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Ecol 302 > ECOL Exam 2 > Flashcards

ECOL Exam 2 Flashcards

(90 cards)

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1
Q

Abundance- what it is and why we measure it

A

of individuals in a given location
Fundamental to ecology! It reflects fitness in different environments and helps with management and conservation

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2
Q

What do we need to know to measure abundance?

A

Measurement over time:
-Same life history stage
-Same time ineterval

Count
-Change in pop. size
-new individs = births, immigrants
-Missing individs- deaths, emigrants

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3
Q

Vital Rates

A

Rates of births, death, migration per Capita (per individual)

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4
Q

What are the 4 methods for getting a sample?

A

Plots
Transects
Traps
Complete Sampling

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5
Q

Plot Sample

A

Define a plot of any size and count all individuals in that area
- Most complete way to sample a small area
- Good for species that don’t move very fast
small portable plot frames = quadrats

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6
Q

Transect Plot

A

Straight Path through a habitat
-Best in difficult terrain/dense vegetation
-Best for very mobile species with a large transect

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7
Q

Trap Sample

A

Best for things that are hard to see or find
-This includes mark-recapture:
capture fraction of population
mark and release
recapture fraction
count # marked
calculate pop size

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8
Q

Complete (NOT a sample)

A

Count all individuals

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9
Q

λ =

A

1+ b-d
POP. Growth Rate

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10
Q

Geometric Model

A

Nt = λ^t * No

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11
Q

Birth Rate is

A

CONSTANT
but population increases at each time Step due to growing population size!

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12
Q

What do we multiply birth rate by?

A

Population Size (N)

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13
Q

Geometric Growth points plotted

A

set of POINTS = J shaped for geometric
exponential is j shaped line/CURVE
Both are straight on a logarithmic scale

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14
Q

λ= 1
λ>1
λ<1
λ=0

A

stable pop
increasing
decreasing
all dead

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15
Q

values of λ are called “growth rates” even when λ<1 and declining? True or False?

A

True

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16
Q

Why use a geometric Model?

A

It is discrete
-Pop size only predicted at specific, individual, time steps

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17
Q

When do you want to use discrete models?

A

-We observe populations at time intervals (observations are discrete)
-When a species has discrete time steps in its life (I.E. births at a certain time of year)

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18
Q

Exponential Growth Equation

A

dN/dT = rN

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19
Q

Logistic Growth Equation

A

dN/dT = rN (1-N/K)

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20
Q

K stands for what in the logistic growth equation

A

carrying capacity (level off line on graph)
BUT initial growth looks similar to exponential

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21
Q

Constant Vital Rates are what Models?

A

Geometric and Exponential

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22
Q

Density-Dependent Growth Rates are what math model?

A

Logistic

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23
Q

What math model is Stage/Age-dependent?

A

age structured model

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24
Q

Types 1, 2, 3 survivorship curves

A

type 1- most survive to old age (think letter D)
type 2- straight declining line- constant dying rate
type 3- most individuals die you (think L for loser) also think baby turtles

