Community Ecology Test 1

Front 1

What are the essential rates?

Back 1

growth, birth, and death rates

Front 2

List the common ways to sample a population.

Back 2

Quadrat survey
Random walk
Line transect
Point survey
Mark and recapture
Traps and passive collecting

Front 3

When are quadrat survey's used?

Back 3

Spatial subsampling, most often used with plants or fixed things such as corals, nests, burrows etc.

Front 4

What is a nested design?

Back 4

When a smaller quadrat is placed within a larger quadrat.

Front 5

What are the most common sized quadrats and when are they used?

Back 5

0.1 ha used for quick
and dirty forest census

5m quadrat used for rocky intertidal surveys, and seedlings.

1m quadrat used for intertidal and herbaceous plants including seagrass

Front 6

How do you know what sized quadrat to use?

Back 6

When the species diversity levels off

Front 7

What type of sampling is a "random walk/swim"?

Back 7

Spatial subsampling.

Predetermined distance and compass bearings (random).

Document target organisms encountered.

Front 8

What makes up a point survey?

Back 8

Spatial subsampling

Randomly selected points (or could be regularly spaced along line transect).

Document all target organisms within given radius (varies according to organism).

Front 9

What is the formula for population index?

Back 9

P= (100 NA)/L,
where:
P = population index,
L = length of transect in meters
A = size of flight area in hectares, and
N = butterfly numbers per 100 m of transect.

Front 10

How is a point-quarter survey used?

Back 10

Orientation of one axis can be chosen by random number (0-180o). Then distance to nearest individual is measured in each quarter.

Front 11

What is the "Mark and Recapture" method?

Back 11

Catch N number of a population at time 1.
Mark them (paint, clipped toes, tags)
Return at time 2 and resample same number from population and count the number (M) that are marked (i.e. recaptured)

Front 12

What is the formula for total population size?

Back 12

Total population P = na/r
where
P = total population
a = marked
n = total recaptured
r = marked recaptured

Front 13

What are the assumptions for the Mark and Recapture method?

Back 13

marking doesn't affect animals (behaviorally, physiologically, or ecologically);
marked animals are completely mixed in population;
probability of capturing a marked animal is the same as capturing an unmarked animal (closed population);
marked animals don't lose their marks;
marked mix naturally with unmarked.

Front 14

List passive types of collecting population samples.

Back 14

1. Pitfall traps for small reptiles and beetles
2. Cover boards
3. Light/black light trap
4. Plankton sampling
5. Soil fauna sampling using Berlese funnels

Front 15

List the more common types of experiments.

Back 15

Exclosures
Reciprocals
Additions
Growth responses

Front 16

How do you test exclosure experiments?

Back 16

Trying to measure the effect that one organism has on a system. Try getting rid of the organism.
Hunt them out and then keep them out using Exclosures.
Then monitor changes in other populations or habitat.

Front 17

How do you test reciprocal experiments?

Back 17

Observation: The same species of plant grows in two locations, but the ones at location A do better than at B.
Q: Is this pattern because the popn at A is better suited to conditions (evolutionary adaptation) or because location A is a better site?
Can test this by taking members of popn A and planting them at B, and taking some from B and planting at A. What happens?

Front 18

How do you sample at large scale?

Back 18

Data mining and using GIS (Geographic Information Systems )

Front 19

What is the sequence of study?

Back 19

1. Research the topic: what has already been done and what questions raised?
2. Formulate research question.
3. Decide if you are going to look for correlation or causation.
4. Statistics that you apply can then be hypothesis testing (ANOVA, MANOVA) or descriptive/hypothesis generating, e.g. Multivariate analysis and modeling.

Front 20

Why are descriptive statistics needed?

Back 20

They identify pattern in complex data that allow better hypothesis formulation.

Front 21

In multivariate analysis, what is ordination?

Back 21

Ordination: Treating samples as lying along continuous gradients. More realistic but a bit harder to understand at first.

-Performs similarity analyses and then maps the data points so that similar samples are clustered together, but segregated from those that are dissimilar.

Front 22

In multivariate analysis, what is classification?

Back 22

Classification: Dividing things into groups. Very intuitive as that is how our brain works, and can be useful to help us think about a problem, but artificial.

