Chapter 3 Flashcards

1
Q

Species richness varies with

A

PLOC

Productivity
Latitude
Other physical & biological variables
Climate

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

Earth’s species may
disappear due to:
(there are 6)

A

Habitat destruction

Overharvesting (particularly marine species)

Invasive species

Eutrophication

Global Climate Change

Other Human Activities

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

Naeem et al. (1994) & Tilman and Downing
(1994)

A

Two studies that paved the way to understand the relationships between
biodiversity and ecosystem functioning.

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

effects of
biodiversity on four important ecosystem
functions: which are
“pinc”

A

Productivity
Invasibility
Nutrient use and nutrient retention
Community and ecosystem stability

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

Species richness had a strong, positive effect on

A

primary productivity

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

slide 19 not sure how to break up

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

Increasing species richness increases

A

biomass production in primary
producers.

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

question: Does higher species diversity lead to higher ecosystem
productivity?

A

For at least low-stature plant communities… YES!

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

A recent meta-analysis of 368 experiments found that manipulated primary
producers in a variety of ecosystems (i.e. terrestrial, freshwater, marine)
resulted in an increase in biomass when high plant species richness occurred.

But, some mathematical modeling has found that although the relationship is
positive,

A

it occurs at a decelerating rate. (diminishing returns)

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

Why might productivity increase with species richness?

A

two mech
Niche complementarity

Species selection

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

what is niche complementarity

A

When species differ in the way they
use limited resources.

If each species differs in their
niches, the use of resources within a
community becomes more efficient
and this can leader to higher
productivity.

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

what is species selection

A

Species Selection (a.k.a. sampling effect)

May lead to increased productivity with increased species richness if diverse
communities are more likely to contain more productive species that come to
dominate the community.

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

is the relationship between the extent of ecosystem
functioning and the degree of niche overlap between species npositive or negative ?

A

negative

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

Meta analyses

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

If species exhibit resource partitioning and niche complementarity, then

A

more diverse communities should use resources more efficiently and the
amount of unused resource in an ecosystem should decline as species
richness increases.

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

Most data in support of niche complementarity
comes from

A

terrestrial plants.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

nitrogen availability limits

A

primary productivity.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Nitrogen
in above ground vegetation also correlated

A

positively with species diversity.
This means N uptake increased with increasing plant diversity.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Dijkstra et al. (2007)
an
increase in plant species richness reduced

A

that an
increase in plant species richness reduced leaching loss of dissolved inorganic nitrogen.

20
Q

Cardinale et al. 2011
on polycultures

A

Found that species-rich polycultures reduced nutrient concentrations (mean
= 48%) more than monocultures

Little evidence that polycultures used resources more efficiently; standing
nutrient concentrations in soil/water were higher in polycultures than the
most efficient monocultures

21
Q

Do polycultures use resources more efficiently
than the most efficient monocultures?

A

They Uptake it, but do they use it efficiently?

Simple Answer: it depends on the complexity

homogenous vs heterogeneous

biomass plays a role

heterogeneous streams increased algal richness dramatically reduced the
amount of dissolved nitrogen.

by increasing algal species richness in heterogeneous streams, water quality
was significantly increased due to niche complementarity.

22
Q

Temporal Stability

A

Examines species abundance (usually measured in biomass) over time

Diversity had a strong, positive effect on the temporal stability of the total
plant community, but a negative effect on the stability of individual species
abundances.

23
Q

The idea that increased species diversity leads to ecosystem stability has been
around a long time!
but does it

A

The answer seems to rest on how we view
stability.

24
Q

Are more diverse communities more resistant to invasion by exotic species?

A

Overall, yes, but there are some important unanswered questions.
Elton (1958): “This resistance to newcomers can be observed in established
kinds of vegetation, due to competition for light and soil chemicals and
space.”

Fargione and Tilman (2005) – again using the Cedar Creek plots – found
both biomass and number of invading plants declined as richness of resident
plant community increased.

25
Increasing biodiversity negatively affects
invaders ability to survive
26
decreasing occupied space
decreases native species richness?
27
What traits make it more likely for species to go extinct?
strong, consistent effects of biodiversity loss on ecosystem functionality Loss of particular species can significantly impact ecosystem functioning (keystone species) Some traits such as population size, geographic range, body size, trophic level, low fecundity can accurately predict probability of loss for some species.
28
How has biodiversity been affected by human activities?
It seems species richness can stay the same, but species turnover has risen in areas of high human impact (i.e. invasive species taking over native species) - Thus, Beta diversity is high while Alpha diversity remains similar. Still need to better understand effects of species richness on ecosystem functioning
29
How do multiple interacting trophic levels impact biodiversity?
trophic-level interactions are important for ecosystem functioning alterations in the number & kinds of top-level consumers have cascading effects number of species declines as we move from lower to higher trophic levels, species extinctions tend to occur towards the top think pyramid
30
Why do areas of high native plant diversity also contain high numbers of invading plant species when experimental manipulations find the opposite?
Hypothesis to address this: Environmental factors that support high native plant diversity also support high exotic plant diversity. Small-scale experiments seek to control environmental variation.
31
Experimental evidence overwhelming finds that biodiversity alterations significantly impact ecosystem functioning, but some have questioned if that impact in natural ecosystems is significant.
Here again we are seeing the pull between experimental data and what actually occurs in natural systems.
32
Species richness varies with
Latitude Climate Productivity Other physical & biological variables
33
what was biomass a measure of
productivity
34
Tilman and Downing (1994)
Showed a link between species richness, ecosystem productivity, and ecosystem stability Found that plots with high plant species diversity were better buffered against the effects of a severe drought.
35
four important ecosystem functions:
Productivity Nutrient use and nutrient retention Community and ecosystem stability Invasibility
36
‘Jena Biodiversity Experiment’
study above- and belowground productivity and nutrient use efficiency.
37
Species richness had a strong, ------ effect on primary producers
positive
38
Cedar Creek productivity (measured in biomass) increased rapidly in response to the addition of a few plant species, but then
slowed (reached diminishing returns).
39
Positive effect of species richness on plant biomass....
increased over time.
40
how does increasing species richness affect biomass production in primary producers
Increasing species richness increases biomass production in primary producers. the relationship is positive, it occurs at a decelerating rate. (diminishing returns)
40
richness-biomass relationship, and functional group richness-biomass relationship have _______ correlations
Positive
41
Two mechanisms productivity increase with species richness?
Niche complementarity Species selection
42
Niche complementarity
If each species differs in their niches, the use of resources within a community becomes more efficient and this can leader to higher productivity.
43
Species Selection (a.k.a. sampling effect)
May lead to increased productivity with increased species richness if diverse communities are more likely to contain more productive species that come to dominate the community.
44
Transgressive overyielding
plots containing species mixtures yield more biomass than any monoculture plot.
45
when does species selection tend to be dominant vs ncihe complementarity
Studies of terrestrial plant communities suggest that species selection effects are the dominant drivers of ecosystem functioning EARLY in experiments Niche complementarity effects become stronger as communities mature.
45