Quiz 3 Study Guide Flashcards
Biodiversity: What is it?
the variety of living organisms considered at all levels of organization, including the genetic, species, and higher taxonomic levels, and the variety of habitats and ecosystems, as well as the processes occurring therein.
What is the Biosphere?
Biological diversity Ecological and evolutionary processes Genes Species Habitats Communities
Ecosystems Nutrient cycling Water cycling Photosynthesis Predation Mutualism Speciation
Species
A distinct type of organism, a set of individuals that uniquely share certain characteristics and can breed with one another and produce fertile offspring
Endemic species
Native or restricted to a particular geographic region. An endemic species occurs in one region and no where else on Earth.
What is happening to biodiversity?
We are losing our biodiversity at around 100-1000x background rate. Educated guess we will lose between 5-40% by 2100. Losing between 20-75 species a day.
What are the causes of current extinctions?
Habitat loss/fragmentation Human harvest/exploitation Invasive species (transported by humans) Pollution (nitrogen, phosphorus) Over exploitation Global climate change (don't know the effect, but it's likely to be big)
What three types of values of biodiversity to humans?
Direct
Ecological Services
Intangible
What does Direct value of biodiversity mean?
A lot of species that we directly use.
Everything we eat is a species. Corn, rice, avocado, meat, etc.
everything for shelter, clothing, etc. wood, cotton, etc.
Most medicines are derived from plant compounds. Discovered and undiscovered.
What does Ecological Services value of biodiversity mean?
Ecological Services
Ecosystem services on earth are worth approx $33 trillion per year
What does Intangible value of biodiversity mean?
Educational value
Scientific value
Aesthetic
Recreational (fishing, hunting, etc.)
What are the ethical values of biodiversity and intrinsic value?
Species has a right to exist outside the value it is utilitarian to humans
e.g. Polar bears. No specific value to the human species, but we still feel they have a right to exist. Toxic pollution and climate change are two things killing off polar bears, our fault for their endangerment. Intrinsic value to every living thing to not allow them to go extinct.
What is Endangered Species Act of 1973?
Endangered Species Act created a protocol to decide which species are endangered and protocol to protect them. States what you can and cannot do.
Valuation of non-market environmental goods, How can we know?
One approach to finding out how much an ecosystem service is worth is by
conducting a survey. Or we could calculate how much it would cost for us to reproduce the service.
Willingness to pay versus Willingness to sell
To a market economist, this is a way to evaluate the popular value of part of our ecosystem and they should turn out equal. However, they usually do not turn out equal and instead are disproportionate with the amount to pay being much lower than the amount to sell.
What is the current global distribution of forests?
Forests currently cover 31% of the Earth’s land surface.
Trends: what is happening to forests in MDC’s
MDC (most developed country)
Timber harvest
Sprawl
Agriculture
Trends: what is happening to forests in LDC’s
LDC (least developed country) - driven by necessity, need for foreign currency, economic disparities
Land clearing for agriculture and settlement
Firewood collection
Timber harvest
Old-growth (primary) vs. second growth (secondary)
By the 20th century, very little primary forest - natural forest uncut by people - remained in the lower 48 US states and today even less is left. Nearly all the large oaks and maples found in eastern North America today, and even most redwoods of the California coast, are merely second-growth trees: trees that sprouted after old-growth timber was cut. Such second growth trees characterize secondary forest.
What are values of forests in economic terms?
Most economic benefits are short term, reaped not by local residents but by the foreign corporation. Local people may receive temporary employment, but once the timber is gone they no longer have the forest and the ecosystem services it had provided. Moreover, much of the wood extracted in developing nations is exported to Europe and North America. In this way, our consumption of high-end furniture and other wood products in developed nations can fuel forest destruction in poorer nations.
History of forest in U.S. over the last 400 years
As the US and Canada expanded westward across North America over the past 400 years, forests were cleared for timber and farmland. The vast deciduous forests of the East were cleared by the mid-19th century, making way for countless small farms. Timber from these forests built the cities of the Atlantic seaboard and the upper Midwest. As a farming economy shifted to an industrial one, wood was used to stoke the furnaces of industry. Logging operations moved south, where vast pine woodlands and bottomland hardwood forests were cleared and replaced with pine plantations. Once mature trees were removed from these areas, timber companies moved west, cutting the continent’s biggest trees in the Rocky Mountains, the Sierra Nevada, the Cascade Mountains, and the Pacific Coast ranges. Exploiting forest resources helped American society to develop, but we were not harvesting forests sustainably.
