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APS124- Ecosystems > ecosystems, climate and environmental change > Flashcards

ecosystems, climate and environmental change Flashcards

1
Q

When did the Devensian cold period range from?

A

115,000-10,000 BP

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2
Q

What are the 5 main stages of the Devensian? (in order and times)

A

Chelford interstadial (60,000 bp), Upton warren interstadial complex (42,000-38,000 bp) ,Dimlington stadial (21,000 bp), windmere interstadial (13,000bp), lochlomand stadial

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3
Q

What is the difference between interstadials and stadials?

A

interstdials are embedded periods of warm conditions whereas stadials are cold

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4
Q

Within the devensian what was the temp and landscape?

A

10c and arctic

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5
Q

Chelford interstadial:

a) 3 types of tree
b) feb and july temp
c) animal species

A

a) birch, pine, spruce
b) feb: -10c, july: 16c
c) brown bear, fox, red deer, reindeer, wooly rhino, elk

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6
Q

Upton-warren interstadial complex:

a) jan and july temp
b) 2 types of flora
c) vertebrate fauna
d) trees?

A

a) jan: -15c, july: 16c
b) arctic alphines, thermophillous species
c) mammoth, bison, wooly rhino, horse, reindeer
d) no trees

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7
Q

Dimlington stadial:

a) what happened to the ice?
b) how was it thought some herbivores were eradicated?

A

a) max. expansion of ice south of uk forming an extensive ice sheet (polar desert/tundra)
b) by paleolithic hunters but more likely due to environment

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8
Q

windmere interstadial:

a) it is a period of what?
b) july temp
c) expansion of what?
d) trees?

A

a) rapid climatic warming
b) 17-18c
c) park tundra vegetation expansion- productive vegetation
d) continuous woodland

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9
Q

lochlomand stadial:

a) july temp
b) why may there have been a return to cold climate before a temp rise again?
c) which trees survived?

A

a) 10-12c
b) disruption of the gulf stream- usually warms uk oceans but freshwater input from melting ice and glaciers can disrupt it
c) birches and pines

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10
Q

How long ago was the post glacial period?

A

10,000 years ago

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11
Q

What did axel blytt and rolf sernander propose?

A

subdivisions of post glacial period based on stratigraphy of peat

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12
Q

Fill in landscape type, time and zone:

Pre boreal-\_\_\_-\_\_\_-\_\_\_
Boreal-\_\_\_-\_\_\_-\_\_\_
Atlantic-\_\_\_-\_\_\_-\_\_\_
Sub boreal-\_\_\_-\_\_\_-\_\_\_
Sub atlantic-\_\_\_-\_\_\_-\_\_\_
A 
subarctic- 9500bc- IV
warmer and dry- 7600bc- V, VI
warm, wet, oceanic- 5500bc- VIIa
warm, dry, continental- 3000bc- VIIb
cool, wet, oceanic- 500bc- VIII
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13
Q

What is goodwin zonation?

A

climatic locations- pollen diagrams proposed by Hockhammere

goodwin applied vompost’s principles to UK

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14
Q

Give examples of zone:

a) I
b) II
c) III

A

a) pre windmere
b) windmere interstadial
c) lochlomand stadial

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15
Q

what species present in zone IV and what is it called?

A

post glacial birch zone

  • birch dominant
  • willows, juniper
  • some pine in south
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16
Q

what species present in zone V, what is it called and what type of climate?

A 
hazel pine birch period
- birch (nw)
- pine in south
-pollen evidence for thermophillous trees
boreal climate
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17
Q

what species present in zone VI, what is it called and what type of climate?

A 
hazel pine period
- pine 
- hazel
- thermophillous trees
- elm
- oak
- lime
- alder
Boreal, dry conditions
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18
Q

what species present in zone VII, what is it called and what kind of conditions?

A

alder/ mixed oak “forest maximum” or “climatic equilibrium”

  • alder
  • oak (n + c +e)
  • lime
  • hazel (ireland)
  • ash
  • less elm, birch and pine
  • warm, wet, oceanic, atlantic, most uk forest
  • 2.5c higher than today
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19
Q

what species present in zone VIII, what is it called and what conditions?

A

alder birch oak beech period
- lime declines
- beech and hornbeam
cooler and wetter

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20
Q

How much of the UK is woodland and what are the 3 main types of natural woodland?

A

12%

native, ancient, recent

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21
Q

3 facts about native woodland

A
  1. 40% Uk woodlands are native (broad leaved deciduous)
  2. have grown in UK since last ice age
  3. UK has 50 species of native trees and shrubs
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22
Q

When was ancient woodland wooded and what would woodland previously have been like?

A

1600 AD

before- natural and native

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23
Q

What is recent woodland and where is it found?

A

planted or established naturally

found on former farmland or heathland

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24
Q

what is primary woodland?

A

survived continually since ice age

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25
Q

what is secondary woodland?

A

planted/ established since last ice age

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26
Q

why do communities occur?

A

environmental factors and community processes

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27
Q

Give 4 examples of community processes

A
  1. competitive exclusion
  2. coexistence through tolerance
  3. coexistence through complementation
  4. dependene
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28
Q

what is community structure

A

the spatial organisation of plant material within a community includes:

  • vertical structure (stratification)
  • horizontal structure (pattern)
  • species abundane
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29
Q

What are the 4 layers of vertical structure?

A 
ground layer
field layer (1-1.5m)
shrub layer (1.5-5m)
tree layer (5m+)
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30
Q

what are the 3 distribution types of horizontal structure?

A

regular (overdispersed)
random
clumped (underdispersed)

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31
Q

What is the pattern shown by a species a product of?

A
  • morphology and growth characteristics
  • seed dispersal mechanisms
  • environmental heterogeneity
  • species interactions
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32
Q

what is species abundance?

A

the amount a species contributes to the vegetation?

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33
Q

according to the national vegetation classification (NVC) how many woodland types and sub communities are there?
What doesn’t the classification take into account?

A

18 woodland types
73 sub communities

does not take into account non vascular plants

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34
Q

In detail, what 4 ways can we measure species abundance by?

A
  1. abundance guesstimates (DAFOR- dominant, abundant, frequent, occasional, rare)
  2. density- no. of individuals per unit area
  3. frequency- chance of finding a particular species in a sample of vegetation
  4. cover (measures as %, can be more than 100% as can be overlapping in dense vegetation
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35
Q

What are plants 2 main approaches to forest floor survival?

