People, Plants and Protected Areas

A Guide to in Situ Management

John Tuxill, Gary Paul Nabhan, with Elizabeth Drexler, Michael Hathaway

• Publisher: Routledge
• Year: 2013
• Print ISBN:
  9781138407114
• eBook ISBN:
  9781134203932
• Topic: Biological Sciences
• Subtopic: Ecology
• Index: Biological Sciences

Conservation of plant resources is often focused on seed banks and botanical gardens. However, the two authors of this volume present a comprehensive conservation strategy that complements this ex-situ approach with practical guidance on in-situ management and conservation of plant resources. The book aims to facilitate better management of protected areas and to illustrate new approaches to conservation of plants within their landscapes. It draws on concepts from forestry, the agricultural sciences, anthropology, ethnology and ethnobotany and should be useful to practitioners, academics and policy-makers.

1
Why conserve plant resources in situ?

Figure 1.1 A community-initiated botanical nursery for endangered cacti and other rare plants at Miquihuana, Tamaulipas, Mexico. Rare plants found on community land that is due to be developed for roads, agriculture or other activities are transplanted to this site, where the plants are monitored and tended by community members. (Photograph: G.P. Nabhan.)

Any native plant can be considered a resource for humankind – and for associated animal and plant species – in that it contributes to the health and stability of the ecological community in which it occurs. However, in any flora there are certain plants that are more intimately linked with human welfare. These can generally be divided into two groups: those which are used directly for home consumption or local elaboration of products, or sold to generate income; and those which are used indirectly as sources of genes, cells, cuttings, or novel chemical compounds for products developed by agricultural, pharmaceutical, or related industries.

For the purposes of this manual, plants which are used directly by local communities for food, forage, fiber, timber, medicine, ceremony, symbol, or income will be called ethnobotanical resources. Plants which are processed or manipulated to extract genes or DNA for crop improvement, cells for tissue culture, or chemicals for precursors of pharmaceuticals will be called phytogenetic resources. When we wish to talk about both categories in general, we will refer to them as useful plant resources, or simply ‘plant resources’. Keep in mind that some plant resources may not fit neatly into either the ethnobotanical or phytogenetic category. Examples include commodity crops grown for international export or national consumption, or plants that are sold in a regional market by one community for direct use by another. In addition, some useful plants are phytogenetic resources to one person and ethnobotanical resources to another, a point to which we return in later chapters.

This manual will refer to both wild species and domesticated plants, such as crop landraces or folk varieties. We use the labels wild (for plants that grow and reproduce without human interference) and domestic (plants selected, sown, tended and harvested by people) loosely, since there is not always a clear distinction between the two. For instance, certain wild herbs of the genus Amaranthus prosper in farmers’ fields worldwide, and are often tended and harvested as nutritious green vegetables. While these herbs are not planted by farmers, they may have been selected to suit the ecological conditions of traditional croplands and other human-influenced vegetation; in scientific terms, such plants are called agrestals (field associates) or ruderals (roadside associates).

All people are in some way dependent upon both ethnobotanical and phytogenetic resources for their continued survival. High-yielding varieties of rice that feed hundreds of millions of people around the world owe their disease resistance to genes from a single accession, or sample, of the wild rice Oryza nivara collected in central India [179]. More than one-quarter of modem pharmaceuticals contain plant chemicals as active ingredients, and millions of people worldwide still rely upon herbal remedies gathered from wild habitats and home gardens for their primary health care [173]. Plant conservation, to be sure, is not simply an esoteric subject of interest only to botanists – it should be of concern to all of us who eat, use or otherwise benefit from contact with plants.

As human populations have grown exponentially over the past two centuries, they have modified habitats, translocated species, and altered the distribution and abundance of plant resources on a scale unprecedented in history. The 248 000 scientifically identified plant species make up about one-sixth of all species presently named, but estimates suggest that up to 50 000 species of plants may become extinct during the next three decades unless there is significant action to reduce pressures upon them [249]. Many plant resources that formerly were widespread and abundant enough to harvest routinely will be relegated to a precarious existence in densities too low to sustain certain uses. They may become totally dependent upon wise human intervention for their continued survival.

1.1 In situ and ex situ approaches to plant conservation

Two kinds of human intervention have aided the conservation and continued existence of threatened plants. We refer to them as ex situ (removed from habitat) and in situ (in habitat) approaches (Boxes 1.1 and 1.2). In practice, between these two conservation strategies lies a gradient of approaches to effective conservation. For example, a rare plant can be propagated along an interpretive trail within its natural range, where it may still exchange genes with surviving wild populations. Although its seed may have come from an ex situ gene bank, its propagation has placed it in an in situ context very similar to that in which its ancestors evolved.

