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3.2.2 Biodiversity and desertificationMARIAM AKHTAR-SCHUSTER, UTE SCHMIEDEL & NORBERT JÜRGENS

SUMMARY: Recent changes to land tenure rights in drylands have not only provided new opportunities for increasing agricultural production. Changed access to the natural capital is in many cases also seriously affecting the ability of the utilised natural resources to regenerate naturally. In many drylands, the overex-ploitation of biodiversity, of soils and the of groundwater resources has led to their deterioration to the extent that these ecological damages will often not be reparable within the time horizon of a human lifespan. Desertification is an alarm signal for socio-ecological dysfunctions.

mariam.akhtar-Schuster@dlr.de

The problemApproximately 41% of the land surface experience highlyvariable rainfall, high temperatures and recurrent droughts.These areas are characterised as drylands. More than 2billion people, and thus, 1/3 of the human population livesin drylands (MILLENNIUM ECOSYSTEM ASSESSMENT Deserti-fication Synthesis Report, 2005). Despite these environ-mental constraints for land use, significant cultural,economic and political developments derive from thesehyper-arid, arid, semi-arid and dry sub-humid areas.Dryland biodiversity was the backbone for agriculturalinnovation. It contributed considerably to the developmentof human culture. Numerous cereals, legumes, cotton butalso farm animals originate from drylands. Thus,biodiversity is not only essential for the functioning ofnatural ecosystems, it directly offers numerous economicand non-economic values, services and benefits to society,such as food, medicine, fibres, forage, fuel and buildingmaterials. In many drylands, livelihoods completely relyon the local and regional natural capital. Therefore, anyqualitative or quantitative changes to the biodiversity candirectly impact on means to earn and sustain a living.Increasingly, humans are changing biodiversity to meet theirdemands or due to land mismanagement. Prime indicatorsof dryland mismanagement can be very unspectacular. Thedecline of a palatable species due to intensive grazing willoften not give rise to much concern as the process is gradualand biomass production usually does not change dramati-cally. Usually, desertification has reached an advanced stagebefore policy and society react. Often, the affected countrieshave other more urgent issues to solve so that actions to haltand combat desertification are even further delayed.

The MILLENNIUM ECOSYSTEM ASSESSMENT Deserti-fication Synthesis Report (2005) estimates that about 10 to20% of formerly productive drylands are presentlydegraded. Africa and Asia are very seriously affected bydesertification. This report estimates that approximately 1to 6% of the dryland people live in already desertified areasand underscores that desertification is one of the greatestenvironmental challenges. Governments in affected regionsare forced to develop measures for food security andsimultaneously delineate plans for safeguarding their

biodiversity. Social disruptions, rural poverty and popu-lation displacement are the ultimate outcome of these socio-ecological disorders. This is especially true for ruralhouseholds, whose economic stability directly depends onthe condition and on the availability of local or regionalnatural resources, and whose access to other sources ofincome generation are limited or non-existent.

Causes and effects of biodiversityloss and desertificationIn many drylands, biodiversity is currently undergoingdramatic changes which can ultimately lead to desertification(JÜRGENS 2005, 2006a). It can be assumed that losses ofspecies richness, the declining functionality of ecosystems,the invasion of new species, as well as changes to biomassproduction will continue and might accelerate in future.These changes are primarily associated to human activities.

This is due to continuing demographic developments,alternating social norms and values, economic andindustrial dynamics, urbanisation, poverty, past andprevailing land tenure systems, lacking land reforms, andthe implementation of new agricultural technologies whichare not adapted to the dryland ecosystems. A progressivenarrowing of the genetic potential has to be anticipated formany species in drylands, resulting in reduced adaptabilitytowards changing conditions. Thus, the ongoing changesto biodiversity foreshadow a dramatic loss of the potentialthat is embedded in the organisms. Replacement of locallyadapted plant strategy types by plantations or spontaneouslyspreading stands of invasive alien species has a severeimpact on ecosystem function and the sustainability ofnatural resources such as soil and water in particular. InSouth Africa, for instance, about 10 million hectare, i.e.8% of the land surface area of the country, are infested byinvasive alien plants which use about 7% more water thannative vegetation. In the national-wide poverty-relief-fundproject »working for water« the South African Depart-ments for Water Affairs and Forestry, of EnvironmentalAffairs and Tourism, and of Agriculture, employed 21,000previously unemployed individuals for clearing of aliens andecosystem rehabilitation (WORKING FOR WATER 2003). Othercomponents include the conservation of biological diversity,

