Environmental Problems, Their Causes, and Sustainability 1

CaribouLong-tailed jaegerGrizzly bearFigure 6-26 Natural capital: somecomponents and interactions in anarctic tundra (polar grassland)ecosystem. When these organismsdie, decomposers break down theirorganic matter into minerals thatplants use. Colored arrows indicatetransfers of matter and energy betweenproducers, primary consumers(herbivores), secondary, orhigher-level, consumers (carnivores),and decomposers. Organismsare not drawn to scale.MosquitoSnowy owlHorned larkArcticfoxWillow ptarmiganDwarfwillowLemmingMountaincranberryMoss campionProducerto primaryconsumerPrimaryto secondaryconsumerSecondary tohigher-levelconsumerAll producers andconsumers todecomposersmanent snow line on high mountains (Figure 6-18,left). The vegetation is similar to that found in arctictundra, but it gets more sunlight than arctic vegetationand has no permafrost layer.Figure 6-27 (p. 120) lists major human impacts ongrasslands. What are the direct and indirect effects ofyour lifestyle on grassland biomes?What Is Chaparral? Great Place to Livebut Beware of Fires and MudslidesThis temperate shrubland has a wonderful climatebut is subject to fires in the fall followed by floodingand mudslides.In many coastal regions that border on deserts, such assouthern California and the Mediterranean, we find abiome known as temperate shrubland or chaparral.Closeness to the sea provides a slightly longer winterrainy season than nearby temperate deserts have, andfogs during the spring and fall reduce evaporation.Chaparral consists mostly of dense growths oflow-growing evergreen shrubs and occasional smalltrees with leathery leaves that reduce evaporation.During the long, hot and dry summers, chaparral vegetationbecomes very dry and highly flammable. In thefall, fires started by lightning or human activitiesspread with incredible swiftness.Research reveals that chaparral is adapted to andmaintained by periodic fires. Many of the shrubs storefood reserves in their fire-resistant roots and haveseeds that sprout only after a hot fire. With the firstrain, annual grasses and wildflowers spring up andhttp://biology.brookscole.com/miller14119