A
  • shade tolerance

- complementation (growing when light intensity is relatively high)

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36
Q

a) 6 traits of shade plants
b) do all shaded plants look the same?
c) D.flexuosa example

A

a)

  • large thin leaves with single pallisade layer
  • large SA:weight ratio
  • can lower co2 compensation point
  • maintained at high and low freq
  • respire slower
  • slower growth
    b) no, don’t all have leaves with morphological attributes
    c)
  • narrow, bristle like leaves (grass)
  • tolerates temporary shade as are evergreen
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37
Q

What plants do the complementation approach and what is an example?

A

woodland floor plants- grow before main development of tree canopy
eg: wood anemone

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38
Q

what is phenology?

A

study of sesonal periodicity and timing of plant

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39
Q

when do each of these species grow?

a) vernal
b) aestival
c) autumnal
d) hiemal

A

a) spring
b) summer
c) autum/ winter
d) winter

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40
Q

why may Q.petraea (sessile oak) not be regenerating or producing saplings?

A

acorns may not be viable

unsuitable germination areas

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41
Q

explain C.cymerau N.wales regeneration example

A
  • upland woodland with little vegetation
  • cages round trees to stop mammal interference
  • acorns buried in soil
  • many acorns produced with high viability
  • 99% wastage of fallen acorns (rodent predation)
  • but enough acorns to ensure regeneration
  • ground layer d.flexuosa grazex (intercallary meristem provides tolerance)
  • ground layer important for acorn germination and hiding them from rodents (not good if grazed)
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42
Q

what are the 2 main forest soil types?

A

brown forest soil and podzol soil

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43
Q

what is brown forest soil and whats the average ph of this soil?

A

an active mixing of mineral and organic matter by organisms
no sharp boundaries between horizons
ph 5-7

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44
Q

what is podzol soil and what is the ph?

A
  • no/little mixing by organisms
  • sharp boundaries between horizons due to eluviation of surface horizons
  • surface accumulation of organic matter
  • bleached mineral horizon
  • rusty coloured layer
  • ph<5.5 (acidic)
  • cool, wet climates
  • minerals dissolved in rain brought through soil and deposited in layers
  • nutrients and bases leached from upper horizons
  • litter then peat then iron pan layer and hummus (no iron deposition in humus layer)
  • iron pans can increase water logging
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45
Q

what is a heliophile?

A

sun loving species

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46
Q

in the devensian period what did the grassland environment do to heliophiles?

A

the development of post glacial forests confined heliophiles to naturally open habitats

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47
Q

what did vompost look at?

A

pollen in bogs from this he could tell what plant species were there and where they came from

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48
Q

describe what the elm decline was and when

A

neolithic farming in britain in new stone age
on the pollen spectrum there was a clear decline in elm pollen
unclear as to why (disease, selective cropping, tree pollarding)
1st wave- early 1900s
2nd wave- 1970 (main wave)

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49
Q

a) what caused the landnam clearances and where?
b) from the pollen what can we tell?
c) when did these clearances occur in britain?

A

a) neolithic farmers did small temporary forest clearances in denmark mainly because the brown soil underneath trees was very fertile
b) -decline of trees
- increase in grasses
- increase in grassland herbs
c) 3500bc

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50
Q

when did episodes of extensive and permanent deforestation occur in britain and in which areas?

A

after the elm decline

breckland, wiltshire, dartmoor, sw cumbria

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51
Q

when did the bronze age clearances occur?

A

2100-700bc

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52
Q

when were the iron age clearances, where and what was the result?

A 
500bc
sub-boreal/sub-atlantic boundary
climatic deterioration 
increase in precipitation
increased deforestation
(continued bronze age clearances)
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53
Q

what equipment was used in norman conquest in 1066 for soil clearance?

A

8-ox plough

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54
Q

by 100bc what % of forests were left in britain?

A

20%

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55
Q

how are grasslands mainly managed?

A

grazing and mowing

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56
Q

what is defoliation?

A

removal of part or all of the shoot

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57
Q

what does the apical meristem give rise to?

A

primary plant body

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58
Q

in detail what are the 4 adaptations of grassland plants?

A
  1. intercalary meristem (meristem developing between mature tissue- eg. graminoid species)
  2. adpressed growth (flat to earth- hard to graze/mow- some forb species- negatively phototropic rosettes so not easily grazed)
  3. low palatability (c based spines- low cost, woody tissues, distastefulness, chemical toxins)
  4. ephemeral life history (not around for long- can explot bare earth quickly and grow during periods of limited grazing)
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59
Q

where are nodes and internodes found and what do nodes enable?

A

nodes is the region of leaf attachment
internodes is the region between nodes
nodes enable plant to still grow up even if upper part of plant is lost

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60
Q

what kind of soil do calcicole species grow, and example

A

calcareous soil- S.columbria

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61
Q

what kind of soil do calcifuge species grow, and example

A

acidic soil- N.stricta

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62
Q

is species diversity higher in the north or south and why?

A

south as more limestone grasslands grow here which are species rich

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63
Q

what is the effect of ph on plants mainly mediated by?

A

by its influence on the availability of other ions

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64
Q

what are the 3 main macronutrients in plants and where are they generally found?

A

N,P,K they are found in more neutral soil ph (7-8.5) where limestone grasslands are

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65
Q

as soil ph increases what generally happens to bioavailability of nutrients?

A

increases

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66
Q

where are heavy metals more available?

A

acidic soil

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67
Q

what is the characteristic soil of limestone grassland?

A

rendzina

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68
Q

a) what kind of soil is rendzina where is it, what ph?
b) what is the thin-ness of the soil due to?
c) what is in the A horizon
d) what is the C horizon?
e) P concentration?

A

a) immature, low fertile soil on carbonate with ph >7
b) due to the purity of bedrock as pure limestone provides little insoluble residue and no deep soil profile
c) a thin shallow layer thats stable and crumb like (black/grey/grey brown
d) limestone- usually pure like chalk
e) low conc of available P

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69
Q

at the plateau of a landscape what is the soil like there?

A 
podsol soil
ph <5
low fertility 
<10 sppm2
most of habitat gone due to liming and fertilisation
not eroded quickly
D.Flexuosa
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70
Q

at the slope of a landscape what is the soil type?

A 
rendzina soil
ph>7
>20 sppm2
many calcicoles
F.Ovina
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71
Q

at the valley bottom of a landscape what is the soil like?

