Transcript 第七週

Chapter 7
Physical
Environment
© 2002 by Prentice Hall, Inc.
Upper Saddle River, NJ 07458
Chapt. 07
Outline
• Physical variables commonly
limit the abundance of plants
and animals
– Resources
– Variables critical to survival
• Physical factors commonly
limiting species
#2
Chapt. 07
Outline
• Physical factors commonly
limiting species (cont.)
–
–
–
–
Extreme temperatures
Wind
Salt
Global climate change
#3
Chapt. 07
Outline
• Physical environment limits
abundance and distribution
• Physical environment can alter
species composition
#4
Chapt. 07
Limiting Factors限制因子
• 非生態因子Non-ecological
factors:
– 對有機體生活無明顯影響的環境因子。
• 生態因子Ecological Factors
– 生物性因子Biotic factors
– 非生物性因子 abiotic factors
#5
Chapt. 07
#6
Chapt. 07
#7
Chapt. 07
#8
Chapt. 07
#9
Chapt. 07
#10
Chapt. 07
非生物性因子
光--光質 強度 日照長度
溫度—耐受性（廣溫性，狹溫性）
水—降水量、雪水覆蓋、冰覆蓋、溼度
空氣—氣體種類和分壓
土壤—基底substrate
無機鹽（生物鹽類biogenic salt）
#11
Chapt. 07
非生物性因子與
生物之間的關係-1
光--光質 強度 日照長度 （世界上有沒
有不需要太陽光的生態體系？）
繁殖、遷移、換毛、換羽、體色、視覺和視
覺器官、行為、維生素D合成
#12
Chapt. 07
非生物性因子與
生物之間的關係-2
溫度—耐受性（廣溫性，狹溫性）
水—降水量、雪水覆蓋、冰覆蓋、溼度
滲透壓調節、體液水分吸收、保水構造、
行為（夏眠aestivation、滯育diapause）
空氣—氣體種類和分壓
呼吸和光合作用、循環
土壤—基底substrate
無機鹽（生物鹽類biogenic salt）
#13
Chapt. 07
非生物性因子
光--光質 強度 日照長度
溫度—耐受性（廣溫性，狹溫性）
水—降水量、雪水覆蓋、冰覆蓋、溼度
空氣—氣體種類和分壓
土壤—基底substrate
無機鹽（生物鹽類biogenic salt）
#14
Chapt. 07
Physical Variables
• Temperature
– Affects biological processes
– Organism’s inability to regulate
body temperature
• Distribution of Coral Reefs (Figure
7.3)
#15
Chapt. 07
#16
30°N
20°C
20°C
30°S
Chapt. 07
Salmon Watch — Spawning
Ground
#17
Chapt. 07
Salmon Watch — Mating
Season
#18
Chapt. 07
#19
水溫（℃）
20
15
10
5
8/4
1995
2/20
1996
9/7
3/26
1997
10/12
日期
4/30
1998
11/16
6/4
1999
Annual WT Fluctuation at the Dam 1
of the Chichiawan Stream
Chapt. 07
Middle Section of Chichiawan
Stream-1
#20
Chapt. 07
#21
20
18
水溫（℃）
16
14
12
10
8
8/4
1995
2/20
1996
9/7
3/26
10/12
1997
4/30
1998
日期
11/16
6/4
1999
Annual WT Fluctuation between the
Dam 1 and Dam 2 of the Chichiawan
Stream
Chapt. 07
Middle Section of Chichiawan
Stream-4
#22
Chapt. 07
非生物性因子
光--光質 強度 日照長度
溫度—耐受性（廣溫性，狹溫性）
水—降水量、雪水覆蓋、冰覆蓋、溼度
空氣—氣體種類和分壓
土壤—基底substrate
無機鹽（生物鹽類biogenic salt）
#23
Chapt. 07
非生物性因子
光--光質 強度 日照長度
溫度—耐受性（廣溫性，狹溫性）
水—降水量、雪水覆蓋、冰覆蓋、溼度
空氣—氣體種類和分壓
土壤—基底substrate
無機鹽（生物鹽類biogenic salt）
#24
Chapt. 07
#25
Chapt. 07
#26
Chapt. 07
生物性因子的作用
（一）共生
（二）天敵
（三）競爭
（四）抑制
（五）傳播
#27
Chapt. 07
生態因子對生物的作用的特徵
(一)相互聯繫的綜合作用
(二)主導因子的作用
(三)耐受性定律
(四)最低量律
#28
Chapt. 07
Physical Variables and Species
Abundance
• Liebig’s Law of the Minimum
(1840)
– The distribution of a species will
be controlled by that
environmental factor for which the
organism has the narrowest range
of tolerance
– Optimum range (Figure 7.1)
#29
Population density
Chapt. 07
#30
Lowest limit of tolerance
Highest limit of tolerance
Physiological optimum
Inability
to survive
Low
tolerance
Low
tolerance
Inability
to survive
Species
absent
Low
population
Low
population
Species
absent
Physical gradient
(e.g., pH)
Chapt. 07
Physical Variables and Species
Abundance
• Liebig’s Law of the Minimum
(1840) (cont.).
