Regional Environmental Change

, Volume 6, Issue 3, pp 147–156

Hydrologic and land use impacts on vegetation growth and NPP at the watershed scale in a semi-arid environment

  • N. Boulain
  • B. Cappelaere
  • L. Séguis
  • J. Gignoux
  • C. Peugeot
Original article

Abstract

Significant, adverse climatic change and drastically increased demographic pressure have strongly affected, in recent years, the hydrology and environment in the semi-arid Sahel region of West Africa. Marked rain deficits have coincided with increased water runoff, meaning less water availability for the vegetation. Conversely, changes in vegetation cover have had strong repercussions on the hydrologic cycle. To study these phenomena, the coupling of two explicit, process-based models, of catchment hydrology and of mixed vegetation cover, respectively, has been undertaken and applied to a 2 km2 site in Niger. Some of the first significant results are presented herein. Some are consistent with intuitive judgments that can be made in the absence of a coupled model, others are much less so and show that representation through model coupling of hydrosphere/biosphere interactions is essential to produce more reliable analyses and projections. In particular, it is found that the relation of biomass productivity to rainfall under this dry, water-limited climate is not as straightforward as one would expect, more specifically, that its main control may not be the total season rainfall.

Keywords

Millet Savanna West Africa Climate change 

References

  1. Alverson K, Bradley R, Pedersen T (2001) Environmental variability and climate change, Rep. No. 3. IGBP, StockholmGoogle Scholar
  2. Bonan GB, Levis S, Sitch S, Vertenstein M, Oleson KW (2003) A dynamic global vegetation model for use with climate models: concepts and description of simulated vegetation dynamics. Global Change Biol 9:1543–1566CrossRefGoogle Scholar
  3. Boulain N (2004) Effet des facteurs climatiques et anthropiques dans l’évolution récente des écosystèmes tropicaux: modélisation spatialisée du bilan hydrique d’un petit bassin versant sahélien. PhD, Paris VI, ParisGoogle Scholar
  4. Cappelaere B, Peugeot C, Seguis L, Maia A, Vieux BE (2003a) Associer données et modèle incertains: une expériene en petit bassin sahélien. In: Servat E, Najen W, Leduc C, Shakeel C (eds) Hydrology of the Mediterranean and semiarid regions, vol 278. IAHS, UK, pp 151–156Google Scholar
  5. Cappelaere B, Vieux BE, Peugeot C, Maia A, Seguis L (2003b) Hydrologic process simulation of a semiarid, endoreic catchment in Sahelian West Niger. 2. Model calibration and uncertainty characterization. J Hydrol 279:244–261CrossRefGoogle Scholar
  6. Charney J, Stone PH, Quirk WJ (1975) Drought in Sahara—biogeophysical feedback mechanism. Science 187:434–435CrossRefGoogle Scholar
  7. Collatz GJ, Ribascarbo M, Berry JA (1992) Coupled photosynthesis-stomatal conductance model for leaves of C4 plants. Aust J Plant Physiol 19:519–538CrossRefGoogle Scholar
  8. Cuenca RH, Brouwer J, Chanzy A, Droogers P, Galle S, Gaze SR, Sicot M, Stricker H, Angulo-Jaramillo R, Boyle SA (1997) Soil measurements during HAPEX-Sahel intensive observation period. J Hydrol 188–189:224–266CrossRefGoogle Scholar
  9. D’Amato, Lebel NT (1998) On the characteristics of the rainfall events in the Sahel with a view to the analysis of climatic variability. Int J Climatol 18:955–974CrossRefGoogle Scholar
  10. Delabre E (1998) Caractérisation et évolution d’écosystèmes anthropisés Sahéliens: les milieux post-culturaux du sud-ouest nigérien. Paris VI, ParisGoogle Scholar
  11. d’Herbes JM, Valentin C (1997) Land surface conditions of the Niamey region: ecological and hydrological implications. J Hydrol 188–189:18–42CrossRefGoogle Scholar
  12. Dunne T (1978) Field studies of hillslope flow processes. In: Kirkby MJ (ed) Hillslope hydrology. Wiley-Interscience, New York, pp 227–293Google Scholar
  13. Farquhar GD, Von caemmerer S, Berry JA (1980) A biochemical model of photosynthetic CO2 assimilation in leaves of C3 species. Planta 149:78–90CrossRefGoogle Scholar
  14. Foley JA, Levis S, Prentice IC, Pollard D, Thompson SL (1998) Coupling dynamic models of climate and vegetation. Global Change Biol 4:561–579CrossRefGoogle Scholar
  15. Fraser GW, Canham CD, Lertzman KP (1999) Gap Light Analyser (GLA): imaging software to extract canopy structure and gap light transmission indices from true-colour fisheye photographs, users manual and program documentation. Simon Fraser University/the Institute of Ecosystem studies, British Columbia/MillbrookGoogle Scholar
  16. Goutorbe JP, Lebel T, Tinga A, Bessemoulin P, Brouwer J, Dolman AJ, Engman ET, Gash JHC, Hoepffner M, Kabat P, Kerr YH, Monteny B, Prince S, Said F, Sellers P, Wallace JS (1994) Hapex-Sahel—a large-scale study of land–atmosphere interactions in the semiarid tropics. Ann Geophys Atmos Hydrosph Space Sci 12:53–64Google Scholar
