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0 - Boreal Ecology > Midterm 3 (80% of exam) > Flashcards

Midterm 3 (80% of exam) Flashcards

1
Q

What effect would this kind of interaction have on species 1 and species 2 (+ or -)?

Mutualism

A

Species 1: +

Species 2: +

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2
Q

What effect would this kind of interaction have on species 1 and species 2 (+ or -)?

Commensalism

A

Species 1: +

Species 2: no effect

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3
Q

What effect would this kind of interaction have on species 1 and species 2 (+ or -)?

Amensalism

A

Species 1: +

Species 2: -

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4
Q

What effect would this kind of interaction have on species 1 and species 2 (+ or -)?

Competition

A

Species 1: -

Species 2: -

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5
Q

What effect would this kind of interaction have on species 1 and species 2 (+ or -)?

Predation (parasite/herbivore)

A

Species 1: +

Species 2: -

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6
Q

Describe this example, and is it mutualism, commensalism, amensalism, or competition?

  • Mycorrhizae
A

Mycorrhizae are a mutualism between plants and fungi.
• the plant provides the fungus with carbohydrates
• the fungus helps the plant get nutrients from the soil, like nitrogen

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7
Q

Describe this example, and is it mutualism, commensalism, amensalism, or competition?

  • Sharks and suckerfish
A
  • Commensalism.

Sucker fish attach themselves to sharks, they get:

  • Transportation
  • Protection from predators - Little scraps of food
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8
Q

Amensalism

A

an interaction where an organism inflicts harm to another organism without any costs or benefits received by itself

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9
Q

an interaction where an organism inflicts harm to another organism without any costs or benefits received by itself

A

Amensalism

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10
Q

Intraspecific vs interspecific competition

A
  • Intraspecific: Within a species (between age classes, between males and females)
  • Interspecific: Between different species
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11
Q

Herbivory

A

the consumption of all or parts of living plants

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12
Q

____ = consume plant parts (mostly green) near the substrate

a. Frugivores
b. Grazers
c. Granivores
d. Browsers

+ give an example

A

Grazers – consume plant parts (mostly green) near the substrate, e.g., snails graze algae, geese graze grass, including roots

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13
Q

____ = consume plant parts (mostly green) well above the substrate

a. Frugivores
b. Grazers
c. Granivores
d. Browsers

+ give an example

A

Browsers – consume plant parts (mostly green) well above the substrate, e.g., deer browse the leaves of shrubs and saplings

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14
Q

____ = consume fruits, often without damaging the seeds within, in which case the relationship is likely to be mutualistic

a. Frugivores
b. Grazers
c. Granivores
d. Browsers

+ give an example

A

Frugivores – consume fruits, often without damaging the seeds within, in which case the relationship is likely to be mutualistic, e.g., primates

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15
Q

____ = seed “predators”

a. Frugivores
b. Grazers
c. Granivores
d. Browsers

+ give an example

A

Granivores – seed “predators”, e.g., mammals, birds, insects

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16
Q

T or F - plant herbivore interactions are constrained in temperate regions.

A

False - constrained in northern regions

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17
Q

2 reasons why plant herbivore interactions are constrained in northern regions.

A

Short growing season =
• Constrains plant growth & reproduction
• Constrains herbivore growth & reproduction

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18
Q

T or F - plant herbivore interactions are constrained in the north, especially at higher latitudes.

A

True

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19
Q

3 negative things caused by heavy exploitation of plant species by herbivores.

A
  • Decrease abundance/diversity
  • Destroy insulating moss layers
  • Change plant communities
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20
Q

3 positive things caused by herbivores.

A
  • Defecate, adding nutrients
  • Alter competition regimes between plants
  • Disperse seeds
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21
Q

2 main ecological effects of herbivores.

A 
1. Can affect plant fitness:
• Reduce plant growth rate
• Reduce plant reproductive output
• Directly as seed predators
• Indirectly by reducing plant biomass
  1. Can control plant distribution and abundance:
    • Alter plant community structure and composition
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22
Q

Describe this cost of herbivory (and give an example): Complete defoliation

A
  • Complete defoliation, precludes reproduction
    e. g., Gypsy moth (Lymantria dispar)
  • Less conspicuous damage may also have significant costs that are more difficult to assess (e.g., grazing of ovules; partial defoliation - decreased carbon budget)
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23
Q

Describe this example of a cost of herbivory: Spruce seedlings and snowshoe hares

A

Spruce seedlings browsed heavily by snowshoe hares
• curtailed height growth
• high rates of mortality

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24
Q

Describe this example of a cost of herbivory: Muskox and Willow

A

• Arctic willow is their main summer food source
• Production of arctic willow positively affects muskox next year
• Abundance of muskox negatively affects willow growth next
year

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25
Q

Describe this example of a cost of herbivory: Moose on Isle Royale

A

Moose browse of deciduous trees and shrubs on Isle Royale caused shift to spruce-dominated forest
• Colonized the island ~1900, decimated vegetation

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26
Q

an organism that modifies, creates or destroys habitats and modulates the availability of resources to other
species, causing physical state changes in biotic or abiotic materials

A

Ecosystem engineer

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27
Q

Ecosystem engineer + example

A

Ecosystem engineer – an organism that modifies, creates or destroys habitats
• modulates the availability of resources to other
species, causing physical state changes in biotic or abiotic materials
• Beavers

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28
Q

Herbivores can limit plant populations, but plants are abundant and herbivores don’t limit plant growth. List the 3 hypotheses for why the world is green.

A
  1. HSS hypothesis
  2. Exploitation ecosystems hypothesis (EEH)
  3. Plants have evolved defences against herbivores
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29
Q

Herbivores can limit plant populations, but plants are abundant and herbivores don’t limit plant growth.

Describe this hypothesis for why the world is green: HSS hypothesis

A

Predators and parasites control herbivore abundance:

  • Carnivores have no predators and are limited only by food
  • Herbivores are limited by predation
  • Producers are limited by competition and resources (not herbivory)
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30
Q

T or F - According to the HSS hypothesis for why the world is green:

  • Carnivores have no predators and are limited only by food
  • Herbivores are limited by predation
  • Producers are limited by herbivory
A

False -

  • Carnivores have no predators and are limited only by food
  • Herbivores are limited by predation
  • Producers are limited by competition and resources (not herbivory)
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31
Q

Trophic cascade

A

influence of producers or consumers on species that are two or more trophic levels away

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32
Q

influence of producers or consumers on species that are two or more trophic levels away

A

Trophic cascade

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33
Q

Top-down Control

A

influence of predators on the relative abundance of lower trophic levels

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34
Q

influence of predators on the relative abundance of lower trophic levels

A

Top-down Control

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35
Q

Bottom-up Control

A

influence of producers on the relative abundance of higher trophic levels

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36
Q

influence of producers on the relative abundance of higher trophic levels

A

Bottom-up Control

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37
Q

Herbivores can limit plant populations, but plants are abundant and herbivores don’t limit plant growth.

Describe this hypothesis for why the world is green: Exploitation ecosystems hypothesis (EEH)

A
  • Effects of trophic cascades usually alternate by trophic level
  • Primary productivity determines the number of trophic levels in an ecosystem

Eg. Sea otters promote growth of kelp beds by preying on sea urchins
- With less sea otters (eaten by killer whales), there’s more urchins, less kelp, and that results in fewer fish and shellfish.

