Bài giảng conservation biodiversity pattern and processes

Biodiversity: Patterns and
Processes


How is biodiversity spatially spread?
Distribution of biodiversity

Origin of Life

Earth history

Heterogenity
of
environment

Pattern
of
herbivory
Complexity
of
environment

Distribution
of
body size
Source: Yves Samyn


Evolution of Biodiversity
• Life on Earth 3.7 - 3.85x109 years old
• Evolutionary history shapes contemporary

physical and biological environment
• Current diversity of species is a product of the
processes of extinction and speciation


An Extraordinary Number
• So far, about 1.5-1.75
million species have
been identified.
• Scientists estimate
that there may be
between 3 and 117
million species.
• Most estimates range
between 13-20
million

Spector ©AMNH-CBC

Cone head katydid


How many species?
Estimated Number of Described Species
Bacteria
9,021 (0.5%)
Archaea
259 (0.01%)

Nematoda Actinopterygii

20,000 (1.1%) 23,712 (1.4%)

Other Vertebrata
27,199 (1.6%)
Other Eucarya
36,702 (2.1%)
Crustacea
38,839 (2.2%)
Other Plantae
49,530 (2.8%)
Arachnida
74,445 (4.3%)

Insecta
827,875 (47.3%)

Other invertebrate
Metazoa
82,047 (4.7%)
Fungi
100,800 (5.8%)
Stramenopiles
105,922 (6.1%)
Mollusca
117,495 (6.7%)
Angiospermae
233,885 (13.4%)


How many species in Vietnam?

Species group

Number of species
known from
Vietnam

Number of species
described globally
(approx.)

Global percentage of
species found in
Vietnam

Terrestrial
plants

13,766

220,000

6.3

Insects

7,750

750,000

1.0

Fishes

3,170

30,000

10.6

Reptiles

286

6300

4.5

Amphibians

162

4,184

3.8

Birds

840

9,040

9.3

Mammals

310

4,000

7.7


Patterns of species description
Thalassinid shrimps

Mammals

Source: Yves Samyn


New Species Described from Vietnam
(1992-2004)
Mammals 8 species
Birds 3 species
Reptiles 22 species
3 Turtles, 15 Lizards, 4 Snakes
Amphibians 31
Frogs and Toads
Freshwater Fishes > 45 species
Vascular Plants 14 genera

Joyce A. Powzyk


Global Biodiversity Gradient
Biodiversity is not
distributed evenly
across the planet:

Source: Sterling ©AMNH-CBC

Source: Kristan Hutchison,NSF: US Antarctic Program

Species diversity for most taxa is
lowest near the poles, and increases
toward the tropics, reaching a peak
in tropical rain forests (may contain
more than half the species on Earth).


Terrestrial biomes
The term biome refers to a major type of terrestrial ecosystem that
typifies a broad geographical region.


Global Distribution of Biodiversity

• Greatest in areas where NPP is greatest
– Terrestrial: toward Equator - Why?
– Aquatic: near shore, marine upwellings –

Why?


Explanations for the latitudinal gradient in
diversity:
1. Historical Perturbations – places that have been
disturbed (e.g. by glaciation) may have fewer
species because of
A. Differential rates of extinction
B. Inadequate time for species to recolonize

2. Differential rates of evolution – places with more
resources or higher temperature may have faster
rates of evolution
A. Speciation faster then extinction
B. More “evolutionary experiments” tried, and
more niches filled


Others:
3. Climatic Stability – stable climate may promote
specialization (and speciation) and reduce
extinctions
4. Harshness – harsh conditions may limit species
numbers
5. Interspecific interactions – biotic interactions
may promote specialization and coexistence and
are more intense in the tropics
6. Habitat Heterogeneity – diverse habitat
structure may permit finer subdivision of resources

and greater specialization
7. Productivity/Energy – greater available energy
may allow for greater numbers of species to
coexist


Species
richness and
temperature
range

Birds

Mammals

Snails


Species diversity and habitat complexity


Species richness and productivity

N. American data


Patterns of
biodiversity

Altitudinal gradient

Altitudinal
gradients
in bird
species
diversity


Earth history
• Break-up of
Pangea in
Laurasia ad
Gondwanala
nd followed
by more
isolation


Carettochelys insculpta
Pelomedusa subrufa
Caretta caretta
Lissemys scutata
Lissemys punctata
Lissemys ceylonensis
Cyclanorbis senegalensis
Cyclanorbis elegans

2
4

16

7

1

24

15

Cycloderma aubryi
Cycloderma frenatum
Trionyx triunguis
Pelochelys bibroni
Pelochelys cantorii
Chitra indica
Chitra chitra
Chitra vandijki
Rafetus euphraticus
Rafetus swinhoei
Apalone mutica
Apalone ferox
Apalone spinifera aspera
Apalone spinifera emoryi
Pelodiscus axenaria
Pelodiscus maackii
Pelodiscus sinensis
Pelodiscus parviformis
Palea steindachneri
Dogania subplana

Amyda cartilaginea
Nilssonia gangeticus
Nilssonia leithii
Nilssonia formosa
Nilssonia nigricans
Nilssonia hurum

12
18

3 C

9
28
14
27
5

21

10

Paleoclimate

29

19

25

6

30
23
32

8
33
11
13
17

26
20

HOT

22
31
20.0

150.0
150.0

Jurasic

125.0
125.0

100.0

100.0

Cretaceous

75.0
75.0

50.0
50.0

PAL Eocene

25.0
25.0

OLI

0.0
0.0

MIO

PQ

COLD


Understanding Vietnam’s Natural History
Biogeography The study of the current and
historic geographic distribution of organisms

• Geological history

• Past and present climate
• Current ecological conditions

A Medusa’s Head orchid
(Bulbophyllum farreri)
Joyce A. Powzyk


Vietnam as a “tectonic mélange”

Kevin Koy/CBC-AMNH


Continental plates and suture zones in
East and Southeast Asia


Dispersal from the Indian Continent 50-40 mya
Family Dipterocarpaceae
~ 550 species
6 deciduous species
Lin
Yangchen

www.sarawakforestry.com

Chris Willis/UCSD

Long-term Climatic Fluctuations
Long-term cooling beginning
~ 65 mya (Tertiary)
Quaternary Ice Ages 2.4 mya
Glacial/inter-glacial periods
•Alternating drier, cooler and warmer, wetter
•Rising and lowering sea levels; creation/loss
of land bridges

Kevin Koy/CBC-AMNH