Transcript Ecosystem Services - Philosophy Department

Ecosystem Services
• Biodiversity
• Climate
• Mitigation of floods and
droughts
• Services provided by
soil
• Pollination
• Pest control
• Seed dispersal
• Aesthetic beauty
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BIOSPHERE 2
Biosphere 2
• 3.15-acre artificial closed
ecological system outside Tucson
• It included a rainforest, mini-ocean,
coral reef, mangrove wetlands,
savannah grassland, desert, farm,
and living quarters and offices
• First mission: 9-26-1991 to 9-261993, 8 people
• Second mission: 3-6-94 to 9-6-94,
aborted
Problems
• Despite $200 million invested,
impossible to sustain the 8
people without continual help
from the outside.
– O2 concentration dropped to 14%
– Spikes in CO2
– Nitrous oxide concentrations high
enough to cause brain damage
– Extinctions (19/25 vertebrates, all
pollinators)
– Wild overgrowth of vines and
various insect populations
Both missions, and especially the
second, experienced many, many social
and organizational problems.
“Overriding scientific lessons from Biosphere 2 already may be
available. To many of us, healthy ecosystems and biodiversity
have inestimable aesthetic value, but such philosophical
orientations are difficult to translate into the kinds of economic
terms that carry weight with business or industrial interests.
Some far-thinking economists have sought to attach dollar
values to natural ecosystems by virtue of the fundamental lifesupport services rendered (e.g., atmospheric regulation by
rainforests and oceans, water purification by marshes,
groundwater storage by aquifers, soil generation and
maintenance by decomposers), but such at- tempts are almost
hopelessly complicated by the vast range of spatial and
temporal scales over which the monetary valuations might be
tabulated. However, thanks to the controlled experiment of
Biosphere 2 we now have a more explicit ledger. ..
…”The cost of the man-made technosphere that (marginally)
regulated life-support systems for eight Biospherians over two
years was about $150 million, or $9,000,000 per person per
year. These services are pro- vided to the rest of us more-orless cost-free by natural processes, but if we were being
charged, the total invoice for all Earthospherians would come to
an astronomical three quintillion dollars for the current generation alone! The sad irony is that, as a species, we blithely take
these eco- system services for granted, acting as though we can
endlessly befoul and overpopulate our planet.”
--John Avise, “The Real Message From Biosphere 2”
The problem
It’s widely agreed
that there is a
biodiversity crisis.
Legislation and
treaties are enacted
to help stop it. But
what is biodiversity,
and why do we value
it? Should we value
it?
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• Endangered Species Preservation Act, 1966:
required a list to be made of endangered species and
money to be set aside for purchase of habitat to
protect them--but no provisions included against
harming endangered animals.
• Endangered Species Conservation Act, 1969:
required two lists, of foreign and of native,
endangered species; foreign species on the list were
not allowed into the country, and species native or
foreign could not be bought or sold if illegally taken.
“The stated purposes of the ESA are: “to provide a means whereby the
ecosystems upon which endangered species and threatened species depend
may be conserved, to provide a program for the conservation of such
endangered species and threatened species, and to take such steps as may
be appropriate to achieve the purposes of the treaties and conventions [on
international trade in endangered species] (Sec. 2(b)).
Certainly the best-known impact of the ESA is the establishment of broad
prohibitions against any take of endangered and threatened animal species.
However, another major intention of the act is to integrate federal and
international legislation on endangered species, including the national-level
implementation of CITES (Convention on International Trade in Endangered
Species of Wild Flora and Fauna, 1973). Within this structure, the ESA
establishes guidelines to define categories and listing protocols for
endangered and threatened species (Sec. 4). In addition, the act defines the
concept of "critical habitat". Federal agencies are required to (a) actively
promote the conservation of listed species; and (b) avoid any actions that
would have negative effects on listed species and their critical habitat. Finally,
the ESA provides matching federal funds for some state actions in support of
the act and authorizes the acquisition of land for plants and animals listed
under CITES.”
Endangered Species Act 1973
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gives the FWS and NMFS authority to list species
that are either "endangered" or "threatened" (likely
to become endangered in the foreseeable future),
requires that federal agencies and departments
through their own actions or actions funded or
permitted by them must not jeopardize the
continued existence of a listed species or its
habitat,
declares it unlawful to "take" an endangered or
threatened species within the U.S., its territorial
waters, or on the high seas,
provides Interior and Agriculture with authority
and funds to acquire habit of endangered or
threatened species,
provides for criminal penalties, including seizure
of equipment used in takings, and
provides standing to citizens to bring suit under the
ESA.
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Endangered Species Act 1973
(Go to ESA pdf…)
How does a species get listed as an
endangered or threatened species?
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First, the public, the Fish and Wildlife
Service, biologists, or other governmental
agencies, propose a species for the list.
