3 Objectives Distinguish between urban and rural land. Describe three major ways in which humans use land.Explain the concept of ecosystem services.
4 I. How We Use Land A. Land Use and Land Cover We us land for many purposes including farming, mining, recreation, and building cities and highwaysLand cover is what you find on a patch of land – it depends on how the land is used -forest, field of grain, parking lot
5 2 Types of LandUrban land – land that is covered mainly with buildings and roads-contains 2,500 or more people and usually has a government body like a city councilAny area not classified as urban is ruralRural land – land that contains relatively few people and large areas of open spaceMost land provides one or more resources that humans consume – table 1
7 B. Where We LiveUntil 1850 most people lived in rural areas -many were farmers who grew crops and raised livestock for food, clothing, and manufacturingothers managed forests, worked in local mines or mills, or manufactured necessities of life for a town
8 The Industrial Revolution changed this pattern -machinery was built that made it possible for fewer people to operate a farm or grain mill-better transportation allowed manufacturers to be located far from their customers-thousands of jobs in rural areas were eliminated so people moved to cities to find jobsUrban areas grew rapidly in the 20th century and spread over more land-today most people in the world live in urban areas-happened rapidly in developed countries between 1880 and 1950-now happening rapidly in developing countries
10 C. The Urban-Rural Connection Whether people live in the cities or countryside, they are dependent on the resources produced in rural areas-these resources include clean drinking water, fertile soil and land for crops, trees for wood and paper and much of the oxygen we breathe
12 Ecosystem servicesEcosystem services – the resources that are produced by natural and artificial ecosystems-examples are listed in table 2Supporting Urban areas-area of rural land is needed to support one person depends on many factors-the climate, standard of living, how efficiently resources are used-each person in a developed country uses the ecosystem services proved by about 8 hectares of land and water
14 How we compare-in the US each person uses the ecosystem services from more than 12 hectares whereas each person in Germany uses about 6 hectares worth-individuals in developing countries do not have access to all the resources for a healthy life – they may use ecosystem services from less than a hectare of land
16 ObjectivesDescribe the urban crisis, and explain what people are doing to deal with it.Explain how urban sprawl affects the environment.Question how open spaces provide urban areas with environmental benefits.Formulate how the heat-island effect occurs.Predict how people can use the geographic information system as a tool for land-use planning.
17 PredictThere are two types of land represented here, Open and Urban. One is covered with soil and vegetation, the other is covered with impermeable material.Predict which will be warmer at the end of class and record that in the margin of your notes.What is this phenomenon called?
18 II. Urban Land Use A. Urbanization Urbanization – the movement of people from rural areas to cities-people leave rural areas for more plentiful and better paying jobs in towns and cities-as urban populations have grown many small towns have grown together and formed larger urban areas -called metropolitan areas-Urban areas that have grown slowly are often relatively pleasant places to live – roads and publictransportation have been built to handle the growth so that traffic flows freely
19 Urbanization The Urban Crisis -buildings, roads, and parking lots are mixed in with green spaces and recreational areas-green spaces may provide these urban areas with much needed ecosystem services such as moderation of temperature, infiltration of rainwater runoff, and aesthetic valueThe Urban Crisis-when urban areas grow rapidly, they often run into trouble-can overwhelm the infrastructure and lead to traffic jams, substandard housing, and polluted air and water
21 Urban Needsinfrastructure – all the things that a society builds for public use-roads, sewers, railroads, bridges, canals, fire and police stations, schools, libraries, hospitals, etc.-when more people live in a city than its infrastructure can support the living conditions deteriorate causing an urban crisis
22 Urban sprawl – the rapid expansion of a city into the countryside around the city -building suburbs or housing and associated commercial buildings on the boundary of a larger town-people living in the suburbs commute to work in the city by car-suburbs build on land previously used for food production-each year in the US suburbs spread over another 1 million hectares of land
23 Development on Marginal lands -many cities were first built where there was little room for expansion-as cities grew the suburbs were often built on marginal land –land that is poorly suited for buildingOther Impacts of Urbanization-cities generate and trap more heat – roads and buildings trap more heat than vegetation does and retains heat longer-increased temperature in a city is called a heat island-heat islands can affect local weather patterns
24 What Is an Urban Heat Island? As urban areas develop, changes occur in their landscape. Buildings, roads, and other infrastructure replace open land and vegetation. Surfaces that were once permeable and moist become impermeable and dry. These changes cause urban regions to become warmer than their rural surroundings, forming an "island" of higher temperatures in the landscape
25 Why Do We Care About Heat Islands? Elevated temperature from urban heat islands, particularly during the summer, can affect a community's environment and quality of life. While some heat island impacts seem positive, such as lengthening the plant-growing season, most impacts are negative and include:More energy used for coolingPromotes ground level ozoneThermal water pollution
26 How do we prevent the Urban Heat Island increasing tree and vegetative covercreating green roofs (also called "rooftop gardens" or "eco-roofs")installing cool—mainly reflective—roofsusing cool pavements.
