APES Day 72!APES Day 72!

Respond to the quote by Adam Smith from The Respond to the quote by Adam Smith from The Wealth of Nations, “No society can surely be Wealth of Nations, “No society can surely be

flourishing and happy, of which the far greater flourishing and happy, of which the far greater part of the members are poor and miserable.”part of the members are poor and miserable.”

Please have your notes out…what are the main Please have your notes out…what are the main causes of desertification? Biomes affected?causes of desertification? Biomes affected?

Overgrazing and Land Overgrazing and Land DegradationDegradation

About one-third of the world’s About one-third of the world’s rangeland is severely degraded by rangeland is severely degraded by over-grazing.over-grazing.– Grazing animals usually exhibit selective Grazing animals usually exhibit selective

grazing, removing preferred species and grazing, removing preferred species and leaving non-preferred species to survive leaving non-preferred species to survive and reproduce.and reproduce.

Gradually, nutritional value of forage declines.Gradually, nutritional value of forage declines.– Denudation of ground leads to desiccation and Denudation of ground leads to desiccation and

desertification.desertification.

Forage Conversion by Domestic Forage Conversion by Domestic AnimalsAnimals

Ruminants are efficient at turning plant Ruminants are efficient at turning plant material into protein because bacterial material into protein because bacterial digestion in their multiple stomachs digestion in their multiple stomachs allows utilization of cellulose and other allows utilization of cellulose and other complex carbohydrates.complex carbohydrates.– Worldwide, 85% of ruminant forage comes Worldwide, 85% of ruminant forage comes

from native rangelands and pasture.from native rangelands and pasture.– In US only 15% of livestock feed comes In US only 15% of livestock feed comes

from native grasslands. 90% of our total from native grasslands. 90% of our total grain crop is used for livestock feed.grain crop is used for livestock feed.

Rangelands in the United StatesRangelands in the United StatesUS has approximately 319 million ha of US has approximately 319 million ha of rangeland.rangeland.– Most in the WestMost in the West

About 60% is privately owned.About 60% is privately owned.Only 2% of cattle and 10% of sheep graze on Only 2% of cattle and 10% of sheep graze on public land.public land.

– BLM manages more land than any other agency in BLM manages more land than any other agency in the US.the US.

Strong agency inclination towards resource Strong agency inclination towards resource utilization.utilization.

Grazing FeesGrazing Fees

Fees charged for grazing on public Fees charged for grazing on public lands are far below market value and lands are far below market value and represent an enormous hidden subsidy represent an enormous hidden subsidy to western ranchers.to western ranchers.– 1999 minimum charge was $1.35 per cow 1999 minimum charge was $1.35 per cow

per month.per month.Comparable private land fees were $11.10 per Comparable private land fees were $11.10 per cow per month.cow per month.

– Estimates are that administrative costs alone are Estimates are that administrative costs alone are $3.21 per animal unit.$3.21 per animal unit.

How do we manage forests?How do we manage forests?

Swidden AgricultureSwidden Agriculture

Can be ecologically sound and Can be ecologically sound and sustainable if performed carefully and sustainable if performed carefully and in moderation.in moderation.

Slash and BurnSlash and Burn– Hectare plot cleared, dried, and burned.Hectare plot cleared, dried, and burned.

Ashes used to prepare seedbed.Ashes used to prepare seedbed.– Fast-growing crops planted to control erosion, shade Fast-growing crops planted to control erosion, shade

crops, and anchor soil.crops, and anchor soil.

Cropped intensively for 1-2 years, and then rested Cropped intensively for 1-2 years, and then rested 10-15 years.10-15 years.

Logging and Land InvasionsLogging and Land Invasions

Other major source of forest Other major source of forest destruction is logging and subsequent destruction is logging and subsequent invasion.invasion.– Bulldozed roads make it possible for large Bulldozed roads make it possible for large

numbers of immigrants to move into the numbers of immigrants to move into the forest in search of farmland.forest in search of farmland.

Forest clearing leads to river degradation Forest clearing leads to river degradation through increased silt and sediment flow.through increased silt and sediment flow.

Forests are removed and replaced Forests are removed and replaced by pasture land…Mickey D’s!by pasture land…Mickey D’s!

Harvest MethodsHarvest Methods

Clear-CuttingClear-Cutting - Every tree in a given - Every tree in a given area is cut regardless of size.area is cut regardless of size.– Fast and efficient, but wastes small trees, Fast and efficient, but wastes small trees,

increases erosion, and eliminates wildlife increases erosion, and eliminates wildlife habitat.habitat.

Early-successional species flourish.Early-successional species flourish.

– CoppicingCoppicing - Encourage stump-sprouts. - Encourage stump-sprouts.– Seed-TreeSeed-Tree - Leave few mature trees. - Leave few mature trees.– ShelterwoodShelterwood - Remove in series of cuts. - Remove in series of cuts.

Harvest MethodsHarvest Methods

Strip CuttingStrip Cutting - Harvesting all trees in a - Harvesting all trees in a narrow corridor.narrow corridor.

Selective CuttingSelective Cutting - A small percentage - A small percentage of mature trees are taken in 10-20 year of mature trees are taken in 10-20 year rotation.rotation.– Can retain many characteristics of mature, Can retain many characteristics of mature,

old-growth forests.old-growth forests.

Logging roads are many times subsidized by Logging roads are many times subsidized by the government which leads to fragmentation the government which leads to fragmentation and people that need food so they grow cropsand people that need food so they grow crops

Debt-for-Nature SwapsDebt-for-Nature Swaps

Banks, governments, and lending Banks, governments, and lending institutions hold nearly $1 trillion in institutions hold nearly $1 trillion in loans to developing countries.loans to developing countries.– Conservation organizations buy debt Conservation organizations buy debt

obligations on the secondary market at obligations on the secondary market at a discount, and then offer to cancel the a discount, and then offer to cancel the debt if the debtor country will agree to debt if the debtor country will agree to protect or restore an area of biological protect or restore an area of biological importance.importance.