BIOL 370 Part II Flashcards
(410 cards)
1
Q
percent of population persisting vs time
A
-populations less than 100 have low probability of persisting >50 years
2
Q
negative density dependence
A
- population growth is negatively effected by its density
- examples: crowding, predators and competition
3
Q
sources of variation in population growth
A
- environmental stochasticity
- demographic stochasticity
4
Q
stochasticity
A
- model in which parameters vary unpredictably with time
- random, chance events in nature
5
Q
environmental stochasticity
A
- unpredictable environmental changes
- NOT: predictable ∆ like seasons; env’t trends
6
Q
geometric mean
A
(π λ_i) ^ 1/n
7
Q
incorporating stochasticity into population growth model implication
A
- makes pop growth slower than expected form constant growth
- variance in N_t increases w/ time
- variance in N_t proportional to both mean, variance of r
8
Q
Extinction from environmental stochasticity likely if
A
var(r) >2r
var(r) is greater than 2r
9
Q
what does a per capita birth rate of 0.2 mean
A
- for every z individuals we expect 0.2z new offspring in a year
- eg. 20 in a pop of 100
10
Q
P_birth
A
= b/(b+d)
11
Q
populations with high b and d
A
much higher demographic stochasticity than ones w/ low rates, even for same r
12
Q
what changes in demographic stochasticity
A
only b and d, r stays same
13
Q
P_death
A
= d/ (b+d)
14
Q
P_extinction
A
= (d/b)^No
15
Q
density dependence
A
birth and death rates are affected by density
16
Q
the simplest model of density dependence
A
logistic growth
17
Q
logistic growth assumptions
A
- linear density dependence in vital rates (b, d)
- decline in per-capita growth as density increases (negative dd)
18
Q
exponential growth
A
dn/dt = rN_t
19
Q
intrinsic rate of population increase r
A
r = per capita births b’ - per capita deaths d’
20
Q
exponential growth with intrinsic pop growth
A
dN/dt = (b’-d’)N_t
21
Q
exponential vs logistic growth, N vs t
A
exp: exponentially increasing
log: S-shape, increase to asymptote
22
Q
exponential vs. logistic, dN/Ndt vs N
A
exp: linear (flat)
log: linear decreasing
23
Q
logistic growth
A
dN/dt = rN_t (1 - (N_t / K)
24
Q
theta logistic population growth
A
dN/dt = rN(1-(N/K) ^ θ)
25
θ = 1
- linear effects of density on pop growth rate
| - logistic growth
26
θ > 1
- convex relationship
| - density dependence stronger at high density
27
deterministic factors
- intrinsic (eg. density dependence)
| - extrinsic (eg. seasonal ∆ in envt, long-term trends, species interaction)
28
sample variance
- sampling error
| - adds undesired variability in pop. growth beyond true variation
29
recovery plans and population size
less than 50% of record plans include estimate of current pop size, N
30
why estimating population size is challenging
- expensive
- time consuming
- biological challenges
31
biological challenges to estimating pop size
- detectability
- mobility
- wide ranges
- non-uniform distribution
32
managing fisheries is like
managing a forest of invisible trees that move around
33
θ less than 1
- concave relationship
| - density dependence stronger at low density
34
all animals are counted
census
| -perfect detectability
35
number of individuals
abundance
36
abundance estimate
actual estimate, often accounting for detectability
37
index
some measure assumed to be proportional to abundance or density (relative abundance)
38
random sampling
- unbiased
- representative
- can be inaccessible
39
abundance per unit area
density
40
common wildlife abundance indices
- track count
- scat
- vocalizations
- # captured/observed per day
41
difficulties with abundance indices
- only reliable if standardized and w/o confounding variables
- index changes: temporal, spatial, technological, observer
42
abundance indices temporal changes
-diurnal vs nocturnal
-seasonal
temporal ∆ doesn't necessarily mean a pop. ∆
43
abundance indices spatial changes
- schooling
- depth
- range contraction
44
estimating abundance w/ detectability
```
^N= c/ ^p
c = observed count
^p = estimated detectability
```
45
common abundance estimation techniques
- distance sampling
- double sampling
- multiple observers
- mark-recapture
46
Lincoln-Peterson
```
mark-recapture methods
N = ms/r
m = number marked
r = # w/ markings on 2nd sampling
s = total # captured on 2nd sampling
```
47
marking individuals
radio telemetry, PIT tag, banding, elastomer, photography, genotyping
48
capturing individuals
physical or non-invasive (genetic hair/scat, photography)
49
Lincoln-Peterson assumptions
- closed population
- all individuals have equal opportunity of being caught
- no effect of marking on recapture or survival
- complete mixing of marked/unmarked
- marks not lost
50
sources of variation in population abundance estimates
- deterministic factors
- process error
- observation/ measurement error
51
process error
stochasticity
52
sensitivity
how much lambda changes/ change in given vital rate; absolute change
53
problem w/ sensitivity
survival and fecundity are on different scales
54
elasticity
proportional λ∆ in a given vital rate
| -how a small, proportional change in rate will affect overall pop growth
55
sensitivity and elasticity, importance of survival
- survival more important than fecundity
| - survival relatively more important in longer-lived organisms
56
adult survival in long-lived organisms
- highest elasticity
| - lowest variability
57
relative strength of forces driving African cheetah population
inside protected areas:
- lower cub survival due to lion, hyena
- higher adult survival less human conflict
- adult survival key for pop. growth
58
a large increase in a vital rate (eg. 10%) with low elasticity
can outweigh a small change in a vital rate w/ high elasticity
59
viability
probability of extinction
60
PVA
population viability analysis
61
population viability analysis
quantitative assessment of probability a pop. will become extinct or quasi-extinct w/i specified time frame
62
Types of PVA
- count-based
- demographic
- metapopulatin
- spatially-explicit (powerful, but dada hungry)
- individual-based (computationally intensive)
63
count-based PVA
- unstructured population
| - uses time-series of abundance or density
64
demographic PVA
- structure population
| - uses matrix-models, sensitivity analysis, etc.
