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Chap.23
Chap.24
Chap.25
Chap.26
Terrestrial Ecosystems
Aquatic Ecosystems
Coastal and Wetland Ecosystems
Large-scale Patterns of Biological Diversity
Smith & Smith (2015) Elements of ecology. 9th. Ed. Pearson.
Part Seven Ecological Biogeography
生態 生物地理學
鄭先祐 (Ayo) 教授
生態科學與技術學系
國立臺南大學 環境與生態學院
Chap.26 生物多樣性的大尺度樣式
Large-Scale Patterns of Biological
Diversity
Smith & Smith (2012) Elements of ecology. 8th. Ed. Pearson.
鄭先祐 (Ayo) 教授
生態科學與技術學系
國立臺南大學 環境與生態學院
Although covering only 6 percent of the land surface, tropical
rain forests contain over 50 percent of all known terrestrial
species.
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Chapter 26 Large-Scale Patterns of
Biological Diversity
 Nearly 1.4 millions species have been identified
and named, though more are discovered each year
 E.O. Wilson (Harvard University) suggested that
closer to 10 million species exist.
 Over evolutionary time, new species evolve while
existing species become extinct.
 Environmental conditions have influenced species
evolution and the resulting biological diversity in
various geographic regions around the world.
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26.1 Earth's Biological Diversity Has
Changed through Geologic Time
 Long-term evolutionary changes have occurred
over geologic time.
 The number of species has been increasing for
the past 600 million years.
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Fig. 26.3 Estimated species richness of fossilized
invertebrates over geologic time.
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26.1 Earth's Biological Diversity Has
Changed through Geologic Time
 Though the number of terrestrial vascular plants
has continuously increased for the past 400 million
years, the dominant groups have shifted
dramatically
 Psilopsids (松葉蕨類)
 Pteridophytes (蕨類)
 Gymnosperms (裸子植物)
 Angiosperms (被子植物)
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Fig 26.4 Pattern of expansion and reduction of major terrestrial
plant groups during 400 million years of plant evolution.
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26.2 Past Extinctions Have Been
Clustered in Time
The pattern of increasing diversity through
geologic time has been accompanied by
several extinction events.
Permian (225 mya)

90 percent of shallow-water marine
invertebrates disappeared.
Cretaceous (65 mya)


Dinosaurs and many other species went extinct.
Caused by asteroid impact which altered
climate, oceanic circulation, and increase in
volcanic and other tectonic activity.
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26.2 Past Extinctions Have Been
Clustered in Time
 Pleistocene (10,000 years ago)
 Ice-Age mammals went extinct (e.g., woolly
mammoth, giant sloth)
 Caused by receding of ice sheets and/or
hunting by humans
 Modern extinctions
 75 percent of extinction since 1600 due to
human activity (e.g., habitat destruction,
introduction of species)
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Fig. 26.5 The geologic
timescale and mass
extinctions in the history
of life. The fossil record
profiles mass extinctions
during geological times.
The most recent mass
extinction occurred during
the Cretaceous, which
wiped out more than half
of all species, including the
dinosaurs.
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26.3 Regional and Global Patterns of
Species Diversity Vary Geographically
There are distinct patterns for species
richness.
Globally, species diversity declines as
you move northward and southward
from the equator.
Several hypotheses offered for the pattern
of species diversity and latitude




Community age
Spatial heterogeneity of the environment
Stability of the climate over time
Ecosystem productivity
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Fig. 26.6 Geographic
variation in the
distribution of (a)
trees in North
America. Contour
lines connect points
with about the dame
number of species.
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Fig. 26.6 Geographic
variation in the
distribution of (a)
mammals in North
America. Contour
lines connect points
with about the dame
number of species.
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Fig. 26.6 Geographic
variation in the
distribution of (a)
birds in North
America. Contour
lines connect points
with about the dame
number of species.
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Fig. 26.7 North American latitudinal gradients in species richness for (a)
trees based on cells of 2.5 x2.5 latitude/longitude. Species richness per
cell is based on range maps for individual species.
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Fig. 26.7 North American latitudinal gradients in species richness for (a)
mammals based on cells of 2.5 x2.5 latitude/longitude. Species richness
per cell is based on range maps for individual species.
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Fig. 26.7 North American latitudinal gradients in species richness for (a)
birds based on cells of 2.5 x2.5 latitude/longitude. Species richness per
cell is based on range maps for individual species.
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26.4 Species Richness in Terrestrial Ecosystems
Correlates with Climate and Productivity
 D.J. Currie and V. Paquin (University of Ottawa,
Canada) found that even though species richness is
correlated with climatic factors, it correlates most
strongly with estimates of actual
evapotranspiration (AET)
 AET is the flux of water from the terrestrial
surface to the atmosphere through evaporation
and transpiration
 AET is positively correlated with net primary
productivity
 Environmental conditions favorable for
photosynthesis and plant growth may give rise to
increased plant diversity over evolutionary time
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Fig. 26.8 Relationship between annual measure of actual
evapotranspiration (AET) and tree species richness for North America.
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26.4 Species Richness in Terrestrial Ecosystems
Correlates with Climate and Productivity
 Currie also found a positive correlation between
potential evapotranspiration (PET) and regional
patterns of mammal and bird species richness
across North America
 PET is correlated with temperature, solar
radiation, precipitation, humidity, and so
forth
 Currie reported a positive correlation between
vertebrate diversity and plant species diversity
 This may be related to the positive relationship
between primary and secondary productivity
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Fig. 26.8 Relationship between annual measure of actual
evapotranspiration (AET) and (a) mammals species richness for North
America.
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Fig. 26.8 Relationship between annual measure of actual
evapotranspiration (AET) and (b) birds species richness for North
America.
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26.4 Species Richness in Terrestrial Ecosystems
Correlates with Climate and Productivity
 Animal diversity is linked to plant diversity
because plants:
 Are a potential food source for animals
 Provide suitable habitat for animals (e.g.,
structural diversity within plant communities)
 Environmental heterogeneity also gives rise to
increased plant species diversity
 Mountainous regions generally support more
species than consistent terrain of flatlands
 In North America, a general increase in diversity
on an east–west gradient relates to an increase in
environmental heterogeneity (diversity)
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26.4 Species Richness in Terrestrial Ecosystems
Correlates with Climate and Productivity
Mountainous regions support greater
species diversity but there is a general
pattern of decreasing species richness
with increasing elevation.

