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The Map Is not the Territory: How Satellite Remote Sensing and Ground Evidence Have Re-shaped the Image of Sahelian Desertification

Part of the Springer Earth System Sciences book series (SPRINGEREARTH)

Abstract

Satellite remote sensing, in particular the analysis of coarse resolution time series of vegetation indices, has played an important role in challenging earlier assumptions of widespread desertification in the Sahel. Findings of such analyses show a greening trend in much of the region since the early 1980s, which seems to suggest a positive development. On the other hand, a growing number of field studies of vegetation dynamics across the Sahel offer a more fine-scaled and nuanced picture of changes. Of particular interest with respect to degradation and rehabilitation is the woody component of the vegetation cover, which is less affected by short-term fluctuations in precipitation than the herbaceous component. We synthesized findings from published field studies on changes in the abundance and diversity of woody vegetation across the Sahel and spatially compared them with the remotely sensed greenness trends. Many field sites reported a decline in the abundance of woody vegetation since before the great droughts, in particular of large trees. In addition, the woody vegetation shifted from a diverse species composition towards fewer and more drought tolerant species in the majority of sites. However, some success stories of agroforestry management stood out as well, where formerly degraded farmlands were rehabilitated and in some cases have reached even higher tree densities than in the 1960s. The discrepancy between satellite-observed greening trends and changes in woody vegetation on the ground—in both directions—emphasizes the need of integrating multiple perspectives and scales in the interpretation of greening trends with respect to desertification.

Keywords

  • Remote sensing
  • Time series
  • (Re-)greening
  • Tree cover
  • Ground truthing
  • Longitudinal studies
  • Size class distributions
  • Local knowledge

“The Map is not the Territory” is an aphorism that goes back to the Polish-American scientist Alfred Korzybski and emphasizes that a representation of reality (=map) must not be confused with reality itself (=territory). Thus, maps and graphical data convey images that risk developing a life of their own, with the map preceding and even becoming the territory.

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Notes

  1. 1.

    Although the term “ground truth” is widely used in the remote sensing community to describe field observations that help interpret remote sensing imagery, it is disliked by many remote sensing scientists, because it might imply that satellite data are erroneous in some way and because reference data can come from sources not necessarily involving ground investigations. Despite its shortcomings, we use this term here for lack of a better and equally short alternative.

  2. 2.

    Since the NOAA AVHRR NDVI time series from 1981 to present combines observations from two different sensors flown on a series of fourteen satellites, inter-sensor calibration and bias correction for orbital drifts are prerequisites for the creation of long term stable NDVI time series (Pinzon and Tucker 2014). Much of the time series development has been done by the Global Inventory Modeling and Mapping Studies (GIMMS) group. As calibration and correction algorithms have evolved over time, each generation of the GIMMS NDVI time series shows slight differences from the previous one. One of the authors of this chapter compared trends of the most recent 3rd generation GIMMS NDVI with trends of the previous 2nd generation and found considerable differences in the spatial patterns of those trends for West Africa over an identical time period. Such differences, which are explained by data preprocessing alone, call into question the interpretability of NDVI trends from the NOAA AVHRR time series with respect to land degradation and desertification.

References

  • Akpo, L.-E. (1997). Phenological interactions between tree and understory herbaceous vegetation of a Sahelian semi-arid savanna. Plant Ecology, 131, 241–248.

    CrossRef  Google Scholar 

  • Anyamba, A., Small, J. L., Tucker, C. J., & Pak, E. W. (2014). Thirty-two years of Sahelian Zone growing season non-stationary NDVI3 g patterns and trends. Remote Sensing, 6, 3101–3122.

    CrossRef  Google Scholar 

  • Anyamba, A., & Tucker, C. J. (2005). Analysis of Sahelian vegetation dynamics using NOAA-AVHRR NDVI data from 1981–2003. Journal of Arid Environments, 63, 596–614.

    CrossRef  Google Scholar 

  • Aubréville, A. (1938). La forêt coloniale. Annals of the Academy Science Colon, 9, 1–245.

