THE DISTRIBUTION OFTHE DISTRIBUTION OF
COMMUNITIESCOMMUNITIES
Biogeographic PerspectivesBiogeographic Perspectives
• Ecological Communities - complex
associations of species
• To what ...
Biogeographic PerspectivesBiogeographic Perspectives
• Life zones, Ecoregions or Biomes -
specific kinds of animals and
mi...
Communities and EcosystemsCommunities and Ecosystems
• Definitions –
– Community
– Community structure
– Community functio...
Communities and EcosystemsCommunities and Ecosystems
• Definitions -
• Community -consists of those species
that live toge...
Communities and EcosystemsCommunities and Ecosystems
• Community structure - static properties
including diversity, compos...
Communities and EcosystemsCommunities and Ecosystems
• Community function - all the dynamic
properties and activities that...
Communities and EcosystemsCommunities and Ecosystems
• Ecosystem - includes all the species
inhabiting a place as well as ...
Communities and EcosystemsCommunities and Ecosystems
• Microcosms - small, relatively self-
contained ecosystems
Communities and EcosystemsCommunities and Ecosystems
• Biosphere - largest and only complete
ecosystem -> encompasses the ...
Community Organization :Community Organization :
Energetic ConsiderationsEnergetic Considerations
• Basal metabolic rate -...
Community Organization :Community Organization :
Energetic ConsiderationsEnergetic Considerations
• Body mass - most impor...
Community Organization :Community Organization :
Energetic ConsiderationsEnergetic Considerations
• Larger animals have gr...
Community Organization :Community Organization :
Energetic ConsiderationsEnergetic Considerations
• Smaller organisms requ...
Community Organization :Community Organization :
Energetic ConsiderationsEnergetic Considerations
• Any geographic area co...
Community Organization :Community Organization :
Energetic ConsiderationsEnergetic Considerations
• Trophic Status - influ...
Community Organization :Community Organization :
Energetic ConsiderationsEnergetic Considerations
• Ecological Pyramids - ...
Community Organization :Community Organization :
Energetic ConsiderationsEnergetic Considerations
• Carrying Capacity - (m...
Community Organization :Community Organization :
Energetic ConsiderationsEnergetic Considerations
• Carrying Capacity - (m...
Community Organization :Community Organization :
Energetic ConsiderationsEnergetic Considerations
• Carrying Capacity - (m...
Community Organization :Community Organization :
Energetic ConsiderationsEnergetic Considerations
• Carrying Capacity - (m...
Community Organization :Community Organization :
Energetic ConsiderationsEnergetic Considerations
• Carrying Capacity - (m...
Community Organization :Community Organization :
Energetic ConsiderationsEnergetic Considerations
• Carrying Capacity - (m...
Community Organization :Community Organization :
Energetic ConsiderationsEnergetic Considerations
• Carrying Capacity - (m...
Community Organization :Community Organization :
Energetic ConsiderationsEnergetic Considerations
• Productivity varies gr...
Terrestrial BiomesTerrestrial Biomes
• Terrestrial communities are classified on
the basis of the structure of the vegetat...
Terrestrial BiomesTerrestrial Biomes
• Observed that similar climate regimes do tend to support
• structurally and functio...
Terrestrial BiomesTerrestrial Biomes
• Six major forms of terrestrial vegetation
recognized:
• 1.) Forest
• 2.) Woodland
•...
Terrestrial BiomesTerrestrial Biomes
• 1.) Forest - a tree-dominated assemblage
with a fairly continuous canopy
Terrestrial BiomesTerrestrial Biomes
• 2.) Woodland - a tree-dominated
assemblage in which individuals are
widely spaced, ...
Terrestrial BiomesTerrestrial Biomes
• 3.) Shrubland - a fairly continuous layer of
shrubs, up to several meters high
Terrestrial BiomesTerrestrial Biomes
• 4.) Grassland - an assemblage
dominated by grasses and forbes
Terrestrial BiomesTerrestrial Biomes
• 5.) Scrub - a mostly shrubby assemblage
in which individuals are discrete or widely...
Terrestrial BiomesTerrestrial Biomes
• 6.) Desert - an assemblage with very
sparse plant cover in which most of the
ground...
Terrestrial BiomesTerrestrial Biomes
• Twelve common terrestrial biomes are
recognized
– correspond to the distribution of...
