This document provides an overview of the impact of climate change on biodiversity. It discusses how plants and animals have evolved and adapted to changing climates over hundreds of millions of years by migrating to new areas. However, current climate change is occurring too rapidly for many species to adapt. The document highlights several species and ecosystems that are threatened by climate change, such as coral reefs and Arctic species. It emphasizes that biodiversity is important to human economies and well-being.

1. Lecture 5.
Impact of climate change on
biodiversity
Maslin Chapter 5, Burroughs 9.2-9.3, Houghton
pp.101-113
Hawaiian Honeycreeper: endemic to Hawaii,
23 sub-species evolved from common
ancestor (Finch) to fill different ecological
niches

2. Evolution of plants
• Plants evolved along with
changing earth climate
(Burrough fig 9.1).
Currently 300k species
– Pteridophytes (ferns)
emerged from protective
environment of oceans
400Mya
– Gymnosperms (woody
plants with naked seeds eg.
cycads, conifers)
– Angiosperms (flowering
plants with seeds enclosed
in ovary) evolved 120Mya

3. Flowering plants
• Evolved in early Cretaceous 120Mya. Now
dominant form of land plants –
• Diversified in warm climates throughout
Tertiary 50Mya and extended polewards
worldwide.
• Dramatic changes in Pleistocene ice ages
– N. American plants shifted southward parallel to
mountain ranges, ensuring survival
– Europe due to E-W orientation of mountain
ranges, could not migrate south, so many
species became extinct from Europe eg. Kiwi
fruit and Tulip tree (common in China and USA)
(Burroughs p.274)
Tulip tree

4. Geographical Range of species
• The area occupied by a species according to
its physiological tolerance of the
environmental conditions. eg. Date palm
• Plants more threatened than animals by
change, as cannot move rapidly in response
Geographical range of malaria mosquitoes

5. Response of plants and animals
to climate change
1. Can move – change of geographical range:
animals better than plants
2. If cannot move fast enough will disappear:
depends on:
Plant/animals dispersal ability
Rate of environmental change
1. Movement may be restricted or blocked by
lack/loss of suitable habitat
2. Some species are key species, and their
loss endangers whole ecosystem

6. Since the last severe frost in 1991,
tropical plants have migrated 200m
up Tai Mo Shan

7. Plant migration at LGM: Tropical rain forest
Vegetation zones in Asia

8. ASIA
Tropical
rain forest
extent
during
LGM
Stippled area – probable rain forest refugia
White area – probable savanna grassland
Thick line – present coastline
Thin line- coastline at LGM 20Mya

9. ICE AGE
EUROPE
Woolly Mammoth extinct
Musk Ox survived

10. Mammal extinctions end of last
ice age
• Disappearance of cold-adapted mammals - woolly
mammoth, woolly rhinoceros, wild horse,, musk ox,
bison from 12kYa
• All these survived many ice ages last 2m yrs,
migrating with changing climate to refugia and their
population fluctuated
• Recent research in Nature on genetic and
archaeological data - due to climate warming
combined with spread of humans: found remains of
animals and humans together eg. bones converted
to spears
http://www.nsf.gov/news/news_summ.jsp?cntn_id=122133

11. Explanation of extinctions
• Bison, woolly mammoth, woolly rhinoceros and
wild horse now extinct
• Reindeer and musk ox better cold-adapted than
humans so can survive in Arctic climate
inhospitable to humans – Greenland,
Scandinavia and N America
• Evidence that something changed between
previous, and the most recent glacial cycle
• Our human ancestors able to change landscape
so dramatically that animals were cut off from
what they needed to survive

12. Climate change and Hong Kong
Vegetation zones in Asia

13. Hong Kong is on Climatic Edge of
Tropics
• Tropical plants only found at low altitudes
• Frost damage to plants on mountains
At highest point on Tai
Mo Shan 957m, frosts
occur in most years and
mean January
temperature is 11.1degC
and tropical plants are
damaged- they are at the
limit of their altitudinal
range
Damage to woody tropical plant on 28th
December 1991

14. Current situation: main semi-natural
habitats
Lowland Forest
Montane Forest
Grassland
Shrub
Shrubby Grassland
Coastal mangrove and wetlands