65
quasi-extinction
or pseudo-extinction
- easier to estimate than extinction probability
- chance that pop. will hit some critical minimum threshold
- can be used to reflect management options
66
example of quasi-extinction use
-species are listed on SARA if pop. drops below threshold of 50 individuals
67
PVA goals
- Assess extinction risk (probabilities of single pop., relative risk of multiple pops.)
- guide management (ID key life stages as management target)
68
PVA tools
population models
69
simplicity vs realism trade-off
simplicity: low data demand, few assumptions, broadly applicable, unrealistic, limited biological insight
realism: high data, many assump., narrowly applicable, realistic, biologically detailed
70
what can we learn from Number of individuals (N_t) vs time (t), simple unstructured PVA
- range of values pop. is likely to take
| - estimated probability of extinction (or pseudo-extinction)
71
usefulness of PVAs dependent on
- data quality
| - assumption that future pop. dynamics will be similar to present
72
Demographic PVA
- incorporates age/stage structure and age/stage specific vital rates
- may also include: sex-specific rate, variance/covariance in vital rate, dd, inbreeding depression, allee effects, env't/demo stochasticity, animal behaviour
73
Key PVA points
- remain aware of data quantity, quality
- always show CIs around variability estimate
- view viability metrics as relative not absolute
- shorter predictions more realistic
- keep simple, but be aware of what is left out
- consider multiple models
- consider PVAs as work in progress
74
PVA simple model example
breeding pairs owls vs year
-count individuals over time
-estimate trend
project forward
75
PVA demographic structure example
- add life stages: fledgling, juvenile, sub-adult, adult
- add competition from other species, barred owl
- spatial structure: potentially suitable owl habitat
76
Sumatran orangutan demographic PVA
-add year-to-year stochasticity, rare catastrophic events
77
what can be learned from orangutan PVA
- complexity can always be added (dd, competition, allee, spatial complexity)
- if there are data it can be modelled
78
questions to ask about habitat fragmentation
- how many protected areas
- what configuration
- how big should each be
- what shape should each be
79
landscape ecology
-study of how spatial patterning of landscapes affects behaviour, populations, diversity of organisms, as well as the functioning of ecosystems
80
IBT equilibrium theory
equilibrium where colonization = extinction
81
which type of islands will have greatest equilibrium number of species under IBT
large, near source population
82
why IBT is important for designing protected areas
-extinction rate increases for small fragments isolated from source pop.
83
faunal relaxation
reduction in diversity following a reduction in habitat area or creation of habitat island within formerly continuous habitat
84
faunal relaxation in national parks
extinctions after park establishment vs area of park
- larger parks = less extinctions
- most parks are not large enough to support MVP
85
SLOSS
- single large or several small
| - depends on overlap
86
nested diversity
-collection of species found in a given small area overlaps extensively w/ other areas and large areas contain these species plus more
87
edge effects
- more light, wind
| - could result in dessication
88
habitat lost to edge effect, shape and size
- too small and all of core habitat is lost
| - shapes that maximize SA:V minimize core habitat, i.e. long slender rectangle
89
metapopulation
- set of spatially isolated pop.'s of same species that interact on some level
- small subpops w/i fragments
- prone to local extinction
- connected by dispersal
90
metapopulation regional persistence
extinctions must be balanced by colonizations
91
Theoretical spatial ecology
- homogenous space
| - focus on population dynamics
92
metapopulation spatial ecology
- habitat is suitable on a patch basis
| - consider only patch sub populations
93
landscape spatial ecology
- landscapes is a complex mosaic varying in suitability, area, isolation, shape
- less emphasis on modelling pop dynamics
94
example of meta population with regional persistence
- Glanville fritillary, butterfly
- small populations of specialists
- high local extinction and colonization
95
habitat suitability
- not all patches are equal
| - source-sink metapopulations
96
source-sink metapopulations
maintained only by dispersal from elsewhere
97
turnover of patch occupancy
- some habitat patches newly colonized, some extinctions, emmigration, immigration
- fraction colonized changing
98
key metapopulation concepts
- unoccupied, suitable habitat can be very important
- reduced dispersal success can result in extinction
- critical threshold for habitat destruction
- patch arrangement and connectivity just as important as absolute #
- local events depend on regional context
99
critical threshold for habitat destruction
-metapop can become extinct long before all habitat patches are destroyed
100
aiding patch colonization
dispersal corridors
| eg. wildlife overpass
101
corridor experiment results
corridor increased SR in native species but not exotics
102
potential problems with corridors
- straight edge effect (long thin rectangle)
| - increased exposure, predation
103
SLOSS Hawaii, Galapagos
- rank islands from smallest-largest and largest-smallest
- plot cumulative species vs. cumulative area
- find more species for less area in both s-l lines
- lots of small patches probably better
104
conservation genetics can
- ID unique evolutionary lineages
- monitor dispersal, movements
- estimate pop. size
- trace genetic changes through t
105
evolutionary change in population is a function of
amount of genetic diversity available
106
genetic issues in conservational biology
- deleterious effects of inbreeding
- loss of genetic div. and ability to evolve
- fragmentation, reduction in gene flow
- genetic drift overriding natural selection
- accumulation of deleterious mutations
- adaptation to captivity
- resolving taxonomic uncertainties
- defining management issues
- outbreeding depression
107
problems with genetic adaptation to captavity
adverse effects on reintroduction success
108
primary level of biodiversity
diversity measured at the level of genes, or quantitative genetic traits
109
reduced genetic diversity causes
lower ability to withstand extremes
110
genetic variation depends on
- the species/population
- genome/ chrmosome region
- part of the gene
- whether sequence/ nucleotide codes for anything
111
Theodosius Dobzhansky
Nothing in biology makes sense except in the light of evolution
112
adaptive radiation
- morphological and genetic diversity from founder species (ancestor)
- diversification of a group of organisms into forms filling different ecological niches
113
types of genetic markers
- allozymes
- microsatellite DNA
- single nucleotide polymorphisms
- direct DNA sequencing
114
allonymes
- protein variants
- grind up organism, liberate DNA, gel electrophoresis, compare protein differences
- indirect way of looking at DNA changes w/o examining DNA
115
microsatellite DNA
- genetic variants in a section of b.p.'s
- short repeated sequences = microsatellite
- examine size of microsatellite w/ PCR
116
single nucleotide polymorphisms
- SNPs
- single bp change
- many thousands per individual
- used for individual-tailored medical treatments
117
DNA sequencing improvements
- large scale high throughput
- lower cost/b.p.