– Effects of competition (Figure
7.2)
#31
Chapt. 07
#32
Wavy hair grass
Sheep’s fescue
Relative species performance
(Deschampsia flexuosa)
3
4
5
6
7
(Festuca ovina)
8
Small scabious
4
5
6
4
5
6
7
8
7
8
Common sorrel
(Scabiousa
columbaria)
3
3
(Rumex acetosa)
7
8
3
4
pH at 2 cm depth
Ecological optimum curve
Physiological optimum curve
5
6
Chapt. 07
Physical Variables
– Organism’s inability to regulate
body temperature (cont.).
• Distribution of Larrea tridentata
(Figure 7.4)
#33
Chapt. 07
#34
40
Latitude
35
30
Minimum temperature
Less than -16°C
Less than -20°C
25
125
120
115
Longitude
110
105
100
Chapt. 07
Physical Variables
– Organism’s inability to regulate
body temperature (cont.).
• Distribution of vampire bats (Figure
7.5)
#35
Chapt. 07
#36
30°
20°
10°
Recent records
Fossil records
Mean minimal temperature for January, 10°C
110°
100°
90°
80°
Chapt. 07
#37
Physical Variables
• Temperature (cont.).
– Mean temperature vs. Extreme
temperatures
• Frequency of extremes limits species
• Ex. Agriculture and occurrence of
freezing temperatures
– Distribution of oranges in Florida
Chapt. 07
#38
Physical Variables
• Ex. Agriculture and occurrence of
freezing temperatures (cont.).
– Distribution of coffee in Brazil
– Correlations between temperature
and species distribution
• Temperature maps may not coincide
with what organisms experience
Chapt. 07
#39
Physical Variables
• Temperature maps may not coincide
with what organisms experience
(cont.).
– Movement from sun to shade
environments
• Temperature at the local scale, is
much more variable
– Ex. Microclimates of a tree
» South-facing vs. north-facing canopy
Chapt. 07
#40
Physical Variables
– Ex. Microclimates of a tree (cont.).
» South-facing vs. north-facing canopy
» Soil surface to top of canopy
– Ex., Rufous grasshopper
» Restricted to steep sunny slopes
» Combination of time and temperature
is important
• Degree-days determine development
Chapt. 07
Physical Variables
– High temperature
• High temperatures denature proteins
(temperatures above 45°)
• Organisms effectively cool
themselves through water loss
• Life-history stages resistant to high
temperatures
#41
Chapt. 07
#42
Physical Variables
• Life-history stages resistant to high
temperatures (cont.).
