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Biodiversity and Land Use. Saving Species from Us. I. Dilemmas of Land Use Policy. Types of land use in the United States Urban Small proportion of land (about 3%) but growing rapidly due to urban/suburban sprawl Most of US population housed in urban areas (about five-sixths)
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Biodiversity and Land Use Saving Species from Us
I. Dilemmas of Land Use Policy • Types of land use in the United States • Urban • Small proportion of land (about 3%) but growing rapidly due to urban/suburban sprawl • Most of US population housed in urban areas (about five-sixths) • Key policies = urban growth initiatives limit growth into surrounding low-density land (and thereby increase property values and exclude low-income residents)
2. Agriculture • 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 • 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 • Importance: Natural pollution filters, flood control, replenishment of aquifers, biodiversity • Threats: Expansion of agriculture accounts for most wetlands loss since 1950 • Rate of loss has slowed since 1970s • Key policies = Clean Water Act, “no net loss” rule
b. Deserts • 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) • 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 • 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.
6. Sea: The Outer Continental Shelf • 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 • 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 • Definition: Number of distinct species in an area (not necessarily number of individual plants or animals) • Why do we care? • Species extinction = irreversible loss of unique genetic codes that may lead to development of medicines, foods, and jobs • Genetic diversity useful for agriculture – creates pool of potential hybrids, esp. when new plant diseases strike (example: banana)
C. Is Biodiversity Decreasing? • 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)
D. Strategies to conserve biodiversity • 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 • 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 goose-bumps, 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 • Concept: Remove the keystone species and other species will follow. • 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.
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 • Home on the range? Public grasslands policy and ranching in Western states • The problem: Grazing animals are selective, removing preferred species and leaving non-preferred species to survive and reproduce (leads to desiccation and desertification)
2. The context • 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 • 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 • Fees charged for grazing on public lands are far below market value and represent an enormous “hidden subsidy” to western ranchers. • 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 • 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 • Logging “Old Growth” in the Pacific Northwest • Value of ancient forests • Temperate rainforests are second only to tropical rainforests in terrestrial biodiversity. • 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 • Less than 10% of virgin temperate rainforest remain worldwide (80% scheduled to be cut in the near future)
c. Economic Interests • 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 old-growth forests where endangered spotted owls were found. Timber industry claims 40,000 jobs lost, while environmentalists dispute number.
2. Politics of the USFS • 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.