ANNEXES

Annex 1. Invitation to the LADA E-mail conference

This is to announce an International Electronic Mail Conference on the subject of Land Degradation Assessment in Drylands (LADA), in which your participation would be highly appreciated.

Background material on the LADA project, documents and results of the project until now are to be found on the Internet at the following site:

http://www.fao.org/landandwater/agll/lada

LADA is an international partnership project in support of the UN-CCD, funded mainly by GEF and FAO, implemented by UNEP and executed by FAO with significant contributions by the Global Mechanism of the UNCCD, MA, WRI, ISRIC and national institutes in several pilot countries.

The objective of this Electronic Mail Conference is to take stock of available land degradation assessment methods at global, national and sub-national scales and exchange expert views in order to arrive at a broadly agreed practical land degradation assessment methodology, to determine a minimum set of biophysical, socio-economic and institutional root causes, driving forces, factors and indicators involved, their applicability at different scales as well as the economic feasibility of monitoring them, particularly in dryland situations.

The conference will be moderated by Ms Mathilde Snel, supported by the FAO LADA task force. It will run in the first instance from Tuesday, 7 October until 8 November 2002 and will then become a continuing forum on the LADA Web site.

If you wish to participate, please send an e-mail message to [email protected] leaving the subject blank and entering in the first line of the message body the command: subscribe lada-l.

This message is sent to more than 1 000 well-known experts in various fields related to land degradation and desertification, but do not hesitate to send it on to colleagues we may have forgotten.

Annex 2. List of subscribers

Annex 3. List of contributors

Abdelkader Allali
Vice-Chair of the IPCC WG II
DPV. BP: 1387
Rabat. Morocco.
E-mail: [email protected]

Prof. Dr. Jorge Ares
Investigador Independiente
CONICET - Centro Nacional Patagónico
Boulvd. Brown s/n,
9120 Puerto Madryn
Chubut, Argentina
E-mail: [email protected]

José Benites
Technical Officer,
Food and Agriculture Organization of the United Nations
Rome, Italy
E-mail: [email protected]

Elisabeth Bui
Principal Research Scientist
CSIRO Land and Water, GPO Box 1666
Canberra ACT 2601, Australia
E-mail: [email protected]

Sally Bunning
Food and Agriculture Organization of the United Nations
Rome, Italy
E-mail: [email protected]

Andy Dougill
Leeds Environment and Development Group
School of the Environment
University of Leeds
Leeds LS2 9JT, U.K. www.env.leeds.ac.uk
E-mail: [email protected]

Planchon Fatou
Centre de Suivi Ecologique,
Dakar, Senegal
E-mail: [email protected]

Abbas Farshad
Department of Earth Science Analysis (DESA),
International Institute for Geo-Information Science and Earth Observation (ITC)
Enschede, The Netherlands
E-mail: [email protected]

Rogerio Ferreira
Instituto Voçorocas
ONG TORBA Network Soil & Society
Nazareno, Brazil www.torba-soil-society.org
E-mail: [email protected]

Vicente Espinosa Hernandez
Instituto de Recursos Naturale
Montecillo, Mexico
E-mail: [email protected]

Dr Mamadou Khouma
Chef du Laboratoire National de Recherches sur les Productions Végétales (LNRPV)
Institut Sénégalais de Recherches Agricoles
B.P. 3120
Dakar, Senegal
E-mail: [email protected]

Dominique Lantieri
Food and Agriculture Organisation of the United Nations
Rome, Italy
E-mail: [email protected]

Charles Lilin
Paysages et Médiation
Montpellier, France
E-mail: [email protected]

Ramez Mahjoory
Institute of International Agriculture
Michigan, U.S.A.
E-mail: [email protected]

Philippe Mahler
Consultant, France
E-mail: [email protected]

Mr. Timo Maukonen,
Senior Programme Officer
Division of Early Warning and
Assessment (DEWA)
United Nations Environment Programme (UNEP)
P.O. Box 30552
Nairobi, Kenya www.unep.org and www.unep.net
E-mail: [email protected]

Freddy Nachtergaele
Food and Agriculture Organization of the United Nations
Rome, Italy
E-mail: [email protected]

Dr. David Niemeijer
Environmental Systems Analysis Group
Department of Environmental Sciences, Wageningen University
P.O. Box 8080
6700 DD Wageningen, The Netherlands
[email protected]

Dr. Pierre Ozer
Fondation Universitaire Luxembourgeoise (FUL)
Avenue de Longwy, 185
B-6700 ARLON, Belgium
Tel: 32(0) 63230975
Fax: 32(0) 63230800
Email: [email protected]

