370 Flashcards
Are we in the midst of a sixth mass extinction study
Life threatened
Birds 13%
Mammals 25%
Amphibians 41%
The major threats to nature
- Habitat loss and degradation
- Overexploitation
- Invasive species
- Climate change
- Nitrogen depostion
other threats to nature
pollution
disease
overuse of freshwater
cumulative impacts
habitat degradation most detrimental to what kinds of species
specialists
biggest threat that invasive species have
threaten biodiversity by predation and competition
biggest threat from nitrogen deposition
ozone depletion
agriculture use
1/3 of earths ice-free land
much of the other 2/3 is not suitable for agriculture
human population growth
exponential
> 7 billion, almost 8
after 1960 +1billion/ 10-15years
Human population 2050
9-12 billion ppl
all the people on Earth could fit in
1 cubic mile
what does the volumetric size of the worlds population show us
There are really not that many humans, our choices are the problem
affluence
wealth
consumption of fuel, clothing, food, toys, etc.
affluence and population growth
wealth increases child survivorship, decreased child mortality = decreased birth rate
Demographic transition
birth/death rates vs years
pre-transition stage- Brate=Drate, pop low
early trans.- Drate plunges, Brate constant, pop starts to increase
mid transition- Brate drops, pop asymptotes
late transition- Brate=Drate lower than before, pop stabilizes
Ecological impacts of a species on its environment
Total Impact (resource use) = abundance x per-capita resource use
Can we use resources faster than they are supplied?
only by drawing down the capital, which will not last forever
IPAT model of human impact on the environment
Impact = human Population size (P) x per capita Affluence (A) x Technology factor (T)
The Kuznets Curve
environmental degradation vs per capita income
parabola, environment worsens up to turning point then improves with further income
what happens after turning point in kuznets curve
wealthy enough to invest in saving the environment
validity of kuznet hypothesis
pretty optimistic
where is the human footprint highest
terrestrially - along the coastlines, low latitudes marine - most of the worlds ocean, lowest around Antarctica
conservation science
seeks to understand human impact on species, habitats, ecosystems, and provide tools for protecting and restoring those parts of nature that we value
what is demographic transition
pattern of changes in human birth and death rates as societies become more economically developed
demography
study of population traits such as abundance, age structure, sex ratio, rates of birth and death
what happens in early stage demographic transition
births»_space; deaths due to improved living conditions, population explodes
world population growth rate
currently: 1.2%
peak: 2.1% 1965-1970
does the decreased population growth rate mean that population is not growing as much
no b/c base is increasing, growth rate is a lower % of a much larger number
population additions 1960s, now
1960: 72.5 million /yr
now: 86 mill ppl/yr
problem with IPAT model
may be viewed as anti-pop. growth and anti-consumption
tech can be + also
benefits of ecosystem change
improvements in health: increased life expectancy, reduced child mortality
access to information: increased telephone use
increased wealth
main drivers of all human impacts
- size of human population
- per capita rate of consumption
- environmental effects of the tech used
what is the role of conservation science
to determine how human disturbances are altering natural systems and predict future impacts by analyzing quantitative data
goals of conservation science
determine most effective conservation actions
provide objective discussion of consequences and trade-offs
background rate of extinction
rate between periods of mass extinctions
deep roots of conservation
Aristotle (384-322BC)
King Philip IV, France (1268-1314)
Charles Darwin (1809-1882)
King Philip IV conservation
restricted types of traps, nets, and seasons for fishing in 1289 after realizing fishermen were decreasing the amount of fish in the rivers
Charles Darwin conservation views
scientific value: “the rescue and protection of these animals is recommended less on account of their utility.. than on account of the great scientific interest attached to them.”
