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 1 st 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 –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 1 st 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 (2004)

Manufacture and Use of Banned Pesticides - The Dirty Dozen