L25 human societies

Conservation and Human Societies

• preservation of biological diversity is often in conflict with actual and perceived human needs

• what is sustainable development ? - economic development to satisfy present and future needs while minimizing impacts on biodiversity

• the concept is often misused by corporations, governments etc.

The Ultimate Source of the Biodiversity Crisis

if current predictions of human population growth prove accurate science and technology may not be able to prevent irreversible degradation of the natural environment...

...dealing successfully with environmental problems will require the achievement of zero population growth...

30 billion people

present

• present human population 6 billion people

• 95% of the earth’s surface is occupied by human settlements or ecosystems managed for food and materials production

• natural ecosystems are under increasing pressure - fragmentation, species extinction, loss of global genetic diversity

• cannot feed the projected human population by simply increasing the area used for food production

• the enormity of the crisis has stimulated efforts to conserve biodiversity and use resources sustainably

Conserving Agricultural Genetic Diversity

Potato: 1830’s European ‘potato famine” was caused by susceptibility to fungal disease

• potato varieties grown came from a limited genetic source

• diverse localized populations in South America provided disease resistance

• occurred because 70% of USA corn was developed using a single genetic source susceptible to the pathogen ( ie. lack of genetic variability)

• genetic uniformity is recognized as “dangerous” because of inability to respond to biotic and abiotic environmental pressures

Corn:

•1970 failure of corn crops from “corn leaf blight”

• agricultural genetic diversity in pre-industrialized societies is high

eg. indigenous cultivars of maize from Mexico vary in

• time to maturity from 60 days to 16 months

• height from 40 to 700cm

• ear lengths range from 4 to 40cm

teosinte -maize wild relative- in Mexico

• loss of diversity is associated with “modern” agricultural methods

variation in fruit form in tomato (Lycopersicon esculentum)

variation in cabbage leaf type in Brassica oleracea acephala

• striking morphological examples of genetic diversity

• genetic conservation of important agricultural crops began early in the 20th century

• loss of primitive varieties of crop species -- “landraces” -- meant loss of genetic variation essential for sustained crop improvement

• systematic collection of seeds of indigenous crop varieties

• understanding of geographic distribution of genetic variation in crops

varieties of wheat

primitive wheat varieties (landraces)

• germplasm (= the DNA = mostly seeds) in these collections represent over 3,600,000 genetically distinct samples from about 100 crop species and their wild relatives

• seed in these “seed-banks” held at -88C and periodically propagated to preserve viability

• these ex situ collections are essentially the only genetic resource used for crop improvements

Primack 1998 Ch 14

Australian National Botanic Gardens seed bank

Pest-Resistant Crops and Genetic Diversity

• maintaining agricultural productivity to meet world food needs depends on continued development of pest resistance

• developing host plant resistance (HPR) to insects and pathogens is a primary focus of food plant development

• HPR and resistance to pathogens is most frequently found in “unimproved” or wild landraces

eg. resistance of current varieties to 12 diseases of tomato originates in wild tomato varieties

in situ Conservation of Agricultural Biodiversity

1. preserved habitats containing wild populations of crop species

2. regions where cultivation of indigenous landraces is continued by “custodian” farmers in exchange for subsidies

indigenous rice variety grown in Vietnam - note no water!

• less expensive than ex situ

• variation is maintained by natural or indigenous cultural practices

selecting rice seeds and varieties in Vietnam

in situ (on farm) agricultural conservation aims to

1. conserve processes of evolution and adaptation of crops (dependent on farmers)

2. conserve diversity at ecosystem, species and intra-specific level

3. integrate farmers into the global genetic resources system

4. conserve ecosystem services

5. improve the livelihood of resource-poor farmers

6. maintain or increase farmers’ access to crop genetic resources

http://www.ipgri.cgiar.org

crop species show high genetic diversity in certain areas of the world

locations of in situ crop diversity and wild crop relatives conservation projects