Kevin Parris
Policies and Environment Division, Agriculture Directorate, OECD,
2 Rue Andre-Pascal,
75775 Paris CEDEX 16, France
E-mail: [email protected]

Raul Ponce-Hernandez
Environmental and Resource Studies Program and
Department of Geography
Trent University, Peterborough,
Ontario, Canada.
E-mail: [email protected]

Mark Reed
Leeds Environment and Development Group
School of the Environment
University of Leeds
Leeds LS2 9JT, U.K. www.env.leeds.ac.uk
E-mail: [email protected]

Michel Robert
INRA et Ministère de l'Ecologie et du développement durable
France
E-mail:[email protected]

Andries Rosema
EARS Environmental Analysis and Remote Sensing Ltd
Kanaalweg 1,
2628 EB Delft, The Netherlands www.ears.nl
Email: [email protected]

Alain Ruellan
Professor Doctor Emeritus
President of TORBA Soil and Society
2 Boulevard Berthelot
34000 Montpellier - France
Email: [email protected]

Maurizio Sciortino
Ente per le Nuove Tecnologie, l'Energia e l'Ambiente (ENEA) CR Casaccia
Via Anguilarese 301
00060 Rome, Italy
Web: www.enea.it
E-mail [email protected]

Ashbindu Singh
Division of Early Warning and Assessment (DEWA),
United Nations Environment Programme (UNEP),
Sioux Falls, South Dakota 57198
U.S.A.
Email: [email protected]

Ben Sonneveld
Centre for World Food Studies of the Vrije Universiteit
De Boelelaan 1105
1081 HV Amsterdam, The Netherlands
E-mail: [email protected]

Professor M. A. Stocking
School of Development Studies and Overseas Development Group (DEV/ODG)
University of East Anglia (UEA)
Norwich NR4 7TJ, U.K. www.uea.ac.uk/dev/faculty/stocking.shtml
E-mail: [email protected]

Dr. Mohamed Talbi.
Coordonnateur de l'Observatoire Intégré des Zones Arides et Désertiques
Institut des Régions Arides
Medenine, 4119 Tunisia
E-mail: [email protected]

Dr Lamourdia Thiombiano
Senior Soil Resources Officer
FAO, Regional Office for Africa
P.O. Box 1628
Accra, Ghana
E-mail: [email protected]

Andrew Warren
Department of Geography
University College
London, U.K.
E-mail: [email protected]

Godert van Lynden
International Soil Reference and Information Centre (ISRIC)
P.O. Box 353
6700 AJ Wageningen, The Netherlands
E-mail: [email protected]

Anthony Young
Professor, Land Resources
University of East Anglia, U.K.
E-mail: [email protected]

Juliane Zeidler
Secretariat of the Convention on Biological Diversity (CBD)
Montreal, Canada
E-mail: [email protected]

Annex 4. Introductions, discussion items and questions sent ot participants for each week's theme

Week 1. Land degradation assessment methods, indicators and conceptual frameworks

Land degradation is a complex process involving a diversity of biophysical as well as socio-economic factors that largely vary in their spatial and temporal dimensions. A key objective of LADA is, therefore, to develop a framework for land degradation assessment that accommodates these information sources in order to support policy makers and stakeholders in their evaluation on future land use scenarios. The LADA project aims to operationalize this framework at a national scale, the level where most policy decisions concerning the land use take place and where the portfolio of environmental action plans is administered. This exercise should also lead to methodologies that will be applicable at a global scale.

The development of such a framework includes a reconnaissance phase in which tools, methods, and indicators are identified that evaluate the state and causes of land degradation. Indicators on the degree and impact of land degradation should clearly reflect the stakeholders' opinion on criteria of land performance, while causative indicators will be used to explain the degradation process in its geographical dependence on biophysical variables and land management practices. Land degradation assessment methods at the national scale should aim for a balance between data availability and applicability. Therefore, the LADA project is considering the use of interpolation and redressing techniques that maximize the use of existing information (e.g., in national census or household surveys), while maintaining a cost-efficient, timely routine assessment.

The first week of the LADA email conference starts with a request to provide input on methods that may used for land degradation assessment. We anticipate that various participants have important insights on, and experiences with, a variety of land degradation methods. We shall be grateful to hear of your triumphs (and challenges) in using such methods.

Since this email conference has as a major goal the development of feasible land degradation indicators, please share your views on the usefulness (or not) of indicators. Do you feel that the use of indicators will adequately help assess land degradation? If so, why? If not, what alternatives would you propose? We also submit for discussion a draft Driving force-Pressure-State-Impact-Response framework that is envisioned to help in global and national land degradation assessment. Is such a framework helpful in achieving the LADA objective to develop a replicable and easily usable methodological framework for land degradation assessment? Are there alternative frameworks that you think may be more useful?

