Transcript Biodiversity and Land Use

Biodiversity and Land
Use
Saving Species from Us
I. Dilemmas of Land Use Policy
A.
Types of land use in the United States
1. Urban
a. Small proportion of land (about 3%) but growing
rapidly due to urban/suburban sprawl
b. Most of US population housed in urban areas
(about five-sixths)
c. Key policies = urban growth initiatives  limit
growth into surrounding low-density land (and
thereby increase property values and exclude
low-income residents)
2. Agriculture
a.
b.
c.
d.
Largest single land use: 36% of US land 
more than 50% if grazed woodlands and rural
ponds, roads, and homesteads are included
(and more than 60% of lower 48)
Divided about evenly between cropland and
pasture (rangeland), with smaller amounts of
grazed woodland
Effects: Pesticide and fertilizer runoff, water
use, loss of biodiversity
Key policies: regulation of pesticides,
incentives to leave land fallow, water subsidies
3. Forests
a.
b.
c.
About one fourth of the US
Relatively high biodiversity, very low
population density
Key policies: Timber, mining, road
construction, fire control
4. Wilderness: About 20% of US
(only 10% of lower 48)
Wetlands
a.
i.
Importance: Natural pollution filters, flood
control, replenishment of aquifers,
biodiversity
ii. Threats: Expansion of agriculture accounts
for most wetlands loss since 1950
iii. Rate of loss has slowed since 1970s
iv. Key policies = Clean Water Act, “no net
loss” rule
b. Deserts
i.
ii.
iii.
Moderate biodiversity – lower than forests or
wetlands but greater than tundra
Threat: Damage is easiest to marginal
ecosystems. Examples = walking or driving
that disturbs biotic desert crust  invasive
grasses, loss of nitrogen-fixing bacteria, loss of
biodiversity
Key policy = protected status of individual
deserts (little damage can be absorbed 
multiple-use difficult to reconcile with
environmental protection)
c. Tundra (Alaska)
i.
ii.
iii.
Low biodiversity on land  extremely
fragile
Threats: Energy exploitation (drilling,
roads, oil spills, pollution)
Key policies: Status of ANWR (see
textbook), National Petroleum Reserve
(est. 1957), tanker/export regulations on
Alaskan crude oil
5. Protection Status
a.
b.
c.
d.
Bureau of Land Management (BLM) – very friendly
to mining and ranching interests  multiple use.
Forest Service (USFS) -- less friendly to business
interests than BLM  multiple use modified by
sustainable yield, conservation
Fish & Wildlife Service: political football due to role
in Endangered Species Act (ESA)  conflict
between scientists and managers. Lands are
moderately-restricted use (Dept. of Interior
permission required for exploitation)
National Park Service: most land protected from
development, major threat is tourism. Restricted
use.
Locations of Parks, Preserves,
Forests and Refuges
6. Sea: The Outer Continental Shelf
a.
b.
c.
Key dilemma = energy (risk of spills) and
sewage vs. biodiversity
Other dilemma = fisheries vs.
biodiversity (over-harvesting)
Key policy = Outer Continental Shelf
Lands Act
B. Property Rights and Policies
1.
2.
3.
4.
Multiple Use vs. Preservation: Multiple uses
conflict with each other, reducing
environmental protection
Federal vs. State: States desire control, not
necessarily development (but states with
powerful ranching, mining, agriculture interests
will probably use the land for those interests)
Private vs. Public: Confused by varying degrees
of “privateness” – i.e. Forest Service building
roads for private harvesting of timber
Regulation and Rights: The Wise Use
Movement (more later in the environmental
law unit)
C. Input Trade-Offs