Front 23

What is a community by definition from Clements theory?

Back 23

It acts as a super organism

Front 24

What is a community based on Gleason's theory?

Back 24

It acts from individuals responses, not as a whole group.

Front 25

What are the types of ordination?

Back 25

Principal components analysis (PCA)
Detrended correspondence analysis (DCA)
Canonical correspondence analysis (CCA)
Non-metric multidimensional scaling (NMDS)

Front 26

How are the various pools of Nitrogen cycled on the earth?

Back 26

Pools of Nitrogen:
- atmosphere is 70% N, but not available for uptake
- N in sediments and rocks , but not available
- inorganic N in ocean is another large pool
- organic pools in plants and soils actively cycled

Front 27

Describe the types of biological fluxes of nitrogen

Back 27

Fluxes: N moves between biosphere and atmosphere
- biological: fixation, denitrification, nitrification

Front 28

Describe the types of abiotic fluxes of nitrogen.

Back 28

- abiotic: industrial fixation, lightning fixation,
fossil fuel and biomass burning, deposition

Front 29

What organisms fix nitrogen?

Back 29

-Heterotrophic bacteria that get organic C from environment and where N is limiting (e.g., decaying logs)
-Rates low due to low C supply and lack of O2 protection (0.1-0.5 g-N m-2 y-1)
-Also, cyanobacteria (free-living photo-autotrophs); symbiotic lichens (cyanobacteria with fungi offering physical protection)
***NO PLANT FIXES NITROGEN we talk about N-fixing plants, but this is always a symbiont associated with the plant, not the plant itself.

Front 30

Why aren't plants labeled as N fixers?

Back 30

Because microbial symbiont resides in root nodules, the plants don't do it themselves.

Front 31

What is primary succession?

Back 31

Succession refers to more or less predictable and orderly changes in the composition or structure of an ecological community. Succession may be initiated either by formation of new, unoccupied habitat (e.g., a lava flow or a severe landslide) or by some form of disturbance (e.g. fire, severe windthrow, logging) of an existing community. Succession that begins in areas where no soil is initially present is called primary succession, whereas succession that begins in areas where soil is already present is called secondary succession.

Front 32

Is nitrogen an open or closed cycle?

Back 32

N cycles as a closed system….much more cycles internally than flows in. Oceans are the major player.

Front 33

Who fixes nitrogen more, nature or people?

Back 33

PEOPLE! OH NO!

Front 34

What happens if you "open" a closed system?

Back 34

‘Opening’ a closed system means that the nutrient is now lost from the system..often washing out in streamwater or being volatalized as smoke Particularly true of N in fire-prone systems).

Front 35

What are "Redfield ratios?"

Back 35

C:N:P
106 C : 16 N : 1 P

Front 36

What nutrient is typically the limiting nutrient in most terrestrial systems?

Back 36

Phosphorus!

Most lakes are p-limited too

Front 37

What happens if phosphorus increases in a water system?

Back 37

Redfield ratios with alter and we will see algal blooms.
As the system degrades further it may become a bacterially-dominated rather than algal community…At that point you have a dead zone.

Front 38

What is the ratio of carbon in soil, vegetation, and atmosphere?

Back 38

Soils hold ~3 times as much carbon as vegetation or about twice as much as in the atmosphere.

Front 39

What is soil made of?

Back 39

Mineral matter (e.g. silica, aluminum, iron)
Organic material (decomposing squirrels etc)
Air
Water
Biota

Front 40

What 5 factors does soil formation depend on?

Back 40

1) Topography
2) Parent material
3) Climate
4) Biotic processes
5) Time

Front 41

What 4 components are released in soil from weathering?

Back 41

1) Minerals in solution (cations and anions), the basis of plant nutrition.
2) Oxides of iron and alumina (sesquioxides Al2O3, Fe2O3).
3) Various forms of silica (silicon-oxide compounds).
4) Stable wastes as very fine silt (mostly fine quartz) and coarser quartz (sand).

Front 42

How do air spaces benefit soil composition?

Back 42

Air spaces in soil are essential for keeping roots well supplied with oxygen.

Front 43

How do air spaces benefit degrade soil composition?