- lower cost/genome
- single molecule sequencing
- portable sequencer
118
cost of getting genome sequenced
ca. $1000 US
119
Hardy-Weinberg assumptions
- diploid organism
- sexual reproduction
- nonoverlapping generations
- identical allele frequencies in both sexes
- random mating
- large pop
- no migration, mutation, selection
120
frequency of heterozygotes
2pq
121
frequency of homozygotes
q^2
or
p^2
122
frequency of heterozygotes maximum when
p = q = 1/2
123
forces that effect allele frequencies
- migration
- mutation
- drift
- selection
124
raw material of diversity and evolution
mutations
125
vast majority of mutations
deleterious
126
germ cell vs somatic cell
- gametes arise from germ cells
| - somatic cells are all other cells besides reproductive
127
polymorphism rate
- much lower in nature than we expect
| - mutations are rare
128
fate of a mutation
- die out or persist, quickly or slowly
- depends on factors that enhance or downgrade mutation effect (drift, mutation, selection, etc)
- depends on effect on fitness, genome neighbours
129
natural selection requirements
- must be phenotypic variation in pop.
- variation must result in fitness differences
- variation must be heritable
130
types of selection
purifying selection
| positive selection - directional, balancing
131
purifying selection
removes deleterious mutations
132
random genetic drift
- chance/ random event allele frequency fluctuation
- drift direction unpredictable (especially in small pop.)
- reduces variation w/i pop.
- causes populations to diverge from one another
133
how does random genetic drift reduce population variability
- causes lost off alleles
- increase homozygosity
- decreases heterozygosity
134
random genetic drift example
x # marbles in a jar
- some fraction passed on at random
- unique combinations for each sample repitition
- smaller sample = higher chance of misrepresenting true pop.
135
favours beneficial mutations
positive selection
136
fixation of a beneficial mutation
directional selection
137
genetic bottlenecks
- relatively large pop is reduced to very small # by catastrophic event
- non-natural selection related
- bottleneck survivors likely have low level of genetic diversity and usually carry non-representative collection of source pop. alleles
138
founder effect
small # individuals form a pop. with low diversity
- may be positive, negative, or all new
- rare alleles present more often due to bottleneck effect
139
inbreeding coefficient
probability that alleles in an individual are identical by descent, homozygosity
140
number of eggs that fail to hatch vs inbreeding coefficient
increasing exponentially as inbreeding increases
141
inbredding coefficient vs generations for N=i
- for i = low population increase exponentially until completely inbred
- for i = 500 linear increase
142
balancing selection
maintains polymorphisms
143
MVP
- minimum viable population
| - smallest population that will not exacerbate inbreeding effects
144
% homozygosity vs # generations of inbreeding
smaller pop. increases to complete homozygosity exponentially
145
F = 1/4
brother-sister matings
146
Effective population size
N_e
- N_census > N_e
- not everyone in pop. contributes to reproduction
- fluctuation of N_e influences genetic drift
- difficult to measure
147
N_e : N_c
- generally 0.1 - 0.2
| - i.e. for every 5-10 indiv. only 1 breeding individual
148
fixation index
- a measure of the difference in the allele
| - increased in small populations
149
F statistics
-useful to summarize reduction in heterozygosity at different scales and due to different processes
150
F = 1/16
means children of first cousins
151
reduction in heterozygosity due to
- bottlenecks
- founder effects
- population structure
- inbreeding
152
barrier to migrations
- subdivide populations
| - decrease heterozygosity
153
isolated population
- can see reduced gene flow
| - in real life we can not
154
without barriers to migration we expect to see
HW ratios of homozygosity : heterozygosity
155
Sewall Wright's F statistic
- reduction in heterozygosity at one level of of pop. hierarchy relative to another level
- popular, useful measure of pop. differentiation
156
F_ST levels
```
0-0.05 = little structure
0.05 - 0.15 = moderate
0.15 - 0.25 = high
>0.25 = very high
1 = full homozygosity, no breeding
```
157
no gene flow =
genetic divergence among subpopulations
158
F_ST =
1/(4Nm + 1)
N_e*m = number of migrants
N = drift
m = migration
159
Equilibrium fixation index F^ vs number of migrants per generation (Nm)
- negative exponential
- high F = very great divergence
- low F = little divergence
160
migration
- reduces pop. structure
| - can balance drift
161
Ne*m =~
(1 - F_ST)/ 4F_ST
F_ST = (H_T - H_s) / H_T
H_s = average heterozygosity of sub pop.
