| Imbalance of Ecosystems and Its effect on
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| | cholera include explosive watery
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| Public and Livestock health
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| | diarrhea, vomiting, and abdominal pain.
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| Dr.Kedar Karki M.V.St. (Preventive
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| | The most recent pandemic of cholera
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| veterinary Medicine)
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| | involved more regions than at any
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| Central Veterinary Laboratory
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| | previous time in the twentieth century.
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| Tripureshwor
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| | The disease remains endemic in India,
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| The health of humans, like all living
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| | Bangladesh, and Africa. Vibrio cholerae
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| organisms, is dependent on an ecosystem
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| | has also been found in the United
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| that sustains life. Healthy ecosystems
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| | States-in the Gulf Coast region of Texas,
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| are the sine qua non for healthy
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| | Louisiana, and Florida; the Chesapeake
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| organisms. Yet there is abundant evidence
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| | Bay area; and the California coast.
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| that many life-support systems are far
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| | The increase in prevalence of V. cholerae
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| from healthy, placing an increased burden
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| | has been strongly linked to degraded
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| on human health. In some areas of the
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| | coastal marine environments.
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| world, gains in life expectancy and
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| | Nutrient-enriched warmer coastal waters,
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| quality of life made during the twentieth
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| | resulting from a combination of climate
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| century are at risk of being reversed in
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| | change and the use of fertilizers,
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| the twenty-first century. The
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| | provides an ideal environment for
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| consequences of ecosystem degradation to
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| | reproduction and dissemination of V.
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| human health are numerous, and include
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| | cholerae. Recent outbreaks of cholera in
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| health risks from unsafe drinking water,
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| | Bangladesh, for example, are closely
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| polluted air, climate change, emerging
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| | correlated with higher sea surface
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| new diseases, and the resurgence of old
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| | temperatures. V. cholerae attach to the
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| diseases owing to ecological imbalances.
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| | surface of both freshwater and marine
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| Reversing this damage is possible in some
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| | copepods (crustaceans), as well as to
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| cases, but not in others. Prevention of
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| | roots and exposed surfaces of macrophytes
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| ecological damage is by far the most
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| | (aquatic plants) such as the water
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| efficient strategy.
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| | hyacinth, the most abundant aquatic plant
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| DEFINING ECOSYSTEMS
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| | in Bangladesh. Nutrient enrichment and
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| An ecological system may be defined as a
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| | warmer temperatures give rise to algae
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| community of plants and animals
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| | blooms and an abundance of macrophytes.
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| interacting with each other and their
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| | The algae blooms provide abundant food
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| abiotic, or natural, environment.
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| | for copepods, and the increasing copepod
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| Typically, ecosystems are differentiated
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| | and macrophyte populations provide V.
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| on the basis of dominant vegetation,
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| | cholerae with habitat. Subsequent
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| topography, climate, or some other
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| | dispersal of V. cholerae into estuaries
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| criteria. Boreal forests, for example,
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| | and fresh water bodies allows contact
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| are characterized by the predominance of
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| | with humans who use these waters for
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| coniferous trees; prairies are
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| | drinking and bathing. Global distribution
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| characterized by the predominance of
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| | of marine pathogens such as V. cholerae
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| grasses; the Arctic tundra is determined
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| | is further facilitated by ballast water
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| partly by the harsh climatic zone. In
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| | discharged from vessels. Ballast water
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| most areas of the world, the human
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| | contains a virtual cocktail of pathogens,
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| community is an important and often
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| | including V. cholerae.
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| dominant component of the ecosystem.
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| | Two other examples of how ecological
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| Ecosystems include not only natural areas
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| | imbalances lead to human health burdens
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| (e.g., forests, lakes, marine coastal
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| | concern the increased prevalence of Lyme
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| systems) but also human-constructed
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| | disease and hantavirus pulmonary disease.
