4. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Enger & Smith Environmental Science A Study of Interrelationships Twelfth Edition Unit 5 - Chapter 6, Part 2 Kinds of Ecosystems and Communities David Rude

5. In the News  A strain of cockroaches in Europe has evolved to outsmart the sugar traps used to eradicate them.  American scientists found that the mutant cockroaches had a "reorganized" sense of taste, making them perceive the glucose used to coat poisoned bait not as sweet but rather as bitter.

6. Kinds of Ecosystems and Communities

8. Biomes: Major Types of Terrestrial Climax Communities Biomes of the world

9. The Effect of Elevation on Climate and Vegetation  Temperature and precipitation Warmest near equator, cooler toward the poles Temperature decreases as altitude increases Moving from sea level to mountain tops –Possible to pass through a series of biomes –Similar moving from the equator to the North Pole

10. The Effect of Elevation on Climate and Vegetation Relationship between height above sea level, latitude, and vegetation.

12. Desert  Deserts Areas that average less than 25 cm annual precipitation. –Unevenly distributed throughout the year.  Likely to be windy.  Experience large daily temperature fluctuations.  Infrequent cloud cover.  Many species, but present in low numbers.

13. Desert Many species exhibit specialized adaptations to climate –Ability to conserve water.  Human impact on deserts: Historically had little impact Modern technology allows for transport of water that resulted in –Development of cities –Limited agriculture by irrigation.

14. Desert

15. Biomes: Major Types of Terrestrial Climax Communities Biomes of the world

16. Temperate Grassland  Temperate grasslands Also known as prairies or steppes Widely distributed over temperate parts of the world.  Receive 25-75 cm of annual precipitation.  Fire is an important force Prevents invasion of trees Releases nutrients from dead plants to the soil.

17. Temperate Grassland  Primary consumers Large herds of migratory grazing mammals Many insect species also common.  Human impact on grassland: Most moist grasslands of world have been converted to agriculture Most drier grasslands have been converted to raising domesticated grazers –Sheep, cattle, and goats.

18. Temperate Grassland Little undisturbed grassland is left –Remaining fragments need to be preserved –Refuges for species that once occupied huge portions of the globe.

19. Temperate Grassland

20. Biomes: Major Types of Terrestrial Climax Communities Biomes of the world

21. Savanna  Savannas are found in tropical parts of Africa, South America, and Australia.  They are characterized by extensive grasslands spotted with occasional patches of trees.  They receive 50-150 cm annual precipitation, unevenly distributed throughout year.  Rainfall patterns produce a seasonally structured ecosystem.  Fire is a common feature.  Many trees are involved in nitrogen fixation.

22. Savanna  Human impact: Savannas have been heavily impacted by agriculture. Because of long periods of drought, raising crops is difficult without irrigation. Some areas support nomadic herding. In Africa, there are extensive areas set aside as parks and natural areas and ecotourism is an important source of income.

23. Savanna

24. Biomes: Major Types of Terrestrial Climax Communities Biomes of the world

25. Mediterranean Shrublands (Chaparral)  Mediterranean shrub lands are located near oceans and are dominated by shrubby plants.  Their climate features wet, cool winters and hot, dry summers.  They receive 40-100 cm annual precipitation.  This biome is typical of the Mediterranean coast, coastal southern California, as well as parts of Africa, Chile, and Australia.  Vegetation is dominated by woody shrubs adapted to hot, dry summers.  Fire is a common feature.

26. Mediterranean Shrublands (Chaparral)  Human impact: Very little undisturbed Mediterranean shrubland still exists. Agriculture is common, often with the aid of irrigation. Major cities are located in this biome.

27. Mediterranean Shrubland (Chaparral)

28. Biomes: Major Types of Terrestrial Climax Communities Biomes of the world

29. Tropical Dry Forest  The tropical dry forest is another biome heavily influenced by seasonal rainfall. These biomes are found in Central and South America, Australia, Africa, and Asia.  Annual precipitation ranges from 50-200 cm.  Many exhibit a monsoon climate with highly seasonal rainfall.  Plants have developed special adaptations to survive drought.

30. Tropical Dry Forest  Human impact: Many of these forests occur in areas of very high human population. Harvesting of wood for fuel and building materials has heavily affected these forests. Many of the forests have been converted to farming or the grazing of animals.

31. Tropical Dry Forest

32. Biomes: Major Types of Terrestrial Climax Communities Biomes of the world

33. Tropical Rainforest  Tropical rainforests are located near the equator where temperature is relatively warm and constant.  Most areas receive 200+ cm annual rainfall, and some receive in excess of 500 cm.  The soil allows high levels of leaching, thus most nutrients are tied up in biomass.  Tropical rainforests have a multi-layered canopy. Epiphytic plants  They also host a very high diversity of species.

34. Tropical Rainforest  Human impact Tropical rainforests are under intense pressure from logging and agriculture. Many of the countries where tropical rainforests occur are poor and seek to obtain jobs and money by exploiting this resource. Forestry can be a sustainable activity, but in many cases it is not.