A 
brown earth/ alluvium soil
ph 5.5-7.5
high fertility 
5-15 sppm2
A.Elatius
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72
Q

a) what is calcareous grasslands nutrient status like?

A

a) low nutrient status and so high alpha diversity

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73
Q

a) on grimes humpback curve between crop mass 300-900 gm-2 what is there?
b) what does ph help with and what does a low ph result in?

A

a) a corridor of high potential species richness (max) and here species rich and species poor vegetation can occur
b) helps account for variation in richness within the corridor and low ph results in species poor environment

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74
Q

what is the reservoir effect?

A

fewer species are adapted to grow on acidic soils than calcareous soils

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75
Q

what is heathland?

A

physiognomically distinct type of vegetation dominated by ericoid dwarf shrubs

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76
Q

what are the 3 main heather types seen in british heathlands?

A

Calluna Vulgaris
Erica cinerea- bell heather
Erica tetralix- cross leaved heather

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77
Q

what is the species diversity and conservation generally like on heathlands?

A

poor floristic diversity
low nutrient status plants
stress tolerators on acidic soil
vegetation mainly restricted to UK so high conservation status

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78
Q

what 2 uncommon animal species may be found on UK heathlands?

A 
Dartford warbler (S.undata)
smooth snake
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79
Q

Give 6 key facts of upland heaths

A
  1. 300-400m above sea level
  2. up to montane zone (treeline)
  3. 2-3 million hectacres UK
  4. 75% worlds total UK
  5. often called moorland
  6. more upland heaths than lowland
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80
Q

Give 3 key facts of lowland heaths

A
  1. 58,000 ha in UK
  2. 20% worlds total
  3. altitudes <300m
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81
Q

what % of UK total land area is covered by heathland?

A

6%

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82
Q

iron pans in podzol soil causes waterlogging, what does this result in?

A

can stimulate peat formation producing peaty podsols and true peat

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83
Q

what is the largest C reserve in UK and how much carbon is here/

A

peatlands

3 billion tonnes C (equal to 20yrs co2 emissions and britain’s and france’s forests combined)

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84
Q

what conditions are needed for peat formation?

A

anaerobic

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85
Q

when did heathland originate and what did the people do?

A

in/after bronze age and the people cleared forests for vegetation

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86
Q

what did dimbleby notice about bronze age barrows in 1962?

A

that there was fertile, nutrient rich brown earth soil under the barrows (burial chambers in rituals) in N. yorkshire

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87
Q

what may podzolization have occurred in response to?

A

forest clearance and cultivation

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88
Q

what may cause variation in the timing of heather dominance?

A

grazing can suppress heather

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89
Q

when was heather dominant in moors west of sheffield?

A

400AD

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90
Q

when was the most recent extreme heather dominance?

A

post 1800

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91
Q

why is moorland managed?

A

for red grouse shooting which is worth £100 million per year to uk economy

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92
Q

a) what is the subspecies of red grouse (lagopus scoticus scoticus)
b) where is it endemic?
c) what is the food source?

A

a) endemic to UK
b) subspecies of willow grace
c) young heather shoots

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93
Q

how is the moorland managed for red grouse?

A

rotational burning on an 8-15 year cycle

  • maximises amount of edible biomass
  • provides patches of more mature heather for nesting
  • stops heather from ageing so its canopy opens
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94
Q

where are nutrients lost from meaning that moorland soil is nutrient poor and how may the loss be balanced?

A

lost via ash (leaching)- but my be retained in litter and upper soil
also lost in smoke- N (needed for plant productivity)
may be balanced by rainfall input but often not enough

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95
Q

which 3 nutrients are most at risk of being depleted by burning?

A

N (smoke) , P (leaching) , S (smoke) - critical as will limit growth

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96
Q

are afforestation schemes be remunerative and what trees are usually used?

A

yes are financially rewarding and most use exotic conifers ( sitka spruce) from western north america

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97
Q

what may be some issues with afforestation?

A
  • loss of diversity/ distinctive species

- loss of visual appeal/ amenity value

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98
Q

what 2 factors need to be considered for afforestation and which plantation type is the most -ve

A
  1. age of plantation- older trees more visually pleasing
  2. conifer plantations species poor
    evergreen plantations have a -ve side
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99
Q

explain the reforestation example in north yorkshire broxa forest

A
  • possible to grow birch- good at improving soil nutrient status
  • after 70 years trees small and contorted- no commercial value
  • no greater biodiversity than if coniferous trees were planted on the same soil
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100
Q

explain the reforestation example for the tulchan forest on perthshire

A
  • birch planting found to be successful
  • led to increase in earthworm numbers
  • was a gradual breakdown of old calluna mor hummus into mull like form (podzol -> brown forest)
  • decrease in H
  • increase in Ca and P
  • increase in ph
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101
Q

what % of water can be in wetland soil?

A

95%

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102
Q

what 2 main categories are wetlands divided into?

A
  • aquatic wetlands (shallow water)

- telmatic wetlands (wet terrestrial)

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103
Q

what are telmatic wetlands divided into?

A
  • ephemeral seasonal wetlands such as marsh
  • stable permanent wetlands such as swamps which are inundated for most of year and also into acidic bogs and base rich fens which are only inundated for part of the year
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104
Q

what is vegetative succession?

A
  • gradual directional change in vegetation composition
  • populations successively replace one another
  • usually alongside environmental change
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105
Q

what are characteristics of marshes?

A
  • transition between aquatic and terrestrial
  • dominated by grasses, rushes, reeds and other herbaceous species
  • nutrient rich stagnant/ slow moving water
  • seasonally affected
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106
Q

what are characteristics of fens?

A
  • surface and subsurface inflow and outflow
  • tend to be alkaline
  • can reflect chemistry of the geology
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107
Q

what are characteristics of bogs?

A
  • water mainly from precipitation

- organic accumulations contribute to acidity

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108
Q

what is allogenic succession?

A

succession driven by environmental change

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109
Q

what is autogenic succession?

A

succession occurs when vegetation induces environmental change

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110
Q

what is primary succession?

A

autogenic succession that occurs on surfaces that have not previously supported vegetation (mosses)

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111
Q

where does secondary succession occur?

A

on surfaces previously supported by soil and vegetation

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112
Q

what is wetland succession also known as?

A

hydroseral

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113
Q

which 2 main processes does peat accumulate by?

