Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Ecosystems > Lecture 2 > Flashcards

Lecture 2 Flashcards

1
Q

Describe a boreal forest “Tiaga”

A
  1. Freezing temps for 6-8 months
  2. Coniferous forest
  3. 16 million km2
  4. 11.5% of terrestrial ecosystem area
  5. Low tree species diversity
  6. Make up 30% of global forests
  7. Responsible for 20% of carbon uptake
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Describe the arctic tundra

A
  1. Tundra = treeless
  2. Lands beyond the northern tree limit
  3. 5.5% of terrestrial land surface
  4. Above 0 for only 2-6 months of the year
  5. Grasses and sedges and shrubs dominate
  6. Light not limiting
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are some commonalities between arctic and boreal ecosystems (6)

A
  1. Cold - slow decomposition
  2. Short growing season (summer) - low nutrients
  3. Long snow cover duration - freeze tolerant plants
  4. Environmental extremes - low biodiversity
  5. Permafrost - slow growth
  6. High winds, ice abrasion - great longevity
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is GPP

A

Gross primary productivity

Plant photosynthesis of an ecosystem - positive carbon uptake

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is NPP

A

Net primary productivity - remove loss from plant respiration (carbon flux in = less)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is Reco

A

Ecosystem respiration

Soil respiration and plant respiration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is NEP

A

Net ecosystem productivity

Net exchange of carbon GPP-Reco

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is NEB

A

Net biome exchange

Over longer timescales and landscape scales

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is NPP of tundra vs tropical

A

1/10 of tropical

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is NPP of boreal vs tropical

A

1/5

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

How much more c is held in soil than plant biomass in the boreal ecosystems

A

2-3 times more c is held in soil than plant biomass in the boreal ecosystems

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How much more c is held in soil than plant biomass in the boreal ecosystems in the arctic tundra

A

5 times more c is held in soil than plant biomass in the boreal ecosystems

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is a carbon turnover rate

A

The amount of time an atom will stay in an ecosystem once taken up

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What ecosystems have the lingers carbon turnover rates

A

Boreal and mountainous areas

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What ecosystem has the longest carbon turnover rates in the world

A

Tundra

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

NDVI (normalised difference vegetation index)

A

NDVI increased by 20% since 1982 Increasing productivity and growing season caused by climate change

17
Q

What leads to Productivity changes

A

Plants grow more - warming + growing season longer

18
Q

Vegetation change caused by climate change

A

Boreal treeline moving onto tundra - tundra gets warmer so can support more trees - latitudinal treeline advance

19
Q

Boreal treeline advance - evidence from example in Alaska

A

Seedlings at the edge
Oldest trees 1930s - new system with active recruitment
Further into the forest back in time - dead trees in middle of forest
Dynamic system

20
Q

Tundra “shrubification” - greening of the arctic

A

Increase abundance, size and spread of more productive shrubs
Deciduous shrubs
Bigger and taller
Occurring over greater areas

21
Q

Name an example of shrubification

A

Alaska

Increase in shrub abundance 28% (hilltops) to 160% (floodplains)

22
Q

Explain biomass increase vs soil decomposition

A

It was believed that increase in C in more biomass = greater removal of CO2 from the atmosphere
Ignored soil
Hartley studied carbon stores and fluxes in adjacent forest and tundra in northern Sweden
- change in c stock = change if forest moves out onto tundra
- less carbon in forest than tundra
- only shrubs in tundra (less carbon) = above ground
- huge amounts of carbon below ground - twice as much in tundra
- overall 1/3 less total carbon stock in boreal forest than tundra = treeline advance = lose 1/3 of carbon

23
Q

How might C loss happen when treeline advances

A

Priming of decomposition- see directed reading
Forest trees more productive- more photosynthetically active - take up more carbon
Want nutrients to be able to grow so pump carbon below ground into roots = excrete organic acids and enzymes into soil to breakdown nutrients so they can take it up
Nutrients often bound to carbon so when it’s broken down = release carbon = encourage decomposition of carbon in the soil
=> carbon loss moving from tundra to boreal forest
More productive trees cause soil carbon to decompose faster

Ecosystems (3 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions