Climate and Terrestrial Biodiversity Chapter 5 Climate and Terrestrial Biodiversity

Chapter Overview Questions What factors the earth’s climate? How does climate determine where the earth’s major biome’s are found? What are the major types of desert biomes? What are the major types of grassland biomes?

Chapter Overview Questions (cont’d) What are the major types of forest and mountain biomes? How have human activities affected the world’s desert, grassland, forest, and mountain biomes?

Core Case Study Blowing in the Wind: A Story of Connections Wind connects most life on earth. Keeps tropics from being unbearably hot. Prevents rest of world from freezing. Figure 5-1

Weather and climate Weather is a local area’s short-term physical conditions such as temperature and precipitation. Climate is a region’s average weather conditions over a long time. Latitude and elevation help determine climate. Average temp and average precipitation are two main factors. “Climate is what we expect, weather is what we get” – Mark Twain.

Earth’s Current Climate Zones Figure 5-2

Distributing Heat Global air circulation is affected by the uneven heating of the earth’s surface by solar energy, seasonal changes in temperature and precipitation. Four major factors determine global air circulation patterns: Uneven heating of the earth’s surface by the sun Seasonal changes in temperature and precipitation Rotation of the earth on its axis causes Coriolis effect Properties of air, water and land (convection currents) Figure 5-3

(sun aims directly at equator) Winter (northern hemisphere tilts away from sun) Spring (sun aims directly at equator) 23.5 ° Solar radiation Summer (northern hemisphere tilts toward sun) Figure 5.3 Natural capital: as the planet makes its annual revolution around the sun on an axis tilted about 23.5°, various regions are tipped toward or away from the sun. The resulting variations in the amount of solar energy reaching the earth create the seasons in the northern and southern hemispheres. Fall (sun aims directly at equator) Fig. 5-3, p. 102

Coriolis Effect Global air circulation is affected by the rotation of the earth on its axis. Atmospheric regions called cells are made from belts of prevailing winds (major winds continuously blowing) that distribute heat and moisture Six giant convection cells on earth Figure 5-4

Tropical deciduous forest Cold, dry air falls Cell 3 North Moist air rises — rain Polar cap Cell 2 North Arctic tundra Evergreen coniferous forest 60° Cool, dry air falls Temperate deciduous forest and grassland 30° Desert Cell 1 North Tropical deciduous forest Moist air rises, cools, and releases Moisture as rain 0° Equator Tropical rain forest Tropical deciduous forest 30° Desert Figure 5.6 Natural capital: global air circulation and biomes. Heat and moisture are distributed over the earth’s surface by vertical currents, which form six giant convection cells at different latitudes. The resulting uneven distribution of heat and moisture over the planet’s surface leads to the forests, grasslands, and deserts that make up the earth’s biomes. Cell 1 South Temperate deciduous forest and grassland Cool, dry air falls 60° Cell 2 South Polar cap Cold, dry air falls Moist air rises — rain Cell 3 South Fig. 5-6, p. 103

Heat released radiates to space Moist surface warmed by sun LOW PRESSURE HIGH PRESSURE Heat released radiates to space Condensation and precipitation Cool, dry air Falls, is compressed, warms Rises, expands, cools Warm, dry air Hot, wet air Figure 5.5 Natural capital: transfer of energy by convection in the troposphere. Convection occurs when hot and wet warm air rises, cools, and releases moisture as precipitation and heat (right side). Then the more dense cool and dry air sinks, gets warmer, and picks up moisture as it flows across the earth’s surface to begin the cycle again. Flows toward low pressure, picks up moisture and heat HIGH PRESSURE Moist surface warmed by sun LOW PRESSURE Fig. 5-5, p. 103

Ocean Currents Ocean currents influence climate by distributing heat from place to place and mixing and distributing nutrients. Flow clockwise in northern hemisphere, counterclockwise in southern. Gulf Stream transports 25 times more water than all of the world’s rivers combined. Figure 5-7

(b) The earth's surface absorbs much of the incoming solar radiation (a) Rays of sunlight penetrate the lower atmosphere and warm the earth's surface. (b) The earth's surface absorbs much of the incoming solar radiation and degrades it to longer-wavelength infrared (IR) radiation, which rises into the lower atmosphere. Some of this IR radiation escapes into space as heat, and some is absorbed by molecules of greenhouse gases and emitted as even longer-wavelength IR radiation, which warms the lower atmosphere. (c) As concentrations of greenhouse gases rise, their molecules absorb and emit more infrared radiation, which adds more heat to the lower atmosphere. Figure 5.7 Natural capital: the natural greenhouse effect. When concentrations of greenhouse gases in the atmosphere rise, the average temperature of the troposphere rises. (Modified by permission from Cecie Starr, Biology: Concepts and Applications, 4th ed., Pacific Grove, Calif.: Brooks/Cole, 2000) Fig. 5-7, p. 104

Ocean Currents: Distributing Heat and Nutrients Global warming: Considerable scientific evidence and climate models indicate that large inputs of greenhouse gases from anthropogenic activities into the troposphere can enhance the natural greenhouse effect and change the earth’s climate in your lifetime.

