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Unit VI Land Use Land Breakdown US Land Use • 55% of land in US is privately owned • Remaining land is owned by the government – Most federal land is in Alaska and western states Land Use Wilderness Parks and Wildlife Refuges • Wilderness – A protected area of land in which no human development is permitted • Wilderness Act (1964) – Set aside federally owned land • Managed by NPS, USFS, FWS & BLM National Parks • 1st Park 1872 – Yellowstone • National Park Service – Created in 1916 • Currently includes 58 parks • Primary goal – Teach people about the natural environment, management of natural resources and history of a site National Parks • Threats to U.S. Parks – – – – Crime & Vandalism Traffic jams Pollution of the soil, water and air Resource violations • Natural Regulation – Policy to let nature take its course – No culling wildlife or suppressing wildfire Wildlife Refuge • National Wildlife Refuge System – First one in 1870 • Lake Merritt, CA – First National 1903 • Pelican Island • Represent all major ecosystems found in the US • Mission – To preserve lands and waters for the conservation of fishes, wildlife and plants of the US National Forests • Managed for multiple uses – – – – Timber harvest Livestock forage Water resource and watershed protection Mining, hunting, fishing, etc. • Road building is an issue – Provides logging companies with access to forest • Clearcutting is an issue Forest Management • Traditional Forest Management – Low diversity - monocultures – Managed for timber production Forest Management • Ecological Sustainable Forest Management – – – – – Environmentally balanced Diverse trees Prevent soil erosion Preserve watersheds Wildlife corridors - unlogged Harvesting Trees Deforestation • Results of Deforestation – – – – – – – Decreased soil fertility Uncontrolled soil erosion Production of hydroelectric power (silt build up behind dams) Increased sedimentation of waterways Formation of deserts Extinction of species Global climate changes Rangelands • Rangelands – Land that is not intensively managed and is used for grazing livestock Rangelands • Overgrazing leaves ground barren – Animals exceed land’s carrying capacity • Land degradation – Natural or human-induced process that decreases future ability of land to support crops or livestock • Desertification – Degradation of once fertile land into nonproductive desert Rangelands • Make up 30% of total US land area • Pressure from developers to subdivide • Public rangeland managed by: – Taylor Grazing Act (1934) – Federal Land Policy and Management Act (1976) • Conditions of public rangeland are slowly improving Agricultural Land • US has 300 million acres of prime farmland • Suburban sprawl – Parking lots – Housing developments – Shopping malls Food Production Methods • Croplands – provides ~75% of world’s food supply – mostly grain production • Rangelands – provides ~15% of world’s food supply – includes meat and meat products • Fisheries – provides ~7% of world’s food supply – primarily oceanic fishes World Food Security • Feeding growing population is difficult • Annual grain production (left) has increased since 1970 • Grain per person has not (right) Crop Production Animals as Food • Constitute 40% of the calories consumed in developed countries • Only comprise 5% of calories consumed in developing countries Principle Types of Agriculture • Industrialized agriculture – Modern agriculture methods that require large capital input, and less land and labor – Uses large amounts of energy, water, fertilizers, & pesticides – practiced on ~25% of all cropland – produces ~80% of world’s food supplies Principle Types of Agriculture • Subsistence Agriculture – Traditional agricultural methods, which are dependent on labor and large amounts of land – Most common type of agricultural practice • practiced by ~40% of world’s population • shifting cultivation, slash and burn agriculture, nomadic herding, intercropping Challenges of Producing More Crop and Livestock • Domestication and Genetic Diversity – Domestication of crops and livestock causes a loss of genetic diversity – Farmer selects and propagates animals with desirable agricultural characteristics Challenges of Producing More Crop and Livestock • Increasing Crop Yields – Food production increased in developed countries (wheat(left) – Pesticides – Selective breeding Challenges of Producing More Crop and Livestock • Increasing Livestock Yields – Hormone supplements • US and Canada • Not used in Europe – Antibiotics • 40% of antibiotics produced in US are used in livestock operations • Problems with increased bacteria resistance Antibiotic Use and Resistance Genetic Engineering • Manipulation of genes by taking specific gene from a cell of one species and placing it into the cell of an unrelated species Genetically Modified Organisms (GMOs) • Add beneficial characteristics to crops – – – – Additional nutrition Resistance to pests Drought resistances (below) Herbicides Genetically Modified Organisms (GMOs) Safety in Genetic Engineering • Studies have shown them to be safe for human consumption • Concerns about GMO seed or pollen spreading in wild • GMOs are not currently labeled – Push for legislation in certain states or communities • Backlash against GMOs – Banned in EU Environmental Impacts of Agriculture Sustainable Agriculture • Examples: – – – – – Natural Predator-prey relationships instead of pesticides Crop selection Crop rotation and conservation tillage Supplying nitrogen with legumes Organic agriculture • Integrated Pest Management (IPM) Fisheries • No nation lays claim to open ocean – Resource susceptible to overuse and degradation • commons Fisheries • Overharvesting – Many species are at point of severe depletion – 62% of world’s fish stock are in need of management action – Sophisticated fishing equipment – Bycatch killed off Commercial Fishing Methods • • • • • Trawling Purse-Seine Longlining Drift Net Aquaculture World Seafood Harvest Fisheries of the World - Problems • Ocean Pollution - dumping ground – – – – Oil Heavy metals Deliberate litter dumping Stormwater runoff from cities and agricultural areas • Aquaculture – Growing of aquatic organisms for human consumption – Great potential to supply food Fisheries of the World - Problems • Aquaculture (continued) – Locations of fisheries may hurt natural habitats – Produce waste that pollutes adjacent water Pesticides • Broad spectrum pesticide – A pesticide that kills a variety of organisms, not just the targeted organisms • 1st Generation Pesticide – Inorganic compounds – Botanicals: plant derived pesticides (right) Pesticides • Second generation pesticide – Synthetic poison – Ex: DDT Problems with Pesticides • Evolution of Genetic Resistance – Pest populations are evolving resistance to pesticides (right) Pesticide Resistance • Pesticide Treadmill – Cost of applying pesticide increases – While their effectiveness decreases • Resistance Management – Strategies for managing genetic resistance in order to maximize the period in which a pesticide is useful Problems with Pesticides • Imbalances the Ecosystem – Spraying to kill insects can affect birds, rabbits, etc. – Despite 33-fold increase in pesticides since the 1940s, crop loss has not decreased much Problems with Pesticides • Persistence, Bioaccumulation, and Biomagnification – Bioaccumulation: The buildup of a persistent pesticide or other toxic substance in an organisms body – Biomagnication: Increased concentration of toxic chemicals in tissues of organisms at higher trophic levels Systems Approach - Integrated Pest Management (IPM) • IPM – Combination of pest control methods that keeps pest population low without economic loss • Conventional pesticides are used sparingly when other methods fail Integrated Pest Management Systems Approach - Integrated Pest Management (IPM) • Rice Production in Indonesia Manufacture and Use of Banned Pesticides • Some US companies still make banned or seriously restricted pesticides – Product is exported • May lead to the importation of food tainted with banned pesticides • Global ban of persistent organic pollutants – Stockholm Convention on Persistent Organic Pollutants POPS (2004) Manufacture and Use of Banned Pesticides - The Dirty Dozen International Regulations • Endangered Species Act- prohibits the harm or harvesting of endangered species; protects habitats • Marine Mammal Protection Act- protection and conservation of marine mammals (whales, dolphins, etc)
