1. BIOL 4120: Principles of Ecology Lecture 5: Biome Concept in Ecology
Dafeng Hui
Room: Harned Hall 320
Phone:
Biogeography is the study of the spatial or geographical distribution of organisms (both present and past).
Biogeographical ecology: study spatial and geographical distribution of organisms and climate. The goal is to describe and understand the processes responsible for the many Patterns in the distribution of species and larger taxonomic groups.
This chapter, we will focus on terrestrial ecosystems.
We will only look at the large-scale distribution of biomes in terrestrial ecosystems.

2. Topics
5.1 Climate is the major determinant of plant growth form and distribution
5.2 Climate determine the boundaries of terrestrial biomes
5.3 Walter climate diagrams distinguish the major climate biomes
5.4 Temperate climate zones have average annual temperature between 5 and 20oC
5. 5 Boreal and polar climate zones have average temperatures below 5oC
5. 6 Climate zones with tropical latitudes have average temperatures exceeding 20oC
5.7 Biome concept must be modified for freshwater aquatic systems
5.8 Marine aquatic systems are classified principally by water depth

3. Biomes are classified according to the predominat plant types and climate

4. Concept of Biomes:
F.E. Clements and V.E. Shelford, 1939
Combining broad-scale distribution of both plants and associated animals into a single classification
Biomes: classified according to the predominant plant types
Campbell 1996: the world's major communities, classified according to the predominant vegetation and characterized by adaptations of organisms to that particular environment.

5. Biomes reflect adaptations of dominant plant life forms
Three general plant forms: trees, shrubs, and grasses.
Why are there consistent patterns in the distribution and abundance of three dominant plant life forms that relate to climate and physical environment?
Adaptation.

6. Biomes reflect adaptations of dominant plant life forms
These three forms represent different patterns of carbon allocation and morphology
Grasses: less C to production of supporting tissue (stem) than do wood plants (shrubs and trees), more to photosynthetic tissues (leaves)
Woody plants: shrubs allocate lower percentage to stem than trees.
Trees: more to stem, advantage of height and access to light, cost more for maintenance and respiration.
As environmental conditions become adverse for photosynthesis (dry, low nutrient, cold T), trees will decline in both stature and density until they are no longer able to persist as a component of the plant community.
Adaptation.
If you grow them together, which one has advantage in term of light and nutrient uptake

7. Forests
Within broad classes of forest and woodland ecosystem (trees are dominant or co-dominant), leaf form is another plant characteristic.
Based on longevity of leaf
Deciduous (live for only one year or growing season)
Winter-deciduous (temperate regions, low winter T)
Drought-deciduous (subtropical and tropical, leaf shed on dry periods)
Evergreen (live beyond a year)
Broadleaf-evergreen (tropic rainforest, no distinct growing season, year-round photosynthesis)
Needle-leaf evergreen (growing season is short or nutrient availability constrains photosynthesis and plant growth)
Economic model to explain adaptation of leaf form: cost to produce leaf and gain from photosynthesis.
Adaptation.
Production of a leaf has cost to the plant that can be defined in term of carbon and nutrients requirements
The time required to pay back the cost of production (carbon) will be a function of rate of net photosynthesis (carbon gain)
If leaf photosynthetic rate is very low, it may not pay back the cost within one growing season. Plants adapted to this env. Can’t afford a deciduous leaf form  evergreen forest. Distinct growing season, can’t produce enough carbon through photosynthesis

8. Concept of Biomes:
Major terrestrial biome types (eight , nine, and varies):
Tropical forest, temperate forest, conifer forest (taiga and boreal forest), tropical savanna, temperate grasslands, chaparral (shrublands), tundra, and desert.

9. 5.1 Climate is the major determinant of plant growth form and distribution
Since organisms are adapted to the physical environments of their biomes, ranges of species are limited by these physical conditions
In terrestrial environments, temperature and moisture are the most important variables, particularly for plants.
Adaptation.

10. Related species may differ in their ecological tolerances,
4/11/2017
Related species may differ in their ecological tolerances,
and distribute Differently
It’s easy to understand that different species may have quite different distribution ranges.

11. 5.2 Climate defines the boundaries of terrestrial biomes (Walter)
4/11/2017
5.2 Climate defines the boundaries of terrestrial biomes (Walter)
Biomes is defined by the predominant vegetation types and climates.
Climate factors such as temperature and precipitation /soil moisture determine plant growth form and distribution
For climate classfication, the most widely adopted one is the climate zone system developed by the German ecologist Heiinrich Walter.
It has nine major divisions, based on annual cycles of temperature and precipitation.
This classification is first based on climate, with boundaries between climate zones drawn to match changes between major vegation types.