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38
Q

Trophic downgrading of earth

A
  • Reduced food chain length
  • Alters herbivory and abundance composition of primary producers, leading to regime shifts and alternative states of ecosystems
  • Many indirect effects from removing apex predators (fire, disease, atmospheric carbon, soil nutrients, water, invasive species, biodiversity)
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39
Q

Example of an indirect effect of removing an apex predator (trophic downgrading of earth): Rinderpest (wildebeest disease) and fire.

A
  • Rinderpest reduces wildebeest numbers
  • Less grazing on vegetation
  • More fire
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40
Q

Number of trophic levels determined by productivity

A

Bottom-up (trophic control)

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41
Q

T or F - Increased productivity results in an increased number of trophic levels.

A

True

Productivity determines the number of trophic levels, more productivity = more levels.

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42
Q

T or F - Decreased productivity results in a longer food chain.

A

False - results in a shorter chain.

Productivity determines the number of trophic levels, more productivity = more levels.

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43
Q

Bottom-up (trophic control)

A

Number of trophic levels determined by productivity

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44
Q

T or F - vegetation of cold, unproductive areas is predicted to be
under intense grazing pressure.

A

True

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45
Q

Herbivores can limit plant populations, but plants are abundant and herbivores don’t limit plant growth.

Describe this hypothesis for why the world is green: Plant defences

A

Since herbivory is costly to plants – even when it isn’t fatal – plants are expected to evolve defences against herbivores (e.g., mechanical, chemical, developmental, etc).

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46
Q

Examples of these plant defences against herbivory:

  • Mechanical
  • Chemical
  • Developmental or phonological
A
  • mechanical (toughness, spines)
  • chemical (alkaloids, phenolics, terpenoids, latex)
  • developmental or phenological (masting)
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47
Q

3 main types of defences of plants against herbivory.

A
  • mechanical (toughness, spines)
  • chemical (alkaloids, phenolics, terpenoids, latex)
  • developmental or phenological (masting)
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48
Q

This type of plant defence is present in the plant irrespective of attack.

A

Constitutive

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49
Q

This type of plant defence is produced by the plant in response to attack.

A

Induced

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50
Q

Constitutive vs induced plant defences, and an example of both.

A
  • Constitutive – present in the plant irrespective of attack
  • Induced – produced by the plant in response to attack

E.g., Acacia trees that are protected from browsing giraffes produce fewer, shorter thorns
• thorns are constitutive, but exhibit inducible characteristics

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51
Q

Co-evolution

A

• Evolution of two or more interdependent species, each adapting to changes in the other
• Predator/prey
(also competitive or mutualistic species)

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52
Q

• Evolution of two or more interdependent species, each adapting to changes in the other
• Predator/prey
(also competitive or mutualistic species)

A

Co-evolution

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53
Q

Example of predator-prey evolution

A
  • E.g. newt develops toxins so predators will avoid it
  • Predators that are more resistant to the toxin will have advantage over predators without resistance
  • Only the most toxic newts survive
  • The predator evolves more resistance to toxin
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54
Q

Describe this example of coevolution: crossbills and black spruce (and squirrels)

A

In Quebec (mainland), crossbills and red squirrels both eat from black spruce.
In Newfoundland, there’s no red squirrels, just the crossbill.
• Crossbills remove individual seeds by prying open scales of cones
• Squirrels take whole cone & cache (prefer cones with higher numbers of seeds)

Cone adaptations:
• On Newfoundland􏰀 - defences against crossbills
• Larger cones than mainland
• Thicker scales on cones
• Need more force to open – bird must use more energy
• More seeds and heavier seeds than mainland

  • On mainland􏰀 - defences against squirrels
  • Cones are smaller, fewer seeds, small scales
  • White-winged crossbills
  • Eat partially-open cones
  • can get bill in openings

Squirrels:
• Pattern of co-evolution breaks down in the presence of red squirrels
• Red squirrels outcompete crossbills for seeds
• Overwhelm selection on trees by crossbills
• Trees respond to selection from red squirrels instead
• In absence of red squirrels, Crossbills more abundant

Red squirrels introduced to Newfoundland – flourished
• Extensive removal of cones
• Rapid decline of crossbills

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55
Q

Example of a developmental or phenological plant defence

A

Mast seeding (masting) – the synchronous and highly variable production of seeds by a population of plants

  • Abundant seed production followed by a period of paucity
  • Pulsed resource satiates predators, allow seed escape in mast years
  • Huge effect on seed predators

On mast years - squirrels have larger litters, more yearlings breed, and more offspring produced due to increase in resources.

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56
Q

T or F - Female plants invest less energy in chemical defences (like secondary plant metabolites) because they need the energy for reproduction.

A

True (usually).

Non-reproducing plants often have higher concentrations, can afford to invest in secondary metabolites.

  • In arctic willows, females have higher concentrations than males
    • produce more active tissue for seed production & need to protect these tissues
    • concentration of secondary metabolites increases during the growing season
    • Females are eaten less than males
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57
Q

Example of induced production of secondary plant metabolites in oak trees.

A
  • Induced in Quercus robur, a temperate deciduous tree
  • Emissions of secondary compounds from leaves increase in relation to the percentage of leaf area infected with fungus
    • oak powdery mildew
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58
Q

T or F - More tropical plants contain toxic alkaloids than do temperate species.

A

True -
• more toxic in tropics
• due to higher levels of herbivore attack on tropical plants

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59
Q

T or F - herbivory increases likelihood of pathogen attacks on plants.

A

True:

may provide entry points for fungi, bacteria, nematodes, & other pests, parasites, & pathogens to bypass the plant’s external physical defences

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60
Q

Scatter hoarding + example

A

Bird has several piles/areas of seed caches

  • Pine trees and Clark’s nutcracker have a mutualistic relationship where the bird disperses the pine’s seeds by stashing them
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61
Q

T or F - 50% of geese droppings contain viable seeds.

A

False - 80%

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62
Q

T or F - Seed predation will be highest at low elevations and close to the equator, and lower at at the arctic and at high elevations.

A

True

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63
Q

It was experimentally determined that seed predation will be highest at low elevations and close to the equator, and lower at at the arctic and at high elevations.

The large scale patterns were primarily driven by _____.

Interaction strength was higher between _____ and _____.

A

The large scale patterns were primarily driven by invertebrates.

Interaction strength was higher between invertebrates and plants.

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64
Q

T or F - While seed predation Is highest at low elevations and the equator, the large scale patterns were primarily driven by vertebrate and plant interactions.

A

False - invertebrate and plant interactions.

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65
Q

How are bee latitudinal ranges changing and why is this important?

A
  • Pollinators have a keystone function in ecosystem )plants depend on them for reproduction).
  • Range losses on southern extent but not extending north.
  • Bees also moving to higher elevations.
  • Latitudinal range is contracting with climate warming.
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66
Q

T or F - Pollination by insects and animals is most prevalent at higher latitudes.

A

False - wild pollination is (main method), although insect pollination is still important.
• Most flowering plants in high Arctic sites displayed entomophilic (insect pollinated) traits

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67
Q

T or F - Wind pollination is more important with increasing latitude.

A

True - pollination by insects to a lesser extent at higher latitudes BUT is still important.
• Most flowering plants in high Arctic sites displayed entomophilic (insect pollinated) traits

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68
Q

4 reasons why the number of pollinator species may be limited in boreal forests.