We welcome feedback and suggestions and thank you in advance for your input.

Discussion items and questions

1. A main objective of LADA is to develop tools and methods to assess land degradation. What types of methods do you propose may be used to assess land degradation? These methods need to be able to integrate biophysical, socio-economic and institutional aspects of land degradation at differing scales. A review of some methods can be downloaded at:

ftp://ftp.fao.org/agl/agll/ladadocs/redameth.doc.

2. Are indicators useful to evaluate land degradation? If so, why? If not, what alternatives do you propose? Can indicators sufficiently capture the dynamics and interactions with regards to agroecological, socio-economic, and cultural processes, as well as to human decision-making processes, knowledge differentiation among stakeholders, and issues of perception? (e.g., at local, technical and policy levels on degree, impacts, and causes of land degradation and opportunities to reverse land degradation).

3. LADA proposes a Driving force-Pressure-State-Impact-Response (DPSIR) framework to evaluate land degradation. Do you find this framework useful? What advantages and disadvantages do you envision with the use of such a framework?

The draft DPSIR framework can be downloaded at:

ftp://ftp.fao.org/agl/agll/ladadocs/dpsir.doc.

Week 2. National land degradation assessment

Lack of information on land degradation at the national level has stifled many efforts to arrest a further decline of lands' productivity. Decision makers voice that information is lacking on where land degradation is occurring, why it occurs, and how it may be reversed. Based on our discussion last week, participants noted that while indicators may be used to help provide information on land degradation, such indicators need to be selected and used with great care. Therefore, this week participants are invited to take on this challenge and identify a minimum set of Land Degradation Indicators (LDIs) that may be used at the national level to assess the degree of land degradation (i.e., state indicators); explain the underlying causes (pressure indicators); and describe efforts to reverse land degradation (response indicators).

Please specify for each suggested indicator: the data required, a description of each data set, the proposed data collection method(s), data availability, applicability to agro-ecological zones (or other conditions, such as kinds of land management), and critical thresholds. Ideally the proposed indicators should be based on existing data (e.g., national agricultural census or farmer surveys). If, however, you propose to collect new data sets we would like you to consider the cost-effectiveness of conducting such a survey. Since LADA aims to develop a practical methodological framework for routine national land assessment, preference should be given to using data collection methods that have a solid scientific base (are replicable and quantifiable) and that are economically feasible. Furthermore, we encourage suggestions on using modelling to predict changes for proposed indicators. We will appreciate your attaching articles that may provide further detail on the indicators and methods proposed. Please refer to your own experiences (successes and failures) in providing input to these issues.

As a follow-up to this discussion, next week's theme will be the utilization of local data, knowledge and descriptive studies. We will discuss how these information sources can be used to (1) strengthen our understanding on the underlying causes of and responses to land degradation and (2) to test our national assessments. Furthermore, we will discuss methods that may be used to link data that are collected at the local level with national land assessments.

We look forward to your feedback and thank you in advance for your input.

Discussion items and questions

1. A set of criteria are indicated below that may be used to help select a minimum set of key indicators for national land degradation assessment. Are there other criteria that you feel should be added? Alternatively, is this list too restrictive?

• the indicators should ideally be based on existing data

• if new data are collected, cost-effective methods should be used

• robust measurements - that provide replicable results - should be used

• data need to be routinely available or collected

• indicators need to be clearly defined

2. What are the most important indicators that can be used to assess the status of land degradation in drylands for national level assessment?

Where applicable, please refer to your own experiences (successes and failures). Please list for each proposed indicator:

• data required

• description of each data set (e.g., soil, soil carbon, climate, water, vegetation, biodiversity, economic productivity, institutional)

• data collection method(s) (e.g., sampling, remote sensing, ...)

• data availability

Relevance general or only for a specific AEZ, farming systems or other category

• critical thresholds if applicable

3. What key (minimum) indicators can be used to explain the underlying biophysical, socio-economic, and institutional causes of land degradation for national-level assessment?

Please list proposed indicators according to their importance and complete for each indicator the sub-questions mentioned under question 2.

4. What key indicators can be used for national level assessment of responses to reverse land degradation?

Please list proposed indicators according to their importance and complete for each indicator the sub-questions mentioned under question 2.

5. How feasible do you feel it would be to routinely collect data for these indicators towards developing a national monitoring network that regularly (e.g., bi-annually) monitors and informs on land degradation?

Week 3. Local indicators and assessment

Land degradation varies for each location under different land management practices. Therefore, land degradation assessments at the national scale - the intended main focus of the LADA project - should be verifiable and based on observations that are obtained at the local level. Then, policy and decision makers can compare and build on results of national assessments to formulate locally explicit recommendations towards arresting further land degradation.