    Google Scholar 

  • Ayantunde, A. A., Briejer, M., Hiernaux, H., Henk, M., Udo, J., & Tabo, R. (2008). Botanical knowledge and its differentiation by age, gender and ethnicity in south western Niger. Human Ecology, 36, 881–889.

    CrossRef  Google Scholar 

  • Bai, Z. G., Dent, D. L., Olsson, L., & Schaepman, M. E. (2008). Global assessment of land degradation and improvement 1: Identification by remote sensing. Report 2008/01, FAO/ISRIC—Rome/Wageningen.

    Google Scholar 

  • Beck, L. R., Hutchinson, C. F., & Zauderer, J. (1990). A comparison of greenness measures in two semi-arid grasslands. Climatic Change, 17, 287–303.

    CrossRef  Google Scholar 

  • Belemvire, A. (2003). Impact de la conservation de l’eau et des sols sur la régénération naturelle assistée. Développement rural et environnement au Burkina Faso: La réhabilitation de la capacité des terroirs sur la partie Nord du Plateau central entre 1980 et 2000. Rapport de travail no. 1. .Ouagadougou, Burkina Faso: Conseil National pour la Gestion de l’Environnement.

    Google Scholar 

  • Bognounou, F., Thiombiano, A., Savadogo, P., Boussim, J. I., Oden, P. C., & Guinko, S. (2009). Woody vegetation structure and composition at four sites along a latitudinal gradient in Western Burkina Faso. Bois et Forêts des Tropiques, 300, 29–44.

    Google Scholar 

  • Botoni, E., & Reij, C. (2009). La transformation silencieuse de l’environnement et des systèmes de production au Sahel: L’impacts des investissements publics et privés dans la gestion des ressources naturelles. Amsterdam, the Netherlands: Comité Permanent Inter-Etats de Lutte Contre la Secheresse dans le Sahel (CILSS) and Vrije University Amsterdam.

    Google Scholar 

  • Cappelaere, B., Descroix, L., Lebel, T., Boulain, N., Ramier, D., Laurent, J. P., et al. (2009). The AMMA-CATCH experiment in the cultivated Sahelian area of south-west Niger: Investigating water cycle response to a fluctuating climate and changing environment. Journal of Hydrology, 375, 34–51.

    CrossRef  Google Scholar 

  • Cherlet et al. (2015). World atlas of desertification (3rd edn.). http://wad.jrc.ec.europa.eu/. Last accessed April 28, 2014.

  • Condit, R., Sukumar, R., Hubbell, S. P., & Foster, R. B. (1998). Predicting population trends from size distributions: A direct test in a tropical tree community. American Naturalist, 152, 495–509.

    CrossRef  Google Scholar 

  • Dardel, C., Kergoat, L., Hiernaux, P., Grippa, M., Mougin, E., Ciais, P., & Nguyen, C.-C. (2014a). Rain-use-efficiency: What it tells us about the conflicting Sahel greening and Sahelian paradox. Remote Sensing, 6, 3446–3474.

    CrossRef  Google Scholar 

  • Dardel, C., Kergoat, L., Hiernaux, P., Mougin, E., Grippa, M., & Tucker, C. J. (2014b). Re-greening Sahel: 30 years of remote sensing data and field observations (Mali, Niger). Remote Sensing of Environment, 140, 350–364.

    CrossRef  Google Scholar 

  • Daw, T. M. (2010). Shifting baselines and memory illusions: What should we worry about when inferring trends from resource user interviews? Animal Conservation, 13, 534–535.

    CrossRef  Google Scholar 

  • Donohue, R. J., Roderick, M. L., McVicar, T. R., & Farquhar, G. D. (2013). Impact of CO2 fertilization on maximum foliage cover across the globe’s warm, arid environments. Geophysical Research Letters, 40, 3031–3035.

    CrossRef  Google Scholar 

  • Eklundh, L., & Olsson, L. (2003). Vegetation index trends for the African Sahel 1982–1999. Geophysical Research Letters, 30: 13-11–13-14.

    Google Scholar 

  • Feely, K. J., Davies, S. J., Noor, N. S., Kassim, A. R., & Tan, S. (2007). Do current stem size distributions predict future population changes? An empirical test of intraspecific patterns in tropical trees at two spatial scales. Journal of Tropical Ecology, 23, 191–198.

