Balancing development and conservation in Saharan Tunisia

8/13/2019 Balancing development and conservation in Saharan Tunisia

1/8

Balancing Developmentand Conservation inPre-Saharan TunisiaBY GEORGES NOVIKOFF AND MOHAMED SKOURIIn the immediate hinterland of the Sahara desert increasing human andanimal populations combined wi th increasingly intensive agriculture haveled to desertification of once-fertile grazing lands. The authors suggest ways toprevent the further spread of the desert.

Tunisia is located at the northeastern edgeof Africa, bordered by Algeria, Libya, andthe Mediterranean Sea. Its Mediterraneanclimate brings high summer temperatures,with daily variations increasing with dis-tance from the sea. Precipitation occurs inautumn, winter and spring.The Atlas Mountains, which extendthrough North Africa, divide Tunisia intotwo quite different climatic zones. In thenorth, precipitation varies from 1500 mmto 350 mm annually. In the central andsouthern regions which occupy 80 percentof Tunisias 15.5million hectares, precipi-tation varies from 350 mm to less than 100mm.Central and southern Tunisia wereformerly grazing areas, traditionally ex-ploited by nomadic pastoralists. Summerdroughts limit Tunisias forage resources,and the forage utilization and animal pro-duction were at one time regulated ac-cording to climatic fluctuations. Over-grazing was always a problem, particu-larly in the south, but it was corrected byflock reductions due to droughts and bymovement of flocks from place to place insearch of green pastures.However, since the beginning of thiscentury the population has become lessnomadic. The land cultivated for cerealand tree crops olives, almonds) has pro-gressively increased, resulting in reducedgrazing land. Similarly as the humanpopulation rose, so too have the sheepand goat populations,, exerting furtherpressure. The introduction of disc plough-ing during the last 25 years has acceler-ated erosion of thin soils. The combina-tion of human and livestock populationAMBIO, 1981

disc harrowing culti vation n Tunisia. The introduction of disc harro-wing during the last25 years has acceleratedsoil erosion.

b


2/8

Figure 1. Principal study areas of the different projects in pre-Saharan Tunisia.

I DE DJE RB A

Location of major project sites7 Garaet Zougrata

03:US/IBP Desert B iomeNative vegetationCoastal Area an d Sal ine So i ls

Cult ivated sal ine soi lsFrui t treeso 25.000 oliv e trees. 5.000 indiv idua ls of dif ferent fruit-treesPalmsXerothermic regime amou nt o f days b io log ica l ly dry)

Steppe with rocky h i l lsS teppe wi t h loamy so i lsAl fa St ipa tenaciss ima) s teppe w i th l ight so i ls

Med iterranean zone A A A F r om 2 5 0 t o 3 0 0ow sh rubs ga r r igue) A A A F r o m 2 0 0 t o 2 5 0

Introduced or modified vegetation A A A From 150 to 200Crops From the internat ional m ap of vegetat ion Tunis-SfaxA. Vernet and H. E. Gaussen with M Gounot, N. Le Houero u,A. Schoenenberger, A. Thiault, M Novikoff)Crop w i thou t fa l lowDiscont inuous c ropping systemOasis

Vegetable gardens

136 AMBIO VOL 10 NO 2-3


3/8

increases, a shrinking land base, andagricultural expansion and mechanizationhas led to a serious problem of degrada-tion and even desertification of Tunisiasformer grazing lands.In 1969 the Tunisia Ministry ofAgriculture began a detailed study of pre-Saharan environments, in an effort to re-store some ecological balance betweenagriculture, production and basic resourceutilization. Two major projects were un-dertaken, a Research and DevelopmentProject for Rangelands in SouthernCentral Tunisia joint project UNDPlFAO/UNESCO), and a Desert Biome Projectunder the International Biological Pro-gram IBP).The aims of the projects are to improvethe knowledge of the functioning of desertfringe ecosystems and to identify andformulate management methods thatwould ensure rational multiple land usefor Tunisian rangelands. In addition theprojects provide an approach to obtainingenvironmental information on desert trig-gering mechanisms, and a natural re-sources survey.With the creation of the UNESCO Manand the Biosphere Program, followed byan expression of interest from Tunisia,both studies were incorporated into theMAB research activity on grazing landsand arid and semi-arid ecosystems. Assuch they represent one example ofMABs efforts to apply ecological re-search to critical environmental and de-velopment problems.SUMMARY RESEARCH RESULTSAND DISCUSSIONMost of the research is concentrated inthe coastal region of southern TunisiaFigure 1). The area includes the oases ofGabes and Zarzis and the towns of Mede-nin, Mareth, and Ben Gardan. Vegetationis a sparse and shrubby steppe. Annualrainfall ranges from 180-200 mm on thecoast to 100-120 mm inland, typical forthe pre-Saharan areas of Africa.

