Background Paper 1
FAO/Netherlands Conference on the Multifunctional Character of Agriculture and Land

The document was prepared by Michel Pimbert under the guidance of Linda Collette, Secretary of the Interdepartmental Working group on Biological Diversity for Food and Agriculture at FAO. Important inputs were received from the members of the Working group in particular the chair person of the group, Mahmud Duwayri, including Murthi Anishetty, Devin Bartley, Sally Bunning, David Cooper, Louise Fresco, Keith Hammond, Peter Kenmore, Christel Palmberg-Lerche, Clive Stannard, Tiina Huvio, Doug Williamson and Maria Zimmermann. Further valuable contributions and suggestions were provided by other technical specialists, including Nadine Azzu and Rene Gommes from FAO and from a number of other organisations and institutions.

Richard Trenchard from the Executive Bureau of the FAO/Netherlands Conference on the Multifunctional Character of Agriculture and Land was responsible for final editing of the document and its incorporation into this volume.

Throughout the world human communities have played a central role in shaping nature's diversity and its associated functions. Biological diversity has contributed in many ways to the development of human culture, and mankind has in turn influenced biological diversity. As an example, gourds (Lagenaria siceraria and Luffa spp.) show tremendous varietal diversity and have been selected for a multitude of use and functions, including containers, pipes, scrubbers, floats, musical instruments, penis sheaths, ornaments and food. Plants and animals, both wild and cultivated, have been combined in complex and diverse agroecosystems in terrestrial and aquatic environments. At the broader landscape level, recent scientific evidence suggests that virtually every part of the globe - from boreal forests to the humid tropics- has been inhabited, modified and managed for millennia. Over time, human influence has shaped the expression of agricultural biodiversity at the genetic, species, ecosystem and landscape levels.

The present paper is a contribution to the FAO/Netherlands Conference on the "Multifunctional Character of Agriculture and Land-MFCAL" that will take place in Maastricht The Netherlands, in September 1999. This background paper focuses on the relationships between agricultural biodiversity and the functions of agro-ecosystems at different spacial and temporal scales. Selected examples are used to highlight the multiple functions of agricultural biodiversity and its links with rural livelihoods in a range of ecological and economic settings. The paper is divided into three parts. Part one draws from the MFCAL approach (see below), and in particular focuses on the contribution made by agricultural biodiversity to 1) food and livelihood security 2) production and environmental sustainability and 3) rural development. Part two identifies the forces which impact on agricultural biodiversity. Part three concludes by outlining some of the policy and institutional reforms needed to sustain agricultural biodiversity and agro-ecosystem functions.

The MFCAL Approach provides the overall referential framework for this paper. The approach recognises that the first and foremost role of agriculture remains the production of food. It stresses however, that agriculture and related land use activity can also deliver a wide range of non-food goods and services, influence the natural resource system, shape social and cultural systems and can contribute significantly to economic growth. The approach also focuses on the trade-offs and synergies that can exist between these different functions.

The first dimension of the multifunctional character of agriculture and related land use concerns food production and the contribution that this makes to food security. Food security has been defined by FAO as a situation in which all people at all times have physical and economic access to sufficient, safe and nutritious food to meet their dietary needs and food preferences for an active and healthy life. There are three dimensions implicit in this definition: availability, stability and access. Adequate food availability means that, on average, sufficient food supplies should be available to meet consumption needs. Stability refers to minimising the probability that, in difficult years or seasons, food consumption might fall below consumption requirements. Access to food draws attention to the fact that, even with bountiful supplies, many people still go hungry because they are poor and unable to produce or purchase the food they need. In addition if food needs are met through exploiting non-renewable natural resources or degrading the environment there is no guarantee of food security in the longer-term.

Current concerns for food security stem from both the unacceptability of current levels of food insecure people (at least 800million people) and the recognition that agriculture will have to feed an increasing human population, forecast to reach 8 000 million by 2020, of whom 6 700 million will be in developing countries. In most developing countries, the majority of the poor live in rural areas and depend on agriculture for their livelihoods. Expanding food production to feed this increasing population, while alleviating poverty through gainful employment in agriculture, is a formidable challenge.

In addition to food production and the vital contribution that it makes to food security, the MFCAL Approach recognises three further broad functions 1) environmental 2) economic 3) social.

The Environmental Function. Agriculture and related land use can have beneficial or harmful effects on the environment. The MFCAL approach can help to identify opportunities to optimise the linkages between agriculture and the biological and physical properties of the natural environment. The environmental function of the MFCAL Approach is relevant to a number of critical global environmental problems including biodiversity, climate change, desertification, water quality and availability, and pollution.

The Economic Function. Agriculture remains a principal force in sustaining the operation and growth of the whole economy, even in highly industrialised countries. Valuation of the various economic functions requires assessment of short, medium and long-term benefits. Important determinants of the economic function include the complexity and maturity of market development and the level of institutional development.

The Social Function. Both the maintenance and continuing dynamism of rural communities are basic to sustaining agro-ecology and improving the quality of life (and indeed, to assuring the very survival) of rural residents, particularly of the young. On another level, the capitalisation of local knowledge and the forging of relationships between local and external sources of expertise, information and advice are fundamental to the future of existing rural communities. Social viability includes maintenance of cultural heritage: for we know that in many instances, societies still identify strongly with their historical origins in agrarian communities and rural lifestyles.

Agro-ecosystem functions are partly determined by the social goals of farmers, pastoralists, forest dwellers, fisherfolk and gardeners,- men, women and children with their own definitions of well being and their different priorities, rights, capabilities and knowledge. These social goals include economic, cultural and often aesthetic values as well as those of biological production. Depending on circumstances, preference may be given to short term maximisation of specialised productivity based on a single crop or to the diversity and persistence of production. These factors influence the way in which biodiversity is managed from the level of a discrete production unit (pond, field, swidden garden) right up to the larger landscape that is continuously transformed through the interplay between human agency and ecological processes (e.g. forests, pastoral landscapes, coastal zones and mangroves). Both natural processes and human management have generated and sustained a vast array of genetic, species and ecological diversity. In turn, this agricultural biodiversity performs many different socio-economic and environmental functions which are closely interrelated.

Given the strong historical link between rural livelihoods and the components of biodiversity that are managed in different ways for different purposes, agro-ecosystems necessarily include by definition people and their institutions as well as the agricultural biodiversity that they co-create and use. This inclusive view is implicit in the concepts and definitions jointly developed by the FAO and the Secretariat of the Convention on Biological Diversity (see Box 1). Considering agricultural biodiversity through such a holistic framework encourages the kind of methodological pluralism that is key to understanding the structure and functions of agricultural biodiversity in time and space.

Livelihood systems are diverse in rural areas and vary among different cultural groups and in different regions of the world. They commonly rely on a mix of wild foods, agricultural produce, remittances, trading and wage labour. Empirical evidence from many different locations suggests that rural households do engage in multiple activities and rely on diversified income portfolios. Contrary to received wisdom, the actual contribution of agriculture to livelihoods can be quite low in today's fast changing rural areas. In sub Saharan Africa, for example, a range of 30-50 % reliance on non-farm income sources is common but it may reach 80-90% in Southern Africa (Ellis, 1999). Household decision making continually adjusts to the changing nature of the environment, local economies and governance. At higher levels, it is simply impossible to predict the relationships between agro-ecosystems and households, particularly in resource-poor areas where there is much biological and social diversity.

The tendency for rural households to engage in multiple occupations is often mentioned, but few attempts have been made to link this behaviour in a systematic way to agricultural biodiversity and its multiple functions. In reflection of sectoral interests and disciplinary specialisations, the conventional point of entry for scientific research, management and policy has been to focus on selected components of agricultural biodiversity (e.g. plant genetic resources). However, this approach often leads to a mismatch between standard development interventions and diverse local realities, needs and priorities. Reversing this approach requires putting people with their assets, activities, and complex livelihoods at the centre of analysis (Chambers, 1997). The functions of agricultural biodiversity thus need to be situated and mapped out within a total livelihood context (IIED, 1995, 1998; Pimbert 1999).

Dynamic and complex livelihoods usually rely on plant and animal diversity, both wild and in different stages of domestication. (Box 2).

A diverse portfolio of activities based on the contributions of agricultural biodiversity (e.g. crop cultivation, harvest of wild plant species, herding, fishing, hunting) helps sustain rural livelihoods because it improves their long term resilience in the face of adverse trends or shocks. In general, increased diversity promotes more flexibility because it allows greater possibilities for substitution between opportunities that are in decline and those that are increasing.

Many rural people, regardless of whether their agro-ecosystems are predominantly pastoral, swidden or based on continuous cropping deliberately incorporate wild resources into their livelihood strategies (Table 1). Nor is livelihood diversification based on such wide use of agricultural biodiversity the exclusive preserve of rural households in developing countries. In Poland for example, wild bush and berry fruits are important for local consumption and for export, with Vaccinium myrtillus being the principal export species at present (over 30,000 t/year) followed by Rubus spp., Sorbus aucuparia, Sambucus nigra, Prunus spinosa and Rosa spp. (Glowacki, 1988).