    CrossRef  Google Scholar 

  • Fensholt, R., & Proud, S. R. (2012). Evaluation of earth observation based global long term vegetation trends—Comparing GIMMS and MODIS global NDVI time series. Remote Sensing of Environment, 119, 131–147.

    CrossRef  Google Scholar 

  • Fensholt, R., Rasmussen, K., Kaspersen, P., Huber, S., Horion, S., & Swinnen, E. (2013). Assessing land degradation/recovery in the African Sahel from long-term earth observation based primary productivity and precipitation relationships. Remote Sensing, 5, 664–686.

    CrossRef  Google Scholar 

  • Fensholt, R., Rasmussen, K., Nielsen, T. T., & Mbow, C. (2009). Evaluation of earth observation based long term vegetation trends—Intercomparing NDVI time series trend analysis consistency of Sahel from AVHRR GIMMS, Terra MODIS and SPOT VGT data. Remote Sensing of Environment, 113, 1886–1898.

    CrossRef  Google Scholar 

  • Ganaba, S., & Guinko, S. (1995). Etat actuel et dynamique du peuplement ligneux de la région de la Mare d’Oursi (Burkina Faso). Etudes sur la Flore et la Végétation du Burkina Faso et des Pays Avoisinats, 2, 3–14.

    Google Scholar 

  • Gonzalez, P. (1997). Dynamics of biodiversity and human carrying capacity in the Senegal Sahel. PhD dissertation, University of California, Berkeley.

    Google Scholar 

  • Gonzalez, P. (2001). Desertification and a shift of forest species in the West African Sahel. Climate Research, 17, 217–228.

    CrossRef  Google Scholar 

  • Gonzalez, P., Tucker, C. J., & Sy, H. (2012). Tree density and species decline in the African Sahel attributable to climate. Journal of Arid Environments, 78, 55–64.

    CrossRef  Google Scholar 

  • Hall, P., & Bawa, K. (1993). Methods to assess the impact of extraction of nontimber tropical forest products on plant populations. Economical Botany, 47, 234–247.

    CrossRef  Google Scholar 

  • Hanazaki, N., Herbst, D.F., Marques, M.S. & Vandebroek, I. (2013). Evidence of the shifting baseline syndrome in ethnobotanical research. Journal of Ethnobiology and Ethnomedicine, 9.

    Google Scholar 

  • Hansen, M. C., & DeFries, R. S. (2004). Detecting long-term global forest change using continuous fields of tree-cover maps from 8-km advanced very high resolution radiometer (AVHRR) data for the years 1982–99. Ecosystems, 7, 695–716.

    CrossRef  Google Scholar 

  • Harrison, M. N., & Jackson, J. K. (1958). Ecological classification of the vegetation of Sudan. Forests Bulletin 2 and Vegetation Map of Sudan printed by Sudan Survey Department, Khartoum, Topo No. S. 625–40.

    Google Scholar 

  • Hein, L., & De Ridder, N. (2006). Desertification in the Sahel: a reinterpretation. Global Change Biology, 12, 751–758.

    CrossRef  Google Scholar 

  • Hellden, U. (1991). Desertification—time for an assessment? Ambio, 20, 372–383.

    Google Scholar 

  • Herrmann, S. M., Anyamba, A., & Tucker, C. J. (2005). Recent trends in vegetation dynamics in the African Sahel and their relationship to climate. Global Environmental Change, 15, 394–404.

    CrossRef  Google Scholar 

  • Herrmann, S. M., & Hutchinson, C. F. (2005). The changing contexts of the desertification debate. Journal of Arid Environments, 63, 538–555.

    CrossRef  Google Scholar 

  • Herrmann, S. M., Sall, I., & Sy, O. (2014). People and pixels in the Sahel—A study linking coarse-resolution remote sensing observations to land users’ perceptions of their changing environment in Senegal. Ecology and Society (under revision).

    Google Scholar 

  • Herrmann, S. M., & Tappan, G. G. (2013). Vegetation impoverishment despite greening: A case study from central Senegal. Journal of Arid Environments, 90, 55–66.