Research has been conducted on fourmain themes: primary productivity as abasis for range management planning;range management studies of effects ofgrazing practices on vegetation and soil;desertification and ways to combat it; andthe preparation of management proposalstaking account of ecological and socio-economic factors .Primary productivityThe studies on primary productivity at-tempted to understand the functioning ofpre-desertic ecosystems a t Oglat Merteba,Zougrata, and Bir Lahmar, and identifiedthe factors which affect the primary pro-ductivity of rangelands in these sites.Data was gathered n productivity inrelation to different climatic, soil, and hu-man factors (1). It was found that the totalprecipitation and its seasonal distribution

strongly affected primary productivity,and that an even distribution of rainthroughout the year is much more favora-ble to the development of vegetation thana seasonal one. Furthermore droughts,occurring mostly in the late fall and earlywinter, are very detrimental to vegetationgrowth.In addition to confirming alreadyknown results, this research provides use-ful quantitative data for precisely de-scribed environments. It also shows theeffect of rainfall and temperature onphysical and chemical features of the soil.For example, it was shown that below arelatively low threshold of precipitation200-250 mm per year), a sharp decreasein vegetation productivity occurs, indicat-ing a very low soil trophic level.The results of the studies were used toprepare range maps showing the majorrange units and other features, such asannual and seasonal primary productivityand optimal period of use, which are use-ful for rational land use planning. Suchplans were worked out for Oglat Merteba100 O00 ha), Zougrata (80 O00 ha) and BirLahmar 10000 ha), and several othersmaller areas for the purpose of demon-stration and extension. Methods for in-creasing animal production were im-proved through various forage and animalhusbandry experiments. For the Zougrataarea, simulation models were worked topredict trends in productivity 2).Range management studiesExtensive studies were carried out onways of improving livestock managementand of stimulating the regeneration of theplant cover. For example, under the Des-ert Biome Project a study was done of thearfej Rhanterium suaveolen s) steppe, the

plant formation which is the most vulnera-ble to erosion and the most characteristicof the area.Two experimental stations, Dar ez Za-oui and Henchir Essian, were also estab-lished and meteorological recordings weremade during seven years. Annual precipi-tation varied from 16.5 mm to 490 mm andtwo years out of seven, the rainfall wasbelow 70 mm-the amount which definesthe beginning of a drought.Studies were carried out on plots withsimilar vegetation types, each plot beingused during a different season. Each year,sheep and goats grazed in the same sea-sonal order on each plot. Results areshown in Table 1 for one year 1976-77).The precipitation was 68 mm, only halfthe yearly average 3). Some plant groups,such as the highly preferred small peren-nial species, were consumed primarilyduring the summer drought and less dur-ing the other seasons.The groups of plants requiring onlysmall amounts of precipitation 20-30 mm)to grow in winter provided the most im-portant part of the diet of ewes during thecritical lambing period. This was the casefor biannual plant species in the winterplot. Another group of species, whichmay be called the forage reserve compo-nent of the range, is consumed in largequantities only after the other plantgroups have been exhausted. In this studythis was the case of shrubs at the end ofthe winter grazing period. Annual species

were poorly represented in the animalsdiet: due to low precipitation, few annualsgrew, and those that did were quite small.During a year when precipitation wascloser to the average such as the 154 mmbetween September 1977 and summer1978), annual species represented 50 per-

Table 1. Consumption of plant species groups i n plots grazed during d ifferent seasons

