APES Day 72! Respond to the quote by Adam Smith from The Wealth of Nations, “No society can surely be flourishing and happy, of which the far greater part of the members are poor and miserable.” Please have your notes out…what are the main causes of desertification? Biomes affected?

Overgrazing and Land Degradation About one-third of the world’s rangeland is severely degraded by over-grazing. –Grazing animals usually exhibit selective grazing, removing preferred species and leaving non-preferred species to survive and reproduce. Gradually, nutritional value of forage declines. –Denudation of ground leads to desiccation and desertification.

Forage Conversion by Domestic Animals Ruminants are efficient at turning plant material into protein because bacterial digestion in their multiple stomachs allows utilization of cellulose and other complex carbohydrates. –Worldwide, 85% of ruminant forage comes from native rangelands and pasture. –In US only 15% of livestock feed comes from native grasslands. 90% of our total grain crop is used for livestock feed.

Rangelands in the United States US has approximately 319 million ha of rangeland. –Most in the West About 60% is privately owned. Only 2% of cattle and 10% of sheep graze on public land. –BLM manages more land than any other agency in the US. Strong agency inclination towards resource utilization.

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.

How do we manage forests?

Swidden Agriculture Can be ecologically sound and sustainable if performed carefully and in moderation. Slash and Burn –Hectare plot cleared, dried, and burned. Ashes used to prepare seedbed. –Fast-growing crops planted to control erosion, shade crops, and anchor soil. Cropped intensively for 1-2 years, and then rested years.

Logging and Land Invasions Other major source of forest destruction is logging and subsequent invasion. –Bulldozed roads make it possible for large numbers of immigrants to move into the forest in search of farmland. Forest clearing leads to river degradation through increased silt and sediment flow.

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

Harvest Methods 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. –Coppicing - Encourage stump-sprouts. –Seed-Tree - Leave few mature trees. –Shelterwood - Remove in series of cuts.

Harvest Methods Strip Cutting - Harvesting all trees in a narrow corridor. Selective Cutting - A small percentage of mature trees are taken in year rotation. –Can retain many characteristics of mature, old-growth forests.

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

Debt-for-Nature Swaps Banks, governments, and lending institutions hold nearly $1 trillion in loans to developing countries. –Conservation organizations buy debt obligations on the secondary market at a discount, and then offer to cancel the debt if the debtor country will agree to protect or restore an area of biological importance.