12. Robert Whittaker, Cornell Uni.
Biomes and climate
Boundaries between biomes are broad and often indistinct
Other factors: topography, soils, and exposure to disturbances such as fire
Many classification schemes for biomes exist. Whittaker defined biomes first by their vegetation type, then devised a simple climate diagram on which he plotted the approximately boundaries of his biomes with respect to temperature and precipitation.
On this diagram, most locations on earth fall within a triagular area with three corners represent warm and moist, warm and dry, and cold and dry. (few falls on cold and moist)
Tennessee: t=, PPT=1300 cm
Other factors also help to shape the vegetation type distribution. Climate influence fire  help maintain the grassland; otherwise, trees could grow: one example,l Australian eucalyptus form forests under climate conditions only support grassland on other continents (leave and bark have high oil contents, induce fire to kill other trees seedlings)
The textbook, three regions

13. 4/11/2017
Nashville, TN
Mean temperature: 14.9 oC, annual precipitation: cm
Source: US Climate Data
Temperate seasonal forest

14. Robert Whittaker, Cornell Uni.
Biomes and climate
Boundaries between biomes are broad and often indistinct
Other factors: topography, soils, and exposure to disturbances such as fire
Many classification schemes for biomes exist. Whittaker defined biomes first by their vegetation type, then devised a simple climate diagram on which he plotted the approximately boundaries of his biomes with respect to temperature and precipitation.
On this diagram, most locations on earth fall within a triagular area with three corners represent warm and moist, warm and dry, and cold and dry. (few falls on cold and moist)
Tennessee: t=, PPT=1300 cm
Other factors also help to shape the vegetation type distribution. Climate influence fire  help maintain the grassland; otherwise, trees could grow: one example,l Australian eucalyptus form forests under climate conditions only support grassland on other continents (leave and bark have high oil contents, induce fire to kill other trees seedlings)
The textbook, three regions

15. BIOL 4120: Principles of Ecology Lecture 5: Biome Concept in Ecology
Dafeng Hui
Room: Harned Hall 320
Phone:
Biogeography is the study of the spatial or geographical distribution of organisms (both present and past).
Biogeographical ecology: study spatial and geographical distribution of organisms and climate. The goal is to describe and understand the processes responsible for the many Patterns in the distribution of species and larger taxonomic groups.
This chapter, we will focus on terrestrial ecosystems.
We will only look at the large-scale distribution of biomes in terrestrial ecosystems.

16. Recap
Climate and soil
Soil profile, soil weathering process, soil order
Biomes
Climate is the major determinant of plant growth form and distribution
Climate determine the boundaries of terrestrial biomes

17. 5.3 Walter climate diagrams distinguish the major terrestrial biomes
4/11/2017
5.3 Walter climate diagrams distinguish the major terrestrial biomes
Precipitation and temperature interactively determine biomes
To permit ecologically meaningful comparisons of climates between localities, Walter developed a climate diagram to illustrate seasonal periods of water deficit and abundance.
When P is higher than T, water is plentiful, and plant productition is limited by T
Conversely, when T is higher than P, plant productivity is limited by P. (20 mm precipitation=10oC T, balanced)
Walter’s scales equate 20 mm of monthly PPT with 10oC in temperature

18. Each climate zone has a typical seasonal patterns of T and P.
4/11/2017
Each climate zone has a typical seasonal patterns of T and P.

19. 4/11/2017
World Wildlife Fund (WWF) recognizes 14 biomes. Here nine.

20. 4/11/2017
5.4 Temperate climate zones have average annual temperature between 5 and 20oC
Temperate seasonal forest biome (Climate zone VI)
Temperate rain forest biome (Climate zone V)
Temperate grassland/desert biome (Climate zone VII)
Woodland/shrubland biome (climate zone IV)
Subtropical desert biome (climate zone III)

21. 4/11/2017
Also called deciduous forest
Growing seasona days
P > T
Decidous forests are dominant form, usually have a layer of smaller trees and shrub as understory
In part of this zone, when soil is sandy and nutrient poor, needle-leaf forest such as pine doninants
Fires are frequent, trees are able to resist fire demange.