A
  • terrestrialisation

- paludification

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114
Q

describe the process of terrestrialisation and what the 2 main types known as

A

process by which bodies of open water become filled with mud and peat

  • rooting terrestrialisation
  • rafting terrestrialisation
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115
Q

describe rooting terrestrialisation

A

-water gradually shallows by accumulation of mud and peat which allows for progressive colonisation by species suited to shallow conditions
- includes infilling of water where mud is deposited in situ or in washed sediments
- includes swamps (immersive perennials can be established)
- includes fern
- includes fen woodland (dry and stable)
- dry deciduous woodland
includes raised bog

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116
Q

what is raised bog?

A 
acidic ombrotrophic (nutrients from precipitation) peat accumulates above level of fen water 
bog moss sphagnum is a key peat forming species in bogs
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117
Q

describe rafting terrestrialisation

A
  • in small sheltered basins similar to rooting
  • open water directly overgrown by mat of peat
  • reduced dependency of succession on shallowing
  • swamp and fens develop by direct colonisation of water
  • water fills up top downwards
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118
Q

what is paludification?

A
  • where once dry land gets wetter, may be from impeded drainage from sea level rise or increased precipitation
  • high moisture levels needed (200 precipitation days per year)
  • blanket bog
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119
Q

how much of the UK is blanket bog?

A

1.5 hectares (15% of worlds total)

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120
Q

what causes the development of blanket bog?

A
  • ombrogenous formation
  • capacity to blanket terrain
  • oceanic regions with wet and cool climates
  • formation initiated by climate conditions
  • can be found with neolithic artefacts
  • some developed over cultivated land
  • initiated by forest clearance
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121
Q

give 3 features of waterlogged environments

A
  1. saturated with water (may be in episodes)
  2. oxygen deficient (o2 diffusion is 2x slower in water than air and o2 has low solubility in water)
  3. redox related chemical changes (chemical species reduced are more toxic to plants which affects availability of o2, no3, mn, fe, s (mn and fe toxic)
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122
Q

what 3 conditions help to retard process of decomposition in waterlogged environment?

A
  1. anoxic environment
  2. abundance of toxins
  3. acidic conditions
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123
Q

what is one of the main reasons peat accumulates?

A

retarded decomposition

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124
Q

what are 2 waterlogging problems for plants?

A
  1. oxygen deficiency for underground organs

2. increased availability of soluble phytotoxins (mn, fe, s)

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125
Q

what are 3 adaptations of roots to o2 deficiency?

A
  1. anaerobic respiration in roots
  2. transport of o2 to roots
  3. release of o2 into rhizosphere
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126
Q

why may some wetland plants have greater capacity for anaerobic metabolism than dryland plants?

A

can accumulate malic acid which is less toxic than ethanol

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127
Q

what is the movement of o2 in wetland plants favoured by?

A

high tissue porosity

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128
Q

what % of the volume of wetland plants is airspaces and how does this compare to dryland plants?

A

60% wetland

2-7% dryland

129
Q

what is porosity provided by in wetland plants?

A

arenchyma (loose parenchyma)
cavities and channels
special oxygenating structures (pneumatophores, stilt roots)

130
Q

what do stilt roots provide?

A

support for the plant

131
Q

what are pneumatophores?

A

upward growing roots that provide porosity

o2 enters through lenticles

132
Q

a) what 2 things may cause oxygenation of rhizosphere?
b) what does this create?
c) what can this then result in?

A

a) -diffusion of o2 out of root
- enzymic oxidation on root surface
b) Creates a small zone of anoxic (aerobic) conditions around the root
c) can result in oxidisation of reduced phytotoxins in rhizosphere, reducing their toxicity and uptake by the plant

133
Q

what is a snorkel and what plant is an example of one?

A

a snorkel helps o2 transport to rhizomes

dead reed stems

134
Q

what can cutting dead stems below water level in winter cause?

A

can cause the plant to drown and die

135
Q

what can o2 release by plants with high rates of radial oxygen loss do?

A

it can oxidise soil enough to permit growth of other plants (dryland as well as wetland)

136
Q

what can facilitate growth of dryland species in wetlands?

A

high rates of water movement

137
Q

what is the distribution like for a daisy (bellis perennis)

A

difficult to asses

well adapted to UK, covers all of It so can deal with varying weather conditions and ph

138
Q

what is the distribution of a sea sandwort like? (honckenya peploides)

A

only found by the coast
halophyte- salt loving
in sands and shingle
adapted to a wide range of temp and ph

139
Q

what is an example of complementary distribution?

A

crowberry and dogwood

don’t tend to occur together or cover the sae areas

140
Q

what 3 factors explain plant distributions?

A
  1. climatic factors
  2. physiographic factors
  3. edaphic factors
141
Q

which of the factors for plant distribution is responsible for main global and regional patterns?

A

climatic factors

142
Q

in UK what are the 2 gradients that determine plant distribution?

A

north/south temp grdient

east/west precipitation gradient

143
Q

what is the global distribution of major biomes described by?

A

temp and precipitation

dry at equator, wet at tropics

144
Q

a) what is the driest and coldest environment type?
b) what is the driest and warmest?
c) what is the wettest and warmest?

A

a) tundra
b) subtropical desert
c) tropical rainforest

145
Q

what are physiographic factors determined by?

A

the landforms of the landscape

  • altitude (lapse rate)
  • aspect (slope direction) influences irradiance received (south facing slopes warmer)
146
Q

for every 1000m increase in altitude what does the temperature change by?

A

-6.5c

147
Q

what are edaphic factors associated with?

A

the soil

148
Q

what are the 3 main functional features of soil?

A
  1. rooting medium
  2. source of water
  3. source of nutrients
149
Q

what are plant resources?

A

commodities consumed by the plant essential for growth
eg: co2, h2o, o2
insufficient = poor growth
excess resources can be detrimental
different species have different capacities to use a level of resource supply

150
Q

what are plant conditions?

A

environmental variables that plants respond to
not consumed
can help regulate availability of resources

151
Q

for photosynthesis across increasing light levels in plants what would be the resource and the condition?

A 
resource= co2
condition= light
152
Q

what is ph and whats the difference between ph4 and ph5?

A

the effective concentration of hydrogen ions in solution
-log[h+]
ph4 has 10X conc h+ than ph5

153
Q

do the 2 species gain, lose or are unaffected in each scenario?

a) competition
b) facilitation
c) parasitism
d) mutualism
e) commensalism
f) ammensalism

A

a) both lose
b) one gains, other unaffected
c) parasites gains, host loses
d) both gain
e) one growing on the other gains, other unaffected
f) one loses, other unaffected (harm caused provides no benefit)

154
Q

when does competition occur?

