BIOL 4P08 Lecture Notes - Ecosystem Management, Soil Retrogression And Degradation, Overfishing

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What Services Do Ecosystems Provide?
Many benefits are irreplaceable or the technology necessary to replace
them are very expensive
potable fresh water can be provided by desalinating seawater but only
at a great cost
rapidly expanding human population has modified Earth's ecosystems to
increase their ability to provide some of the goods and services it needs
these modifications have contributed to human well-being and
economic development
short-term increases in some ecosystem goods have come at the cost of the
long-term degradation of others
efforts to increase wood and fiber have decreased the ability for some
ecosystems to provide clean water, regulate flooding and support
the spread of agriculture into into marginal lands has increased soil
degradation and reduced ability of ecosystems to provide clean water
pesticides reduces populations of pollinators
damage from tsunami of 2004 would have been less if the mangrove
forests that protect the coasts had had not been cut down
Hurricane Katrina would not have caused as much flooding if the
wetlands surrounding area had been left intact
Millennium Ecosystem Assessment – a project that involved more than a
thousand scientists and managers worldwide to provide a global
assessment of Earth's ecosystems, determine trends in the services they
provide and assess their importance to human well-being
divided ecosystem services into 4 categories: provisioning services,
regulating services, cultural services, supporting services
most important driver of alterations in ecosystems has been changes in
land use as natural ecosystems have been converted to other more
intensive uses
more land was converted to crop land from 1950-1980 than from 1700-1850
conversions in tropical and subtropical terrestrial ecosystems have been
particularly rapid
from 1970-2000, about 20% of coral reefs were lost and another 20% were
6 times as much water is held in reservoirs then in natural rivers
amount of water withdrawn from rivers has doubled
food production contributes the most to economic development and
22% of of world's population is employed in agriculture
40% live in agriculturally based households
What Options Exist To Manage Ecosystems Sustainably?
Total economic value of a sustainably managed ecosystem is higher than
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