Lecture 18. Plant resource use and sustainability

Summary

Biological, economic and social criteria are used to assess the threats to the diversity and sustainability of botanical resources in various plant resource pools discussed in lecture 10.

Ethnobotanists are concerned by the loss of local varieties of the primary pool of cultivated plants, and by the disappearance of traditional agricultural systems. Apart from the general impact that this will have on human welfare – decreasing the genetic diversity of staple crops and the sustainability of agricultural production – we believe that the current trend of homogenization and mechanization of agriculture effectively divorces cultivated fields from the forests, savannas and other natural areas around them.

Another critical issue in many parts of the world is the unsustainable use of some resources that are in high demand regionally or internationally, but are not domesticated, cultivated or even appropriately managed. These plants, which make up part of the secondary pool of plant resources, are vulnerable to overharvesting for several reasons. They are typically slow-growing species primarily found in natural areas that may themselves be under threat of destruction by logging, plantation agriculture or other land-use schemes. Demand often outpaces supply, encouraging harvesters to move from one source area to another in a short period of time. The method of harvesting and the part of the plant commercialized often produce a lethal combination: trees are entirely debarked or are felled for their valuable wood, and other plants are pulled up by harvesters seeking certain types of roots. When the targeted resource is a dominant species in the ecosystem, harvesting can damage a wide range of plants and animals. Communities get few benefits when resources are exploited in this way. Harvesters and middlemen from outside the area typically make the profits, and local people are left only with a diminished resource base. The residents of Borneo, for example, have seen many resources affected by this boom-and-bust cycle, and several – such as gaharu wood, cinnamon bark and some rattans – are still exploited today. Finding permanent solutions to the overharvesting of these valuable resources is complex. One approach is to encourage protected area personnel to work with communities on monitoring and eventually cultivating the most vulnerable species.

Along with a focus on the primary and secondary pools of resources, it is important to address the tertiary pool of plants, those thousands of cultivated, managed or wild species used for subsistence. The diversity and utility of these plants provide local people with many provocative reasons to maintain and manage the vegetation around their communities. From natural and anthropogenic areas come fruits and vegetables that enrich diets, medicinal plants for many common ailments, firewood for cooking and heating, woods and other materials for household construction and a wide variety of crafts. As discussed above, many inputs into traditional agricultural systems flow from forests, savannas and other vegetation types. On occasion, these plant resources are brought to local marketplaces or other venues where they can be commercialized, augmenting the income of some community members. Above all, these plants form an important part of the security of rural people, providing benefits that cash cannot always buy.

Cultural, economic and political changes can threaten peoples’ access to these diverse resources. For example, conservation policies which exclude community members from protected areas where they traditionally hunted and gathered effectively cuts them off from traditional modes of subsistence. Turning forests and other lands over to logging concessions or plantation owners has a similar impact. With the resource base seriously diminished, people have to find other ways of satisfying their basic needs. Access may be limited in other subtle ways: when traditional knowledge and technology disappear – often a consequence of educational programs and economic policies – local people effectively lose their ability to use many resources. When urbanization pulls rural people away from their communities, they give up proximity to the forest, decreasing its utility to them. In the words of Gary Nabhan, people lose their sense of place. These changes diminish the value of natural areas from the perspective of the community and decreasing their incentive to conserve and manage plant resources. When the local environment plays a less important rôle in the spiritual and material life of the community, alternate views of land management begin to dominate. Lands once favored for traditional agriculture, forests once reserved for hunting and harvesting, become available for monoculture plantations, sale to outsiders and various types of destructive development. We have a limited understanding of how we can maintain and restore subsistence and knowledge systems based on the wide range of plant resources that comprise the tertiary pool of resources.

As we continue to focus on the knowledge and management of useful plants – whether from the primary, secondary or tertiary pools – we do not ignore the importance of the ensemble of species in the reserve pool. Although not currently used by communities, these plants make up the vegetation that provides numerous environmental benefits, such as watershed protection, erosion prevention, flood control and enrichment of abandoned agricultural lands. The beauty of some of these natural areas attracts tourists, providing cash flow into rural areas. Finally, it is the reserve pool that is the partial focus of some bioprospecting operations.

References:

Cunningham, A.B. 1993. African Medicinal Plants: Setting Priorities at the Interface between Conservation and Primary Healthcare. People and Plants Working Paper 1. Paris, UNESCO.

Ganesan, B. 1993. Extraction of non-timber forest products, including fodder and fuelwood, in Mudumalai, India. Economic Botany 47:268-274.

Godoy, R. and K.S. Bawa. 1993. The economic value and sustainable harvest of plants and animals from the tropical rain forest: assumptions, hypotheses, and methods. Economic Botany 47: 215-219.

Hall, P. and K.S. Bawa. 1993. Methods to assess the impact of extraction of non-timber tropical forest products on plant populations. Economic Botany 47: 234-247.