Important groups in 19th century American conservation
- The Romantic-Transcendental conservation ethic
- The resource conservation ethic
- The evolutionary-ecological land ethic
Romantic-transcendental conservation
The Preservationists
Henry David Thoreau
John Muir
Ralph Waldo Emerson
Preservationist beliefs
nature feeds our soul, spiritual romantic values
Thoreau
1817-1862
recognized and wrote about beauty of nature before people thought about or cared about it
Muir
1838-1941
activist
helped bring about preservation of Yosemite
Resource conservation ethic
The Conservationist
Gifford Pinchot
Conservationist beliefs
utilitarian, we should protect nature for its resources
Evolutionary-Ecological Land ethic
Aldo Leopold
recognize the need to consider systems, and relationship between parts, ties beauty and usefulness together, lead to CB as we know it
Rachel Carson
1907-1964
Silent Spring
call to arms, led to precautionary principle
precautionary principle
we should not carry out actions that could be harmful to health/ environment if the effects are not fully established
Fundamental conservation biologists, 1960-1980s
Michael Soulé
Jane Goodall
EO Wilson
David Suzuki
why did conservation biology arise
- in 1980s ecologists were concerned about human impacts
- inadequacy of existing disciplines
Conservation biology is made up of
biological science (ecology, evolution, genetics) applied science (forestry, fisheries, agriculture) physical science (climate, atmos, soil) social science (economics, law, politics, ethics)
conservation biology is a mission-oriented science
focus on how to protect and restore biodiversity, diversity of life on earth
general questions conservation biologists must answer
- how is diversity of life distributed
- what threads does diversity face
- what can be done to reduce/eliminate threats and restore diversity
Conservation Biology’s ethical principals
- Biodiversity should be preserved
- evolution should continue
- ecological complexity should be maintained
- biological diversity has intrinsic value
- people must be included in conservation planning
qualities of conservation biology
'crisis' discipline largely reactive rather than pro-active 'mission-driven' multi-disciplinary encompasses all diversity inexact science evolution time-scale
Prevailing view of conservation through time
1960-70: nature for itself
1980-90: nature despite people
2000-05: nature for people
2010: nature and people
resilience
how much we can perturb the system before it switches to a new state
NCS
new conservation science
needs of humans should be prioritized over intrinsic values
what is wrong with NCS claims
conservation already considers humans, is realistic, and has succeeded in the past
humans views change with time
Important conservation organizations
Audubon (1886) Sierra Club (1892) IUCN (1934) Ducks Unlimited (1938) The Nature Conservancy (1951) WWF (1961) Society for Conservation Biology (1985) Conservation International (1987)
Conservation Landmarks
US Endangered Species Act (1973) Rio Earth Summit (1992) Kyoto Protocol (1997) Species at risk act (2002) Earth Summit (2012)
Conservation in Canada
Control of species consumption (1800s) Banff National Park (1887) Commission of Conservation (1909) Point Pelee National Park (1919) National Parks Act (1930) COSEWIC (1977) Canadian Biodiversity strategy (1995) Species At Risk Act (2002)
Commission of Conservation, Canada
1909
efficiency of natural resource use
Point Pelee National Park
1919
focused on wildlife habitat (migratory birds) rather than commercial benefits
National Parks Acts
1930
systematic protection from development
COSEWIC
Committee on the Status of Endangered Wildlife in Canada
What role does conservation science play in protecting biodiversity
- illuminates biodiversity patterns, threats, solutions
- informs policy decisions
Policy decisions should
protect biodiversity based on economics, politics, societal values
Sciences key role in conservation
clarify: effect of current activities which actions are most effective provide: objective discussion
Pleistocene overkill hypothesis
widespread and catastrophic extinctions of large land-dwelling mammals to early human hunting
Where was Pleistocene overkill
Australia 40-70kya
NA 11kya
NZ 1kya
everywhere humans emigrated
extinctions ‘known’ to be directly from hunting
dod
stellar’s sea cow
caribbean monk seal
passenger pigeon
functionally extinct
no longer serving the ecological role they once did
example of functionally extinct species
American Bison
Major habitats lost (>40%)
mediterranean woodlands
temperate grasslands
temperate broadleaf forests
Conservation in Canada has historically been
utilitarian
biodiversity
- variability among organisms and the ecological complexes they are part of
- diversity within species, between species, of ecosystems
compositional levels of biodiversity
genetic diversity
species diversity
community/ecosystems diversity
Hierarchical components of biodiversity
3 nested groups: compositional, structural, functional
structural component of biodiversity
