Rachid BOUKCHINA "Case studies of indicators evaluation at local level using direct observations and modelling methods"
UNCCD 2nd Scientific Conference Economic assessment of desertification, sustainable land management and resilience of arid, semi-arid and dry sub-humid areas 9-12 April 2013 - Bonn, Germany Session 4.3 : Indicators for DLDD and SLMCase studies of desertification indicators evaluation at local level in Arid Zones of Tunisia using direct observations and modeling methods Presented by: Rachid Boukchina & Mongi SghaierResearch team: Ouessar M., Fetoui M., Ouled Belgacem A., Khatteli H. and Taamallah H. Institute of Arid Lands (IRA) – Tunisiarachid.firstname.lastname@example.org www.ira.rnrt.tn
OverviewThe ecosystems and the agro-systems of thearid zone of Tunisia are the most affectedsystems by desertification process in thecountry. The constraints faced by thesesystems are both natural and anthropogenic.These constraints and others create newecological, socio-economic conditions for whichthe traditional modes of natural resourcemanagement are ineffective.In the last decades much effort has been putto combat desertification in arid area ofTunisia. Several measures aimed at achievingagro-pastoral development on these systemshave failed for a variety of reasons includingthe lack of environmental knowledge. 2
Monitoring Desertification at local scaleIn Tunisia, until recently there was no effort putin place to monitor impacts of anti-desertification management and to evaluatetrends in desertification process.In this context and with the support of nationaland international partners the Institute of AridLands (IRA) has implement an researchprogrammes (UNESCO, DYPEN, CAMELIO,ROSELT/OSS, DNSE/OSS) for monitoringdesertification at local scale (Arid ZoneObservatories Network). 3
Scheme of integration of the local environmental observation in the Monitoring Evaluation national design in Tunisia N.C.S.DNational scale M. Environment UNCCD Focal pointRegional S. développement régionaux de décisionnels , CRDA etc… régionaux, conseils Centres Arid Zones Observatory développement)… ( comités locaux décisionnels OuaraLocal S. Bou Oued Centres locaux Faouar J’bil Hedma Menzel Graguer Jeffara Dekouk Sidi Toui de Habib Roselt /OSS Biodiversity
ROSELT/OSS Menzel Habib observatory Main characteristics Localisation Lower Meridionales Plains Area 113100 ha Climate Lower arid Mediterranean stage with mild winters ecosystems Steppes and agrosystem Steppes : Rhanterium suaveolens, Arthrophytum Vegetation scoparium, Artemisia campestris Fauna Very scarce Population 11330 inhab. Economic Pastoralisme , agriculture (cereal Activities cropping, arboriculture), 5
ROSELT/OSS Menzel Habib observatory Bou Hedma Localisation lower southern plains Area 75000 ha arid inferior stage with mild Climate winters Steppe and ecosystems woodland savanna Vegetation Acacia raddiana Fauna the antelopes Addax and Oryx Population 15000 inhab. Economic Agriculture (cereal cropping, Activities arboriculture) livestock production, 6
Monitoring approaches ROSELT/OSS Methodological Guidebook1. Bio-physical data set 2. Socio-economic data setClimate: Human population: rainfalls number meteorological data locationSoil: education pedology, organization surface conditions, Economic parameters: soil fertility Farm incomeWater: Non-farm income groundwater salinity, Infrastructure: Evaporation soil erosion control devices;Vegetation & Fauna: Water management; yields, roads, spatial distribution, schools, . . . flora & fauna diversity. 7
ROSELT/OSS framework: main outputs Establishment of Environmental indicators:Reference states (To) Diachronic/synchronic - Bio-physical data - Historical data -Socio-economic data - Official statistics - Remote sensing Simulation models/ Socio-economic indicatorsDecision Support Tools 8
50 0 100 150 P(mm) 200 250 300 350 400 1971-72 1972-73 Drought period 1973-74 1974-75 1975-76 1976-77 1977-78 1978-79 1979-80 1980-81* Sep 2012 to Mar 2013 1981-82 1982-83 1983-84 1984-85 1985-86 1986-87 1987-88 1988-89 1989-90 1990-91 1991-92 1992-93 1993-94 1994-95 years and 14 surplus years (P>110% of P) 1995-96 1996-97 1997-98 1998-99 1999-00 2000-01 2001-02 2002-03 2003-04 2004-05 2005-06 2006-07 2007-08 Environmental indicators: Annual rainfall 2008-09 2009-10 2010-11 2011-12 2012-13 P was 143 mm and showed 19 years of deficit (P<80% of P), 4 normal Great inter-annual variation: between 1971 and 2013*, mean rainfall (P)
Environmental Indicators: Land Use Change (LUC) 1976 (T0)April 1976: (Escadafal, 2006) April 1989:Transect SE / SO (gray): Drought 1987 – 1989Plain is dominated by steppes Decrease of annual crops (red)Rhanterium suaveolens (beige) and and appearance of mobile sandannual crops (red). dune (yellow).
