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Chapter 5

Environmental and developmental constraints

The use and development potential of wild species in farm households is subject to a series of constraints. Many of them derive from the very nature of wild resources, while others arise from social, economic, legal or institutional factors.


Wild plants, by definition, grow in natural or semi-natural ecosystems in different biomes around the world. All these biomes have been greatly affected and modified by human activities such as the conversion of forested land to other uses (agriculture, pasture, urbanization, industrial and other uses) and the almost universal phenomenon of ecosystem fragmentation whereby activities such as agricultural development, forestry or urbanization remove large proportions of the natural ecosystem and replace them with a greatly modified matrix, within which small remnants of the native ecosystem remain. The current scale of human impacts on biodiversity is unprecedented and is increasing dramatically. Humans have transformed, modified, managed or utilized about half the land surface, and it is difficult to find any areas that can be described as pristine, undisturbed or virgin.

Species under threat

One of the consequences of habitat loss, fragmentation or degradation is the large number of wild species that are threatened with local or total extinction, including many that are used by farm households. The numbers are difficult to ascertain, but the 1997 IUCN red list of threatened plants (IUCN, 1998) lists 33 370 that are threatened to some degree, representing approximately 11 percent of described species. While some species are under imminent risk of total extinction, the threat of extinction much more commonly pertains to local populations of species. Such local extinctions are what concern farm households, not the overall situation of the species concerned, since the household's area of operations for agriculture and wild harvesting is usually circumscribed. Moreover, local populations are adapted to the particular environment, and substitutes are often not acceptable or not as well adapted to local conditions.

It follows that local farmers should make efforts to conserve germplasm of the wild species that they use in their home gardens and at the same time adopt responsible policies for wild harvesting, whether the material collected is for their own use or for third parties such as pharmaceutical companies or their representatives (see Chapter 4), so that the resources continue to be available for present and future use. Incentives to conserve the resources should be built into agreements such as those on bioprospecting, although, as already noted in Chapter 4, these do not fully recognize the role of local collectors and their special knowledge. The State and extension workers should encourage local collectors to negotiate agreements with manufacturing and processing companies or their agents that safeguard their interests.

Overexploitation and overharvesting

A characteristic pattern of resource exploitation by many traditional farm communities is the radial depletion of woody plants surrounding villages or settlements, especially plants used for fuelwood or for medicinal purposes. This pattern of depletion can have serious social effects, especially on the poorest members of the community, who are forced to walk further or to pay more for fuelwood, plant materials for construction and craft work and medicinal plants.

The increase in the number of urban dwellers who still rely on traditional plant-based remedies has added to the pressure on wild resources and has led several species to face a serious risk of population loss and genetic erosion through unsustainable harvesting practices such as decortication.

In addition, many medicinal plants are reported to be at risk as a result of unethical practices by pharmaceutical companies, such as commissioning the collection of large quantities of plant material without regard to the sustainability of the populations. Overharvesting is sometimes encouraged by market requirements. There is a widely held perception that plants collected from the wild are more effective than cultivated ones. This idea is even sometimes used as a marketing strategy. It may, however, have the effect of allowing producers to charge higher prices.

Sustained harvesting from the wild of species for which there is a commercial demand may lead to genetic erosion. This is the case for oregano in Turkey; loss of genetic variability has been recorded for several species, including Origanum onites (Kitiki, 1997). Likewise, overharvesting of agarwood (Aquilaria spp.), one of the most valuable non-timber forest products (NTFPs) of Asia, has been reported from certain parts of its range such as India and Viet Nam. The fungus-infested wood is stained by oleoresins and the oil derived from it is used in the production of incense, perfume and certain traditional medicines. There is strong demand from countries in the Near East, and there is evidence of illegal trade. At least two species are particularly at risk, A. malaccensis and A. crassna, and proposals have been made for their listing in the appendixes of the Convention on Trade in Endangered Species of Wild Fauna and Flora (CITES).

Introduced and invasive species

One of the greatest threats to natural and semi-natural vegetation, which is often overlooked, is the deliberate human introduction of species - of trees and fodder crops, for example - which have largely replaced the native ecosystems. Introduced species may also be a threat to productive systems. Examples are the introduced palaeotropical grasses which have become, since the 1840s, major agents in facilitating deforestation in Central and South America, and the trees and shrubs introduced into the very diverse Fynbos and Karoo formations of South Africa, which have had a devastating effect, putting at risk over 50 percent of the component species. Many grasslands in both temperate and tropical regions - in Australia, California in the United States, Africa and Central and South America - are seriously affected by alien invasive species.