Limit land  more intensive use of other
resources  more damage to environment
– Example: Limit farmland = incentives to use
fertilizers, grow strains of maximal efficiency
(leading to monoculture), cultivate land more
instensively
II. Biodiversity
A.
B.
Definition: Number of distinct species in
an area (not necessarily number of
individual plants or animals)
Why do we care?
1. Species extinction = irreversible loss of
unique genetic codes that may lead to
development of medicines, foods, and jobs
2. Genetic diversity useful for agriculture –
creates pool of potential hybrids, esp. when
new plant diseases strike (example: banana)
C. Is
Biodiversity
Decreasing?
1.
2.
3.
Speciation is slow –
Evolution works on
long time scales
Species extinction is
occurring – implies
that biodiversity is
decreasing, since
speciation is so slow
Rate of decrease is
disputed
a. Definitions affect conclusions
(shift to 50-year standard in 1990s
decreases extinctions until 2040s)
b. Most studies show increasing
extinction rate
c. Known Species Extinctions
d. Species at Risk
D. Strategies to conserve
biodiversity
1.
Habitat protection – usual cause of
extinction is not direct killing but loss of
habitat
SPECIES-AREA RELATIONSHIP
Diminishing returns to area  Important issue for
conservation: the loss of biodiversity occurs at an increasing
rate as area gets smaller
D. Strategies to conserve
biodiversity
1.
2.
Habitat protection – usual cause of
extinction is not direct killing but loss of
habitat
Identifying critical species – different
strategies compete for policy
implementation
a. Flagship Species
•Species that are selected to attract attention and
funding from the public for conservation projects.
•“ …animals that are huge, ferocious, cuddly, cute, or of
direct benefit to humans; they are the charismatic
animals most likely to make people smile, feel goosebumps, and write a check for conservation.” (Mills)
•Flagship species might not be good surrogates for
broader biodiversity or ecosystem protection.
•What happens if the flagship sinks? Will public
emotional investment in species turn to disenchantment
with conservation in general? (Simberloff)
Charismatic Flagship Species
(Mills)
b. Umbrella Species
•Species whose conservation provides protections for many co-occurring
species.
•Traditionally, umbrella species have had large area requirements (large
animals and carnivores).
•Idea is that if we conserve enough habitat for the umbrella species, then
other species should be covered as well. Concept has been applied to
selecting nature reserves.
•Little scientific evidence  policy appears to be “precautionary principle”
applied to species BUT some evidence indicates that range sufficient for
large animals can actually be too small for many other animals
c. Indicator Species
• “…Organism whose
characteristics (presence or
absence, population density,
dispersion, reproductive success)
are used as an index of attributes
too difficult, inconvenient, or
expensive to measure for other
species or environmental
conditions of interest.”
•Analogy: Canary in the coal mine
•Typical examples: amphibians,
fish (both are highly sensitive to
pollution)
d. Keystone Species
i. Concept: Remove the keystone species and other species will
follow.
ii. Criteria: species whose impact on ecosystem is large and
disproportionately large relative to its abundance or biomass.
iii. Examples

Sea Otter:
iii. Examples

Sea Otter: Otters eat urchins.
iii. Examples

Sea Otter: Otters eat urchins. Urchins eat
kelp.
iii. Examples

Sea Otter: Otters eat urchins. Urchins eat
kelp. When otters decline, the urchin
population explodes and eats all the kelp.
iii. Examples

Sea Otter: Otters eat urchins. Urchins eat
kelp. When otters decline, the urchin
population explodes and eats all the kelp.
Many species use the kelp forest for cover;
absence of kelp is similar to
transformation from forest to desert
ecosystem.
Kelp
Forests 
Urchin
Barrens
iii. Examples