Hersch-Martinez, P. 1995. Commercialization of wild medicinal plants from southwest Puebla, Mexico. Economic Botany 49(2):197-206.

Konstant, T.L., S. Sullivan and A.B. Cunningham. 1995. The effects of utilization by people and livestock on Hyphaene petersiana (Arecaceae) basketry resources in the palm savanna of north-central Namibia. Economic Botany 49:345-356.

LaFrankie, J.V. 1994. Population dynamics of some tropical trees that yield non-timber forest products. Economic Botany 48(3):301-309.

Momberg, F. R. Puri and T. Jessup. 1997. Extractivism and extractive reserves in the Kayan Mentarang Nature Reserve: is gaharu a sustainably manageable resource? Pages 165 – 180 in Sorensen, K.W. and B. Morris, editors, People and Plants of Kayan Mentarang. London, World Wide Fund for Nature Indonesian Programme.

Plotkin, M. and L. Famolare. 1992. Sustainable Harvest and Marketing of Rain Forest Products. Washington, D.C., Island Press.

Sullivan, S., Konstant, T.L. and A.B. Cunningham. 1995. The impact of utilization of palm products on the population structure of the vegetable ivory palm (Hyphaene petersiana, Arecaceae) in north-central Namibia. Economic Botany 49:357-370.

Perspective for discussion:

"In ecological terms … extraction is considered sustainable if the harvest has no long term deleterious effect on the reproduction and regeneration of populations being harvested in comparison to equivalent non-harvested natural populations. Furthermore, sustainable harvest should have no discernible adverse affect on other species in the community, or on ecosystem structure and function. These effects also can also be determined by comparing harvested to unharvested systems. The adverse effects may be manifested in several ways. For example, harvesting of seeds and fruits decreases the availability of food for frugivore (fruit eating animals) populations, limiting the number of organisms and perhaps decreasing the diversity of frugivores in a given community. These changes in turn may alter other trophic (food web) relationships and thus negatively affect other species in the community. Even something as simple as removal of dead wood and leaves may devastate detritivore (decomposers, e.g. microbes, fungi, etc.) communities critical to the cycling of the nutrients which support the vegetation in the forest."

From Hall, P. and K.S. Bawa. 1993. Methods to assess the impact of extraction of non-timber tropical forest products on plant populations.

Questions for discussion:

• What are the ecological methods that have been used to assess sustainability?
• How can they be combined with studies of resource use by people?
• What impact does commercialization have on the sustainability of plant resources that are not cultivated, or are cultivated on a small scale?

Exercise:

(1) Indicators of plant resource sustainability

Materials: Pens, Post-its, Whiteboard

Instructions:

Ask participants to write down as many indicators of plant resource sustainability as they can on pieces of paper or post-its. This can be done individually or in small groups. These indicators could include general or specific concepts such as "plant part used", "commercialisation", "local perception of scarcity", "price", "ease of finding substitutes", "life-form of the plant", "abundance of the plant", "geographic distribution of the resource", "size/class distribution of measured populations", "proximity of urban zones" and many others.

After each person or group has finished, the post-its are categorised by similarity. First, one person or group representative puts the post-its in the order they choose, sticking or pinning them on the whiteboard. Then the next set of post-its is added, and so on until all indicators are posted. As a group, participants are asked to characterise the grouped indicators, giving a name to each cluster (e.g. social, cultural and economic factors or some other ordering) and to discuss the logic behind the categorisation.

Participants are then asked if they would like to re-order the post-its in any way. After any final discussion, a diagram of interlocking spheres indicating social, cultural and economic factors can be drawn around the indicators, showing that the most critically endangered resources are those found at the junction

If there is time, participants can be asked to freelist specific key resources from their area, and place them in an appropriate place on the diagram.

(2) Assessing the sustainability of plants used in artefacts

Time: About two – three hours

Materials: One or a series of artefacts made from one or more plant resources; Access to: (1) herbarium collections of plants used in making the artefact; (2) a botanical library or key references on the artefact, and the species used to make it; (3) relevant databases, such as the Economic Botany Bibliographic Database; (4) people with expertise, be they resource users, artisans, botanists, etc.

Instructions:

Have participants divide themselves into small groups of 2-3 people. Give each group an artefact or series of artefacts (i.e. similar in terms of style or plant resource used); examples include palm hats, grass/reed baskets, wooden bowls and so on.

Ask each group to assess the sustainability of the craft item, from a biological, cultural, and ecological point of view. Describing the range resources at hand, including experts, databases, herbarium collections, and bibliographic references.

After about one – two hours of research, each group is to write an assessment of the sustainability of the craft, and explain their results to the whole group.

This exercise can follow on from the "Indicators of plant resource sustainability" exercise

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