Different types of agricultural biodiversity ("cultivated", "reared" or "wild") are used by different people at different times and in different places, and so contribute to livelihood strategies in a complex fashion. Understanding how cultivation, herding, fishing, collection, use and marketing of different types of agricultural biodiversity are differentiated by wealth, gender, age and ecological situation is essential to evaluate their overall economic value. Understanding this differentiation within communities is essential because there is great variation in wealth, ability, age and power in every rural society. For example, wild resources are particularly important for the food and livelihood security of the rural poor, women and children, especially in times of stress such as drought, changing land and water availability or ecological change. These groups generally have less access to land, labour and capital and thus need to rely more on the wild diversity available. In India, the poor obtain 15-23% of their total income from common property resources, as compared with 1-3% for wealthier households (Jodha, 1986). In Zimbabwe, some poor households rely on wild fruit species as an alternative to cultivated grain for a quarter of all dry season meals (Wilson, 1990). Whilst wild food species supply vital nutritional supplements to all diets based largely on carbohydrate rich staples, they are crucial sources of vitamins and minerals for children. Children are often the most frequent collectors and consumers of wild fruit (Scoones et al, 1992).

The degree to which the resources of agricultural biodiversity are important for local people's livelihoods affects the appropriateness of policies on resource management and on incentives for conservation and sustainable use. Comparing the economics of biological diversity use with other livelihood options can help assess people's willingness to sustain biodiversity as part of a livelihood strategy. There is however no single valid economic approach for doing this. Combining economic concepts with participatory research does nevertheless allow for a more comprehensive valuation of agricultural biodiversity, recognising not only the financial value, but also the indirect and non use values. The insights thus gained into the relative and changing seasonal importance of different types of agricultural biodiversity for livelihood security can be quite startling. For example, "wild" agricultural biodiversity may provide a significant proportion of total household incomes, particularly where farming or herding is marginal. In parts of Botswana, where unpredictable rains make farming a risky business, basket making from the wild palm Hyphaene petersiana, and beer brewing from the wild fruit Grewia bicolor provide a more secure income source, especially for women (Bishop and Scoones, 1994). Other local level valuation studies of agricultural biodiversity conducted in a total livelihood context show that many wild resources have significant economic value by preventing the need for cash expenditure and providing ready sources of income to cash poor households, often yielding a better income than local wage labour (IIED, 1995).

The cultural and spiritual values of some parts of agricultural biodiversity can sometimes be considered as more important than monetary values. Many rural communities designate certain biological diversity-rich areas of land or water as sacred. Sacred groves, for example, are clusters of forest vegetation that are preserved for religious reasons. They may honour a deity, provide a sanctuary for spirits, or protect a sanctified place from exploitation; some derive their sacred character from the springs of water they protect, from the medicinal and ritual properties of their plants, or from the wild animals they support (Chandrakanth and Romm, 1991). Such sacred groves are common throughout southern and south eastern Asia, Africa, the Pacific islands and Latin America (Shengji, 1991; Ntiamoa-Baidu et al, 1992). The spiritual values of sacred places on land or water are often inextricably tied with the functions that their associated agricultural biodiversity may provide in maintaining the health of the ecosystem. For instance, in a ranking exercise conducted to show the relative importance of different values derived from savannah woodlands in Zimbabwe, villagers explained that one of the most important aspects of their woodland was the sacred areas it contained. Honouring and preserving these sacred areas according to the wishes of the ancestral spirits is essential for good rainfall. The wide range of consumption benefits derived from the woodland were ranked lower than these spiritual ecosystem functions, as they could not exist without the rains, which in turn depend on the sacredness of the woodland (Hot Springs Working Group, 1995).

The rich tapestry of locally unique agricultural biodiversities represents, at the global level, a huge amount of diversity between species. Out of the 250,000 plant species that have been identified and described, some 30,000 are edible and about 7,000 have been cultivated or collected for food and the provision of other goods and services at one time or another (Wilson, 1992). World-wide, several hundred animal species including mammals, fish, reptiles, molluscs and arthropods also contribute to food and livelihood security.

Diversity within species is also remarkable among those plant and animal species that have been domesticated for crop and livestock production by innovative rural people. The inherent variation within farmers' crop varieties (landraces) is immense for cross-pollinated species such as millet or maize. For self-pollinated crops such as rice and barley, and for vegetatively propagated crops like potatoes and bananas, individual varieties are less variable, but the number of landraces developed may be very high. Estimates of the distinct number of varieties of Asian rice (Oryza sativa) range from tens of thousands to more than 100,000 (FAO, 1998) while some communities in the Andes grow as many as 178 locally named potato varieties (Brush, 1991). A review of the immense genetic variation in plant crops, and its contribution to food and livelihood security, has recently been compiled by the FAO (FAO, 1998).

Livestock keepers have also generated and safeguarded considerable intra-specific diversity through their animal husbandry. In India alone, 26 different breeds of cattle and 8 breeds of buffalo, 42 breeds of sheep and 20 breeds of goat have been identified along with 8 breeds of camel, 6 breeds of horses, 17 breeds of domestic fowl,- in addition to native pigs, mithum and yak. World wide, it is believed that the total number of mammalian and avian livestock breeds is between 4,000 and 5,000 (FAO, 1995). Important contributions of animal diversity to food and livelihood security are summarised in box 3.

Domesticated plant varieties, animal breeds and diverse agro-ecosystems are largely sustained through local peoples' crop husbandry, livestock management practices and fishing techniques. Conservation of diversity is through active use in different ecological and economic settings.

Each species in an agro-ecosystem is part of a web of ecological relationships connected by flows of energy and materials. Whilst each species may occupy a specific ecological niche (e.g. primary producer, specialist or generalist consumer, decomposer) it is involved in sustaining many different agro-ecosystem functions and environmental processes, either directly or indirectly. In this sense the different components of agricultural biodiversity are inherently multifunctional and contribute to the resilience of production systems whilst providing environmental services at the larger landscape level. However, it is important to note that some species may play a key driving role in forming the structure and overall behaviour of agro-ecosystems and landscapes at different scales. There is indeed growing evidence that the diversity and functional complexity of all ecosystems can be traced to a small number of critical structuring processes, some of which are mediated by critical "keystone species" (Holling et al, 1995). An example is the suite of 35 species of insectivorous birds that mediate budworm outbreak dynamics in the eastern boreal forest of North America (Holling, et al, 1995).

Farmers, herders and fishermen have often enhanced the multiple functions of agricultural biodiversity through choice of genetic material, design of cropping patterns, development of crop and livestock production systems, land and water management practices as well as institutional arrangements. Local knowledge about the properties and dynamic roles of agricultural biodiversity is crucial in this connection. For example, the mal monte (bad weeds) and buen monte (good weeds) management systems of Mexican farmers recognises that the vegetation community as a whole must be managed to promote those aspects that are beneficial (Chacon and Gliessman, 1982).

In low external input farming, different components of agricultural biodiversity are usually combined to give practices finely tuned to the local biophysical and socio-economic conditions of individual farmers, herders and fish culturists. Natural processes mediated by agricultural biodiversity are favoured over external inputs and by products or wastes from one component of the agro-ecosystem become inputs to another. An example is the mulberry grove-fishpond system in the Pearl River Delta of China. In this multifunctional system, the white mulberry (Morus alba) tree produces organic substances (mulberry leaves etc). These are used to feed silkworms that, in turn, produce their silk and chrysalides. The fallen parts of the mulberry tree and the excrement of the silkworm are applied to the fishpond where they are converted into fish biomass. The excrement of the fish, as well as other unused organic matter and bottom mud are returned to the mulberry grove as fertiliser, after being broken by a diverse suite of benthic micro-organisms. The agricultural biodiversity harnessed by the fish culturalists allows for the closing of nutrient cycles and efficient production in time and space. Fish polycultures are thus made up of species that dwell in the upper, medium and lower layers of the pond, as well a fish species with different feeding habits (e.g. plankton feeders, herbivorous fish, benthic mollusc feeders, and omnivorous fish) (Ma, 1985; Zhong, 1982).

In more specialised, high input farming based on the use of high yielding varieties, agricultural biodiversity helps sustain many production functions such as soil organic matter decomposition, pollination and pest control. In the USA or Australia for example, farmers may manage cover crops primarily to save soil and water in intensive orchard production systems. However, the species chosen will usually perform other functions in the agro-ecosystem. In addition to protecting against soil erosion, cover crops usually enhance soil structure, improve soil fertility and nutrient cycling as well as play a role in pest management by providing habitat heterogeneity and preserving a favourable balance between pests and predators. Depending on the species, trees can also provide fodder for animals, so increasing the number of internal linkages within the agro-ecosystem. These examples highlight the multiple functions of agricultural biodiversity and are intended as a reminder that functions are discussed one by one in this report only for the sake of convenience.