Akhtar-Schuster, M., U. Schmiedel & N. Jürgens (2007): Biodiversity and desertification. In: Lozán, J. L., H. Grassl, P. Hupfer, L.Menzel & C.-D. Schönwiese. Global Change: Enough water for all? Wissenschaftliche Auswertungen, Hamburg. 384 S. Online: www.klima-warnsignale.uni-hamburg.de

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WATER AND CLIMATE CHANGE: POSSIBLE CONSEQUENCES 3.2

Abb. 3.2.2-1: In the Tiervlei communal land (left side ofphoto), severe grazing has changed the vegetation’s speciescomposition in arid rangelands in southern Namibia. Onthe right side controlled grazing maintains biodiversity.Photo Courtesy: Anke Hoffmann

and the building and empowerment of local communitiesthrough job creation and management initiatives.

The continuing fragmentation of ecologically intactregions in drylands will reduce the capacity for naturalrestoration processes. In many cases, the functionality ofbiodiversity will not be restored within the time horizon of ahuman lifespan. These developments will hamper regionaland local measures for maintaining food security. Thestability of rural, low-income households which depend onthe condition of the local biodiversity will be at a greater risk(KUIPER & MEADOWS 2002). Poverty will increase. Conflictswill rage over the use of the remaining pastures, the decliningarable lands and over diminishing water resources.Transboundary migrations and urbanisation will increase.

The growing number of environmental refugees whohave been forced to leave their lands due to the effects ofthe over-exploitation of the natural resources highlights theglobal extent of the socio-economic destabilisation processthat arises out of the local loss of biodiversity anddesertification.

In the arid rangelands of southern Africa, markedfence-line contrasts visualise the degradation process ofbiodiversity due to intense and uncontrolled grazing bydomestic livestock (SCHMIEDEL et al. 2003). Fig. 3.2.2-1(left side of the fence) clearly shows the impact of severegrazing on the vegetation cover. Investigations carried outby Bock (AKHTAR-SCHUSTER et al. 2005) underscore thatnatural resources in the communal land of Tiervlei(southern Namibia) ensure the mere survival of households.Domestic livestock still covers many essential functions inthe area, i.e. insurance, social status, and investment. Bockformulates that incomplete tenure rights, as a result ofapartheid policy, have a negative affect on today’s users’sense of responsibility for the natural resources in thecommunal lands of Namibia.

The right side of the photo (Fig. 3.2.2-1) shows, howthe establishment of rotational grazing and the regularmonitoring of indicator plants of the rangelands of aresearch station in southern Namibia are successfulstrategies to maintain the perennial grasslands which aredominated by the palatable Stipagrostis uniplumis. Specieswith low palatability or which are entirely unpalatable startdominating heavily utilised pastures.

In the Tiervlei communal area, the decline in plantcover has also had a severe impact on the diversity andabundance of most insects and mice. This can be tracedback to fewer dietary resources, to disruptions in the foodchains and to less structural diversity within the degradedplant cover. Cover and shelter are lost and the risk ofpredation is increased (HOFFMANN & ZELLER 2006; VOHLAND

et al. 2005). However, although reduced abundance anddiversity in the beetle species were observed on the degradedsite, an increase in the biomass of beetles (Coleoptera) could

be documented on the degraded communal land. Seemingly,the decline in the beetles’ numbers is compensated by theoccurrence of larger species (VOHLAND et al. 2005).Investigations by Petersen (in AKHTAR-SCHUSTER et al. 2005)show that the deterioration of grass cover in the Tiervleicommunal area as well as heavy trampling have alsoincreased soil disturbances and soil erosion.

The over-exploitation of biodiversity can also lead todramatically reverse effects in dryland ecosystems (JÜRGENS

2006b). Grazers such as cattle and sheep can lead to bushand tree encroachment. Intensively grazed grasslands aregradually converted into dense and partly impenetrable bushlands. A »green desert« emerges which again has an adverseaffect on farm production (HOFFMAN & ASHWELL 2001).