H_T = average allele frequency
162
the 50/500 rule
- N_e should be at least 50 to avoid inbreeding depression (loss of fitness)
- N_e should be at least 500 to avoid eroding evolutionary potential (evolve and adapt to env't ∆)
163
revised 50/500 rule
- not good enough
- Ne >100 required to limit inbreeding depression to 10% over 5 generations
- Ne >1000 required to retain evolutionary potential
164
phylogeny
history of descent of a group of taxa from their common ancestors
-includes order of branching, absolute ages of divergence
165
cladogram
- only shows branching points, divergences
| - no distances implied by length of lines
166
reconstructing phylogeny
- ID, score taxa for phylogenetically informative characters
- model how evolution might have given rise to the states we see
- ID tree most compatible w/ data
167
homoplasy
character shared by a set of species but not present in their common ancestor
168
homology
existence of shared ancestry between a pair of structures, or genes, in different taxa
169
molecular clock
how fast DNA sequences change over time
170
why gene tree doesn't always = species tree
- horizontal gene transfer and hybridization
- incomplete lineage sorting
- different rates of evolution
171
red panda most closely related to
other weasels, raccoons, skunks
172
Levin model
-assume a large set of identical habitat patches with 'global' dispersal
-df/dt = C - E
df/dt = are of change in fraction of occupied suitable patches
-c = colonization rate
-e = extinction rate
173
E (extinction rate) =
p_e * f
| p_e = probability a pop. in an occupied patch becomes locally extinct
174
patch occupancy
- determined by a balance between colonization and extinction (independent events)
- colonization rate increases until few patches left to colonize
- extinction rate increases as colonization increases
- equilibrium where the two cross
175
how does additional habitat destruction affect population viability, Levin's model
- lowers colonization curve = equilibrium shift left
| - if colonization is lowered too much, p_e>c, f = 0, entire meta population extinct
176
key implications of Levin's Model
- empty habitat patches are not dispensable (new colonizations)
- there are critical thresholds (habitat destruction, dispersal barriers) below which entire metaphor. doomed to extinction
177
same total habitat but smaller patches, Levin's model
colonization curve = same
| extinction line = steeper
178
same patch size, fewer patches, Levin's model
colonization curve decreased
| extinction line same
179
key concepts from meta population theory
- unoccupied suitable habitat important
- reduced dispersal success can cause extinction
- critical thresholds for habitat destruction
- arrangement and connectivity of patches can be just as important as absolute habitat
- local effects depend on regional context
180
demographic matrix model
- structured population
- start with life cycle diagram
- convert to demographic matrix model
181
demographic matrix model M =
```
b1 b2 b3 ...
p2,1 0 0....
0 p3,2 0....
births across top
survival on diagonal
px, y = prob of surviving from age y to x
y = column
x= row
by = # offspring produced by individual of age y that survive to enter next age class
```
182
number of births =
% of females that give birth x % of births that are female
183
practice of making conservation decisions based on evidence accumulated from similar studies
Evidence-based conservation
184
fewer patches, smaller patches, Levin's model
colonization curve decreased, extinction line increases, complete extinction
185
meta-analysis
quantitative s summary of the size of the treatment effect
186
levels of science
- government
- academic
- environmental/ NGOs
187
the top threats to at-risk species
- habitat loss/ degradation
- intrinsic factors
- harvesting
- pollution
- invasives
188
manipulative experiments can help determine
most significant threat and most effective management
189
experiments must be
- random
- replicated
- control for confounding variables
190
sea turtles
7 species, all endangered or threatened
- long-lived
- nest on beach
- disturbance to nest sites and bycatch
191
loggerhead turtle sensitivity analyses
- lambda much more sensitive to survivorship of stages 2-4
- traditional conservation focuses on wrong age class
- critical importance of increasing juvenile survivorship not obvious w/o modeling
192
TEDs
- turtle excluder device
| - lets turtle escape fishing net
193
Spring/Summer Chinook Salmon, biggest threat?
- dams most obvious
- others: CC, water use/pollution, fishing, hatchery issues
- brook trout?
194
ESU
evolutionary significant unit
| -demographically and genetically independent, significant pop. of the species
195
calculating birth in the demographic matrix model
b*p*µ
b = fecundity (number of eggs produced)
p = survival from age 0-1
µ = adult survival
196
SRSS chinook salmon and brook trout
- 12% higher survival when brook trout absent
- but correlation does not equal causation
- confounding variables in study (habitat quality, brook trout habitat may have different favourability)
197
Types of studies utilized to determine threats to SRSS chinooks
- demographic matrix model
- control impact studies
- regression approaches
- before-after-control-impact analyses
198
BACI
before after control impact analyses
- examines if impacted sites do worse after the impact relative to the control site
- combination of before/after and control/impact studies
199
conservation assessment most effective if
-hypotheses can be rigorously tested through well-designed manipulative experiments
200
When experiments are not feasible
- careful observations/ monitoring
| - modeling approaches (matrix, control-impact, BACI, regression)
201
adaptive management
- scientific approach to conservation
- projects are designed, managed, and monitored to maximize opportunities to learn from actions, test assumptions, and adapt future management in response to findings
202
reactive management
- managers deal w/ events as they arise or as new info becomes available
- do not systematically attempt to build learning into project design and implementation
203
Passive management
- course of action remains constant w/ no opportunity for new info to influence future actions
- usually no monitoring
204
are grey seals inhibiting recovery of Atlantic cod
- 20 years later cod have not recovered
- cull the seals and call it an experiment?