A

Oviposition sites (where insects lay eggs) are limited because:

  • Closed canopies
  • Seasonality
  • Severe cold winters
  • Tree species are mostly conifers – wind pollinated
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69
Q

Describe self pollinating plants and issues that come with this.

A 
• advantage when pollinators are few or variable
• but limits variation in progeny and may depress
plant vigor (inbreeding depression)
• E.g. Arctic poppy & Arctic bladderpod
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70
Q

Entomophily

A

pollination by insects

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71
Q

pollination by insects

A

Entomophil

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72
Q

Most flowering plants in high Arctic sites displayed entomophilic (insect pollinated) traits - list 3 attractants.

A
  • Visual, olfactory
  • Nectar rewards
  • Shelter and warmth
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73
Q

Describe the Arctic Rose (Dryas), which is entomophilic.

A
  • Petals arranged parabolically
  • directs suns rays to center
  • warms anthers [male] and stigma [female]
  • Flowers track sun so rays always directed into flower
  • stays warm 24/7
  • Insects find 10°C warmer than ambient air
  • feed on pollen & seek next warm flower
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74
Q

List some examples of pollinators in the high arctic

A
  • Bees
  • Mosquitoes
  • Moths
  • Wasps
  • Beetles
  • Flies
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75
Q

Anthophiles

A

attracted to or feeding on flowers

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76
Q

attracted to or feeding on flowers

A

Anthophiles

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77
Q

Are bees important in the boreal (more so in other regions)?

A

Yes - only 12 species but make up 12.5% of all insects.

In North America there are 54 species making up 4% of all insects.

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78
Q

Why are bumblebees able to survive/pollinate in the high arctic?

A
  • Good overwintering capabilities
  • Generalist feeders
  • Social (can thermoregulate) • important in cold spells
  • Nest in rodent burrows, fallen trees etc.
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79
Q

T or F - Diptera are more important than bees in the arctic, making up 75% of pollinator abundance.

A

True - bees make up 12.5%

• Proportion of Diptera in total pollinator fauna increases with latitude

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80
Q

Topology

A

Connections in food webs (who’s eating who)

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81
Q

Interaction strength in food webs

A

How dependant the predator is on the prey

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82
Q

Trophic level

A

Organisms are grouped into levels (primary producers, primary consumers, etc.) with each dependent upon the preceding level.

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83
Q

Organisms are grouped into levels (primary producers, primary consumers, etc.) with each dependent upon the preceding level.

A

Trophic level

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84
Q

Importance of top predators in marine food webs (short)

A

They couple 2 habitats/energy (benthic and pelagic)

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85
Q

3 ways energy is lost in each trophic level

A

1) Respiration (assimilation – growth)
2) Predation
3) Decomposition

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86
Q

T or F - an organism’s trophic position is relatively constant over time.

A

False, more of a sliding scale where a predator may eat multiple levels beneath it (=trophic omnivory) and thus lower it’s trophic level.

Trophic position is a continuous measure in marine systems (individuals can vary between 2-4 trophic levels).

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87
Q

Trophic omnivory

A

A predator may feed on multiple trophic levels

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88
Q

T or F - Terrestrial food chains are longer than marine ones, in general.

A

False - marine systems have longer food chains

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89
Q

List 6 structural differences between terrestrial and aquatic trophic pyramids.

A
  1. Autotrophs differ in size and growth rate (less structural complexity and more nutritious in aquatic systems).
  2. More similar size structure between predator and prey in aquatic systems.
  3. Nutrient stoichiometry (aquatic systems have more N and P than terrestrial ones, more nutritious).
  4. Specialization (chemical and structural defences more prevalent in terrestrial systems).
  5. Nutrient subsidies (nutrient input from terrestrial systems enters aquatic ones, like C, N, P, aquatic systems are nutrient sinks).
  6. Stronger top down control (herbivore consumption of primary producers is 3-4x greater in water than on land, decomposers are 10x more efficient in water than on land).
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90
Q

T or F - herbivore consumption of primary producers is greatest on land.

A

False - greatest in aquatic systems.

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91
Q

T or F - Decomposition is 10x more efficient in water than on land.

A

True

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92
Q

Describe this structural difference between terrestrial and aquatic trophic pyramids:

Nutrient stoichiometry

A

Nutrient stoichiometry (aquatic systems have more N and P than terrestrial ones, more nutritious).

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93
Q

Describe this structural difference between terrestrial and aquatic trophic pyramids:

Specialization

A

Specialization (chemical and structural defences more prevalent in terrestrial systems).

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94
Q

Describe this structural difference between terrestrial and aquatic trophic pyramids:

Nutrient subsidies

A

Nutrient subsidies (nutrient input from terrestrial systems enters aquatic ones, like C, N, P, aquatic systems are nutrient sinks).

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95
Q

Describe this structural difference between terrestrial and aquatic trophic pyramids:

Stronger top down control

A

Stronger top down control (herbivore consumption of primary producers is 3-4x greater in water than on land, decomposers are 10x more efficient in water than on land).

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96
Q

Describe this structural difference between terrestrial and aquatic trophic pyramids:

Autotrophs differ in size and growth rate

A

Autotrophs differ in size and growth rate (less structural complexity and more nutritious in aquatic systems).

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97
Q

T or F - While terrestrial and aquatic systems have the same net primarily productivity, there’s much faster turnover in aquatic systems.

A

True - also chain length is typically longer and autotrophs have smaller biomass than in terrestrial systems (still same productivity).

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98
Q

T or F - most terrestrial systems have an upright pyramid of biomass, and a negative log relationship between body mass and abundance.

A

True

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99
Q

T or F - most aquatic systems have an inverted pyramid of biomass, and a positive log relationship between body mass and abundance.

A

True ONLY if looking at phytoplankton only. If you include top predators, the pyramid is normal/upright.

A positive log relationship occurs for inverted pyramids though.

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100
Q

T or F - terrestrial (Eltonian) size pyramids have a 10% energy transfer efficiency from 1 level to the next.

A

True

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101
Q

T or F - Trophic efficiency declines with increase trophic level.

A

True -

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102
Q

In which ecosystems would you see an inverted food pyramid?

A

May only occur in communities with allochthonous input (no primary producers, all energy comes from elsewhere) - like the deep ocean.

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103
Q

T or F - A positive slope on a graph of biomass/trophic level vs abundance indicates a typical upright pyramid food level system.

A

False - indicates inverted pyramid

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104
Q

List and describe the 3 hypotheses for sources of variation in trophic structure between different aquatic systems.

A
  1. Productivity hypothesis: Increase in productivity/food = increase in food chain length.
  2. Increase in lake size = increase in food chain length.
  3. Productive-space hypothesis: Highly productive, large lakes = largest chain length.
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105
Q

____ hypothesis: Highly productive, large lakes = largest chain length.

A

Productive-space hypothesis: Highly productive, large lakes = largest chain length.

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106
Q

T or F - lake size alone explains only 30% of maximum trophic position variation. Most of the variation is explained by productivity differences.

A

False - it explains 80% and ecosystem size is key for food chain length.

No effect with productivity.

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107
Q

T or F - The variation seen in trophic position between aquatic ecosystems is almost entirely explained by the size of the lake - not productivity.

A

True - 80% of variation explained by lake size, none by productivity.