Decomposition and nutrient cycling functions. The crop plants, trees, livestock and fish deliberately chosen by farmers are the main determinants of the diversity of the flora and fauna that makes up the decomposer subsystem (Swift and Anderson, 1993). Available evidence shows that decomposer communities are highly diverse and are centrally involved in nutrient cycling, organic matter dynamics and other ecosystem functions. Detailed knowledge on the extent and functions of this diversity is limited; there is relatively more information on the functions of soil biodiversity than on the dynamics of decomposer communities in aquatic environments. Some functional groups in soils are widespread in distribution (e.g. nitrogen fixing bacteria, mycorrhizal fungi and predators of soil borne pests) whilst other like earthworms and termites are more restricted in their distribution. A gradually emerging picture structures soil biodiversity into a series of more or less spatially independent guilds (Swift, 1976; Lavelle et al, 1998). The spatial separation between distinct guilds (surface litter, root litter, rhizosphere guilds ...) allows decomposer organisms to co-exist whilst containing communities of organisms that are functionally equivalent. For instance, several ecological guilds of earthworms can be recognised in humid tropical soils with different roles in litter transformation and as "ecosystem engineers" (Lavelle et al 1998). Through their activities of feeding, burrowing and casting, they modify the physical, chemical and biological properties of soil and thus its ability to support above ground vegetation. Together with termites, different species of earthworms are among the key functional groups in humid tropical soils. At least 42 native and exotic earthworm species common in tropical agro-ecosystems have been identified as able to resist disturbances linked to agriculture and agroforestry practices and build up sizeable populations in these environments.

The sensitivity of decomposer functions to farm management practices is also evident in the mechanised agriculture of developed countries. Comparisons of the soil biological diversity in biodynamic, organic and conventional farms in Switzerland show higher species diversity and functional levels in biodynamic and organic plots than in conventional systems. The significantly higher biomass, diversity and functional activity of soil micro-organisms, earthworms, ground beetles, staphilinids and spiders found in biological systems are largely due to the organic amendments and more selective plant protection measures used in the biological systems (Mader et al, 1996).

In high input-high output agriculture, microbial diversity is also a central component of integrated plant nutrition systems (IPNS) that aim to maximise the efficiency of plant nutrient supplies to crops by complementing the use of on- and off-farm sources of plant nutrients. Nitrogen fixation through bacteria (notably Rhizobia spp) and algae (Azolla spp) as well as phosphorus cycling via mycorrhizal fungi species are particularly noteworthy in this connection (Alexandratos, 1995; Gray and Williams, 1971).

Microbial diversity is generally known to mediate nutrient cycling. However, there are few detailed studies of the dynamic role of micro-organisms in structuring landscapes and agro-ecosystems at different spatial and temporal scales. A long term study of African savannahs has shown that the productivity of large mammalian herbivores, -upon which the human economy of the savannah is based, is dependent on water availability acting as an "on-off" switch for the mineralisation of nitrogen, phosphorus and sulphur. Some 80% of the mineralisation is performed by the diverse soil micro-organisms which respond dramatically to the presence of water or rain. Where the immediate limiting resource in broad leafed savannahs is nitrogen, the key effect of water is to control the availability of inorganic nitrogen by modulating the functions of soil microbial diversity rather than control photosynthesis. The interaction between water and micro-organism activity thus sustains soil fertility. In turn, soil fertility has a profound effect on savannah ecology by determining not only plant production but also what fraction of it is edible and which species of plants and animals will be present (Scholes, R.J. and Walker, 1993). Livestock production is thus closely dependent on the dynamic interactions between water availability and the activity of a diverse suite of soil micro-organisms in these semi-arid landscapes.

Biomass production and yield efficiency functions. Low external input production systems usually incorporate a wide range of species and genotypes that serve a variety of production goals and are used for their resistance to diseases and pests as well as for the differential exploitation of microhabitats. The relative productivity and efficiency of these diverse agro-ecosystems (fish polycultures, mixed herds, intercrops, integrated agro-silvo-pastoral systems) have been quantified in terms of relative yield or energy efficiency of diverse units as compared with sole crops (Trenbath, 1974; Vandermeer, 1988; Leach, 1976). Results indicate that diversity rich agriculture is generally highly productive in terms of its use of energy and unit land area (or unit water volume). For example, the land equivalent ration (LER) of yields with intercrops in which mixtures include a legume species is usually significantly greater than outyield of sole crops (Vandermeer, 1990). The energy efficiency (ratio of energy output to energy input) of pig or poultry production in internally diverse agro-ecosystems can be up to 10 times higher than that of intensive pig and poultry farms based on genetically uniform single species reared with enormous subsidies of fossil fuels (Leach, 1976). Whilst the yield output per labour hour of the more intensive and uniform systems is extremely high (in the absence of the internalisation of social and environmental costs), the more agricultural biodiversity rich systems are generally efficient producers of significant amounts of biomass. This efficiency is largely a product of the systems' biological and structural complexity that increases the variety of functional linkages and synergies between different components of agricultural biodiversity.

Soil and water conservation functions. Soil, water and nutrient conservation have been improved with the use windbreaks, contour farming with appropriate border crops and cover crops in a wide range of agro-ecosystems. In France over 150 species of trees and shrubs are used for soil and moisture conservation, with different species mixtures planted as hedges and taller windbreaks in gardens, orchards, whole farms and the larger rural landscape (Soltner, 1984). In Sahelian countries of Africa windbreaks made up of Euphorbia tirucali, Parkinsonia aculeata, Opuntia tuna and Prosopis africana trees and shrubs help to conserve soil and moisture, and raise the yields of cereals which are grown between. In Mexico, contour lines are often planted with Agave americana to conserve soils and retain moisture whilst in southern Italy and Greece Opuntia tuna performs similar functions. Many of these plants are multiple purpose species yielding wood, edible fruit and nuts, fodder, refuges for natural enemies of pests, nitrogen biofixation and medicines in addition to their soil and water conservation functions.

Cover crops consist of plant species that are deliberately established after or intercropped with a main crop to serve various regenerative and conservation functions including soil and water conservation. Annual bluegrass, lana vetch, crimson clover, black medic, purple vetch and barley are some of the species recommended as cover crops for orchards and vineyards in California , USA (Finch and Sharp, 1976). The wide variety of management systems in high input-high output orchards and vineyards creates a demand for a diversity of cover crops. Grass species have fibrous root systems that make them particularly useful in building soil structure, providing erosion control, and improving water penetration. Legumes are not as effective as grasses in improving water penetration but they contribute nitrogen to the soil. Many cover crop options can be selected for soil and water conservation from a diversity of annually seeded winter growing grasses and legumes, summer annuals, perennial grasses and legumes and reseeding winter annual grasses and legumes.

In North America and Europe, living mulch systems can be an economic way for commercial soybean, corn and vegetable growers to reduce soil erosion and water loss, increase soil organic matter and keep yields constant in high input-high output agroecosystems (Miller and Bell, 1982). Legume species commonly used as living mulches include alfalfa, short white clover, hairy vetch and red clover.

Pest control functions. Agricultural biodiversity in the form of predators, parasitic wasps, micro-organisms plays a key role in controlling agricultural pests and diseases. For example, according to CAST (1999) more than 90% of potential crop insect pests are controlled by natural enemies that live in natural and semi-natural areas adjacent to farmlands. They have estimated the substitution of pesticides for natural pest control services at a cost of $54 billion per year.

Many methods of pest control, -both traditional and modern-, rely on biological diversity. The development of crop varieties and animal breeds that are resistant to specific pests and diseases selectively draws on the genetic diversity available in situ and in ex situ collections of germplasm (Browning, 1980). Genetic mixtures deployed in temperate and tropical agroecosystems can be effective in containing diseases in small grain crops (Browning and Frey, 1981; Leonard, 1969; Wolfe,1985) as well as insect outbreaks in cassava (Gold, 1987), corn (Power, 1988) and potato (Cantelo and Stanford; 1984) for example. There are also many documented experiences showing that insect pests tend to be less abundant and damaging in agroecosystems with higher plant diversity e.g. intercrops, polycultures, crop rotations, cover crops, mixed tree stands, mixtures of annual and perennial plants (Andow, 1991; Altieri, 1994). Depending on the pest species and the context, the plant diversity acts to reduce pest damage by interfering with the host seeking and reproductive behaviour of the pest, by enhancing the pests' natural enemy populations or by a combination of these processes. Judicious vegetation management within and around agroecosystems can thus enhance biological control or confer an overall resistance to pests and disease outbreaks.