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| systems (e.g., urban ecosystems,
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| | Lyme disease, sonamed because it was
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| agro-ecosystems, impoundments). Human
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| | first positively identified in Lyme,
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| populations are increasingly concentrated
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| | Connecticut, is a crippling
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| in urban ecosystems, and it is estimated
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| | arthritic-type disease that is
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| that, by the year 2010, 50 percent of the
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| | transmitted by spirochete-infected Ixodes
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| world's population will be living in
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| | ticks (deer ticks). Ticks acquire the
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| urban areas.
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| | infection from rodents, and spend part of
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| A landscape comprises a mosaic of
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| | their life cycle on deer. Three factors
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| ecosystems, including towns, rivers,
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| | have combined to increase the risk to
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| lakes, agricultural systems, and so on.
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| | humans of contracting Lyme disease,
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| Precise boundaries between ecosystems are
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| | particularly in North America: (1) the
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| often difficult to establish. Often
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| | elimination of natural deer predators,
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| regions slide into one another gradually,
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| | particularly wolves; (2) reforestation of
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| over a protracted "transition" zone, as
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| | abandoned farmland has created more
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| for example between the boreal forest and
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| | favorable habitat for deer; and (3) the
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| the Taiga regions of Canada.
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| | creation of suburban estates, which the
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| ECOSYSTEM HEALTH
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| | deer find ideal habitat for browsing. The
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| It is important to recognize the inherent
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| | net result is a rising deer population,
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| difficulties in defining "health,"
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| | which increases the chances of humans
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| whether at the level of the individual,
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| | coming into more contact with ticks.
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| population, or ecosystem. The concept of
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| | By 1995, in the southwestern United
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| health is somewhat of an enigma, being
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| | States, hantavirus infection was
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| easier to define in its absence
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| | confirmed in ninety-four persons in
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| (sickness) than in its presence. Perhaps
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| | twenty states, with 48 percent mortality.
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| partially for that reason, ecologists
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| | Variants of the strain that causes
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| have resisted applying the notion of
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| | hantavirus pulmonary syndrome have also
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| "health" to ecosystems. Yet, ecosystems
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| | been found in other areas of the country,
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| can become dysfunctional, particularly
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| | as well as in Asia and Europe. The virus
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| under chronic stress from human
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| | is apparently asymptomatic in rodents,
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| activity.Example for this can be cited
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| | and it is transmitted in their saliva and
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| the discharge of nutrients from sewage,
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| | excreta. In humans it has a flu-like
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| industrial waste, or agricultural runoff
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| | presentation, which is followed by acute
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| into lakes or rivers affects the normal
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| | respiratory distress syndrome. The
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| functioning of the ecosystem, and can
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| | primary reservoir in the Four Corners
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| result in severe impairment. Excessive
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| | area of the southwestern United States is
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| nutrient inputs from human activity was
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| | the deer mouse. Climatic disturbances,
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| one of the major factors that severely
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| | which in recent years are thought to be
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| compromised the health of the lower
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| | exacerbated by human activity (e.g.,
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| Laurentian Great Lakes (Lake Erie and
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| | global warming), appear to set up
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| Lake Ontario) and regions of the upper
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| | conditions that trigger outbreaks. In the
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| Great Lakes (Lake Michigan).
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| | early 1990s, ENSO events initially caused
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| Unfortunately, degraded ecosystems are
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| | drought conditions to develop in the
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| becoming more the rule than the
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| | southwestern United States. This led to a
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| exception.
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| | decline in plant and animal populations,
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| The study of the features of degraded
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| | including natural predators of the deer
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| systems, and comparisons with systems
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| | mouse. Heavy rains followed the drought
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| that have not been altered by human
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| | in 1993, resulting in a bumper crop of
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| activity, makes it possible to identify
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| | piñon nuts, a major food supply for the
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| the characteristics of healthy
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| | deer mouse. Subsequently the deer mouse
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| ecosystems. Healthy ecosystems may be
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| | population greatly increased, bringing
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| characterized not only by the absence of
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| | about increased contact with humans and
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| signs of pathology, but also by signs of
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| | triggering the outbreak of hantavirus.