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108
Q

Lake size alone explains 80% of maximum trophic position variation in ecosystems. What else influences this, and why?

A

Larger ecosystems have higher maximum trophic position.

This increase is due to lake size and top predators in large lakes.

Increase in trophic position in multiple species with increasing ecosystem size (likely due to lower omnivory by top predators)

  • Ecosystem size and top predators determine food chain length
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109
Q

T or F - Invasive species can cause temporal long term changes in food webs, for example, lowering the TL of a species.

A

True - Invasive species have reduced the TL of a lake trout by out competing it’s previous prey, so it now feeds on zooplankton (reduced TL).

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110
Q

T or F - There has been a longterm decline in the TL of fish communities. If true, describe why, if not, describe what changes are happening.

A

True - driven by a decrease in demersal (bottom feeding) fish + fish are getting smaller (due to increasing fisheries exploitation).

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111
Q

Describe an example of how feeding relationships are changing (e.g. due to climate change).

A
  • Temperate species are expanding northward range due to warming.
  • Beluga whales are feeding less on larger prey (turbot) and now feeding more on smaller forage fish.
  • Warming = less ice, so polar bears are spending more time on land.
  • Feeding less on ringed seals and more on Eider ducks.
  • Brown bears are feeding less on salmon and more on berries due to changes in availability (due to climate change).
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112
Q

Food web omnivory

A

Feeding on more than 1 trophic level (seals feed on fish and phytoplankton).

113
Q

Do fishes inhabiting tropical river–floodplain ecosystems behave as seasonal omnivores, by shifting their trophic positions in relation to the annual flood pulse?

*Rising water in wet season, no flooding in dry season. How is TL influenced?

A
  • Fishes had lower trophic position during wet season by consuming more inverts and plankton.
  • Some had no change while others changed TL by 0.5
  • Species respond differently to flood pulses; some species consumed more inverts but some ate more fish and increased their TL
114
Q

An individual whose niche is substantially lower than the population’s niche for reasons not attributable to sex, age or discrete morphological group.

A

Individual specialist

  • said would be on exam
115
Q

Individual specialist

  • said would be on exam
A

An individual whose niche is substantially lower than the population’s niche for reasons not attributable to sex, age or discrete morphological group.

116
Q

Describe the trophic structure of a generalist in terms of:

  • What a generalist is
  • Their total niche width
  • Within individual component
  • Between individual component
A

Generalist = Uses a wide variety of habitats and resources.

TNW = All the resources/habitats the species is using.
WIC = How consistent their diet is over time.
BIC = How much variation there is between individuals

TNW - same size as for individual specialist.
WIC - wider.
BIC - narrower.

117
Q

Describe the trophic structure of an individual specialist in terms of:

  • What an individual specialist is
  • Their total niche width
  • Within individual component
  • Between individual component
A

Individual specialist = An individual whose niche is substantially lower than the population’s niche for reasons not attributable to sex, age or discrete morphological group.

TNW = All the resources/habitats the species is using.
WIC = How consistent their diet is over time.
BIC = How much variation there is between individuals

TNW - same size as for generalist
WIC - narrower.
BIC - wider.

118
Q

T or F - for an individual specialist, their total niche width is the same as for a generalist, but their within individual component is narrower, and between individual component is wider.

A

True

119
Q

T or F - for an individual specialist, their total niche width is the same as for a generalist, but their within individual component is wider, and between individual component is narrower.

A

False - their total niche width is the same as for a generalist, but their within individual component is narrower, and between individual component is wider.

  • This describes a generalist
120
Q

T or F - for a generalist, their total niche width is the same as for an individual specialist, but their within individual component is wider, and between individual component is narrower.

A

True

121
Q

2 sources of variation in trophic structure due to individual specialization, (based on optimal foraging theory).

A
  1. Intraspecific competition:
    - If population density increases, some will be outcompeted and have to specialize.
    - If resource abundance decreases, some will be forced to use different resources.
  2. Interspecific competition:
    - Species richness
    - Available resources
    - Predation)
122
Q

List a few tools used to study food webs.

A
  • Direct observation → telemetry
  • Stomach content analysis
  • Stable isotope analysis
  • Fatty acid analysis
  • Stomach content DNA analysis
  • Contaminants
123
Q

How can we study food webs using stomach content analysis?

A
  • Quantify diet (frequency of occurrence, percent abundance, biomass, and energy content).
  • Tells you how dependant a predator is on a specific prey.
124
Q

How can we study food webs using fatty acid analysis?

A
  • Comprise the majority of lipids among organisms
  • Prey lipids are consumed by a predator and deposited into
    adipose tissue with little modification or in a predictable pattern
125
Q

How can we study food webs using stomach content DNA?

A
  • Metabarcode sequencing of prey items from degraded stomach contents
  • Enhances diet data and has the capacity to reduce inefficiencies caused by unidentifiable samples
  • Must have a prey library
126
Q

3 ways contaminants (mercury, PCBs, PBDEs) get into the arctic, and what’s the main driver?

A
  1. Ocean currents
  2. Rivers
  3. Wind ** major

Slower degradation in cold areas.

127
Q

How does the wind bring contaminants into the arctic?

A
  • Contaminants evaporate in warmer temperatures and are moved by winds to colder places
  • In cold temperatures, the contaminants condense and fall to earth.
  • Stored in fats (organochlorines) and in skin and muscle (lead, mercury, heavy metals).
128
Q

T or F - Ocean currents bring most contaminants to the arctic.

A

False - wind currents do.

129
Q

Where are these contaminants stored?

  • Organochlorines
A

Fat

130
Q

Where are these contaminants stored?

  • Heavy metals (lead, mercury)
A

Skin and muscle

131
Q

Bioaccumulation

A

the process by which chemicals are taken up and retained by organisms from their environment and diet

132
Q

the process by which chemicals are taken up and retained by organisms from their environment and diet

A

Bioaccumulation

133
Q

Biomagnification

A

contaminants persist in fat, magnifies up food chain

134
Q

contaminants persist in fat, magnifies up food chain

A

Biomagnification

135
Q

T or F - levees of organochlorines (PCB and HCH) are found in very high concentrations in polar bears, especially in North America.

A

False - found in very high concentrations everywhere, but much higher in Europe/Russia compared to Canada.

136
Q

T or F - Polar bear mothers that lost cubs had much higher concentrations of pollution.

A

True

137
Q

Arctic ecosystem characterized by:

1) Seasonal periodicity of insolation
2) Extreme seasonality of sea ice extent

How have animals adapted to these characteristics (1 main way)?

A

Forage intensively during peak primary production (summer and fall):
• Build energy (i.e. lipid) stores
• When resource productivity is lower (winter), use lipid stores as energy

138
Q

T or F - sea ice decline in all months has been observed since 1980.

A

True

139
Q

T or F - ice decline in the arctic has been steady since 1980, but a huge decline occurred in 1995 onwards.

A

True

140
Q

How has warming changed arctic habit and species?

A

Significant changes to habitat
• Longer open water period

Northward migration of subarctic species in summer
• Harp seals, killer whales, Capelin and Sand Lance

Causing a decrease in Arctic biota:

1) Abundance and distribution
2) Growth and condition

141
Q

T or F - Bowheads have increased in body condition due to global warming.

A

True - but more losers than winners.

142
Q

T or F - many areas in the arctic have experienced water temp changes of more than +2C.