- can't control any of the other variables
- no evidence to support the hypothesis that killing seals will help
205
why so important to monitor?
spending conservation $ w/o rigorous evidence is ineffective and wasteful
206
when randomization is not possible
perform a quasi-experiment
207
confounding variable
variable besides hypothesized predictor, response variables that might lead to incorrect conclusions
208
hardest adaptive management decision
when to give up
209
protected areas
now typically intensively managed areas w/ some restrictions on human activities
210
IUCN categories of protected areas
strict nature reserves, wilderness areas, national parks, natural monuments, habitat/species management areas, protected landscapes, protected areas w/ sustainable use of natural resources
211
IUCN definition of protected area
clearly defined geographical space, recognized, dedicated and managed, through legal or other effective means, to achieve long-term conservation of nature w/ associated ecosystem services and cultural values
212
goal of protected lands
10%
| -surpassed goal
213
global growth of protected areas
-levelling off
around 70k areas
-around 18 million km^2
214
why are protected lands not increasing
- people weren't compensated for their lands
| - governments backing away from earlier commitments
215
why do protected areas typically require intensive management
- too small to maintain MVP
- overpopulation of some species
- invasive species
- enforcement against illegal logging and poaching
216
protected area costs
- monitoring
- science
- enforcement
- assessing quality
- removing non-native spp.
217
how to increase effectiveness of protected areas
- design them strategically
- enhance enforcement
- buy-in from local communities
- research and review goals
218
how to get support from locals
- compensate for their land/resources
- education
- involve them
219
conservation on privately owned lands
- 60% of at-risk species only on private lands
- purchase and protect lands (land trust)
- engage private land owners in voluntary contracts or legal agreements
220
paper park
protected areas existing on paper only, no enforcement
221
natural vegetation inside and outside of protected areas
significantly lower outside of protected area
222
GDP and change in forest volume
- no nation w/ per capita GDP > $4600 had shrinking volume of harvestable trees
- poor countries lowing forests, rich gaining (kuznets?)
223
habitat destruction often greatest
- in areas of highest biodiversity
- more to lose?
- more human dominated?
224
mountain logging
- on steep slopes = erosion, mudslides
| - drain into tributaries
225
Is habitat loss reversible from logging
- structure, function, recreational value - Yes
| - biodiversity- Maybe?
226
is habitat loss reversible from desertification
No
227
other impacts to forests
-road building = edge effects
228
FAO definition of forests
too broad
- overestimate global land area forested
- underestimate deforestation
229
FAO
Food and Agricultural Organizations of the United Nations
230
forest ecosystem services
- food
- timber
- fuel
- carbon storage
- nutrient cycling
- water/air purification
- social and cultural benefits
231
Introduced species
- non-native, non indigenous, alien, exotic
| - species that have been moved through human activities beyond their natural range
232
naturalized
- an introduced species that establishes
| - self-perpetuating
233
Invasive species
-introduced species that thrives, spreads, harms native species, ecosystems, and/or ecosystem services
234
The invasion process
uptake from native range --> transfer via vector --> release in new region --> establishment --> population increase and range expansion
235
Pathways of invasion
- intentional introductions
| - unintentional introductions
236
Intentional introductions
- European colonization
- Agriculture, horticulture, aquaculture
- Pet trade
- Biocontrol agents
237
Unintentional introductions
- stowaways: ship ballast, water, grain shipments, commercial freight, individual travellers
- escape from aquaculture facilities
- unregulated e-commerce
238
Southwest BC aliens
- eastern grey squirrel
- Japanese knotweed
- English Ivy
- House sparrow
- Scotch broom
- Himalayan blackberry
- European green crab
239
The tens rule
- 10% of imported species escape control/cultivation (eg. 100 out of 1000)
- 10% of these establish (eg. 10 out of 100)
- 10% of these become invasive (eg. 1 out of 10)
240
key points of tens rule
- not literal/exact
| - only a small proportion of introduced species actually become invasive
241
predictors of invasion success
- reproductive rate
- trophic level
- # times introduced
- habitat generalist
- diet generalist
242
most consistent predictor of success
propagule pressure
243
community invasibility
- susceptibility of a community to invasion
| - measured as presence, success, # invasives
244
what controls community invasibility
- disturbance
- diversity
- natural enemy release
- ecosystem health
245
community invasibility, disturbance
- frees resource and/or harms native species
| - habitat destruction, pollution create high levels of disturbance (reduced diversity, increased invasion)
246
community invasibility, diversity
-higher native diversity = lower risk of invasion
247
community invisibility, community health
- degraded ecosystem more prone to invasion
| - overexploitation removes competitors/ predators (low biotic resistance)
248
Biotic resistance hypothesis
- community w/ more species more resistant to invasion
| - more species = higher proportion of utilized available resources = less available for invaders
249
The Natural Enemy Release hypothesis
-degree of enemy release predicts invasiveness
250
ecological consequences of invasive species
- extinction
- dilution of native biodiversity (local, regional)
- biotic homogenization
- modify env't, alter ecosystem processes
251
direct mechanisms of invasive species consequences
- outcompete
- exclude
- predation
- disease
252
alines and extinctions
- >50% of documented animal extinctions
253
biotic homogenization
- the anthropogenic blender
| - establishment of exotics, loss of natives reduces regional differences
254
alteration of ecosystem processes and services by invasives, examples
- C4 grasses (eg. cheatgrass) increase fire frequency
| - nonnative N fixers change soil nutrients, facilitate other invasions
255
of invaders vs trophic level
producers - highest
consumers - lower
predators - lowest
-however predators can cause highest damage
256
economic consequences of invasive species
- reduce agricultural/ pasture productivity
- forest damage
- clog water intakes
- choke waterways
- health costs
257
what aliens cause forest damagae
insect pests
258
what alines clog water intakes