The major problems are caused by the following:

On the other hand, many weedy species are tolerated or even encouraged in traditional farm systems such as home gardens, where they may be an important resource.



If the potential of wild plant resources is to be developed and sustainably used by local farmers, then ownership, whether communal or private, of the land and the resources must be clearly established. There is little incentive for farmers to engage in development activities if land tenure is weak or uncertain. Many rural households, especially those with little land of their own, rely on common property areas for gathering wild plants or plant products that contribute to their household economies and complement agricultural production. Common lands also provide employment opportunities for those without land, for small farmers and farm workers and for women and children. These uncultivated lands also have important ecological functions such as provision of ecosystem services. Government policy decisions that favour economic development, such as paper pulp production, creation of dams and other waterworks, privatization and land expropriation for agricultural production, have led to reduced access to common property areas.

In India, for example, in addition to the effects of colonial rule in asserting sovereignty over most of the uncultivated land, most of which was not reversed after independence, the area of common lands in semi-arid regions declined by 30 to 50 percent between 1950 and 1980 (Figure 7).

The loss of common property resources may bear especially heavily on women, since they usually have greater access to common land in rural areas than to privately owned land; consequently, any reduction in access undermines the economic base of women more than that of men (Repetto, 1994).

Decline of common property areas in India

Note: Products collected include fruits, flowers, leaves, roots, timber, fuel, etc. Watering points include common property resources for grazing only.

Source: Repetto, 1994, based on Jodha, 1992.

The effects of constraints on access to common lands can be countered to some degree by:

Intellectual property rights

The allocation of property rights is an important issue for local communities and affects their attitudes to both wild harvesting and home gardens. In the case of wild harvesting of medicinal plants, provided regulations ensuring sustainable practices are applied, property rights need to be guaranteed to the gatherers to ensure long-term exploitation of the resource. However, the rights must be allocated at the community level and not to individuals, through negotiated agreements with traditional healer associations or community leaders who can play an important part in monitoring or controlling the use of resources.

Environmental legislation

The use of wild species is often regulated or restricted by some form of environmental legislation. However, local farming communities are unlikely to know about relevant laws or regulations. Therefore action needs to be taken in the form of awareness campaigns or education programmes to ensure wider knowledge, on the part of local communities, individuals, local government, traders, agricultural extension officers, aid officers, conservation agencies, industry and consumers, of legislation affecting the plants that are consumed or harvested. Local, national, regional and international treaties, conventions and agreements such as CITES need to be respected.

In particular, attention should be drawn to legislative frameworks that are being developed to implement Article 15 of the Convention on Biological Diversity, which defines the rights and obligations of contracting parties regarding access to genetic resources and fair and equitable sharing of benefits derived from their use (Glowka, 1997).

Availability of germplasm for traditional farmers

Lack of availability of or access to suitable or improved germplasm may be a serious constraint to developing and enhancing the productivity of traditional farming systems. While seeds and other propagules may be available through seed networks, community nurseries and other local and traditional systems, many farm families may not be able to afford to obtain propagation material by purchase or barter. Little effort has been made by the formal genetic resources system or by agricultural extension services to address or meet this demand.

There are several reasons for the limited collecting and availability of genetic resources of wild or semi-domesticated material:



Small farmers and pastoralists can only be expected to change their practices if they have the appropriate incentive to do so. Marginal farmers and pastoralists operate largely outside the market economy, so their response to market signals is limited. Likewise, market instruments are likely to have little effect on subsistence producers. As a consequence, non-market controls and regulations will have to be used to improve practices through local community action.

Economic calculus

A major constraint facing attempts to enhance the productivity of rural farm households is not just the lack of information on which wild plant resources are used, how and in what quantities, but the lack of adequate indicators to measure this kind of economic activity. Even if there are no individually ascribed property rights and goods and environmental services are unpriced, the way in which social costs are incurred and social benefits are impaired should appear in the macro-economic calculus. In tenancy terms this would be equivalent to a full repair and maintenance lease whereby the natural capital or environmental assets remain intact and are renewed when they are used up or degraded (Lingard, 1994).