Sea Otter: Otters eat urchins. Urchins eat
kelp. When otters decline, the urchin
population explodes and eats all the kelp.
Many species use the kelp forest for cover;
absence of kelp is similar to
transformation from forest to desert
ecosystem.
– Bonus: Sea Otters are food for Orcas (but this
means too many Orcas too close to shore can
be a problem…)
Another example: Starfish
Starfish eat the most competitive mussels, creating
niches for less competitive ones (and thus higher
biodiversity on rocky shores)
III. Policy Dilemmas
A.
Home on the range? Public grasslands
policy and ranching in Western states
1. The problem: Grazing animals are selective,
removing preferred species and leaving nonpreferred species to survive and reproduce
(leads to desiccation and desertification)
2. The context
a.
b.
c.
d.
About 60% of US rangeland is privately owned (usually
managed sustainably for maximum profit, but with low
biodiversity). Most productive rangeland is actually in
the East (i.e. where it rains and food grows)
A few ranchers control most federal range (2% of
livestock producers have allotments and 98% don’t).
5% of allotment holders control 58% of the herbiage.
Vast areas required due to low food density: 90% of
BLM land is used for grazing BUT only 2% of cattle
and 10% of sheep graze on public land.
Confusion of public and private lands due to “base
area” requirements and management terms of permits.
Arizona example: Average ranch has 7 public acres for
each acre of privately-owned land. (Is this really the
rancher’s ranch?)
3. State of the Range
a.
b.
Status: Natural Resource Defense
Council claims 30% of public rangelands
are in fair condition, while 55% are in
poor or very poor condition.
Some groups regard cattle grazing as the
most ubiquitous form of ecosystem
degradation in the southwestern U.S.
Many call for a complete grazing ban on
all public lands.
4. Grazing Fees
a.
Fees charged for grazing on public lands are
far below market value and represent an
enormous “hidden subsidy” to western
ranchers.
–
–
–
b.
1999 minimum charge was $1.35 per cow per
month.
Comparable private land fees were $11.10 per cow
per month.
Estimates are that administrative costs alone are
$3.21 per animal unit, i.e. the public loses money
on the deal!
Half of fees are returned to fund for ranch
development
5. Solutions
a.
b.
c.
d.
Charge market rates – Most ranchers would
probably pay the higher fees, since total costs
dwarf fees anyway. Result = more money, but
no change in ecology or biodiversity
Competitive bidding – Market is limited since a
few ranchers control most adjacent land 
little incentive for distant ranchers to bid high
Ban ranching on public lands – Would increase
beef/lamb prices by a few percent and
generate local unemployment in rural areas,
but would increase biodiversity and possibly
save money over status quo.
Other ideas? Land transfer or privatization,
shift land from BLM to other agencies, etc.
B. Forest Management
1.
Logging “Old Growth” in the Pacific
Northwest
a. Value of ancient forests
i.
Temperate rainforests are second only to tropical
rainforests in terrestrial biodiversity.
ii. Accumulate more biomass in standing vegetation per
unit area than any other ecosystem on earth.
Example: Redwoods can reach 3-4 m in diameter, 90
m in height and 1,000 years in age
b. Less than 10% of virgin temperate rainforest
remain worldwide (80% scheduled to be cut in
the near future)
c. Economic Interests
i.
ii.
Forest products industry: Employs about
150,000 people in the Pacific NW, and adds
nearly $7 billion annually to the economy.
Impact of regulation: In 1989, USFS sued
over plans to clear-cut remaining oldgrowth forests where endangered spotted
owls were found.  Timber industry claims
40,000 jobs lost, while environmentalists
dispute number.
2. Politics of the USFS
a.
b.
Goal: USFS has historically regarded its
primary job as providing a steady supply
of cheap logs to the nation’s timber
industry.
Pricing: Timber prices are often too low
to repay management costs (hidden
subsidy to timber industry -- USFS builds
roads in order for timber companies to
extract trees)
3. Fire Management
a. Fire suppression: For more than 70 years,
firefighting has been a high priority for
forest managers.
b. Fire suppression failed
Suppression allows build-up of twigs and
other dead matter. In dry climates, we
call this stuff “tinder” and it makes fires
inevitable – and very, very hot.
 Example: Southern California. “Burns on a
regular basis” should probably be in the
sales brochures.

c. Ecological consequences of
suppression
i.
ii.
iii.
Eliminating fire has allowed shrubs and
small trees to fill some forest floors,
crowding out grasses and ferns (changes
composition of forests)
Hotter fires become “crown fires” that
leap from treetop to treetop, killing
normally fire-resistant species
Examples of areas that “need” regular
fire to germinate seeds, etc:
Southern Pine Communities
Fire prepares the soil
for the seeds of
Southern pine by
removing litter and
releasing soil
nutrients
 Removes other
competitive species.

Jack Pine Communities of the Great
Lakes Region

Jack Pine has
Serotinous cones
which need fire to
release seeds
Benefits of fire in Alaska's Boreal
Forest and Tundra
Fire returns nutrients
to the soil by breaking
down dead materials.
 This leads to a rapid
proliferation of
growth, benefiting
both plants and
animals.

d. Approaches to Fire Management
i.
ii.
iii.
iv.
Status quo = allow small, natural fires to
burn until they threaten property or lives
“Fire ecologists” favor small, prescribed
burns and limits on human encroachment
on forests
Logging industry advocates encourage
“salvage logging” -- removal of dead or
dying trees from fire-damaged forests
Selective deforestation is advocated by
some home-builders and insurers (remove
trees from 60-yard radius around houses)
4. Types of Forest Management
a. Even-aged management
– forest is cut down, and regrowth trees are
maintained at the same size and age
– monoculture
– industrial forestry
– high industrial productivity / low biodiversity
b. Uneven-aged management
variety of tree species are maintained at
different sizes and ages
 fosters natural regeneration
 high diversity
 long term production of high quality
timber


Strategy decision is based upon return
timetable of money required
c. Harvest Methods
i. Clear-Cutting - Every tree in a given area is
cut regardless of size.
– Fast and efficient, but wastes small trees,
increases erosion, and eliminates wildlife habitat.
 Early-successional species flourish.
– Variant = strip cutting, which cuts small strips
each year to allow forest to re-seed itself.
Somewhat less destructive but requires much
larger areas of forest
ii. Selective Cutting

A small percentage of
mature trees are taken in
10-20 year rotation.
– Can retain many
characteristics of mature, oldgrowth forests.