Environmental Indicators: Land Use Change (LUC) Year 2000 Year 2009The comparison of the evolution of land use in MH observatory between1976 (baseline year) and 2009 reveals: rangelands have beentransformed into rainfed and irrigated cropping lands: • the increase of rainffed cropped lands (olive trees) with water harvest management; • the expansion of irrigated land using saline groundwater; and • good vegetation quality in protected area (Rhanterium steppes).
Environmental Indicators: Landscape Répartition des zones morphologiques (Ghram, 2007).Unité Superficie (ha) % Total "disappearing“ ofTerrasse de glacis 655 1 mobile sand duneBas-fonds 2660 2Cône de déjection 913 1Garaas 1669 1Glacis dablation 6392 6Plaine 84455 75Sebkha 1534 1Versant 14722 13Total 113000 100
Environmental Indicators: anti-desertification managementProgress (ha) in implementation of soil erosion and water harvesttechniques between 1987 and 2009 (CRDA-Gabès, 2010):- Water budget at watershed scale (infiltration, evaporation, runoff)- Soil conservation (erosion, fertility)
Environmental Indicators: Groundwater salinity TDS (g/L) <3 3 to 5.5 >6 Nb Wells 2 38 29 (%) (3) (55) (42) From 1987 to 2005, the total number of exploited wells for agriculture irrigation decreased from 237 to 69 . 14
Environmental Indicators: Soil quality in irrigated land CE (ms/cm) 0 0 5 10 15 20 25 -10 -20 Depth (cm) -30 -40 4 cropping seasons -50 -60 -70 -80 -90 Reference plot 2 cropping seasons Significant trends have been noted in soil salinity in irrigated land. Measure made during different cropping seasons indicate an increase in soil electric conductivity from close to 1 to 22 mS /cm. High EC values are the result of submersion irrigation. 15
Socio-economic indicators: Population & growth rates The Menzel Habib population dynamics during 55 years show three phases: - from 1956-1966 decrease of population - from 1966 to 1984 increase of population (36%) - from 1984 to 2010: (11974 to 11330 hab. ) and during two decades a negative growth rates were observed for men
Socio-economic indicators: Age structure Year 2004 Year 1996 Year 2010The comparison of the age structure between 1996 and 2010reveals a small family size and a gradual declining of thepopulation: migration (Gabes city).
Socio-economic Indictors: Land TenureIn Menzel Habib observatory, trends in agriculture speculation varywith land tenure: • Cereal cropping under communal governance • Olive trees cropping after land privatisation
Flora Indictors: Haddej & Bou Hedma NP 200 mm 158 mm 120 mm 52 mmProtection period since 1980The results obtained show that the specific flora diversity parameters (plantrichness, Shannon-Weaver and equitability indexes) double inside comparedto outside of the parks. The majority of species, which develop only insidethe parks and are very rare outside (non protected area). The results showthe significant link between variation in vegetation frequency and rainfalllevels (P < 0.05). Ouled Belgacem, A. et al. (2009)
Importance Non-farm income Agriculture investment Population Livestock production 1960 1984 1994 2004 Temps
Simulation Models for Desertification Monitoring SIEL (Loireau et al. 2007) SIELO (Fetoui et al. 2012)- Bio-physical / Socio-economic data -Landsat: Land Change Cover (LCC)- Historical data / Official statistics -Landscape use- Remote sensing Local Environmental Information system for Information Systems operational desertification ROSELT/ OSS SIEL model monitoring at Local Scale SIELO model Diagnostic of natural Spatialized& prediction resource indicators of desertification Specific (Landscape) & of future evolutions Global Indicators of risks / scenarios resource use desertification risks 22
SIEL & SIELO tests : Menzel Habib observatory & O. Oum Zessar Watershed Different land use scenarios controlled by farming activities and integrating the stakeholder perspectives were simulated and results confirm the pastor vocation of Menzel Habib observatory and highlight the risks to be embedded following the intensification of olive trees, cultivation of cereals and irrigation. Sghaier et al. 2008
Conclusion ROSELT/OSS concept framework has been sufficiently tested and is operational for Tunisian Observatories ant the obtained outputs converge to the UNCCD strategic objectives (1 and 2); Modeling land use scenarios change and its impact in local scale are helpful to investigate the interactive mechanism between land use system and desertification process; and However there are several difficulties and challenges facing the need establishment of reference status, indicators decision tools for the local scale: • the complexity of the desertification (temporal and spatial variation) ; • multiple indicators are needed to represent different forms of natural resources degradation. • work remains to improve the efficacy of methods for model development, testing, validation, and application.