22. Temperate seasonal forest
Forest ecosystems dominate the wetter regions of the temperate zone
Deciduous forest covered large area of Europe and China, but mostly converted to croplands, only exist in eastern China
North America, deciduous forests consist of a number of associations (next slide)
Southern Hemisphere, temperate evergreen forest become predominant
Asiatic broadleaf forest found in eastern China, Japan, Korea is similar to the North American deciduous forest

23. Large scale distribution of temperate forest in eastern US
Mesophytic forest: Being grow or adapted to moist environment

24. 4/11/2017
Warm temperate climate near Pacific coast; mild winter, heavy winter rains;
Support extremelly tall evergreen forest: 60-70m or even 100m
Compared to tropical forest, few species are supported here.

25. 4/11/2017
Rainfall: 30 to 80 cm, infrequently
Growing seaon: days (north to south)
Also called praries (N.A) and steppes (central Asia)
Grassland soil: rich in organic matter (low acidity, not heavyly leached)
Vegetation: grasses, 2m (tall grass, moister; or 0.2m in more arid regions) and forbs are anundant
Fire: important. Grasses have zhizomes, resist fire and shoots can respount. Or seeds are fire resist.
When P is between 25 and 50cm, desert: west US, Great Basin of west US.
Vegetation: north, Sagebrush; south: juniper and pinon trees
ET>P
Fire: infrequently, low fuel
Overgrazing could convert dry grassland into desert.

26. Grassland ecosystems Rainfall is very important: 250 to 800 mm
Other factors: fire, and human activity (convert grassland to desert by overgrazing)
Area: dropped from 42% to <12% of original size
Location: mid-latitudes in mid-continental regions
Typical: prairies of North America, steppes of central Eurasia

27. Grassland in North America
Tallgrass prairie in Iowa,
mixed-grass prairie;
shortgrass steppe
Tallgrass prairie
Big bluestem, >1m
Mixed-grass prairie
Needlegrass-garma grass
Shortgrass prairie
Blue garma and buffalo grass
Support grazers, herbiviors, canivoirs

28. Aboveground primary productivity is related to MAP (52 grassland)
Figure 23.24
Aboveground primary productivity is related to MAP (52 grassland)
Grasslands are most productive when MAP>800 mm and MAT > 15oC

29. 4/11/2017
5.4 Temperate climate zones have average annual temperature between 5 and 20oC
Temperate seasonal forest biome (Climate zone VI)
Temperate rain forest biome (Climate zone V)
Temperate grassland/desert biome (Climate zone VII)
Woodland/shrubland biome (climate zone IV)
Subtropical desert biome (climate zone III)

30. sclerophyllous: hard-leaved vegetation
4/11/2017
sclerophyllous: hard-leaved vegetation
Special climate zone: only occurs in a few places (five on map),
Mediterranean climate zone: mild winter temperature, winter rain and summer drought
Vegetation: thick evergreen shrubby vegetation (1-3m tall, with deep roots and drought-resistant foliage).
earned name: sclerophyllous: hard-leaved vegetation
Fire: frequent, fire resist
Fynbos is the natural shrubland or heathland vegetation occurring in a small belt of the Western Cape of South Africa, mainly in winter rainfall coastal and mountainous areas with a Mediterranean climate. The Fynbos ecoregion is within the Mediterranean forests, woodlands, and scrub biome.
The word fynbos is the Afrikaans for "fine bush", referring to the thin leaves.

31. 4/11/2017
SaharaSubtropical09,100,000 9,100,000+[3]03,320,000 3,320,000+Algeria, Chad, Egypt, Eritrea, Libya, Mali, Mauritania, Morocco, Niger, Sudan, Tunisia and Western Sahara
Gobi in China

32. Desert Area: 25 to 35% Location: latitudes between 15 and 30o
Cause: Global air mass circulation
T: High in summer, could be cold in winter
PPT: low, <150 mm
Typical examples: majority in Northern Hemisphere, Sahara in Africa, Gobi in Asia, western North America

33. Deserts are not the same everywhere
Cold desert: Great Basin of North America, the Gobi, Takla Makan, and Turkestan deserts of Asia
Species: sagebrush, shadscale, chenopods, etc
Hot desert: Mojave, the Sonoran, and Chihuahuan
Vegetation: none to some combination of chenopods, dwarf-shrubs, and succulents
Figure 23.13

34. Hot desert: a. Chihuahuan Desert, b
Hot desert: a. Chihuahuan Desert, b. Great Victorian Desert in Australia, c. Dunes in Saudi Arabian desert.
Figure 23.14

35. Plants and animals in Desert
Survive of desert plants:
Adapted to scarcity of water, low primary productivity
Flowering only when moisture is present
Fast grow, flower, produce seeds and die
Deep-rooted (mesquite, taproots reach water table)
CAM pathway, special leaf structure
Survive of animals
Support a diversity of animal life (bettles, ants, locusts, lizards, snakes, birds and mammals)
Grazing herbivores: generalists, consume a wide range of species.
Desert carnivores, such as fox and coyotes, have mixed diet include leaves and fruits.

