Importance of biodiversity
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Importance of biodiversity Document Transcript

  • 1. Importance of biodiversityMany biologists who study biodiversity confine themselves to theobjective assessment of ecological processes. Others believethat scientists should comment on the moral, philosophical andpolitical aspects of biodiversity.The first approach risks losing many species of plants andanimals to exploitation or development, whereas the secondleads people to question the impartiality of scientificconclusions. Which do you think is preferable?Arguments for protecting biodiversity fall into twocategories:Biodiversity has an intrinsic value that is worth protectingregardless of its value to humans. This argument focuses on theconservation of all species, even if they are ecologicallyequivalent species.Biodiversity performs a number of ecological services forhumankind that have economic, aesthetic or recreational value.This argument focuses on conserving ecologically nonequivalentspecies since ecologically equivalent ones are redundant interms of services rendered(G. Bell, pers comm).Both points of view (intrinsic and anthropocentric) need not becontradictory, as they serve the same ultimate purpose. Yet theyoften are considered incompatible because they stem from twovery different philosophies: one which views nature as innatelyvaluable and one that regards it as economically valuable.Both the intrinsic value and the anthropocentric values arepresented in this page. The debate regarding the value of
  • 2. biodiversity and the need to protect it is still very hotly contested.The reader is left to draw their own conclusions from thearguments presented.Intrinsic ValueThe first argument for the intrinsic value of biodiversity is the ideathat humans are part of nature."We know now what was unknown to all the preceding caravanof generations: that men are only fellow-voyagers with othercreatures in the odyssey of evolution... Above all we should, inthe century since Darwin, have come to know that man, whilenow captain of the adventuring ship, is hardly the sole object ofits quest, and that prior assumptions to this effect arose from thesimple necessity of whistling in the dark." - Aldo Leopold, A SandCounty Almanac.The argument for conservation of biodiversity often emphasizesthe need to facilitate continued evolution. As humans are andwere part of nature, they benefited from the evolutionaryprocess. The tenet that humans are part of nature questionswhether humans should endanger their own milieu and theprocess from which they stem.
  • 3. A corollary to the aboveargument is reflected inthe Noah principle , namedfor the biblical Noah who saved one pair of every creature onearth in the Ark, which argues that the usefulness of a species isnot considered when discussing its conservation, but rather itsvery presence in the long history of evolution is sufficient towarrant its preservation."The non-humanistic value of communities and species is thesimplest of all to state: they should be conserved because theyexist and because this existence is itself but the presentexpression of a continuing historical process of immenseantiquity and majesty. Long standing existence in Nature isdeemed to carry with it the unimpeachable right to continuedexistence" D.Ehrenfeld, Conserving Life on Earth 1972Environmental ethicists also stress that humans should protectbiodiversity because they are the cause of most of the loss ofbiodiversity through loss of habitat, overexploitation and otherperturbations."99 percent of all species that ever lived are now extinct. But Ithink we have an obligation, now, in our generation and inforeseeable generations, to try to protect every species, try tomaintain every species, because virtually every species that isgoing extinct now is going extinct due to human activity notbecause of natural processes" R. Noss, 1996(Takacs, 1996)Ethics and environment: extension of rights tospecies and landformsWhile many people will challenge us with the notion thatprotection of the environment is morally good, philosophy and
  • 4. religion have not incorporated the concept of natureconservation; it is not yet included in our ethical framework. Theprocess of inclusion of these issues is one of social evolution.The concept of stewardship, however, is one firmly ensconced inthe Judeo-Christian doctrine.Some people suggest that the idea of biodiversity reachestowards oneness, toward a unity of all living and non-livingthings. When anthropocentric attempts at valuing biodiversity areput aside, what remains are the realm of the emotional, spiritualand religious justifications. However, skeptics counter that thespiritual and religious holds of biodiversity on humans maysimply be due to our lack of understanding of it. (Takacs,1996 , p. 98)The noted Harvard biologist E.O. Wilson champions the idea thatlove of nature has been "hardwired" into us by natural selection.The religious feelings that the concepts of biodiversity and naturecan arouse in some can be seen as a natural extension of atendency to focus on life and lifelike processes. Wilson coinedthis idea "Biophilia"It is pointed out that humans, while removed from nature, stillneed to be surrounded by nature and they respond to thisfundamental need by visiting natural parks and bringing natureinto their daily lives with pets and plants. But can this apparentlove for nature be interpreted as love for biodiversity? Indeed, the
  • 5. notion of biophilia is often countered by the perception thathumans want the nature surrounding them to be managed andartificial - green lawns and no pests - not natural and diverse.(A great reference for more information is a book entitled The Idea of Biodiversity by Takacs, 1996)Anthropocentric ValueWhile intrinsic arguments for protection of biodiversity arecompelling, it is ultimately arguments of human benefit thatpragmetic conservationists find most appealing: as humans, weare inextricably and wholly dependent on this diversity of livingthings for survival.Biodiversity, encompassing genetic diversity, species,populations, communities and ecosystems, and landscapes andregions, provides countless benefits to humans at all thesescales. Some of these benefits include:Economic benefits, both direct and indirect;Aesthetic benefits;Scientific and ethical knowledge;Insurance against the future
