- Количество слайдов: 31
Biomes Under Pressure • • Forests and woodlands Tropical forests Oceans Coral reefs and mangroves
World Wood Consumption
Causes of Deforestation • Economic development • Human population growth
Frontier Forests 8, 000 Years Ago Frontier Forest = “Old Growth” Forest, which never having been cut down and cleared by humans, they are in balance with natural disturbance events such as fire, winds, etc…
Frontier Forests Today Very few forests remain untouched by humans and our practices of large scale clearing for wood and agriculture lands.
North American Frontiers Low or no threat Medium or high threat Non frontier forests Unassessed for threat Non-Frontier Forest are also called “Second Growth” Forests, meaning they have growth back at after at least one clearing.
www. globalforestwatch. org
Man wants more farmland for livestock and crops. Cameroon in 1959 Non-Forest Unprotected Forest Protected Forest Logged or Logging
Cameroon in 1971 Non-Forest Unprotected Forest Protected Forest Logged or Logging
Cameroon in 1995 Non-Forest Unprotected Forest Protected Forest Logged or Logging
Cameroon in 1999 Non-Forest Unprotected Forest Protected Forest Logged or Logging Today, 80% of Cameroon’s Unprotected Forests are in Logging Areas or Concessions
Affects of Deforestation (Clear Cutting) Loss of forests leads to: More or Less Productivity Nutrient recycling Biodiversity Soil erosion Evapotranspiration Air pollution
Sustainable Forest Management • • Manage for sustainable outcomes Responsible practices (teach others) Protect the health of the forest Recognize and protect unique forest ecosystems. • Continuous improvement (strive to be better forest managers; be adaptive)
New Forestry Practices • Cut trees less frequently • Leave wider buffer zones along waterways • Leave dead logs and debris • Protect broader landscapes • Build no new roads until damage to old ones is addressed • Added-value products (use of species other than wood/lumber species)
Loss of Tropical Rainforests – Why? • Colonization: consolidation of agricultural lands • Huge national debts • Fast food chains and cheap hamburger
Conserving Tropical Rainforests • Ecotourism • Extractive reserves & Valueadded products • Management by indigenous people • Rubber, coffee & cocoa plantations • Sustainable logging • Carbon sequestration credits
Ocean Ecosystems 75% of the Earth’s surface An international commons?
Global Fish Harvests Overfishing one species leads to shift to catch other less desirable species elsewhere. 100 million metric tons of food on a sustained basis?
Fisheries Problems Too many boats High technology Too few fish
Magnuson-Stevens Fishery Conservation and Management Act 1976 • • Gave federal government authority to manage fisheries Claimed the area between 3 and 200 miles off shore as the “Exclusive Economic Zone” • Designed to eliminate foreign fishing • Designed to restore and conserve fish
Impacts of Magnuson-Stevens Act • Swapped foreign with American exploiters • Huge conflict of interest among council members • Endangerment of 236 fish species
Fisheries in Distress Georges Bank Cod Fishery Collapse: Regional management council versus NMFS, an example of regional politics over sound science in late 1970’s; 197 dramatic solutions = half-time, 2/3 area fished; buy-out program.
Sustainable Fisheries Act • The 1996 reauthorization of the Magnuson Act. • Mandates that fish stocks be rebuilt (reestablished) • Management plans and yields be based on sound scientific data • Steps be taken to minimize “by-catch”
Mangrove Forest: trees adapted to saltwater and flooded soils.
Mangroves • Protects coasts from storm damage and erosion • Forms rich refuge and nursery for marine fish • Prevents sediments and excess nutrients getting to Coral Reefs • Shrimp farming and residential development are leading causes of clearing.
Coral Reefs as Resources for Man: • Important food sources for local people • Wave erosion control • Great diversity of marine vertebrates and invertebrates
Sources of Damage to Coral Reefs: • Climate Change – Warmer waters – (Coral Bleaching Hot Spots) • Sedimentation and Eutrophication – Coastal development – Shrimp aquaculture – Logging • Over-Fishing – Islander poverty – Northern Demand • Habitat Destruction/Alteration – “Loving it to death” – anchor and diver damage
Marine Sanctuaries [Photo: Northwestern Hawaiian Islands Coral Reef Ecosystem Reserve]
Belize Case Study • About 70% Forest Remains • Second largest barrier reef in the world. • Tourism industry matches sugar Cane production as leading industry and revenue generator in Belize. • Approximately 45% of land area as park, reserves, or private land trusts. • Numerous marine sanctuaries!