Beginning o f rainfallSummer Autumn Winter SpringPlant species groups Beginning End ofof season season Beginning End of Beginningof season season of season

Percentof diet by weightLitterAnnualspeciesSmallperennialspeciesShrubsBiannualspeciesPerennialgrasses

SheepGoatsSheepGoatsSheepGoatsSheepGoatsSheepGoatsSheepGoats

12 9 89 8 74 3 0 12 6 60 6 42 9 O0 4 O 0 5 0 61 1 , O 0 4 0.3

69 5 2 0 5 3 14 787 1 4 2 7 4 19 9

4 6 7 8 12 2 7 84.5 34 9 45 4 17 312 2 O 6 9 72 64 7 O 1o 62 10 4 0 4 0 8 0 20.1 0 2 2 9 0 4

1 7 2 3O O7 1 15 20 4 5 2

11 8 21 110 6 20 8

67 9 20 984 0 42 910 6 40 50 9 31 00 9 O4 1 0 1

AMBIO, 1981 137


4/8

cent of the total productivity, and theirsize was taller than 10 cm. Annuals werehighly preferred in winter and spring,ranking ahead of the biannual species.The forage reserve component was con-sumed mostly at the end of spring andsummer.It can be concluded, therefore, that toensure optimal nutrition of the flock withminimum supplementary feeding, a pre-Saharan pasture should contain largeamounts of each of the above plantgroups. These species need to be de-veloped either through adequate grazingtreatments, or by reseeding the poorestranges 4).Studies of mixed flocks, half of sheepand half of goats, showed that goats insuch a flock consumed much more of thetallest vegetation group shrubs) than aflock of goats alone. Sheep consumelarger amounts of the annual and biannualspecies when in a mixed flock than in all-sheep flocks. From a practical standpoint,this suggests that the goat is not the nuis-ance animal that it is generally consideredto be. Man himself, by associating goatswith sheep, has made grazing by goatsmore destructive. Similar results havebeen found in South America (5).The consumption of litter has seriousconsequences for the protection of fragilesoils against wind erosion (6). When rainsare delayed, sheep and goats, finding nonew forage resources, consume largeamounts of litter. Excessive loss of litterexposes the soil to trampling, looseningthe soil particles which are then carriedaway by wind. The threshold amount oflitter was measured in the plots; it wasfound to vary with the vegetation com-position of the range. In terms of thequantity of litter consumption, it is in-teresting to note that sheep contributemore to desertification than goats.Studies of grazing treatments showedan increase of 22 percent in total pro-ductivity for spring deferred grazing, ascompared to continuous year-long grazingTable 2). Furthermore, there was betterproductivity from desired species compo-nents: an increase from shrubs, which areconsumable in summer, and an increasefrom annual plant species, which takequick advantage of available rain.During a year of rainfall (150 mm), theresultant evenly distributed vegetationsupported the projects flock throughoutthe summer without the help of sup-plementary food Table 3). Despite theheavy rainfall, neighboring farmers wereforced to supplement their animals dietwith barley, straw and residues from theextraction of olive oil, due to unrotatedgrazing. Even without supplementaryfeeding, the weight of animals studied wasas much as 8.5 kg heavier than neighbor-ing flocks.

Table 2. Plant productivi ty (in kg) under di fferent grazing schedules.Annual Biannual Small Rhsnterium Artemisia Otherspecies species perennials suswedens campesfris shrubs Total(shrub) (shrub)

Continuous year-long 191 A25 167.459 67.223 225.429 5.098 46.104 702.938grazing k 70.55 k 26.42 f 15.69 k 29.77 f 2.59 k 17.59(Saad Boukl i)Spring-deferred 409.643 51.418 76.693 117.769 29.236 178.237 862.996,plotSummer-deferred 341.932 45.738 66.097 137.783 5.964 129.949 727.462plot 1 f 2.22 k 10.68 f 16.26 k 17.78 ? 2.79 k 17.85Summer-deferred 275.426 19.724 73.999 133.304 98.249 88.286 688.988plot2 k 39.98 k 8.98 k 16.02 k 35.20 k 30.08 f 41.81* Difference between these totals was significant at the 90 percent confidence evel.

