Sustaining Biodiversity
2012
Priorities for Protecting Biodiversity
• Map terrestrial and aquatic biodiversity
• Immediately preserve biodiversity hotspots
• Keep old-growth forests intact
• Protect and restore lakes and rivers
• Initiate ecological restoration
• Make conservation profitable
34 Global Hotspots
Biodiversity Hotspots in the U.S.
North American Gray Wolf
• Reduced to a few
hundred
• Keystone species
• Restoration proposal
angered ranchers,
hunters, loggers
• 1995, reintroduced in
Yellowstone, 136 by 2007
• Positive ripple effect after
reintroduction
How Should We Manage and
Sustain Forests?
• We can sustain forests by
– recognizing the economic value of their ecological
services
– protecting old-growth forests
– harvesting trees no faster than they are
replenished
– making most paper from fast-growing plants and
agricultural residues instead of trees.
Old-growth
Forest
Short Rotation Cycle Forestry
Loss of Original Forests
• 46% in 8,000 years, most since 1950
• Most in tropical areas, developing countries
• Estimated loss of 40% intact forests within
next 20 years
Return of Forests in the United States
• Second- and third-growth forests fairly diverse
• More wood grown than cut
• 40% of forests in National Forest System
• Forests transformed into tree plantations
Forest Harvesting Methods
Clear-cut Logging
Management of Forest Fires
• Fire suppression in all types of forests
• Some forests naturally fire adapted
– NJ Pine Barrens need fire to open cones
• Restoration of fire’s natural role
– NJ Great Swamp needs fire to maintain habitat for
migratory birds
Trees and Paper
• Many trees are cut for paper production
• Alternatives
– Pulp from rice straw and agricultural residues
(China)
– Kenaf (U.S.)
Solutions: Kenaf
In California, Texas and Louisiana, 3,200
acres of kenaf were grown in 1992, most
of which was used for animal bedding
and feed
Kenaf grows quickly, rising to heights of
12-14 feet in as little as 4 to 5 months.
U.S. Department of Agriculture studies
show that kenaf yields of 6 to 10 tons of
dry fiber per acre per year are generally 3
to 5 times greater than the yield for
Southern pine trees, which can take from
7 to 40 years to reach harvestable size.
How Serious Is Tropical Deforestation and How Can It
Be Reduced?
• We can reduce tropical deforestation by
protecting large forest areas
• teaching settlers about sustainable agriculture
and forestry
• using government subsidies that encourage
sustainable forest use
• reducing poverty
• slowing population growth
http://nksandeep.files.wordpress.com/2009/03/deforestation-in-the-amazon.jpg
Tropical Forests
•
•
•
•
Cover 6% of earth’s land area
Habitat for 50% of terrestrial plants and animals
Vulnerable to extinction – specialized niches
Rapid loss of 50,000–170,000 km2 per year
How to Protect Tropical Forests
• Teach settlers to practice small-scale
sustainable agriculture
• Harvest renewable resources from the forests
• Debt-for-nature swaps
• Conservation concessions
• Better logging methods
Miners rely heavily on
hydraulic mining techniques,
blasting away at river banks
with high-powered water
cannons and clearing forests
to expose potential goldyielding gravel deposits.
GOLD MINING &
consequences
Gold is usually extracted
from this gravel using a
sluice box to separate
heavier sediment and
mercury used to
amalgamate the precious
metal.
“Mercury sales are poorly regulated and its use is
widespread…bioaccumulation of mercury in fish poses health
threats to people living downstream.
Fish account for the major share of protein in the diet of local
residents, …Venezuela's Minister of Environment, said that it
will take 300 years to re-plant destroyed forest in the area and
70 years to decontaminate areas polluted by the miners.”
http://news.mongabay.com/2006/1109-atbc.html
Reducing Native Biodiversity
by Species Introductions
• Most beneficial – food crops, livestock, pest
control
• 500,000 alien invader species globally
• 50,000 nonnative species in the U.S.
• The economic toll from damage by invasive
species—and the costs of trying to control
them—is enormous: U.S. $137 billion a year,
according to a 1999 Cornell University study.
Deliberately Introduced Species
Accidentally Introduced Species
Case Study: The Kudzu Vine
• Kudzu introduced to control erosion
• Prolific growth
• Uses
– Asians use powdered starch in beverages
– Source of tree-free paper
– Japanese kudzu farm in Alabama
Invasive Kudzu Vine
Disruptions from Accidentally
Introduced Species
• Downside of global trade
• Argentina fire ant
• Burmese python
13-foot (4-meter) Burmese
python in Florida's Everglades
National Park, the headless
python was found in October
2005 after it apparently tried to
digest a 6-foot-long (2-meterlong) American alligator
http://news.nationalgeographic.com/
Human Impacts on Aquatic Ecosystems
• Destroyed or degraded by human activities
• Ocean floor degradation 150 times larger than area clear-cut
annually
• 75% of most valuable fish species overfished
• Likely extinction
– 34% marine fish species
– 71% freshwater species
Effects of Bottom Trawling
Fig. 8-25, p. 172
Why Is Protection of Marine
Biodiversity So Difficult?
• Human aquatic ecological footprint expanding
• Not visible to most people
• Viewed as an inexhaustible resource
• Most ocean areas outside jurisdiction of a
country
What Should Be Our Priorities for
Protecting Biodiversity?
• Sustaining the world’s biodiversity requires
– mapping terrestrial and aquatic biodiversity
– protecting terrestrial and aquatic hotspots
and old-growth forests
– initiating ecological restoration projects
worldwide
– making conservation profitable.