genetic, population, habitat structure, landscape patterns
Compositional component of biodiversity
genes
species, populations
communities, ecosystems
landscape types
functional component of biodiversity
genetic processes
demographic processes, life histories
interspecific interaction, ecosystem processes
landscape processes, disturbances
components of biodiversity the public responds to the most
compositional - genes, species, populations, communities, ecosystems
fundamental unit of conservation
generally the species
biological species definition
a group of individuals that interbreed in the wild to produce viable, fertile, offspring
problem with biological species definition
some ‘non-natural’ groups breed and produce fertile offspring
ex. Red Wolf (maybe)
asexual producers
morphological species definition
morphologically, physiologically, biochemically distinct from other groups in some important characteristic
problems with morphological species definition
some species have huge variation (dogs, humans)
cryptic species
phylogenetic species concept
because of relatedness share at least one morphological or molecular trait that is absent in other potentially related groups
problem with cryptic species
can mask threats to 1 species if 2+ are thought to be the same
Number of named species on Earth
ca. 2 million
> 1.5 mill
number of species described per year
ca. 18,000/yr
How many species are there on Earth
3-30million
best estimate ca. 5million ± 3
most specious taxa on earth
insects - estimated to be nearly 1 million
Lesula
a new species of monkey described in 2012 from congo
even vertebrates are still being discovered
best described taxa on earth
Plantae! easy to see, don’t move around
synonymy =
taxonomic inflation
taxonomic inflation
looks like there are more species than there are b/c some species are named more than ones
% of taxa likely to be synonyms
- 9% species
7. 4% genus
why does synonymy occur
large range species generalists intra-specific variation poor communication between scientists few/poor reference collections phenotypic plasticity
example of synonymy
European mussel
Anodonta cygnea
described 549 times!
species accumulation curve
# species vs # of samples when graph starts to asymptote then getting close to the true number of species
most well known biodiversity pattern
biodiv inversely proportional to latitude
species increase towards equator
seen in amphibians, plants, fish, endemics, bivalves, corals, mangroves, seagrasses
where are endemic species highest
low latitudes
islands, isolated ecosystems
general biodiversity patterns
- Latitudinal diversity gradient
- species-energy relationship
- species-area relationship
latitudinal diversity gradient
species richness vs latitude
parabola, increasing from -90 - 0, hump, decreasing from 0 -90º
species-energy relationship
sun –> energy –> PP –> more species
SR vs evapotranspiration
increasing power function
evapotranspiration
water transfer from soil to atmosphere by plant transpiration
proxy for productivity
species-area relationship
# species vs area increasing exponential fn more space = more complex relationships, more room for large animals
diversity and scales
relationships can vary based on scale
local patterns may not reflect the larger scale pattern
result of species-area hypothesis
tropics are largest biome
relates to latitudinal diversity gradients
results of species-climate stability hypothesis
tropics have more stable climate
relates to latitudinal diversity gradient
results of species- climate harshness hypothesis
few species can tolerate cold
relates to latitudinal diversity gradient
results of species energy hypothesis
tropics have greatest productivity
relates to latitudinal diversity gradient
hypotheses that support latitudinal-diversity gradient
species-area Ho
species-climate stability Ho
Species-climate harshness Ho
Species-energy Ho
what is a stable habitat
- stable in physicochemical characteristic - temp, precipitation
- stable through time
why are tropics stable through time
low latitudes are less likely to be covered and ‘reset’ by glaciations
species diversity
number and relative frequencies of species in a given community
ways to describe species diversity
species richness
species evenness
species evenness
equitability of abundance across species
why local diversity patterns may show increased diversity
addition of invasives
homogenization
biodiversity crisis is homogenizing the world because generalists and species with large ranges have the advantage
Three types of species diversity
Alpha diversity
Beta diversity
Gamma diversity
importance of diveristy
buffers attacks to survivability
increases resilience
% polymorphic loci
a measure of genetic diversity
ex. rats have very high genetic diversity - high resilience
Alpha diversity
species we find in one specific place
local, within
eg. Saanich Peninsula
Beta diversity
species we find in an entire region
within, larger scale
eg. VI
Gamma diversity
difference in species between two places
eg. differences between Saanich Peninsula and Strathcona Park