Terrestrial BiomesTerrestrial Biomes
• Tropical rain forest - richest and most
productive
• covers approximately 6% of sur...
Terrestrial BiomesTerrestrial Biomes
• Tropical rain forest (continued)–
• dominant plants are large evergreen trees that
...
Tropical rain forestTropical rain forest
Terrestrial BiomesTerrestrial Biomes
• Tropical deciduous forest - occur in hot
lowlands outside the equatorial zone (betw...
Tropical deciduous forestTropical deciduous forest
Synchronous blooming at the
start of the dry season
Madagascar
Puerto R...
Terrestrial BiomesTerrestrial Biomes
• Thorn woodland - tropical and subtropical
• hot semiarid lowlands
• small spiny or ...
Terrestrial BiomesTerrestrial Biomes
• Tropical savanna - dominated by a nearly
continuous layer of xerophytic grasses and...
Terrestrial BiomesTerrestrial Biomes
• Tropical savanna (continued) -
• annual rainfall varies from 30 to 160 cm
• 3 commo...
Tropical SavannaTropical Savanna
Africa
Australia
Terrestrial BiomesTerrestrial Biomes
• Desert - hot deserts and semideserts
occur around the world at low to
intermediate ...
DesertDesert
Terrestrial BiomesTerrestrial Biomes
• Sclerophyllous woodland (and
Chaparral) - mild temperate climates
• --> moderate wi...
ChaparralChaparral
King Sugar Bush
Californis Blue Oak, Iron Oak Aardwolf
Terrestrial BiomesTerrestrial Biomes
• Sclerophyllous woodland (continued) -
• --> dominant plants have sclerophyllous
(ha...
Terrestrial BiomesTerrestrial Biomes
• Subtropical evergreen forest - also called
Oak-laurel forests or Montane forests
• ...
Terrestrial BiomesTerrestrial Biomes
• Temperate deciduous forest - temperate
latitudes
• --> also called Summer-green Dec...
Temperate deciduous forestTemperate deciduous forest
Terrestrial BiomesTerrestrial Biomes
• Temperate rain forest - uncommon, found
along the western coast of continents where...
Temperate rain forestTemperate rain forest
Terrestrial BiomesTerrestrial Biomes
• Temperate grassland - situated geographically and
climatically between the deserts ...
Temperate GrasslandTemperate Grassland
Terrestrial BiomesTerrestrial Biomes
• Boreal forests – “swamp forest”, broad
band across northern North America,
Europe, ...
Terrestrial BiomesTerrestrial Biomes
• Boreal forests (continued) -
• --> decomposition rates are slow because of
cool tem...
Boreal forestsBoreal forests
Terrestrial BiomesTerrestrial Biomes
• Tundra - treeless biome found between
the boreal forests and the polar ice caps
• -...
Terrestrial BiomesTerrestrial Biomes
• Tundra (continued) -
• --> single, dense stratum of vegetation
• --> high productiv...
TundraTundra
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Biogeo lec 5 the distribution of communities

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Biogeo lec 5 the distribution of communities

  1. 1. THE DISTRIBUTION OFTHE DISTRIBUTION OF COMMUNITIESCOMMUNITIES
  2. 2. Biogeographic PerspectivesBiogeographic Perspectives • Ecological Communities - complex associations of species • To what extent are species distributed together as interdependent communities as opposed to being distributed essentially independently of one another?