A

when growth/development of an individual is adversely affected by the presence of another individual

155
Q

what is indirect competition?

A

individuals attempt to obtain the same shared resource
usually resource of limited availability
dependent on density of individuals
can lead to density dependent population control

156
Q

what is density dependent population control?

A

where the population is too high with not enough resources
involves self thinning
- above threshold sowing density no one else reaches maturity
involves high sowing densities
- may be decrease in number who reach maturity
- may be decrease in reproductive output
- ecological and agricultural consequences

157
Q

what is direct competition?

A 
direct antagonism between different plant species 
less common that indirect
-strangulation
-allelopathy (chemical warfare)
-parasitism
158
Q

as an example of direct competition what do strangler figs do?

A

grow up the side of trees producing stems the engulf the tree and eventually kills it

159
Q

explain the allelopathy example of empetrum hermaphroditum (shrub) on pints sylvestris (tree seedling)

A

tube in soil found pine eliminates root competition from shrub
activated charcoal on soil surface absorbs allelopathic compounds leached from shrub leaves as these could inhibit growth of other plants

160
Q

how many species/families of plant are parasites?

A

over 3000 in 17 families

161
Q

a) what % of plants are hemiparasitic and what does this mean?
b) what % of plants are holoparasitic and what does this mean?

A

a) 80% -have chlorophyll, obtain some carbon, nutrients and water from host
b) 20% -600 species, no chlorophyll, obtain all carbon from host

162
Q

a) when does facilitation occur?

b) what does RNE mean and when you remove a neighbour what happens to it?

A

a)when a plant benefits from having a neighbour
especially in extreme environments
b) relative neighbour effect
+ve RNE when neighbour removed and worse growth

163
Q

a) what are the two types of deposition for oxidised N (NOx)

b) what are the two types of deposition for reduced N (NHy)

A

a) wet-> NO3- (nitrate)
dry-> N2O (nitrous oxide)
b) wet-> NH4+ (ammonium)
dry-> NH3 (ammonia)

164
Q

give 2 anthropogenic n-sources and which of the two types of N it is the main source of

A
  1. fossil fuel combustion main NOx (oxidised N) source, dominated by roads, power station, shipping routes
  2. agriculture is the main source of NHy (ammonia from livestock manure)
165
Q

how many kilotonnes of N per yer is emitted by UK?

A

723

166
Q

in detail what 3 factors affect N deposition?

A
  1. distance from source
    - less so for NOx as has long distance dispersal
    - important for NHy as deposited close to source
  2. surface roughness
    - deposition velocities faster on rougher surface (forests)
  3. rainfall
    - greater rainfall can increase wet deposition
    - seeder feeder effect so double dose of pollution
167
Q

which 4 areas have high rates of N deposition?

A
  • upland areas (rain and seeder feeder effect)
  • areas near industrial centres and agriculture
  • forests
  • Peak District and pennines
168
Q

in detail what are the 4 mechanisms of N deposition as an ecological threat?

A
  1. eutrophication
    - expansion of nitrophilous species
    - declines in biodiversity
  2. soil acidification
    - cation depletion
    - enhanced availability of toxic metals
    - reduce plant health/productivity
    - declines In species richness
  3. increased susceptibility of plants to secondary stress
    - herbivory
    - less resistance to pathogen attack
    - drought
  4. direct toxicity to plants
169
Q

describe the dutch chalk grasslands example for N loving species

A
  • species richness low in 1980s
  • biodiversity loss when N deposition
  • expansion of grass brachypodium pinnate
  • led to increase in N deposition
170
Q

with an increase in N deposition what happens to species richness?

A

decline

171
Q

what is UK current average deposition and what does this reduce species richness by?

A

17 kgNha-1yr-1

reduces by 4-5 species

172
Q

what causes floristic diversity to decline?

A
  • increase in soil N

- decrease in soil ph

173
Q

what does N deposition do to:

a) soil ph
b) soil ammonium and nitrate

A

a) decreases

b) increases both

174
Q

a) is more N deposition accumulated by calcareous or acidic grasslands?
b) whats the maximum % of pollutant N deposition accumulated?

A

a) calcareous

b) 75%

175
Q

what is global N deposition estimated to be in 2050 compared to 1990?

A

2 fold greater

176
Q

what % of worlds terrestrial area is biodiversity hotspots and what % of vascular plant species are here?

A

2.3%

50%

177
Q

what was important for UK dec 2010?

A

coldest dec for 100 years

N. yorkshire: -20c

178
Q

what does climate refer to?

A

the average conditions experienced in a region over a long period of time

179
Q

whats the difference between the natural and human enhanced greenhouse effect?

A

in human enhanced

  • less heat escapes into space
  • more remitted heat
  • more greenhouse gases
180
Q

what is the net radiative forcing?

A

difference of insolation absorbed by earth and energy radiated back into space

181
Q

what does short wave radiation do and what can it be re emitted as?

A

warms surface

re-emitted back as long wave

182
Q

what % of global warming is going to:

a) oceans
b) atmosphere
c) continents
d) glaciers and ice caps
e) arctic sea ice
f) Greenland ice sheet
g) antarctic ice sheet

A

a) 93.4%
b) 2.3%
c) 2.1%
d) 0.9%
e) 0.8%
f) 0.2%
g) 0.2%

183
Q

what does the IPCC stand for?

A

international panel on climate change

184
Q

what did R.Revelle and H.Suess propose in 1957?

A

that there would be an increase in co2 due to the exchange between oceans and atmosphere

185
Q

who tracked co2 in atmosphere at South Pole and Mauna Loa?

A

Charles keeling (keeling curve)

186
Q

a) what are the main greenhouse gases and in what %?

b) which 2 of these are better at driving warming than co2?

A

a) co2: (76%)
-fossil fuel and industrial processes: 65%
-forestry: 11%
methane (CH4): 16%
nitrous oxide (N2O): 6%
F-gases: 2%
b) N2O, CH4

187
Q

what does global warming potential (GWP) do?

A

it compares integrated radiative forcing over specified period
how much energy emissions of 1 tonne of gas will absorb over time relative to emissions of 1 tonne co2

188
Q

what is the order and multiplication factors for the GWP of N2O, CH4, CO2?

A

N2O&raquo_space; CH4&raquo_space; CO2

298X. 25X. 1

189
Q

what region produces the most N2O?