Box 1.1 Ex situ maintenance

The removal of plants from native habitats, for translocation off-site to intensively managed facilities, represents ex situ conservation (Table 1.1). This conservation strategy may use botanical gardens, arboreta, seed banks, clonal repositories, or more sophisticated (and expensive) greenhouses and laboratories for frozen storage of propagules or tissue culture of cells (Figure 1.2). It can also involve the informal culture of wild plants in nurseries, home gardens, or community botanical gardens (Figure 1.3). Of course for traditionally cultivated crops, such home or community gardens are in situ rather than ex situ conservation sites – illustrating the overlap that exists between these terms.

During colonial eras, ex situ propagation fostered the rapid spread of economic plants from one continent to another. Rubber and cacao were taken from Brazil and established in Southeast Asia and West Africa, sugarcane and bananas were tranferred from Southeast Asia to the Caribbean and Central America, and coffee moved around the world from East Africa to Latin America by way of Indonesia. From cuttings of plants nurtured in botanical gardens to hybrid seeds of cereals developed in agricultural experiment stations, ex situ germplasm collections have revolutionized agriculture and forestry over the last 500 years.

Table 1.1 Comparing in situ and ex situ conservation approaches

	Purpose	Examples	Benefits
In situ	To maintain species and populations in the ecological and cultural context in which they have evolved	National parks Sacred groves and religious sites Wildlife refuges Nature reserves Community woodlots, grazing lands	Species, populations and gene pools continue to evolve and adapt Ecological interactions between species and species assemblages (communities) maintained All native species protected, not just those with known value Ecological services and processes (e.g. pollination, water filtration) maintained
Ex situ	To maintain species populations and genes in intensively managed, easily accessible environments	National gene banks Commercial seed banks Botanical gardens Agroforestry collections Home gardens	Species/varieties threatened insitu can be cultivated and propagated for reintroduction Convenient access to germplasm for breeders, farmers, herbalists, researchers and other users Species and varieties are readily available for conservation, research and education

For several decades now ex situ conservation has been pursued intemationally in a highly organized fashion, through government-supported seedbanks and institutions such as the Consultative Group on International Agricultural Research. Most of their attention has been directed at agricultural phytogenetic resources, but wild plants also are being maintained ex situ on an increasingly large scale. One major effort is the Millennium Seed Bank at the Royal Botanic Gardens, Kew, UK. This ex situ facility focuses on arid-adapted wild species from tropical and subtropical regions, and currently stores seeds of over 4000 species from more than 100 countries. Kew has campaign underway to expand this collection to 25 000 species by the year 2010. When achieved, this total will represent approximately 10% of the world’s known arid tropical and subtropical flora.

Figure 1.2 A field germplasm collection of cacao or chocolate (Theobroma cacao) trees near Port-of-Spain, Trinidad, managed by the University of the West Indies. Field gene banks are used for species like cacao whose seeds are recalcitrant, and cannot be stored for long periods under the dry, cold conditions of a conventional seedbank. (Photograph: R.P. Guries.)

Figure 1.3 Dooryard garden at Quitovac, a Sand Papago (Hia Ce’ed O’odham) community in Sonora, Mexico. Though such gardens are small in size, they often contain a diverse complement of local crop varieties grown for food, medicine, ornamental value and many other uses. (Photograph: G.P. Nabhan.)

This unprecedented assemblage of drylands species will not be merely held in storage, but will form a working ex situ collection, supporting a variety of education, training and research activities. Already, the Millennium Seed Bank distributes about 2000 small samples of seeds from its collection to researchers and organizations worldwide (the samples are sent free of charge to individuals in developing countries). Some seed recipients are studying the systematics of arid-lands plants, while others are conducting field trials to assess the potential of different tree species for arid-lands agroforestry. Certain species in the Millennium Seed Bank may also have commercial potential. For this reason, any use of seed samples for commercial purposes must be approved in advance by Kew, and in the event of financial success must adhere to the Kew policy of returning a portion of commercial profits back to the country in which the seed sample was collected. This question of how to recognize intellectual property rights to commercially valuable phytogenetic resources is a hotly debated aspect of both ex situ and in situ conservation, and is discussed further in section 6.11 of Chapter 6.

Box 1.2 In situ management

The protection of plants in their native habitats, termed...

Table of contents

• Cover
• Title
• Copyright
• Contents
• The ‘People and Plants’ Initiative
• Panel of advisers
• Foreword
• Preface
• 1 Why conserve plant resources in situ?
• 2 In situ plant conservation: who is involved?
• 3 Working with local communities
• 4 Setting priorities and planning for management
• 5 Monitoring and evaluating plant resource management
• 6 Traditional agriculture and plant conservation
• Appendices
• References
• Index