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| health, including measures of vigor
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| | Antibiotic Resistance and Agricultural
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| (productivity), organization, and
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| | Practice Antibiotic resistance is a
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| resilience.
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| | growing threat to public health.
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| Vigor can be assessed in terms of the
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| | Antibiotic resistant strains of
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| metabolism (activity and productivity) of
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| | Streptococcus pneumoniae, a common
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| the system. Ecosystems differ greatly in
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| | bacterial pathogen in humans and a
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| their normal ranges of productivity.
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| | leading cause of many infections,
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| Estuaries are far more productive than
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| | including chronic bronchitis, pneumonia,
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| open oceans, and marshes have higher
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| | and meningitis, have greatly increased in
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| productivity than deserts. Health is not
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| | prevalence since the mid-1970s. In some
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| evaluated by applying one standard to all
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| | regions of the world, up to 70 percent of
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| systems. Organization can be assessed by
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| | bacterial isolates taken from patients
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| the structure of the biotic community
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| | proved resistant to penicillin and other
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| that forms an ecosystem and by the nature
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| | b-lactam antibiotics. The use of large
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| of the interactions between the species
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| | quantities of antibiotics in agriculture
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| (both plants and animals). Invariably,
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| | and aquaculture appears to have been a
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| healthy ecosystems have more diversity of
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| | key factor in the development of
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| biota than ecologically compromised
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| | antibiotic resistance by pathogens in
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| systems. Resilience is the capacity of an
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| | farm animals that subsequently may also
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| ecosystem to maintain its structure and
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| | infect humans. One of the most serious
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| functions in the face of natural
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| | risks to human health from such practices
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| disturbances. Systems with a history of
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| | is vancomycin-resistant enterococci. The
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| chronic stress are less likely to recover
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| | use of avoparcin, an animal growth
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| from normal perturbations such as drought
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| | promoter, appears to have compromised the
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| than those systems that have been
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| | utility of vancomycin, the last
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| relatively less stressed.
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| | antibiotic effective against
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| Healthy ecosystems can also be
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| | multi-drug-resistant bacteria. In areas
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| characterized in economic, social, and
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| | where avoparcin has been used, such as on
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| human health terms. Healthy ecosystems
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| | farms in Denmark and Germany,
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| support a certain level of economic
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| | vancomycin-resistant bacteria have been
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| activity. This is not to say that the
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| | detected in meat sold in supermarkets.
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| ecosystem is necessarily self-sufficient,
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| | Avoparcin was subsequently banned by the
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| but rather that it supports economic
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| | European Union. Another example is the
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| productivity to enable the human
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| | use of ofloxacin to protect chickens from
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| community to meet reasonable needs.
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| | infection and thereby enhance their
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| Inevitably, ecosystem degradation
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| | growth. This drug is closely related to
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| impinges on the long-term sustainability
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| | ciprofloxacin, one of the most widely
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| of the human economy that is associated
| |
| | used antibiotics in the year 2000. There
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| with it, although in the short-term this
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| | have been cases of resistance to
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| may not be evident, as natural capital
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| | ciprofloxacin directly related to its
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| (e.g., soils, renewable resources) may be
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| | veterinary use. In the United Kingdom,
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| overexploited and temporarily enhance
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| | ciprofloxacin resistance developed in
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| economic returns. Similarly, with respect
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| | strains of campylobacter, a common cause
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| to social well-being, healthy ecosystems
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| | of diarrhea. Multi-drug-resistant strains
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| provide a basis for and encourage
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| | of salmonella have been traced to
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| community integration. Historically, for
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| | European egg production.