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25
What if we don't and cant find the age? what model then?
stage-structured MATRIX model
26
Sensitivity Analysis Steps
1) change a single transition rate 2) observe how λ or r changes (SENSITIVITY!)
27
Loggerhead Sensitivity Example
Increasing survival of older turtles had largest population growth effect
28
Why might populations not grow?
competition for food competition for space disease predators weather events/natural disasters These all increase as pop increases.Increase survival and repro increase all of these
29
In density Independence λ is . . .
NOT a function of density
30
In density Dependence λ is
changing as density changes
31
when λ=1 or r=0
population size does not change
32
Continuous Time Model
Nt = Noe^rt
33
Continuous Time Model if r=0 r>0 r<0
stable increasing decreasing
34
is r the same as λ
NO
35
Difference Between Logistic and Continuous
Logistic contains density effects
36
logistic with density effects
dN/dT = rN (K-N / K) take exponential growth and multiply by (K - N / K)
37
How does r defer from the model in comparison to how we would expect it to
R does not change in our model (it represents net growth per Capita which means growth rate - death rate) We would expect it to change in the real world
38
Can density dependent and independent be occuring at the same time?
lol yes
39
How to test for density dependence
Vary density and measure vital rates
40
How do density independent still manage to regulate population?
variability in vital rates
41
Are R selection dependent or independent?
independent
42
Are K selection dependent or independent?
Dependent
43
Deterministic Extinction
PREDICTED decline due to current vital rates *low fitness in current env't
44
Even if Extinction is NOT predicted how can populations go extinct?
Stochastic Vital Rates (unpredictable/random)
45
Populations with the same vital rates can have one grow and one go extinct due to
stochasticity
46
Can we average vital rates?
This does not take into account variability differences across INDIVIDUALS (especially considering life stages)
47
4 Truths of Stochastic Variation
1) Variation ALWAYS leads to a decreased growth rate than expected from average 2) Extinction can occur even if populations grow 3) different populations with same vital rates can still have very different outcomes 4) small pops more at risk
48
Population Variability Analysis
summarizes many simulations Gives us the probability of extinction within a given time from a set of stimulations
49
Steps to create a stochastic Model
-start with any population model -vary the vital rates at each time step -repeat for many simulations to see range of outcomes
50
2 types of stochasticity that impacts small populations
1) environmental (vital rates vary with environment) 2) demographic stochasticity - vital rates vary between individuals
51
Metapopulations
network of populations that can individually go extinct but be recognized via dispersal (need to have suitable uninhabitated patches nearby to colonize)
52
What does the persistence of metapopulations rely on?
empty patches being available
53
Levin's Model
CP(1-P)-ep c= colonization rate e= extinction rate p= proportion of occupied patches (1-p)= empty patches available
54
Vital Rates: population level/ birth and death model
Metapopulation Model
55
First Fisheries overfished and led to fishery "collapse" this means what
means NO CATCH (no more fish to catch )
56
MSY (maximum sustainable yield)
Find the conditions under which we can maximize harvest without driving the population down
57
idea behind MSY in regards to fishing
*MSY at the population size which the most fish are produced *take these and pop will stay about the same *and MAX harvest without decline
58
MSY target was what?
1/2 K
59
Problems with MSY
*what is the model problem? -measuring pop size and catch -bycatch (catching the wrong thing) -economics (supply and demand) -getting people to comply ALSO environment changes (vital rates!) and evolution
60
response to MSY 1: Optimum Sustainable Yield
MSY but with social, economic, and political factors taken into account
61
response to MSY 2: sustainable fisheries
forget MSY or optimum- just avoid collapse. MSY is a limit but not the goal (more complex model)
62
Invasive Species
species introduced (by humans usually) beyond its own dispersal abilities
63
ecological definition of invasive species
an introduced species that increases to high abundance
64
Popular Definition of Invasive Species
unwanted or causing harm (economic, health, conservation, etc)
65
Intentional Intros
Biocontrol agrculture recreation (fish stocking) whim! Example= starlings (Shakespeare bird intros)
66
An introduced species that increases to high abundancee must do what 2 things
establish a population and be highly successful
67
what percent of intros are actually successful
30%
68
Challenges with climatic niche model
incomplete or incorrect occurrence locations defining suitable conditions
69
what is the realized niche
Records of suitable conditions and occurrence locations
70
To avoid deterministic Extinction with introductions then the species must do what
intro must be within the niche
71
why might the climatic niche prediction work between home range and invasion?
Changes to biotic interactions in the home range that are not present in the invasion
72
Allee Effects
small populations introductions -Difficulty finding mates, social groups Allee is POSITIVE density dependent! Vital Rates increase with density
73
Positive Den Dep at Negative DD at
low density high density
74
Why do some invasive species become highly abundant?
Novel Niche Novel Weapons Enemy Release
75
Novel Niche Hypothesis
invasive species have access to a resource that others do not (lampreys blood sucking no competition)
76
Novel Weapon Hypothesis
Invasive Species can fight off competitors or enemies in a way others cannot -superior defense -superior competitior -changes ecosystem to harm other species (bufflegrass)
77
Enemy Release Hypothesis
Invasive Species left behind enemies that reduced their populations and they do not have new effective enemies *don't have to invest as much in defense (trade offs in life history!!) This is why biocontrol is important
78
3 things required for enemy release
enemies control invader in homeland enemies not in into no new enemies to control in invaded area
79
Distributions tell us how . . .
species are interacting with their environment at different scales (abund= how many and district= location)
80
What Limit distribution?
Proximate Reasons and Ultimate Reasons
81
Proximate Reason for lack of distribution
immediate, ecological interactions **Fitness or dispersal limitation
82
Ultimate reason for lack of distr. (4 REASONS!)
underlying causes, evolutionary Mutation- no adaptive variation Gene Flow- from core env't Genetic Drift- small edge pops Extinction
83
Is there a lack of adaptation beyond the range edge
Yes
84
what creates a broad range?
dispersal to available habitat high fitness in a range of environments: Adap plasticity and local adaptation
84
Hutchinsonian Niche
suitable range of environments (not locations) requires 1) fundamental niche 2) realized niche within the fund.
84
Adaptive Cline
local adaptation along an environmental gradient
84
Narrow Range Caused by
Low Dispersal (large distance between habitats) Low fitness outside current env't (specialization)
85
hutch fund niche
env't that a species can survive and repro in if free from effects of other species
86
realized niche hutchinson
fund niche modified by interaction with other species
87
steps for a climatic niche model

Ecol 302 (2 decks)

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