– Resting spores of fungi
– Cysts of nematodes
– Seeds of plants
» Ex. Dry wheat grains (90°)
» Thermus aquaticus (67°)
» Thermophilic bacteria (100°;
Figure 7.6)
Chapt. 07
#43
Physical Variables
– Fire
• North America before the aArrival of
Europeans
– Fires started by lightening
– Frequent and regular
– Consumed leaf litter, branches and
undergrowth before great quantities
accumulated
Chapt. 07
#44
Physical Variables
• North America before the arrival of
Europeans
– Large trees usually not damaged
– Some species evolved to require fire
» Pinus banksiana
» Pinus palustris
» Serotinous cones
• Cones sealed with resin
• Require heat from fire to open
Chapt. 07
#45
Physical Variables
• North America after the arrival of
Europeans
– Management practices
» Maintain “natural” environment
» Preventing forest fires
» Produced the opposite
• Change in species composition
• Catastrophic fires (Figure 7.7)
Chapt. 07
#46
Physical Variables
– Global warming
• Two issues
– Rate of global warmning
– Contribution by humans
• Increased global warming =
greenhouse effect
– Atmosphere transmits short-wave solar
radiation
Chapt. 07
#47
Physical Variables
– Atmosphere transmits short-wave solar
radiation (cont.).
» 50% passes through the atmosphere
unaltered to heat the earth.
» Energy absorbed by the earth is
radiated back to the atmosphere as
long-wave radiation
» Long-wave radiation, much is absorbed
by clouds
Chapt. 07
#48
Physical Variables
– A large amount of energy absorbed in the
atmosphere is returned to the earth,
causing the temperature to rise
• Earth requires some "greenhouse
effect"
– Without any greenhouse effect
» Global average temperature: -17°
– With greenhouse effect
» Global average temperature: +15°
Chapt. 07
#49
Physical Variables
• Earth requires some "greenhouse
effect” (cont.)
– Explains hot Venus (blanketed in CO2) and
cold Mars (which has little atmosphere)
• Greenhouse gases
– Table 7.1
Chapt. 07
#50
Chapt. 07
#51
Physical Variables
• Greenhouse gases
– Figure 7.8
Carbon dioxide
340
320
300
280
260
1750 1800 1850 1900 1950 2000
concentration (ppmv)
360
CH
CO
concentration (ppmv)
Chapt. 07
1800
1000
600
1750 1800 1850 1900 1950 200
300
290
280
1750 1800 1850 1900 1950 2000
Year
Year
CFC concentration (ppbv)
N O concentration (ppbv)
Nitrous oxide
Methane
1400
Year
310
#52
0.3
Chlorofluorocarbon-11
0.2
0.1
0.0
1750 1800 1850 1900 1950 200
Year
Chapt. 07
#53
Physical Variables
• Influence of natural sources
– Nitrous oxide
» 2/3 comes from natural soils and
oceans
– Methane
» 1/3 comes from bogs, swamps, and
termites
– Dust and carbon
» Volcanoes
Chapt. 07
#54
Physical Variables
• Human influences
–
–
–
–
–
75% of increases in CO2 emisssions
39% of methane output
36% of nitrous oxide emissions
~50% of all greenhouse emissions
Alterations in land use (~25%)
» Deforestation
» Conversion to rice paddies
Chapt. 07
#55
Physical Variables
– Alterations in land use (~25%) (cont.).
» Increase in domestic animals
» Agricultural soils
– Overall, humans account for 75% of the
increase in greenhouse gases
– Is it possible to replace fossil fuels?
• Evidence of temperature increases
– Temperature record (Figure 7.9)
Chapt. 07
#56
Change from 1940 temperature (°C)
0.4
0.2
0.0
-0.2
-0.4
-0.6
1870
1890
1910
1930
Year
1950
1970
1990
Chapt. 07
#57
Physical Variables
– Temperature record (cont.)
» Problems with record
» Warming has occurred
• Computer models and predictions
– Too many variables to include in a single
computer model.
– Negative feedback mechanisms
– Positive feedback mechanisms
Chapt. 07
#58
Physical Variables
• Computer models and predictions
(cont.).
– UN Intergovernmental Panel on Climate
Change (IPCC)
» 1996 report
» Lack of fit of models
• The formation of other pollutants
– Aerosols of sulfate
– Soot
– Reduce solar heating
Chapt. 07
#59
Physical Variables
• Computer models and predictions
(cont.).