  3. 3. Biogeographic PerspectivesBiogeographic Perspectives • Life zones, Ecoregions or Biomes - specific kinds of animals and microorganisms are associated with specific vegetation formations associated with particular climates
  4. 4. Communities and EcosystemsCommunities and Ecosystems • Definitions – – Community – Community structure – Community function – Ecosystem – Microcosm – Biosphere
  5. 5. Communities and EcosystemsCommunities and Ecosystems • Definitions - • Community -consists of those species that live together in the same place
  6. 6. Communities and EcosystemsCommunities and Ecosystems • Community structure - static properties including diversity, composition, and biomass of species in a community
  7. 7. Communities and EcosystemsCommunities and Ecosystems • Community function - all the dynamic properties and activities that affect energy flow and nutrient cycling
  8. 8. Communities and EcosystemsCommunities and Ecosystems • Ecosystem - includes all the species inhabiting a place as well as all the physical features of the physical environment
  9. 9. Communities and EcosystemsCommunities and Ecosystems • Microcosms - small, relatively self- contained ecosystems
  10. 10. Communities and EcosystemsCommunities and Ecosystems • Biosphere - largest and only complete ecosystem -> encompasses the entire earth
  11. 11. Community Organization :Community Organization : Energetic ConsiderationsEnergetic Considerations • Basal metabolic rate - varies with body mass
  12. 12. Community Organization :Community Organization : Energetic ConsiderationsEnergetic Considerations • Body mass - most important variable to measure –> larger the organism the more energy it requires for maintenance, growth and reproduction
  13. 13. Community Organization :Community Organization : Energetic ConsiderationsEnergetic Considerations • Larger animals have greater reserves and therefore greater potential to withstand prolonged stresses such as starvation, dehydration, and subfreezing temperatures
  14. 14. Community Organization :Community Organization : Energetic ConsiderationsEnergetic Considerations • Smaller organisms require fewer resources per individual than large ones, use smaller areas, can be more specialized, and still maintain population densities high enough to avoid extinction
  15. 15. Community Organization :Community Organization : Energetic ConsiderationsEnergetic Considerations • Any geographic area contains a greater number of small-bodied species than large ones AND • Large organisms are constrained to have broad geographic ranges
  16. 16. Community Organization :Community Organization : Energetic ConsiderationsEnergetic Considerations • Trophic Status - influences role in the community structure
  17. 17. Community Organization :Community Organization : Energetic ConsiderationsEnergetic Considerations • Ecological Pyramids - successively higher trophic levels tend to have less than 10% the rate of energy uptake of the level below them, and usually contain proportionately lower biomass and fewer individuals and species
  18. 18. Community Organization :Community Organization : Energetic ConsiderationsEnergetic Considerations • Carrying Capacity - (measured in units of usable energy)
  19. 19. Community Organization :Community Organization : Energetic ConsiderationsEnergetic Considerations • Carrying Capacity - (measured in units of usable energy) • –> lower for successively higher levels
  20. 20. Community Organization :Community Organization : Energetic ConsiderationsEnergetic Considerations • Carrying Capacity - (measured in units of usable energy) • –> lower for successively higher levels • –> predictable characteristics that affect ecological roles and geographic distributions
  21. 21. Community Organization :Community Organization : Energetic ConsiderationsEnergetic Considerations • Carrying Capacity - (measured in units of usable energy) • –> lower for successively higher levels • –> predictable characteristics that affect ecological roles and geographic distributions • –> fewer species of carnivores than herbivores
  22. 22. Community Organization :Community Organization : Energetic ConsiderationsEnergetic Considerations • Carrying Capacity - (measured in units of usable energy) • –> lower for successively higher levels • –> predictable characteristics that affect ecological roles • and geographic distributions • –> fewer species of carnivores than herbivores • –> tend to feed on several species
  23. 23. Community Organization :Community Organization : Energetic ConsiderationsEnergetic Considerations • Carrying Capacity - (measured in units of usable energy) • –> lower for successively higher levels • –> predictable characteristics that affect ecological roles • and geographic distributions • –> fewer species of carnivores than herbivores • –> tend to feed on several species • –> broad habitat requirements