35. Tropical Rainforest

36. Biomes: Major Types of Terrestrial Climax Communities Biomes of the world

37. Temperate Deciduous Forest  Temperate deciduous forests are typical of the eastern half of the United States, south-central and southeastern Canada, southern Africa, and many parts of Europe and Asia.  These areas receive 75-100 cm annual precipitation, evenly distributed throughout the year.  Trees typically lose their leaves during the winter and replace them the following spring.

38. Temperate Deciduous Forest  This biome features mild winters and a long growing season (6 months).  In contrast to tropical rainforests, where individuals of a tree species are scattered throughout the forest, temperate deciduous forests have many fewer species; some may have two or three dominant tree species.

39. Temperate Deciduous Forest  Human impact: Most of the temperate deciduous forests have been heavily affected by human activity. Much has been cleared for farming. Much of the current forest is subjected to periodic logging. Major population centers of eastern North America and Europe are in areas that were originally temperate deciduous forest.

40. Temperate Deciduous Forest

41. Biomes: Major Types of Terrestrial Climax Communities Biomes of the world

42. Temperate Rainforest  Temperate rainforests exist in coastal areas of northern California, Oregon, Washington, British Columbia, southern Alaska, New Zealand, and the southwest coast of Chile.  West winds bring moist air to the coast. The air is forced over the mountains, cools, and rain or snow is produced.

43. Temperate Rainforest  These forests receive at least 130 cm of rain a year, many receive 300 cm or more.  The cool climate slows evaporation, things are generally damp.  Fertile soil, mild temperatures, and water result in a lush growth of plants.

44. Temperate Rainforest  Sitka spruce, Douglas fir, and western hemlock are typical evergreen coniferous trees.  Old growth forests have trees 800 years old.  Deciduous alder, maple, and cotton wood occur in open areas with enough light.  All trees are covered with mosses, ferns, and other plants that grow on the surface of trees.  Dead trees fall to the ground and rot, providing a site for new tree growth. Dead trees are called nurse trees.

45. Temperate Rainforest  Insects, as well as insect and fruit eating birds such as woodpeckers, chickadees, juncos, and warblers are common.  Slugs are common on the forest floor.  Elk, black tail deer, bears, beavers, and owls are common.  Several species of salmon migrate seasonally up the streams and rivers to spawn.

46. Temperate Rainforest  Human Impact Because of the rich resource of trees, at least half of the original temperate rainforest has been logged. Many remaining forests are scheduled to be logged. Some patches have been protected because they are home to endangered northern spotted owls and the marbled murrelet, a seabird.

47. Temperate Rainforest

48. Biomes: Major Types of Terrestrial Climax Communities Biomes of the world

49. Taiga, Northern Coniferous Forest, or Boreal Forest  Throughout the southern half of Canada, parts of northern Europe, and much of Russia, there is an evergreen coniferous forest known as the taiga, northern coniferous forest, or boreal forest.  This biome receives 25-100 cm precipitation annually.

50. Taiga, Northern Coniferous Forest, or Boreal Forest  It features short, cool summers and long winters with abundant snowfall.  The climate is humid because of the great deal of spring snowmelt; low temperatures reduce evaporation.  The trees are adapted to winter conditions: Needle-shaped leaves prevent water loss. Flexible branches

51. Taiga, Northern Coniferous Forest, or Boreal Forest  Human impact: Human impact is less severe than with many other biomes because population density is low. Logging is common. Herding of reindeer occurs in northern Scandinavia.

52. Taiga, Northern Coniferous Forest, or Boreal Forest

53. Biomes: Major Types of Terrestrial Climax Communities Biomes of the world

54. Tundra  North of the taiga is the tundra, an extremely cold region that lacks trees and has a permanently frozen subsurface soil.  The permanently frozen soil layer is called permafrost.  The tundra receives less than 25 cm annual precipitation.

55. Tundra  This biome has a short, wet summer.  Waterlogged soils and shallow ponds and pools are present in spring and summer.  Plants are usually less than 20 cm tall.  Tundra like communities known as alpine tundra are found on mountaintops throughout the world.

56. Tundra  Human impact: Few people live in this region. Local native people often rely on subsistence hunting for food. Because of the very short growing season, damage to this kind of ecosystem is slow to heal, so the land must be handled with great care.

57. Tundra

58. Biomes: Major Types of Terrestrial Climax Communities Biomes of the world

59. Major Aquatic Ecosystems  Aquatic ecosystems are shaped by key environmental factors: The ability of the sun’s rays to penetrate the water Depth of the water The nature of the bottom substrate The water temperature The amount of dissolved salts

60. Major Aquatic Ecosystems  Aquatic ecosystems with little dissolved salt are called freshwater ecosystems.  Marine ecosystems have a high dissolved salt content.

61. Marine Ecosystems  The pelagic region is the open sea above the sea floor.  The euphotic zone is the upper layer of ocean where the sun’s rays penetrate.  Phytoplankton are microscopic plants floating in the ocean (perform photosynthesis).  Zooplankton are microscopic animals of many kinds that feed on phytoplankton.  Productive aquatic ecosystems contain a plentiful supply of essential nutrients.