Back 43

Air spaces can fill with water. If filled for too long the soil becomes anoxic or waterlogged

Front 44

How does soil pore size contribute to water distribution?

Back 44

Large pores drain quickly (gravitational water).
Smaller pores provide water to plants.

Front 45

Where do soils derive their mineral nutrients from?

Back 45

Decay of parent material
Groundwater
N-fixing.

Cations are charged particles that are held on the surface of clays.

Front 46

What is the cation exchange capacity (CEC?)

Back 46

The degree to which a soil can adsorb and exchange cations.

Front 47

In general does CEC decrease or increase with increasing soil acidity?

Back 47

Decrease!!

Front 48

How does CEC work?

Back 48

When the cations are present in equivalent amounts, the order of strength of adsorption is:
Al3+ > Ca2+ > Mg2+ > K+ = NH4+ > Na+

So under normal conditions K + is more readily displaced (ie goes into solution) than Al3+

Plants use this to free cations from clays for absorption by pumping H + ions out of their root hairs.

If the soil becomes flooded by H + ions then this distorts the exchange and even H + ions can then displace Al3+.

Front 49

What role does soil animals play?

Back 49

Decomposition (shredding residues)

Mixing soil (aeration)

Front 50

Does organic matter decay faster in boreal, temperate, or tropical forests fastest?

Back 50

Tropical!

Front 51

What 2 laws of thermodynamics govern ecosystems?

Back 51

1. Energy can neither be created nor destroyed, only transformed from one type to another.
-conservation of energy
2. In any transfer of energy, some energy is lost.
-entropy

Front 52

What are autotrophs?

Back 52

Autotrophs: convert CO2 to organic carbon, i.e. all green plants and algae.
Variants being photoautotrophs (photosynthetic) and chemoautotrophs (deep sea vents, some bacteria).

Front 53

What are heterotrophs?

Back 53

Heterotrophs: Obtain carbon in organic form (predators or detritivores), i.e. all animals, fungi

Front 54

What defines primary production and its producers?

Back 54

Primary production – capturing light energy and storing it in chemical bonds of carbon compounds
primary productivity – the rate of primary production
primary producers – photosynthetic autotrophs

Front 55

How do plants use the product of photosynthesis?

Back 55

1. new proteins, tissues, cells, structures – growth & reproduction
2. fuel for the above processes

Front 56

What is gross primary production?

Back 56

Gross primary production (GPP) – total amount of energy assimilated by photosynthesis

Front 57

What is net primary production?

Back 57

Net primary production (NPP) – energy actually stored as biomass

Front 58

How do you measure NPP?

Back 58

energy per unit area per year
kJ per m2 per yr, or W per m2

1 g C assimilated = 39 kJ energy
can use plant biomass or CO2 uptake as an estimate of energy

Ignoring roots – annual aboveground net productivity (AANP)


Can measure via standing biomass or by CO2 usage.


Measure amount of CO2 absorbed by leaves
extrapolate from a very small area

Use radioactive isotopes to measure total uptake of C

In aquatic systems, measure changes in O2 concentration

Front 59

What can limit primary production?

Back 59

Light, temperature, water/nutrients

Front 60

What is the energy transfer rate in a food chain?

Back 60

With each step in the food chain, 80-98% of energy is lost

Front 61

What is Ecological efficiency?

Back 61

proportion of the biomass of one trophic levels transformed into biomass at the next higher trophic level.

Ecological Efficiency = Exploitation efficiency x Assimilation efficiency x Net production efficiency

Front 62

What is Exploitation efficiency?

Back 62

proportion of production on one trophic level that is consumed by the next higher level

Front 63

What is Assimilation efficiency?

Back 63

proportion of ingested energy actually absorbed by the body
EX:
seeds – 80%
young vegetation – 60-70%
grazing/browsing – 30-40%
wood – 15%
animals – 60-90%

Front 64

What is Net production efficiency?

Back 64

Net production efficiency = (biomass production)/(assimilated energy)
the proportion of energy not used for maintenance and not lost as heat

Front 65

What is Gross production efficiency?

Back 65

Gross production efficiency = (biomass production)/(ingested energy)

Front 66

Why is Assimilation efficiency of herbivores is only 30-70%?