In last week's discussion several key Land Degradation Indicators (LDIs) for national land degradation assessment were identified. Many of the proposed indicators are based on existing or easily obtainable data (e.g., soil organic carbon and soil moisture), although these need to be verified in the field. Furthermore, new data sets for which no data currently exists (land use, access to land and water, input/output relations, etc.) need to be collected at the local level. This week, participants are invited to provide input on what types of local level data sets (especially socio-economic) are scarce or non-existent but need to be integrated in national land degradation assessments, and how these data sets can be cost efficiently and reliably collected. Where possible please indicate what types of stratification and sampling strategy can be used (e.g., to account for varied agroecological systems and land use management schemes). Once collected, how can these data sets be linked with national level assessment? For example, one method that is gaining respect (e.g., in the realm of poverty mapping) has been the use of a small area estimation technique that links national census data and local surveys (e.g., farmer surveys). Do you feel this method would be useful to LADA? Are there other methods that you feel may be helpful?

A second theme to be addressed this week came up several times during the discussions so far: the need to strengthen national-level assessment (that tends to rely on robust methods and quantifiable data) with local descriptive evaluations (that more extensively explain the underlying causes and consequences of land degradation over space and time). In particular, such descriptive evaluations can help disentangle some of the complex linkages between the causes of land degradation and the consequences (socio-economic, institutional, etc.) - a key challenge to scientists developing land assessment methodologies. Such local evaluation can also provide a rich understanding on why land degradation is occurring (e.g., due to institutional policies, cultural practices, gender roles, poor access to information and technology, lack of democracy, etc.). How can local descriptive evaluations be cheaply, easily and regularly integrated in national assessment? Would it, for example, be useful to routinely conduct descriptive evaluations in identified hot spots -severely degraded areas- and bright spots -showing improvement or resilience-?

Please refer to your own experiences (successes and failures) in providing input to the above noted issues. We thank you in advance for your feedback.

Discussion items and questions

1. What types of issues need to be evaluated at the farm or community level to gain a better understanding of:

• the underlying socio-economic, institutional, and biophysical causes of land degradation?

• responses to cope with land degradation?

• the degree of land degradation?

2. Based on the above key issues, which data sets (especially socio-economic) are scarce (or non-existent) that at the minimum need to be integrated in national land degradation assessment (e.g., land use data and precise land management information)? Please describe how such data sets may be collected cost-effectively and reliably. Where possible, indicate stratification, sampling, and other relevant issues.

3. What types of methods do you feel can successfully be used to link local data and information with national-level land degradation assessment? Do you feel a small-area estimation approach may be useful? (see short explanation in the above text)^[1]

4. Local analytical studies on land degradation often describe the underlying socio-economic, institutional, and biophysical circumstances that contribute to land degradation in great detail and with very specific information. How could these descriptive studies be integrated in national land degradation assessment? Would it be feasible, for example, to routinely conduct participatory rural appraisals (or similar methodologies) within identified land degradation hot spots and bright spots?

Week 4. Global land degradation indicators, network for drylands, and next steps

Land degradation is recognized as a global problem and is a major focus of such international conventions as the Convention to Combat Desertification (CCD) and the Convention on Biological Diversity (CBD). Obtaining a thorough understanding of the current condition of the world's drylands and the causes and consequences of its degradation is a key objective of LADA. During the past weeks we have discussed various indicators (and key issues in developing such indicators) that can be used for national land degradation assessment. How can sub-national data - upon which such national assessments rely - be generalized to the global level and what does this imply for the harmonization of methods at the local level? Could the use of existing global data sets containing sub-national information be complementary^[2]? Conversely, can the sub-national information in this growing number of global data sets be used to help strengthen national assessments?

This week's agenda has been broadened to discuss next steps to help LADA further identify key indicators and methods for land degradation assessment. This may include the development of user assessments to identify key questions, and the subsequent identification of indicators, collection of data, manipulation of data (e.g., through the use of models), etc. Please find attached a draft outline on Next steps for LADA (Annex 5) to begin this week's discussions on the subject. We would be interested in getting more feedback from participants on this and other proposals how LADA should develop a methodological framework to cost-effectively and routinely monitor land degradation, and to help decision makers develop policies to arrest land degradation.

With the development of national capacities to monitor land degradation and to design policies to combat land degradation, how could such national operations benefit from, and contribute to an international network for dryland assessment? What should this network's role be? Would it be helpful if a main role of such a network would be to act as a data repository of national and global land degradation assessment?

