Download 08 D human impact, conservation

Human Impact and Conservation
- The human population
- Biodiversity
- Alien species
- Pollution
- Problems with the ozone layer
- Global warming
- Extinctions
- Resource management
- Conservation
Chapter 16 in the text
The human population
For most of man’s time on Earth, K was rather stable:
natality about equaled mortality.
www.biology.iupui.edu/.../n100/2k4ch39pop.html
Note: apparent causes of change in K (agricultural revolution, industrial age)
Estimated population 11/2008: 6.7 billion
… another graphic.
www.theglobaleducationproject.org/earth/human...
note: Asia has the largest percentage of the population,
but not the highest growth rate.
Demographics: An age-structure diagram is a snapshot
of a population’s age distribution:
It can help predict what future population trends might arise.
e.g., How many are approaching child-bearing age?
How many are approaching retirement?
It does NOT illuminate cause and effect.
Things that have been linked to a slowing in regional population size increase:
Increased education. Women’s entrance into the workforce.
Improved economic opportunities. Decisions about social responsibility.
-Biodiversity
Human impact tends to reduce the diversity of living things:
genetic diversity: the genetic pool for a species
is reduced as populations die off.
- Florida panther
- genes to enrich agricultural stock
species diversity, or species richness: number of species,
reflects a healthy community.
- impact of introduced species
- importance to food web resiliency
Richness reflects the variety of species.
Evenness reflects how the numbers are distributed
among the species.
ecosystem diversity: variety of ecosystems
One ecosystem influences the next.
- impact of carbon-sequestering by seas
- marsh filtration and buffering roles
Why do we care about biodiversity?
Ethics
Ecology
Economics
Aesthetics
(hoatzins↑)
1. Economic and aesthetic reasons can lead
← to deliberate introductions:
e.g. kudzu for flowers, forage, erosion
control, camouflage in Vanuatu…
2. Many invasive
species come
uninvited, as in
ships’ tanks:
e.g. zebra mussel
→
http://www.nysaes.cornell.edu/ent/biocontrol/info/biocont.html
- Alien species, or introduced species
-Not all introduced species are invasive (goldfish),
but many are, when they aren’t constrained by natural balances.
3. Biological control of pests ↑ :
e.g. a European parasitoid wasp
imported, quarantined, cultivated
and released, to control the
southern stink bug (from Ethiopia).
- Litter
This preserve is about as far from anywhere as you can get.
Boaters are not allowed to land without permits.
Litter (cont.)
http://knowledge.allianz.com/nopi_downloads/images/pacific_ocean_garbage_patch_pollution_plastic_junk_beach_hawaii_q.jpg
http://eicolab.com.au/wp-content/uploads/2007/09/albaplast.jpg
Chemical pollution:
- Many noxious things have been dumped
http://walrus.wr.usgs.gov/farallon/radwaste.html
without regard to possible consequences:
e.g. 47,800 barrels of low-level nuclear waste
dumped off San Francisco 1946-1970, in the
Farallones Marine Reserve. They are
now trying to find them….
Many materials have become more toxic within the environment Biomagnification: the concentration of chemicals
within the food web.
http://www.usgs.gov/themes/factsheet/146-00/
- DDT (insecticide; accumulates in
fish-eating birds; sabotages eggs)
- mercury (atmospheric from coal burning,
metal processing, others; methylated
by bacteria, as in the Everglades;
nerve and birth defects.)
(Activity on page 153 in text to demonstrate)
Ozone (O3)
- is made by lightning (causing a characteristic smell).
- forms at low altitude indirectly from car exhaust, adding to smog.
- absorbs UV light.
There is an ozone layer in the stratosphere (about 20 km up),
which is very important to protect life from UV damage. (such as?)
CFCs (chlorofluorocarbons)
used as aerosol propellants and coolants
waft up to the stratosphere, where they split ,
and the Cl catalytically coverts O3 into O2,
creating a hole in the ozone layer,
increasing Earth’s surface exposure to UV.
- Montreal protocol (1987)
(it may take 50 – 100 years for the CFCs to decline)
(Without it the
average
temperature
would be about
30oC colder,
with huge
fluctuations.)
Global warming
is the unnatural
amplification of this
effect.
www.coolwilliamstown.org/what_is.php
The
greenhouse effect
is a natural
mechanism,
essential
to life on Earth.
- Petroleum passed coal
as a source of carbon
emissions in the 60s,
as interstates were built.
- Natural gas burns
cleaner than coal, but it
is still a hydrocarbon.
- Cement production?
5% of anthropogenic CO2,
from calcification of
limestone, kilns, and
power generation.1
1 Abstract
Annual Review of Energy and the Environment
Vol. 26: 303-329 (Volume publication date November 2001)
(doi:10.1146/annurev.energy.26.1.303)
CO2 is among several compounds in the atmosphere
that reduce the amount of solar thermal energy that rebounds.
It is not the most potent of these.
It is the one on which mankind has had the strongest impact.
U.S. Anthropogenic Greenhouse
Gas Emissions by Gas,
2006 (Million Metric Tons of
Carbon Dioxide Equivalent)
- Methane and nitrous oxides
are also key components.
- HFCs were made to replace
CFCs.. but trap heat!
- SF6 is far more potent at
trapping heat than CO2,
and is all synthetic.
http://www.eia.doe.gov/bookshelf/brochures/greenhouse/Chapter1.htm
- Water vapor also traps heat,
and is increasing with
rising temperatures, but
increased clouds may reflect
more radiation…
http://www.esrl.noaa.gov/gmd/ccgg/trends/
←This is probably a familiar
graphic.
Longer term
correlation of CO2
levels to
temperature.→
What factors lead to extinctions?
- Habitat loss
due to development, fragmentation, etc.