A

True - resulting in an expansion of Atlantic water and decline in arctic water (and fish are following the warmer temperatures).

143
Q

T or F - Atlantic water is contracting, while arctic waters are expanding.

A

False - opposite

144
Q

T or F - Arctic systems now have less feeding links.

A

False - they have more feeding links because the arctic is becoming borealized.

145
Q

T or F - the arctic is increasing in boreal characteristic (increasing number of species, links, connectance).

A

True

146
Q

T or F - we are seeing an increase in southern associated species with a concomitant decline of northern-associated species.

A

True

147
Q

T or F - Ring seals are travelling less and staying in smaller areas due to ice loss.

A

False - travelling larger distances and spending more time offshore to feed due to ice loss. Using more energy to gain resources.

148
Q

Ringed seal response to ice loss.

A
  • Travelling larger distances and spending more time offshore to feed due to ice loss. Using more energy to gain resources.
  • Central place foragers (depths to surface) but now:
  • Less time hauled out on ice (resting), more time diving.
  • Diving to deeper depths and for longer durations over both habitats (continental shelf and arctic basin)
  • Ringed seals now spend more time closer to glaciers to hunt arctic cod
149
Q

Glaciers are productive zones that many animals stay near to feed. How have belugas responded to this?

A
  • Ringed seals now spend more time closer to glaciers to hunt arctic cod
  • Belugas spend significantly less time close to glaciers now, possibly shifted diet to more boreal species like capelin and herring (found further offshore)
150
Q

How have polar bear diets/health changed in Greenland?

A
  • Periods with warmer temperatures and less sea ice were associated with more subarctic and less arctic seal species consumption
  • Are more hooded seals (further offshore, more temperate species) and less ringed seal

• Can affect contaminant transfer

151
Q

The Canadian arctic has experienced a summer sea surface temperature increase of __C in 30 years.

A

3.5

152
Q

The Canadian arctic has experienced a sea ice loss of __% in less than 30 years.

A

15

153
Q

T or F - Transient species have higher contaminant loads and being transported to Arctic species when consumed, compared to resident arctic species.

A

True.

154
Q

T or F - in Cumberland sound, organisms are attaining a higher proportion of carbon from fish sources over time.

A

False - more carbon from phytoplankton energy BUT many species eating more forage fish (instead of larger fish)

155
Q

T or F - in Cumberland sound, both ringed seals and belugas are consuming much more forage fish (cod, capelin) compared to larger fish (ex. Greenland halibut)

A

True

156
Q

Which of these is false?

In regards to Cumberland sound:

a. There has been a reduction in diversity of basal resources
b. Species are packing closer together (increased density)
c. Community niche space has increased
d. Reduction in trophic position
e. Increased trophic redundancy

A

c. Community niche space has increased

It has decreased in total area.

157
Q

In ringed seal feeding behaviour, are diets different in adults vs juveniles? Does this vary by area?

A

Yes - adults consume more forage fish (highest in resolute bay, more trophic omnivory at lower latitudes).

Subadults consume more zooplankton.

158
Q

T or F - Trophic omnivory in ringed seals is highest at higher latitudes (e.g. Resolute bay).

A

False - it’s lowest in Resolute bay and higher at lower latitudes.

159
Q

T or F - trophic omnivory in ringed seals does not change trophic level position.

A

False - it lowers it.

160
Q

In which of these habitats did Ringed seals have the highest total niche width?

a. Beaufort Sea
b. Resolute Bay
c. Hudson’s Bay
d. Ulukhaktok
e. Baffin Bay

A

d. Ulukhaktok

161
Q

T or F - Broader niche size is found at lower latitudes.

A

True

162
Q

T or F - Both belugas and ringed seals are generalists.

A

False - Belugas are but ringed seals are individual specialists.

163
Q

T or F - Total niche width increases with decreasing latitude.

A

True

164
Q

T or F - The degree of individual specialization increases with latitude.

A

False - it doesn’t change with latitude.

165
Q

Is predation a direct or indirect effect?

A

Predation: one species directly affects another

166
Q

T or F - Shorebird nest predation rates decrease with increasing latitude.

A

True - benefit of migrating.

Some other birds (Thick billed murres) nest on cliffs for this reason, and Eiders breed on small islands where they are protected from foxes.

167
Q

Briefly describe the ecology of fear.

A

Non-consumptive predator effects
• Trait-mediated indirect effect
• Altered foraging patterns
• Chronic stress under risk of predation

168
Q

Most common indirect effect between 2 species?

A

Competition between predators for same prey

2 competitors negatively affect each other

169
Q

Interference competition

A

Competition between predators are direct – such as aggression

170
Q

Competition between predators are direct – such as aggression

A

Interference competition

171
Q

Two species that share a predator also negatively affect each other
Increases in one prey benefit the predator, the predator population grows and increases predation pressure on the second prey

A

Apparent competition

172
Q

Apparent competition

A

Two species that share a predator also negatively affect each other
Increases in one prey benefit the predator, the predator population grows and increases predation pressure on the second prey

  • Moose increase = wolves increase, but wolves also eat caribou
173
Q

Intraguild predation

A

Incorporates both direct and indirect effects - Combines both predation and competition between
predator species of the same ‘guild’.

  • Predator (IGpredator) preys upon another predator (IGprey) with both competing for same shared resource
  • Pressure modulated by resource availability (decrease intraguild predation pressure due to large amount of resources, or increases due to lack of resources).
174
Q

Predator preys upon another predator with both competing for same shared resource
- Pressure modulated by resource availability (decrease predation pressure due to large amount of resources, or increases due to lack of resources).

A

Intraguild predation

175
Q

Describe the changes seen in cod/capelin, halibut, and belugas with changing intraguild predation. What is a term for this?

A
  • Decreasing population of top predator, increases (i.e. releases) population of prey (halibut)
  • Called mesopredator release
  • In 1980-2000: Beluga more reliant on IG predate (halibut) and hardly on cod/capelin.
  • In 200-2010: Beluga eating less halibut, more cod/capelin (decreases pressure on halibut)
176
Q

Mesopredator release

A

Decreasing population of top predator, increases (i.e. releases) population of prey

177
Q

Decreasing population of top predator, increases (i.e. releases) population of prey

A

Mesopredator release

178
Q

List 3 (general) levels that will be affected by intraguild predation.

A
  1. Individual level effects
  2. Population level
  3. Community level
179
Q

*not vital

How does intraguild predation change things at the individual level?

A

a) Behavioural - escape behavior, young killifish
b) Morphology - body size with ontogeny – larger forage on smaller
c) Chemical – develop toxins as adults - salamander
d) Fitness - enhanced growth – more energy-rich prey
e) Life-History – brood size, growth rate, lifespan

180
Q

*not vital

How does intraguild predation change things at the population level?

A

a) Size – mesopredator release – beluga and halibut
b) Stability – impact alternative stable states
c) Resilience – impact alternative stable states

181
Q

*not vital

How does intraguild predation change things at the community level?

A

a) Guild structure – trophic group
b) Community diversity – diversity of system
c) Community stability - impact alternative stable states
d) Food web structure – impact topology and interactions strengths

182
Q

What prevents species from dispersing globally? Does it vary?