    CrossRef  Google Scholar 

  • Herrmann, S. M., Wickhorst, A. J., & Marsh, S. E. (2013). Estimation of tree cover in an agricultural parkland of Senegal using rule-based regression tree modeling. Remote Sensing, 5, 4900–4918.

    CrossRef  Google Scholar 

  • Heumann, B. W., Seaquist, J. W., Eklundh, L., & Joensson, P. (2007). AVHRR derived phenological change in the Sahel and Soudan, Africa, 1982–2005. Remote Sensing of Environment, 108, 385–392.

    CrossRef  Google Scholar 

  • Hiernaux, P., & Ayantunde, A. A. (2004). The Fakara: a semi-arid agro-ecosystems under stress. Report of research activities of International Livestock Research Institute (ILRI) in Fakara, South-western Niger, between 1994 and 2002, Desert Margins Program. ICRISAT, Niamey.

    Google Scholar 

  • Hiernaux, P., Diarra, L., Trichon, V., Mougin, E., Soumaguel, N., & Baup, F. (2009a). Woody plant population dynamics in response to climate changes from 1984 to 2006 in Sahel (Gourma, Mali). Journal of Hydrology, 375, 103–113.

    CrossRef  Google Scholar 

  • Hiernaux, P., Mougin, E., Diarra, L., Soumaguel, N., Lavenu, F., Tracol, Y., & Diawara, M. (2009b). Sahelian rangeland response to changes in rainfall over two decades in the Gourma region, Mali. Journal of Hydrology, 375, 114–127.

    CrossRef  Google Scholar 

  • Hiernaux, P., & Turner, M. D. (1996). The effect of clipping on growth and nutrient uptake of Sahelian annual rangelands. Journal of Applied Ecology, 33, 387–399.

    CrossRef  Google Scholar 

  • Huete, A. R., & Jackson, R. D. (1987). Suitability of spectral indices for evaluating vegetation characteristics on arid rangelands. Remote Sensing of Environment, 23, 213–232.

    CrossRef  Google Scholar 

  • Hutchinson, C. F., Herrmann, S. M., Maukonen, T., & Weber, J. (2005). Editorial: Introduction: The “Greening” of the Sahel. Journal of Arid Environments, 63, 535–537.

    CrossRef  Google Scholar 

  • Ibrahim, F. (1978). The problem of desertification in the Republic of the Sudan with spacial reference to Northern Darfur Province. SRC Monograph Series 8.

    Google Scholar 

  • James, M. E., & Kalluri, S. N. V. (1994). The Pathfinder Avhrr land data set—An improved coarse resolution data set for terrestrial monitoring. International Journal of Remote Sensing, 15, 3347–3363.

    CrossRef  Google Scholar 

  • Joint Research Centre of the European Commission. (2015). World atlas of desertification http://wad.jrc.ec.europa.eu/. Last accessed February 7, 2015.

  • Lamprey, H. F. (1988). Report on desert encroachment reconnaissance in Northern Sudan: 21 October to 10 November 1975. Desertification Control Bulletin, 17, 1–7.

    Google Scholar 

  • Lawesson, J. E. (1990). Sahelian woody vegetation in Senegal. Vegetatio, 86, 161–174.

    CrossRef  Google Scholar 

  • Lindskog, P., & Tengberg, A. (1994). Land degradation, natural resources and local knowledge in the Sahel Zone of Burkina Faso. GeoJournal, 33, 365–375.

    Google Scholar 

  • Lykke, A. M. (1998). Assessment of species composition change in savanna vegetation by means of woody plants’ size class distributions and local information. Biodiversity and Conservation, 7, 1261–1275.

    CrossRef  Google Scholar 

  • Lykke, A. M., Fog, B., & Madsen, J. E. (1999). Woody vegetation changes in the Sahel of Burkina Faso assessed by means of local knowledge, aerial photos, and botanical investigations. Geografisk Tidsskrift (Danish Journal of Geography), 57–68.

    Google Scholar 

  • Lykke, A. M., Kristensen, M. K., & Ganaba, S. (2004). Valuation of local use and dynamics of 56 woody species in the Sahel. Biodiversity and Conservation, 13, 1961–1990.