zebra mussesls
259
cost of aliens
- >100billion/yr in US
| - $840,000 million/yr
260
strategies for dealing w/ introduced species
Prevention: uptake and transfer stages
Eradication: release and establishment stages
Control: population increase and range expansion stages
261
prevention of invasives
- public education
- inspection (border control)
- regulation (empty ballast water)
262
eradication of invasives
- possible on islands and/or if species is easily removed, restricted in range, small pop., easily accessible habitat
- extremely difficult on mainland
263
invasive species controls
- biological
- restoration
- acceptance
264
what aliens have health costs
introduced diseases
265
Biological invasive control
- introduction of natural enemies (consumer, pathogen)
- difficult
- backfires
266
restoration control of invasives
-restore natives to minimize reinvasion
267
what aliens choke waterways
aquatic plants
268
lionfish
- from Indo-Pacific --> invading Caribbean, Atlantic
- largest magnitude marine invasion
- harming already stressed corals
- voracious, ambush predators
- well camoflouged
- 65% reduction in prey biomass over 2 yrs
- very low predator abundance
269
historical views of the ocean
- hostile, barrier
- mysterious, we don't occupy it
- bountiful, food source
270
current views of the ocean
- fun
- cute
- delicious
- endangered
271
Marine ecosystem services
- provisioning: seafood, timber, fiber, parhmaceuticals
- regulating: water quality, climate regulation
- cultural services: tourism, recreation, aesthetic, spiritual
- supporting services: nurseries
272
world fisheries value
- $240 billion
| - $10 billion in tuna alone
273
island nations
- 90% of ppl who derive livelihood from fishing live in developing nations
- 1 billion ppl in developing countries depend on fish for primary source of protein
274
types of fisheries
- recreational
- artisanal /subsistence
- industrial
275
artisanal fisheries
- communities w/ few resources
- nearshore, limited by fuel costs
- multi-species
276
artisanal fishery tools
- cast net
- seine net
- line
- spear
- trap: passive, non-selective
277
selectivity in fisheries
- more selective = better ecological impacts and management
| - more selective = lower by-catch
278
Industrial fisheries
- far ranging
- on-board processing
- onboard technology: GPS, fish-finder
279
Industrial gear
- purse seines: circle net, close like purse
- trawls: shrimp, groundfish
- longline: surface, pelagic, demersal; >2500 hooks, miles long
280
overfishing
fishing rate that exceeds maximum sustainable yield
281
MSY
- largest yield that can be taken over an indefinite period
- maintain high growth rates by reducing #s
- maintain stocks below carrying capacity
282
Effectiveness of MSY
- should be able to avoid overfishing if fish below MSY
| - ecosystems are complicated and we can't always predict what will happen
283
Problems w/ MSY
- hard to estimate: uncertain data
- stochasticity
- multispecies interactions difficult
284
tragedy of the commons
- everyone competing for common resource, only concerned about personal needs
- overuse and exploit
285
Who owns the ocean
historically everyone
- EEZs governed by nations ( 200 nautical miles offshore) -- 42% of the ocean
- high seas governed by UNCLOS
286
UNCLOS
UN Convention on the Law of the SEa
287
fishing subsidies
- US: $92 million/yr for boat construction, fishery development, tax exemption, fuel subsidy
- Globally: tens of billions /yr
288
Types of fisheries data
- catch data
| - Stock assessments
289
catches vs time
catch is all increasing - more fish?
| -no, just more effort, better technology
290
status of stocks vs time
1950s: 85% developing, 15% fully exploited
2000s: 40% collapsed, 30% over-exploited, 30% fully exploited
291
state of fisheries projection
global collapse of all taxa currently fished by 2048
292
human predation
- unsustainable super predators
| - prey on adults
293
catch data
- landings, CPUE catch per unit effort
- variable quality
- widely available
294
stock assessments
- model output: biomass, harvest rate
- high quality
- rare
- difficult to find
- no single database
295
why don't we see overfishing
- effort displacement, supermarket problem
| - shifting baselines
296
The supermarket problem
- overstocking
| - makes it look like sea is inexhaustable
297
effort displacement
when local populations become overexploited move to new ones, expand to underdeveloped regions
298
shifting baselines
our perception of what is normal changes across generations
299
mean fish size 1956 - 2007
1956 mean: 19.9kg
| 2007 mean: 2.3kg
300
why does overfishing happen
MSY often used as benchmark but difficult to estimate and regulate
301
how common is overfishing?
- difficult to know
| - 63% of assessed estimated to be overfished
302
coral holobiont
diverse community of organisms including endosymbiotic algae, protists, fungi, bacteria, Archaea, and viruses living w/i and on the coral
303
zooxanthellae genus
Symbiodinium
304
symbiosis benefit to coral
- productivity
- O2
- nutrient recycling
305
symbiosis benefits to zooxanthellae
- predator protection
- environmental regulation
- nutrients
- CO2
306
parrotfish
indirectly have positive impact on coral recruitment
307
2015-2016 weather
biggest El Niño on record + warm water anomaly
308
NOAA coral reef watch
- detect possible bleaching events based on SST
| - 7-day bleaching alert in Nov 2015
309
videophillia
the new human tendency to focus on sedentary activities involving electronic media
310
stochasticity
randomness, uncertainty, hard to predict the outcome, increases probability of extinction
311
demographic stochasticity
chance variation in ratio of sexes, reproductive success, etc.
312
to make conservation decisions must know
- # of individuals in population
- trend in pop. size
- estimated risk
313
less than 1/2 species on endangered species act have
known population size
| only 40% have trend in pop size
314
census especially difficult to obtain for
aquatic, subterranean, cryptic, highly mobile species
315
environmental stochasticity
fluctuations in env't conditions that affect reproduction/survival
316
relative abundance
of individuals sampled per unit effort
317
to estimate sample/pop of sessile/ sedentary species
quadrat sample
318
large sample size =
lower sampling error
319
random sample to
reduce/avoid bias
320
transects ideal for
vegetation, slow animals, gradients
321
Lincoln-Peterson method
```
capture, mark, release
m = # marked
allow time to remix
sample, s = #sampled
record # marked, r = recaptured
total pop N = ms/r
```
322
mark-recapture assumptions
- no effect of marking on individual
- no effect of marking on recapture
- mixing of marked/unmarked is complete
- captured indiv. represent whole pop.