Topography and Local Climate: Land Matters Interactions between land and oceans and disruptions of airflows by mountains and cities affect local climates. Figure 5-8

Biomes Different climates lead to different communities of organisms, especially vegetation. Biomes – large terrestrial regions characterized by similar climate, soil, plants, and animals. Each biome contains many ecosystems whose communities have adapted to differences in climate, soil, and other environmental factors. Climates have changed over the earth’s history. Temperature, precipitation, and soil type are the most important factors in producing the type of biome. Biomes are not uniform; they consist of a mosaic of patches

Tropic of Cancer Equator Tropic of Capricorn High mountains Polar ice Polar grassland (arctic tundra) Tropic of Capricorn Figure 5.9 Natural capital: the earth’s major biomes—the main types of natural vegetation in various undisturbed land areas—result primarily from differences in climate. Each biome contains many ecosystems whose communities have adapted to differences in climate, soil, and other environmental factors. Human ecological footprints (Figures 3 and 4 on pp. S12–S15 in Supplement 4) have removed or altered much of the natural vegetation in some areas for farming, livestock grazing, lumber and fuelwood, mining, and construction. Temperate grassland Tropical grassland (savanna) Chaparral Coniferous forest Temperate deciduous forest Tropical forest Desert Fig. 5-9, p. 106

Decreasing precipitation Cold Polar Tundra Subpolar Temperate Coniferous forest Decreasing temperature Desert Deciduous Forest Grassland Tropical Chaparral Figure 5.10 Natural capital: average precipitation and average temperature, acting together as limiting factors over a period of 30 or more years, determine the type of desert, grassland, or forest biome in a particular area. Although the actual situation is much more complex, this simplified diagram explains how climate determines the types and amounts of natural vegetation found in an area left undisturbed by human activities. (Used by permission of Macmillan Publishing Company, from Derek Elsom, The Earth, New York: Macmillan, 1992. Copyright © 1992 by Marshall Editions Developments Limited) Hot Desert Wet Savanna Rain forest Dry Tropical seasonal forest Scrubland Decreasing precipitation Fig. 5-10, p. 107

Effects of elevation and latitude on biomes Parallel changes occur in vegetation type occur when we travel from the equator to the poles or from lowlands to mountaintops. Figure 5-11

DESERT BIOMES Deserts are areas where evaporation exceeds precipitation. Deserts have little precipitation and little vegetation. Found in tropical, temperate and polar regions. Desert plants have adaptations that help them stay cool and get enough water. Cover about 30% of the earth’s land surface

DESERT BIOMES Variations in annual temperature (red) and precipitation (blue) in tropical, temperate and cold deserts. Figure 5-12

Tropical Desert Month Mean monthly temperature (C) Freezing point Mean monthly temperature (C) Mean monthly precipitation (mm) Figure 5.12 Natural capital: climate graphs showing typical variations in annual temperature (red) and precipitation (blue) in tropical, temperate, and cold deserts. Top photo shows a popular but destructive SUV rodeo in Saudi Arabia (tropical desert). Center photo shows saguaro cactus in the United States (temperate desert). Bottom photo shows a Bactrian camel in Mongolia’s Gobi (cold) desert. Month Fig. 5-12a, p. 109

Temperate Desert Month Mean monthly temperature (C) Freezing point Mean monthly temperature (C) Mean monthly precipitation (mm) Figure 5.12 Natural capital: climate graphs showing typical variations in annual temperature (red) and precipitation (blue) in tropical, temperate, and cold deserts. Top photo shows a popular but destructive SUV rodeo in Saudi Arabia (tropical desert). Center photo shows saguaro cactus in the United States (temperate desert). Bottom photo shows a Bactrian camel in Mongolia’s Gobi (cold) desert. Month Fig. 5-12b, p. 109

Polar Desert Month Mean monthly precipitation (mm) Freezing point Mean monthly precipitation (mm) Mean monthly temperature (°C) Figure 5.12 Natural capital: climate graphs showing typical variations in annual temperature (red) and precipitation (blue) in tropical, temperate, and cold deserts. Top photo shows a popular but destructive SUV rodeo in Saudi Arabia (tropical desert). Center photo shows saguaro cactus in the United States (temperate desert). Bottom photo shows a Bactrian camel in Mongolia’s Gobi (cold) desert. Month Fig. 5-12c, p. 109

Deserts The flora and fauna in desert ecosystems adapt to their environment through their behavior and physiology. Adaptations include two main themes: Beat the heat Every drop of water counts Figure 5-13

