Lecture 4 - Landscape and Vegetation

Question 1

Canada’s boreal forest is the ____ remaining _____ forest since many rainforests are degraded

Answer 1

largest

intact

Question 2

What is the distribution of forest types in the boreal forest?

Answer 2

tundra above
deciduous hardwood below
montane coniferous north west
aspen parkland and prairie grassland southern

Question 3

Describe Taiga

Answer 3

floristically poor biome
relatively few tree species
mainly conifers
smattering of broadleaf trees
- mostly along waterways

Question 4

9 dominant tree species

Answer 4

black spruce
white spruce
tamarack
jack pine
lodgepole pine balasam bir

Question 5

what makes spruce (black and white) specialized for boreal ecosystems?

Answer 5

shallow root system allowing them to grow in active layer since it is difficult to penetrate permafrost

Question 6

what makes conifers so successful?

Answer 6

can handle cold, drought, low nutrient conditions
conical shape (shed snow and prevent loss of branches)
dark colour (absorbs max heat from sun)
needless leaves (adapted to drought)

Question 7

benefits of needles over leaves

Answer 7

narrowness reduced SA for waterloss
needles with tick waxy coating prevents water loss
stomata are sunken and protected

Question 8

define growing season

Answer 8

period in the year which temp are high enough for photosynthesis

Question 9

what are the impacts of melting permafrost in the

a) tundra
b) taiga

Answer 9

a) thermokarst lakes

b) drunken trees

Question 10

why is soil so nutrient-poor and cold?

Answer 10

acidic drops off needles into soil and slows down decomposition, leaching nutrients and minerals deeper into soil

• shady year round under canopy since trees intercept solar radiation and snow
• leading to more permafrost development and reducing soil temp

Question 11

Most conifers are ______ species - hoard minerals

Answer 11

accumulator species

Question 12

what is an accumulator species?

Answer 12

accumulated nutrients aren’t recycled since they don’t lose leaves
*requires fire to break down dead plants and release nutrients

Question 13

what is mycorrhiza? Plants where often have this?

Answer 13

interweaving of roots

Question 14

mutualism between plants and ______ is important in boreal ecosystems

Answer 14

fungi

Question 15

the boreal forest is divided into 3 zones based on tree cover.

Answer 15

closed boreal forest (S)
open boreal forest (N)
Forest-tundra ecotone

Question 16

what determines N treelike?

Answer 16

the lack of summer warmth rather than extreme cold winters

• limit of tree growth

Question 17

Krummholz definition

Answer 17

continual exposure to fierce, freezing winds that cause vegetation to become stuted

Question 18

what are flagged trees?

Answer 18

branches only grow on one side

snow may protect bottom

Question 19

what is predicted to happen to the treeline as the arctic warms?

Answer 19

trees should be able to persist further N where there is enough moisture

Question 20

how were boreal peatlands formed?

Answer 20

retreating glaciers left behind holes created by melting blocks of ice
water couldn’t drain bc permafrost

Question 21

cold water layer of peat lands is colonized by what?

Answer 21

sphagnum moss

Question 22

peatlands are considered a ______ sink, why?

Answer 22

carbon sink

stores O.Carbon that would otherwise be release into the atmosphere

Question 23

warming will change the carbon balance on the tundra from ____ to ____. why?

Answer 23

sink to source

decomposition will occur faster

Question 24

what are the 3 most abundant GG

how long do each of them last in the envr

Answer 24

Water vapour - 9 days
CO2 - 30-65 years
Methane - 12 years

Question 25

describe the positive feedback loop between increase temp and CO2 production

Answer 25

higher temp increase rate of decomposition, increasing CO2

higher temp, increase fires, releasing more C trapped in peat

Question 26

bogs vs fens

Answer 26

bogs= ombrotrophic
- receive all water and nutrients from precipitation
(all bogs are peatlands)

fens= minerotrophic
- water supply comes from mainly streams or springs
(CAN be peatlands and mineral wetlands)

Question 27

do bogs or fens have more plant species?

which is more widespread?

Answer 27

fens have more

bogs are more widespread

Question 28

what is responsible for most organic buildup in extensive peatlands?

Answer 28

sphagnum

Question 29

what plant genus covers the most land surface globally?

Answer 29

sphagnum

dominance used on ability to absorb and retain water

Question 30

how is sphagnum adapted to wet environments?

Answer 30

closely pack sphagnum creates columns of moss that wick away moisture up to top of sphagnum hummock (capillary action)

• Hyline cells (water storage)
• ->also responsible for acidification
• spread mostly by spores
• start to divert water (cutting off nutrients competitors need)
• produce acid that kills plants that can’t tolerate it
• high acid, low o2 kills decomposers, dead material increases

Question 31

what plants are adapted to cold, low nutrient soils?

Answer 31

leatherleaf
labrador tea
bog rosemary
pitcher plant

Question 32

what are 4 common vegetation patterns of the tundra?

Answer 32

sedge meadows
tussock tundra
wet tundra
shrub tundra

Question 33

describe sedge meadows

Answer 33

flat or rolling terrain dominated by a mat of grass-like sedge plants

sedges and cottongrasses

Question 34

describe tussock tundra

Answer 34

species type of sedge meadow derived from dense clumps of cottongrass

Question 35

describe wet tundra

Answer 35

standing water remains over most of the summer

Question 36

describe shrub tundra

Answer 36

low arctic, vegetated with willow, dwarf birch

• lemmings do well here
• snow trapped by shrubs

Question 37

list 3 vegetation patterns in far north

Answer 37

fell fields - stony tundra, vegetation thin and discontinuous
polar steppe - similar to fell fields butdry fine-grained soil, silt/sand
polar desert - far N, barren areas, lichen most important