Genin, Didier

Hanafi, Ali

English

University of Kentucky

University of Kentucky UKnowledge International Grassland Congress Proceedings 21st International Grassland Congress / 8th International Rangeland Congress Estimating Pastoral Pressure on Arid Rangelands Taking into Account Herd Management Practices Didier Genin Université de Provence, France Ali Hanafi Université de Tunis, Tunisia Follow this and additional works at: https://uknowledge.uky.edu/igc  Part of the Plant Sciences Commons, and the Soil Science Commons This document is available at https://uknowledge.uky.edu/igc/21/4-1/16 The 21st International Grassland Congress / 8th International Rangeland Congress took place in Hohhot, China from June 29 through July 5, 2008. Proceedings edited by Organizing Committee of 2008 IGC/IRC Conference Published by Guangdong People's Publishing House This Event is brought to you for free and open access by the Plant and Soil Sciences at UKnowledge. It has been accepted for inclusion in International Grassland Congress Proceedings by an authorized administrator of UKnowledge. For more information, please contact UKnowledge@lsv.uky.edu. 瞯 ]574　 瞯 　 Multifunctional Grasslands in a Changing World 　 Volume Ⅰ 　Grasslands/Rangelands Resources and Ecology ——— Indicators for Sustainable Use and Conservation of Grasslands/Rangelands ResourcesEstimating pastoral pressure on arid rangelands taking into account herd management practicesDidier GEN IN 1 , A li HA NA FI 21 IRD , L aboratoire Population , Env ironnement , Dévelop pement , UMR 151 , Université de Provence , Centre St‐Charles , 3Place V . H ugo , 13331 Marseille cedex 3 , France , E‐mail : didier .genin ＠ up .univ － mrs . f r ; 2 Université de Tunis ,L aboratoire de biogéographie , Tunis , TunisieKey words : pastoral pressure , arid rangelands , herd management , TunisiaIntroduction One of the main critics formulated against the grazing pressure concept , is that proposed indexes usually do notinclude elements of livestock management ( i .e . forage schedules , temporality of herd movements , supplemental feeding ) .However , these elements largely modulate the actual level of pressure livestock can exercise on rangeland integrity .Materials and methods Study area was located in the arid region of Jeffara ( South East Tunisia) , with mean annual rainfalls ofabout １７０ mm . One hundred parcels of Rhanterium suaveolens and Stip a tenacissima steppes were surveyed ( plant covermeasurements , floristic diversity , plant types) in order to characterise range conditions . At the same time , qualitative surveyswere performed on each parcel with pastoralists regarding their herd and pastoral management ( type of livestock grazingmanagement ( transhumant or sedentary ) , types and temporality of uses , tenure system , livestock feeding system , seasonal anddaily grazing patterns , types and levels of complementation , etc .) . Collected data were processed by means of MultipleFactorial correspondences analyses , and constituted the basis for the formulation of a Pastoral Use Intensity Index ( IIUP) , asfollow :IIUP ＝ NA .NMU .TU .PPA .PRPSP . １２Where : NA : number of small stock ( in Ovine Units) ; NMU : Numbers of months where rangeland is grazed during the year ;TU : qualitative variable related to the intensity of use during grazing period ( continuous grazing ＝ １ , diffuse grazing onrangeland integrated in larger grazing patterns ＝ ０ .５ ) ; PPA : proportion of grazed forages in the diet of small stock (０％ ＝ ０ ; ０‐２０％ ＝ ０畅１ ; ２０‐５０％ ＝ ０畅３ ; ５０‐９０％ ＝ ０畅７ ; ＞ ９０％ ＝ １ ) ; PRP : eventual period of resting of the parcel during spring ( Ifrangeland is not grazed during spring then PRP ＝ ０ .５ , if not PRP ＝ １) ; SUP : surface of rangeland in hectares ; １２ correspondsto the twelve months of the year .This index was related to the classical calculation of stocking rate and to the range conditions of the １００ studied parcels .Results and discussion IIUP ranged from ０ to ６５ , while instantaneous stocking rate varied from ０ to １３２ . The latter index led toan over‐estimated evaluation of grazing pressure because it did not integrate eventual adjustments made by herders in order tobalance herd requirements and forage resources of rangelands . We found a clear relationship between IIUP value and rangecondition . In R . suaveolens steppes about ５０％ of rangelands with a low or moderate IIUP were classified in good condition ,while only ２６％ of them with high IIUP was found in good condition . This relationship was still stronger in S . tenacissimasteppes . Relationships between stocking rate and IIUP values indicate the magnitude of the risk of overestimating grazingpressure ( slopes of the regression curves between ０ .３５ and ０ .４５ ) .Conclusions The IIUP index , potentially , appears to be a useful tool for evaluating livestock management impacts onrangelands , thanks to its capacity to take into account several aspects of herds management practices which fully influencegrazing pressure level . However , it needs to be refined in order to simplify it , and be tested within different rangelandsituations in order to evaluate its heuristic character .ReferencesBenhke R . , Scoones I . , Kerven K . ( Eds) , (１９９３) . Range ecology at disequilibrium . London , ODI , ２４８ p .Genin D . , Guillaume H . , Ouessar M . , et al . ( Eds) , ( ２００６ ) . Entre désertification et développement ,la Jeffara tunisienne .Tunis , IRD‐IRA‐Cérès Editions , ３５１ p .Hanafi A . , ( ２００８ ) . Steppes et systèmes de production dans la Jeffara tunisienne ,recherche sur les relations dynamiques .Thèse Doct . ,FSH ,Univ . Tunis ,Tunis , ３７１ p .Roe E . , (１９９７) . Viewpoint : On rangeland carrying capacity . J . Range Manage . , ５０(５) : ４６７‐４７２ .

Estimating Pastoral Pressure on Arid Rangelands Taking into Account Herd Management Practices

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Estimating Pastoral Pressure on Arid Rangelands Taking into Account Herd Management Practices

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