focusing on species protection
may miss out on important environments, related organisms
units to protect
species, biome, ecoregion
ecoregion
large area characterized by similar mix of environmental conditions that contains relatively distinct flora and fauna
major ecoregion of the world
oceania realm nootropic realm afrotropic realm antarctic realm indo-malay realm australasia realm nearctic realm palearctic realm
Major biomes of the world
tropical rain forest tropical seasonal forest/ savannah woodland/shrubland temperate grassland/ desert boreal forest subtropic desert temperate rain forest temperate seasonal forest tundra alpine polar ice cap
Large marine ecosystems
regions of ocean encompassing coastal areas out to edge of continental shelves
ca. 200,000 km2
large marine ecosystems are characterized by distinct
bathymetry
hydrography
productivity
tropically dependent populations
values of biodiversity
intrinsic value
instrumental value
intrinsic value
biodiversity is valuable independent of its value to humans
organisms have a right to survive
instrumental value
humans value of biodiversity
types of instrumental biodiversity value
Aesthetic, cultural, spiritual Goods water/air purification, flood control, pollination recreational education, informational
biodiversity goods uses
consumptive use
productive use
what is consumptive use
goods used directly by local communities and invisible to GDP
hard to quantify, attach value to
eg. food, fiber, medicine, fuel
raw products, oxygen
productive use
value added goods, ‘in the system’, visible to GDP
finished foods and material , sold in a market
problem with intrinsic value
difficult to convince people of!
bioprospecting
sample, extract, study, test, unstudied organisms (plants) for value
biological mining
plant species that have led to drug discoveries
1/125
% of pharmaceuticals based on organism products
79%
based on plants, fungi, bacteria, verts
how many plant species have been examined for medicinal properties
less than 0.5%
examples of plants leading to medicinal discoveries
Willow (Salix spp) -- Acetylsalicylic acid Pacific yew (Taxus brevifolia) -- Taxol cancer treatment
Ideas behind instrumental valuation of biodiversity
adding value to biodiversity in order to get people to ‘buy in to conservation’
ecosystem services
essential goods, service, natural ecosystems deliver to people
Types of marine ecosystem services
Provisioning services
regulating devices
cultural services
supporting services
marine ecosystem provisioning services
seafood
timber, fiber
pharmaceuticals
marine ecosystem, regulating services
water quality control
climate regulation
marine ecosystem, cultural services
tourism, recreation
aesthetics, spiritual values
marine ecosystem, supporting services
nursery habitats
marine and terrestrial ecosystem link
Earth system, tightly linked, support each other
eg. salmon - river- riparian - forest
habitat loss concerns
leading cause of extinctions/ endangerment
loss of beauty, rec, inspiration
important roles
what roles do habitats play
carbon sequestration
reduce flooding
storme surge protection
maintain soils
problems with invasive species
weeds insect pests vectors of disease clog waterways change fire frequency alter ecosystem processes global homogenization
changes in CO2
1960 - 280ppm
2013 - 395ppm
now - 0ver 400
increase 0.5-1% /yr
changes in world temperature
1951-2012 0.12ºC increase / decade
shifts in spring behaviours
2-3 day shift / decade
species range shifts
poleword 10km/ day
other climate change impacts
nitrogen cycle alteration O3 depletion acid rain algal blooms eutrophication anoxia
anthropocene
an era in which anthropogenic impacts dominate
cryptic species effect on species number
if not recognized than species # lower
once recognized species # increased
recognized more now with DNA analysis
Largest extinction
P-T, 250Mya, formation of Pangaea, 96% of species lost
trait most strongly associated with extinction
body size
KT extinction
65Mya
dinosaur extinction
start of age of mammals
species at greatest risk
specialists - limited resources
endemics - limited habitat
with accelerated extinction levels what should we expect to see in the future
small bodied, widespread, generalist species
hybridization occurs most
in endangered populations
generally leads to lower fitness
insurance
biodiversity
negative externalities
environmental harm/damage from exploitation that impacts others who had no choice in the matter
problems with ES and negative externalities
human-centered, no biodiversity focus
can be seen as disingenuous
can backfire
what should we conserve
particular species, number of species, endemics, threatened species, number of ecosystems, threatened or special ecosystems, biodiversity hotspots, evolutionary uniqueness
biodiversity hotspots
> 2500 endemic plant species
70% loss of original habitat
eg madagascar
Madagascar
90% loss of rainforest
12,000 endemic plant species
problem with conserving hotspots
narrow focus on species richness and threat
whole ecosystems can be overlooked