36. 4/11/2017
5. 5 Boreal and polar climate zones have average temperatures below 5oC
Boreal forest biome (Climate zone VIII)
Tundra biome (Climate zone IX)

37. 4/11/2017

38. Black spruce in North America taiga (boreal forest)
Figure 23.26
Some coniferous forest. A. Norway spruce, b. Rocky Mountaine subalpine forest, c. montane coniferous forest in Rocky Mountains

39. 4/11/2017
Du juan hua, in n. temperate region, why tundra?

40. Arctic Tundra Tundra is treeless plain
Arctic tundra is a frozen plain, clothed in sedges, heaths, and willows, dotted with lakes, and crossed by streams
Cold Temperature and low precipitation
Two types:
Polar desert: dry soil, less than 5% plant cover
Wet tundra: up to 100% plant coverage, wet to moist soil
Unique conditions:
permafrost: isolate and protect soil OM
vegetation: simple form, slow growth, allocate more to roots.

41. Arctic tundra
Canada
Figure 23.29

42. Rocky Mountains alpine tundra
Figure 23.31

43. Tropical rain forest biomes (Climate zone I)
4/11/2017
5. 6 Climate zones with tropical latitudes have average temperatures exceeding 20oC
Tropical rain forest biomes (Climate zone I)
Tropical seasonal forest/savanna biome (Climate zone II)

44. 4/11/2017

45. Tropic rain forest
Location: Equatorial zone between latitudes 10 oN and 10 oS
T: warm all year, monthly mean T>20 oC
PPT: Rainfall occurs daily, min. monthly>60mm
Typical example: Amazon basin of South America

46. Recap
Climate zone with temperate climate zones have average temperatures between 5 and 20 oC
Boreal and polar climate zones have average temperatures below 5oC
Climate zones with tropical latitudes have average temperatures exceeding 20oC

47. High net primary productivity (NPP)
Tropic rain forests in Amazon (a), Malaysia (b), and Northeast Australia (c)
High net primary productivity (NPP)
High diversity of plant and animal life
7% land surface, >50% plant and animal species
10-km2 contain 1500 species of flowing plants and 750 tree species.
Richest area in Malaysia, 7900 species
Tree m tall, some 55 m or so

48. 90% of all primate species live in the tropical rain forest
orangutan (an arboreal ape)
Gibbons, langurs, macaques
(Malaysian)
Gorillas, and chimpanzees
(Africa)
Lemurs
Beetles, butterflies

49. Vertical stratification of a tropic rain forest
Figure 23.7
Vertical stratification of a tropic rain forest

50. 4/11/2017
Acacia: he huan.

51. Tropical Savannas
Location: Equatorial zone between latitudes 30oN and 30oS, Dry tropic and subtropical.
T: warm all year, annual mean T>18oC
PPT: distinct seasonality in rainfall, large interannual variation
Typical example: South America

52. Tropical Savannas Savanna: means the treeless areas of South America
Grassland with scattered trees.
Characteristics:
Occur on land surfaces of little relief, often on old plateaus, dissected by rivers, soil poor in nutrients, especially P
Dominant species are fire-adapted, subjected to recurrent fires.
Grass cover with or without wood vegetation is always present
Woody component is short-lived (less than a few decades).
Two-layer vertical structure (ground level grass + shrubs or trees)
Support a large and varies assemblage of herbivores, invertebrate and vertebrate, grazing and browsing.

53. Interaction between annual PPT and soil texture in defining biomes
In clay soil, it requies more precipitation to grow forest (high water holding capacity)
Interaction between annual PPT and soil texture in defining biomes
Access by plants to soil moisture is more limited on the heavy textured soils (clay) than sandy oil.

