NAU Lecture 4 on Plant and animal abodes

1. Environmental Science
A Study of Interrelationships
Thirteenth Edition
Enger & Smith
Chapter 6
Kinds of Ecosystems and Communities
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

2. Kinds of Ecosystems and Communities

3. 6.1 Succession
 Succession is a series of regular, predictable
changes in community structure over time.
• Activities of organisms change their surroundings
• Make the environment suitable for other kinds of
organisms.

4. 6.1 Succession
 A climax community
• relatively stable, long-lasting community that is the
result of succession.
• Traditionally, kind of climax community determined by
climate.

5. 6.1 Succession
 Primary succession begins with a total lack of
organisms and bare mineral surfaces or water.

6. 6.1 Succession
 Secondary succession begins with the
disturbance of an existing ecosystem.
• It is much more commonly observed
• generally proceeds more rapidly than primary
succession.

7. Terrestrial Primary Succession
 1. Pioneer stages
 2. Intermediate stages
 3. Climax community

8. Pioneer Stage
• A pioneer community is a
collection of organisms
able to colonize bare rock
(e.g., lichens).
– Lichens help break down rock
and accumulate debris,
helping to form a thin soil
layer.
– The soil layer begins to
support small forms of life.

9. Intermediate Stage
 Lichen community replaced by annual plants.
 Annuals replaced by perennial community
(grasses).
 Perennial community replaced by shrubs.
 Shrubs replaced by shade-intolerant trees.
 Shade-intolerant trees replaced by shade-tolerant
trees.

10. Climax community
 Stable, complex, climax community eventually
reached.
 Process of succession can stop at any point
 The general trend in succession is toward
increasing complexity and more efficient use of
matter and energy.

11. Primary Succession
Primary succession on land

12. Primary Succession
Primary succession from a pond to a wet meadow.

13. Secondary Succession
 Secondary succession
• when an existing community is disturbed or destroyed
but much of the soil and some of the organisms remain.
• Because the soil and nutrients remain, this process can
advance more rapidly than primary succession.
• Plants and organisms that survive, grow quickly and
reestablish themselves.

14. Secondary Succession
• Nearby undamaged communities can serve as
sources of seeds and animals.
• The new climax community is likely to resemble the
destroyed community.

15. Secondary Succession
Secondary succession on land

16. Modern Concepts of
Succession and Climax
 As settlers changed “original” ecosystems to
agriculture, climax communities were destroyed.
• Many farms were abandoned, and land began to
return to its “original” condition.
 Ecologists began to recognize there was not a
fixed, pre-determined community for each part of
the world.
• The only thing differentiating a climax community from
any other successional community is its time scale.

17. Discussion
 http://www.youtube.com/watch?v=AQQupOYonRo

18. 6.2 Biomes Are Determined by Climate
 Biomes are terrestrial climax communities with
wide geographic distributions.
• Determination of a biome
– climate

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

20. Biomes: Major Types of
Terrestrial Climax Communities
 Primary non-biological factors that impact the
kinds of climax communities:
• Temperature
• Patterns of precipitation
– Total
– Form
– Seasonal distribution

22. The Effect of Elevation
on Climate and Vegetation
• Temperature is warmest near the equator and cooler
toward the poles.
• As altitude increases, average temperature
decreases.

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

24. 6.3 Major Biomes of the World:
Desert
 Deserts
• less than 25 cm annual precipitation.
• Unevenly distributed throughout the year.
 Windy
 Large daily temperature fluctuations.
 There are many species, but they are present in
low numbers.
 Many species exhibit specialized adaptations to
climate
• ability to conserve water.

25. Desert

26. Temperate Grassland
 Temperate grasslands, also known as prairies or
steppes
• 25-75 cm of annual precipitation.
• Fire is an important force in preventing the invasion of
trees
• releasing nutrients from dead plants to the soil
 Grasses 60-90% of vegetation
 The primary consumers are large herds of
migratory grazing mammals.
– Many insect species are also common.

27. Temperate Grassland
 Human impact on grassland:
• Most of the moist grasslands of the world have been
converted to agriculture.
• Most of the drier grasslands have been converted to
the raising of domesticated grazers
– sheep, cattle, and goats.
• Little undisturbed grassland is left
– fragments that remain need to be preserved as refuges
for the grassland species

28. Temperate Grassland

29. Savanna
 Savannas
• tropical parts of Africa, South America, and Australia.
 Extensive grasslands spotted with occasional
patches of trees.
 They receive 50-150 cm annual precipitation,
unevenly distributed throughout year.
 Predominant Mammals
• Grazers
 Fire is a common feature.

30. Savanna
 Human impact:
• Savannas have been heavily impacted by agriculture.
– Farming
– Livestock in drier areas
• In Africa, there are extensive areas set aside as parks
and natural areas
– ecotourism is an important source of income.

31. Savanna

32. Mediterranean Shrublands (Chaparral)
 Mediterranean shrublands
• located near oceans and are dominated by shrubby
plants.
 Their climate features wet, cool winters and hot,
dry summers.
• 40-100 cm annual precipitation.
• Fire common feature
 Vegetation is dominated by woody shrubs
adapted to hot, dry summers.
 Insects, birds, reptiles, mammals

33. 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.