ignores cost effectiveness and feasibility
spatial scale
incongruence
species richness, hotspots, endemism, threats do not always line up
some conservation frameworks
biodiversity hotspots crisis ecoregion endemic bird areas megadiversity countries WWFs global 200 high-biodiversity wild frontier forests last of the wild
aligning conservation frameworks
Irreplaceability vs. vulnerability
low vulnerability = proactive approach
high vulnerability = reactive approach
“Last of the Wild” conservation framework
Wildlife conservation society
areas with lowest human ecological footprint
less likely to obscure by conflicts and proposals of human infrastructure, may maintain status for long time
conservation funding
90% of the $6B of funding originates in and is spent in economically rich countries
ca. $600 million ‘flexible’ funds
prioritization schemes important for
justifying and obtaining funding
focal species
flagship species umbrella species indicator species keystone species dominant species foundation species ecosystem engineer
flagship species
‘easy’ to protect, special charismatic or cultural value
strategic concept for raising public awareness and financial support
often: large, ferocious, cuddly, cute
umbrella species
conservation of an organism protects a number of others, typically have large or unique habitat needs
Indicator species
most sensitive to perturbation or habitat-of-concern, canary in the coal mine
keystone species
species whose impact on its ecosystem is disproportionately large relative to its abundance
dominant species
species with large impact on ecosystem because of its high abundance
example of flagship species
panda
example of umbrella species
grizzly bear, if we seek to conserve their habitat it is a large area of forest that could also protect others like owls and even the plants
example of indicator species
owls
importance of indicator species
they tell us about the health of the ecosystem
keystone species example
sea otter - kelp - sea urchin
example of dominant species
bunny
bison
foundation species
dominant autotrophs the rest of the ecosystem depends upon
foundation species example
kelp
pines
sea grass
mangroves
ecosystem engineer
species that modifies the habitat in a way that impacts others
example of ecosystem engineer
beaver
elephant
example of evolutionary uniqueness
Tuatara
other protection units
unique biological processes (ex monarchs)
migratory routes
what to protect if focused on ecosystem function
the ecosystem, some % of species everywhere, not focus on biodiversity or certain species
what factor is consistently overlooked in conservation prioritization
COST
feasibility
return on investment
cost
-purchase
-management
costs can vary more than diversity
feasibility
governance, law and order, corruption
peace
capacity (literacy, education)
Wildlife Conservation Societies ‘global priority species’
broad geographic range evolutionarily distinctive ecologically important important to humans need conservation action
prioritization schemes typically based upon
some measures of biodiversity and threat often in a framework of vulnerability and irreplaceability, may be be proactive or reactive, individual and subjective
prioritization scheme pro
proven useful in mobilizing funding
prioritization scheme con
do not make best use of conservation $$, do not factor in ROI (return on investment)
to maximize conservation success
biological factors, cost, and feasibility must be taken into account
globally extinct
no individuals remain anywhere in the world
extinct in the wild
individuals of the species occur only in captivity
at least 68 spp
regional/local extinction
loss of species from part of its former geographic range
extirpation
purposeful disappearance (often wrongly used to mean local extinction)
example of extirpation
basking shark
sea otter
impact of local extinctions
often lead to global extinctions
can cause extinction of other species in ecosystem
species are interconnected
why to be concerned about local extinctions
populations are unique (genetically, behaviourally, morphologically)
impacts and management often occur at population scale
disappearance of populations precedes global extinction
more subspecies =
higher chance of species survival
co-extinction
an extinction that occurs alongside extinction of a focal species
co-extinctions most commonly in
specialist parasites
ex. passenger pigeon louse, tropical butterfly and host plants
ecological / functional extinction
the reduction of a species to such low abundance that it no longer interacts significantly with other species or performs its ecosystem function
proving extinction
very difficult, easy to miss, require exhaustive surveying, can get it wrong
possibly extinct
likely but a chance they are extant
Lazarus effect / Romeo error
declared extinct when they actually aren’t
why does lazarus effects occur
not enough money for in depth survey
difficult to find every last individual
example of lazarus effect
Cebu flowerpecker declared extinct in 1950s, found in 1992 (86 yrs with no record!)