54. 5.7 Biome concept must be modified for aquatic systems
4/11/2017
5.7 Biome concept must be modified for aquatic systems
Terrestrial biomes: classified by growth form of dominant vegetation reflects climate conditions.
Aquatic biomes: in many aquatic systems, there is no “vegetation” form, only algae
Classified primarily by physical characteristics such as salinity, water movement, and depth
Freshwater aquatic:
Flowing water: Streams and rivers
Standing water: lakes and ponds
Wetlands
Estuaries

55. Flowing water: streams and rivers
4/11/2017
Flowing water: streams and rivers
Lotic systems: flowing fresh waters, such as streams and rivers
Streams form wherever P exceeds ET, and excess water drains from the land.
Riffles: water runs rapidly over a rocky substratum
Pools: deeper stretches of more slowly moving water
Riparian zone: terrestrial veg influenced by seasonal flooding
Allochthonous: organic material that enters the aquatic system from the outside
Autochthonous: home grow its organic material.
Riffle: R e fl
Riparian: r e p ai r e n?
A’loc sir nurse
A’toc sir nurse
Lack richness and diversity

56. Fluvial systems, as rivers are sometimes called
4/11/2017
Fluvial systems, as rivers are sometimes called
Fluvial:

57. Standing water: lakes and ponds
4/11/2017
Standing water: lakes and ponds
Layers of lake:
Littoral zone
Liminetic or pelagic zone
Benthic zone
Liminetic: down to the depth of light penetration.
Pelagic: open ocean area
Lentic system: nonflowing water systems, such as lakes and ponds

58. Wetlands Wetlands: terrestrial and aquatic communities come together
4/11/2017
Wetlands
Wetlands: terrestrial and aquatic communities come together
Lands consisting soil saturated with water and supports vegetation that specifically adapted.
Include swamps, marshes, bogs (fresh water), salt marshes and mangrove (associated with marine environments)
Plants can tolerate low O2
Important habits for a wide variety of animals, waterfowl, fish, invertebrates
Protect coastal areas from ravages of hurricanes
Wetland sediments immobilize potentially toxic or polluting substances dissolved in water and are thus natural water purifying plants.

59. Estuaries Estuaries are found at the mouths of river
4/11/2017
Estuaries
Estuaries are found at the mouths of river
Mix of fresh and salt water
Extremely productivity systems
‘As-tu-ai-rei-s

60. Human inputs into freshwater biomes
4/11/2017
Human inputs into freshwater biomes
Acid rain and eutrophication
1. Acid rain: combustion of fossil fuels, sulfur dioxide, nitrogen oxides
pH<4 in steams and rivers
2. Eutrophication: addition of limiting nutrients, such as N, P to aquatic ecosystems.
runoff: sewage, industrial wastes, fertilizers, animal wastes from agricultural lands.
Oxygen depletion
Dam, wetland, river,

61. 5.8 Marine aquatic systems are classified principally by water depth
4/11/2017
5.8 Marine aquatic systems are classified principally by water depth
Variation in marine environments: temperature, salinity, depth (which influence light and pressure), currents, substrata and at the edges of ocean and tides. Depth: Littoral zone (intertide zone): extends between highest and lowest tidal water levels. Neritic zone: extends to depth of 200m, high productivity. Oceanic zone: below neritic, sparse nutrient, low production.

62. Seafloor below oceanic zone.
4/11/2017
Benthic zone
Seafloor below oceanic zone.
Photic zone:
With sufficient light for photosynthesis
Aphotic zone: no light for photosynthesis
Liminetic

63. Coral reefs: shallow water of warm ocean, T>20oC year around
4/11/2017
Open ocean === desert
But in:
Coral reefs: shallow water of warm ocean, T>20oC year around
very productive and high diverse
Like tropical rain forest in terrestrial biome
Problem: global warming, coral bleaching

64. Thank you!

66. Winter-deciduous
Figure 23.2
Drought-deciduous

67. Broadleaf evergreen in tropic rain forest in Australia
Figure 23.3
Needle-leaf evergreen in Sierra Nevada, US

68. Figure 23.12

69. Figure 23.10

70. Figure 23.22

71. BIOL 4120: Principles of Ecology Lecture 5: Biome Concept in Ecology
Dafeng Hui
Room: Harned Hall 320
Phone:
Biogeography is the study of the spatial or geographical distribution of organisms (both present and past).
Biogeographical ecology: study spatial and geographical distribution of organisms and climate. The goal is to describe and understand the processes responsible for the many Patterns in the distribution of species and larger taxonomic groups.
This chapter, we will focus on terrestrial ecosystems.
We will only look at the large-scale distribution of biomes in terrestrial ecosystems.

72. Recap
Biomes, concept
Climate is the major determinant of plant growth form and distribution
Climate determine the boundaries of terrestrial biomes
Walter climate diagrams distinguish the major climate biomes
Temperate climate zones have average annual temperature between 5 and 20oC