SYLLA D., Department of Plant Biology, Faculty of Science and Technology, Cheikh Anta Diop University, Cheikh Anta DIOP Avenue, BP 5005, Dakar, Fann, Senegal; Ecological Monitoring Centre for Natural Resource Management, Résidence Fann, Rue Léon Gontran Damas, BP 15532, DAKAR, FANN, SENEGAL

BA T., Ecological Monitoring Centre for Natural Resource Management, Résidence Fann, Rue Léon Gontran Damas, BP 15532, DAKAR, FANN, SENEGAL

SARR O, Ecological Monitoring Centre for Natural Resource Management, Résidence Fann, Rue Léon Gontran Damas, BP 15532, DAKAR, FANN, SENEGAL

SAGNA M. B., Department of Plant Biology, Faculty of Science and Technology, Cheikh Anta Diop University, Cheikh Anta DIOP Avenue, BP 5005, Dakar, Fann, Senegal; Observatoire Hommes-Milieux international (OHMi) Tessékéré, Ferlo, Senegal

SARR M. A., Ecological Monitoring Centre for Natural Resource Management, Résidence Fann, Rue Léon Gontran Damas, BP 15532, DAKAR, FANN, SENEGAL

GUISSE A., Department of Plant Biology, Faculty of Science and Technology, Cheikh Anta Diop University, Cheikh Anta DIOP Avenue, BP 5005, Dakar, Fann, Senegal; Observatoire Hommes-Milieux international (OHMi) Tessékéré, Ferlo, Senegal; UMI 3189 "Environnement, Santé, Sociétés" UGB, UCAD, CNRS, CNRST, USTTB, Dakar, Senegal

Abstract
Aim : This study focuses on the spatio-temporal dynamics of the ecosystems between 1965 to 2017.
Location : sylvopastoral reserve of the six Ferlo boreholes in Senegal
Methods : The methodological approach consists in delineating and mapping land cover in the reserve, in 1965 and 2017 and, analyzing changes during this period using remote sensing techniques and Geographic Information Systems (GIS).
Results : The results obtained show the identification of 10 land-use patterns in the reserve for the year 2017: savannah woodland, shrub savannah with tree, shrub savannah, shrub steppe with tree, shrub steppe, vegetable crop rainfall, village, pond, bare soil, tree plantation. In addition to savannah with tree, all these classes are present in 1965, except for the "tree plantation" class. The zones of shrub savannah and shrub steppe and shrub steppe with tree gradually changed between these dates, while the zones of shrub savannah with tree decreased. The areas occupied by savannah with tree disappeared completely. Analysis of changes between 1965 and 2017 showed that 19.71% of the reserve area remained in its original state, 70.58% was modified and 9.71% was converted.
Main conclusion : This study has been widened to the whole “sylvopastoral reserve” protected area, which will make possible to evaluate the effectiveness of the management plans for protected areas in the Ferlo.

Keywords
Dynamics, Ecosystem, Ferlo, GIS, Land cover, Senegal, Remote sensing

Cite this paper
SYLLA D., BA T., SARR O, SAGNA M. B., SARR M. A., GUISSE A., Spatio-temporal dynamics of the ecosystems of the Six Forages sylvopastoral reserve (Ferlo, North-Senegal) , SCIREA Journal of Geosciences. Volume 4, Issue 2, April 2020 | PP. 50-75.