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| example, native Hawaiian groups managed
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| | Food and Water Security. Agricultural
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| their ecosystem through a well-developed
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| | practices are also responsible for a
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| social cohesiveness that provided a high
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| | growing number of threats to public
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| degree of cooperation in fishing and
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| | health. Some of these are related to
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| farming activity.
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| | inadequate waste management, which has
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| Another reflection of ecosystem health
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| | resulted in parasites and bacteria
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| lies directly in the public health
| |
| | entering water supplies. Others are of
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| domain. In spring 2000, a deadly strain
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| | entirely different origins and involve
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| of the bacterium E-coli (0157:H7) entered
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| | apparent transfer across species of
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| the public water supply in Walkerton,
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| | pathogens that affect both animals and
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| Ontario, Canada, causing seven deaths and
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| | humans. The most recent and spectacular
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| making thousands sick. This small town,
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| | example is mad cow disease, known as
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| with a population of five thousand, is in
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| | variant Creutzfeldt-Jakob disease in
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| a farming community. Inadequate manure
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| | humans, a neuro-degenerative condition
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| management from cattle operations was the
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| | that, in humans, is ultimately fatal. The
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| likely source of this tragedy.
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| | first case of Bovine Spongiform
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| HOW HEALTHY ECOSYSTEMS BECOME
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| | Encephalopathy (BSE), the animal form of
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| PATHOLOGICAL
| |
| | the disease, was identified in Southern
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| Stress from human activity is a major
| |
| | England in November 1981. By the fall of
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| factor in transforming healthy ecosystems
| |
| | 2000, an outbreak had also occurred in
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| to sick ecosystems. Chronic stress from
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| | France, and isolated cases appeared in
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| human activity differs from natural
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| | Germany, Switzerland, and Spain. More
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| disturbances. Natural disturbances
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| | than one hundred deaths in Europe were
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| (fires, floods, periodic insect
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| | attributed to what has come to be
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| infestations) are part of the dynamics of
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| | commonly called mad cow disease.
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| most ecosystems. These processes help to
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| | Improper manure management was the likely
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| "reset" ecosystems by recycling nutrients
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| | source of the outbreak of E. coli 0157:H7
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| and clearing space for recolonization by
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| | in Walkerton, Ontario, Canada. Other
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| biota that may be better adapted to
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| | health risks associated with
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| changing environments. Thus, natural
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| | malfunctioning agroecosystems include
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| perturbations help keep ecosystems
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| | periodic outbreaks of cryptosporidiosis,
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| healthy. In contrast, chronic and acute
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| | a parasitic disease that is spread by
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| stress on ecosystems resulting from human
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| | surface runoff contaminated by feces of
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| activity (e.g., construction of large
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| | infected cattle. This parasite causes
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| dams, release of nutrients and toxic
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| | fever and diarrhea in immunocompetent
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| substances into the air, water, and land)
| |
| | individuals and severe diarrhea and even
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| generally results in long-term ecological
| |
| | death in immunocompromised individuals.
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| dysfunction.
| |
| | ECOSYSTEM RESTORATION
|
| Five major sources of human-induced
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| | Ecosystem pathology in some cases can be
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| (anthropogenic) stresses have been
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| | reversed simply by removing the source of
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| identified by D. J. Rapport and A. M.
| |
| | stress. In cases, for example, where
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| Friend (1979): physical restructuring,
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| | ecosystem degradation is the result of
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| overharvesting, waste residuals,
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| | point-source additions of nutrients or
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| introduction of exotic species, and
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| | toxic chemicals, removal of these
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| global change.
| |
| | stresses may result in considerable
|
| Physical Restructuring. Activities such
| |
| | recovery of ecosystem health. A classic
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| as wetland drainage, removal of shoals in
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| | case is Lake Washington (near Seattle,
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| lakes, damming of rivers, and road
| |
| | Washington). This lake had become highly
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| construction fragment the landscape and
| |
| | anoxic (oxygen-depleted) owing to a
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| alter and damage critical habitat. These
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| | sewage outfall entering the lake.