A

Geographic Barriers:

  • Oceans
  • Mountains
  • Deserts
  • Large Lakes

Barriers are in the eye of the beholder: what is a barrier for one species is not a barrier to another

  • mountains may restrict plant distributions, but not birds
  • sea ice is a barrier for killer whales, but not Red foxes
183
Q

What is the significance of Alfred Russel Wallace’s 6 global diversity realms?

A
  • Recent studies still find it pretty accurate
  • Evolutionary uniqueness in each of these different areas (neoarctic, neotropical, Ethiopian, palaearctic, oriental, Australasian)
  • More distinctness in the Southern Hemisphere (deceased dispersal potential and climatic stability)
  • Less Barries, less connectivity, less stable in the north
184
Q

T or F - There are more dispersal barriers in north, arctic communities than in south, tropical/temperate ones.

A

False - opposite

185
Q

Species introduced to regions outside of their historic native range

A

Invasive Species

  • implies they’re an exotic species and a threat to native species
186
Q

Invasive Species

A

Species introduced to regions outside of their historic native range
* implies they’re an exotic species and a threat to native species

187
Q

How much are invasive species being spread and how?

A

Species are being transported across barriers at an increasing rate owing to human movement and commerce

  • 50,000 times greater rate of spread than by natural dispersal in some cases
  • major vectors are planes, ships and humans
188
Q

Exotic Species

A

from another part of the world

189
Q

from another part of the world

a. Introduced species
b. Alien species
c. Exotic species
d. Invasive species

A

Exotic Species

190
Q

implies introduction but not a threat

a. Introduced species
b. Alien species
c. Exotic species
d. Invasive species

A

Introduced Species

191
Q

implies introduction to a particular ecosystem

a. Introduced species
b. Alien species
c. Exotic species
d. Invasive species

A

Alien species

192
Q

Introduced Species

A

implies introduction but not a threat

193
Q

Alien species

A

implies introduction to a particular ecosystem

194
Q

Describe the classical model of invasion (the process)

A
  • Biogeographic filter: Dispersal barrier (prevents many species from entering a new area, like an ocean)
  • Physiological filter: Fundamental nice prevents organisms from colonizing (abiotic factors)
  • Biotic filter: Realized niche prevents them from colonizing (competition, predation)

At each level, species are being filtered out, so from an initial start of 10 species, only 2-3 might make it through.

Establishment requires dispersal across barriers, colonization in acceptable number, and successful reproduction

195
Q

How does the human mediated invasion model differ from the classical model?

A

Classical:

  • Biogeographic filter: Dispersal barrier (prevents many species from entering a new area, like an ocean)
  • Physiological filter: Fundamental nice prevents organisms from colonizing (abiotic factors)
  • Biotic filter: Realized niche prevents them from colonizing (competition, predation)
  • Many species filtered out.

With human activity, species may skip over the biographic filter due to human interactions, now less filtered out physiologically and bionically… instead of 2-3 potential established species, now 5 can establish.

196
Q

European starlings were introduced in NY in 190 and very quickly colonized and dispersed throughout North America and boreal zone. Crested mynah’s were brought to Vancouver from Hong Kong - what was their response?

A
  • Did not spread outside of Vancouver (and the last 2 left there died in 2003)
  • Failed to adapt to local climate (incubation strategy)
197
Q

What allows invaders to invade? Why do only some survive and establish self sustaining populations?

What 2 main reasons allow invaders to invade?

A
  1. Broad Environmental Tolerance (large fundamental nice)
    - posses life history traits that confer superior colonizing ability or ability to acclimate to a wide range of habitats
  2. Local Adaptation
    - readily adapt to local selective pressures
198
Q

Invasive plants seem to be more virulent in introduced habitats compared to their native habitats

Introduced plants, released from herbivory, reallocate resources
from defense mechanisms into growth and development

A

Increased Competitive Ability Hypothesis

199
Q

Increased Competitive Ability Hypothesis (for invasive species)

A
  • Invasive plants seem to be more virulent in introduced habitats compared to their native habitats
  • Introduced plants, released from herbivory, reallocate resources
    from defence mechanisms into growth and development
    • Lower herbivory rates
    • evolve to grow taller, produce more biomass, and yield more viable offspring than their native counterparts
    • Greater fitness

ex. Purple loosestrife was introduced from Europe to NA and now threatens wetlands of western Canada due to their ability to produce more biomass (grow taller)

200
Q
  • Species in their native range are suppressed by natural enemies (realized niche)
  • Alien species arrive to a new area, without the grazers, insect pests, diseases, parasites, etc. of their native range – their “enemies”
  • Hence, alien species “escapes” from their enemies and are no longer affected by biotic constraints
  • Thus, alien growth and success is much greater in new range
A

“Enemy release” hypothesis i.e., escape from biotic constraints hypothesis

201
Q

“Enemy release” hypothesis i.e., escape from biotic constraints hypothesis (for invasive species)

A
  • Species in their native range are suppressed by natural enemies (realized niche)
  • Alien species arrive to a new area, without the grazers, insect pests, diseases, parasites, etc. of their native range – their “enemies”
  • Hence, alien species “escapes” from their enemies and are no longer affected by biotic constraints
  • Thus, alien growth and success is much greater in new range

Ex. White campion flower is more damaging in it’s native range (Europe) than invaded NA - probably due to biblical control (controlling pests with other organisms)

202
Q

The enemy release hypothesis for establishment of invasive species states that alien species “escape” from local enemies and so are no longer affected by biotic constraints.

Does this mean that they have no potential enemies in the new range?

A

It depends:

• Are potential enemies generalists or specialists?
• Are population sizes of potential enemies large or
small? (large = increase predation pressure)
• Do potential enemies feed on foliage or seeds? (seeds have a larger impact on fitness)
• Are there similar hosts for potential enemies in new area?

203
Q

Biodiversity hypothesis (establishment of invasive species)

A
  • High biodiversity 􏰁 high community stability
  • Stable communities not invaded

• Uses niche concepts:

  • Different species have different niches
  • As number of species increases, the filling of niche space increases too
  • Thus highly diverse communities are more difficult to invade
204
Q
  • High biodiversity 􏰁 high community stability

* Stable communities not invaded

A

Biodiversity hypothesis (establishment of invasive species)

205
Q

Paradox of invasion

A

Paradox of invasion: positive relationship between invader and native diversity at large scales, but negative relationship at smaller scale

(Low native diversity can reduce possibility for invasive, and more native diversity can also increase invasive species).

  • Within a cluster, high native species diversity allows little room for invasive niches – negative relationship = less invasible/vulnerable
  • At larger scale, factor that promote diversity also promote more invasibility = more vulnerable
206
Q

positive relationship between invader and native diversity at large scales, but negative relationship at smaller scale

A

Paradox of invasion

207
Q

T or F - High native diversity can increase the number of invasive species that can establish, when looking at a large scale ecosystem.

A

True - Paradox of invasion

  • Within a cluster, high native species diversity allows little room for invasive niches – negative relationship = less invasible/vulnerable
  • At larger scale, factor that promote diversity also promote more invasibility = more vulnerable
208
Q

T or F - Low native diversity can increase the number of invasive species that can establish.

A

False - Paradox of invasion. Usually lower invasive at low numbers of native species (high invasive at high numbers of natives).

209
Q

T or F - High native diversity can increase the number of invasive species that can establish, when looking at clusters of populations.

A

False - only at large scales.