  24. 24. Community Organization :Community Organization : Energetic ConsiderationsEnergetic Considerations • Carrying Capacity - (measured in units of usable energy) • –> lower for successively higher levels • –> predictable characteristics that affect ecological roles • and geographic distributions • –> fewer species of carnivores than herbivores • –> tend to feed on several species • –> broad habitat requirements • –> wide geographic distributions • (Ex: Mountain lion, Puma concolor)
  25. 25. Community Organization :Community Organization : Energetic ConsiderationsEnergetic Considerations • Productivity varies greatly among different habitats –> widespread highly productive habitats such as rain forests and coral reefs have higher diversity of specialized species –> small, isolated areas (such as small islands) and widespread unproductive habitats (such as boreal forests and tundra) contain fewer specialized species and more generalized species
  26. 26. Terrestrial BiomesTerrestrial Biomes • Terrestrial communities are classified on the basis of the structure of the vegetation
  27. 27. Terrestrial BiomesTerrestrial Biomes • Observed that similar climate regimes do tend to support • structurally and functionally similar vegetation in disjunct • areas throughout the world • –> these similarities may result from convergence • –> unrelated plant species in geographically isolated • regions have evolved similar forms and similar • ecological roles under similar selective pressures
  28. 28. Terrestrial BiomesTerrestrial Biomes • Six major forms of terrestrial vegetation recognized: • 1.) Forest • 2.) Woodland • 3.) Shrubland • 4.) Grassland • 5.) Scrub • 6.) Desert
  29. 29. Terrestrial BiomesTerrestrial Biomes • 1.) Forest - a tree-dominated assemblage with a fairly continuous canopy
  30. 30. Terrestrial BiomesTerrestrial Biomes • 2.) Woodland - a tree-dominated assemblage in which individuals are widely spaced, often with grassy areas or low undergrowth between them bare
  31. 31. Terrestrial BiomesTerrestrial Biomes • 3.) Shrubland - a fairly continuous layer of shrubs, up to several meters high
  32. 32. Terrestrial BiomesTerrestrial Biomes • 4.) Grassland - an assemblage dominated by grasses and forbes
  33. 33. Terrestrial BiomesTerrestrial Biomes • 5.) Scrub - a mostly shrubby assemblage in which individuals are discrete or widely spaced
  34. 34. Terrestrial BiomesTerrestrial Biomes • 6.) Desert - an assemblage with very sparse plant cover in which most of the ground is bare
  35. 35. Terrestrial BiomesTerrestrial Biomes • Twelve common terrestrial biomes are recognized – correspond to the distribution of climatic zones – latitude and elevation reflect influence of local climate and soil type
  36. 36. Terrestrial BiomesTerrestrial Biomes • Tropical rain forest - richest and most productive • covers approximately 6% of surface • approximately 50% of species • low elevations at tropical latitudes (10o N to 10o S) • abundant rainfall (>180 cm annually) • rainfall tends to be seasonal • temperatures nearly uniform year-round (over 18o C)
  37. 37. Terrestrial BiomesTerrestrial Biomes • Tropical rain forest (continued)– • dominant plants are large evergreen trees that form a closed canopy (30 to 50m) • convergent morphology of trees (buttressed bases, straight trunks, broad leaves with smooth edges) • also characterized by lianas (woody vines) and epiphytes (orchids, ferns and New World bromeliads) • very little light reaches the forest floor which is open and devoid of vegetation
  38. 38. Tropical rain forestTropical rain forest
  39. 39. Terrestrial BiomesTerrestrial Biomes • Tropical deciduous forest - occur in hot lowlands outside the equatorial zone (between 10o and 30o latitude) • rainfall is more seasonal • dry season is more pronounced • canopy is low and more open • trees and shrub shed their leaves during the dry season • flowering and fruit maturation occurs during the dry season
  40. 40. Tropical deciduous forestTropical deciduous forest Synchronous blooming at the start of the dry season Madagascar Puerto RicoCeiba trees in Ecuador
  41. 41. Terrestrial BiomesTerrestrial Biomes • Thorn woodland - tropical and subtropical • hot semiarid lowlands • small spiny or thorny shrubs and trees are the dominant form • Members of the genus Acacia are common on all continents • succulents such as cacti (Cataceae) in the New World and convergent forms of Euphorbia (Euphorbiaceae) in Africa are common • often found on drier sites adjacent to tropical deciduous forests
  42. 42. Terrestrial BiomesTerrestrial Biomes • Tropical savanna - dominated by a nearly continuous layer of xerophytic grasses and sedges and scattered with fire-resistant trees and shrubs • low to intermediate elevations at intertropical latitudes (between 25o N and 25o S) • one or two rainy seasons followed by intense droughts • weather patterns driven by seasonal shifts in the Intertropical Convergence Zone