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| activities also disrupt nutrient cycling,
| |
| | Redirecting the sewage outfall away from
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| and cause the loss of biodiversity.
| |
| | the lake reversed many of the signs of
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| Overharvesting. Overexploitation is
| |
| | pathology.
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| commonplace when it comes to harvesting
| |
| | In cases where it is not feasible to
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| of wildlife, fisheries, and forests. Over
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| | remove the source of stress, more
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| long periods of time, stocks of preferred
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| | innovative engineering solutions have
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| species are reduced. For example, the
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| | been tried. For example, in the
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| giant redwoods that once thrived along
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| | Kyrönjoki and Lestijoki Rivers in
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| the California coast now exist only in
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| | western Finland, spring and fall runoff
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| remnant patches because of
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| | leads to sharp pulses of acidity. Spring
|
| overharvesting. When dominant species
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| | runoff from snowmelt, which releases acid
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| like the giant redwoods (arguably the
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| | from tilled or dug soils, has been
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| world's tallest tree-one specimen was
| |
| | particularly damaging to fish, during the
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| recorded at 110 meters tall with a
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| | critical time of year for spawning. Fish
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| circumference of 13.4 meters) are lost,
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| | reproduction is severely curtailed, if
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| the entire ecosystem becomes transformed.
| |
| | not all together eliminated in highly
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| Overharvesting often results in reduced
| |
| | acidic water. Further there have been
|
| biodiversity of endemic species, while
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| | massive fish kills resulting from the
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| facilitating the invasion of
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| | highly acidic waters. One possible remedy
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| opportunistic species.
| |
| | is to replace the original drains which
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| Waste Residuals. Discharges from
| |
| | take runoff from the land to the rivers
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| municipal, industrial, and agricultural
| |
| | with new limed drains that can neutralize
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| sources into the air, water, and land
| |
| | the acidity. This solution has been
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| have severely compromised many of the
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| | implemented on an experimental basis and
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| earth's ecosystems. The effects are
| |
| | appears to substantially reduce acidic
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| particularly apparent in aquatic
| |
| | runoff.
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| ecosystems. In some lakes that lack a
| |
| | More radical treatments for damaged
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| natural buffering capacity, acid
| |
| | ecosystems involve "ecosystem surgery."
|
| precipitation has eliminated most of the
| |
| | In some cases, invading exotic vegetation
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| fish and other organisms. While the
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| | (such as mangroves in Hawaii) have been
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| visual effect appears beneficial (water
| |
| | removed from regions, and native
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| clarity goes up) the impact on ecosystem
| |
| | vegetation has been replanted. In areas
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| health is devastating. Systems that once
| |
| | of North America where wetlands have been
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| contained a variety of organisms and were
| |
| | severely depleted owing to farming,
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| highly productive (biologically) become
| |
| | urbanization, and industrial activity,
|
| devoid of most lifeforms except for a few
| |
| | efforts have been made to establish new
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| acid-tolerant bacteria and
| |
| | wetlands.
|
| sediment-dwelling organisms.
| |
| | More often than not, however, reversing
|
| Introduction of Exotic Species. The
| |
| | ecosystem pathology is not possible.
|
| spread of exotics has become a problem in
| |
| | Efforts to restore the indigenous
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| almost every ecosystem of the world.