Back 66

most plant tissue is not digested (cellulose, lignin, defensive compounds) by animals and ends up as detritus

Front 67

What are the 2 independent food chains?

Back 67

Herbivores and detritivores

Front 68

What is Ray Lindeman known for?

Back 68

Theorizing that 10% of energy flows from one trophic level to the next (Gross energetic efficiency). Untrue!

Front 69

What is Residence time?

Back 69

Residence time – average time that energy spends on one trophic level
= (energy stored in biomass)/(net productivity)

Front 70

What is the Biomass accumulation ratio?

Back 70

residence time based on biomass rather than energy
= (biomass)/(rate of biomass production)

Front 71

What is the energy passing rate for homeotherms? Poikliotherms?

Back 71

Homeotherms: 2-5%
Poikliotherms: 20-30%

Front 72

What are the 3 types of food webs?

Back 72

Connectance, energy, and redundancy.

Front 73

What is a Connectance food web?

Back 73

proportion of the potential links in the foodweb that are actually realized.

Front 74

What is an energy food web?

Back 74

web shows the relative flow of energy in the web

Front 75

What is a Redundancy food web?

Back 75

the number of links in the food web that perform the same ‘function’; complex foodwebs should have greater redundancy.

Front 76

What is the prey to predator ratio in a balanced ecosystem?

Back 76

Empirical studies show that the proportions of prey to predators is generally within the range of 2:1 to 4:1.

Front 77

What is omnivory in a food web?

Back 77

Omnivory is defined when a species is feeding on more than one trophic level.

Front 78

What are the 5 indirect interactions in a food web?

Back 78

1. Interference
2. Exploitation
3. Interspecific
4. Trophic cascade
5. Apparent competition

Front 79

What is the Optimal Foraging Theory (OFT)?

Back 79

-Predators will evolve to hunt in the manner most efficient to their physiology.
-Energetic argument: costs of hunting must be less than energy gain from feeding.
Costs are:
1. Hunting (from onset to capture)
2. Handling (from capture to digestion)

Front 80

What is Dominance?

Back 80

Dominance = basal area or aerial coverage, species A / area sampled

Front 81

What is Relative dominance?

Back 81

Relative dominance = basal area or coverage, species A / total basal area or coverage of all species.

Front 82

What is frequency?

Back 82

Frequency = intervals or points where species A occurs / total number of sample plots or points.

Front 83

What is relative frequency?

Back 83

Relative frequency = frequency value species A/ total frequency all species.

Front 84

What is the importance value?

Back 84

Importance value=
relative dominance + relative frequency + relative density*

Front 85

What is Simpson's dominance index?

Back 85

Measures the probability that two individuals randomly selected from a sample will belong to the same species


This index goes from 0 to the total number of species. An index of 1 is when all individuals belong to 1 species. When D ≈ 0 every individual belongs to a different species

D = SUM(Pi^2)
D = SUM ni(ni-1)/N(N-1)


Where D = Simpson’s dominance, between 1 and 0
ni = number of individuals in a given species (species i)
N = total number of individuals in the sample (community)
pi = proportion of individuals of a given species (species i)
S = number of species in the sample (community)

Front 86

What is alpha diversity?

Back 86

(within an ecosystem)
Species richness: number of species in a community
Species evenness: the relative abundance of individuals among species
Species dominance: measure of predominance of one or a few species in a community

Front 87

What is beta diversity?

Back 87

(between/among ecosystems)
Dimensionless number expressing the number of species gained going from one habitat to the next.

Front 88

What is gamma diversity?

Back 88

(within a region)
Dimensionless number expressing the diversity of habitats within a region, or a measure similar to b -diversity but across large geographic distances
Also defined as Geographic-scale species diversity

Front 89

What is the Shannon-Weiner Diversity Index?

Back 89

Similar to Simpson’s index except assumes an infinite number of individuals in the habitat.


H = Shannon-Weiner index
pi = proportion of individuals of a given species (species i)
S = number of species in the sample (community)
ni = number of individuals in a given species (species i)
N = total number of individuals in the sample (community)

Front 90

What is Evenness?

Back 90

Evenness is a measure of how similar the abundances of different species are.

Hmax = lnS ; E = H/Hmax

1>E>0