References

[ 1 ]	SSO. Sahel and Sahara Observatory. 2018. Sahel and West Africa - atlas of land use maps. Building Resilience through Innovation, Communication and Knowledge Services Project - BRICKS. 204 p. http://www.oss-online.org/sites/default/files/publications/OSS-BRICKS-Atlas_En.pdf
[ 2 ]	EMC. Ecology Monitoring Centre. 2003. Land Degradation Assessment in Senegal: FAO Project. Land Degradation Assessment (LADA). Preliminary report. 59 p. http://www.fao.org/tempref/agl/agll/ladadocs/RapportLADASenegal.doc
[ 3 ]	SNAPS Senegal's national protected areas strategy. 2011. Report from the Water and Forestry Directorate. 42 p. http://extwprlegs1.fao.org/docs/pdf/sen160732.pdf
[ 4 ]	Tansley, G. A. 1935. The Use and abuse of vegetational concepts and terms. Ecology, vol. XVI, no 3. 284-307 p. https://www.researchgate.net/publication/249823757_Tansley_AG_1935_The_use_and_abuse_of_vegetational_concepts_and_terms_Ecology_16_284_307
[ 5 ]	Sylla, D., Ba, T., et Guisse, A. 2019. Mapping changes in vegetation cover in the protected areas of Ferlo (Northern Senegal): the case of the biosphere reserve. Physio-Géo [Online], Volume 13 \| 2019. 115-132. http://journals.openedition.org/physio-geo/8178
[ 6 ]	Ba, T., Akpo L.E., Diouf, A.A. 2017. Spatial and temporal dynamics of ecosystems in the Ferlo watershed. Journal of Animal and Plant Sciences, 2017. Vol.33, Issue 1. 5255-5273 p. http://m.elewa.org/Journals/wp-content/uploads/2017/06/3.Taibou-3.pdf
[ 7 ]	Diouf. M., Logbo. J., DO. F, C., Akpo. L, E. 2013. Determinism of the foliage of Acacia tortilis (Forsk.) in the sylvopastoral reserve of Sogobé, Ferlo, North-Senegal. International Journal Biology and Chemical Science 7(5). 2106-2116 p. https://www.ajol.info//index.php/ijbcs/article/view/102182
[ 8 ]	Diouf, J. C. 2011. Dynamics of woody settlement in Ferlo (North Senegal), consequences and prospects for sustainable management. PhD thesis in plant biology: option Ecology, UCAD. 264 p. https://www.ppzs.org/FichiersComplementaires/Th%C3%A8se-Joseph-C-Diouf.pdf
[ 9 ]	Bakhoum, A. 2013. Dynamics of fodder resources: indicators of resilience of community rangelands in Tessékéré au Ferlo, (Northern Senegal). PhD: Biology, pathology and animal production: option: Pastoralism, UCAD. 118 p. https://afrique-ouest.cirad.fr/publications-et-ressources/theses-memoires/annees-anterieures/dynamiques-des-ressources-furrageres-indicateur-de-resilience-des-parcours-communautaires-de-tessekere-au-ferlo-nord-senegal
[ 10 ]	Ndiaye, O., Diallo, A., Wood, S A., Guisse A. 2014. Structural Diversity of Woody Species in the Senegalese Semi-Arid Zone-Ferlo. American Journal of Plant Sciences, Vol 5. 416-426 p. http://www.columbia.edu/~saw2177/pubs/Ndiaye%20et%20al%20(Am%20J%20Plant%20Sci%202014).pdf
[ 11 ]	Sarr, M A. 2009 (b). Recent evolution of climate and vegetation in Senegal (case of Ferlo). PhD thesis, Université Jean Moulin, Lyon3, LCRE UMR 5600 CNRS. 410 p. http://www.theses.fr/2009LYO31058
[ 12 ]	Cissé, S., Eymard, L., Ottlé, C., Ndione, J.A., Gaye, A.T., Pinsard, F. 2016. Precipitation Intra-seasonal variability and vegetation growth in the Ferlo Basin (Senegal). Remote Sensing, 8. 66 p. https://doi.org/10.3390/rs8010066
[ 13 ]	Ancey, V., Wane, A., Müller, A., André, D. and Leclerc, G. 2008. Paying the Ferlo for Water Pastoral Strategies for Community Water Management. Autrepart, 46(2). 51-66. https://doi.org/10.3917/autr.046.0051
[ 14 ]	Diop, A.T., Diaw, O.T., Diémé, I., Touré, T., Sy, O, Diémé, G. 2004. Ponds in the area sylvopastoral of Senegal: evolutionary trends and role in production strategies pastoral people. Journal Breeding Veterinary Medicine Tropical countries 57 (1-2). 77-85 https://agritrop.cirad.fr/524015/1/ID524015.pdf
[ 15 ]	Sy, O. 2009. Role of the waterhole in the management of the Sahelian pastoral systems of Ferlo (Senegal). Cybergeo: European Journal of Geography, Environment, Nature, Landscape, document 440. URL: http://journals.openedition.org/cybergeo/22057.
