Skjemstad, J. O., Reicosky, D. C., Wilts, A. R., and McGowan, J. A.: Charcoal carbon in US agricultural soils, Sol. Sci. Soc. Am. J., 66, 1249–1255, 2002. Smaling, E. and Dixon, J.: Adding a soil fertility dimension to the global farming systems approach, with cases from Africa, Agr. Ecosyst. Environ., 116, 15–26, 2006. Stewart, C. E., Paustian, K., Conant, R. T., Plante, A. F., and Six, J.: Soil carbon saturation: concept, evidence and evaluation, Biogeochemistry, 86, 19–31, 2007. Thornley, J. H. M. and Cannell, M. G. R.: Soil carbon storage response to temperature: an hypothesis, Ann. Bot.-London, 87, 591–598, 2001. Tiessen, H., Feller, C., Sampaio, E. V. S. B., and Garin, P.: Carbon sequestration and turnover in semiarid savannas and dry forest, Clim. Change, 40, 105–117, 1998. Tieszen, L. L., Tappan, G. G. and Touré, A.: Sequestration of carbon in soil organic matter in Senegal: an overview, J. Arid Environ., 59, 409–425, 2004. Tilman, D., Wedin, D., and Knops, J.: Productivity and sustainability influenced by biodiversity in grassland ecosystems, Nature 379, 718–720, 1996. Tilman, D., Hill, J., and Lehman, C. L.: Carbon-negative biofuels from low-input high-diversity grassland biomass, Science, 314, 1598–1600, 2006. Traoré, P. C. S., Bostick, W. M., Jones, J. W., Koo, J., Go\"ıta, K., and Bado, B. V.: A simple soil organic model for biomass data assimilation in community-level carbon contracts, Ecol. Appl., 18, 624–636, 2008. Trumbore, S. E.: Potential responses of soil organic carbon to global environmental change, P. Natl. Acad. Sci. USA, 94, 8284–8291, 1997. Tschakert, P.: Environmental services and poverty reduction: options for smallholders in the Sahel, Agr. Syst., 94, 75–86, 2007. Tschakert, P., Khouma, M., and Sene, M.: Biophysical potential for soil carbon sequestration in agricultural systems of the Old Peanut Basin of Senegal, J. Arid. Environ., 59, 511–533, 2004. Tschakert, P. and Tappan, G.: The social context of carbon sequestration: considerations from a multi-scale environmental history of the Old Peanut Basin of Senegal, J. Arid Environ., 59, 535–564, 2004 UNEP (United Nations Environment Programme): Global environment outlook: environment for development, United Nations Environment Program Office, Nairobi, 2007. Unruh, J. D., Houghton, R. A., and Lefebvre, P. A.: Carbon storage in agroforestry: an estimate for sub-Saharan Africa, Climate Res., 3, 39–52, 1993. Vagen, T. G., Lal, R., and Singh, B. R.: Soil carbon sequestration in sub-Saharan Africa: a review, Land Degrad. Dev., 16, 53–71, 2005. Van der Werf, E. J.: Ecologically sustainable agriculture as an effective means to combat desertification in tropical Africa: the case of agriculture in Accra Plains (Ghana). Stichting Mondiaal Alternatief, Zandvoort, 25 pp., 1983. White, F.: Vegetation of Africa: a descriptive memoir to accompany the UNESCO/AETFAT/UNSO vegetation map of Africa, UNESCO, 356 pp., 1983. Woomer, P. L., Tieszen, L. L., Tappan, G., Toure, A., and Sall, M.: Land use change and terrestrial carbon stocks in Senegal, J. Arid. Environ., 59, 625–642, 2004a. Woomer, P. L., Touré, A., and Sall, M.: Carbon stocks in Senegal's Sahel Transition Zone, J. Arid Environ., 59, 499–510, 2004b. Zech, W., Senesi, N., Guggenberger, G., Kaiser, K., Lehmann, J., Miano, T. M., Miltner, A., and Schroth, G.: Factors controlling humification and mineralization of soil organic matter in the tropics, Geoderma, 79, 117–162, 1997.