The public is offered the opportunity to
comment about the proposal, and the rule
is finalized (or withdrawn).
Species to be listed are selected by the
Fish and Wildlife Service from a list of
candidates and are recognized using a
priority system.
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Bald Eagle (increased from 417 to 9,250 pairs between 1963 and 2006)
Whooping Crane (increased from 54 to 436 birds between 1967 and 2003)
Kirtland's Warbler (increased from 210 to 1,415 pairs between 1971 and 2005)
Peregrine Falcon (increased from 324 to 1,700 pairs between 1975 and 2000)
Gray Wolf (populations increased dramatically in the Northern Rockies, Southwest,
and Great Lakes)
Gray Whale (increased from 13,095 to 26,635 whales between 1968 and 1998)
Grizzly bear (increased from about 271 to over 580 bears in the Yellowstone area
between 1975 and 2005).
Californiaﾕs Southern Sea Otter (increased from 1,789 in 1976 to 2,735 in 2005)
San Clemente Indian Paintbrush (increased from 500 plants in 1979 to more than
3,500 in 1997)
Florida's Red Wolf (increased from 17 in 1980 to 257 in 2003)･
Few species have become extinct while listed under the Endangered Species Act, and
93% have had their population sizes increase or remain stable since being listed as
threatened or endangered. Currently 1,312 species are listed.
• As of today in the United States there are 92 listed
endangered species (357 animals and 567 plants).
• There is a total of 256 listed threatened species in the
United States (121 animals and 135 plants).
• Of the 924 endangered species in the United States,
70 are endangered and 40 are threatened species of
fish.
• Plants represent the largest group, followed by birds,
fishes, mammals, and clams/mussels.
Controversy
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Tennessee Valley Authority v. Hill, 437 U.S. 153 (1978).
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A project that had already progressed substantially before the discovery of a listed species
on the site eventually led to amendments to the ESA and associated regulations and to the
creation of the Endangered Species Committee and an exemption process from section 7.
More directly, this ruling determined that the TVA’s ignorance of the existence of the species
at the project site did not excuse it from following the protocols required by the ESA; in
addition, the idea that economic factors might be taken into account in complying with the
ESA was flatly rejected, as was the idea that continued congressional funding of a project
effectively exempted the project from ESA compliance.
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Babbitt v. Sweet Home Chapt. Comms. for Ore., 515 U.S. 687 (1995)
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The Supreme Court found that in addition to making it a crime to "take" a listed species,
section 9 also prohibits the destruction of habitat of such a species. The legislative
definitions of "take" and "harm" are sufficiently broad to include the degradation or
destruction of a species’ habitat.
• A species is "any subspecies of fish or
wildlife or plants, and any distinct
population segment of any species of
vertebrate fish or wildlife which
interbreeds when mature." 16 U.S.C.
§ 1532(16).
• http://www.mrsc.org/environment/esa/esa
prime.htm (explains ESA)
• http://endangered.fws.gov/esa.html
(statement of ESA)
• 99% of the time the Government has
found (in over 120,000 consultations) the
species of concern was not in jeopardy.
• There are about 632 officially endangered
species (326 plants) and 190 threatened
species in the U.S.
What is a Species?
• We want to know what to
worry about, what to
conserve. The mallard
duck was introduced into
Australia and New
Zealand. It mates with the
native Pacific grey drakes.
Because more aggressive
and adaptable, the mallard
may eliminate the Pacific
grey drake as a distinctive
duck. Is this bad?
Taxonomy
Taxonomy: species (sapiens), genus (Homo), family (hominid), order
(primates), class (mammal), phylum (chordate), kingdom (animal)
1.
phenetic species concept: a measure of morphological, genetic or
behavioral similarity. Species are groups of similar organisms.
Makes species a conventional distinction
Males, females, juveniles may differ markedly in appearance/behavior
2.
biological species concept: a species is a group wherein genes flow
freely. If X and Y are two species, X is reproductively isolated from Y.
The notion of potentially interbreeding is slippery
3.
phylogenetic species concept: a species is a lineage of
ancestral/descendant population.
How do we count lineages?
Both 2 and 3 are “historical” definitions. No intrinsic property makes you or
anything a member of a species.
Problem
1.5 million species have been
catalogued. It is thought that
there are currently 10 and 100
million that exist on Earth.
• Between 1600 and 1900: one
species goes extinct per 4 yrs
• Between 1900 and 1960: one
species goes extinct per 1 yr
• Between 1960 and now:
estimates vary from 100 per yr
to 40,000 per yr!
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• Amazon: 2.7 million square miles (about 90% size of continental
U.S.). The Amazon River is 4000 miles long and puts 170 billion
gallons of water into the Atlantic per hour. In a small area of the forest
one might find: 750 tree species, 125 mammal species, 400 bird
species, 60 amphibian species, and 400 insect species (in just one tree).