– Emphasizes the complexity of interactions
• Environmental iImpact
– Speed and eExtent of global warming
– Focus on 2100
» Atmospheric CO2 will have doubled
» Temperature will have risen 1
to 3.5° C
Chapt. 07
#60
Physical Variables
• Natural ecosystems
– Profound changes in natural ecosystems
– Most species cannot evolve significantly
or rapidly enough to counter climate
changes
– Most species will not be able to disperse
or migrate fast enough to keep up with
climate change
» Figure 7.10
Chapt. 07
#61
400 km
Chapt. 07
#62
Physical Variables
• Natural ecosystems (cont.)
– Rainfall patterns
» Increase in rainfall (Figure 7.11) in
most areas
• Increase crop production
» Decrease
in some
areas
already
dry
– Ex. Tropical
countries
and rice
production
•
•
•
•
Midcontinental America and Asia
More droughts
More extinctions
Current grain producing areas
would become drier
Chapt. 07
#63
Physical Variables
– Wind
• Can be caused by temperature
gradients
• Amplifies temperature effects on
organisms
– Increase heat loss through evaporation
and convection
– Increases animal evaporation and plant
transpiration
Chapt. 07
Physical Variables
– Wind (cont.).
• Wind aids pollination
• Wind disperses plant seeds
• Affects mortality (Figure 7.12)
#64
Chapt. 07
#65
Physical Variables
• Affects mortality (cont.)
– High winds
– Severe storms
• Modify wave action
– Salt
• Increases osmotic resistance to
water uptake
– Occurs in arid regions
Chapt. 07
#66
Physical Variables
• Increases osmotic resistance to
water uptake (cont.)
– Important to agriculture in arid regions
» Increases salt concentration
» Decreases crop yield
– Salt marshes
» Halophytes
• Adapted to high salt
concentrations
• Ex. Spartina grasses (Figure
7.13)
Chapt. 07
#67
Physical Variables
– pH
• Few organisms can exist below pH
4.5
• Ex. Lake trout in Eastern US
disappear when pH drops below 5.2
• Roots are damaged below pH 3 and
above 9
– Calciphobe: only grow on acidic soils
Chapt. 07
#68
Physical Variables
• Roots are damaged below pH 3 and
above 9
– Calciphiles: only grow in basic soils
– Neutrophiles: tolerant of either condition
– Water
• Protoplasm is 85-90% water
• Distribution of many plants limited by
water availability
Chapt. 07
Physical Variables
– Water (cont.).
• Animal distribution affected by
desiccation
• Tolerance and avoidance
#69
Chapt. 07
Physical Factors and Species
Abundance
• Davidson, Andrewartha, and
Birch
– Thrips (Figure 7.14)
#70
Chapt. 07
Physical Factors and Species
Abundance
• Davidson, Andrewartha, and
Birch (cont.).
– Fed on rosebushes
– Counted every 81 consecutive
days
#71
Chapt. 07
Physical Factors and Species
Abundance
• Davidson, Andrewartha, and
Birch (cont.).
– 78% of variation in population
maxima was accounted for by
weather
#72
Chapt. 07
#73
Physical Factors and Species
Abundance
• Davidson, Andrewartha, and
Birch (cont.).
– Predict the number of thrips using
multiple regressions
• Log y = -2.39 + 0.125a + 0.201b +
0.186c +0.085d
– Log y = log of thrip density
Chapt. 07
#74
Physical Factors and Species
Abundance
• Log y = -2.39 + 0.125a + 0.201b +
0.186c +0.085d (cont.)