Mechanism for this decrease may be similar to
those involved with increasing latitude (e.g.,
temperature, AET)
The pattern of species richness and
elevation may be confounded

High-altitude communities occupy a smaller
spatial area and tend to be more isolated.
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Fig. 26.10 Relationship between species richness and
altitude for (a) birds species in New Guinea.
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Fig. 26.10 Relationship between species richness and
altitude for (b) mammal species in Himalayas.
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Fig. 26.10 Relationship between species richness and
altitude for (c) vascular plants in New Guinea.
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26.5 In Marine Environments, There Is an Inverse
Relationship between Productivity and Diversity
 Globally, species diversity declines as you move
northward and southward from the equator
 A correlation between species richness and
productivity is not as apparent in the marine
environment
 The primary productivity of the oceans
increases from the equator to the poles
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介形蟲亞綱動物
十腳類動物
磷蝦
Fig. 26.11 Latitudinal gradient of species richness (a) four
groups of pelagic (遠洋) organisms caught at six stations
along 20o W (longitude) in the Northeast Atlantic Ocean.
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等足類
腹足類
雙殼類
Fig 26.11 (b) Three groups of benthic organisms in
the North Atlantic.
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26.5 In Marine Environments, There Is an Inverse
Relationship between Productivity and Diversity
 The correlation of latitude and productivity in marine
environments is opposite the pattern observed for
terrestrial environments
 Except in areas of upwelling
 Seasonality, rather than total annual
productivity, may influence the local patterns of
diversity for pelagic and benthic species
Primary productivity in the ocean is
influenced by seasonal dynamics of the
thermocline and vertical transport of
nutrients
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26.5 In Marine Environments, There Is an Inverse
Relationship between Productivity and Diversity
 The permanent presence of a thermocline in the
tropical ocean waters results in a low but
continuous patter of primary productivity
throughout the year.
 Low diversity in the oceans at high latitudes
may be a result of the Quaternary period of
glaciation that covered much of the polar oceans
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26.6 Species Diversity Is a Function of
Processes Operating at Many Scales
 Local (alpha) diversity is the species diversity of
individual communities
 Quantifying local diversity is problematic
 It is difficult to define community
boundaries
 The relationship between diversity and area
makes it difficult to compare patterns of species
diversity between communities/ecosystems that
differ in size
 Local patterns of diversity change over time
during succession.
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26.6 Species Diversity Is a Function of
Processes Operating at Many Scales
Regional (gamma) diversity is the total
species diversity across all communities
within a geographic area
A comparison of broad-scale patterns can
be confounded by time (e.g., seasonal
changes that affect water temperature,
migration patterns)
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Quantifying Ecology 26.1 Quantifying
Biodiversity: Comparing Species Richness
Using Rarefaction Curves
The estimate of species richness will vary
with sample size

As more samples are taken, more species will
be recorded
An accumulation curve records the total
number of species revealed during the
survey, as additional sample units are
added to the pool of all previously
observed/collected samples

The point at which the curve reaches an
asymptote defines the optimal sample size
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Quantifying Ecology 26.1 Quantifying
Biodiversity: Comparing Species Richness
Using Rarefaction Curves
For a meaningful comparison of the
species richness derived from different
surveys, we must obtain values for the
same sample size for each survey
A rarefaction(稀釋) curve is produced by
repeatedly resampling the total pool of
samples (N) at random, plotting the
average number of species represented by
1, 2, …, N samples

A statistical expectation of the corresponding
accumulation curve over different reorderings
of the samples
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Chap.26 Large-scale Patterns of
Biological Diversity
Ayo NUTN website:
http://myweb.nutn.edu.tw/~hycheng/