27 B. Urban PlanningLand-use planning – determining in advance how land will be used-where houses, businesses, and factories will be built, where land will be protected for recreation, etc.-land use planners determine the best locations for shopping malls, sewers, electrical lines, and other infrastructure
28 -making land-use plans is a complex and controversial process -federal, state, and local developers prepare detailed reports assessing the environmental impact of any projects-developers, city governments, local businesses, and citizens often disagree about land-use plansTechnological Tools-land use planners have sophisticated methods and tools available for them
29 (GIS)Geographic information system (GIS) – a computerized system for storing, manipulating, and viewing geographic data-GIS software allows a user to enter different types of data about an area and create maps – uses GPSTransportation-most cities in the US are difficult to travel in without a car-many cities have a mass transit system – have been constructed to get people where they want to go-Mass transit is a planning solution that saves energy, reduces highway congestion, reduces air pollution, and limits the loss of land to roadways and parking lots
30 Wide Open SpacesOpen space – land within an urban area set aside for scenic and recreational enjoyment-parks, public gardens, bicycle and hiking trailsGreenbelts – open spaces left in their natural condition-provide important ecological servicesHave plants that absorb carbon dioxide, produce oxygen, and filter out pollutants from air and water, keep the city cooler, reduce drainage problems by absorbing more rainwater runoff resulting in less floodingprovide places for exercise and relaxation
32 Objectives Explain the benefits of preserving farmland. Describe two ways that rangeland can be managed sustainably.Describe the environmental effects of deforestation.Explain the function of parks and of wilderness areas.
33 III. Land Management and Conservation As human populations grow, the resources of more rural land are needed to support the populationThe main categories of rural land are farmland, rangeland, forest land, national and state parks, and wilderness-we have reduced their productivity by overusing or polluting them-condition of rural land is important because of the ecological services that it provides
34 A. Farmlands Farmland is land that is used to grow crops and fruit -urban development in some places threatens some of the most productive farmland-in 1996, the US government established a national Farmland Protection Program to help state, county, andlocal governments protect farmland in danger of being developed
35 B. RangelandsRangeland – land that supports different vegetation types like grasslands, shrublands, and deserts that is not used for farming or timber production-can be arid or wet-most common use of rangelands is for the grazing of livestock like cattle, sheep, goats which are valued for their meat, milk, wool, and hides-native wildlife species also graze this land-necessary for maintaining the world’s food supply
36 Problems on the Range-rangelands in the US have become degraded by poor land management strategies-overgrazing – allowing more animals to graze in an area than the range can support -cause most damage to rangelands-when animals overgraze, too many of the plants are eaten and the land can become degraded -less desirable plant species may invade the area and replace more desirable plant species -in severe cases all vegetation is eaten-once the plants are gone there is nothing to keep the soil from eroding leading to Desertification
37 Maintaining the Range-much of the rangeland in the US is public land managed by the federal government which leases therangeland to ranchers-much of it is degraded-1978 Public Rangelands Improvement Act – enacted to reverse this trend and improve land managementpractices-sustaining the productivity of the rangeland generally means reducing overgrazing by limiting herds to sizesthat do not degrade the land
38 Rotational Grazingmay be left unused for periods of time so that the vegetation can recover-improving rangeland that has been damaged includes-killing invasive plants and planting native vegetation-fencing areas to let them recover-ranchers dig several small water holes so that livestock to not overgraze around a single water hole
39 C. Forest Lands Harvesting Trees Trees are harvested to proved products we use every day, paper, furniture, lumber and plywood for home-forest products such as maple syrup and turpentine-one of the most important services is the removal of CO2 from the airHarvesting Trees-people use enormous amounts of wood-each person in the US uses 3.5 times the worldwide average of 1,800 cm3 per person each day-each person cutting down a tree 30m tall every year
40 Treesdeveloping nation individuals depend on firewood as their main source of fuel-timber industry classifies forest lands into three categories-virgin forest – a forest that has never been cut-native forest – forest that is planted and managed-tree farms – areas where trees are planted in rows and harvested like other crops
41 two most widely-used methods of tree harvesting are -clear cutting – process of removing all the trees in an area of land -destroys established wildlife habitat and causes soil erosion-selective cutting – process of cutting and removing only middle-aged or mature trees-more expensive than clear cutting but much less destructive
43 DeforestationDeforestation – the clearing of trees from an area without replacing them-countries become severely deforested as populations expand and the demand for forest products increases-forests are cleared to convert land into farmland or to make space for roads, homes, factories, and office buildings-deforestation reduces wildlife habitat
44 Deforestation-causes soil erosion – there are not tree roots to hold the soil in place and it is easily washed or blown away-rate of deforestation is high in tropical rain forests where the soil is relatively thin-farmers who clear forests in these areas must always move from one plot of land to another and clear more forest each time they move-whether cleared for farming or wood, if trees are not replanted natural resources are steadily depleted
45 ReforestationReforestation – the process by which trees are planted to re-establish trees that have been cut down in forest land-in some places reforestation is happening faster than trees are being cut down – New England-some governments require reforestation after timber has been harvested-private organizations have established tree-planting programs on roadsides in cities
47 D. Parks and PreservesIn 1870, the first national park was established – Yellowstone National Park-today, the US has about 50 national parksPublic lands have many purposes-most are not protected as national parks-leased to private companies for logging, mining, and ranching-maintained for hunting and fishing or as wildlife refuges or for protecting endangered speciesInternational efforts have set up several hundred biosphere reserves around the world– include people in their management plan
48 WildernessUnder the US Wilderness Act of 1964, designated certain lands as wilderness areasWilderness – an area in which the land and the ecosystems it supports are protected from all exploitation-open to hiking, fishing, boating (without motors), and camping-building roads or structures and using motorized equipment are not allowed
51 Benefits of Protected Areas -without national and private parks and preserves around the world, many more species would be extinct-provide recreation for people-only place where unspoiled forests, deserts, or prairies remain-serve as outdoor classrooms and research labs where people can learn more about the natural world
52 Threats to protected areas -constant battle between our conservation efforts and the growing population-litter and traffic jams, rangelands, mining, logging, oil and gas drilling operations, factories, power plants, and urban areas are often close enough to the park to affect them-preserved areas are affected by climate change and air and water pollution
53 Threats to protected areas -wilderness areas have limits to the number of people permitted in some areas if at all-volunteer programs to pick up trash, build trails, control invading or exotic species, and educate the visiting public