–
–
–
–
a
b
c
d
=
=
=
=
winter temperature
spring rainfall
spring temperature
size of overwinter population
– Figure 7.15
Chapt. 07
#75
Observed
Predicted
600
400
200
0
1932
1934
1936
1938
1940
1942
1946
Chapt. 07
Physical Factors and Species
Abundance
• Africa Buffalo and
environmental regulation
– Rainfall and grass productivity in
the Serengeti
– Buffalo density regulated by food
availability
– Figure 7.16
#76
Chapt. 07
#77
25
Number of buffalo per km2
20
15
10
5
500
1000
Rainfall (mm)
1500
2000
Chapt. 07
Physical Factors and Species
Abundance
• Woddell, Mooney, and Hill
(1969)
– Correlation between rainfall and
creosote bush density
– Figure 7.17
#78
12
Chapt. 07(30.5)
#79
Rainfall ( in (cm) )
10
(25.4)
8
(20.3)
6
(15.2)
4
(10.2)
2
(5.1)
1
2
3
4
Density/ 10002 ft (93m2 )
5
Chapt. 07
#80
Physical Factors and Numbers of
Species
• Importance of
evapotranspiration
– Figure 7.18
Chapt. 07
#81
10
20
0
0
30
40
40
10
40
30 60
30
80
100
30
20
120 140
160
180
Chapt. 07
#82
Physical Factors and Numbers of
Species
• Robert Whittaker (1969)
– Four hypotheses explaining
distribution patterns
• Figure 7.19
Chapt. 07
#83
Species abundance
(1)
(2)
(3)
(4)
Environmental gradient
Chapt. 07
#84
Physical Factors and Numbers of
Species
– Four hypotheses explaining
distribution patterns (cont.).
– Competition causes sharp boundaries
among groups
– Competition causes sharp boundaries
between species
– Physical environment causes distinct
boundaries between groups
Chapt. 07
#85
Physical Factors and Numbers of
Species
– Four hypotheses explaining
distribution patterns (cont.).
– Physical environment causes distinct
boundaries between species
– Evidence supports hypothesis (d) above
Chapt. 07
Applied Ecology
• Diseases and gGlobal cClimate
change
• Spread of tropical diseases
poleward
– Controlled by the range of their
vectors
• Ex. Mosquitoes and other insects
#86
Chapt. 07
Applied Ecology
– Controlled by the range of their
vectors (cont.).
• Insects are ectotherms
– Increase in temperature =
increase in range and activity of
vectors
• Ex. Rwanda 1987
#87
Chapt. 07
#88
Applied Ecology
• Ex. Rwanda 1987 (cont.).
– 1° C increase in temperature resulted in a
337% increase in malaria
• Diseases likely to spread
(Box Table)
Chapt. 07
#89
Chapt. 07
Applied Ecology
• Computer model prediction
– Average global temperature
increase of 3° C
– 50-80 million new cases of malaria
per year
#90
Chapt. 07
Summary
• Local distribution patterns are
limited by certain physical or
abiotic factors, such as
temperature, moisture, light,
pH, soil, salinity.
#91
Chapt. 07
Summary
• Temperature is one of the most
important physical variable
affecting plant and animal
distribution
– Resistance to high temperature
and fire
– Implication of climate change
#92
Chapt. 07
Summary
• Wind can amplify the effects of
temperature, and can affect
species distribution directly.
• Soil salt concentration and pH
can affect water uptake in
plants
#93
Chapt. 07
Summary
• Physical factors strongly
influence population densities.
• The physical environment can
profoundly influence species
richness
#94
Chapt. 07
Discussion Question #1
• Why do you think there is a "tree
line" on the sides of many of the
Rocky Mountains beyond which
no trees grow? Is it because of
low temperatures, low water
availability, or high wind? How
would you devise an experiment
to find out?
#95
Chapt. 07
Discussion Question #2
• Do you think an estuary would
be stressful habitat to live in?
Explain. Are there any
disadvantages to living in an
estuary? (Think in terms of
salinity, food availability, and
competition.)
#96
Chapt. 07
Discussion Question #3
• Are you interested in
maintaining buffalo populations
in the United States? Why is
fire so important to achieving
this goal?
#97
Chapt. 07
Discussion Question #4
• What is the value of laboratory
experiments in attempting to
identifying limiting factors to
explain the observed
distribution patterns of plants
and animals in the field?
#98