when are extinctions typically discovered
long after, often >75yrs
few species with every individual monitored
other problem with extinctions
many go unnoticed, especially small, inconspicuous species
number of species extinction per year
ca. 27,000
74/yr
3/hour
EO Wilson
commercial extinction
overexploitation of a target species to the point that it is so low and sparse that it is no longer worth targeting, often assumed safe from biological extinction but often not
examples of commercial extinction
bluefin tuna
abelone
atlantic cod
species average lifespan
1-10MY
example of ecological extinction
oysters in Chesapeake bay, population overexploited, reduced water filtering potential
what is the background extinction rate
0.1-1 species/ million species / year
current best estimate of # of species on earth
ca. 10M
what would background extinction be now based on best estimate of number of species on earth
1-10 species / year
current actual extinction rate
100 (known) extinctions / 210000 species / 100 years
1 ext. / 21,000 species / yr
47.6 ext. / mill species / yr
ca. 50-500X the background rate
ecosystem services
essential goods and services ranging from medicines and building materials to soils, water, flood control, that natural ecosystems deliver to ppl
MEA
Millenium Ecosystem Assessment (2005)
1300 scientists, 95 countries determine that humans interfere on such a huge scale that human well-being is at risk, and the ppl most at risk are the rural poor
protect natural vegetation?
may not be high biodiversity but may protect ecosystems and decrease catastrophes, loss of marshes exacerbated the effects of Katrina
rivot hypothesis
a few losses will not impact the system but many losses will result in loss of function
portfolio effect
stability-diversity relationship, diversified portfolio so that gains can offset the losses – net stability
portfolio effect in a single species
plasticity of subpopulations
why do people degrade the environment
economic incentive
economic valuation
assigning value of services and their negative externalities to make degradation more apparent, may increase sustainability decisions, difficult to assess
willingness to pay
maximum stated price an individual would pay to avoid loss or reduction of ES
PES
Payments for Ecosystem Services
reward land owners for conserving/ restoring ES
example of PES
water funds
grains to green program
serviceshed
area where an ecosystem service is generated and where people benefit from it
InVEST
Integrated Valuation of Environmental Service and Tradeoffs
map services, provide quantitative data to help conservationists compare areas/efforts and make decisions
conservation market
if a market exists, conservation will result in benefits for biodiversity and economics
ex. carbon sequestration, reforestation
Is ES approach the right way to go
may undervalue intrinsic values
best approach incorporates ES + regulations + ethical appeal
marine species extinctions
18 marine species listed as extinct on IUCN 2013 list
no known fish -too difficult to document
Great auk
flightless, islander
Atlantic, last known from 1852
extinction debt
habitat destruction compromises species range, not resulting in complete and immediate extinction, but eventual extinction;
extinctions occur generations after fragmentation;
future ecological cost of current habitat destruction
Time lag
individuals persist for long periods of time in lower quality habitat fragments, populations slowly spiral to extinction
most threatened taxa
% threatened gymnosperms - 36% fishes - 37% reptiles - 31% amphibians - 30%
Vulnerability to extinction
V = ES vulnerability = extrinsic threatening process x intrinsic sensitivity
Main correlates of extinction
- Large body size
- Small geographic range
- Specialization
body size and extinction
low intrinsic rate of pop increase
high trophic level
smaller pop size
intrinsic rate of increase
rate a population increases in size if there are no density-dependent forces regulating the population, births - death per generation
small geographic range and extinction
island populations
mountain/ peninsula species
single location endemics
why do islands have large number of endemics
evolutionary isolation
examples of island extinctions
Stephen’s island wren, NZ
17 extinct lemurs, Madagascar