Desert adaptations Plants: Animals: Fragile ecosystems Waxy leaves Deep roots Store water Open stomatta only at night Animals: Hide during day Thick outer covering to prevent water loss Get water from dew or food Fragile ecosystems Soil nutrients take a long time to recover

GRASSLANDS AND CHAPARRAL BIOMES Variations in annual temperature (red) and precipitation (blue). Figure 5-14

Tropical grassland (savanna) Freezing point Mean monthly temperature (C) Mean monthly precipitation (mm) Figure 5.14 Natural capital: climate graphs showing typical variations in annual temperature (red) and precipitation (blue) in tropical, temperate, and polar (arctic tundra) grasslands. Top photo shows wildebeests grazing on a savanna in Maasai Mara National Park in Kenya, Africa (tropical grassland). Center photo shows wildflowers in bloom on a prairie near East Glacier Park in the U.S. state of Montana (temperate grassland). Bottom photo shows arctic tundra with caribou in Alaska’s Arctic National Wildlife Refuge (polar grassland). Month Fig. 5-14a, p. 112

Temperate grassland Month Mean monthly temperature (C) Freezing point Mean monthly temperature (C) Mean monthly precipitation (mm) Figure 5.14 Natural capital: climate graphs showing typical variations in annual temperature (red) and precipitation (blue) in tropical, temperate, and polar (arctic tundra) grasslands. Top photo shows wildebeests grazing on a savanna in Maasai Mara National Park in Kenya, Africa (tropical grassland). Center photo shows wildflowers in bloom on a prairie near East Glacier Park in the U.S. state of Montana (temperate grassland). Bottom photo shows arctic tundra with caribou in Alaska’s Arctic National Wildlife Refuge (polar grassland). Month Fig. 5-14b, p. 112

Polar grassland (arctic tundra) Freezing point Mean monthly temperature (C) Mean monthly precipitation (mm) Figure 5.14 Natural capital: climate graphs showing typical variations in annual temperature (red) and precipitation (blue) in tropical, temperate, and polar (arctic tundra) grasslands. Top photo shows wildebeests grazing on a savanna in Maasai Mara National Park in Kenya, Africa (tropical grassland). Center photo shows wildflowers in bloom on a prairie near East Glacier Park in the U.S. state of Montana (temperate grassland). Bottom photo shows arctic tundra with caribou in Alaska’s Arctic National Wildlife Refuge (polar grassland). Month Fig. 5-14c, p. 112

GRASSLANDS AND CHAPARRAL BIOMES Grasslands (prairies) occur in areas too moist for desert and too dry for forests. Savannas are tropical grasslands with scattered tree and herds of hoofed animals. Migrations to find food and water in response to seasonal changes. Plants can survive extreme moisture and temperature levels.

Temperate Grasslands The cold winters and hot dry summers have deep and fertile soil that make them ideal for growing crops and grazing cattle. Short-grass and tall-grass praries. Figure 5-15

Golden eagle Pronghorn antelope Coyote Grasshopper sparrow Grasshopper Blue stem grass Prairie dog Figure 5.15 Natural capital: some components and interactions in a temperate tall-grass prairie ecosystem in North America. When these organisms die, decomposers break down their organic matter into minerals that plants can use. Colored arrows indicate transfers of matter and energy between producers, primary consumers (herbivores), secondary or higher level consumers (carnivores), and decomposers. Organisms are not drawn to scale. Bacteria Fungi Prairie Coneflower Producer to primary consumer Primary to secondary consumer Secondary to higher-level consumer All producers and consumers to decomposers Fig. 5-15, p. 113

Polar Grasslands Polar grasslands are covered with ice and snow except during a 6-8 week summer. Permafrost can form: underground soil that stays frozen for more than 2 consecutive years. Global warming has melted some permafrost, releasing CH4. Soil recovers slowly; biome is fragile. Figure 5-17

Chaparral Chaparral has a moderate climate but its dense thickets of spiny shrubs are subject to periodic fires. Thin soil, not very fertile. Figure 5-18

FOREST BIOMES Variations in annual temperature (red) and precipitation (blue) in tropical, temperate, and polar forests. Forests have enough precipitation to support stands of trees and are found in tropical, temperate, and polar regions. Figure 5-19

Tropical rain forest Month Mean monthly temperature (C) Freezing point Mean monthly temperature (C) Mean monthly precipitation (mm) Figure 5.19 Natural capital: climate graphs showing typical variations in annual temperature (red) and precipitation (blue) in tropical, temperate, and polar (cold) forests. Top photo shows the closed canopy of a tropical rain forest in the western Congo Basin of Gabon, Africa. Middle photo shows a temperate deciduous forest in the U.S. state of Rhode Island during the fall. Photo 9 in the Detailed Contents shows this same area of forest during winter. Bottom photo shows a northern coniferous forest in the Malheur National Forest and Strawberry Mountain Wilderness in the U.S. state of Oregon. Month Fig. 5-19a, p. 116