    CrossRef  Google Scholar 

  • Mahamane, L., Iro, D. G., Matig, O. E., & Idrissa, I. A. (2012). Farmer managed tree natural regeneration and diversity in a Sahelian environment: Case study of Maradi region, Niger. Continental Journal of Agricultural Science, 6, 38–49.

    Google Scholar 

  • McCloy, K. R., Los, S., Lucht, W., & Højsgaard, S. A. (2005). A comparative analysis of three long-term NDVI datasets derived from AVHRR satellite data. EARSeL Proceedings, 4, 52–69.

    Google Scholar 

  • Middleton, N., Thomas, D., & United Nations Environmental Programme. (1992). World atlas of desertification (1st edn). London: Arnold.

    Google Scholar 

  • Middleton, N., Thomas, D., & United Nations Environmental Programme. (1997). World atlas of desertification (2nd edn). London: Arnold.

    Google Scholar 

  • Miehe, S., Kluge, J., von Wehrden, H., & Retzer, V. (2010). Long-term degradation of Sahelian rangeland detected by 27 years of field study in Senegal. Journal of Applied Ecology, 47, 692–700.

    CrossRef  Google Scholar 

  • Milich, L., & Weiss, E. (2000). GAC NDVI interannual coefficient of variation (CoV) images: Ground truth sampling of the Sahel along north-south transects. International Journal of Remote Sensing, 21, 235–260.

    CrossRef  Google Scholar 

  • Mortimore, M. (1989). Adapting to drought. Farmers, famine and desertification in West Africa. Cambridge: Cambridge University Press.

    CrossRef  Google Scholar 

  • Mortimore, M., Harris, F. M. A., & Turner, B. (1999). Implications of land use change for the production of plant biomass in densely populated Sahelo-Sudanian shrub-grasslands in north-east Nigeria. Global Ecology and Biogeography, 8, 243–256.

    CrossRef  Google Scholar 

  • Mougin, E., Hiernaux, P., Kergoat, L., Grippa, M., de Rosnay, P., Timouk, F., et al. (2009). The AMMA-CATCH Gourma observatory site in Mali: Relating climatic variations to changes in vegetation, surface hydrology, fluxes and natural resources. Journal of Hydrology, 375, 14–33.

    CrossRef  Google Scholar 

  • National Research Council. (2008). Earth observations from space: The first 50 years of scientific achievements. Washington, D.C.: National Academy Press.

    Google Scholar 

  • Nicholson, S. E. (2013). The West African Sahel: A review of recent studies on the rainfall regime and its interannual variability. ISRN Meteorology, 1–32.

    Google Scholar 

  • Oldeman, L. R., Hakkeling, R. T. A., & Sombroek, W. G. (1991). World map of the status of human-induced soil degradation: An explanatory note, second revised edition. ISRIC/UNEP.

    Google Scholar 

  • Pearce, F. (1992). Mirage of the shifting sands. New Scientist, 136, 38–42.

    Google Scholar 

  • Pinzon, J. E., & Tucker, C. J. (2014). A non-stationary 1981–2012 AVHRR NDVI3 g time series. Remote Sensing, 6, 6929–6960.

    CrossRef  Google Scholar 

  • Poorter, L., Bongers, F., van Rompaey, R. S. A. R., & de Klerk, M. (1996). Regeneration of canopy tree species at five sites in west African moist forest. Forest Ecology and Management, 84, 61–69.

    CrossRef  Google Scholar 

  • Prince, S. (1991a). Satellite remote sensing of primary production: Comparison of results for Sahelian grasslands 1981–1988. International Journal of Remote Sensing, 12, 1301–1311.

    CrossRef  Google Scholar 

  • Prince, S. D. (1991b). A model of regional primary production for use with coarse resolution satellite data. International Journal of Remote Sensing, 12, 1313–1330.

    CrossRef  Google Scholar 

  • Prince, S. D., Brown de Colstoun, E., & Kravitz, L. L. (1998). Evidence from rain-use efficiencies does not indicate extensive Sahelian desertification. Global Change Biology, 4, 359–374.