A

crop producing regions

190
Q

what % of Europe N2O emissions are from agricultural soil?

A

50%

191
Q

what % of global CH4 emissions are from biogenic sources?

A

> 70% (eg. wetlands)

192
Q

what % of CO2 emissions is from:

a) fossil fuel combustion?
b) electricity and heat production?
c) transportation?

A

a) 87%
b) 41%
c) 22%

193
Q

give 8 consequences of climate change

A
  1. warming
  2. more extreme weather events
  3. changes in precipitation patterns
  4. sea ice loss
  5. melting glaciers
  6. sea level rise
  7. ocean acidification
  8. ecosystem change
194
Q

give 4 examples of (chronic) trend changes

A
  • co2
  • mean temp
  • mean precipitation
  • N deposition
195
Q

give 3 examples of (acute) extreme events

A
  • drought/ heavy rainfall
  • heat waves
  • storms
196
Q

why do extreme events become more frequent with climate change?

A

due to increase in mean
increase in variance
increase in mean and variance

197
Q

what does an increase in the mean temp mean?

A

that very hot weather is more likely

198
Q

what does an increase in variation in climate mean?

A

that extremes are more likely

199
Q

in 2003 how many deaths were there in Europe from the heatwave?

A

70,000

200
Q

how many stations around the world look at monthly mean temp?

A

17

201
Q

what happened in the Philippines typhoon oct 2013?

A

6000 deaths, $8-15 billion damage, subsurface waters 4-5c above average

202
Q

in which 4 things are trends and extremes linked?

A
  • heatwaves
  • droughts
  • precipitation
  • storms
203
Q

what is an extreme:

a) climatically
b) ecologically

A

a) 95 percentile

b) abruptness= magnitude/duration

204
Q

what did Knapp come up with in 2008?

A

the soil water bucket concept

205
Q

what does anoxia mean?

A

water logged

206
Q

how stressed are each of these conditions under frequent ambient events:
a) xeric
b) mesic
c) hydric
and what happens when more extreme events occur?

A

a) usually stressed
b) seldom stressed
c) usually stressed
with extreme events all are intermittently stressed

207
Q

explain the field study example for Konza prairie in Kansas

A

looked at total rainfall and timing between rainfall
lengthened inter rainfall interval
- found more variable soil water content
- found 10% reduction in productivity

208
Q

what happens in an arctic winter?

A
  • ice encasement and ice lenses
  • winter rain on snow events
  • plants covered in ice so food inaccessible
209
Q

what are examples of rain on snow events?

A 
eg. svalbard reindeer 
more rain on snow events means more ground ice 
decline in pop growth rate
Banks island have had 87% decrease
warming means more rain on snow events
210
Q

explain the population fluctuations in the svalbard trophic system

A
  • herbivores: svalbard reindeer, rock ptarmigan, sibling vole
  • consumer: arctic fox
  • large fluctuations
  • close synchrony with herbivores and fox and winter rainy days
  • due to ground ice from rain on snow and no access to plants
211
Q

since 1980 what has happened to the a) land temp in Wales Scotland and N.ireland?
b) sea surface temp

A

a) +0.8c

b) +0.7c

212
Q

what 3 reasons are there for uncertainty when predicting future climate change?

A
  1. natural climate variability
  2. incomplete understanding of earth system processes or of representation in climate models
  3. uncertainty in future man made emissions of GHGs
213
Q

what are examples of external influences of uncertainty for future climate change?

A
  • changes in particles in atmosphere from volcanoes

- suns energy

214
Q

how long is the cycle of solar irradiance fluctuations?

A

11 year cycle

215
Q

a) what is RCP?
b) what is RCP 2.6?
c) RCP 4.5?
d) RCP 6?
e) rcp 8.5?

A

a) representative concentration pathways (greenhouse gas in co2 equivalent)
b) GHG emissions peak between 2010-2020
c) emission peak 2040
d) peak2080
e) contine to rise throughout century

216
Q

a) under RCP2.6 what will sea level rise by before 2100?

b) if RCP 6.5?

A

a) +0.4m

b) +0.7m

217
Q

at which latitudes is there the greatest warming?

A

high northern latitudes

218
Q

by 2050 summer minima how much sea ice could be lost?

A

2/3

219
Q

what is an example of internal processes for uncertainty of climate change?

A
  • interaction between ocean and atmosphere
220
Q

what is El Nino?

A

oscillation of the ocean atmosphere system in tropical pacific
+ve phase warm ocean temp on equator

221
Q

explain the North Atlantic osscilation

A
  • driver of winter climate variability
  • wet winter in Europe
  • +ve phase subtropical high and low Icelantic so pressure difference and so storms
222
Q

what are PDFs?

A
  • probability density functions due to multiple models
  • modelling uncertainty and natural variability then into account
  • probability random variable falls within a particular range of values
223
Q

at 2014 emission rates when is the total quota likely to be used up?

A

30 years

224
Q

by 2080 under medium emissions what happens to winter and summer temp in UK?

A

winter temp: increase 2-3c

summer: increase 2.5-4c

225
Q

by 2080 whats the change in precipitation in winter and summer in UK?

A

winter: 10-30% wetter
summer: 40% drier (in SW)

226
Q

a) what is sea level rise driven by?
b) what is the sea level rise from 1990-2095?
c) by 2080 what will the rise be in London?

A

a) thermal expansion of ocean and melting ice sheets, ice caps and glaciers
b) 12-76cm
c) 40cm

227
Q

why is there less sea level rise in the north than the south UK?

A

as there isn’t an ice sheet covering north anymore so less impact

228
Q

what is the Gulf Stream and what will in weaken by before 2100?

A
  • North Atlantic Ocean circulation which brings warm water from carribean
  • warm water rises, evaporates becomes saltier and dense so sinks
  • will weaken by 50% by 2100
229
Q

a) what % world is ocean?
b) what % of southern hemisphere?
c) what % of northern hemisphere?

A

a) 71%
b) 81%
c) 61%

230
Q

what is the maximum and average depth of the ocean?

A

max: 11,022m
avg: 3,794m

231
Q

what % of worlds habitable volume is marine?

