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Boreal Ecology > 15 - Species Diversity > Flashcards

15 - Species Diversity Flashcards

1
Q

the number of species increases from ____ to ____ latitudes

A

high

low

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2
Q

low prey diversity promotes ____ population dynamics

A

unstable

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3
Q

less species redundancy ____ ecosystem resilience

A

lowers

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4
Q

more species redundancy _____ ecosystem resilience

A

increases

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5
Q

this latitudinal gradient includes what animals?

A

mammals, land birds, ants, butterflies, marine coastal fish, marine bivalves, copepods, snakes, almost universal

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6
Q

species richness may also vary with what other factors?

A

longitude, elevation, depth, topography, aridity

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7
Q

what hypotheses exist regarding the latitudinal gradient?

A 
history 
spatial heterogeneity
competition
predation
productivity
environmental stability
disturbance
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8
Q

describe the history/time hypothesis

Support?

Argument??

A

topical habitats are older TF more stable and less disturbed.
had time for adaptation and speciation

Support: geological past of boreal less constant that tropics. All communities diversity with time

Argument: as glaciers moved in, species moved south to escape. This hyp cannot be tested

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9
Q

describe the spatial heterogeneity hypothesis

A

higher diversity in tropics bc of increase in # of potential habitats

decrease in envr complexity moving away from equator

the more heterogenous and complex the physical envr, the more diverse the plant and animal communities

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10
Q

describe the competition hyp

A

less competition in boreal envr compared to tropics

northern pop regulated by extreme envr conditions, not biological factors. in tropics, pop’s increase to densities where comp for resources is necessary

sources of mortality are abiotic

high competition results in higher rates of speciation

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11
Q

alpha diversity

A

overall species richness

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12
Q

beta diversity

A

number of unique species in diff habitats

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13
Q

where is alpha and beta diversity highest why?

A

tropics

organisms more specialized to habitats

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14
Q

ex of competition leading to speciation?

A

darwin’s finches

comp for food led to specialized beak morphology (feeding specialization)

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15
Q

describe predation hypothesis

A

increase species in tropics in function of increased number of predators that regulate the prey species

decrease comp among prey species

allows co-existence of prey species and potential for new

stronger selective pressure on avoiding predation than becoming better competitors

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16
Q

describe the cropping principle

what hyp is this under?

A

predation increases diversity by reducing intraspecific competition among prey species

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17
Q

example of cropping principle

A

presence of herbivores creates more niches for plants

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18
Q

under cropping principle, what happens if predators are removed?

A

prey start competing –> one/few may dominate

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19
Q

two species competing for the same limiting resources cannot exist

What law??

A

Gause’s law of competitive exclusion

20
Q

effect on community disproportionate to their abundance

A

keystone predator

21
Q

describe cropping principle in lakes

A

top predators feed on zooplankton
if TP removed, community diversity decreases. Dominated by a few species of large grazing zooplankton

add fish, diversity of small zooplankton and their invert predators increase

22
Q

describe mesopredator release?

why hyp is this under?

A

apex predators affect diversity as well as abundance of lower trophic levels

predation hypothesis

23
Q

describe the productivity hyp

A

tropics support a greater number of species bc of more resources

*increased production leads to increased diversity

24
Q

what are the exceptions to the productivity hyp?

A

marshes

desert

25
Q

TF there is a correlation between productivity and vertebrate biodiversity

A

False

26
Q

environmental stability hypothesis

A

constant climate –> finer specialization and adaptations, shallower niches

don’t have to deal with such a large amount of envr changes

27
Q

disturbance hypothesis

A

if community disturbance freq is high –> local extinction –> decrease in species diversity

if very low –> competitive exclusion by dominant species –> decrease in species diversity

ECOLOGICAL TIME SCALE

intermediate disturbance will maximize diversity and lead to patches at local scale

28
Q

what are some limitations of all these hypotheses?

A

circular (based on the assumption of greater diversity in tropics), some no supported by sufficient evidence (no consistent correlation btwn species diversity and envr stability, productivity, physical heterogeneity

29
Q

role of ice-age extinctions

A

slow speciation and colonization after glaciations

30
Q

role of polar harshness

A

high extinction rates, slow population growth

31
Q

role of tropical climatic stability

A

low extinction rates allow specialization and speciation

32
Q

role of tropical productivity

A

greater evenness, narrow niches

33
Q

role of structural heterogeneity

A

finer niche subdivision, microclimate heterogeneity

34
Q

role of interspecific interactions

A

competition, predation, and mutualism promote specialization

35
Q

TF primitive species are not abundant in the arctic

A

F - they ARE particularly abundant

–> think about plants

36
Q

Rapoport’s rule

A

taxa have larger ranges in polar regions

37
Q

provide 2 examples of “super dominant” species that are generally plastic

A

willow

lemmings

38
Q

____ ____ is the environmental variable that best predicts plant diversity in the arctic

A

summer temperature

39
Q

in general, what is expected to happen with a warming climate?

A

species diversity should increase

40
Q

what species are most vulnerable?

A

those that are most abundant in the northernmost part of the tundra or polar deserts

best adapted to climate conditions of high arctic where more competitive species are absent

41
Q

TF/ southern limits of turn see less specialization among microhabitats

A

False, greater

42
Q

what determines the northern borders of the geographic distribution of most animals?

A

temperatures lower than the species-specific tolerance limits

43
Q

what determines the southern borders of the geographic distribution of terrestrial arctic animals

A

biotic factors –> competitors and natural enemies

44
Q

T/F high temps determine the southern border of terrestrial arctic animals

A

F

45
Q

why is biodiversity important in the arctic

A

there is little functional redundancy among species in the arctic and species redundancy enhances ecosystem resilience

46
Q

what are the two types of research?

A

fundamental research
- understand generally how the world works

applied research

  • solve problems
  • conservation/management and such
47
Q

why is northern research important

A

rate of change may be more important than its magnitude

science of change is easier to study in the arctic

Boreal Ecology (15 decks)

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