Figure2. Predicted trends of desertifi cation ndexes with four different evelsof exploitation.

OGLAT MERTEBA STUDY AREAf20 O00 ecibrsla - AREAS DESERT/f/ED.

Hn(La?d only gmzed I Ha.(Landused for duo1 p u r p s e s ILevel 4

Level 3

4 O00E000 o 5 10 15 JOYears5 e v e l 2 Level 4Leve1 3Leve l 2O0000 5 10 15 20 25Years.

b - AVERAGE PR/MAUY RUNOFF CEFf C MIT FOR THE W O L E STUDY AREA. /K t1 (A v e ra g e yew]l 6 f

Level 4Leve l 3Level 2Level

o 5 10 15 2 xYeors.

Tons/ho.7 O006

5WO40W

3WO

%Xt 2 (mois t years I4 O t

Leve l 4::Eevel 38 Leve l 2L Leve l

O 5 10 15 2 0 2 5Years.c - CONSUMABLE PRIMARY Pht3DI/CTlV/TY O f THE GRAZED

LevelL e v e l 2

7 OW6 O005 O

L e v e l 3Level 4

( y e w w i th o verag e ra in fa l l l .

Leve1Level 2

Level 3Level 4

O 5 10 15 20 25Years .O 5 10 5 20 25Years.d- AVERAGE STORAGE O f WAER AVAILABLE TO VEGETATKN

Rv-mmLeve l I

K E Y95 Leve l 3 Leyel I - Exclusion f r w n graz ing

Level 2 - Ratioml regiowl land use.Level 3 - Upkeep of t h e a c lu al s y s te m ., ~85 Levd 4 - lnc rmse of fhe ac tua l p rac t ices o f lond useo 5 10 15 2 0 25Ywrs

LANDS.

138 AMBIO VOL 10 NO 2-3


5/8

Desertification andways to com bat itLarge areas of Tunisia are subject to de-sertification 7), primarily through windaction on denuded soils. Most soils aresandy, lack stability, and consist primarilyof coarse particles up to 80 percent).Overgrazing, disc plowing of fragilesoils, and harvesting of shrubs forbuildingmaterials and fuel are basic causes of de-sertification. However, the latter has de-creased in importance as butane gas isincreasingly replacing wood fuel inTunisia.In Oglat Merteba (8), studies over anarea of 20000 ha, have shown that themajor cause of desertification was discplowing. Trends in desertification and re-covery were simulated to the year 2000under four intensities of land use see Fig-ure 2 ) . Remedial suggestions include im-proved range management practices, ir-rigation of pastures and supplementaryfeeding of flocks, and limiting small grainproduction to only the most favorablesites.Additional experiments on methods ofcombatting desertification were carriedout at two sites area No. 3 in Figure 1)where overgrazing has been a problem.Early detection of sand movement is veryimportant. The movement can be either,toward erosion or accumulation. Meas-urements at Dar ez Zaoui showed that theoccurrence of ripple marks, fine undula-tions in the soil surface at regular inter-vals, is an early indicator of desertifica-tion 9). Furthermore, the percentage ofsurface area covered by these undulationsis a good measure of severity.Spring and summer deferred grazingtreatments were applied to plots where 40to 60 percent of the soil surface was co-vered by ripple marks. After five years,this surface was reduced to less than 5percent. The improvement was due to anincreased amount of vegetational residuescovering the soil surface, enough to pre-vent the movement of soil particles, andan increase in vegetation density suffi-cient to decrease the windspeed a t the soillevel (10).Methods for reducing losses of culti-vated soils were compared on experimen-tal plots surrounded by concrete ditchesso that eroded soil could be collected andweighed. The crop used was barley. Landcultivation included only disc plowing,even though an optimal experiment wouldhave used a sweep which does not over-turn the soil (11).In treatment 1, oases manure preparedfrom the feces of sheep and goats wasapplied to the soil, together with straw atthe rate of 2.2 tons per hectare. The soilwas then plowed and planted. Stubble wasretained after harvest. Treatment simplyretained stubble. In treatment 3 , manurewas plowed into the soil. St raw was addedafter planting, and stubble was uprootedafter harvesting. Treatment 4 uprootedstubble with no amendments.