Discussion items and questions

1. How can national land degradation assessments be generalized from the sub-national to the global level? If countries are using different variables to measure and assess land degradation over space and time, is such transformation feasible? If not, what alternative methods can be used to assess land degradation at the global level?

2. What are your reactions on some of the proposed next steps for LADA. Do you feel these proposals are feasible towards developing routine monitoring of land degradation for drylands? If so, why? If not, what type of refinements do you propose?

3. What are your thoughts on the feasibility of developing a network for dryland assessment? What should be the role of this network? Should a key role of such a network be to serve as a data repository of national and global land degradation assessments?

Annex 5. Next steps for LADA: draft outline for discussion

Stage 1: User needs assessment and National stakeholder meeting

• identify key issues in political and economic terms: goods and services approach

Stage 2: Inventory

• identify and collect existing data sets; review biophysical data (e.g. available radar and satellite images for land cover mapping) as well as socio-economic data

• identify important missing data sets (e.g. socio-economic)

• identify indicators (geared to user needs)

Stage 3: Implementation

• use appropriate stratification and sampling (more in hot spots) in a baseline assessment for a monitoring scheme

• develop models - including models to link biophysical and socio-economic data

Stage 4: Analysis of results

• determine cause, state, and effect (frame data within the DPSIR framework)

• conduct participatory local surveys in hot and bright spots to help formulate policy recommendations

• discuss results with stakeholders

Stage 5: Dissemination of results and Policy recommendations

• link results with solutions and policy recommendations

• disseminate results (e.g., meetings with policy makers, brochures, etc.)

Stage 6: Monitoring and evaluation

• repeat

The Figure A5.1 outlines the basic steps and the relationships among them in some more detail.

FIGURE A5.1 Scheme of basic steps in LADA

Squares = actions; ovals = output; dotted line = recursive evaluation.

Annex 6. Land qualities and potential indicators for land degradation assessment of dryland areas

Introduction

This paper presents an overview of land qualities and lists of biophysical and socio-economic indicators potentially useful in the assessment of land degradation in drylands. A wide range of indicators may be needed for the assessment of land degradation, its direct and underlying causes, its effects on livelihoods and the promising remedial or preventive approaches. In contrast, the assessment of the nature, severity, extent and distribution of different kinds of land degradation, generally based on mapping techniques, will require restriction to a small number of indicator variables. These may be intrinsic or may be proxies, validated within a specific range of agro-ecologies or socio-economic conditions.

Tables A6.2-5 appended to this paper list potential indicators for use at four scales: global, national and regional, watershed or village, and farm. The indicators are subdivided into biophysical, demographic, institutional and socio-economic groups. The position of each indicator in the DPSIR framework is indicated. Tables A6.6-10 provide annotated, more detailed lists and selected references on socio-economic and institutional indicators, organized by main issue: insecurity, incapability, lack of opportunity or income, disempowerment, and lack of incentive or inadequacy of policies.

Background

Dryland systems are under threat from a combination of socio-economic and biophysical changes that are culminating in a downward spiral of land degradation. The lack of reliable and comparable information on land degradation in drylands has been a major constraint to the implementation of Rio Conventions, particularly UN-CBD and UN-CCD.

The root causes, and at the same time consequences, of land degradation and desertification are often poverty and food insecurity combined with harsh climatic events such as drought. This leads to excessive pressures on often fragile ecosystems, the natural resource base, and the adoption of resource depleting survival strategies by the land users.

One of the immediate causes of land degradation is inappropriate land use, including overgrazing, excessive irrigation, and intensive tillage and cropping. The resulting degradation of soil, water and vegetation cover and loss of both soil and vegetative biological diversity affect ecosystem structure and functions. The primary driving forces of land degradation are policy and institutional distortions or failures in the public or government, private or market, civil or community sectors, as well as civil strife.

At global and eco-regional scales, land degradation results in the degradation and loss of unique ecosystems and their endemic components of biodiversity, and the breakdown of traditional livelihood systems. It threatens especially culturally unique agro-pastoral and silvo-pastoral farming systems, and nomadic and transhumance systems. Its consequences are widespread poverty, hunger and mass migration, requiring emergency assistance on an unprecedented scale and frequency, and creating a potential cycle of debt and indebtedness for the affected populations. The nature of interrelationships and thresholds between these technical, institutional and policy factors at different scales and in their temporal dimensions are still poorly understood.

Land qualities to be taken into account in assessing land degradation

Dryland degradation often starts with crop expansion into ecologically fragile zones and poor soils not suitable for sustained cropping, and formerly used by herders or acting as a buffer zone between farmers and herders. As long as the carrying capacity of the land is not exceeded, sustainable land use is possible. A solid vegetation cover can be kept and precipitation infiltrates into the soil, remaining available for vegetation.