A

> 99%

232
Q

describe the liquidity of water

A
  • water molecules stick together by weak H bonds
  • liquid at high temps and over a wide range
  • life depends on liquid water
233
Q

describe the heat capacity of water

A
  • high specific heat for room temp
  • higher than air (4X by mass and 3500X by volume)
  • ocean stores a lot of heat
234
Q

describe density of water

A
  • denser than air (1000kgm3 compared to 1.2 of air)
  • max density 4c so usually liquid water below ice
  • density provides support animals
235
Q

describe the ‘light’ related qualities of water

A
  • quite transparent to visible light
  • light can penetrate several 100m through clear water
  • red light absorbed before blue light
236
Q

describe sound qualities of water

A
  • sound carries well in water
  • 20c sound travel 4X faster in water than air
  • as density and temp increases so does the speed of sound
237
Q

what is in sea water?

A
  • water and salt
  • 35g salt per 1000g sea water
  • 86% NaCl
238
Q

what is salinity measured in?

A

practical salinity units (PSU)

239
Q

what are the 4 consequences of 35%/35PSU salinity?

A
  1. freezing point lowers to -1.89c
  2. density increases to 1028kgm3
  3. saltier and colder water sinks
  4. sea ice extrudes salt so saltier water underneath
240
Q

how many years has the volume and composition of the ocean remained unchanged?

A

2 billion

241
Q

what is the total metazoan phyla and species endemic to the region for:

a) marine
b) freshwater
c) terrestrial

A

a) phyla: 32
endemic: 11
b) p:14
e: 0
c) p: 11
e: 1

242
Q

what is life in the sea dependent a lot upon?

A

photosynthesis and primary production

243
Q

what % of suns energy do marine photoautotrophs capture?

A

3%

244
Q

what are the two main photoautotroph types in the ocean?

A
  • seaweeds (macrophytes)

- phytoplankton

245
Q

give 3 features of seaweeds/macrophytes

A
  1. benthic (close/on sea bed)
  2. need light
  3. restricted to shallow coastal areas
246
Q

give 7 features of photo plankton

A
  1. small and float so aren’t dependent on coast
  2. throughout oceans
  3. produce 1/2 O2 in atmosphere
  4. 0.5-300 microns diameter
  5. reproduce quick- <24hr at 20c
  6. abundant
  7. tend to sink (life threatening)
247
Q

what are the 4 main classes of phytoplankton?

A
  • cyanobacteria
  • haptophytes
  • dinoflagellates
  • diatoms
248
Q

where are nutrients and light placed in the ocean layers?

A

nutrients sink- bottom

light at the surface

249
Q

if the ocean was homogenous what would that mean for life?

A

life wouldn’t persist

250
Q

what 7 ways can try to overcome the 2 layer ocean dilemma?

A
  1. mixing surface waters by wind
  2. coriolois effects by earths rotation
  3. surface currents from ocean atmosphere interactions
  4. upwelling of nutrient rich deep waters
  5. thermohaline circulation
  6. migrations
  7. phenology variation
251
Q

what is thermohaline circulation?

A
  • cold water sinks at poles, moves towards equator in deep ocean
  • tropical water lifted and mixed
  • heated at surface and moves to poles
252
Q

how do you study past and current climate change?

A

monitor populations or ecosystems over time

253
Q

how may you study impacts of future climate change?

A
  • simulation through manipulation (controlled but lacks realism)
  • gradient studies (out in field but other factors may impact)
254
Q

what proportion of UK priority species have been lost from 1970-2010?

A

2/3

255
Q

in the Thomas et al 2004 survery:

a) how many plant species?
b) birds?
c) butterflies?
d) what did they find for plants?
e) what did they find for birds?
f) what did they find for butterflies?
g) why a greater loss In butterflies than the others?
h) what were issues with the experiment?
i) why may butterfly change be muted?

A

a) 1254
b) 201
c) 58
d) 28% species decreased, +7% median, 6 extinct
e) 54% species declined, -2% median, none extinct
f) 71% species decline, -13% median, 2 extinct
g) insect pop. more responsive to environmental change
h) low invertebrate sampling, higher trophic level extinctions more likely to be recorded, falsely said larger organisms more sensitive
i) clearances of vegetation at earlier age, warming enhanced carrying capacity, conservation measures

256
Q

give 2 examples of how species range changes with warming

A
  1. abundance maintained if move northward/ high altitudes

2. mobile, widespread breeders can track climate change

257
Q

in the hill et al experiment where did butterflies tend to move?

A

northern species: +41m

southern: +22m

258
Q

which organisms have a northern range margin and which is the greatest shift?

A

birds and mammals

insects have greatest

259
Q

why may reptiles and amphibians retreat to southern range margins?

A

they are already at their northern range limit

260
Q

what is the resistance of a plant?

A

ability of plant community to maintain composition and biomass

261
Q

what is resilience?

A

rate of recovery

262
Q

in the limestone grassland study whats the difference between the locations of Buxton, Derbyshire and Whytham, Oxfordshire?

A 
buxton:
- ancient
- low fertility (slower response) 
- sheep grazing increases stress tolerance
- long lived species
whytham:
- lower stress
- shorter lived species
- lower rainfall 
- early successional state so more prone to change
263
Q

for buxton and whytham study what were the manipulation impacts?

A
  • temp: ambient and +3c winter temp

- rainfall: drought, ambient, 20% enhanced

264
Q

was whytham or buxton more responsive to extra rainfall?

A

whytham

265
Q

what is PCA?

A

principle component analysis

closer plots mean similar composition

266
Q

what was the change in plant community composition for buxton and whytham?

A 
buxton= little change
whytham= large divergence
267
Q

what type of plant communities will respond rapidly to climate change?

A

early successional, fertile communities of fast growing, short lived species

268
Q

why is buxton resistant to change?

A
  • infertile system
  • slow growing
  • persistant root and shoot systems
  • rare for establishing new individuals
  • low influx
  • low soil moisture and nutrient variation
269
Q

is an ecosystem that is more or less in succession more responsive to global change?

A

more in succession, more reponsive

270
Q

why may space occupancy be seen as a major barrier to change in systems of long lived plants?

A
  • tensioned landscape
  • under pressure from climate change
  • no current change due to high biomass
  • space is occupied so no new species can move in
271
Q

in arctic ecosystems what is happening to the temp?

A

mean surface temp rising

some areas 2-3c warmer than 1950s

272
Q

what are the stages of polar amplification in arctic ecosystems?

A
  1. snow and ice melt, darker land and ocean surface absorbs more solar energy
  2. extreme topped energy to warming rather than evaporation
  3. warm atmosphere layer shallow
  4. sea ice retreats, solar heat absorbed by oceans more easily transferred to atmosphere
  5. alterations in atmosphere and oceanic circulation can increase warming
273
Q

because there is little plant cover in arctic ecosystems what does this mean?