Table3. Comparison of the weight of ewes in study area and in three neighboring locks.Average weight o f ewes by age categories, fromberkoussa (the youngest) to charef (the oldest) Supplementary eedingberkoussa holia reba

Average weight 15 42 23 49 37 14of three neigh-boringflocks in kg)

Project's flock 20.65 31 50 32 46average weight(in kg)Difference 5 22 8 01 - 4 68between theproject's andneighbors

sedasse jama charef31 88 30 52 31 80 From the first of August,200 g of barley as grain perhead per day and 300g ofstraw, 200 g of residuesofolive oil extraction36 13 34 55 40 30 None

4 24 4 02 C 8 50

Goats grazing. Studies by the authors and others suggest that goats alone do not cause great damage ovegetation unless they are pastured n mixed flocks with sheep.

Figure 3. Comparative soil los a- Treatment Oases manure addpdduring 1978-79. @ Treatment 2 No s traw added

2;2z ha straw hcorpora ted h s o r l b e fo re p la u g h ;q a n l ' ~ 7 8sr ib JlQ main ta ined upon harves t .no oases m anure added

ses with different treatments

0 - - T re a tm e n t 3 S t ra w a d d e d (2,2 t / h a )m .W l / 7 8oasestubble m a n u reprootedddedpon harves t0 -- rmhnent 4 No s t r a w a d d e dno oases m a n u re a d d e dsfubb le uprooted

Al l t r ea tm ent s were drsc p loughed

AMBIO, 1981 139


6/8

Alfa grass (stipe tenacissima)on lower mountain slopes.

Results are shown in Figure 3. Addingoases manure with straw added beforeor after plowing substantially reducedsoil losses treatments 1 and 3). Simplyretaining the stubble from one yearscrop treatment 2) did not produce asignificant improvement over the controltreatment 4).Table 4 shows barley yields for theabove four treatments plus the addition ofstraw alone. The latter increased yield by1.9 times compared to the control. Addingmanure and straw increased yield by 2.6times treatment 1) and 2.7 times treat-ment 3). These experiments show thatsimple techniques can be used to reducesoil losses and increase crop yields at thesame time.Drawing up of management proposalsThe studies were aimed towards landmanagement and rational land use,whether they concerned soil surveys orphyto-ecological inventories or experi-ments on evaluating the impact of the dif-ferent environmental and social factors.Hence the results obtained were in-tegrated into two main types of actionproposals for development: pilot areas forimproving rangelands, forage and animalhusbandry; and regional managementmodels 12).140

The case of the Bir Lahmar area will bethe only one presented in this paper.Although smaller in size, it includes themost basic characteristics of the othersdue to its diversity of soils and the changein land-use practices there.The Bir Lahmar irndu is an administra-tive unit located at the junction of theMatmatas Mountains and the Jeffara ofMedenin site No. 4 in Figure 1) wherevegetation, soil, and socio-economicstudies were carried out 12). It includesthree diffeent land units. One is amountainous area with traditional waterconservation structures, or jessours-little dams built with stones and ear th andplanted with olive trees or fig trees. Be-fore 1954, this area was the center ofagricultural activities. The second unit isthe pediment or lower mountain slopes.Previously used for grazing or Cultivatedfor small grains, it has now become thecore of urbanization. The third unit, orsteppe, located outside the pediment, is arather fragile sandy area with high eroda-bility, currently cultivated for smallgrains.The population previously depended onsubsistence farming, centered aroundcommunally maintained j e s s o ur s . How-ever, since 1954 traditional farming ac-tivities have disappeared.