Understanding how agricultural biodiversity directly or indirectly affects pest and disease dynamics is critical for the design of pest management at different scales. For instance, recent work in Javanese rice fields shows that there is an enormous diversity of anthropods, even in high input-high output agriculture. The arthropod communities are structured such that the dynamics of seasonal succession consistently lead to high levels of pest suppression, with little chance of outbreak. From the time that water first floods a farmer's field in preparation for planting, organic matter, -derived from residues from the previous crop cycle, organic waste in irrigation water, and algal growth-, provides the energy for an array of micro-organisms (bacteria and phytoplankton) and detritus-eating insects. The adults of the plankton-feeders (midges and mosquitoes) together with the detritus-feeders, provide a consistent and abundant source of alternative food for generalist predators very early in the season. As a result, pest mortality due to predation is high from the very earliest part of the season; hence, minimising the chance of damaging pest outbreaks (Settle et al, 1996). However, this intrinsic strength and stability of the rice agro-ecosystem is influenced by two main, large scale, external factors: 1) local and regional patterns of pesticide use, and 2) landscape effects--specifically, the spatial scale at which fields are synchronously planted, the duration and nature of fallow periods, degree of surrounding weedy or natural vegetation and existence of nearby ponds or other sanctuaries for natural enemies. This type of information on the functions of agricultural biodiversity in rice paddies provides the ecological basis for integrated pest control through careful management of the wider landscape and decisions on pesticide use.

Pollination and dispersal functions. There are more than 100,000 known pollinators (bees, butterflies, beetles, birds, flies, and bats). Pollination mediated by components of agricultural biodiversity is an important function in a variety of terrestrial agroecosystems (biotic pollination per se is poorly represented in aquatic ones). About half of all plant species, including food-producing crop species, are pollinated by animals. For example, the pollination of various fruit crops by bees and other insects is critical in mountain areas of Asia. In Nepal Apis cerana begins foraging at temperatures 5-7ºC lower than those that initiate Apis mellifera foraging. Managed crop pollination with a variety of bee species in different zones plays an important role in overall agricultural development (Partap and Partap, 1997). The benefits of pollination are also considerable in high input-high output agriculture: the economic value of pollination services in the United States is estimated in billions of dollars per year. Management practices that reduce the species or abundance of pollinators can result in less genetic variation in crops dependent on pollinator visits for reproduction, both in temperate and tropical agriculture. With a loss in pollinators, seed production declines and the vulnerability to pests and climatic change increases with the resulting loss of genetic diversity.

"Mobile link" species (i.e. animals necessary for the persistence of plant species that in turn support otherwise separate food webs) such as pollinators and seed dispersal agents may be critical to the maintenance of the species richness of tropical forest based agroecosystems and complex home gardens imitating the natural forests' architecture. Many species in tropical forests managed for food and agriculture depend on a small suite of frugivores for dispersing their seeds. Loss of these species of fruit eaters may adversely affect the long- term viability of many tree species important for food security. Reductions in genetic variability are likely to be high for plant species that are highly dependent on frugivory for seed dispersal.

Biological diversity conservation functions. There is no strict divide between "wild" and "domesticated" species important for food and livelihoods. Many wild plant species and populations that have been considered to be wild are in fact carefully nurtured by people (Gomez-Pompa and Kaus, 1992; Posey, 1999). A similar continuum exists for animal species that use agroecosystems as habitat, nesting grounds and food. Whilst not necessarily the subject of conscious management by herders or farmers, many wild species thrive in, or are dependent on, agroecosystems. In general the more structurally and biologically complex the agroecosystems, the more diverse the forms of wildlife. For example:

• The systems of shifting cultivation common in Asia have long been considered to be damaging to biological diversity in particular. However, given the opportunity, shifting cultivators preserve wild resources. Studies in Asia have concluded that most of the mature forests in this region are not virgin forests, but merely old forests that have reached a relatively stable dynamic state after some earlier clearing by human or natural means (Spencer, 1966; Wharton, 1968; Michon and de Foresta, 1995). Under traditional systems of shifting cultivation which speed up natural succession, wildlife flourishes, with elephants, wild cattle, deer, and wild pigs all feeding in the abandoned fields. Tigers, leopards and other predators are in turn attracted by the herbivores. Older fields contain a high proportion of fruit trees that attract primates, hornbills, squirrels and a variety of other animals.
• Long term research in the Lowland of west Poland shows that a mosaic of landscape structure of small cultivated fields, shelterbelts, meadows and small ponds helps maintain biological diversity (and many other functions such as enhanced water storage). Mammal, amphibian, reptile, insect diversity are enhanced and the number of bird species is positively correlated with the diversity index of the landscape (Ryszkowski, 1995).

Climate functions. Although agricultural and the atmosphere interact in many ways, the links between climate and weather, and agricultural biodiversity can be rather complex (Emanuel et al., 1985).

At the global scale, the distribution of individual plants and animals, vegetation and crops is conditioned by available climatic resources such as solar radiation, which controls the production potential, and by rainfall, which determines to what extent the radiant energy can actually be used by plants for their growth. Indeed, it is for these reasons that climatic classifications largely coincide with vegetation maps.

At the local scale, types of landscapes and vegetation, including crop and crop-vegetation mixes contribute towards modifying the local climates by directly affecting wind patterns, rates of evaporation, rainfall interception (effective rainfall), etc. This in turn conditions the development of vegetation and crop canopies which can be said to create their own microclimate, resulting from the interaction of plants with the general climate. Shelter belts, or the use or large tree belts to protect tropical plantation crops from cyclones, provide clear examples in which people and communities derive direct advantage from these landscape features.

Many examples demonstrate the benefits of maintaining minimum agrobiodiversity in the face of climate variability. Recent droughts in some southern African countries for example, have shown that mixes of local varieties planted over several weeks have the potential to better resist unusual patterns of rainfall variability (e.g. early-season drought) than some modern varieties planted on the "optimum dates". In fact, there appears to be a link between crop biodiversity and relatively low but regular production, one of the keys to food security.

Similarly, atmospheric pollution has been shown to interact with agro-ecosystem functions, both positively (nutrients, such as nitrates and sulphur) and negatively (toxic compound like tropospheric ozone and heavy metals). Given that the response to these substances varies enormously across the spectrum of species, they have the potential to modify patterns of biological diversity.

Agriculture also contributes towards the emission of some of the most significant "greenhouse" gases (in terms of global warming potential, GWP). Some studies have suggested for example, that increases in the area of permanently or quasi-permanently flooded rice cultivation account for a significant proportion of the increase in net methane emissions (Schutz et al, 1990). The increased specialisation of ruminant production based on high yielding breeds has also significantly contributed to global methane emissions (methane is produced by anaerobic digestion in animals). An extreme case would be the enhanced biogenic emissions of carbonylsulphide (Hofman, 1990) associated with increasing cultivation of high sulphur crops such as rape. Oxidation of carbonylsulphide in the stratosphere leads to the production of sulphate aerosols that influence the intensity of ultra violet radiation reaching the earth's surface (Charlson et al, 1987), potentially affecting the dynamic functions of agricultural biodiversity. Volatile organic compounds such as terpenes and isoprenes are produced and released into the atmosphere by many plant species (Tingy et al, 1991), especially in agroecosystems dominated by Mediterranean shrubs, eucalyptus and conifers. By influencing the oxidation capacity of the troposphere, these volatile compounds influence the abundance and distribution of trace gases such as ozone (Rennenberg, 1991). In almost all cases however, many of the these effects are marginal when compared with the climatic effects of land use change, including deforestation, which have until recently constituted one of the main non-industrial sources of carbon dioxide.

Functions in the water cycle. There are few experimental studies exploring the links between agricultural biodiversity and water. However, available evidence shows that agricultural biodiversity plays a crucial role in cycling water from the soil to the atmosphere and back. It also has measurable impacts on water quality. Agroecosystems with different species assemblages and plant architectures result in differences in the amount of precipitation intercepted, the proportion of precipitation converted to stem flow, and the proportion of precipitation that infiltrates the soil rather than running off. At the landscape level, the types, relative abundances and relative spatial locations of agro-ecosystem types affect the amount of water moving from one point to another. For example, conversion of vegetation within a watershed from forest or shrub land to less structurally and biologically complex grassland is known to influence stream flow out of the watershed, in both temperate and tropical systems.

At the functional group level, the root structure, phenology and physiology of different plant species important for food and agriculture have direct implications for the quantity and timing of water transfer to the atmosphere via evapotranspiration. Individual plant species differ in their resistance to water stress, their efficiency of water uptake from the soil, and so on. Genetic variations among crop varieties (differences in water use efficiency, stomatal resistance ...) also influence these processes. At the landscape level, evapotranspiration from agroecosystems can have an effect on relative humidity and microclimate downwind.

In both terrestrial and aquatic environments, the plant and animal components of agricultural biodiversity also function to alter water quality by performing various filtration, uptake and excretory processes. These functions all affect the composition and concentration of dissolved gases, solutes and particulates. Species level differences in physiology can positively or negatively affect water quality. However, in most cases a greater diversity of biological organisms (from microbes to fish and macrophytes) leads to a higher quality of water for human consumption and use.