A

little cooling as no evapotranspiration

274
Q

a) what is permafrost?
b) what % of N. hemisphere is it?
c) what does it store?

A

a) permanently frozen ground
b) 24%
c) carbon and peat

275
Q

what is a drunken forest?

A

where the ground can slump and trees lean over (wetlands can form)

276
Q

how much C in co2 equivalent could be emitted from thawing by 2100?

A

350 pg C

277
Q

what are the stages for +ve feedback on carbon balance in tundra in terms of permafrost thaw?

A
  • C in as plants photosynthesise
  • C out plants respire
  • plants grow quick so more C uptake
  • old C respired
  • ice wedges melt
  • more C in than out (start to thaw)
  • then more C out than in (thawed)
278
Q

how can permafrost impact human societies?

A

ruin roads as dark roads thaw permafrost and snow insulates ground so doesn’t get cold

279
Q

in terms of snow cover how much longer is the growing snow free period the 1970s?

A

2 weeks longer

280
Q

due to a decrease in snow cover what does this result in?

A

increase in tundra ecosystem productivity and respiration

281
Q

what is the decrease in number of days snow cover duration is for autumn and spring?

A

autumn: -0.5 days/decade
spring: -3.4 days/decade

282
Q

what has arctic greening led to?

A
  • increased plant growth
  • more productive plants (shrubification)
  • more C sequestered by greening tundra by 0.2
  • 7-20% of global land C sinks
283
Q

why is sea ice important?

A

reflects heat back, stops planet warming too much but if melts more oceans are exposed and so more warming

284
Q

if global warming stays below 1.5c whats the chance of an ice free arctic?

A

1/100,000

285
Q

if global warming 2c what is the chance of ice free arctic?

A

1/3

286
Q

what are the 4 sea ice types/ habitat types?

A
  • multi year ice
  • first year ice
  • marginal ice zone (fragmented)
  • open water
287
Q

what does changes in timing of melt/retreat and freeze impact?

A

the food availability

288
Q

what are 4 ecological consequences of sea ice decline?

A
  1. timing of retreat affects availability of zoo plankton and forage fish (resources for sea birds and mammals and fish)
  2. sub arctic species expanding north so likely to provide competition
  3. ice bird species declining
  4. some arctic endemic species extinction likely
289
Q

in arctic ecosystems what may happen to pinniped populations/

A

abundance reductions

290
Q

why may pack ice breeding seals have more reproductive failure?

A

late winter/ early spring breeding habitat less stable

291
Q

a) when do models predict polar bears will be eradicated from ice areas?
b) how much of the worlds pop. live in these areas?
c) what is their main prey whose abundance is being reduced?
d) what happens for them as the sea ice thins?

A

a) 50-70 years
b) 2/3
c) seals
d) more fractured and labile so need to walk or swim more which uses more energy

292
Q

what is used to estimate vegetation volume in a quadrat?

A

% cover

293
Q

in a book by Begon, Harper and Townsend what was ecology defined as?

A

study of interaction between organisms and the environment

294
Q

how can leaf temp be increased?

A

by absorption of shortwave sun radiation and long wave IR sky and surrounding radiation

295
Q

how can leaf temp be decreased?

A
  • re radiation from leaf (longwave)
  • convection (between leaf and air)
  • transpiration (leaf to air via stomatal pores)
296
Q

in detail what are the 3 leaf coupling factors?

A
  1. variation on leaf absorptance
    - darker absorb more radiation
    - orientation to sun changes absorption
  2. stomatal residence
    - grr, size, degree of opening of stomatal pores regulates water loss from leaf
  3. boundary layer resistance
    - thickness of air flow near the leaf changes with wind, leaf size/shape
    - if thick theres decreased transpiration and decreased convection heat loss
297
Q

what are 4 environmental factors controlling leaf temp?

A

solar radiation, humidity, air temp, wind speed

298
Q

what are 4 biotic factors affecting leaf temp?

A

leaf colour, leaf thickness, leaf size/shape, stomatal resistance

299
Q

in an experiment how would you:

a) stop transpiration?
b) stop solar radiation?
c) increases evaporative heat loss?

A

a) cover leaf surface with vaseline
b) shade the leaf with card
c) spray with water

300
Q

what are relict Oaklands in N and W Britain dominated by?

A

sessile oak

301
Q

in the early Iron Age what happened to woodland cover?

A

decreased by 50%

302
Q

in 43-410 AD when it was the Roman Empire what happened?

A

heavy plough and increased agricultural equipment so more forest clearances

303
Q

what can be suggested by the fact there were 5 pollen peaks between elm decline and Iron Age?

A

5 clearance phases progressively larger and longer

304
Q

where does the intercalary meristem grow from?

A

meristem at the base of leaves

305
Q

what does the retarded composition of iron pans ensure?

A

ensures the build up of organic matter

306
Q

in an analysis how many years was it predicted wit will take for N and P lost in burn to be replenished?

A

> 12years

307
Q

what does autochthonous mean?

A

organic muds desisted in situ

308
Q

what does allochthonous mean?

A

muds deposited in washed sediments

309
Q

how much ktNyr-1 is deposited from wet and dry deposition to UK?

A

402

310
Q

what do ecosystems provide provision of?

A

food, medicines, raw materials, clean ground water

311
Q

how much pollutant N deposition do grasslands accumulate and what does this do?

A

75%

maintains provision of clean ground water

312
Q

on the keeling curve:

a) feb 2018 reading?
b) 1957 reading?

A

a) 408.59ppm

b) 315ppm

313
Q

why do foxes lag?

A
  • due to abundance of carrion after rainy winter

- delayed influence of decline in prey

314
Q

why does the fox/ svalbard population recover?

A
  • reduced competition for food

- reduced predation from fox

315
Q

where is there the greatest warming?

A

at high northern latitudes

316
Q

in Europe what has spring leaf unfolding advanced by?

what has start of season advanced by?

A
  1. 42dyr-1

0. 67dyr-1

317
Q

what does calluna vulgaris grow from?

A

apical bud

318
Q

why is P availability low in calcareous grassland soil?

A

soil P has low availability at high Ph values of calcareous soil

319
Q

which ecosystem will be affected and how, suggested by the soil water bucket concept with an increase in extreme rainfall?

A

increased stress in mesic ecosystems

APS124- Ecosystems (3 decks)

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