4-5

Question 1

Patterns causes and consequences of biodiversity

Answer 1

patterns can be hard to find at small geographic scale
Productivity vs species diversity @different spatial scales

@a broad spatial scale the pattern is broad but decelerating

Question 2

Decreasing limb (4 factors)

Answer 2

1. shift from nutrient limitation to light limitation for primary producers
2. Intermediate productivity environments are more common (more species are evolved for them)
3. Higher productivity magnifies the impact of apparent competition (less species richness)
4. Communities exist at alternative stable states ( the sum of these stable states is greater)

Question 3

Higher productivity magnifies the impact of apparent competition (less species richness)
Demonstrated in:
Bacteria study to replicate species diversity at different productivity

Answer 3

A species has three main morphotypes (phenotypes) they then multiply into more morphotypes

• There’s the smooth (broth phase)
• fuzzy spreader (walls +bottom of spreader)
• Wrinkly spreader (air broth interphase)

-created a humped shape:
-At the being each increased +
smooth broth makes mat @ surface
- Wrinkle spreader takes over

Question 4

Communities exist at alternative stable states ( the sum of these stable states is greater)

Explain this concept in dynamic stable states
and static stable

Answer 4

1. Dynamic stable state:
   -ball able to shift back and forth
   - high resilience due to high perturbation (quick but temporary change) in @ species level
   - the ability of an ecosystem to return to its original state after a minor disturbance
   ex. tidal changes habitat species stay

Static stable state:
- Shift in environment factors that influence community structure (can’t shift back)
ex. acid in ocean increase on coral

Question 5

We observe higher diversity in …. areas.
Why is that the case?

Answer 5

Larger

1. larger areas=more habitat=more variety
2. Demographic processes:
   - A bigger area can support larger pop and lower extinction risk

Question 6

Island immigration and emigration

Answer 6

As the # of species on the island go up, the rate of imgration goes down

as the # of species on the island go up, the # of individuals per species goes down

Smaller pops are more likely to go extinct

Question 7

Experimental islands in Florida
What was the study
What were the results

Answer 7

100 small mangrove rhizaphoria
Measured initial area area of decrease in size and distance from island

Survied initial diversity of terrestrial anthropods then after size was reduced

Question 8

Species diversity= species… +species….

Answer 8

Richness
abundance

Question 9

What are the 6 main mass exstinctions

Answer 9

1. Ordovician- 445 mya 85% dead-rapid cooling
2. Devonian- 3340 mya-70% dead by astroid
3. Permian-250mya- 96% dead by volcanic eruption (biggest)
4. tirassic-200mya 76% dead
5. Cretaceous- 65mya -80%-asteroid+volcano
6. Anthropocene- now- 50% dead since last extinction

Question 10

Species in trouble

Answer 10

Evaluated by IUCN

Red list
- Extinct in wild
- Critically endangered
- Vulnerable
-Least concerned or near threaten
data deficient

-Amphibians!!
Most species threatened by equator

Question 11

Ecosystem productivity and stability:
Drought resistance in Cedar creek

Answer 11

Cedar creek accidentally measured this
during a drought
Better chance of survival= more diversity (15+ plants)
More species (higher biomass)= higher survival rate

Question 12

Protecting the ocean

Answer 12

Massive oceanic protection isn’t feasible

we need to protect areas and corridors

Question 13

Cedar creek

Answer 13

168 plots varying species richness
random grouping
- 1 to 18 species
measured productivity nutrient dynamic and stability for 15 years

Question 14

Ecotron (controlled environment facility)

Answer 14

• 14 domes
  3 levels of biodiversity w all trophic levels
  -Meseared:
  1. comunity respiration
  2. decomposition
  3. nutrient retention
  4. plant productivity
  5. water retention

Trophic leveles:
parasitoid herbivores anual plants decomposers

Findings ^ diversity communities consumed more co2
^diversity= ^ productivity

Question 15

Biodepth

Answer 15

Very similar but repeated across 7 countries
varying native species
factors in environmental reg
as you increase diversity you increase above ground plant biomass (higher rate over time)

Question 16

Jena

Answer 16

Below ground biomes and planted on many trophic levels

Question 17

Niche complementarity
and Species selection

Answer 17

Uses available resources and space most efficiently
highly productivity and complementarity effects through bacterial interaction
ex. nitrogen fixing plants - increase growth rate of other plants around