[ 16 ]	Sarr, M A. 2009 (a). Mapping of land use changes between 1990 and 2002 in northern Senegal (Ferlo) using Landsat images. Cybergeo: European Journal of Geography, Environment, Nature, Landscape, document 472. url: http://cybergeo.revues.org/22707.
[ 17 ]	Sarr, M A., Gachonb, P., Seidou, O., Bryant, C.R., Ndione, J.A., et Comby, J. 2015. Inconsistent linear trends in Senegalese rainfall indices from 1950 to 2007. Hydrological Sciences Journal. Volume 60 n°9. 1-12 p. https://www.tandfonline.com/doi/full/10.1080/02626667.2014.926364
[ 18 ]	Dardel, C. 2015. Chapter 6. Between desertification and regreening of the Sahel: What is really happening? In: is really happening? In: Rural Societies and Climate Change environmental issues in West Africa [online]. Marseille : IRD Éditions. https://books.openedition.org/irdeditions/12340
[ 19 ]	Adey, S.A., Abdenbi, Z.E.A., Mahamat, A.M., Abdoulaye, M.O., Rabea, Z., Najiba, B., Saïd, L., et Najib, G. 2018. Analysis of the evolution of forest and pre-forest plant formations in the Sahel: the case of the Ouaddaï and Wadi-Fira regions in Chad. Physio-Géo, Volume 12 \| -1 : 79-103 p. https://journals.openedition.org/physio-geo/5882
[ 20 ]	Wane, A., Ancey V., Grosdidier B. 2006. The pastoral units of the Senegalese Sahel, tools for the management of livestock and pastoral spaces. Sustainable development and territories, dossier 8. URL: http://journals.openedition.org/developpementdurable/3292.
[ 21 ]	Ndong, A.T., Ndiaye, O., Faye, M.N., Galop, D., Guissé. A. 2015. Woody species of Ferlo-Nord, Senegal: current status and use. Overseas Notebooks 271. 401-422. https://journals.openedition.org/com/7557
[ 22 ]	Roberty G. 1952. The vegetation of the Ferlo. Extract from the Bulletin of the French Institute of Black Africa. Volume XlV, No. 3. 777-798 p. https://horizon.documentation.ird.fr/exl-doc/pleins_textes/pleins_textes_6/b_fdi_39-40/43297.pdf
[ 23 ]	Fall, A. 2017. From Ferlo to the Groundnut Basin (Senegal): analysis of the floristic composition of the vegetation considered as a resource and as an indicator of socio-environmental changes. Physio-Géo, 11(1), 65-91 p. https://journals.openedition.org/physio-geo/5265
[ 24 ]	Girard, M. C 1995. Visual interpretation of satellite images for spatial soil analysis: an example from the lodève region. Soil survey and management 2-1. 7-24 p. http://www.afes.fr/wp-content/uploads/2017/10/EGS_2_1_GIRARD.pdf
[ 25 ]	Major, D.J., Baret, F., Guyot, J. 1990. A ratio vegetation index adjusted for soil brightness. International Journal of Remote Sensing, vol n° 5. DOI: 10.1080/01431169008955053. 727-740 p.
[ 26 ]	Aubreville, A. 1957. Yangambi Agreement on the Nomenclature of African Types of Vegetation. Bois et Forêts des Tropiques, n°51, Janvier-Février. 23-27 p. http://bft.cirad.fr/cd/BFT_051_23-27.pdf
[ 27 ]	Dendoncker, M., Ngom, D., et Vincke, C. 2015. Tree dynamics (1955-2012) and their uses in Senegal’s Ferlo’s région: insight from a historical vegetation database, local knowledge and field inventories. Bois et Forêts des tropiques, N° 326 (4). 25-41 p. https://www.researchgate.net/publication/294873014_Trees_dynamics_1955-2012_and_their_uses_in_the_Senegal%27s_Ferlo_region_insights_from_a_historical_vegetation_database_local_knowledge_and_field_inventories
[ 28 ]	Hountoundji, Y.C., Nicolas, J., Sokpon, N., Ozer, P. 2005. Demonstrating the resilience of Sahelian vegetation by low-resolution remote sensing in Niger following drought episodes. Belgeo, 4, 499-516 p. https://journals.openedition.org/belgeo/12245
[ 29 ]	Inoussa, M.M., Mahamane, A., Mbow, C., Bachmann Y. 2011. Spatial and Temporal Dynamics of Open Forests in the W National Park of Niger West Africa). Science and Planetary Changes - Drought Volume 22, Number 2. 108-116 p.. 108-116 p. https://www.jle.com/fr/revues/sec/edocs/dynamique_spatio_temporelle_des_forets_claires_dans_le_parc_national_du_w_du_niger_afrique_de_louest__288976/article.phtml