  43. 43. Terrestrial BiomesTerrestrial Biomes • Tropical savanna (continued) - • annual rainfall varies from 30 to 160 cm • 3 common factors: • 1) seasonally intense precipitation • 2) fire during the dry season • 3) migratory or seasonal grazing • intertropical Africa (most extensive savannas) • support the most diverse community of large grazing mammals in the world
  44. 44. Tropical SavannaTropical Savanna Africa Australia
  45. 45. Terrestrial BiomesTerrestrial Biomes • Desert - hot deserts and semideserts occur around the world at low to intermediate elevations • --> especially in belts of dry climates (30o to 40o N and S) • --> rain is seasonal and unpredictable (often less than 25 cm per year) • --> amount of rainfall is less than the evaporative potential
  46. 46. DesertDesert
  47. 47. Terrestrial BiomesTerrestrial Biomes • Sclerophyllous woodland (and Chaparral) - mild temperate climates • --> moderate winter precipitation • --> long, usually hot, dry summers • --> broad variety of xeric woodlands (Ex. - Pinon-juniper, sandhill pine woodlands, pine flatwoods)
  48. 48. ChaparralChaparral King Sugar Bush Californis Blue Oak, Iron Oak Aardwolf
  49. 49. Terrestrial BiomesTerrestrial Biomes • Sclerophyllous woodland (continued) - • --> dominant plants have sclerophyllous (hard, tough, evergreen) leaves • --> can receive up to 100 cm rain per year • --> areas that receive less than 60 cm of rainfall per year have low, shrubby vegetation -> Sclerophyllous scrubland (Chaparral)
  50. 50. Terrestrial BiomesTerrestrial Biomes • Subtropical evergreen forest - also called Oak-laurel forests or Montane forests • --> common in subtropical mountains at intermediate elevations • --> China, Japan, disjunct areas of the Southern Hemisphere and southeastern U.S. • --> most dominant species are dicotyledons with broad, sclerophyllous evergreen leaves (Ex. - laurels, oaks, and magnolias)
  51. 51. Terrestrial BiomesTerrestrial Biomes • Temperate deciduous forest - temperate latitudes • --> also called Summer-green Deciduous Forests • --> variable in their structure and composition across eastern North America, western Europe, and parts of eastern Asia
  52. 52. Temperate deciduous forestTemperate deciduous forest
  53. 53. Terrestrial BiomesTerrestrial Biomes • Temperate rain forest - uncommon, found along the western coast of continents where precipitation exceeds 150 cm per year and falls during 10 months of the year • --> cool temperatures predominate year round • --> always above freezing • --> epiphyte diversity is high consisting of mosses, lichens, epiphyllous fungus and some ferns • --> renowned for world’s oldest and largest trees
  54. 54. Temperate rain forestTemperate rain forest
  55. 55. Terrestrial BiomesTerrestrial Biomes • Temperate grassland - situated geographically and climatically between the deserts and the temperate forests • --> most extensive in the interior plains of the Northern Hemisphere • --> markedly seasonal, substantial annual variation in temperature and rainfall • --> vegetation dominated by grasses, sedges, and other herbaceous plants (single stratum) • --> tall grasslands to shortgrass plains • --> vegetation growth is stimulated by fire and grazing
  56. 56. Temperate GrasslandTemperate Grassland
  57. 57. Terrestrial BiomesTerrestrial Biomes • Boreal forests – “swamp forest”, broad band across northern North America, Europe, and Asia in regions of cold temperatures • --> extends southward into temperate latitudes at high elevations (i.e., into southern Mexico) • --> dominated by a few species of coniferous trees (Ex. - spruce and firs)
  58. 58. Terrestrial BiomesTerrestrial Biomes • Boreal forests (continued) - • --> decomposition rates are slow because of cool temperatures and waterlogged soils • --> results in the accumulation of peat and humic acids • --> soil nutrients unavailable for plant growth • --> acidic soils and cool temperatures limit diversity and productivity
  59. 59. Boreal forestsBoreal forests
  60. 60. Terrestrial BiomesTerrestrial Biomes • Tundra - treeless biome found between the boreal forests and the polar ice caps • --> also at high elevations on tall mountains (Alpine tundra) • --> temperatures below freezing for at least 7 months of the year • --> precipitation less than many deserts • --> soils more nutrient poor than boreal forests environment
  61. 61. Terrestrial BiomesTerrestrial Biomes • Tundra (continued) - • --> single, dense stratum of vegetation • --> high productivity during short growing season • --> heavily grazed by migratory mammals such caribou (Rangifer tarandius), muskox (Ovibus moshatus) and Dall sheep (Ovis dalli) • --> fragile environment
  62. 62. TundraTundra

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