15. Climate change predictions for 21st
Century
• All of Hong Kong will enter the biological tropics.
This will
• eliminate the high altitude refuge for non-tropical
plants
• Permit invasion of plant and animal species that
are currently excluded by cold winter
temperatures
• There is no land directly south of HK so these
will be human-dispersed weedy species that are
already here eg. Mikania micrantha

16. Hong Kong’s non-tropical species

17. Urban and agricultural development north of HK will
make poleward migration impossible for most species

18. Examples of what may happen in Hong Kong
Invasion of weedy exotic Mikania micrantha in HK’s
country parks, and recent invasion of Mai Po Nature
Reserve by a mangrove Sonneratia caseolaris
which does not normally occur north of Hainan
island

19. Species endangered by climate
change (IPCC 2007) (Maslin p.199)
African Mountain
gorilla
Andean Spectacled
bear
Bengal tiger
Forest birds in
Tanzania
Polar bears and
penguins near poles
Main reason-
unable to
migrate due to
geographical
location/
encroachment
by humans
(farming &
urbanisation)

20. Ecosystems endangered by
climate change: Arctic
• Decline in sea ice
• Decline in ice algae
which thrive in
nutrient-rich ice
pockets
• Decline in
zooplankton
• Decline in Arctic cod
• Decline in seals and
polar bears

21. Coral reef ecosystems (Maslin p.100)
• Valuable for fisheries, recreation, tourism
and coastal protection
• Largest global store of marine biodiversity
• Recent unprecedented decline (30%
affected globally)
• El Nino of 1998 with record SSTs, caused
coral bleaching (expelling of algae that
live within it)
• Happens when water >24º
C

22. Predictions of spp. loss by 2050
• Huge future threat to regional
and global biodiversity
• Examined key regions - Mexico,
Amazonia and Australia
• Climatic changes predicted by
IPCC would cause loss of 18-
35% (average 24%) of species
Thomas, C.D. et al, 2004. Feeling the heat: climate change and biodiversity loss. Nature 427:145-148
Example of Boyd’s
forest dragon
(Hypsoluris boydii) of
Queensland Australia:
90% of its range
climatically unsuitable
by 2050

23. Why is biodiversity important?
• At least 40% worlds economy and 80% of
need of poor derived from biological
resources
• Free ecosystem services
– Soil bacteria and recycling
– Interdependency in ecosystems
– Store of genetic diversity
– Pollinators: bees more important to human
nutrition than poultry
– others

24. The Gaia Hypothesis (Lovelock 1979)
• Stresses unity of the earth and interdependence
between living systems and physical and
chemical environment that surrounds life
• Chemical composition of earth very different from
those of neighbouring planets eg. Mars, Venus’
atmospheres almost all CO2

25. • Earth’s atmosphere 77% N, 21% O, only
0.3% CO2 and unchanged over many
millions of years
• Surprising since this not in equilibrium: kept
in steady state (equilibrium) due to
presence of life
• Also, since beginning of life, solar output
increased by 35%, but earth temperature
stable
Influence of life

26. Influence of life
• Early earth very hot, atmosphere almost all CO2
from
volcanic activity
• Volcanoes also released steam(H2O) and NH3.
• Primitive life appeared 3500Mya ago -evolution of CO2
-
using plants released O2
into atmosphere. Some O2
at
highest levels combined with sunlight to form Ozone. The
O3 allowed animals to emerge from water where they had
been protected from UV radiation
Examples of primitive plants
Cyanobacteria Cooksonia (early
vascular plant)

27. Evolution of
living things
420 m a

28. Current earth atmosphere
• Enough O2
for animals
and humans to evolve:
plants and some
bacteria use CO2
and
give off O2, animals use
O2
and give off CO2
• How convenient! - the
atmosphere on which
life depends was
created by life itself
Enough O3
to permit animals to
emerge from water

29. Earth as a living entity
Earth compared to Redwood Tree
97% of tissues are dead
Trunk and bark are dead
Only small % cells along periphery of trunk living
Is the tree dead, or a living entity?
This layer compared to Lithosphere: (thin layer of organisms spread across earth’s
surface, protects living tissues allows exchange of biologically important gases O2
and CO2 )