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Biodiversity Loss: Quick Facts

1. Biodiversity refers to the variety of life from the molecular to the ecosystem level. It has to do with the number and variety of species, ecological systems, and the genetic variability they contain. It includes genetic differences within each species - for example, among varieties of crops and breeds of livestock. Genetic materials determine the uniqueness of each individual and each species.

At the broadest level of biodiversity the major varieties of ecosystems are known as biomes, and include tundra, deserts, forests, woodlands, oceans, and grasslands. In each ecosystem, living creatures, including humans, form what is called a community, interacting with one another and with the air, water, and soil around them. It is the unique combination of biodiversity interacting with the rest of the environment that has made our planet capable of supporting human life.
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2. Biodiversity plays at least two roles in maintaining natural systems:

3. Life is an improbable occurrence. The conditions for life are a rare, if not unique, event in the universe.  Both the evolution and maintenance of life depends on an unusual blend of the rare and the common, which allow an organism to survive. One of the most important of these conditions is climate – predictable ranges of temperature and humidity; another is the availability and flow of certain organic and non-organic nutrients.

Without a trace of the rare element phosphorus, for example, protein (based on abundant nitrogen) and carbohydrate polymers would not be possible.1  Without these proteins complex life forms as we know them would not exist.  Biodiversity is an expression of how living systems make effective use of these varied elements across the full spectrum of complexity, from genes to biomes.  It is biodiversity that allows one life form or another to thrive across most surfaces of the planet, and even survive the most extreme conditions on land, sea and in the atmosphere.



Biodiversity is thus an expression of nature’s problem solving capacities, demonstrating how to survive under varied conditions. A remarkable array of mechanisms has evolved allowing various life forms to flourish.  Just a few examples include:

 "If one could conclude as to the nature of the Creator from a study of his creation it 
  would appear that God has a special fondness for stars and beetles."  J.B.S.Haldane
A number of regularities regarding species size, metabolic rates and energy flows can be identified across species.3  But there is still debate about the role of biodiversity in terms of biomass productivity, a major indicator of species success.  In some biomes biodiversity is associated with greater productivity (e.g. tropical rain forests), and in other biomes with less (e.g. some extensive and ancient boreal forests, bogs and heathlands are not species rich but highly productive).  In still others there seems to be little if any relation.  Functional characteristics of the dominant species is sometimes more important than diversity, as with certain grasslands.4  In short, there is much we still do not know about the role of biodiversity in providing ecosystem services.

4. Biodiversity provides a large number of goods and services that sustain our lives. The benefits of biodiversity include:

The options value is of special significance as human activities alter many aspects of the natural world, including climate. Greater adaptability is going to be required because of these global changes, at a time when adaptability is declining due to biodiversity loss.

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biodiversity_ Number of estm species.png5. There are believed to be between 3 and 100 million species of plants and animals on earth. Estimates vary not only because experts use different methods of classification, but also because of considerable ignorance about just how many types of living things are in the world, and how they are connected. Scientists continue to discover new plant and animal species.










6. The current mass extinction, the only one induced by human activities, is believed to be approaching the largest in the history our planet. It is also occurring faster than any previous mass extinction, measurable in decades rather than in millions of years. We are currently loosing between 100 and 1000 times more species per year than the background extinction rate. On average, one extinction happens somewhere on earth every 20 minutes. If present trends continue, one half of all species on the planet will be extinct in 100 years.

Species extinction rates  fig  MEA.JPG
7. The major causes of species loss are urbanization, agriculture, invasive species, pollution, outdoor recreation/tourism, hunting, livestock and ranching activities, mining, industrial/military activity, water diversions, logging, harvesting/collecting, roads, genetic problems, wetland drainage/filling and aquifer depletion, and disease. Many of these causes are interconnected, and almost all can be traced to human economic activity5. The same causes threaten biodiversity from the molecular to the ecosystem level.

BIODIVERSITY THREATENED BY CLIMATE CHANGE.JPG8. Some of the newest threats to biodiversity are coming from human-induced global change processes such as climate change and atmospheric ozone depletion (see Climate Change, and Ozone). Recent studies suggest that by the middle of the century as many as one quarter of the species on the planet today, representing at least one million species, will be jeopardized by changes in climate stability already underway, unless climate change is reversed6.