Why do we have National forests?
We began managing forest resources in the US a century ago in response to rampant deforestations and widespread fear of a timber famine. This led the federal government to form a system of forest reserves: public lands set aside to to grow trees, produce timber, protect water quality, and serve as insurance against scarcities of lumber. US National Forest system is 191 million acres / 8% of nations land.
What did the 1976 National Forest Management Act do?
Mandated that every national forest draw up plans for renewable resource management, subject to public input under NEPA. Guidelines specified that these plans assess the ecological impacts of logging. As a result, timber harvesting methods were integrated with ecosystem based management goals, and the USFS developed programs to manage wildlife and restore degraded ecosystems.
Comparing and contrasting Maximum Sustained Yield and Ecosystem Management
MSY is maximizing timber harvest while Ecosystem management is more about managing the whole forest
Managing for socially optimal production - trying not to be wasteful, deal with externalities by internalization
What is Maximum Sustained Yield (or MSY)?
To achieve the maximum amount of resource extraction without depleting the resource from one harvest to the next. Recall the logistic growth curve, which shows how a population grows most quickly at an intermediate size - specifically at one half carrying capacity.
What is Clear-cutting as a method of harvest?
Most timber has been harvested by clear cutting in which all trees in an area are cut at once. Clear cutting is cost efficient and to some extent it can mimic natural disturbance events such as fires, tornadoes, or windstorms.
There are ways to harvest forests that are not clear cutting:
Seed tree or shelter system
Selection system
What is Ecosystem based management?
Aims to minimize impact on the ecological processes that provide the resource. Many certified sustainable forestry plans protect certain forested areas, restore ecologically important habitats, and consider patterns at the landscape level, allowing timber harvesting while preserving the ecological processes and functional integrity of the forest ecosystem.
They are called externalities because the logging company (the producer) does not assume these costs. What kinds of externalities are the logging companies not assuming?
Erosion - Causes silt in streams which hurts water quality, pollution, and fish losses (like salmon who cannot reproduce in silty water)
Habitat loss / species loss
Nutrient depletion
Not as much carbon gets stored
Loss of intangible values
Specialists species or species that are most endangered are from old growth forests. Clear cut forests have higher diversity, but only because they are harboring plentiful species.
What are some of the impacts of current conventional forest management using monoculture, crop style?
North America’s timber industry focuses on production from plantations of fast-growing tree species planted in single species monocultures. Because all trees in a given stand are planted at the same time, the stands are even-aged, with all trees the same age. Stands are cut after a certain number of years (called the rotation time), and the land is replanted with seedlings. Plantation forestry is growing worldwide, and today fully 7% of the world’s forests are plantations. One quarter of these feature non-native species. When a plantation replaces a natural forest, the community undergoes simplification. Indeed, ecologists and foresters view plantations more as a crop agriculture than as ecologically functional forests. Because there are few tree species and little variation in tree age, plantations do not offer many forest organisms the habitat they need. Plantations lack the structural complexity that characterizes a natural forest. Plantations are also vulnerable to outbreaks of pest species.
Sustainable (green) forestry certification - (I.e. Forest Stewardship Council)
Affords the ability to sell wood for a higher price which allows higher profitability because the logging company has internalized the externalities of traditional logging
Green certification for wood has not taken off like organic food. Likely to fail because perception of value, missing the personal perception of health connection.
Land set-asides - “land trusts” A private organization, generally local or regional, that preserves lands valued by its members. In most cases, land trusts purchase land outright with the aim of preserving it in its natural condition.
Deforestation in the tropics recent and current trends
Tropical deforestation accounted for more than 32% of total global forest loss, nearly half of which occurred in South American tropical rainforests.
Deforestation of tropical dry forests of South America had the highest rate of tropical forest loss, due to deforestation dynamics in the Chaco woodlands of Argentina, Paraguay, and Bolivia - NOT in BRAZIL! - mostly related to agrobusinesses.
What some impacts of tropical deforestation?
Tropical deforestation occurs in tropical latitudes Linked to environmental change at a global scale Debate centers around the rate of forest cover change and the causes of this change Single factor causation (shifting cultivation, population growth, agriculture expansion) Irreducible complexity (multiple cultivation, population growth, agricultural expansion) factors that interact with each other in such a complex way that no traceable pattern emerges)
Direct uses / services from forests
Food Timber Photosynthesis / oxygen Paper Medicines Nutrient cycling Water cycling Climate moderation Hazard mitigations (Mangrove forests) Carbon storage (I.e. Climate change)