  • Within a cluster, high native species diversity allows little room for invasive niches – negative relationship = less invasible/vulnerable
  • At larger scale, factor that promote diversity also promote more invasibility = more vulnerable
210
Q

T or F - Native species diversity generally decreases with increasing latitude.

A

True.

211
Q

T or F - Native species diversity generally decreases with increasing latitude, which gives non natives more opportunity to establish.

A

False - but little research done. Usually low numbers of natives means low numbers of invasives.

212
Q

There is little understanding of the status of invasive species in the boreal forest.
Why?

A
  • Extreme climate, low biodiversity, and poor resource availability are hostile to introduced species
  • Much of the forest remains undisturbed, reducing susceptibility to exotics
  • Researchers aren’t looking
213
Q

How many non-native species have colonized Canada’s boreal forests in the past 500 years? What are they mostly?

A

At least 1180 non-native species have colonized.

Mostly Plants, insects, earthworms, slugs, pathogens

214
Q

T or F - Almost 60% of non-native species in Canada were intentionally introduced, most of which are insects and plants.

A

True - 58%.

215
Q

T or F - Deliberately or accidentally introduced vascular plants are the most common (by species) invasive in Canada.

A

False - insects are at >480 species, but plants are second highest at 300+

216
Q

How did invasive species unintentionally reach Canada? Particularly insects, which are the most common by species number.

A
  • in ballast (soil and litter) from early sailing ships
  • in dung and on fur of domestic animals
  • introduction via stems, foliage, and root balls of ornamental trees and shrubs
  • introduction of bedding plants and forage crops via seed
  • hitchhiking of adult and immature insects and other microorganisms in airplanes and ships
  • in association with untreated solid wood packing materials
217
Q

Why were some invasive deliberately introduced to Canada?

A
  • for commercial silk production
  • as ornamentals
  • as forage or food crops
  • for research
  • for biological control
  • for improving soil conditions (e.g., earthworms)
218
Q

Main cause of invasive species is ____.

A

humans!

219
Q

T or F - Most invasives (especially forest insects) are expected to reach Canada through international shipping practices.

A

False - Highest predicted future entry rates of non-native forest insects:

large urban areas, major border crossings, and the transportation crossroads and major checkpoints on major northern highways

220
Q

At which conditions will introduced species be most likely to establish?

A

Exotic species richness is relatively higher with greater anthropogenic disturbance

• agricultural fields, forestry cut blocks & oil sands

221
Q

T or F - Exotic species richness is relatively lower with greater anthropogenic disturbance.

A

False - it’s higher.

222
Q

T or F - Invasive species are least likely to establish when the native species are at intermediate species richness.

A

True - intermediate disturbance hypothesis applies

223
Q

The likelihood of non natives establishing and expanding its geographic range.

Incorporates:

  • Number of introduction events
  • Absolute # of individuals in a release event
  • Number of discrete release events
A

Propagule pressure

224
Q

Propagule pressure

A

The likelihood of non natives establishing and expanding its geographic range.

Incorporates:

  • Number of introduction events (“introduction effort”)
  • Absolute # of individuals in a release event (propagule size)
  • Number of discrete release events (propane number)

• As number of releases and/or the number of individuals released increases, propagule pressure also increases

Propagule pressure will increase the likelihood of establishing a non-native population and of this population expanding its geographical range - If we reduce propagule pressure, we reduce risk of alien species becoming established.

225
Q

Colonization pressure

A
  • With more invasive species introduced, more invasions are expected
  • We’ve seen exponential increases in invasive species in Canada
  • Related to propagule pressure but refers to number of species introduced
  • Also looks at probability of establishment
226
Q

With more invasive species introduced, more invasions are expected

A

Colonization pressure

227
Q

T or F - With more invasive species introduced, more invasions are expected.

A

True - Colonization pressure.

228
Q

What is the greatest threat to the biodiversity and structure of native zooplankton communities on the Canadian Shield since acid rain?

A

Spiny water flea

- Caused 20% loss of species richness

229
Q

T or F - the spiny water flea caused a 5% loss in species richness (zooplankton) since it was established on the Canadian shield.

A

False - it caused 20% loss in species richness.

230
Q

What type of invaders were most common historically vs currently?

a. Fish
b. Algae
c. Plants
d. Inverts
e. Mammals

A

Historically: Plants

Currently: Inverts

231
Q

___ are implicated in 75% of non native species invasions since 1959.

A

Ships

232
Q

How do ships increase the spread of invasive species?

A
  • Ballast water
  • Ships loaded with cargo are stable and do not need ballast water
  • Ships without cargo carry ballast water to increase stability
  • Probably the single biggest source of invasive species globally (combined with hull fouling species)

Many invasive that came to the Great Lakes came from Europe, through ballast water (ex. zebra mussel)

233
Q

Where is most ballast water discharged in the arctic? Is this considered safe due to the temperatures?

A

Most ballast water discharge in Churchill – highest risk, also has warmer temperatures.

Number of non-indigenous species increasing over time
Propagule pressure – more shipping, more ballast water exchange, more potential

234
Q

What (phyla) of non native species are being established most commonly in arctic waters?

A
  • Arthropoda: insects, arachnids, myriapods, and crustaceans
  • Algae are also establishing in high numbers (Ochrophyta)
235
Q

What can be done to control invasive species arriving in Canada via ships?

A

Provincial, federal & international cooperation
• Strategies address the threat of aquatic
and terrestrial invasive species
• Ballast water regulations: ocean-going
vessels flush their tanks with salt water
before entering freshwater systems
• Since 2006 when the laws were passed, no
new aquatic invasive species has been found in the Great Lakes

236
Q

How do rats (invasive species) influence seabird and nitrogen abundance?

  • Hinted for exam
A

In Chagos Archipegalo, uninibatied by humans for >40 years, no fishing, pristine conditions.

  • Black rats introduced in late 18th century, but were only invasive on some islands (predate on bird eggs and chicks).
  • Seabirds feed at sea and transfer marine energy to land.

Seabird densities and nitrogen deposition rates were 760 and 251 times higher, respectively, on islands where humans have not introduced rats.

  • Nitrogen is expected to leach off islands to nearshore marine environments through rainfall and coastal advection
  • Leads to an increase in coral reef productivity!

Damselfish inhabiting reef crest grew faster near islands without rats
Reef communities also had more biomass near islands without rats
- Everything increased in biomass on rat tree islands

**key: No rats = increased seabirds which impacts all other growth, even increases biomass in the ocean due to the nitrogen input

237
Q

T or F - There have been more introductions of invasive species in north (Atlantic Ocean) region of the arctic, around Iceland and Norway, vs in Canada and the US.

A

True.

238
Q

T or F - Fishing (without ballast water dumping) doesn’t significantly increase the number of invasive species that establish.

A

False - fishing does increase it, but so does ballast water dumping.

239
Q

Without human introduced rats on the Chagos Archipelago, seabird density increased by ___x and nitrogen deposition increased by ___x.

A

Seabird density - 760x higher

Nitrogen deposition - 251x higher

240
Q

T or F - The Arctic is warming even faster than the global average, about ~4x faster.

A

False - 2x faster.

241
Q

T or F - Sea ice loss is greatest in Cumberland sound.

A

False - greatest in Bering Sea.

242
Q

Does sea ice loss positively feedback?

A

• sea-ice loss amplifies
warming
• feedback from declining surface albedo
• Several rapid direct and indirect responses to warming

243
Q

T or F - live green vegetation is increasing in the arctic. If so, why? If not, why not?