The influence of agricultural biodiversity on landscape structure. A landscape is a heterogeneous area made up of a cluster of interacting ecosystems that is repeated in similar form throughout (Forman and Godron, 1986). The spatial layout between landscape elements together with the interactions and linkages between them determine the landscape's structure and functions. The many different species found in a landscape essential components of that landscape. By providing environmental services and functions (described above) agricultural biodiversity can have a profound influence on landscape structure. Through its positive or negative effects on agricultural biodiversity, human activity can transform whole landscapes over large areas. For example, many rural communities enrich their agricultural plots and forest fallows with valued perennial plants. Through such enrichment practices, successional vegetation can become a site for economic production as well as for ecological rehabilitation (Dubois, 1990). Each of the major tropical forest regions has many economic woody plants that have been managed, probably for millennia, in enriched fallows (Wood, 1993). In Vanuatu the natural composition of forests has been dramatically altered by centuries of itinerant gardening, favouring tree species that bear edible fruits and nuts (Weightman, 1989). Fallows have been (and still are) enriched with rattan in East Asia, rubber in Sumatra, Casuarina in Papua new Guinea, Gliricidia and peach palm in Central America, oil palm in West Africa, and edible fruits and nuts universally. Locally adapted enrichments have altered species composition and also directly influenced the structure of landscapes at different spatial scales.

The influence of agricultural biodiversity on landscape structure is partly determined by the social institutions that mediate the relationships between rural people and the environment, and partly by climate and edaphic factors. For example in the semi-arid landscapes used by pastoralists of Africa, there are high levels of spatial and temporal variability in fodder biomass production, highly variable rainfall and episodic chance events such as drought. In these non-equilibrium systems pastoralists have developed opportunistic management schemes to exploit the patchiness of the vegetation, learnt to avoid risks by moving herds and flocks to make best use of heterogeneous landscapes and diversified their livelihood activities. Pastoralists have rules and regulations which govern the use of water, pasture, animal movement and control of vegetation and trees. Management of agricultural biodiversity and the larger landscape is mediated by these local institutions. The local adaptive management of agricultural biodiversity enables people to cope with uncertainty and sustain the dynamic environmental processes that define and shape those landscapes. This is in stark contrast with the degradation that occurs under the centrally planned, standardised rangeland and livestock management schemes often based on erroneous concepts of carrying capacity and equilibrium ecology (Behnke et al, 1993; Scoones, 1994). New perspectives in ecology have challenged the conventional views of drylands in Africa as stable ecosystems subject to decline and desertification once carrying capacity is exceeded. Rangelands and pastoral landscapes are resilient and less prone to degradation and desertification than once thought. The new findings concord with the knowledge of many local livestock herders and emphasise how rangelands are subject to high degrees of uncertainty and ecological dynamics, characterised by sudden transitions rather than slow and predictable change.

Specific components of agricultural biodiversity are often directly implicated in the processes that structure agroecosystems at different temporal and geographical scales (from small farm plots to whole water/landscapes). Even highly complex landscapes like tropical irrigated rice or forests in the savannah transition zone of West Africa, are apparently structured by a very few key variables (cf. Settle et al, 1996; Fairhead and Leach, 1996). Research over the past 20 years in applied ecology of managed systems shows that ecosystem and landscape dynamics tend to be organised around a small number of nested cycles, each driven by a few dominant variables (Gunderson et al, 1995; Holling, 1993; Holling et al, 1995).

A small number of plant, animal, and abiotic processes structure biomes over scales from days and centimetres to millennia and thousands of kilometres. Individual plant and biogeochemical processes dominate at fine, fast scales; animal and abiotic processes of mesoscale disturbance dominate at intermediate scales; and geomorphological ones dominate at coarse, slow scales ... the physical architecture and the speed of variables are organised into distinct clusters, each of which is controlled by one small set of structuring processes. These processes organise behaviour as a nested hierarchy of cycles of slow production and growth alternating with fast disturbance and renewal (Gunderson et al, 1995).

Identifying and understanding the dynamics of these "structuring variables" provides a practical basis for sustainable agriculture and landscape management.

In addition to its direct contributions to rural livelihoods (see section (i)), agricultural biodiversity may generate other rural development opportunities through eco-tourism and a variety of income generating schemes. Many humanised landscapes in Europe, South America, Australia and the Asia-Pacific regions are increasingly valued for aesthetic and historical reasons. For example, throughout the Asia-Pacific region mountainous terrain has, over the centuries, been shaped into landscapes of terraced pond fields for the cultivation principally of rice, but also of taro and other crops. In Europe, low input, extensive farming systems such as the Dehesas in the Iberian peninsula of Spain cover some two million hectares. Dehesa systems are open savannah like woodlands used as pastures, with sclerophyllous trees, mainly Quercus rotundifolia Lam., and a therophytic herb layer (MAB, 1989). Dehesas are home to many endangered species of wildlife such as the Iberian lynx, the golden eagle, the little bustard and the Egyptian vulture (Pineda and Montalvo, 1995).

These landscapes exist both as archaeological (i.e. preserved) sites and as living landscapes, which continue to be used and maintained by the people who created them. The conservation of these cultural landscapes is considered important by a growing number of stakeholders. For example, many low external input agroecosystems in Europe are valued by urban populations ready to pay for the experience of a holiday in rural areas (IEEP and WWF, 1994). At a global level, the intrinsic value of THESE cultural landscapes, and what they can teach about enduring systems of human-nature interaction, has led to a strategy within which the identification, evaluation and conservation of specific regional landscape types are to be considered within the framework of the World Heritage Convention (UNESCO, 1996). The ecotourism potential of these cultural landscapes is viewed as potentially important for rural development and local employment creation, both in the developed and developing countries.

However, recent evidence suggests that the potential of eco-tourism can only be realised under certain conditions. As is often the case for classical tourism, eco-tourism schemes tend not to be integrated with other sectors of the national or regional economy; and only a fraction of earnings generated actually reach or remain in the rural areas (Honey, 1999; Koch, 1997; Speelman 1991). More importantly, the majority of the rural population is frequently bypassed economically even where some earnings remain in the tourist location, as they are used up by the related administration or appropriated by local élites and business people. At the same time, local livelihood sources and cultures are negatively affected in nearly all cases. Generating economic benefits and fostering equitable rural development is only feasible when many wide-ranging reforms,- such as restoration of land and water rights to local communities, support for new forms of tenure and rights of usufruct, strengthening of local groups and institutions, investment in technical and managerial skills and mandatory impact assessments of all ecotourism schemes-, are carried out (Koch, 1997). The necessary structural political and economic changes along these lines are difficult in many developing and developed countries.

Another potential engine for rural development is the exploration, extraction and screening of biological diversity and indigenous knowledge for commercially valuable genetic and biochemical resources (biodiversity prospecting or bioprospecting) (Reid et al, 1993). A detailed treatment of the economics of bioprospecting is beyond the scope of this paper. However, it may be noted here that despite frequent mention of benefit sharing agreements in commercial contracts between bioprospecting agents and sovereign states, the specific terms of benefit sharing are strictly confidential. Available evidence indicates that benefits shared with countries in which collections took place represent a small fraction of the annual Research and Development budget of the corporations involved (RAFI, 1994; Pimbert, 1997; UNDP, 1994). Moreover, indigenous and local people receive only a minuscule proportion of the profits generated from sales of products that embody their knowledge and resources. For example, one study has estimated that less than 0.001 per cent of the market value of plant based medicines has been returned to local and indigenous peoples from whom much of the original knowledge came (Posey and Dutfield, 1996). And while various codes of conduct and guidelines have been developed to ensure greater equity, compensation and fair sharing of benefits between bioprospecting companies and local communities (e.g., FAO, 193; WWF, UNESCO and Kew Gardens in Cunningham, 1993b; Shelton, 1995), none are internationally legally binding.

Further opportunities for rural development hinge on creating local businesses and products that sustainably use agricultural biodiversity and add value to it in the context of more localised economies. In a growing number of rural areas in Europe, North America, Australia, Japan and New Zealand the diversity of local plants and animals is being harnessed for sustainable economic development. In south east France, the regional genetic heritage program of the Provence-Alpes-Cotes d'Azur involves a wide range of actors spread across six administrative departments,- about 31,500 square kilometres of very diverse ecosystems. Ways and means of reintegrating locally adapted, traditional animal breeds (sheep, goats, cattle and bees) and crop varieties (fruit trees, fodder plants and cereals) are being explored to generate local products, jobs, income and environmental care (PAGE PACA, 1990). Similar initiatives are reinvigorating local economies and employment in the Willapa watershed of the Pacific North West (USA). The Willapa watershed includes 275,000 hectares on the coast of Washington state and is rich in agricultural biodiversity: oysters, clams, sturgeon, crabs, salmon and dense forests. With the support of the Ford Foundation and a Chicago based community bank a range of local businesses have been set up to add value to this local agricultural biodiversity. For example, Willapa oysters are now marketed locally rather than shipped out wholesale, alder is harvested from secondary forests for high quality wood products, fish and crab are marketed with the north-west image of wholesome foods, cranberry growers produce a wide range of products retaining more of the value added from food processing within the watershed (Maughan, 1995).