62. Marine Ecosystems

63.  Benthic marine ecosystems Benthic organisms, attached or non-attached, live on the ocean bottom. Substrate and temperature are very important characteristics in determining benthic community development. An abyssal ecosystem is a benthic ecosystem that occurs at great depths in the ocean. –There is no light to support photosynthesis. –Animals are scavengers; many are small and generate light for finding or attracting food.

64. Marine Ecosystems  The substrate is important in determining the kind of benthic community that develops. Large plants and algae cannot become established in shifting sand substrate. Mud usually contains little oxygen but is a good substrate for some kinds of rooted plants. Rocky surfaces in the ocean provide a good substrate for many kinds of algae. –A profuse growth of algae is associated with a large variety of animals.

65. Marine Ecosystems  Coral reef ecosystems are composed primarily of coral animals that build cup-shaped external skeletons.  Corals contain single-celled algae and carry on photosynthesis.  They require warm water, thus are found only near the equator.  Most require clear, shallow water with ample sunlight penetration.

66. Marine Ecosystems Coral reef.

67. Marine Ecosystems  Mangrove swamp ecosystems are tropical forest ecosystems that occupy shallow water near the shore and adjacent land.  Their trees tolerate high salt content and excrete salt from their leaves.  They have extensively developed roots that can extend above water.  The trees trap sediment in shallow areas, which results in the development of terrestrial ecosystems.

68. Marine Ecosystems Mangrove swamp

69. Marine Ecosystems  Estuaries consist of shallow, partially enclosed areas where freshwater enters the ocean.  Organisms are specially adapted to varying levels of salinity from tides and river flow.  Estuaries are extremely productive ecosystems because areas are shallow, warm, and nutrient- rich.  These areas are important nursery sites for fish and crustaceans.

70. Marine Ecosystems  Human impact: Oceans cover about 70% of the Earth’s surface. Overfishing has destroyed many of the traditional fishing industries of the world. Fish farming results in the addition of nutrients and has caused diseases to spread from farmed fish to wild fish. Estuaries are affected by fertilizers, animal wastes, and pesticides that flow down rivers from farmland. Use of the oceans as transportation results in oil pollution and trash floating onto the shore.

71. Freshwater Ecosystems  Freshwater ecosystems may be divided into two broad categories: Stationary water (lakes, ponds, and reservoirs) Running water (streams and rivers)

72. Freshwater Ecosystems  Lakes and Ponds The littoral zone of a lake is the region of a lake with rooted vegetation. –Emergent plants have leaves that float on, or protrude above, the water’s surface. –Submerged plants stay submerged below the water’s surface. The limnetic zone is the region of lake with no rooted vegetation.

73. Freshwater Ecosystems Lake ecosystem

74. Freshwater Ecosystems  The productivity of a lake is determined by many factors. Cold temperature reduces rate of photosynthesis. Shallow water allows more photosynthesis. Erosion from land increases nutrient levels. Dissolved oxygen, input via wave action and photosynthesis from aquatic plants, determines the kinds of organisms that can inhabit the lake.

75. Freshwater Ecosystems  Lakes and Ponds Oligotrophic lakes are deep, cold, nutrient-poor. Eutrophic lakes are shallow, warm, nutrient-rich. Biochemical oxygen demand (BOD) is the amount of oxygen used by decomposers to break down a specific amount of organic matter.

76. Freshwater Ecosystems  Streams and Rivers Even though most streams are shallow, it is difficult for most photosynthetic organisms to accumulate nutrients necessary for growth. –Most clear streams are not very productive. –Most debris is input from terrestrial sources. Periphyton is the collection of algae, animals, and fungi attached to rocks and other objects on the bottom.

77. Freshwater Ecosystems  Streams and Rivers Swamps are wetlands containing trees able to live in environments that are permanently flooded, or flooded most of the year. Marshes are wetlands dominated by grasses and reeds. Many swamps and marshes are successional states that eventually become totally terrestrial communities.

78. Freshwater Ecosystems  Human impact: Most freshwater ecosystems have been heavily affected by human activity. Any activity that takes place on land ultimately affects freshwater because of runoff from the land. Agricultural runoff, sewage, sediment, and trash all find their way into streams and lakes.

79. Summary  Ecosystems change as one kind of organism replaces another in a process called succession.  The climax community is a relatively stable stage.  Major regional terrestrial climax communities are called biomes.  Primary determiners of the kinds of biomes that develop are temperature and yearly rainfall distribution.

80. Summary  Major biomes are desert, grassland, savanna, Mediterranean shrublands, tropical dry forest, tropical rainforest, temperate deciduous forest, taiga, and tundra.  Aquatic ecosystems can be divided into marine (saltwater) and freshwater ecosystems.  The shore substrate determines the mixture of organisms that can live there.  Lakes have a structure similar to that of the ocean, but with different species.