specialization and extinction, ecological specialism
Habitat specialization Diet specialization ex. panda bear Diadromy Flightlessness
diadromy
migration of fish in either direction, from fresh to sea water reverse
examples of diadromy
salmon
eels
sturgeons
total abundance vs index of specialization
exponential increase
generalists»_space; abundance than specialists
NZ Moa
10-11 species of flightless endemic bird
died 700-400BP
co-extinction with Haast’s eagle
why model
nature is complex (simplify)
models help clarify our thinking (understand)
models generate testable predictions (forecast)
models provide insight into the systems they mimic
problem with models
abstract representations, not always accurate,
nature doesn’t have to follow natures, do not rely to heavily on them
Why is EO Wilson’s extinction rate so high
extinctions are very slow, not all known
Estimating extinction risk
read species area curve backwards
species area curve function
S = c A^z S = species c = constant A = area z = rate of species accumulation
number of biodiversity hotspots
25
CRI
conservation risk index
fraction of habitat protected : fraction of habitat converted
unique habitats not protected if only focused on biodiversity
Yellowstone
Hydrothermal vents
marshes
Conservation planning process
- ID conservation target
- Inventory region for targets and threats
- Set conservation goals
- Design network of conservation areas
Conservation goals
specific, measurable, quantifiable, needed to measure success, adjustable
how much is needed to sustain population
important to include in planning
costs
objectives
species shifts
ES vs biodiversity
not correlated but should try to find sites that rank high for both
example of including multiple priorities in conservation plan
Florida - planned to reduce storm surge, included important habitat, areas of flood risk, vulnerable human population, threatened/ endangered species
species lost at 50% habitat loss
10% species loss
species lost at 90% habitat loss
50% species loss
If we lose half the area of an island, what proportion of species do we expect to lose (assuming c = 4, z = 0.2)
S = cA^z
12%
% species lost with 50% habitat destroyed vs z
increasing
higher z = higher species losses
Singapore species loss
95% of forest lost over 180 years
30% loss of forest species
32% of native birds lost
Assumptions of SAC estimates
- habitat loss instantaneously eliminates species
- habitats are lost (in reality often converted)
- Habitat loss is random with respect to SR / habitat quality
- Individual vs. the whole
- extinction rates are unaffected by fragmentation of remaining habitat
- other threats
why does S-A approach consistently overestimate the actual rate of extinction
space that must be searched to find single individual of species smaller than space that has to be searched to find every last individual of that species - going backwards is not the same as going forwards
why are marine ecoregion based on seafloor environment
species distribution is challenging to map and knowledge is limited compared to land
biodiversity offsets
form of mitigation in which loss of biodiversity at one site is compensated for (offset) by protecting another area
common conservation mistakes
- not labelling plan as prioritization
- too vague of definitions
- too much attention to places over actions
- arbitrary indices
- not incorporating risk of failure
z is SAC depends on
isolation, connectivity, migration / movements
high isolation = large z
small populations =
larger extinction threat
IUCN
International union for conservation of nature;
only official global list of species at risk; 8 categories
IUCN Categories
Extinct extinct in the wild critically endangered endangered vulnerable near threatened least concern
extinction vortex
extrinsic factors – population shrink – small, isolated population, inbreeding and drift reduce genetic variability and individual fitness – population declines – demographic / environmental stochasticity, allee effect – reduced population – repeat downward spiral –
extrinsic factors that shrink population
habitat destruction
pollution
over harvest
invasive species
overall extinction vortex pattern
small pop – low genetic variability – lower survival, lower reproduction – small pop – downward spiral to extinction
Allee effect
