The Urban Ecosystem Chapter 4.7 Cities Cities cause a lot of air and water pollution Air pollutions comes from car exhaust, burning fuels, and gases from industries Water pollution comes from biological, commercial and industrial waste People who live in cities rely on: Forestry and mining for a variety of materials (ie. Lumber for furniture) Agroecosysems for food (ie. Farm land crops) Natural ecosystems for recreation (ie. A park) Urban vs. Natural Ecosystems FeatureUrbanNatural FeatureUrbanNatural -surface features -buildings, roadways, parking lots -dominated by plants FeatureUrbanNatural -plant species -not common -non-native species like grass, small flowers -highly dense and diverse FeatureUrbanNatural -common animal species -low diversity/low abundance -dogs, cats, mice, pigeons, etc -high density, highly diverse Feature UrbanNatural -water cycle -surface waters goes into drains/sewers -surfaces are impenetrable to water -humans consume lots of water -waste water returns to surface -surface water goes to streams/lakes -rainfall is absorbed at surface -water drains through soil to groundwater FeatureUrbanNatural -flow of materials -influx of material goods to support humans -human body waste collected, treated and disposed in environment -household/commercial waste disposed in environment -minimal recycling -natural nutrient cycles take place in ecosystems FeatureUrbanNatural -food webs-dependent on importing food from outside -complex natural food webs FeatureUrbanNatural -sustainability-cannot be sustained without inputs from other ecosystems -independently sustainable We Need Nature Humans cannot survive in an isolated urban environment. We rely on outside natural ecosystems. City planners and politicians have had to start thinking about greener cities; they must consider the impact of human actions on ecosystems Ie. Banning plastic bags What can we do? ActionBenefit -composting programs -reduces landfills, provides fertilizer -use LED traffic lights -reduces energy consumption -promote public transit-reduce pollution - promote green roofs-improves air quality