In order to solve the pressing issues on the causes andeffects of aggressive biodiversity exploitation in drylands,socio-economic activities and constraints which counteractthe sustainable use of biodiversity have to be identified.Instruments and indicators for documenting the ecologicaleffects of improper resources use, for maintaining theecological resilience and for supporting the naturalregeneration capacity of heavily used areas have to bediscussed. Participatory- and scientifically-based, however,economically affordable, and socially acceptablerestoration, protection and sustainable managementproposals for safeguarding biodiversity have to play a keyrole in the national policy action plans for regionaldevelopment in drylands.

Already in 1977, at the United Nations Conference onDesertification (UNCOD) in Nairobi, Kenya, a plan ofaction to combat desertification was formulated whichcomprised 26 recommendations that discuss the various andcomplex issues of desertification (MENSCHING 1977). Threedecades later, desertification has continued to spread, andhas destabilised the economic situation of rural households.

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Fig. 3.2.2-2: Members of local land user communities aretrained and full-time employed by a biodiversity researchinitiative as para-ecologists in order to strengthen the linksbetween science and local land users and to support thedevelopment of sustainable rangeland management tools.Photo: Ute Schmiedel.

Has science until now failed to convey deliverables tosafeguard environment and support sustainable develop-ment in drylands?

What can be done?Science has to develop methods to measure the problem.Integrated research techniques are necessary fordocumenting, monitoring and evaluating the past andpresent degradation of biodiversity within the context ofdesertification (JÜRGENS 2006). It is necessary to understandthe drivers and the consequences of change of biodiversityfrom the ecological as well as from the socio-economicpoint of view. The step from diagnosing the problem todeveloping remedial action and prevention plans is thepoint, where science concretely has to address the policylevel as well as the local stakeholders. Incentives forstimulating and introducing sustainable land use practiceshave to be discussed with policy makers in affected regions.Information is required to develop cost-efficient measuresto improve existing management and governance structuresfor the protection of indigenous biodiversity. Scientifically-led information communication networks can support theexchange of knowledge on best practices for safeguardingbiodiversity and combating desertification at the nationaland international level.

ParticipationThe lack of integration of affected local land users inresearch projects on sustainable development is a crucialsetback for combating desertification. Several decades ofapplied rangeland science have revealed that the develop-ment of sustainable rangeland management practicesrequires both, sound scientific information about ecologicalprocesses as well as knowledge of local land users on theecological, social, cultural and economic conditionsgoverning their environment. A participatory approach inresearch on sustainable development is indispensable inorder to translate research on sustainable development intoaction. Science and policy are increasingly aware of thenecessity of winning local land users for maintaining theproductivity of drylands. Also, traditional environmentalknowledge is invaluable for the understanding of drylandecosystems, and local land users can clearly name weakpoints in existing tenure systems which trigger themaximum exploitation of biodiversity. A clearly formulatedlegislation for sustainable resources utilisation, thedevelopment of decentralised and locally led resourcesmanagement systems as well as land tenure securityimprove incentives among rural land users to manage theirland in a sustainable manner.

Adaptable, user-friendly tools for the local monitoringof rainfall, fodder availability, livestock and rangelandcondition have to be designed for farmers and the extension

staff. These measures will improve the basis on whichfarmers will make decisions on their land use practices.Self-help systems have to be developed to locally monitorthe condition of the utilised biodiversity. Therefore, inseveral applied biodiversity research projects, land-usercommunities have been integrated in the planning andconduction of research activities and transformation ofproject results in user-friendly management tools. In theinterdisciplinary biodiversity monitoring and researchinitiative BIOTA AFRICA, members of local land-usercommunities are employed full-time and trained as para-ecologists (Fig. 3.2.2-2). By training and activelyintegrating para-ecologists in the research process, BIOTAAFRICA empowers them to take over substantial parts ofthe biodiversity monitoring tasks which were previouslycarried out by academic scientists and to facilitate researchresults for implementation in the land user communities(KRUG et al., in review).

ConclusionsHuman-induced changes to biodiversity are importantindicators of land mismanagement. Developing scientificstandards and a classification system for degradationindicators are invaluable for the assessment of thecondition of biodiversity. Continuous monitoring ofbiodiversity can assess the condition of biodiversity anddeliver information for immediate remedial action beforecostly restoration is necessary or irreversible damagesemerge. Collaboration with local communities in Nami-bia and South Africa underscores that the acceptance ofmeasures to safeguard biodiversity and to combat andprevent desertification strongly depends on whether localusers’ interests have been considered and whether theyperceive direct positive effects for their livelihoods♦