correlation between pop size/density and mean individual fitness
demographic stochasticity
variability of pop growth rates arising from related random events
ex. birth rates, death rates, sex ratio, dispersal
environmental stochasticity
unpredictable fluctuations in environment conditions; one of main sources of fluctuation in ecological processes; cause pop fluctuations
inbreeding =
increased homozygosity = reduced fitness
effects of fragmentation, Chiew Lam reservoir
native smal mammals disappeared rapidly, after 25 yrs small mammals almost gone from 16 islands, SR most correlated to area
modeling population change over time
BIDE
BIDE
N_t+1 = N_t + Births + Immigrants - Deaths - Emigrants
modelling discrete population growth
exponential growth, closed population, BR/DR constant, growth by same factor each year- not truly continuous
discrete population growth function
N_t+1 = N_t *λ
discrete population growth rate, λ =
N_t+1 / N_t
exponential population growth beyond one year
N_t = N_o * λ^t
λ = (N_t /
N_o) ^ 1/t
effect of λ on population growth
λ > 1 - population growth is exponential
λ = 1, pop is stable
λ less than 1, pop declines
continuous population growth
dN/dt = (b-d)N dN/dt = rN Nt = N_o *e^rt
r
per capita intrinsic rate of increase
r > 0, pop increases exponentially
r = 0, pop constant
r less than 0, pop decreases exponentially
Doubling time
a population growing exponentially has a constant doubling time
t_d =
ln2/r
λ =
e^r
r =
ln(λ)
advantages of λ
technically more accurate for discretely growing pop’s; can be intuitive; translates easily into % annual growth
If λ = 1.20
population growing at 20% / yr
advantages of r
entered around 0 (symmetric)
**Scales
inbreeding
increases frequency of deleterious alleles
what happens when capital is drawn down
no buffer
exponential population growth assumptions
population closed (NO I, E) constant B/D rates; deterministic No age or size structure
Allee effects
survival and reproductive success of each individual declines in a deterministic manner as pop. declines; at low density pop growth is hindered; individuals benefit from having conspecifics
deterministic system
system in which no randomness is involved in the development of future states of the system
Allee effects: mechanisms
minimize predation
foraging advantage
reproductive success
conditioning of environment
how allee effect minimizes predation
detection and defense
predator swamping
anti-predator aggression
how allee effect creates foraging advantage
access to food
social hunters
cooperative resources defense
how allee effect increases reproductive success
obligate cooperative breeders
finding mates
why are rare alleles less likely to be expressed
more often present as heterozygotes, inbreeding increases homozygosity
species area overestimates extinction how much
estimated rates nearly double actual rate
results of sea turtle functional extinction
ecological collapse of seagrass beds
red listed species
vulnerable - high risk
endangered - very high risk
critically endangered - extremely high risk
density independent population change
pop shrinks or grows at a constant rate regardless of how sparse or crowded it becomes, i.e. resources are unlimited no matter how large and no problems finding mates/ resources when pop shrinks
deterministic population dynamics
there are no ‘good years’ and ‘bad years’, environment is constant (resource availability, predation, disease, disturbance), i.e. no environmental stochasticity
homogeneous individuals
all individuals have same reproductive success and same probability of survival and growth (i.e. no demographic stochasticity)
If a population grows by 30% (λ=1.3) one year and shrinks by 30% (λ=0.7) the next year
does not sum up to net = o
λ = 1.3 of No =100 results in 130
λ = 0.7 of No =130 results in Nt = 91
overall λ = 0.95, geometric mean (GM)
GM =
square root (product of λ_i’s)
stochasticity
randomness or uncertainty
demographic stochasticity
if a pop has few individuals chance variations in the sex ratio of offspring or the survival and reproductive success of individuals can prevail over what is expected on average
positive correlation between population size and individual success
allee effect
impact of geographic range on environmental stochasticity
smal range = higher chance of entire species being wiped out by one event