    CrossRef  Google Scholar 

  • Prince, S. D., Wessels, K. J., Tucker, C. J., & Nicholson, S. E. (2007). Desertification in the Sahel: A reinterpretation of a reinterpretation. Global Change Biology, 13, 1308–1313.

    CrossRef  Google Scholar 

  • Raynaut, C., Gregoire, E., Janin, P., Koechlin, J., & Lavigne Delville, P. (1996). Societies and nature in the Sahel. London: Routledge.

    Google Scholar 

  • Reed, M. S., Dougill, A. J., & Taylor, M. J. (2007). Integrating local and scientific knowledge for adaptation to land degradation: Kalahari rangeland management options. Land Degradation & Development, 18, 249–268.

    CrossRef  Google Scholar 

  • Reij, C., Tappan, G., & Belemvire, A. (2005). Changing land management practices and vegetation on the Central Plateau of Burkina Faso (1968–2002). Journal of Arid Environments, 63, 642–659.

    CrossRef  Google Scholar 

  • Reij, C., Tappan, G., & Smale, M. (2009) Agroenvironmental transformation in the Sahel: Another kind of “Green Revolution”. In: IFPRI Discussion Paper 00914: International Food Policy Research Institute.

    Google Scholar 

  • Reynolds, J. F., & Stafford Smith, D. M. (2002) Do humans cause deserts? Global desertification: Do humans cause deserts? In J. F. Reynolds & D. M. Stafford Smith (Eds.) Berlin: Dahlem University Press.

    Google Scholar 

  • Rouse, J. W., Haas, R. H., Schell, J. A., & Deering, D. W. (1973) Monitoring vegetation systems in the great plains with ERTS. In: Third Earth Resources Technology Satellite-1 Symposium, (Greenbelt: NASA) (pp. 309–317).

    Google Scholar 

  • Schwarz, M., Zimmermann, N. E., & Waser, L. T. (2004). MODIS based continuous fields of tree cover using generalized linear models. IEEE Transactions on Geoscience and Remote Sensing, 4, 2377–2380.

    Google Scholar 

  • Seaquist, J. W., Hickler, T., Eklundh, L., Ardo, J., & Heumann, B. W. (2009). Disentangling the effects of climate and people on Sahel vegetation dynamics. Biogeosciences, 6, 469–477.

    CrossRef  Google Scholar 

  • Shackleton, C. M. (1993). Demography and dynamics of the dominant woodyspecies in a communal and protected area of the eastern Transvaal Lowveld. South African Journal of Botany, 59, 569–574.

    Google Scholar 

  • Sokpon, N., & Biaou, S. H. (2002). The use of diameter distributions in sustained-use management of remnant forests in Benin: case of Bassila forest reserve in North Benin. Forest Ecology and management, 161, 13–25.

    CrossRef  Google Scholar 

  • Sop, T. K., & Oldeland, J. (2013). Local perceptions of woody vegetation dynamics in the context of a ‘greening Sahel’: A case study from Burkina Faso. Land Degradation & Development, 24, 511–527. doi:10.1002/ldr.1144

    Google Scholar 

  • Sop, T. K., Oldeland, J., Bognounou, F., Schmiedel, U., & Thiombiano, A. (2012). Ethnobotanical knowledge and valuation of woody plants species: A comparative analysis of three ethnic groups from the sub-Sahel of Burkina Faso. Environment, Development and Sustainability, 14, 627–649.

    CrossRef  Google Scholar 

  • Sop, T. K., Oldeland, J., Schmiedel, U., Ouedraogo, I., & Thiombiano, A. (2011). Population structure of three woody species in four ethnic domains of the sub-sahel of Burkina Faso. Land Degradation & Development, 22, 519–529.

    CrossRef  Google Scholar 

  • Steven, M. D. (1987). Ground truth—An underview. International Journal of Remote Sensing, 8, 1033–1038.

    CrossRef  Google Scholar 

  • Thomas, D. S. G., & Middleton, N. J. (1994). Desertification. Exploding the myth. Chichester: Wiley.