A
  • True, increase in shrubs and other vegetation.
  • Due to longer growing season.

Used normalized Difference Vegetation Index (NDVI)
• Live green vegetation detected by remote sensing has increased

244
Q

T or F - the longer growing season in the arctic has increased plant productivity and marine productivity.

A

True - phytoplankton production has increased.

245
Q

T or F - Arctic waters are becoming more benthic.

A

False - becoming more pelagic.

246
Q

How does the reduction of benthic prey populations affect other animals?

A
  • Becoming more pelagic
  • Decrease in benthic fauna and along with it, benthic feeders
  • Affects grey whales, walrus, and sea ducks
247
Q

How are ringed seals affected by arctic warming (ex. rain instead of snow)?

A

Rain collapses ringed seal birth lairs, exposing pups to predators and hypothermia.

248
Q

Describe winners and losers in the arctic with global warming, using bowhead whales, ringed seals and belugas.

A

Winners:
- Bowhead: increased body condition over time due to increase in phyto and zooplankton.

Losers:
- Ringed seal and beluga body condition decreased due to reduction in cod and other food.

249
Q

How are terrestrial animals like reindeer affected by arctic warming (ex. rain instead of snow)?

A

Access to forage can be greatly restricted by snow, which may become icy, hard, and impenetrable on the tundra. Under such conditions Svalbard reindeer are confined to forage in small, snow-free patches.

With warming: Substantial ablation associated with winter warming has resulted in reduced mortality, increased fecundity, and increased abundance of Svalbard reindeer (a winner).

250
Q

T or F - Global warming benefits Svaldbar reindeer, bowhead whales, and belugas.

A

False - benefits first 2 but not belugas.

251
Q

dimictic + example

A

Boreal lakes are thermally stratified in summer and winter, but mix in spring and fall (mixed twice = dimictic)

252
Q

Boreal lakes are thermally stratified in summer and winter, but mix in spring and fall (mixing twice = ___)

A

dimictic

253
Q

How does global warming affect lake stratification?

A
  • Boreal lakes are thermally stratified in summer and winter, but mix in spring and fall
  • Many Arctic lakes only stratify in winter
    • constant mixing in summer
  • Increased temperatures can
    cause summer stratification
254
Q

Monomictic + example

A
  • Many Arctic lakes only stratify in winter

• constant mixing in summer

255
Q

Cold monomixis

A

Colder lakes that stratify only under winter ice cover and mix the remainder of the year

256
Q

Colder lakes that stratify only under winter ice cover and mix the remainder of the year = _____

A

Cold monomixis

257
Q

How is increased lake stratification a positive effect?

A

• positive feedbacks via warming of the surface layer
• smaller volume of water above thermocline
• possible increases in phytoplankton and zooplankton growth rates
• increased propensity to deep water oxygen
depletion
• increased retention of contaminants within Arctic food webs

258
Q

What is the primary productivity response to global warming in terms of lakes with fish vs lakes without?

A

Productivity higher in lakes with fish than without.

259
Q

How are winter moth outbreaks increasing in Sweden due to warming?

A

Range expansion of animals

• Winter moth outbreaks in Sweden - severely defoliated forests and affects carbon sequestration

260
Q

T or F - red foxes are displacing arctic foxes in the arctic.

A

True

261
Q

Beavers are expanding their range due to global warming - what are the effects? Why is this occurring?

A
  • Expanding to tundra (above tree line)
  • Changing FW flow and nutrient flow
  • Attributed to increase in woody vegetation
  • Alter the stream hydrologic regime, which alters freshwater physical habitat, biotic composition, and habitat connectivity
  • Pond formation increases winter water temperatures in the pond and downstream, likely creating new and more varied aquatic habitat
262
Q

Phenology

A

Timing of events (ex. sea ice changes throughout the year)

263
Q

Timing of events (ex. sea ice changes throughout the year)

A

Phenology

264
Q

How is phenology changing with global warming?

A

Life-cycles of plants and animals have been affected
- Temperatures affect plants’ growing season, flowering time and timing of pollination by insects

  • Studies already showing:
    • in temperate zones – flowering time occurring earlier in the season
    • over past two decades the growing season increased by 18 days in Eurasia and 12 days in N. America
  • Many birds time their nesting so that eggs hatch when insects are available to feed nestlings.
  • In turn, insect emergence is often synchronized with leafing out in their host plants.
265
Q

Which of these events are now occurring earlier due to warming in the high arctic of Greenland?

  • onset of flowering (plants)
  • median date of emergence (arthropods)
  • clutch initiation dates (birds)
A

All of them!

266
Q

T or F - phenology patterns of animals (ex. reproductive timing in seabirds) is becoming increasingly unpredictable.

A

True

267
Q

Seabirds have not exhibited a shift in their laying date in relation to SST in waters around the breeding site in the three months preceding egg laying.

What happens if other organisms are shifting their reproductive times with global warming?

A
  • Suggests that if lower trophic levels are shifting in parallel with changing SST, seabirds, in general, may be at risk from increasing levels of trophic mismatch
  • Food availability mismatch between prey (i.e. zooplankton boom) and increased food availability for chicks
  • Impact populations or will they switch to other available prey items?

In highly seasonal environments, offspring production by vertebrates is timed to coincide with the annual peak of resource availability.

268
Q

T or F - seabirds have not exhibited a shift in egg laying dates in relation to sea surface temperature.

A

True

269
Q

T or F - In highly seasonal environments, offspring production by vertebrates is timed to coincide with the annual peak of resource availability.

A

True

270
Q

T or F - the growing season in the arctic has shift earlier, and the timing of caribou calving has too in response.

A

False - there’s an trophic mismatch.

Greater mismatch reduces production and survival of caribou calves

271
Q

trophic mismatch

A

peak demand for resources by reproductive females now much later than the peak resource availability

272
Q

peak demand for resources by reproductive females now much later than the peak resource availability

A

trophic mismatch

273
Q

How are increasing shrubs in the arctic positively feeding back?

A

Deeper snow packs, higher soil temperatures, promote increased microbial activity
• increases the availability of
nutrients, which shrubs can use more efficiently than other tundra plants.
Especially in areas with the most disturbance
• Disturbance & nutrient
availability are known to be closely related

274
Q

Where will the highest changes to boreal vegetation occur?

A

• Greatest change likely will
occur at the higher latitudes
• Northern Canada and Alaska are already experiencing rapid warming and reduction of ice
cover
• Vegetation existing in these areas will be replaced with temperate forest species
• Tundra, Taiga and Temperate forests will migrate pole ward
• Some plants will face extinction because habitat will become too small (e.g., mountain tops of European Alps)

275
Q

T or F - Alpine vegetation will change most dramatically in the boreal.

A

True - greater changes will likely occur at higher latitudes.

  • Replaced by temperature species
  • Plants will face extinction due to their range being too small
276
Q

T or F - Fire frequency will decrease in the boreal as temperate species increase their range (not pyrophytic)

A

False - it will increase

277
Q

T or F - There is more distinctness in the Southern Hemisphere. Explain why or why not.

A

True - decreased dispersal potential, climatic stability.

278
Q

T or F - Northern ecosystems are less stable. Explain why or why not.

A

True - less dispersion barriers, less connectivity, less stability.

0 - Boreal Ecology (4 decks)

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