Leaving aside accounting value to the national economy, a number of indicators of the value of wild resources to rural households have been proposed (de Beer and McDermott, 1996; Broekhoven, 1996), largely based on NTFPs (see Box 22).

BOX 22


Quantifiable indicators

  • Numbers of species of wild plants used, arranged by category of use
  • Frequency of collection and consumption of wild plants or their products
  • Quantities collected and consumed
  • Numbers and percentage of the community or household who consume wild plants or their products
  • Numbers and percentage of the community or household who are engaged in the collection, trading and processing of wild plant products
  • Percentage of nutrition supplied to the diet by wild plants (energy, protein, fat, etc.)
  • Percentage of household time spent on activities related to wild plants
  • Availability of raw material in the wild

Indicators related to monetary value

  • Local market prices for wild plants
  • Household income obtained from wild plants (percentage or gross)
  • Payment for labour related to the collection, harvesting or processing of wild plants and comparison with other forms of employment
  • Prices received by collectors

Non-quantifiable (qualitative) indicators

  • The response of people to a decline in wild plant resources
  • The value of wild plants as reflected in tenure, ownership and use rights
  • Traditional local knowledge of the uses and management of wild plants
  • Use and distribution of wild plant species in home gardens, farms and fallows
  • Attitudes, perceptions and preferences of rural people or groups (women, children, rural poor) regarding wild plants and changes in their availability

There is a risk that the promotion of wild plant products such as NTFPs may result in overharvesting, a drop in prices and a consequent threat to ecological and economic sustainability, as well as having negative effects on the collectors themselves (van Valkenberg, 1997). One solution is to increase diversification and so reduce dependency on a small number of products or species.


The lack of public agricultural support services is a major constraint to developing the use of wild plants in farm households. Certainly public support services have been instrumental in promoting technological and managerial innovation in developing countries in order to reduce poverty and foster economic growth and have contributed to significant agricultural growth rates in many countries. Such growth has, however, been largely concentrated in reliably rainfed or irrigated areas, whereas in marginal or other agro-ecologically and socio-economically complex and difficult areas living standards have shown only minor improvements (Farrington et al., 1997). In a recent review of farmer-led extension (Scarborough et al., 1997) it has been suggested that a critical barrier to development in these areas is the failure to find institutionally viable ways of providing appropriate technical support to farm households.

There are serious constraints to the application of technological advances for resource-poor rural farmers who live at or below poverty thresholds and use wild plant resources as part of their survival strategy. It is estimated that worldwide about a thousand million people live in such conditions. Innovations have to be targeted specifically at local needs, and to make this possible, agricultural research and extension services must become more responsive to the particular needs and constraints of rural farm households.

Disenchantment with large-scale involvement of the public sector in agricultural extension has already led to action in many parts of the world to change or refocus this involvement. It has been suggested that governments should adopt a multiple approach to extension, including privatization of public extension services. Extension services have too often focused on facilitating technological change at the farm level with a view to enhancing productivity, while paying little attention to the sustainability of farming systems. Sustainability involves socio-economic and institutional issues. For example, in subsistence farm households, agricultural development must provide sustainable livelihoods, especially in cases where the households have few resources and little opportunity for off-farm work.

The contribution of wild plants, either gathered or cultivated in home gardens or fallows, needs to be taken into account in planning and assessing the extension models proposed. Many of the millions of rural families in developing countries that are involved in the use of wild species are specifically poor, so investment in the development of these resources will make a major contribution to the alleviation of poverty. Failure to do so will lead to increasing marginalization of wild plants with disastrous consequences for those whose lives depend on them to a significant degree.

As regards the domestication and cultivation of wild species, although considerable experience has been gained locally in, for example, home gardens, the introduction of new species into cultivation as cash crops will usually require considerable investment of time and money since it involves selection of material, screening of available germplasm, germination and propagation studies and research into cultivation methods (irrigation, fertilization, harvesting technology, etc.). Trials and field-scale experimentation over an extended period, as well as processing and marketing research, will be necessary, and these activities are normally beyond the capacity of rural entrepreneurs. Such activities will need the support of State or private research institutions and universities, and they could be included in many agricultural and rural development projects.

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