    Google Scholar 

  • Tougiani, A., Guero, C., & Rinaudo, T. (2009). Success in improving livelihoods through tree crop management and use in Niger. GeoJournal, 74(5), 377–389.

    CrossRef  Google Scholar 

  • Traore, L., Sop, T. K., Dayamba, S. D., Traore, S., Hahn, K., & Thiombiano, A. (2013). Do protected areas really work to conserve species? A case study of three vulnerable woody species in the Sudanian zone of Burkina Faso. Environment, Development and Sustainability, 15, 663–686.

    CrossRef  Google Scholar 

  • Tucker, C. J. (1979). Red and photographic infrared linear combinations for monitoring vegetation. Remote Sensing of Environment, 8, 127–150.

    CrossRef  Google Scholar 

  • Tucker, C.J., Vanpraet, C.L., Sharman, M.J. and van Ittersum, G. (1985). Satellite Remote Sensing of Total Herbaceous Biomass Production in the Senegalese Sahel: 1980–1984. Remote Sensing of Environment, 17, 233–249.

    CrossRef  Google Scholar 

  • Tucker, C. J., Dregne, H. E., & Newcomb, W. W. (1991). Expansion and contraction of the Sahara Desert from 1980 to 1990. Science, 253, 299–301.

    CrossRef  Google Scholar 

  • Tucker, C. J., & Nicholson, S. E. (1999). Variations in the size of the Sahara Desert from 1980 to 1997. Ambio, 28, 587–591.

    Google Scholar 

  • Tucker, C. J., Pinzon, J. E., Brown, M. E., Slayback, D. A., Pak, E. W., Mahoney, R., et al. (2005). An extended AVHRR 8-km NDVI dataset compatible with MODIS and SPOT vegetation NDVI data. International Journal of Remote Sensing, 26, 4485–4498.

    CrossRef  Google Scholar 

  • Tucker, C. J., Vanpraet, C. L., Boerwinkel, E., & Gaston, A. (1983). Satellite remote sensing of total dry matter production in the Senegalese Sahel. Remote Sensing of Environment, 13, 461–474.

    CrossRef  Google Scholar 

  • Venter, S. M., & Witkowski, E. T. F. (2010). Baobab (Adansonia digitata L.) density, size-class distribution and population trends between four land-use types in northern Venda, South Africa. Forest Ecology and Management, 259, 294–300.

    CrossRef  Google Scholar 

  • Warren, A. (2002). Land Degradation is Contextual. Land Degradation and Development, 13, 449–459.

    Google Scholar 

  • Vincke, C., Diedhiou, I., & Grouzis, M. (2010). Long term dynamics and structure of woody vegetation in the Ferlo (Senegal). Journal of Arid Environments, 74, 268–276.

    CrossRef  Google Scholar 

  • Warren, A., & Agnew, C. (1988). An assessment of desertification and land degradation in arid and semi-arid areas. In: International Institute for Environment and Development paper no. 2, (London: Ecology and Conservation Unit, University College).

    Google Scholar 

  • Warren, A., & Olsson, L. (2003). Desertification: Loss of credibility despite the evidence. Annals of Arid Zone, 42, 271–287.

    Google Scholar 

  • Wezel, A. (2005). Decline of woody species in the Sahel. In Huber, B.A., Sinclair, B.J. & Lampe, K.-H. (eds.) African Biodiversity, New York: Springer.

    Google Scholar 

  • Wezel, A., & Haigis, J. (2000). Farmers’ perception of vegetation changes in semi-arid Niger. Land Degradation and Development, 11, 523–534.

    CrossRef  Google Scholar 

  • Wezel, A., & Lykke, A. M. (2006). Woody vegetation change in Sahelian West Africa: Evidence from local knowledge. Environment, Development and Sustainability, 8, 553–567.

    CrossRef  Google Scholar 

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Herrmann, S.M., Sop, T.K. (2016). The Map Is not the Territory: How Satellite Remote Sensing and Ground Evidence Have Re-shaped the Image of Sahelian Desertification. In: Behnke, R., Mortimore, M. (eds) The End of Desertification? . Springer Earth System Sciences. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-642-16014-1_5

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