Morocco

alfalfa, bean & barley farming system

farmer with a turnip landrace

Morocco contains a vast diversity of agro-ecosystems

• high Atlas Mountains

• oasis area

• Rif Mountains

priority crops

barley Hordeum vulgare

durum wheat Triticum turgidum

faba bean Vicia faba

alfalfa Medicago sativa

bread wheat Triticum aestivum

crops chosen on

• economic importance

• farmer knowledge of landraces - varieties for straw, food, abiotic stress

• scientific data indicating high genetic diversity

• extent of threats posed by new cultivars

Burkina Faso

seed storage

women farmers group

target crops

• sorghum Sorgum bicolor

• cowpea Vigna unguiculata

• pearl millet Pennisetum glaucum

• okra Abelmoschus spp.

• African potato Solenostomum

sorghum landrace

Nepal

• single households may maintain >20 varieties of the same crop

rice Oryza sativa maize Zea mays

finger millet Eleusine spp. beans

taro Colocasia esculenta mustard Brassica campestris

conserve, diversify, empower

Hungary

• project to re-introduce local varieties into farming systems

• quantify effects of restoring agrobiodiversity on agro-ecosystem functions, genetic diversity and economic development

farmer varieties of vegetables

Hungarian farmer with a maize landrace

• crop wild relatives are found naturally in agro-ecosystems near farms, but increasingly threatened

• many are found in centres of plant diversity and crop diversity in developing countries

• these farmers and countries lack resources to invest in the necessary conservation strategies

• global strategies to link these countries to International conservation agencies eg. UN FAO, IUCN

• current project involves countries like Armenia, Bolivia, Madagascar, Sri Lanka and Uzbekistan - all centres of crop diversity

Local Conservation in Developed Countries

• local, regional and state laws aim to regulate activities which directly impacts on species and ecosystems

• regulation of hunting & fishing - season, size catch etc.

• harvesting plants - certification of a permit eg. tree ferns, grass trees

• laws controlling land use can protect biodiversity - access, pollution levels, lighting fires etc.

• zoning laws - prevent development in sensitive areas; environmental impact statements

• passage and enforcement of conservation-related laws at a local level can be highly emotional

• public must be made to look beyond the immediate benefits of development

• eg. protection of water supplies may mean no development -no grazing, logging or housing - in water catchments

• the arguments of conservation may be misused by people to prevent development near them - “not in my backyard”

• this misuse damages true conservation efforts “by association”

• one of the most powerful means to protect biological diversity is to set aside intact biological communities as nature reserves, National Parks etc. - a means of in situ conservation

• Park Managers throughout the world cite conflicts with local people as their most serious problem

• in the developing world local people typically obtain many or all their resources from their immediate environment

• common to disregard the traditional rights of local people in establishing new conservation areas - ecocolonialism

Traditional Societies & Biological Diversity

• many traditional societies have a strong conservation ethic

• not stated in Western terms

• based on sustainable resource use

• traditional land use and farming practices are frequently responsible for the patterns of biological diversity we now observe

• needs of local people and conservation need to be reconciled

Tukano people of Brazil

• diet of root crops and river fish

• strong cultural prohibitions against cutting the forest along the Upper Rio Negro

• recognized as critical for maintaining fish populations

• extensive refuges for fish; fishing is permitted along less than 40% of the river margin

Primack 1998 Fig 20.8

Biological Diversity and Cultural Diversity

• strong association between cultural diversity and the occurrence of high biological diversity

• the development of landraces is often a response to human selection for desired traits

• they are adapted to local soils, climates and tastes

eg. the Nuba mountains of Sudan host 62 distinct human language groups, and grow dozens of landraces of sesame which are identified with particular tribes and places

• protection of traditional cultures within their traditional areas provides a dual opportunity for cultural as well as biological diversity conservation

• the rigid separation of lands used by local people and lands set aside for conservation is neither possible nor necessarily desirable

• Biosphere Reserves allow people to use resources with constraints

eg. harvesting of meat from big game in African Nature Reserves

• these Integrated Conservation-Development Projects are increasingly seen as one of the best conservation strategies