- closed, stable pop.
- marks not lost/removed
323
mark-recapture assumption, no effect of marking on survival
- no more obvious to predator
- no increase chance of parasite/disease
- no increase to hunting
324
non-invasive sampling techniques
- photography (especially for dangerous or hard to sample species (tigers, whales)
- DNA (fecal, hair)
- aerial survey (open habitat)
- vocalization
- nests, burrows
- records, journals, fossils, pollen
325
discrete population change
N_t+1 = lambda * N_t
| -births, deaths occur in one big pulse per yr
326
population growth rate
λ = N_t+1 / N
λ > 1 growth
λ less than 1 = pop decline
327
Discrete model assumptions
1. density indepen. pop ∆ - shrinks/grows at constant rate
2. deterministic pop dynamics
3. homogeneous individuals
4. closed population
328
implications of density independent population ∆
- resources unlimited no matter how large
- no carrying capacity
- no trouble finding mates/resources for small pop. (allee)
329
implications of deterministic population dynamics
- no 'good' years and 'bad' years
- no stochasticity
- constant environment
330
implications of homogeneous individuals
- same reproductive success
| - same probability of survival, growth, behaviours
331
PVA
population viability analysis
| -combine current pop size, trend, estimated yr-yr variability, quantify prob of extinction w/i specified time frame
332
essential simple PVA info
- estimate of current pop size, N
- estimated pop trend, λ
- info about fluctuations in λ with time
333
MVP
min # of indiv. having a 95% prob. persisting over 50-100yrs
334
Threat analysis
- assess factors that cause pop decline
| - manipulative experiment, observational study, models
335
key elements to manipulative experiment
- confounding variables
- replication
- random
336
randomization important for
reducing bias
337
replication important for
discerning the signal from the noise
338
observational study
more realistic
- harder to discern cause and effect
- harder to control variables
339
sea turtles and conservation actions
- protect nesting sites, captive rearing, reduce mortality in open ocean
- increase prob. of juvenile survival to 1.0 -- find no change to pop decline
- increase large juvenile survival -- may reverse decline
- efforts should be focused on large juveniles, contrary to what was thought
340
sensitivity analysis
- systematically vary model inputs (survival, growth, fecundity)
- determine impact of each parameter to the system
- ID where conservation efforts most effective
341
dam impact
- survival of 1 yr old
| - survival/health of reproductively mature adults
342
determining conservation action of spring/summer chinook salmon
-demo matrix model: set survival of 1yr old, adult to 100%, pop still declines - dams not the biggest/only threat
343
landscape ecology
study of how spatial patterns of landscapes affects organisms and ecosystems (fragmentation, connectiveness, etc)
344
Equilibrium theory of island biogeography
- larger islands tend to harbour more species
- # species is a balance btw colonization and extinction
- low # species = large colonization potential, low extinction potential, pop tends to increase
345
faunal relaxation
reduction in diversity following reduction in habitat area
346
extinction debt
difference btw large # of species doomed to extinction from habitat loss/fragmentation, and the relatively smaller # that have already occurred
347
SLOSS, nested
single large
| -contains same species of the small patches, plus others
348
collection of spatially isolated subpopulations of the same species
metapopulation
349
rate of change of fraction of patches occupied
```
df/dt = C - E = colonization - extinction
E = p_e * f
C = C*f (1 - f)
p_e = prob. sub pop becomes locally extinct
f = fraction of patches occupied
```
350
land trust
non-profit organization dedicated to land protection
351
IUCN categories of protected land
1a. Strict nature reserve- human visitation/ activity strictly limited
1b. wilderness area - human habitation prohibited
II. National park - rec permitted, protect large-scale ecological processes
III. Natural Monuments- protect geological/living features
IV. Habitat/species management area- protect particular species/habitat
V. Protected landscape/seascape - preserve distinctive character produced by human/nature interaction
VI. Protected areas w/ sustainable use of natural resources
352
PADDD
protected area downgrading, downsizing, degazettement
353
Degazettement
loss of legal protection for entire national park or protected area
354
SLOSS, unnested
SS, patches contain unique species
355
Debt-for-nature swap
NGO pays some portion of nations debt and nation commits to conservation
356
management that utilizes learning by doing
monitor projects and allow for adaptations
357
if an action has a possibility of causing harm it should be avoided
precautionary principle
358
prioritizing species and ecosystem based on severity and likelihood of recovery
conservation triage
359
coral reef coverage
- cover less than 0.1% of Earth's surface
- 20% lost, 24% under imminent threat, 26% in danger
- support 1-9 million species
360
problems with reef loss
- reduced storm surge protection
- job losses
- impacts to religion/tourism
- reduced diversity
361
threats to coral
- overfishing or pollution
- overfishing -decreased herbivores -increased algae (top-down)
- pollution --nutrients --algae increase (bottom-up)
- more important to focus on water quality or fishing regulation
- find herbivores to be more important control
362
manipulative experiment trade-off
- ability to control, replicate, randomly assign treatments, reduce chance and confounding variables
- small spatial scales, controlled environments, not entirely realistic
363
positive deviance approach
- seek out samples of unusual or rare success
| - determine what these rare cases have that is lacking from other unsuccessful cases
364
how to use positive deviance research in corals
-determine what makes some species of corals thrive in warmer waters --> particular symbiont species --> focus conservation on species that contain them
365
anthropogenic mercury emissions
- smoke from burning coal
| - cometics, pharmaceuticals, dental products
366
nearly half of the world lives
within 200km of the coast
367
overharvest
harvest that exceeds productive capacity of a species and causes the pop, and consequently the yield, to decline over time
368
stock
single harvested species in a limited geographical area corresponding to jurisdictional boundaries
369
yield vs stock size and MSY
below MSY yield increasing, past MSY yield decreasing (less steeply than it increased)
370
sequential depletion
deplete one marine organism until it becomes unprofitable then move on to the next
371
collapse of all fisheries by 2048?
