Lecture 10: Climate change impacts on terrestrial ecosystems

Question 1

IPCC synthesis report 2014

Answer 1

shows impacts CC has on worlds ecosystems

- more current

Question 2

impacts of CC on ecosystems: migration

Answer 2

= polewards (north) migration of species 6.1km advance per decade i.e butterfly spp

Question 3

impacts of CC on ecosystems: changes in time of biological events

Answer 3

changes in the timing of spring events

- 2.3 days earlier per decade

Question 4

effects of CC on natural systems paper =

Answer 4

Parmesan & Yohe 2003

Question 5

woody plant invasion into open ecosystems =

Answer 5

• shrubification
• 1987 - 2013 Alaska
• arctic greening

Question 6

impacts of GC on the worlds ecosystems:

Answer 6

1) Drought-related fires in tropical forests
2) woody plant encroachment in savannas
3) forest dieback during hot droughts
4) resistance to CC in grasslands

Question 7

Fires in tropical forests: droughts during El Nino events __ Tropical carbon sinks

Answer 7

WEAKEN

Question 8

El Nino and La Nina

Answer 8

• -El Nino = warming seas every few years

- - La Nina = cooler sea temps

Question 9

Fires in tropical forests: fires were __ in pre-industrial period

Answer 9

rare 1/2 per 1000 years

Question 10

Fires in tropical forests: trees adaption

Answer 10

not adapted, so when do burn its detrimental

Question 11

Fires in tropical forests: fires have increased because

Answer 11

• forest clearance for agriculture and timber

- peat drainage

Question 12

fires in tropical forests: example –> 97-98 El Nino

Answer 12

• drought
• fires across 16 million ha of tropical forest in Southeast Asia & Latin America
• CO2 emissions = half global fossil-fuel emissions

Question 13

fires are linked to ___ events

Answer 13

severe drought events

Question 14

rainfall has become more ___ and ___ across the tropics

Answer 14

more seasonal and unpredictable

– amazonia experiencing intense wet & dry years

Question 15

woody plant encroachment in savannas: What does this mean?

Answer 15

woody trees enter open canopies

• • replacement of grass w trees/bushes
• common in South African savannas, happens across continents

Question 16

woody plant encroachment in savannas: happens to a greater extent where?

Answer 16

in wetter places!

Question 17

savanna tree density is controlled by

Answer 17

fire & herbivores

• – grow fast enough (tall) to avoid burning & eating
• trees grow tall, grass is outcompeted, shaded
• fires more important in wet (more rain, more grass, more fuel)

Question 18

woody plant encroachment in savannas: is rising CO2 helping trees to escape fire?

Answer 18

• tree growth & root storage depend on atmospheric CO2
• CO2 fertilises CO2, grow faster and escape
• disturbance accounts for some trends also, not just CO2

Question 19

woody plant encroachment in savannas: why do we care? Good CO2 sink?

Answer 19

• livelihoods in savannas
• • pasture for grazing domestic animals (lose cattle)
• • firewood harvesting + charcoal = POSITIVE
• • charismatic animals bring tourism revenue

Question 20

afforestation of grassy ecosystems with exotic trees can ___ carbon stock & water

Answer 20

• degrade underground carbon stocks

- compromise water resources (use up water, issue)

Question 21

Forest dieback during hot droughts: probability of heatwaves ___ in some locations

Answer 21

doubled

– greater frequency of HW in Europe, Asia and Australia

Question 22

Forest dieback during hot droughts: drought trend predictions

Answer 22

hard to predict

Question 23

hot droughts=

Answer 23

atmospheric dries out

Question 24

Forest dieback during hot droughts: greater vulnerability to drought in a hotter world =

Answer 24

1) droughts eventually will occur everywhere
2) warming produces hotter droughts
3) atmospheric moisture demand increases non-linearly w temperature
4) mortality can occur faster in hotter drought

Question 25

resistance to climate change in grassland ecosystems: Buxton Climate Change Impacts Laboratory . What do they do?

Answer 25

BCCIL

• winter warming
• summer watering
• summer drought
  since 1993 26 years

Question 26

resistance to climate change in grassland ecosystems: BCCIL: CC impacts buffered by

Answer 26

1) functional diversity among species

2) functional diversity within species

Question 27

resistance to climate change in grassland ecosystems: BCCIL: CC impacts buffered by: functional diversity AMONG species

Answer 27

• those that are taller, high photosynthesis and tough leaves respond strongly to winter warming
• resource-conservative species with high tissue construction costs respond better to summer drought