34. Mediterranean Shrubland (Chaparral)

35. Tropical Dry Forest
 The tropical dry forest
• heavily influenced by seasonal rainfall.
• Annual precipitation ranges from 50-200 cm.
 Many exhibit a monsoon climate with highly
seasonal rainfall.
 Plants have developed special adaptations to
survive drought.

36. Tropical Dry Forest
 Human impact:
• Many of these forests occur in areas of very high
human population. (India)
• 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.

37. Tropical Dry Forest

38. Tropical Rainforest
 Tropical rainforests
• located near the equator where temperature is relatively
warm and constant.
– 200+ cm annual rainfall, and some receive in excess of 500
cm.
 Tropical rainforests have a multi-layered canopy.
 They also host a very high diversity of species.
• More species in tropical rainforests than in the rest of the
world

39. 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.

40. Tropical Rainforest

41. Temperate Deciduous Forest
 Temperate deciduous forests
• 75-100 cm annual precipitation, evenly distributed
throughout the year.
• Mild winters and a long growing season (6 months).
 Trees typically lose their leaves during the winter
and replace them the following spring.
• Specific species: maples, birch, oaks
 Insects, migrant birds, small mammals, and
foxes, coyotes

42. Temperate Deciduous Forest
 Human impact:
• 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.

43. Temperate Deciduous Forest

44. Temperate Rainforest
 West winds bring moist air to the coast.
• air is forced over the mountains, cools, and rain or
snow is produced.
• at least 130 cm of rain a year, many receive 300 cm
 The cool climate slows evaporation, things are
generally damp.
• All trees are covered with mosses, ferns
 Lush growth of plants
• Sitka spruce, Douglas fir
• Old growth forests have trees 800 years old.

45. Temperate Rainforest
 Insects, as well as insect and fruit eating birds
 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.
• Some patches have been protected because they are
home to endangered northern spotted owls and the
marbled murrelet, a seabird.

47. Temperate Rainforest

48. Northern Coniferous Forest,
or Boreal Forest
 An evergreen coniferous forest known as the
northern coniferous forest, or boreal forest.
• 25-100 cm precipitation annually.
 It features short, cool summers and long winters
with abundant snowfall.
• The climate is humid because of the great deal of
spring snowmelt
 The trees are adapted to winter conditions:
• Needle-shaped leaves prevent water loss.
• Flexible branches

49. Northern Coniferous Forest,
or Boreal Forest
 Birds are migratory
 Mammals: deer, moose, wolves, mice,
snowshoe hares

50. Taiga, Northern Coniferous Forest,
or Boreal Forest

51. Tundra
 North of the taiga is the tundra,
• an extremely cold region that lacks trees and has a
permanently frozen subsurface soil.
 The tundra receives less than 25 cm annual
precipitation.
• short, wet summer.
 Plants are usually less than 20 cm tall.
• Grasses and lichens
 Insects, waterfowl, Caribou, artic foxes

52. Tundra
 Human impact:
• 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.

53. Tundra

54. Grassland vs Savanna
 Similarities:
•
•
•
•
Fire
Predominant plant: grasses
Primary consumers: grazers
Both have been impacted by agriculture
 Differences:
• Precipitation: 25-75 cm in grassland; 50-150 in
savanna
• Savanna: heavy rainfall followed by drought

55. Tundra vs Desert
 Similarities:
• 25 cm annual precipitation
• Windy
• Few people occupy
 Differences:
• Temperature
• Type of plants and animals

56. 6.4 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
– Marine ecosystems have a high dissolved salt content.

57. Marine Ecosystems
 Estuaries consist of shallow, partially enclosed
areas where freshwater enters the ocean.
• “Where the rivers meet the sea”
 Organisms are specially adapted to varying
levels of salinity from tides and river flow.
 Extremely productive ecosystems because
areas are shallow, warm, and nutrient-rich.
• important nursery sites for fish and crustaceans.

59. Estuaries
Human impact:
Estuaries are affected
by:
fertilizers
animal wastes
pesticides
sewage
Settlements
housing
marinas

60. Freshwater Ecosystems
 Freshwater ecosystems may be divided into two
broad categories:
• Stationary water (lakes, ponds, and reservoirs)
• Running water (streams and rivers)
 Human impacts
 Agricultural runoff, sewage, sediment, and trash all find
their way into streams and lakes.

61. Freshwater Ecosystems
Lake ecosystem

62. APA style citations
 https://owl.english.purdue.edu/owl/resource/560/02/
 https://owl.english.purdue.edu/owl/resource/560/03/
 https://owl.english.purdue.edu/owl/resource/560/06/
 https://owl.english.purdue.edu/owl/resource/560/10/

63. 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.

64. Summary
 Major biomes are desert, temperate grassland,
savanna, Mediterranean shrublands, tropical dry
forest, tropical rainforest, temperate deciduous
forest, temperate rain 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.