Temperate deciduous forest Freezing point Mean monthly temperature (C) Mean monthly precipitation (mm) Figure 5.19 Natural capital: climate graphs showing typical variations in annual temperature (red) and precipitation (blue) in tropical, temperate, and polar (cold) forests. Top photo shows the closed canopy of a tropical rain forest in the western Congo Basin of Gabon, Africa. Middle photo shows a temperate deciduous forest in the U.S. state of Rhode Island during the fall. Photo 9 in the Detailed Contents shows this same area of forest during winter. Bottom photo shows a northern coniferous forest in the Malheur National Forest and Strawberry Mountain Wilderness in the U.S. state of Oregon. Month Fig. 5-19b, p. 116

Polar evergreen coniferous forest (boreal forest, taiga) Freezing point Mean monthly temperature (C) Mean monthly precipitation (mm) Figure 5.19 Natural capital: climate graphs showing typical variations in annual temperature (red) and precipitation (blue) in tropical, temperate, and polar (cold) forests. Top photo shows the closed canopy of a tropical rain forest in the western Congo Basin of Gabon, Africa. Middle photo shows a temperate deciduous forest in the U.S. state of Rhode Island during the fall. Photo 9 in the Detailed Contents shows this same area of forest during winter. Bottom photo shows a northern coniferous forest in the Malheur National Forest and Strawberry Mountain Wilderness in the U.S. state of Oregon. Month Fig. 5-19c, p. 116

Tropical Rain Forest Tropical rain forests have heavy rainfall and a rich diversity of species. Found near the equator. Have year-round uniformity warm temperatures and high humidity. Vast amount of biodiversity. High net primary productivity. 2% of earth’s land surface, half of the earth’s terrestrial species reside here. Figure 5-20

Tropical Rain Forest Filling such niches enables species to avoid or minimize competition and coexist Figure 5-21

Temperate Deciduous Forest Most of the trees survive winter by dropping their leaves, which decay and produce a nutrient-rich soil. Figure 5-22

Evergreen Coniferous Forests Consist mostly of cone-bearing evergreen trees that keep their needles year-round to help the trees survive long and cold winters. Figure 5-23

Temperate Rain Forests Coastal areas support huge cone-bearing evergreen trees such as redwoods and Douglas fir in a cool moist environment. Figure 5-24

MOUNTAIN BIOMES High-elevation islands of biodiversity Often have snow-covered peaks that reflect solar radiation and gradually release water to lower-elevation streams and ecosystems. Plants hold back erosion. Contain majority of earth’s forests. Figure 5-25

Human impact Human activities have damaged or disturbed more than half of the world’s terrestrial ecosystems. Humans have had a number of specific harmful effects on the world’s deserts, grasslands, forests, and mountains. Humans use, waste, or destroy 10-55% of the net primary productivity of earth’s terrestrial ecosystems. 60% of the world’s major terrestrial ecosystems are being degraded/used unsustainably.

Natural Capital Degradation Desert Large desert cities Soil destruction by off-road vehicles Soil salinization from irrigation Figure 5.26 Natural capital degradation: major human impacts on the world’s deserts. QUESTION: What are three direct and three indirect harmful effects of your lifestyle on deserts? Depletion of groundwater Land disturbance and pollution from mineral extraction Fig. 5-26, p. 123

Natural Capital Degradation Grasslands Conversion to cropland Release of CO2 to atmosphere from grassland burning Overgrazing by livestock Figure 5.27 Natural capital degradation: major human impacts on the world’s grasslands. Some 70% of Brazil’s tropical savanna—once the size of the Amazon—has been cleared and converted to the world’s biggest grain growing area. QUESTION: What are three direct and three indirect harmful effects of your lifestyle on grasslands? Oil production and off-road vehicles in arctic tundra Fig. 5-27, p. 123

Natural Capital Degradation Forests Clearing for agriculture, livestock grazing, timber, and urban development Conversion of diverse forests to tree plantations Damage from off-road vehicles Figure 5.28 Natural capital degradation: major human impacts on the world’s forests. QUESTION: What are three direct and three indirect effects of your lifestyle on forests? Pollution of forest streams Fig. 5-28, p. 124

Natural Capital Degradation Mountains Agriculture Timber extraction Mineral extraction Hydroelectric dams and reservoirs Increasing tourism Urban air pollution Figure 5.29 Natural capital degradation: major human impacts on the world’s mountains. QUESTION: What are three direct and three indirect harmful effects of your lifestyle on mountains? Increased ultraviolet radiation from ozone depletion Soil damage from off-road vehicles Fig. 5-29, p. 124