  17. Goutorbe JP, Lebel T, Dolman AJ, Gash JHC, Kabat P, Kerr YH, Monteny B, Prince SD, Stricker JNM, Tinga A, Wallace JS (1997a) An overview of HAPEX-Sahel: a study in climate and desertification. J Hydrol 189:4–17CrossRefGoogle Scholar
  18. Goutorbe JP, Noilhan J, Lacarrere P, Braud I (1997b) Modelling of the atmospheric column over the central sites during HAPEX-Sahel. J Hydrol 189:1017–1039CrossRefGoogle Scholar
  19. Lebel T, Taupin JD, Damato N (1997) Rainfall monitoring during HAPEX-Sahel. 1. General rainfall conditions and climatology. J Hydrol 189:74–96CrossRefGoogle Scholar
  20. Leduc C, Favreau G, Schroeter P (2001) Long-term rise in a sahelian water-table: the continental terminal in south-west Niger. J Hydrol 243:43–54CrossRefGoogle Scholar
  21. Le Houerou HN, Bingham RL, Skerbek W (1988) Relationship between the variability of primary production and the variability of annual precipitation in world arid lands. J Arid Environ 15:1–18Google Scholar
  22. de Noblet-Ducoudre N, Claussen R, Prentice C (2000) Mid-Holocene greening of the Sahara: first results of the GAIM 6000 year BP experiment with two asynchronously coupled atmosphere/biome models. Clim Dyn 16:643–659CrossRefGoogle Scholar
  23. Peugeot C, Cappelaere B, Vieux BE, Seguis L, Maia A (2003) Hydrologic process simulation of a semiarid, endoreic catchment in Sahelian West Niger. 1. Model-aided data analysis and screening. J Hydrol 279:224–243CrossRefGoogle Scholar
  24. Poissonet J, Chambris F, Touré I (1992) Equilibre et déséquilibre des phytocénosese herbacées sahéliens. Influence de la pluviositée et de la proximitée des points d’eau. In: LeFloc’h E, Grouzis M, Cornet A, Bille J-C (eds) L’Aridité une contrainte au développement. Caractérisation, Réponses biologique, Stratégie des sociétés. ORSTOM, Paris, p 597Google Scholar
  25. Reyniers FN (1990) La pluie n’est pas le seul remède à la sécheresse en Afrique. Sécheresse 1:36–39Google Scholar
  26. SAS (1990) SAS/STAT user’s guide. SAS Institute, CaryGoogle Scholar
  27. Scanlon TM, Albertson JD, Caylor KK, Williams CA (2002) Determining land surface fractional cover from NDVI and rainfall time series for a savanna ecosystem. Remote Sens Environ 82:376–388CrossRefGoogle Scholar
  28. Séguis L, Cappelaere B, Peugeot C, Vieux B (2002) Impact on Sahelian runoff of stochastic and elevation-induced spatial distributions of soil parameters. Hydrol Process 16:313–332CrossRefGoogle Scholar
  29. Séguis L, Cappelaere B, Milesi G, Peugeot C, Massuel S, Favreau G (2004) Assessing the impacts of climate and land-clearing on runoff in a small Sahelian catchment (South West Niger). Hydrol Process 16:313–332CrossRefGoogle Scholar
  30. Simioni G (2001) Importance de la structure spatiale de la strate arborée sur le fonctionnements carboné et hydrique des écosystèmes herbes-arbres. Exemple d’une savane d’Afrique de l’Ouest. PhD, Paris XI Orsay, ParisGoogle Scholar
  31. Simioni G, Gignoux J, Le Roux X (2003) Tree layer spatial structure can affect savanna production and water budget: results of a 3-D model. Ecology 84:1879–1894CrossRefGoogle Scholar
  32. Taylor CM, Lambin EF, Stephenne N, Harding RJ, Essery RLH (2002) The influence of land use change on climate in the Sahel. J Clim 15:3615–3629CrossRefGoogle Scholar
  33. Texier D, de Noblet N, Harrison SP, Haxeltine A, Jolly D, Joussaume S, Laarif F, Prentice IC, Tarasov P (1997) Quantifying the role of biosphere–atmosphere feedbacks in climate change: coupled model simulations for 6000 years BP and comparison with palaeodata for northern Eurasia and northern Africa. Clim Dyn 13:865–882CrossRefGoogle Scholar
  34. USACE (1993) Grass 4.1 user’s reference manual. USACE, ChampaignGoogle Scholar
  35. Vieux BE (2001) Distributed hydrologic modeling using GIS. Kluwer Academic, New YorkGoogle Scholar
  36. Vieux BE Gaur N (1994) Finite-element modeling of storm water runoff using Grass GIS. Microcomput Civil Eng 9:263–270CrossRefGoogle Scholar
  37. Wang GL, Eltahir EAB (2000) Biosphere–atmosphere interactions over West Africa. I: development and validation of a coupled dynamic model. Q J R Meteorol Soc 126:1239–1260CrossRefGoogle Scholar
  38. Wezel A, Schlecht E (2004) Inter-annual variation of species composition of fallow vegetation in semi-arid Niger. J Arid Environ 56:265–282CrossRefGoogle Scholar

Copyright information

© Springer-Verlag 2006

Authors and Affiliations

  • N. Boulain
    • 1
    • 2
  • B. Cappelaere
    • 2
  • L. Séguis
    • 3
  • J. Gignoux
    • 1
  • C. Peugeot
    • 3
  1. 1.Fonctionnement et Evolution des Systèmes Ecologiques, UMR 7625Ecole Normale SupérieureParis cedex 05France
  2. 2.Institut de Recherche pour le Développement (IRD)U.M.R. HydrosciencesMontpellier cedex 5France
  3. 3.Institut de Recherche pour le Développement (IRD)U.M.R. HydrosciencesCotonou AeroportBenin

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