These forms of endogenous rural development seek to create viable and locally controlled economic activities based on locally adapted agricultural biodiversity, knowledge, skills and negotiated partnerships between civil society, government and the private sector. Initiatives to reclaim diversity for rural development often focus on regenerating local food systems and economies based on comprehensive definitions of well being and wealth, both in developed (CES, 1999; Pretty, 1997) and developing countries (Women Sanghams et al, 1999).

These examples together with the recent "discovery" of the potential of cultural landscapes and the creativity of their inhabitants illustrate a more fundamental point. Agricultural biodiversity, together with the local knowledge, institutions and management practices associated with it, may provide a robust foundation for development in many different economic and ecological settings. Understanding the forces that have neglected or undermined the values and functions of agricultural biodiversity can help identigy ways forward.

Local and indigenous ways of knowing, valuing and organising the world have been frequently brushed aside by so called "modern" technical knowledge. Both colonial and post-colonial administrations in Africa, Asia and the Americas, as well as governments in the newly emerging nation states of Europe, have often either neglected or undermined local management systems. These systems were generally sensitive to the needs of local people and often enhanced their capacity to adapt to dynamic social and ecological circumstances. In addition to ignoring local knowledge and skills, many modernising interventions have superseded or substituted existing formal and informal institutions that were central for the sustainable management of agricultural biodiversity. In both terrestrial and aquatic landscapes, these l ocal groups enforce rules, incentives and penalties for eliciting behaviour conducive to rational and effective resource conservation and use. For as long as people have engaged in livelihoods pursuits, they have worked together on resource management, labour sharing, marketing and many other activities that would be too costly, or impossible, if done alone. Local groups and indigenous institutions have always been important in facilitating collective action and co-ordinated management of agricultural biodiversity at different spatial scales. Indigenous peoples resource management institutions provide striking examples of active conservation and sustainable use. These institutions include rules about use of biological resources and acceptable distribution of benefits, definitions of rights and responsibilities, means by which tenure is determined, conflict resolution mechanisms and methods of enforcing rules, cultural sanctions and beliefs (Alcorn, 1994).

This neglect of human ingenuity and diversity continues today and ultimately reinforces the dominant model of development based on uniformity, centralisation and control (Scott, 1998).

One of the most fundamental causes of agricultural biodiversity loss, both past and present, is the active promotion and spread of the blueprint approach to development. Typical expressions of this are industrial agriculture and the closely related Green Revolution. The blueprint paradigm is also reflected in many contemporary forest, fishery and rangeland development. This approach to food and fibre production focuses on maximising commercially important yields and productivity through the use of monoculture systems and uniform technologies, including high yielding seeds and animal breeds, agrochemicals, irrigation, mechandised equipment and large infrastructure developments. The methods and means deployed for production largely originated in the West where money and trained personnel ensure that technologies work and that laws are enforced to secure management objectives. During and after the colonial period, these technologies, and the values associated with them, were often "exported" from the North to the South (Table 2).

(adapted from David Korten and Pimbert and Pretty, 1995)

Managerially, the blueprint approach fits the type of organisations with clear and fixed definitions of roles, procedures and methods, hierarchical authority, punitive management style and inhibited lateral communications. These organisational structures are often better suited to routine activities and do not cope well with fast changing circumstances. The main actors in these organisations are normal professionals who are concerned not just with research, but also with action. Normal professionals are found in research institutes and universities as well as in international and national organisations where most of them work in specialised departments of government (forestry, fisheries, agriculture, health, wildlife conservation, pastoral administration ...). Despite some notable exceptions, the thinking, values, methods and behaviour dominant in their profession or discipline tends to be stable and conservative. Lastly, normal professionalism generally "values and rewards "first" biases which are urban, industrial, high technology, male, quantifying, and concerned with things and with the needs and interests of the rich" (Chambers, 1993).

This blueprint approach to the management of agricultural biodiversity is often supported, subsidised and defended by an elaborate institutional structure,- including many international donors and development agencies, international and national research institutions and national governments. Numerous policies, -ranging from general agricultural development policies to pricing and credit schemes-, directly or indirectly influence biological diversity in livestock production, agriculture, forestry and fisheries. The most influential are incentive policies (e.g. subsidies for agrochemical inputs, extension programs, credit policies and marketing standards) that support the adoption of capital and energy intensive industrial inputs and technologies. For example, extension programs in many countries have mandated the adoption of uniform varieties and the elimination of diversity. Policy incentives for people to clear forested land and establish farms in order to gain tenure in Brazil, Costa Rica and Indonesia have contributed to increases in food production but they have also induced biological diversity losses and unsustainable land use.

Private companies, particularly transnational corporations that market agricultural inputs and process food and fibres, exert a strong influence on the type of agricultural biodiversity used in production. During the 1940s and 1950s, research and development (R&D) capabilities started to move out of public institutions into the hands of the private sector. By the late 1990's, the pace of corporate concentration in the food, agrochemicals, pharmaceuticals, seeds and animal veterinary products accelerated. In 1998, the top ten seed companies controlled approximately 32% of the US $23 billion seed trade world-wide whilst the top ten animal health firms control about 60% of the US $17 billion animal health industry. Over 85% of the US$ 31 billion agrochemical market is controlled by less than eight corporations. With the help of new biotechnologies (e.g. gene splicing, enzyme technology) traditional boundaries between pharmaceuticals, agribusiness, biotechnology, food, chemicals, cosmetics and the energy sector are becoming increasingly blurred. Biology and the use of the diversity offered by plant, animal and microbial genetic resources is the common denominator (Baumann et al, 1996; RAFI, 1999). In many countries, including in the OECD countries, the R&D budget of these corporations dwarfs that of public sector research. As a result, corporate priorities and industrial strategies are increasingly reflected in research, development and distribution of seeds, livestock and other technologies that directly affect agricultural biodiversity. Evidence suggests that the corporate quest for commercial profits and control over production has promoted more, rather than less, genetic and ecological uniformity in agroecosystems. For example, new biotechnologies such as pesticide resistant crops and seeds engineered to terminate germination after one growing season constitute potentially serious threats for agricultural biodiversity, at different temporal and spatial scales (Ho, 1997; UNEP-CBD-SBSTTA, 1999).

Concerns are increasingly voiced regarding the level of influence some corporations have in determining which areas of scientific knowledge are developed, and for whom. The private sector invariably privileges planning and investment directed at short-term returns rather than longer-term ones. Over time for example, a range of more reductionist scientific perspectives and techniques have been selectively favoured over whole ecosystem science approaches, basic taxonomic work, population biology, landscape ecology and understandings of human-environment interactions based on plurial and interdisciplinary perspectives. This seriously undermines the long term ability of society to design sustainable agroecosystems based on a functional agricultural biodiversity that reduces dependence on suppliers of off farm inputs. Moreover, market dominance combined with monopoly patents gives the life industry unprecedented control over the products and processes of agricultural biodiversity,-the biological basis of food and livelihood security.

A significant cause of agricultural biodiversity loss is linked with the inequitable access to, and control over, land, water, trees and genetic resources. Denying rights of access and resource use to local people severely reduces their incentive to conserve resources and undermines local livelihood security. Both colonial and many national governments have a long history of denying the rights of indigenous peoples and rural communities over their ancestral lands and the resources contained therein. Denial of access, insecure tenure and rights of usufruct over the agricultural biodiversity contained in protected areas is one of the major factors undermining both conservation and development objectives (Ghimire and Pimbert, 1997). The same is true for forests, wetlands, farms, rangelands and common property lands outside of protected area networks.

Recognition of anthropogenic landscapes and "wild" species moulded by human agency has important implications for ownership, and consequently rights over access and use of biological resources. However, Western concepts of private property do not recognise the intellectual contributions and informal innovations of indigenous and rural peoples who have modified, conserved and managed so called "wild" species and landscapes (Crucible, 1994).

Inequities in access and control over genetic resources of domesticated plant and animals have also contributed to the erosion of diversity and the exploitation or displacement of local knowledge. Although most genetic resources originate from developing countries, transnational companies and northern institutions have captured a larger share of the benefits from using such resources in breeding programs and new natural product development. Legal means such as industrial patents and other intellectual property rights allow companies and northern institutions to maintain disproportionate control over the knowledge, genetic resources and benefits associated with agricultural biodiversity (GRAIN, 1998,1999; Tansey, 1999). In contrast, the local communities and farmers who originally nurtured this genetic diversity have generally not been recognised nor compensated for their innovations.

Even though agricultural biodiversity has many values and performs many functions, it is undervalued or even ignored in conventional economic assessments. This is partly because the multiple ecological functions of agricultural biodiversity are difficult to value in economic terms. Moreover, the few economic analyses of biological diversity conducted so far have essentially focused on global values and foreign exchange elements and very little on the household use values of, for example," wild" foods and medicines (Scoones et al, 1992; IIED, 1995). Simple economic valuations based on direct use values (for consumption or sale) (see Pearce et al, 1989) have often been misleading and too reductionist to provide a sound decision making basis for policy makers and land use planners. The economic and social values of much of the biological diversity that nurtures rural people have been ignored or underperceived by outside professionals. This has biased conventional resource planning in favour of major food crops and species of commercial importance for urban centres.