However, if land use pressure exceeds the carrying capacity, the ability of the vegetation to recuperate decreases. Unprotected soil is very vulnerable to slaking, which will entail increased runoff, diminishing the availability of water for biomass production. Moreover, the higher albedo of bare soils results in lower surface temperatures because of higher reflection. This results in reduced cloud formation and thus decreased rainfall. The final result is accelerated degradation.

The processes causing or accelerating dryland degradation are varied but can be reduced to the following four:

• Cropland management or cropping practices damaging the land

• Deforestation

• Overgrazing

• Irrigation systems or practices inappropriate to the land conditions

These processes are often interlinked and have multiple consequences. Still some disagreement exists about the root causes of dryland degradation: whether it is climatic change leading to severe droughts or increased human activity in sensitive areas. However, it must be kept in mind that human activities, when badly managed, aggravate the consequences of drought.

Land degradation may take six different forms, all of which lead to loss of soil productivity:

• Erosion by water

• Erosion by wind

• Salinization and sodication

• Chemical degradation (including nutrient depletion)

• Physical degradation (including compaction)

• Biological degradation

Soil degradation can be defined as a process that reduces the actual or potential capacity of the soil to produce goods or services. Land degradation refers to a loss of intrinsic qualities or a decline in the suitability for one or more specific uses.

A number of land qualities therefore need to be evaluated in order to assess the degradation status of the land under consideration.

Land cover

Land cover can be described by using the eight major land cover types as developed in LCCS (Di Gregorio and Jansen, 2000). Not all eight are relevant for dryland systems, but the fact that this classification is widely accepted will facilitate comparison at global and national scales. Each land cover type is described by a number of "pure" land cover classifiers, describing the nature, extent, density, etc. of each cover.

Landform

Landforms refer to the shape of the land surface. They should be described by their morphology, and not by their genetic origin or the processes responsible for their shape. The dominant slope is therefore the most important criterion, followed by relief intensity.

Soil qualities

A description of the soil surface in bare areas should give a good idea of the ability of the soil to allow water to infiltrate or of the presence of shifting sands or hardpans. For instance, the slaking of the aggregates at the soil surface by rain impact leads to formation of a dense crust, and partial sealing of the pores in the soil by the detachment and washing in of soil particles.

Soil profile description will give additional information on the behaviour and properties of the soil, especially the occurrence of compacted layers, macropores from macrofauna and discolouration of certain layers. Systematic description of the soil profile needs expert observation, and a number of databases are available. Alternatively, a method developed by ICRAF can be used: The reflection spectrum of bare soil is measured and compared to spectral libraries. These spectral libraries are constructed from soils sampled from georeferenced locations, for which a soil fertility index is calculated from the following variables: pH, clay, silt, ECEC, Ca, Mg, K, P, organic C and mineralizable N. The association of specific reflection spectra with value ranges of the soil fertility index is then used to map soil quality and soil constraints for larger areas on the basis of remote sensing imagery.

Reasons and effects of land degradation

It is essential to understand the question why degradation has occurred before any control measures and restoration actions can be designed. Figure A6.1 shows a suggested chain of explanation.

The conditions faced by farmers are remarkably diverse. The options available to poor farmers to improve their land are much more constrained than those available to richer farmers, who have easier access to labour, livestock, land, credit and cash. Even within a single farm, the management of land may vary considerably between different fields. Typically certain fields tend to receive far greater concentrations of labour and nutrient inputs, while others are more extensively managed.

At village level, issues include the different kinds of land available, the overall pressure on farmland and its availability, access to grazing and forage resources, the importance of labour flows between households, as well as location in relation to markets. At the national level, factors of relevance relate to macro-economic policy, input-output price ratios, access to credit, institutions and legislation regarding tenure and land management, approaches to research and extension policy, markets and infrastructure.

FIGURE A6.1 Chain of explanation of causes of land degradation (after Blaikie, 1989)

The diversity at different scales has important implications for how land degradation is assessed, and still more important, for how best to support land users in improved management of their land resources. This diversity has major implications for design of technical options, extension approaches and policy frameworks.

Soil erosion provides a clear example of such diversity. Erosion is a natural phenomenon. However, in the assessment emphasis should be given to accelerated or human-induced erosion. Most erosion can be classified as water or wind erosion or deposition. Mass movement can be seen as another major category. Erosion can be further classified according to its severity and details of the process.

Land degradation by erosion has effects at the site of the detachment as well as downslope or downstream, where the excess water and soil from the detachment area may cause flooding and sedimentation (off-site). Therefore the effects of land degradation should be assessed both locally and within the watershed or village area as a whole, and be related to social, cultural and economic aspects.