| |
| | grasslands in the Jornada Experimental
|
| Transporting species from their native
| |
| | Range in the southwestern United States
|
| habitat to entirely new ecosystems can
| |
| | provide an example. Overgrazing by cattle
|
| wreck havoc, as the new environments are
| |
| | has severely degraded the landscape and
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| often without natural checks and balances
| |
| | has lead to replacement of the native
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| for the new species. In the Great Lakes
| |
| | grasses by largely inedible shrubs,
|
| Basin, the accidental introduction of two
| |
| | dominated by mesquite. Erosion by wind
|
| small pelagic fishes, the alewife and the
| |
| | and episodic heavy rains have left areas
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| rainbow smelt, combined with the
| |
| | between shrubs largely bare, and
|
| simultaneous overharvesting of natural
| |
| | subsequently underlying sands have
|
| predators, such as the lake trout, led to
| |
| | developed in dune-like fashion over a
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| a significant decline in native fish
| |
| | large part of the area. The resulting
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| species. The introduction of the sea
| |
| | mesquite dunes have proven highly
|
| lamprey, an eel-like predacious fish that
| |
| | resistant to efforts to restore the
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| attacks larger fish, into Lake Erie and
| |
| | native grasslands, although almost every
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| the upper Great Lakes further
| |
| | intervention has been tried, including
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| destabilized the native fish community.
| |
| | highly toxic defoliants (Agent Orange),
|
| The sea lamprey contributed to the demise
| |
| | fire, and bulldozing.
|
| of the deepwater benthic fish community
| |
| | Even where it has been possible to
|
| by preying on lake trout, whitefish, and
| |
| | restore some of the ecological functions
|
| burbot. This contributed to a shift in
| |
| | of degraded ecosystems, and thus improve
|
| the fish community from one that had been
| |
| | ecosystem health, the restoration seldom
|
| dominated by large benthics to one
| |
| | results in reestablishment of the
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| dominated by small pelagics (fish found
| |
| | pristine biotic community. The best that
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| in the upper layers of the lake profile).
| |
| | can be achieved in most cases is
|
| This shift from bottom-dwelling fish
| |
| | reestablishment of the key ecological
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| (benthic) to surface-dwelling fish
| |
| | functions that provide the required
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| (pelagic) has now been partially reversed
| |
| | ecosystem services, such as the
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| by yet another accidental introduction of
| |
| | regulation of water, primary and
|
| an exotic: the zebra mussel. As the zebra
| |
| | secondary productivity, nutrient cycling,
|
| mussel is a highly efficient filter of
| |
| | and pollination. In all such efforts, key
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| both phtyoplankton and zooplankton, its
| |
| | indicators of ecosystem health (vigor,
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| presence has reduced the available food
| |
| | productivity, and resilience) are
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| in the surface waters for pelagic fish.
| |
| | essential to monitor progress. Standard
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| However, while the benthic fish community
| |
| | ecological indicators can be used for
|
| has gained back its dominance, the
| |
| | this purpose (e.g., measures of
|
| preferred benthic fish species have not
| |
| | productivity, species composition,
|
| yet recovered owing to the degree of
| |
| | nutrient flows, soil fertility) along
|
| initial degradation. Overall, the
| |
| | with socioeconomic and human health
|
| increasing dominance by exotics not only
| |
| | indicators.
|
| altered the ecology, but also reduced
| |
| | Experience in efforts to restore highly
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| significantly the commercial value of the
| |
| | damaged ecosystems suggests that
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| fisheries.
| |
| | ecosystem-health prevention is far more
|
| Global Change. Rapid climate change (or
| |
| | effective than restoration. For marine
|
| climate warming) is an emerging potential
| |
| | ecosystems, setting aside protective
|
| global stress on all of the earth's
| |
| | zones that afford a sanctuary for fish
|
| ecosystems. In evolutionary time, there
| |
| | and wildlife has considerable promise.
|
| have of course been large fluctuations in
| |
| | Many countries are adopting policies to
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| climate. However, for the most part these
| |
| | establish such areas with the prospect
|
| fluctuations have occurred gradually over
| |
| | that these healthy regions can serve as a
|
| long periods of time. Rapid climate
| |
| | reservoir for biota that have become
|
| change is an entirely different matter.
| |
| | depleted in the unprotected areas. Yet
|
| By altering both averages and extremes in
| |
| | this remedy is not without its limits.