- Deliberate hunting
as a perceived pest or for exploitation
- Loss of requisite community members
butterflies and chestnuts, for example
- Competition
as from invasive species, e.g. Hawaii
- Natural extinctions
Geologic areas may be defined by mass extinctions
(e.g. meteorite in Cretaceous caused the 5th great die off)
“…today we are experiencing a mass extinction comparable to that of the dinosaurs
where nearly 20 plant and animal species become extinct every hour.” *
Can you name a relatively recent extinction
and identify the cause(s)?
* NWF web site
Carolina
Parakeet
- 1918
→
http://en.wikipedia.org/wiki/Dodo
www.buffaloparrot.com/parrotfacts.htm
←
passenger
pigeon
“Martha”
- 1914
godwin.bobanna.com/rrr.html
dodo
↑
Mauritius -mid 17th century
←
thylacine
(Tasmanian
wolf)
- 1933
The Tragedy of the Commons
- a simulation of the complexities of resource management.
Resource management [renewable vs. non]
Fisheries will act as a
complex example,
because of the difficulty of
monitoring the seas.
Wealthy, well-equipped
nations tend to
deplete the resource
to unsustainable levels.
How do we measure the resource?
Who sets the limits?
Who monitors the take?
What are the penalties for cheating?
Tragedy of the commons
Chesapeake and Georges Banks
as examples.
Aquaculture as partial solution.
http://www.seafriends.org.nz/issues/fishing/fishcmap.gif
other resources to manage:
Land, soil, forests, water, air…
Also energy, fossil fuels, wildlife..
Why should
we care?
Do you remember talking about carbon footprint?
There is a parallel measure that looks at sustainability,
taking into account the management of diverse resources:
Ecological Footprint
Take a look at this website (consider the sources they cite):
www.footprintnetwork.org
Under ‘footprint basics’, go to ‘personal footprint’,
and after doing a survey,
it will tell you how many “Earths” would be required
to maintain all the people at your level of consumption.
This may
or may not
be homework
Conservation
- nature reserves cover a broad range of lands
from relatively pristine to actively managed.
- The size of the managed land plays a role:
bigger is likely to ensure more diversity,
but something is better than nothing…
Trail in Guana River
State nature preserve.
- wildlife corridors
allow animals to pass from one fragmented island
to another,
optimizing the benefits of limited reserve land.
← in Teton National park,
bridging summer and
winter grazing lands.
On a smaller scale,
fences and tunnels to
guide turtles away
from highways.
→
- active land management includes
www.stetson.edu/~pmay/stock%20habitat.htm
controlled burns
invasive species
removal
hunting/fishing
(sportsmen
often
are active in
conservation
efforts.)
limited lumbering
- restoration
reclaiming land that was altered,
and facilitating succession.
(This can be expensive, but reclaims the original area’s uses.)
ex. plans for the Everglades/Okeechobee
ex. Kissimmee River in south Florida↓
mitigation
Swapping replacement habitats for those lost to development.
If you have to fill a wetland in on place to build houses,
you build one someplace else to make up for it.
In Florida, the rules are numerous, arcane,
and sometimes logic-defying.
- Is a “new” wetland as diverse as an “old” one?
- What if the new wetland is far away?
← Longleaf Mitigation bank,
serving Baker, Duval and
Nassau counties….
www.longleafmitigation.com/servicearea.html
- in situ conservation
on site, in nature
includes aquatic preserves
-assorted no-take zones,
invasive-removal lands,
protected marshlands,
and open sea reserves
are recovering their marine
biodiversity.
in situ terrestrial conservation:
- wilderness areas (estab. 1964 in U.S.)
are land put aside to protect ecosystems:
-They are generally open for non-mechanized public access.
- The idea is to protect ecosystems, rather than isolated species
- Protecting land for future generations to experience.
One settler in the early 1600s
stated, "Wilderness is a dark and
dismal place where all manner of
wild beasts dash about
uncooked." *
* http://www.wilderness.net/index.cfm?fuse=NWPS
- ex situ conservation efforts
- allows more precise control
- generally a last measure.
captive breeding
programs
(White Oak
Conservation
Center)
ex situ conservation
US botanical garden, DC↑ botanical gardens
←Kew gardens, London are essentially zoos,
Phoenix, AZ√
but for plants
www.planetware.com/picture/london-kew-gardens...
seed banks are investments against
future loss of plant species
diversity and genetic diversity.
Svalbard, Norway
opened for business.
greenlineblog.com/svalbard-global-seed-vault/
What is meant by in situ versus ex situ?
Discuss the human population size
relative to the phases of the growth curve:
What might determine K?
Have you ever seen the Milky Way?
If so, when? Where?
Do you care if you haven’t,
and if you might never?
Global warming: Contrast with the greenhouse effect.
What effects of global warming are you aware of?
Research a recent extinction (<100 years).
What factors contributed to it?
What other resources might be worth protecting?
Why?
How?
Benchmark SC.912.L.17.20
Predict the impact of individuals
on environmental systems,
and examine how human lifestyles
affect sustainability.
Enduring Understandings
Ecosystems adapt
and change in
response to short term
changes on Earth
Essential Questions
How do the needs and
wants of humans affect
their surroundings?
agricultural revolution
ozone
industrial age
CFCs
age-structure diagram
Tragedy of the commons
demographics
aquaculture
biodiversity
nature reserve
genetic diversity
wildlife corridor
species diversity
active land management
richness
restoration
evenness
mitigation
ecosystem diversity
in situ conservation
alien species
wilderness area
biological control
ex situ conservation
biomagnification
captive breeding
DDT
botanical garden
mercury
seed bank
extinction
.
biodiversity
invasive species
native species
global warming
sustainable development