9. In addition to losses through extinctions, major reductions in population size are also a serious threat to biodiversity. Significant reductions in population size reduce the opportunity to reproduce, genetic variability, and ecosystem function. Fewer numbers and reduced genetic variability in turn affect the species’ ability to survive changing environmental conditions. Species reduced to near their minimum viable populations may not ever recover.

The American Fisheries Society has recently released the first-ever list of marine fish stocks and species at risk of extinction. It identifies 82 species or populations vulnerable, threatened, or endangered in North American waters, including Atlantic Cod and Halibut. Twenty-two species are at risk globally.

10. Existing species can go extinct rapidly, but new species evolve at a very slow rate. Scientists have calculated from the fossil record that during periods of normal, or background, extinction, species loss occurs at an average of one every four years. It can take millions of years for new vertebrate species to emerge. By what we do or don't do in the next few decades, we will determine the future of evolution in terms of biodiversity composition for at least the next five million years, and in some respects, the next 10-15 million years.

11. Many species have thrived and survived for millions of years due to their abilities to out perform competitors in certain niches (e.g. some crocodile and shark species). Due to the tremendous breadth of the human niche, which expands with technological progress, the scale of the human economy is now expanding to the competitive exclusion of increasing numbers of other species. The current high rate of biodiversity loss is evidence of this human induced competitive exclusion.

12. Some examples of actual species loss include:

13. In addition to species that have already gone extinct, both the numbers of species at risk, and their level of risk, are increasing. Some examples include: 14. Some of the ecosystem services lost due to species extinctions include:
15. Various governments and international bodies have attempted to address biodiversity loss:

16. The many national and international agreements have been of questionable usefulness in protection overall biodiversity to date:

BOIDIVERSITY HOTSPOTS COLOR.JPG17. Recognizing the importance of biodiversity, and the difficulties inherent in preserving it, some groups have asked the question "which species are most important to save"? Various approaches have emphasized protection for keystone species, endangered species, or what are known as biodiversity hot spots – specific areas with exceptionally high densities of biodiversity. The dangers of attempting to set priorities for preservation efforts is that we are largely ignorant of the values any particular species provides to the web of life or the options value it might provide in a rapidly changing global environment.

18. Continued biodiversity loss threatens the web of life upon which humans depend. Global life support systems and biodiversity coevolved. The very atmosphere which makes the earth capable of supporting complex life forms was itself generated by plants and microbial organisms. Biodiversity depends on a complex interplay not only between living things and the natural world, but also amongst living creatures of varying forms and types, in ways we understand only vaguely. Ecosystem services provided by these complex global systems are essential for our quality of life as well as our survival. Biodiversity is essential for ecosystems to thrive and adapt to changing pressures from human activities. The less biodiversity there is and the more its natural composition is disrupted, the more the human enterprise is at risk.


1Deevey (1970) in Smil, Vaclav. Energy at the Crossroads: Global Perspectives and Uncertainties. Cambridge, MA: The MIT Press, 2003.

2Nabhan in Smil, Vaclav. Energy at the Crossroads: Global Perspectives and Uncertainties. Cambridge, MA: The MIT Press, 2003: 221.

3Tillman in Smil, Vaclav. Energy at the Crossroads: Global Perspectives and Uncertainties. Cambridge, MA: The MIT Press, 2003: 226.

4Smil, Vaclav. Energy at the Crossroads: Global Perspectives and Uncertainties. Cambridge, MA: The MIT Press, 2003: 199.

5 Czech. B. Shoveling Fuel for a Runaway Train: Errant Economists, Shameful Spenders, and a Plan to Stop Them All, University of California Press, Berkeley, 2000.

Czech, B. Economic growth as the limiting factor for wildlife conservation. Wildlife Society Bulletin, 2000, 28: 4-15.

Czech, B. and P.R. Krausman, Distribution and causation of species endangerment in the United States. Science, 1997, 227: 1116-1117.

 6Climate Change Forecast to Extinguish One Million Species                                                                        http://www.ens-newswire.com/ens/jan2004/2004-01-08-01.asp

 7The Convention on Biodiverisity  Convention Text. United Nations Environment Programme.

 8The Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES)
Text of the Convention. CITES Secretariat.
 9Cartagena Protocol on Biosafety
Text of Protocol. United Nations Environment Programme.

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