|
| precipitation, temperature, and storm
| |
| | Restoring ecosystem health is not simply
|
| events, and by destabilizing the El Niño
| |
| | a matter of replenishing lost or damaged
|
| Southern Oscillation (ENSO), which
| |
| | biota. It is also a matter of
|
| controls weather patterns over much of
| |
| | reestablishing the complex interactions
|
| the southern Pacific region, many
| |
| | among ecosystem lifeforms. Having a ready
|
| ecosystem processes can become
| |
| | source of healthy biota that could
|
| significantly altered. Excessive periods
| |
| | potentially recolonize damaged ecosystems
|
| of drought or unusually heavy rains and
| |
| | is important, but it is only part of the
|
| flooding will exceed the tolerance for
| |
| | solution.
|
| many species, thus changing the biotic
| |
| | PREVENTION OF ECOSYSTEM DISRUPTIONS
|
| composition. Flooding and unusually high
| |
| | Given the difficulties in reversing
|
| winds contribute to soil erosion, and at
| |
| | ecosystem degradation, and the many
|
| the same time add to nutrient load in
| |
| | associated human health risks that arise
|
| rivers and coastal waters.
| |
| | with the loss of ecosystem health, the
|
| These anthropogenic stresses have
| |
| | most effective approach is simply the
|
| compromised ecosystem function in most
| |
| | prevention of ecosystem disruption.
|
| regions of the world, resulting in
| |
| | However, like many common-sense
|
| ecosystem distress syndrome (EDS). EDS is
| |
| | approaches, this is easier said than
|
| characterized by a group of signs,
| |
| | done. In both developed and developing
|
| including abnormalities in nutrient
| |
| | countries there is a strong inclination
|
| cycling, productivity, species diversity
| |
| | to continue economic growth, even at the
|
| and richness, biotic structure, disease
| |
| | cost of severe environmental damage.
|
| prevalence, soil fertility, and so on.
| |
| | Apart from selfish motivations, the
|
| The consequences of these changes for
| |
| | argument is made that economic growth has
|
| human health are not inconsiderable.
| |
| | many obvious health benefits, such as
|
| Impoverished biotic communities are
| |
| | providing more efficient means of
|
| natural harbors for pathogens that affect
| |
| | distributing food supplies, providing
|
| humans and other species.
| |
| | more plentiful food, and providing better
|
| ECOSYSTEM HEALTH AND HUMAN HEALTH
| |
| | health services and funding for research
|
| An important aspect of ecosystem
| |
| | to improve standards of living. These are
|
| degradation is the associated increased
| |
| | indeed benefits of economic development,
|
| risk to human health. Traditionally, the
| |
| | and have led to substantial increases in
|
| concern has been with contaminants,
| |
| | health status worldwide.
|
| particularly industrial chemicals that
| |
| | However, at the dawn of the twenty-first
|
| can have adverse impacts on human
| |
| | century, the past is not necessarily the
|
| development, neurological functions,
| |
| | best guide to the future. The human
|
| reproductive functions, and that appear
| |
| | population is at an all-time high, and
|
| to be causative agents in a variety of
| |
| | associated pressures of human activity
|
| carcinomas. In addition to these serious
| |
| | have led to increasing degradation of the
|
| environmental concerns (where the
| |
| | earth's ecosystems. As ultimately healthy
|
| remedies are often technological,
| |
| | ecosystems are essential for life of all
|
| including engineering solutions to reduce
| |
| | biota, including humans, current global
|
| the release of contaminants), there are a
| |
| | and regional trends are ominous. Under
|
| large number of other risks to human
| |
| | these circumstances, a tradeoff between
|
| health stemming from ecological
| |
| | immediate material gains and long-term
|
| imbalance.
| |
| | sustainability of humans on the planet
|
| Ecosystem distress syndrome results in
| |
| | may be the only option. If so, the
|
| the loss of valued ecosystem services,
| |
| | solution to sustaining human health and
|
| including flood control, water quality,
| |
| | ecosystem health becomes one of devising
|
|