On-site effects of land degradation

The process of land degradation usually starts with a decrease in organic matter content of the top layer of the soil. This results in a rapid decline of biological activity in the soil. A deficit in the humus balance leads to destabilization of soil aggregates and a reduction of soil fertility. Macropores are filled or collapse, and infiltration rate and water-holding capacity are drastically reduced. Less vegetation can be sustained and more bare soil will be unprotected from the impact of rain or wind.

The most important on-site effect of land degradation is a gradual decrease in soil fertility, soil productivity and eventually crop yield and animal productivity. Land degradation is more damaging to the quality and productivity of some soils than others. The effects on productivity depend largely on the thickness and quality of the topsoil and on the nature of the subsoil. Many soils are shallow or have some undesirable properties in the subsoil that may adversely affect yields. Productivity will decrease as the topsoil becomes thinner, or as water storage capacity and effective rooting depth are decreased. Chemical imbalances may occur because of the mixing of the topsoil with subsoil material, which may be more acid or less fertile.

Off-site effects of land degradation

The greatest single pollutant of surface water, on a volume basis, is soil sediment. It reduces the value of streams for home and industrial use, for recreation and as habitats for fish and wildlife.

Nutrients and pesticides washed or leached from the fields may also cause pollution problems when they reach streams or other water bodies. High levels of nutrients in water induce rapid growth of algae, reducing the available oxygen in water as well as releasing certain toxins. Soil sediment, nutrients and pesticides increase the costs of water purification for public water supplies.

As less water can infiltrate on degraded land, more rainwater will disappear as runoff. The result is that serious downstream flooding is more frequent, resulting in destroyed crops, lands, infrastructure and buildings, and in killing people and animals. Fertile and productive soils can be spoiled when thick layers of coarse sediment are deposited on them (by flooding or as wind-blown sands). Sediment is also deposited in reservoirs, lakes and streams, which leads to reduced storage capacity, reduced power generation, increased costs and reduced habitats for biodiversity.

Indicators

Indicators are statistics or measures that relate to a condition, change of quality, or change in state of something valued (Dumanski and Pieri, 1996). They provide information and describe the state of the phenomena of interest. Indicators of land quality are statistics that report on the condition and quality of the land resource, but also on the cause-effect relationships that may result in changes in quality and the responses to these changes by society. If a number of indicators is reduced by aggregating them according to some formula, then these are called indices. Indicators differ from other statistics (processed raw data) in their significance to a specific problem.

As the project aims at identifying driving forces and impacts of land degradation at different scales, the indicators are classified accordingly: usable at global, national, agro-ecological zone or farming system scale. Indicators at different scales need different degrees of detail; for instance for problem identification and awareness raising, general descriptive indicators are needed. Strategy, policy or project formulation require more detailed indicators, also focusing on the causes of a certain problem and on projections of impacts (modelling, scenarios, benefit/cost and multicriteria analysis) so that effective and realistic responses can be formulated. For the actual implementation of policies related to land quality, national goals and targets need to be established as well as local ones, which need more quantitative indicators. At this stage the social and economic context becomes more important. To evaluate the effectiveness of policies and actions, quantitative indicators are needed that illustrate how the situation has changed in relation to the goals and targets. Assessment activities should preferably be formulated together with users (or even better upon request of users) in order to create more direct links between users and producers of information.

Land quality indicators are needed to address major land-related issues of national and global significance, such as land degradation in dryland areas, as well as policy-related questions on sustainable land management. Land quality indicators report on the biophysical condition of land, but indicators are needed as well on how the land is being managed and on the policy and social environment, which may facilitate improvements in land management or give rise to practices that foster deterioration.

A so-called DPSIR (Driving forces-Pressures-State-Impacts-Responses) framework (Table A6.1) is one of the approaches that can be used to structure and classify information and to assist in the identification of the key set of indicators that best describe how farmers and other land users are managing their land and the impacts of this management. The DPSIR is a convenient representation of the linkages between the pressures exerted on the land by human activities, the change in quality of the resource, and the response to these changes as society attempts to release the pressure or to rehabilitate land that has been degraded. The interchanges among these form a continuous feedback mechanism that can be monitored and used for the assessment of land quality.

Land degradation and the resulting environmental problems are predominantly induced by human activities. Only when the causes and the impacts of the resulting pressures on the system are known can adequate responses be formulated. To qualify and quantify the driving forces, pressures, state, impacts and responses, indicators need to be found that adequately represent the various aspects of the complex situation.

The challenge is to find those core indicators that are sufficiently representative and at the same time easy to understand and measure on a routine basis. Indicators should be SMART: specific, measurable, achievable, relevant and time-bound (Schomaker, 1996).

