Grazing effects on vegetation dynamics in the savannah ecosystems of the Sahel  

作　　者：Haftay Hailu Gebremedhn Ousmane Ndiaye Sylvanus Mensah Cofélas Fassinou Simon Taugourdeau Torbern Tagesson Paulo Salgado 

机构地区：[1]African Center of Excellence for Climate-Smart Agriculture and Biodiversity Conservation,Haramaya University,P.O.Box 138,Dire Dawa,Ethiopia [2]Dispositif en Partenariat«Pôle Pastoralisme Et Zones Sèches»,Route du Front de Terre BP 2057,Pôle de Recherche de Hann,ISRA,Dakar,Senegal [3]Centre de Recherches Zootechniques de Dahra,Institut Sénégalais de Recherches Agricoles,Dakar,Senegal [4]Laboratoire de Biomathématiques et d’Estimations Forestières,Facultédes Sciences Agronomiques,Universitéd’Abomey-Calavi,Cotonou,Benin [5]Chair of Forest Growth and Dendroecology,Albert-Ludwigs-Universität Freiburg,Freiburg Im Breisgau,Germany [6]Facultédes Sciences et Techniques,Département BV,UniversitéCheikh-Anta-Diop,Dakar,Senegal [7]UMR SELMET,CIRAD,INRAE,Institut Agro Univ Montpellier,Montpellier,France [8]Department of Physical Geography and Ecosystem Science,Lund University,Sölvegatan 12,22362 Lund,Sweden [9]Department of Geosciences and Natural Resource Management,University of Copenhagen,Øster Voldgade 10,1350 Copenhagen,Denmark

出　　处：《Ecological Processes》2023年第1期752-763,共12页生态过程（英文）

基　　金：funded by the New Zealand Government to support the objectives of the Global Research Alliance on Agricultural Greenhouse Gases;the CaSSECS project(Carbon Sequestration and Green-house Gas Emissions in(Agro)Sylvopastoral Ecosystems in the Sahelian CILSS States)[FOOD/2019/410-169];Tagesson was additionally funded by the Swedish National Space Agency(SNSA 2021-00144;2021-00111)and FORMAS(Dnr.2021-00644).

摘　　要：Background The savannah ecosystems of Sahel have experienced continuous and heavy grazing of livestock for centuries but still,their vegetation response to grazing pressure remains poorly understood.In this study,we analysed the herbaceous plant dynamics,measured by species diversity,composition,cover,and biomass in response to grazing pressure in the savannah ecosystems of Sahel.In Senegal,we selected four savannah sites represented with high,moderate,light and no grazing intensity levels.Transect survey methods were used for sampling the vegetation data within each of the sites.Species richness and composition were analysed using species accumulation curve and multivariate analyses.Furthermore,we used General Linear Models and a piecewise Structural Equation Model(pSEM)to examine the relationships between grazing intensity,vegetation cover,diversity and biomass.Results The herbaceous species diversity and composition varied significantly among the different grazing intensity levels(p<0.001).The plant species composition shifted from the dominance of grass cover to the dominance of forb cover with increasing grazing pressure.Moreover,the attributes of species diversity,herbaceous biomass,and ground cover were higher on sites with low grazing than sites with high and moderate grazing intensity.Across all sites,species diversity was positively related to total biomass.The pSEM explained 37%of the variance in total biomass and revealed that grazing intensity negatively influenced total biomass both directly and indirectly through its negative influence on species diversity.Conclusions Managing grazing intensity may lead to higher plant production and higher mixed forage establishment in the dryland savannah ecosystems.This information can be used to support land management strategies and promote sustainable grazing practices that balance the needs of livestock with the conservation of ecosystem health and biodiversity.

关 键 词：Biomass BIODIVERSITY Diodella sarmentosa FORB Grazing intensity Invasive species Pastoral ecosystem Senegal West Africa 

分 类 号：S812[农业科学—草业科学] X171.1[农业科学—畜牧学]