[ 30 ]	Ouaba, A.P 2013. Climate change, vegetation dynamics and peasant perception in the Burkinabe Sahel. Single doctoral thesis in geography: Doctoral School of Letters, Human Sciences and Communications, Ouagadougou University. 305 p. http://hydrologie.org/THE/OUOBA_AP.pdf
[ 31 ]	Touré, A.A., Guillon, R., Garba, Z., Rajot, J.L., Petit, C., Bichet, V., Durand, A., et Sebag, D. 2010. Evolution of the Sahelian landscapes over the last six decades in the Niamey region: from the disappearance of the tiger bush to the surface crusting of the soil. Géoscience et développement volume spécial impacts de l'homme et du climat sur les milieux sahéliens N° 47-48. 35-40 p. https://hal-insu.archives-ouvertes.fr/insu-00956999/document
[ 32 ]	Ouaba, P., Da Dapola, E., et Paré, S. 2014. Local perception of the dynamics of woodland settlement over the last twenty years in the Burkinabe Sahel. Vertigo volume 14, number 2, September 2014.14(2). 13 p. https://journals.openedition.org/vertigo/15131
[ 33 ]	Poulet, A. R. 1974. Ecological research on a northern Ferlo Sahelian savannah, Senegal: some effects of drought on mammalian settlement. Earth and life journal of Applied Ecology, vo1.1. 124-130 p.
[ 34 ]	Barral, H. 1982. Le Ferlo des forages: old and current management of the space. ORSTOM. 85 p. https://horizon.documentation.ird.fr/exl-doc/pleins_textes/divers15-06/010004749.pdf
[ 35 ]	Wezel, A. 2004. Local knowledge of vegetation changes in Sahelian Africa-implications for local resource management. In The Sahel Current politics in West Africa,the use of local knowledge in applied research-Participation in project planning and capacity building. Serein occasional paper 37-52 p. https://www.researchgate.net/publication/235660092_THE_SAHEL_Current_politics_in_West_Africa_The_use_of_local_knowledge_in_applied_research_Participation_in_project_planning_and_capacity_building
[ 36 ]	Taugourdeau, S., Diouf, A., Mbaye, T., Dendoncker, M., Ndiaye, O., Hiernaux, P., Juanes, X., et Ickowitz, A. 2017. Ecological factors impacting woody and herbaceous plant communities in the Ferlo rangelands between 1970 and 1981. Pastoralism in the Current of Global Changes: Challenges, Issues, Perspectives (Dakar, Senegal, 20/11/2017 to 24/11/2017). In: Book of abstracts, 59-60 p. https://agritrop.cirad.fr/586083/1/166905_Taugourdeauetalp2cg2017.pdf
[ 37 ]	Fecherolle, D. 2016. Characterization of natural woody regeneration in the Ferlo (Senegal). Dissertation of bio-engineer, Faculty of Bio-engineering, Catholic University of Leuven. 158. https://hal.archives-ouvertes.fr/hal-01326067/document
[ 38 ]	Ngom, D., Fall, T., Sarr, O., Diatta, S., Akpo, L.E., 2013. Ecological characteristics of the woody stand of the Ferlo biosphere reserve (North Senegal). Journal of Applied Biosciences 65. 5008 – 5023p. https://www.ajol.info//index.php/jab/article/view/89644
[ 39 ]	Ndiaye, M., Ndione., M.E., et Akpo, L E. 2010. Characteristics of woody plants in the pastoral terroirs of Ranérou. Journal des Sciences. 10 (3), 12–27 p. http://www.cadjds.org/assets/upload/media1/JDSV10N3/Article%20M.%20Ndiaye%20et%20al.pdf
[ 40 ]	Ndong, A. 2016. Study of the history and the state of the vegetation of the Ferlo in the North of Senegal. PhD thesis, specialization Ecology and agroforestry, UCAD, Dakar. 161 p. https://bibnum.ucad.sn/viewer.php?c=ths&d=ths%5f2017%5f0034
[ 41 ]	Ninot, O. 2008. Livestock and territory in the "Ferlo", a pastoral zone in northern Senegal. Mission report 22 November - 1 December 2007. 48 p. http://epe.cirad.fr/fr2/icare/docs/R_Mission_Senegal_Ferlo_22_11_01_12_07.pdf
[ 42 ]	Santoir, C. 1994. Decadence and Resistance of Pastoralism The Fulani of the Senegal River Valley. Cahiers d'études africaines 133-135 XXXIV-1. 231-263 p. https://horizon.documentation.ird.fr/exldoc/pleins_textes/pleins_textes_5/pt5/travaux_d/16611.pdf
[ 43 ]	Sy, O. 2010. Pastoral mobility in the Lower Ferlo Valley in the context of water resettlement. The Overseas Notebooks 249. 31-46 p. https://journals.openedition.org/com/5848