Study 3: Ecodestruction and the Right to Food: The Cases of Water ...

Starving the Future Study 3
vi. Alien species
Species are “alien species” in an ecosystem if they were introduced into the ecosystem comparatively
recently - usually by human intervention. Alien species are responsible for many recorded species
extinctions, especially on islands. In these isolated ecosystems, a new predator, competitor, or
pathogen can rapidly imperil species that did no co-evolve with the newcomer. In Hawaii for example,
some 86 alien plant species seriously threaten native biodiversity; one of them has now displaced more
than 30.000 acres of native trees, resulting in large changes in ecosystem dynamics. One of the alien
tree species has the ability to convert atmospheric nitrogen to ammonia just like peas and beans. This
ability increases the nitrogen content of soils, and thus alters the raw materials on which many other
plant species depend. Another example for the adverse effect of alien species was the well-meant
introduction of game fish to many lakes and streams throughout the world, resulting in the replacement
of many native varieties.
vii. Global climate change
Human-caused increases in “greenhouse gases” (mostly CO2 from fossile fuels) in the atmosphere are
likely to commit the planet to a global temperature rise of some 1 to 3 degrees Celsius during the
century, with an associated rise in sea level of 1 to 2 meters. With this global warming some species will
find less optimal habitat than before, particularly in higher latitudes. Plants and animals that now inhabit
montane and alpine habitats - and which are there through an evolved dependence on cooler
temperatures and higher altitudes - may with warming of these regions have nowhere else to go. Each
1°C rise in temperature will displace the limits of tolerance of land species some 125 kilometers toward
the poles, or 150 meters vertically on the mountains. Many species will not be able to redistribute
themselves fast enough to keep up with the projected changes, and considerable alterations in
ecosystem structure and function are likely.
Ecologically and socially acceptable management of biodiversity is a prerequisite for the preservation of
the wealth and productivity of natural ecological systems. The Agenda 21 adopted at the UNCED in Rio
in 1992 calls for concerted action by governments, governmental and non-governmental organizations,
and the scientific community for the preservation of biodiversity.
References:
• Dobson A., Campbell M.S., Bell J., Fatal synergisms: interactions between infectious diseases, human
population growth, and loss of biodiversity.
• Grifo F., Rosenthal J., editors (1997). Biodiversity and human health. Washington, DC: Island Press, 1997:
87-110.
• Daily G., Ehrlich P. (1992). Population, sustainability, and Earth's carrying capacity. Bioscience, 42, 761-771.
• Daily G. et al. Ecosystem services: Benefits supplied to human society by natural ecosystems:
http://esa.sdsc.edu/daily.html
• Hughes J. B., Daily G. C., Ehrlich P. R. (1997). Science 278, 689.
• Farnsworth N. R., Akerele O., Bingel A. S., Soejarto D. D., Guo Z. (1985). Medicinal Plants in Therapy.
Bulletin of the World Health Organization, 63(6): 965-981
• Lawton and May (1995): http://essp.csumb.edu/esse/ecoservintro/ecoservthreats.html
• Wilson E.O. (1989). Threats to biodiversity. Scientific American 261: 108-16.
• C. Pearl, 54-69. New York: Oxford University Press.
• FAO, Food For All (1996)
• FAO: www.fao.org/biodiversity/index.asp
• Tuxill J. (1999). Nature’s Cornucopia: Our stake in plant diverstiy, WorldWatch Paper 148.
• Biodiversity and protected areas, World Resources Institute: www.wri.org/biodiv/bri-why.html
• New Biodiversity Assessment, World Resources Institute: www.igc.org/wri/wr-96-97/bi_txt2.html
• Global Biodiversity Assessment, Policymaker’s summary, United Nation Environment Programme (UNEP,
1996): www.unep.org
• Loss of biodiverstiy: www.earthgreen.org/biodiversity.htm
FIAN International 112
June 2002