In the case of LADA, indicators may help to make an assessment and to develop baseline information and undertake monitoring. These activities serve two purposes:

• to detect and identify the type of degradation and assess its severity; and

• to determine and analyse the cause-effect relationships involved with a view to identifying trends and taking remedial action.

Indicators for the first purpose may be used to assist in relatively simple and factual assessments at any scale. Appendix tables 2-5 may be of use in this regard. The potential indicators to be used for the second purpose, e.g. in a DPSIR model, are more numerous and complex. Their relevance and the feasibility of their use tend to decrease from local to global scales: diagnoses and interpretations are easier to develop locally, whereas the generalizations required at national or global scales make the use of indicators more problematic. Appendix tables 6-10 contain material that may be useful in the assessment of the causes of land degradation, its impacts and possible corrective or preventive responses.

In the assessment of the cause-effect relationships in land degradation, the two functions of humans need to be taken into account: people are both agents and victims of land degradation.

The use of indicators for LADA

• Several issues need to be considered in deciding on the usefulness of indicators for the LADA project:

• The systematic assessment of current land uses can be hampered by too many detailed data that are difficult to interpret, lack baseline information from which to compare change, or are inconsistent over time or over the geographic area (USDA, 1994).

• As natural resource variables generally change slowly, particularly the soil-related ones, the monitoring interval for identifying trends in relevant indicators may well need to be as long as a decade. This time span can possibly be reduced by using proxy indicators and relating them to existing historic data.

• Because of the dynamic aspects of land management, a flexible and adaptive process approach is essential for monitoring the quality and quantity of land resources (water, soil and plant nutrients) and for determining how human activities affect these resources and how their activities are affected by land degradation. For example, as the natural resource base is being degraded, first the proportion of palatable species in grazing lands tends to be reduced. There may be increasing stock movement; the amount of open water (ponds) or flow rates of boreholes may be diminishing; the carrying capacity will be reduced, resulting in a decrease of cattle relative to small ruminants. Less cattle may be available for agricultural activities such as ploughing and thus a shift from two-oxen to one-ox ploughs may take place.

• To avoid dangers of aggregation, the focus of the assessment should be on the diversity and dynamics of the systems. Key questions will be:

  - What factors result in land improvement or decline?

  - What pathways of change are evident and how are these linked to broader livelihood strategies?

  - What institutional and policy factors are important to encourage more sustainable strategies in different settings?

• Most important when using indicators is the question: "Does the change in the particular indicator chosen really matter"? (Scoones, 2001)

• It may be useful to define the significance of indicators in the context of specific major agro-ecological zones and specific ranges of socio-economic conditions.

• For the assessment at farm, village or watershed scale an effective communication channel needs to be constructed jointly by land users and technicians so that they will understand each other's language and concepts. Local indicators derived from an intuitive integration of changes of land quality need to be translated into scientifically used terminology to allow aggregation at national and international scales (Barrios et al. 2001).

• National assessments and monitoring should permit future refinement of the assessment at a global scale.

Conclusions

This brief paper and the appendix tables of indicators already show the dimensions and complexity of the use of indicators for LADA. It now appears urgent to address the questions how indicators should be used in LADA methodology, and for what purposes; and to concentrate on what is feasible.

In the case of LADA, indicators may help in making an assessment as well as in the establishment of baseline information and subsequent monitoring. These activities have two distinct purposes:

• to detect and identify the type of degradation and assess its severity; and

• to determine and analyse the cause-effect relationships involved with a view to identifying trends and taking remedial action.

Indicators for the first purpose may be used to assist in relatively simple and factual assessments at any scale. The potential indicators to be used for the second purpose, e.g. in a DPSIR model, are far more numerous and complex. Their relevance and the feasibility of their use tend to decrease from local to global scales: diagnoses and interpretations are easier to develop locally, whereas the generalizations required at national or global scales make the use of indicators more problematic.

Detecting and monitoring changes in land degradation, which are usually gradual, is more demanding in terms of quantification and replicability (standardization) than a one-time assessment. It would be useful to identify which indicators could be used as qualitative indicators and which require semiquantitative estimation or precise measurement.

Another consideration complicating the use of indicators for environmental assessments is that indicators may in a sense be a negation of the diversity of ecosystems. When an indicator is used as a common yardstick to measure and monitor one element in different ecosystems or socio-economic conditions, it may be a source of misunderstandings and misinterpretations. In the case of land degradation, natural and human-induced processes are often inextricably associated (e.g. salinization, erosion, sand deposition) and an indicator may not have the same weight or relevance in different environments.

Acronyms

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