Animal ploughing has been replaced bytractors, urbanization is taking place ra-pidly 13), and j essours no longer arecommunally maintained.Following flooding in 1969 the main e s -sours, which receive the first runoff andwhich are responsible for 30 percent ofagricultural production, were destroyed;it is predicted that their destruction willtrigger the chain disappearance of the oth-ers. Furthermore, the steppe was put intocultivation, and farming and overgrazingof this fragile zone have brought aboutdesertification.Regional management modelsA proposal for action was developed fromthe first phase of the project. It involvedsetting up eight main centers for demon-stration and popularization of range man-agement in the arid and pre-desertic partof Tunisia. Generally, the project con-sisted of managing small units of pasture-land from a few hundred to severalthousand hectares in size) by applying themost suitable forage production and ani-mal husbandry techniques on the basis ofa thorough knowledge of the natural andhuman environment. Most of the pilotareas have given conclusive results fromthe technical point of view, but extending

AMBIO VOL 10 NO -3


7/8

Table 4. Yields of grain barley. Each vertical column is the average of five statistical replicates (exceptfor s traw in which there are only three replicates).Yields of Treatments Manure added Manure and Straw added Contro l (includesbar ey before plowing, straw added after planting treatments2 and 4)grain straw added before plowingafter planting(treatment 3 (triatment IIn grams per squaremeter 85 89 25 82 05 10 22 61 33?r 10 80 31 60? 10 48In kilograms per 858 820 613 3 316hectare t 92 5 rt 102 t 108 k 104

the methodology to other areas has to beweighed against land appropriation andother land-use priorities.From these pilot areas, proposals forthe management of much larger areaswere prepared, and specific recommenda-tions were made for the threepedomorphological mountain, glacis orpediment and plain) units:111 moiintain areas: rehabilitation andmaintenance of j essours , with fruit treesfig and almond) planted in the mostfavorable parts, and forage bushescactus, acacia, Parkinsonia) in valleybottoms, wadi beds and the bases of hills.On glacis cereal culture improvement bybetter use of runoff water and by impro-ving soil working techniques and fertiliza-tion, since there is little regeneration ofthe natural plant cover.11he plain: limitation of cropping in or-der to preserve the most productiverangelands and to encourage the regenera-

tion of naturally-occurring species by con-trolling grazing. Dunes that have alreadyformed can also be fixed by plantingwoody forage species e s cacia cyano-phyl lo, Retama raet i im).Fruit crops grown with appropriatetechniques and in favorable areas situatedclose to villages in each of the three unitsdescribed above, are also advised.These proposals form part of an in-tegrated system of land managementbased on ecological principles and takinginto account essential nutritional require-ments. The problem is to know whetherthe local populations will accept the pro-posed solutions and strategies. Thesepoints are being examined in a socio-economic study which is currently under-way in Tunisia.CONCLUSIONSA considerable amount of data onecosystem dynamics of the pre-desertareas of south Tunisia has accumulated asa result of the research undertaken in thiszone. This data has been used to draw upaction proposals fo r land management ona fairly large scale, and decision makershave used these proposals as a basis forplanning the development of these areas.The implementation of the managementprogram of the area first studied, OglatMerteba, began about five years ago.

From the practical point of view, thedifficulties encountered in implementingthis program on a larger scale do not resultfrom the local population contesting thevalidity of the technical results, but aremore related to constraints such as theneed for grazing rotation.Popularizing the grazing technique,through persuasion and through incen-tives is part of the strategy employed inthe hope of ultimately combating de-sertification. In the past, considerable los-ses of livestock were frequent; now theyare rare. At the same time, there has beenadequate forage during the years ofdrought.The proposals formulated through theseresearch activities emphasize an in-tegrated and multidisciplinary approach tobasic resource management in order todiversify production and make the bestuse of southern Tunisias potential. Thisapproach also takes into account the re-quirements of the population, thusharmonizing the overall production objec-tives with the need to conserve naturalresources.Investigations are still continuing in or-der to improve the recommendations inthe light of a dynamic population. In thefinal analysis it is hoped that the experi-ence will provide guidelines for a land-usepolicy 14).