The expansion of global markets and recent patterns of trade liberalisation tend to have a homogenising effect on agricultural biodiversity by standardising food production and consumption. Global markets usually demand uniform foods that are increasingly processed and sold by transnational corporations, and are geared to meet the food desires of relatively wealthy, urban based consumers- both in developing and developed countries. In turn, these market pressures often force farmers world-wide to comply with those demands for uniformity. The policies for harmonisation of standards that accompany the globalisation of markets are also powerful forces undermining efforts for the sustainable use of local agricultural biodiversity and local adaptations.

The expansion of human populations and large migrations are often partly responsible for agricultural biodiversity losses in new "frontier" areas such as forests, coastal zones, mangroves and grasslands. Whilst in some contexts population growth per se is clearly responsible for agricultural biodiversity loss, there are many situations in which inequitable land tenure, forest concession policies, colonisation programs, land use and fishing policies are the root causes behind the biological diversity loss induced by growth in human numbers or migrations. Conversely, more people can mean more care for the environment and enhanced agricultural biodiversity under certain conditions, as shown by research in Sierra Leone (Richards, 1993) and Kenya (Tiffen et al, 1994).

A recent FAO-SCBD International Technical Workshop, held in December 1998, proposed a series of actions necessary for sustaining agricultural biodiversity and agro-ecosystem functions (Box 4). This concluding section endorses and complements the proposed actions, and presents additional recommendations which expand on the results of the workshop and flow on from the analysis of the root causes of agricultural biodiversity loss outlined above. Taken together, these recommendations and action points offer a contribution to the formulation of a comprehensive policy framework for national governments and international organisations.

Broadly speaking, there are two alternative scenarios for the management of agricultural biodiversity (Table 2). The dominant blueprint approach to development has been identified as a major underlying cause of agricultural biodiversity loss. Nevertheless, national governments, the private sector and civil society may choose to stay within this paradigm and reform some of its less acceptable elements in their quest for more sustainable agriculture and land use. In sharp contrast, the learning process approach focuses on reversals from the norm and structural change, rather than systemic adjustments within well defined and often narrow boundary conditions. Discussions around these alternative scenarios are inevitably emotionally charged. The issues at stake go beyond purely technical matters and include the fundamental human right to food, the right to a healthy environment as well as the political economy of who gains and who loses. These are difficult political questions that require contradictory debate within society and negotiated solutions involving all stakeholders. Answers are not the prerogative of experts and technical bodies alone. All the latter can do is to facilitate public debate by highlighting possible policy options and technical choices. Whilst some policy recommendations presented below may be relevant for both scenarios, many have been framed within the scenario that departs from dominant values and practices.

Knowledge about agricultural biodiversity and the processes enhancing or eroding it is the basis of national and international policy making and determines which kinds of management regimes prevail. However, much is uncertain and unknown about the structure and multiple functions of agricultural biodiversity. There are huge gaps in knowledge on the number of species living on Earth: estimates of total species numbers vary between 5 and 30 million and a mere 1.6 million species have been described to date. Knowledge on the functions of biodiversity, -synergies and complementarities, interactions within agro-ecosystems, ecological processes within soils and interactions with the atmosphere and water-, are rudimentary. An emerging picture describes the structure and functions of agricultural biodiversity in terms of variability, sudden as well as slow change, complexity and indeterminancy at different spatial and temporal scales. But there are considerable uncertainties and on-going scientific debates on the actual functioning and dynamics of ecosystems and landscapes (e.g. equilibrium versus dis-equilibrium ecology, views on succession, stability-diversity relationships, carrying capacity ...).

Major investments are therefore needed to improve and expand our knowledge about agricultural biodiversity and its functions. Historical analysis, the use of complementary methods from the social and natural sciences and the knowledge of local resource users are all clearly needed to identify and properly explain the structure and functions of agricultural biodiversity at different scales. There are, after all, differently situated forms of knowledge about agricultural biodiversity, and each is partial and incomplete. Participatory learning and action is needed to bring together these multiple and separate realities, combining the strengths of modern science with local knowledge. There is indeed a strong rationale for democratising science in an age of uncertainty by directly involving "extended peer communities" (Funtowicz and Ravetz, 1993) that include farmers, herders, forest dwellers, fisherfolk and other rural people in the production and sharing of knowledge on agricultural biodiversity and its many functions (Batterbury, et al, 1997; Irwin, 1995; Kloppenburg, 1991; MacRae et al, 1989; Pimbert, 1994).

• Provide adequate fiscal and administrative support for basic taxonomic work and inventories within and among plant, animal, microbial species and varieties
• Provide support for studies aimed at understanding the dynamic functions of agricultural biodiversity at different spatial and temporal scales, with a particular focus on the roles of soil biodiversity, pollinators, pest predators and the processes of landscape transformation
• Develop and use methods and indicators to monitor the impacts of agricultural extensification and intensification on biological diversity and local livelihoods, and promote their application
• Provide support and high rewards for studies on the functions of agricultural biodiversity that combine indigenous with scientific knowledge, using innovative participatory and complementary methodologies to do basic research in an applied way
• Diversify the governance and the membership of budget allocation committees of public sector planning and research institutes to include representatives of farmer, pastoralist, forest and fishing communities, organisations and federations, at both local and national levels
• Establish procedures to ensure transparency, equity and accountability in the allocation of research funds and dissemination of new knowledge

Agricultural biodiversity performs vital functions in agriculture, land and water use. The diversity of plants, animals and micro-organisms is essential for maintaining the productivity and sustainability of farm crops and animals, managed forests and rangelands, aquaculture and fisheries. Future global food security is dependent on harnessing and sustaining agricultural biodiversity and its many functions, from the farm plot to the landscape level.

In both low external input and high input agriculture, the goals of sustainability, productivity and equity may best be met through agro-ecosystem designs that enhance functional diversity at the genetic, species and landscape levels. A central challenge across the whole range of agroecosystems is to find alternatives to the input substitution approach and future dependence on costly biotechnology packages. This can be achieved through an agro-ecological approach that seeks to break the monoculture structure and dependence on suppliers of off farm inputs through the design of integrated agroecosystems. By assembling a functional biological diversity within and around agroecosystems, it is possible to encourage synergism's that subsidise agro-ecosystem processes by providing ecological services, the recycling of nutrients and the enhancement of natural enemies of pests as well as provide diverse, quality foods and other farm products.

The current emphasis on genetic engineering must be balanced by higher level approaches that build on agro-ecology, landscape ecology as well as social and biological diversity. National sovereignty and food security ultimately depend on a wide choice of agricultural technologies and development options.

• Establish and implement national policies to support agro-ecological approaches that enhance agricultural biodiversity in food and fibre production through integrated pest, crop, nutrient and soil management as well as land use planning. The policy framework should ensure political commitment, educational and institutional capacities as well as incentives for enhancing agricultural biodiversity and its functions in agriculture and land use
• Provide fiscal and administrative support for studies that investigate ways to maintain and enhance the utilisation of agricultural biodiversity in crop and animal production and in different kinds of agroecosystems, particularly high yielding and intensive commercial production systems
• Promote development on the basis of locally adapted genetic material. Strengthen in particular the capacity to develop new crop varieties and animal breeds that are specifically adapted to local environments. Increase the range of genetic diversity available to farmers
• Broaden the use of genetic diversity to protect crops and animal breeds against pest and weather problems by introducing multiple genetic systems for coping with stresses and also by deploying functional genetic mixtures and multilines where appropriate
• Broaden the use of species diversity into functional designs for agroecosystems that sponsor more of their own soil fertility, crop protection, pollination and water management (agroforestry systems, multiple cropping, fish polycultures…).
• Plan and manage rural landscapes to sustain biological diversity and ecosystem services. Where appropriate, maintain hedgerows, windbreaks and mangrove strips, leave tracts of land in native habitat, plant a diversity of crops, encourage pastoral activities, mixed species forestry and aquaculture. Maximise the use of resources internal to the landscape whilst closing nutrient cycles by integrating production with local needs and markets situated within or near the managed landscape. Apply the same principles for urban landscapes where food and fibre are produced.

Variation within and among agroecosystems is enormous. Daily, seasonal and longer term changes in the spatial structure of agricultural biodiversity are apparent at the broad landscape level right down to small plots of cultivated land (Box 5). These spatio-temporal dynamics have major implications for the way agricultural biodiversity is managed, -how, by whom and for what purpose.

Uncertainty, spatial variability and complex non-equilibrium and non linear ecological dynamics emphasise the need for flexible responses, mobility and local level adaptive resource management in which local users of agricultural biodiversity are central actors in analysis, planning, negotiations and action (Gunderson et al, 1995; Pretty and Scoones, 1995; Swift, 1999). This calls for far greater appreciation of local farming practices and knowledge used by rural people to manage agricultural biodiversity in forests, wetlands, fields, rangelands, coastal zones and freshwater systems. It frequently suggest new practical avenues for technical support in which land users' own priorities, knowledge, perspectives, institutions, practices and indicators gain validity (Leach and Mearns, 1996; Netting, 1993; Pimbert and Pretty, 1998; Posey, 1999; Richards, 1985).