• use same resource differently so it can be maximized

2. Species selection
   a. Most productive species
   One species takes advantage

Question 18

Polyculture=……monoculture biomass in all primary producers

Answer 18

1.4

Question 19

Species selection sampling effect

Answer 19

One highly productive species becomes dominant (has higher productivity)
- Over time species richness/biomass relationship gets stronger slope because of the net effect of birth

Question 20

Nutrient use and retention
algee hetero (multiple habitat types) vs homo (one)

Answer 20

Effective resource partitioning leads to niche complementarity and high species richness.
^ species richness leads to
Low N available in soil
^ N uptake
Low N leaching

ex. stream algae @ varying species richness in 2 habitats (homo vs hetero)
-heterogenous habitat = positive correlation with species # and NO2 and biomass
polyculture did better than monoculture

Homogenous habitat still had a + relationship but was less strong

Question 21

Community and ecosystem stability

Answer 21

High species richness creates a good buffer to extinctions, invasive species and environmental change

Question 22

formula for species stability

Answer 22

Species stability= mean abundance/time

Community stability= abundance / squ variance+ covariance

Question 23

What bias does this formula hold?
Community stability= abundance / squ variance+ covariance

Answer 23

Bias towards species interaction
because of this, some argue that we should focus on individual species response to environmental fluctuation
- more diverse responses= better chances of positive result

ex. salmon and portfolio effect (diverse life history)

Question 24

Invasibility

Answer 24

Overall a more diverse community is more resistant to increased interspecific competition

ex. Ceader creek experiment: niche complementarity leaves less available nutrients for invaders

Question 25

Marine Defaunation: Animal Loss in the Global Ocean" abstract are:

Answer 25

Lower Extinction Rates in Marine Systems – The extinction rates of marine species are currently lower than those in terrestrial environment - may be a large extinction pulse about to hapen Differences in Mobility and Population Structure – Many marine species have higher mobility and different population structures compared to terrestrial animals. This affects how they respond to human pressures, such as overfishing, and influences conservation strategies. - Marine protected areas like corridors and proper management of these areas is key Marine Conservation Requires Different Approaches – Effective ocean conservation needs well-enforced marine protected areas, better fisheries management, and strategies that consider the unique characteristics of marine ecosystems, as traditional terrestrial conservation methods may not be directly applicable. - This is going to be an issue over next 150 years

Question 26

Defaunation in Anthropocene

Answer 26

- widespread loss of animal populations due to human activities, leading to both species extinctions and significant declines in local population abundance. The authors highlight that while much attention has been given to habitat destruction and climate change, defaunation— the direct loss of animal life— is an underappreciated driver of ecological change. They emphasize that vertebrate populations have declined by an average of 25%, while invertebrates have suffered even greater losses, with some groups showing a 45% decline in abundance. These losses disrupt ecosystems, reducing their stability and impacting human well-being. The paper argues that understanding defaunation is crucial for predicting and mitigating biodiversity loss, as it is a major factor in the planet’s ongoing sixth mass extinction.

Question 27

What percent of species were lost since last mass exstinction

Answer 27

50%

Question 28

Transgressive overyielding

Answer 28

One species niche will only occupy part of an area If you maximize diff in plants they can each occupy their own niche and occupy 100% of the biomass available

Question 29

Selection effect and homogenous habitat

Answer 29

selection effect (SE) dominates over niche complementarity (NC) in a homogeneous habitat. This means that in simpler environments, ecosystem function is more dependent on a few dominant species rather than biodiversity-driven processes.

Question 30

Niche complementarity in heterogenous

Answer 30

Niche complementarity (NC) has a much higher value, supporting the idea that species interactions enhance ecosystem functioning in heterogeneous environments.

Question 31

Take away from alge experimentharr:

Answer 31

Greater species richness improves nutrient cycling (NO₃⁻ uptake) and biomass, especially in heterogeneous habitats. Niche complementarity plays a stronger role in structurally complex environments, while selection effects dominate in simpler habitats. This experiment supports the idea that biodiversity enhances ecosystem services like water quality, particularly when environmental complexity allows for species to use different resources efficiently.