- discredited
| - declined in catch could have been due to fisheries management restricting harvest
372
validity of CPUE as standardization
-as pop declines, takes greater effort to capture quota
373
overcapacity
- ramping up of technological efficiency and effort beyond sustainable levels
- as stocks decrease greater effort is required which causes further depression
374
stock assessment models
use all available data to predict whether fish pop is shrinking or growing and how pop will respond to different levels/types of harvest
375
countries that utilize stock assessment models
- 36%, the other 64% lack data and resources required
- less than 350 regularly assessed w/ robust scientific methods
- largely upper-income countries
376
stock assessment in poor countries
- teach fisherman to collect simple data measures that can be used for basic calculations like spawning potential
- eg. size of fish caught, reproductive status
- may also gain local support and belief by having the fisherman collect the data
377
bycatch
- includes juveniles therefore reducing future harvests
- ca. 1.5kg of bycatch per 1kg of shrimp landed (includes turtles, seabirds, mammals)
- ca. 500,000 individuals/yr
- strongly influenced by type of gear used and location of fishing
378
most indiscriminate fishing gear
- trawl nets
- gillnets
- longlines
379
reducing bycatch
- TED
- trailing streamers behind boat to deter seabird
- close fishery when mammals are abundant
- acoustic alarms deter marine mammals
380
bycatch is primary threat to
- vaquita
- Hector's dolphin
- Mediterranean monk seal
- North Atlantic right whale
381
fishing down the food web
- collapse of predator populations followed by a shift toward smaller fish and invert. pops of lower trophic level
- fisheries then shift their attention to the lower trophic level species causing a subsequent shift to lower trophic level pops
- sequential depletion hypothesis
382
sequential depletion hypothesis
- catch of top predators will decline as mean trophic level of catch declines
- suggests that over harvest is severe and widespread
- sustainability requires immediate and drastic reduction of harvest
383
sequential addition hypothesis
- top predator catch does not need to decline, could grow as mean trophic level of catch declines
- e.g. if dietary choices or fishing gear change
- suggests top predators have not been severely depleted, rather diversity of species targets is expanding and shifting
384
sequential depletion or addition?
- appears to be sequential addition
| - except in N Atl where cod collapsed
385
solutions to the tragedy of the commons
- transform commons into privately owned areas
| - establish strong regulations with severe penalties and fines
386
species that have been moved through human activity beyond their natural range
introduced
387
intentionally introducing consumer or pathogen species to control or eliminate organisms interfering with human activity
biological control
388
biological control backfire example
- cane toads native to central, south America
- brought to Australia for sugarcane insect pest control
- became very abundant, >2000 indiv./ha
- secrete toxins in skin harmful to dogs, snakes
389
reducing backfire in biological control
make sure predator is specialized
390
propagule pressure
- frequency of introductions and quantity of organisms introduced to a site
- has to be relatively high for most introduced species to take hold
- eg. Starlings introduced at least 8 times unsuccessfully before taking hold
391
only a tiny fraction of introduced species exhibit the high rates of pop growth required to produce severe biological impacts
the tens rule
392
why the tens rule may provide false comfort
- the volume of introductions is enormous, even 10% can be quite large
- long time lags are common between import and establishment
- 10% may be too low
393
species that establish as self-perpetuating populations in their non-natural habitat
naturalized
394
species traits associated w/ invasion success
- high dispersal rate
- high rate of pop growth
- small seed size, longer viability of seed in soil
395
natural enemy release hypothesis
-absence of natural enemies give introduced species advantage over competing native species, promoting large pop size and rapid growth
396
Naturalization hypothesis
- Darwin, 1859
- introduced species are less likely to become established if other congeners are native to the recipient community
- natural competitors
- likely to have shared predators
397
species that become so abundant in their non-native habitat that they threaten habitats, ES, or native species
invasive
398
biotic resistance hypothesis
-highly diverse, undisturbed communities have lower invisibility than disturbed, low species ones
399
congener
species of the same genus
400
biotic acceptance hypothesis
- conditions good for native species also good for nonnative species
- eg. nonnative reptiles most abundant where reptiles are most abundant
- means that biodiversity hotspots might be in danger
401
important nonnative species
- crops
- livestock
- pets
- pollinators
402
nonnative species benefits
- substantial increases in PP
- increased nutrients
- facilitate growth by adapting previously harsh environments (ex. nitrogen fixers, primary succession plants after fire)
403
feral cats
- 33 extinctions (bird, reptile, mammal)
- 1.3-4 billion bird deaths/yr
- 6.3 - 22.3 billion mammals/yr
- greatest source of anthropogenic mortality of US birds and mammals
404
invasion hotspots
- areas where nonnatives are >25% of the species
| - correlated w/ high human pop. and economic activity
405
how to determine very rare species presence, especially in waterways
eDNA - environmental DNA
406
Species to focus invasion control on
predators - have much higher impact than invasive herbivores are plants
407
Improving companies environmental reputation
- report debt to nature
- carbon/water neutral
- sustainability
- partner w/ env't groups
408
biophilia
humans have an innate need for intimate association w/ nature, especially its living biota, and that this need is deeply rooted in the evolutionary history of our species
409
Video games have largely replaced the outdoor activities of many adolescents
videophilia
410
environmentalism and generation
millennials ca. 10% less likely to self-identify as environmentalists - due to less contact w/ nature?
