Setting of the ecosystem conservation standard
By Measuring biodiversity
Department of Sericulture and Entomology
National Institute of Agricultural Science and Technology
Rural Development Administration, KOREA
For the last 100 years, Earth has undergone dramatic changes. Natural and political landscapes are quite different than they were at the end of World War II. As science and technology develop, we are in a closer neighborhood than ever before and the Earth is no longer a world of distant lands and unfamiliar cultures. No country can escape from global environmental and socioeconomic changes, while local or regional development activities no longer remain localized but contribute to global issues.
As the human exploitation on nature accelerates helped by the technological advances of men, ecosystem on Earth is now being threatened to total destruction. The loss of biodiversity indicated a warning sign on the sustainability of the human life-support system. The rapid increase of human population demands a continued economic development, and this in turn requires more exploitation of the remaining biodiversity (Western and Pearl 1989).
Ecosystem conservation is now gaining weight as a viable solution to the preservation of endangered and threatened species. Safeguarding the component species is the basic step for sustaining the dynamics of basic ecosystem processes. In this paper, we would like to discuss the essence of biodiversity conservation and the strategy for keeping it.
WHAT IS BIODIVERSITY?
It is not too hard to guess about the meaning of "biodiversity" these days as our concern about the environment and ecosystem grows. What is biodiversity? Biodiversity is not just a simple collection of species. No species is endowed with all genetic and phenotypic attributes to fit into every ecological niche, and no single species can survive alone without interaction with other species (Noss 1990). Biodiversity refers to the diversity of life (Wilson 1992) that is the integration of varieties and variation of all living organisms as related to their habitats and ecological complexes.
Measuring biodiversity can be used to evaluate the state of the environmental exploitation. Species can be used to assess and monitor the state of biodiversity and the health of ecosystem. Therefore, careful selection of species and their relative biodiversity at certain ecosystem can be used as the indicator of the ecosystem conservation standard.
Since the life on Earth began about three billion years ago, major events of extinction on biological species have taken place. Although they appeared to be relatively rapid, those geological extinctions, by natural environmental causes, were gradual in evolutionary time, taking long time before species permanently disappeared and the ecosystem impact became apparent (Patrusky 1986; Kaufman and Malloy 1986; Raup 1988, 1991; Jablonski 1991).
These kinds of extinction took many hundred-thousands years to millions of years, while those induced by human activities take only little less than 100 years. The rate of species extinction by deforestration alone is about 10,000 times greater than the natural extinction prior to the Industrial Revolution. Ecosystem usually requires time to adjust and reorganize in response to massive loss of species.
Extinction is a natural process to eliminate an evolutionary lineage, and caused by both biological and environmental factors operating at the habitat and ecosystem level. Humans are directly responsible for the current mass extinction caused by habitat destruction (Saunders et al. 1991). The problems are getting worse as the human population increases. In 1992, human population was about 5.5 billion. Now the population is more than 6 million. With the projected growth of human population, damage to the ecosystem on the Earth will likely continues.
With the impoverishment of biodiversity, we are losing the most basic resources on Earth, which are the essential material basis of all human activities and needs. Extinction of a species means not only the loss of a collection of organisms, but also the breakage of the intricate interactions of the remaining component species (Vermeij, 1986; Robinson et al., 1992). This is especially true for those species that are obligate, permanent or host specific. Along with the loss of species, the dynamic ecosystem process will be disrupted, and if disruption is severe enough, the ecosystem may collapse (Samways, 1989).
As biodiversity issues are complex and broad with regard to the causes of anthropogenic extinction, biodiversity conservation should be focused on preserving the dynamics of ecosystem processes by protecting the ecosystem structure and function, which in turn will minimize extinction. To develop conservation plans, the following questions must be asked:
1. Where do we need to survey?
2. How do we assess biodiversity composition and structure?
3. What must we save for ecosystem conservation?
4. How do we restore and monitor it?
Conservation activities must address these issues at different geographic and organization levels. It needs to be emphasized that sound conservation efforts must be based on biodiversity inventory data. Species richness, endemism, or biogeographic and phylogenetic significance must be considered as well.
Measuring diversity is the key factor in Ecosystem conservation. To identify which species to observe on the basis of its ecological niche, the ecosystem in question is to be examined by ecologists of different speciality. A set of component species which is most important to maintain that ecosystem can then be selected. These species are then studied and the data is accumulated. Data such as species richness, endemism, species disparity and turn-over rate can be analysed to determine the state of ecosystem exploitation.
Invertebates, especially insects, are particularly useful on measuring biodiversity. Many of them are herbivores, starting right at the bottom of the ecological ladder. Most of them are highly sensitive to the changes in the environment which they live on. Many studies on using invertebrate biodiversity as bioindicators of ecosystem conservation and sustainable landscape have been published since the start of last decade.
Long-term study on the ecological characteristics of such component species will provide the data which can be used to set the standard for the ecosystem conservation. It is therefore crucial to understand the basic ecological mechanisms of the species selected, and their interactions.
Jablonski, D. 1991. Extinctions: A Paleontological perspective. Science 253: 754-757
Kaufman, L. and Malloy, K. (Eds.) 1986. The last extinction. Cambridge, Matt.. : MIT Express.
Noss, R.F. 1990. Indicators for monitoring biodiversity: a hierarchial approch. Conservation Biology, 4: 355-364.
Patrusky, B. 1986. Mass extinctions: the biological side. Mosaic, 17(4): 2-13
Raup, D.M. 1988. Extinction in the geologic past. In Origins and Extinctions. New Haven, Conn.. : Yale univ. Press.
Raup, D.M. 1991. Extinction: Bad genes or bad luck. New York: W.W. Norton & Co.
Robinson, G.R., Holt, R.D., Gaines, M.S., Hamburg, S.P., Johnson, M.L., Fitch, H.S. and Martinko, E.A. 1992. Diverse and contracting effects of habitat fragmentation. Science, 257: 524-526
Samways, M.J. 1989. Insect conservation and the disturbance landscape. Agriculture, Ecosystem and Environment, 27: 183-194
Saunders, D.A., Hobbs, R.J. and Marguler, C.R. 1991. Bilogical consequences of ecosystem fragmentation: a review. Conservation Biology, 5: 18-32
Vermeij, G.J. 1986. The biology of human-caused extinction. In The preservation of Species: The value of Biological diversity. Princeton Univ. Press.
Western, D. and Pearl, M. 1989. Conservation for the Twenty-first century. New-York, Oxford University Press
Wilson, E.O. 1992. The diversity of Life. Cambridge, Mass.. : The Belknap Press of Harvard Univ. Press.