Industry says it is
unprofitable;
environmentalists worry
other trees will be damaged
by cutting selective ones
C. Mountaintop Removal Mining
1. Description: Remove the top of a mountain to get
at the coal seam. Dump the removed material in
neighboring streams and valleys.
2. The
controversy
a.
b.
Environmental
impact – filling
valleys with
mining waste is
bad for things
that live there
Health impact –
destruction of
clean water
supplies with
toxic slurry
c. Flooding
Destruction of valleys
diverts more water to
remaining ones (towns
are located in the
valleys)
Bob White, WV

7 floods since
mountain-top mining
begun in 2000
3. Economic Interests
a.
b.
c.
Mountaintop removal is cheaper than
other methods for coal seams in
mountains
Coal is important (over half of US
electricity production)
Only 5% of coal is produced using this
technique, but in a few states it is more
(30% in WV)  concentrated interests in
WV, KY, and possibly TN and VA (by
2010)
4. The Status Quo
a.
b.
c.
d.
Key law = Surface Mining Control and
Reclamation Act (1977)
Law requires restoration of mining areas to
pre-mine condition but allows waivers (Section
515-c-1) for mountaintop removal
Lobbyists for coal industry have successfully
blocked most funds for enforcement anyway
Also important = Clean Water Act. Bush
Administration reinterpreted mining waste as
inert “fill” rather than a pollutant, allowing
dumping into valleys  dramatic increase in
use of technique, plans to expand to other
states
IV. Proposals for Protecting Habitat:
Biosphere Reserves
A.
Division of reserves
1. Core area - no disturbance
2. Buffer zone - managed activities
3. Transition zone - sustainable forestry and
conservation
B. Selection Strategies
Select two areas for reserves. Which strategy should you use?
A
B
C
D
1
2
3
4
1
2
3
4
1
2
5
3
4
6
Hotspots: A & B have highest levels of biodiversity
Greedy Algorithm: either A or B, then either C or D
Optimal solution: C & D (protects all species)
Highlights the importance of “complementarity”
C. Site vs. Budget Constrained
Approach
Site constrained approach: for a given
number of sites, choose the combination
that covers the maximum number of
species (just use species data, ignore
cost)
 Budget constrained approach: for a given
budget, choose the combination of sites
that is affordable and covers the maximum
number of species

D. Application to the US
1. Data:
– Endangered species by county (US EPA)
– Average per acre value of agricultural land
(USDA)
2. Cost-minimizing strategies are usually
more efficient in the US, especially if funds
are quite limited
E. Conservation in Working Landscapes:
Beyond Reserve Site Selection
1. What about the 90% of land outside of
protected areas?
– Many biodiversity elements can tolerate at least some
level of human disturbance and alteration of the
landscape
– Does the entire landscape, including both protected
areas and working areas outside of protected areas,
provide a sufficient likelihood that elements of
biodiversity will be sustained?
2. Consequences of land use
decisions
a. Optimal land use: As a function of land
use decisions, Polasky et al (2005) track
– Species persistence for set of 97 terrestrial
vertebrates (Landscape biological score: LB)
– Value of commodity production for timber,
agriculture (Landscape economic score: LE)
Trade-offs and the “efficiency
frontier” determine optimal use
LB (# of Species)
90
85
Efficiency Frontier
Figure 3e
Figure 3d
Figure 3c
Figure 3b
Figure 3a
80
75
70
0
250
500
750
LE (Millions of Dollars)
1,000
b. Optimal/Efficient Land Use
versus Actual Land Use
Actual patterns of land use and land
management are quite different than what
is shown as optimal by any of these
studies. Why?
 Externalities problems

– Failure to be rewarded for providing public
goods (biodiversity)
– Failure to be punished for causing harm to
others (loss of biodiversity, pollution, etc.)
VI. Conclusions
Each area of land has its own environmental
dilemmas caused by distinct economic interest
groups
 Typical dilemma pits moderate damage to
concentrated economic interests (the few)
against large damage spread across multiple
economic interests (the many)
 Dilemmas also involve growth-environment
trade-offs BUT these are often trivial compared
to the high salience/small numbers vs. low
salience/large numbers trade-off
 Far more consensus on problems than on
solutions, which remain under-studied