  • 6. Economic benefitsThe notion that biodiversity has provided us with many benefits iswell understood. Some of these benefits come in the formof goods that can be directly valued and costed because theyprovide something that can be extracted and sold. These goodsinclude everything from all the domesticated agricultural cropsthat form the basis of the worlds food supply, to medicines thatprotect and cure us to the fibres that make up the clothes wewear. Thus biodiversity is widely valued as food pantry, geneticstorehouse for biotechnology and a place to retreat to when weneed to get away from our hectic urban existence.Biodiversity also provides critical indirect benefits to humans thatare difficult to quantify because we have never had to put a pricetag on them. These benefits encompass ecosystem services ,such as air and water purification, climate regulation, and thegeneration of moisture and oxygen. A group of ecologists whorecently attempted to quantify the price of replacing theseecosystem services calculated that they would cost over $3trillion. Thats greater than the entire global GNP! In other words,the world cannot afford to replace these services, therefore wemust work to protect our ecosystems.Natural communities maintain proper gaseous concentrations inthe atmosphere and prevent rapid climate changes. Drasticchanges in the Earths atmosphere can have catastrophiceffects. Such changes are believed to have led to thedisappearance of dinosaurs from Earth 65 million years ago.Much less drastic changes resulted in several global ice ages,the last of which ended 10 thousand years ago.Vegetation helps recycle moisture into the atmosphere. A singlecorn plant (1 lb dry weight) can transfer 60 gallons of water fromsoil to atmosphere in a few months. A single rainforest tree, in its
  • 7. 100 year lifespan can transfer approximately 2.5 million gallonsfrom soil to air. Their role in the hydrologic cycle is crucial.A multiplicity of organisms is required to create soils andmaintain fertility through complex cycles and interactions. Plantroots break up rock to create soil particles, small animals likeearthworms, mites, insects and millipedes help give soil itstexture and fertility and are crucial to its aeration. Even tinier soilmicroorganisms and fungi are responsible for cycling essentialnutrients like nitrogen, phosphorus and sulfur and making themavailable to higher plants. And their numbers are staggering. Agram of fertile agricultural soil may contain 2.5 billion bacteria,400 000 fungi, 50 000 algae and 30 000 protozoa. All theseorganisms have particular functions and interact with each otherand with their physical environment to create the fertile soil thathumans depend on for agricultural production.Natural ecosystems also help absorb the wastes we create andrender them nontoxic. Wetlands are large filters which purifyfreshwater and remove heavy metals and other contaminantsfrom it. We often depend on rivers to flush away and break downthe sewage and effluents that we put into them, which againdepends on the array of small and large organisms thatdecompose and transform wastes in water. Soil organisms canslowly decompose food items, paper products and other wastesproduced by human activities. (Erlich and Erlich, 1992)Economic arguments for protecting biodiversity are criticized forbeing too utilitarian and human-centered. Indeed, an excessiveemphasis on the economic values of different species is seen asdangerous for two reasons: there is bias towards the protectionof species and ecosystems that have attributable economic valueand this perspective may also lead to the conclusion thatecosystems that are not directly benefitting humans are worthmore to humans developed than undeveloped.
  • 8. Aesthetic value and recreationIn North America, protected wild areas where indigenousorganisms live undisturbed give people a sense of satisfaction inknowing that there are bears and wolves and rare plants andinsects that still exist on their continent. Natural and wildlandscapes are aesthetically pleasing and provide opportunitiesto get away from human-dominated landscapes. They alsoprovide opportunities for recreational activities such as hiking,canoeing, birdwatching and nature photography.(Erlich andErlich, 1992)This argument is criticized for two reasons: first, aesthetic valueis not necessarily equated to biodiversity; some of the mostaesthetically pleasing landscapes are poor in diversity of habitatsand species (e.g. mountains) while some unspectacularlandscapes are incredibly rich in biodiversity (e.g. swamps andwetlands). Second, this aesthetic argument is relevant only to aminority of wealthy citizens in developed countries and holds littlerelevance to the majority of the worlds population(Takacs, 1996)Future potentialWhile there are hundreds of examples of known economic andaesthetic benefits of biodiversity, biologists and other scientistsfrequently outline that more is unknown than known. Importantecosystem services and uses for plants and animals are stillunknown and await discovery. Yet these cannot be discovered,and benefit humankind, if they disappear before discovery. Thethreat to biodiversity can be compared to book burning (theobliteration of former and future knowledge).Many of our valuable goods, from spices (cinnamon, pepper) tocritical medications (aspirin, tamoxifen, quinine, digitalis) have
  • 9. been discovered "accidentally" because plants or animalsproduced chemicals for defense or attraction. We would not haveotherwise considered the organisms from which these chemicalsoriginated as valuable and worthy of conservation.