References and Notes1. C Floret, R Pontanier, Relations sol-climat-vg-tation dans quelques formations vgtalesspontanes du Sud tunisien-production vgt ale etbilan hydrique des sols. (Document technique No.1, Institut des rgions arides, Ministre delAgriculture, Mdenine, 1978).2. C Floret, E Le Floch, R Pontanier, F Romane,Modle cologique rgional en vue de la plan ifica-tion et de Iamnagement agro-pastoral des r-gions arides. (Document technique No. 2, Institutdes rgions arides, Ministre de lAgriculture,Mdenine, 1978).3. D and K Crocke r Bedford, in Tunisianpresaharanproject, progress report N o . 8 (USIIBP DesertBiome, U tah S tate University, Logan, 1977), pp.144-178.4. Basic problems and basic techniques in range re-search (National Academy of Sciences, NationalResearch Council, W ashington, 1962).5. F di Castri, Division des Sciences cologiques,Unesco, personal communication.6. N P Woodruff, F H Siddoway, Soil ScienceSociety of America Proceedings, 29, pp 602-608(1965).7. C Floret, E Le Floch, R Pontanier, Carte desensibilit la dsertisation en Tunisie centrale etmridionale Processus de dgrad ation en coursdes sols et d e la vgtation) au 1/100.000 (Sols deTunisie, Ministre d e lAgriculture, 8, pp. 4-68).

8. Oglat Merteba region, case stud y on desertifica-tion, U N Conference on desertification, Nairobi,August 29-September 9, 1977.9.Hierarchical classification of sand accumulationforms, in Dune Stabilization a survey of literatureon dune formation and dune stabilization,geographisches Institut Universitt Wiirzbourg,August 1977, Deutsche gesellschaft fiir Tech-nische Zusammenschaft, pp. 93-94.10. Classifying rangeland fo r conservation plann ing,Agricultural Handbook No. 235, (United StatesDepartment of Agriculture, Soil ConservationServ ice, 47 p. 1962.11. D W Fryear, Reducing wind erosion in the South-ern Great Plains. (Texas agricultural experimentstation, MP 929, Texas A and M Univ ersity, 1969,USA.)12 Recherche et dveloppement des parcours ducentre-sud tunisien, Tunisie, synthse des travauxraliss au cours du projet et recommandations(FAO, Rome, AG/DP/TUN/69/001).13. T Bouhaouach, Contribution i lanalyse socio-conorniaue de la rpion de Bir Lahmar (Institutdes rgi arides, -Ministre de lAgr ulture,Mde nine, 1980).14. This project is su pported jointly b y UN ESC O-MAB andi the United,Nations,Environment ro-gramme (UNEP).

I Georges Novikoff received his docto-rate in natural sciences from the Uni-versity of Montpellier in 1964 for hisresearch on relationships betweenhalophytic vegetation and soils inTunisia. At present he is principaltechnical adviser for the MAB 3 pro-ject o n arid lands in south ern Tunisia(UNESCO-UNEPhstitute of AridLands of Medenin). Earlier he was th eresident scientific coordinator of theTunisian pre-Saharan project spon-sored by the US/IBP Desert Biomeand Smithsonian Foreign CurrencyProgram. H e has been associ ated asa plant ecologist with a number ofstudies in land use planning at thesoil science sect ion at the Minist ry ofAgriculture of Tunisia and with var-ious range management studies inTunisia and Algeria. He s also Profes-sor of Range Managemen t at t he In-stitute of Arid Regions in Medenin.His address: Institute of Arid Re-gions, Medenin, Tunisia.Moham ed Skouri received his docto-rate in natural sciences from the Uni-versity of Paris in 1966 for wo rk onthe regulat ion of food intake in ru-minants in relat ion to the nutrit ivevalue of the diet. Subsequently, hewas Director of the Laboratory ofAnimal Husbandry and Forage Pro-duction at the National Inst itute ofAgric ultur al Research of Tunisia (IN-RAT), head of the Faculty ofAgricultural Sciences of the Uni-versity of Tunis, and from 1970 to1975, head of the Research Divisionof the Ministry of Agriculture. Hethen served until 1978 as PresidentDirector-General of th e Board of Ani-mal Production and Pasture Manage-ment of Tunisia. He now works forUNESCO as a specialist in arid landecology. His address: Division ,ofEcological Sciences, UNESCO, 75700Paris, France.

AMBIO, 1981 14


8/8

Balancing development and conservation in Saharan Tunisia

Documents

Transcript of Balancing development and conservation in Saharan Tunisia