30% of all the world’s bird species are here.
• Terry Erwin’s “bug bomb” gave estimates of 8 million types of beetle
and 30 million species of tropical arthropods in one small area.
• Hawaii: since first human contact, as many as half of the birds have
gone extinct. Out of 135 current species of bird, only about a dozen
are doing well. Another dozen are virtually extinct, another dozen
endangered.
• 80,000 acres square miles of forest lost each yr (World Resources
Institute; U.N.)
• In U.S. the National Biological Service (Feb 1995) reported that during
last century half of our country’s ecosystems had been degraded to the
point of endangerment.
• There exist various models (e.g., by MacArthur and Wilson, Harvard,
1963) that allow one to predict the effect on species of deforestation.
Assuming the number of species doubles with every tenfold increase in
area, reducing tropical forests to 10% of what they were will reduce 50%
of the earth’s species. Estimated 17,000 – 100,000 species per yr lost
• “Homo sapiens is poised to become the greatest catastrophic agent since
a giant asteroid collided with the earth sixty-five million years ago,
wiping out half the world’s species in a geological instant.” (Richard
What is a Species?
• “(15) The term "species" includes any subspecies of fish or
wildlife or plants, and any distinct population segment of any
species or vertebrate fish or wildlife which interbreeds when
mature.”
•Typological/morphological speciesﾊA group of
organisms in which individuals are members of the species
if they sufficiently conform to certain fixed properties. The
clusters of variations or phenotypes within specimens (ie:
longer and shorter tails) would differentiate the species. This
method was used as a "classical" method of determining
species, such as with Linnaeus early in evolutionary theory.
However, we now know that different phenotypes do not
always constitute different species (e.g.: a 4-winged
Drosophila born to a 2-winged mother is not a different
species). Species named in this manner are called
morphospecies.
•
Biological / Isolation speciesﾊA set of actually or potentially
interbreeding populations. This is generally a useful formulation for
scientists working with living examples of the higher taxa like mammals,
fish, and birds, but meaningless for organisms that do not reproduce
sexually. It does not distinguish between the theoretical possibility of
interbreeding and the actual likelihood of gene flow between
populations and is thus impractical in instances of geographically
isolated populations.
•
Phylogenetic / Evolutionary / Darwinian speciesﾊA group of
organisms that shares an ancestor; a lineage that maintains its integrity
with respect to other lineages through both time and space. At some
point in the progress of such a group, members may diverge from one
another: when such a divergence becomes sufficiently clear, the two
populations are regarded as separate species. Subspecies as such are
not recognized under this approach; either a population is a
phylogenetic species or it is not taxonomically distinguishable.
Biological Species Concept
The biological species concept defines a species as
members of populations that actually or potentially
interbreed in nature, not according to similarity of
appearance. Although appearance is helpful in
identifying species, it does not define species.
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Appearance isn’t everything
Organisms may appear to be alike and be
different species. For example, Western
meadowlarks (Sturnella neglecta) and Eastern
meadowlarks (Sturnella magna) look almost
identical to one another, yet do not interbreed
with each other—thus, they are separate
species according to this definition.
The Western meadowlark and the Eastern meadowlark
appear to be identical, and their ranges overlap, but their
distinct songs prevent interbreeding.t interbreeding.
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Organisms may look different and yet
be the same species. For example,
look at these ants. You might think
that they are distantly related species.
In fact, they are sisters—two ants of
the species Pheidole barbata, fulfilling
different roles in the same colony.
Many characteristics can vary within a
single species. For example, the plant
hydrangea may have pink “flowers”—
they’re actually modified leaves—or
blue “flowers.” But that doesn’t mean
that we should classify the two forms
as different species. In fact, you could
cause a blue-“flowered” plant to
become a pink-“flowered” plant just by
changing the pH of the soil and the
amount of aluminum taken up by the
plant.
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The Crisis
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• Ranges of current extinctions
are 100–10,000 times the
prehuman level of roughly
one species out of a million
each year. Most estimates
are closer to 1,000 times the
prehuman level (equal to
0.1% per year or 5% over 50
years), but the rate is rising.
In The Diversity of Life, E.O. Wilson uses conservative values to scale
species loss to area reduction and the rate of tropical deforestation.
He arrives at about 0.25% of tropical forest species extinguished or
committed to early extinction annually (Wilson 1999, p. 280). Since
most species likely occur in tropical forests, these ecosystems are a
good proxy: even if no extinction occurred elsewhere, the planetary
rate would still be 1,000 times prehuman levels. (What do we mean by
ﾒcommitted to early extinctionﾓ? Studies from forests show that when
forests are reduced to even large fragments, then 10ﾐ50% of the
species go extinct within 100 years (see footnote above). The areadependent decline in mammal species in national parks also accords
with the picture of committed extinction by a real reduction alone
(Newmark 1996) .
Species-Area Curve
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