Terrestrial ecosystem responses to climate change-key concepts

Question 1

Species -> …

Answer 1

Species -> population -> communities -> ecosystems -> biosphere

Question 2

Major challenges facing ecosystems?

Answer 2

Climate change
Invasive species
Hunting/ defaunation
Deforestation

Question 3

Changes in climate will affect at many levels

Answer 3

Physiological and behavioral response of organisms
Population growth
Community structure
Biome distribution, extinction, migration
Productivity and nutrient cycling

Question 4

How biodiversity is responding to these changes?

Answer 4

1) Extinction: Not many examples of species extinct due to (only) climate change. BUT… Golden toad?
2) Phenological changes (Behavioural changes): Observed changes in phenology and consequences of phenological shifts for species’ interactions.
3) Migration
4) Acclimation of physiology
5) Rapid evolutionary adaptation

Question 5

CO2 effects on plants

Answer 5

Enhance photosynthesis (CO2 fertilization effect)
Produce fewer stomata on the leaf surface
Reduce water use (stomata closure) and increase water use efficiency
Increase more biomass (NPP) in normal and dry year, but not in wet year
More carbon allocated to root than shoot

Question 6

What is phenology?

Answer 6

Phenology is the study of seasonal change and timing.

Question 7

Challenges the evaluate phenological trends

Answer 7

1) A primary challenge in investigating long-term phenological shifts is obtaining reliable historical data.
2) It requires long-term standardized monitoring schemes that could provide historical data.

Question 8

Why Pollination is important?

Answer 8

• Pollinators provide one of the most important ecosystem services
• The vast majority of plants is dependent on animal pollination

Question 9

Observations in marine systems: coral reef bleaching

Answer 9

Mass bleaching: when surface sea temperatura (SST’s)1°C or more above summer long-term average for several weeks
Most severe outbreak associated with 1998 ENSO
Probable cause: physiological disruption of algal
symbionts (zooxanthellae)

Question 10

Corals more resilient than first thought?

Built-in resilience?

Answer 10

Algal symbiont switching
Epigenetic change – changes to genes induced by environmental stress
Symbiont and coral animal evolution
Reefs will change rather than disappear entirely, with some species already showing far greater tolerance to climate change and coral bleaching than others

Question 11

How to measure biodiversity responses to climate change

Answer 11

Molecular- genetics

Individual- phenology

Population- adaptation/migration

Community- species composition/interaction

Ecosystem- productivity

Regional and global- models/ remote sensing

Question 12

Carbon dioxide

Answer 12

1) Carbon dioxide is a greenhouse gas and a major contributor to
global warming.
2) Carbon dioxide may be s:mula:ng growth of certain species and altering composi:on and dynamics of even remote ecosystems.
3) Tropical deforesta@on is removing a major store and sink of Carbon.
4) Carbon dioxide dissolving in the oceans is causing ocean acidification.

Question 13

Elevated atmospheric CO2 in an intact forest ecosystem increases…

Answer 13

photosynthesis, water use efficiency, growth, and population biomass of poison ivy.