• Carry out administrative tasks, land use planning, agricultural research and development as near to the level of actual users of resources or beneficiaries of administration as is compatible with efficiency and accountability
• Ensure flexibility and diversity in institutional and organisational design to enable government administration and services to track appropriately the dynamic changes which occur in agroecosystems and the functions of agricultural biodiversity at different time and spatial scales.
• Educate policy makers, professionals and the public (including the bearers of local knowledge) about the value of local and indigenous knowledge and management systems in sustaining agricultural biodiversity and its many functions
• Strengthen local groups and institutions by devolving resources and removing administrative or legal hurdles to local planning and action. Support the development of local institutions for common property resources and the equitable sharing of benefits from their utilisation
• Identify and support a mediator for conflict resolution and an arbiter of last resort; guaranteeing a level legal playing field and equality of advocacy in disputes, both within and between local groups as well as between local groups and powerful external interests. Of particular importance in this connection are government policies and actions that explicitly prevent discrimination on the basis of differences in gender, ethnic orgin and wealth.

From the outset, the definition of what agricultural biodiversity is to be conserved, how it should be managed and for whom should be based on interactive dialogue to understand how local livelihoods are constructed and people's own definitions of well being. Most professionals have tended to project their own categories and priorities onto local people and landscape management. In particular, their views of the realities of the poor, and what should be done, have generally been constructed from a distance. Household livelihood strategies often involve different members in diverse activities and sources of support at different times of the year. Many of these, like collecting wild foods and medicine, home gardening, common property resources, share-rearing livestock and stinting are largely unseen by outside professionals.

Agricultural Research and Development and land use planning should start with enabling local people, especially the poor, to conduct their own analysis and define their own priorities. This methodological orientation is absolutely essential to meet the goals of equity, sustainability, productivity and accountability. In that context, dialogue, negotiation, bargaining, conflict resolution and joint management agreements are all integral parts of a long term participatory process which continues well after the initial appraisal and planning phases into monitoring and evaluation. This implies the adoption of a learning process approach in the management of agricultural biodiversity and its functions (Table 2). It also calls for a new professionalism with new concepts, values, participatory methodologies and behaviour (Pretty and Chambers, 1993).

• Ensure public participation of women and men (particularly farmer, herder, fisherfolk and forest dweller involvement) in the development of land use and agricultural policies and in the generation of technologies
• Ensure inclusive equitable representation (gender, class, ethnic origin, age) in the participatory activities and process
• Provide capacity building for technical and scientific personnel to foster those participatory skills, attitudes and behaviour needed to learn from farmers and rural people (mutual listening, respect, gender sensitivity as well as methods for participatory learning and action)
• Provide institutional space and incentives for professionals to understand social and cultural complexity as well as agro-ecological diversity
• Support joint problem-solving among local people, scientists and/or extension workers and the development of negotiated participatory research agendas and resource management agreements, using local criteria and indicators as well as those of outside professionals and their organisations
• Support the participatory monitoring and evaluation of national policies, land use plans, food and fibre production technologies by building on the perspectives of all social actors. Encourage the use of gender desegregated and socially differentiated local indicators and criteria in monitoring and evaluation as well as in guiding subsequent technical support, policy changes and allocation of scarce resources for agricultural biodiversity management.

Local adaptive management of agricultural biodiversity and large-scale participation do not mean that state bureaucracies and other external organisations have no role. But they do challenge bureaucracies to assume different roles and responsibilities. In particular, existing bureaucracies and professionals will often need to shift from being project implementers to new roles that facilitate local people's analysis, planning, action, monitoring and evaluation. The whole process should lead to local institution building or strengthening, so enhancing the capacity of people to take action on their own. Appropriate partnerships and co-management agreements between states, the private sector and rural communities are also required through new legislation, policies, institutional linkages and processes.

However, the adoption of a participatory culture and changes in professional attitudes and behaviour are unlikely to automatically follow when new methods are adopted. Training of agency personnel in participatory principles, concepts and methods must be viewed as part of a larger process of reorienting institutional policies, organisational cultures, procedures, financial management practices, reporting systems, supervisory methods, reward systems and norms (Absalom et al, 1995; IIED-IDS, 1999; Thompson, 1995). In both government departments and non governmental organisations, the challenge for top and middle management is to design appropriate institutional mechanisms and rewards to encourage the spread of participatory methods within the organisation. Without this support from the top, it is unlikely that participatory approaches that enhance local capacities and innovation will become core professional activities.

An important challenge concerns the creation of new relationships between local communities and their representative organisations, government agencies, research institutions and transnational corporations. Capitalising on the energy, resource efficiency and dynamism of the private sector constitutes a significant opportunity for increasing the performance of the agricultural sector and environmental sustainability.

• Encourage shifts from hierarchical and rigidly bureaucratic structures to "flat", flexible and responsive organisations
• Ensure that senior and middle management positions are occupied by competent facilitators of organisational change, with the vision, commitment and ability to reverse gender and other discriminatory biases in the ideologies, disciplines and practices animating an organisation.
• Promote and reward management that is consultative and participatory rather than verticalist and efficiency led. Establish incentive and accountability systems that are equitable for women and men
• Provide incentives and high rewards for staff to experiment, take initiatives and acknowledge errors as a way of learning by doing and engaging with the diverse local realities of farming, fishing and pastoral societies
• Redesign practical arrangements, the use of space and time within the workplace to meet the diverse needs of women, men and older staff as well as their new professional obligations to work more closely with farmers and other stakeholders (time tables, career paths, working hours, provision of paternity and maternity leave, childcare provisions, mini sabbaticals, promotion criteria ...)
• Support the creation of mechanisms of communication and collaboration between the private sector, and in particular, major corporations active in the agricultural sector, and other kinds of institutions and groups

There is a need to provide a legal framework within which a devolved management of agricultural biodiversity can operate effectively, especially in respect of resource tenure. The legitimacy of rural peoples’ claims to tenure and rights to agricultural biodiversity are made more apparent as landscapes are re-interpreted as the product of social and ecological histories. If landscapes, species and genetically distinct populations have been moulded or modified by human presence and actions, local communities may claim special rights of access, decision, control and property over them. These findings support a rights based approach to the participatory management of biological diversity important for food, agriculture and livelihoods (Pimbert and Pretty, 1998; Posey, 1999). They also have major implications for national policies on the sharing of benefits derived from the use of landscapes, agricultural biodiversity and its end products. Guaranteeing the secular right of farmers' to save and re-use seeds and livestock progeny is crucial in this connection. Failure to enshrine these rights in national legislation and policy practice may lead to inequitable benefit sharing schemes and conflicts that could undermine the sustainable management of agricultural biodiversity and food security.

• Reform policies and laws on rights of access, use and control over land, trees, water and genetic resources to ensure that farmer's and indigenous peoples' rights are protected as a basis for equitable benefit sharing arrangements
• Ensure that intellectual property rights over genetic resources currently re-negotiated within the TRIPs agreement of the World Trade Organisation do not undermine the objectives of conservation and sustainable use mandated by the Convention on Biological Diversity and ongoing negotiations on the International Undertaking on Plant Genetic Resources

Economic instruments are key to sustaining agricultural biodiversity and its multiple functions. Trade policies, markets, subsidies and economic incentives must reinforce the objectives of the Convention on Biological Diversity rather than contradict or actively undermine them. A multilevel and systemic approach to economic transformation will often be needed to reform trade, taxation and public spending aimed at sustaining agricultural biodiversity and its multiple functions (Robertson, 1998; http://attac.org, 1999).

• Reform international and national trade-related policies that contribute to the loss of agricultural biodiversity and develop trade rules that promote social and biological diversity by regenerating local economies and food systems
• Eliminate policies and economic incentives that contribute to the erosion of agricultural biodiversity and its functions, particularly subsidies for High Yielding Varieties, pesticides and fertilisers; credit policies that require the use of such inputs and monocultures; variety release and seed certification legislation that hinder the utilisation of diverse genetic material through their requirements for distinctiveness, uniformity and stability; pricing and tax policies that favour genetically and ecologically uniform production systems
• Assess the economic benefits of agricultural biodiversity (domesticated and managed wild diversity) in a more comprehensive manner to improve the decision making basis for policy makers, land use planners and agricultural R&D. Economic benefits based on the use of « wild » and domesticated agricultural biodiversity should be situated and evaluated in a total livelihood context
• Establish flexibility in marketing standards to allow food distributors and retailers to diversify varieties of produce and reduce wasteful cosmetic standards for foods in markets
• Implement anti-trust laws and other regulations that limit or prevent unfair market domination by corporations that sell seeds, animal embryos, agrochemicals, veterinary products and biotechnologies or/and process and distribute food and fibres
• Restructure the tax system to encourage employment and enhance agricultural biodiversity in the entire food and fibre production-distribution chain. Ensure greater public sector spending and fairness within the food system.

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