Midterm 1 Flashcards
Why Conservation
Biology?
Because we have to.
-even a slight increase in temp can have detrimental effects on our planet (Australia bush fires, melting of the Himalayan glaciers- where we get a lot of our fresh water, many homes lost to flooding leading to millions of refugees, droughts- shortages in global grain and meat markets(have to feed the herds and fertile ranch land turns to desert), hurricanes)
• >83% of the Earth bears our ‘ecological footprint’
• 98% of fertile lands have been transformed
->vast majority of populations and species of plants and animals – key working parts of human life support systems – are in decline, and many are already extinct.”
What is Conservation Biology?
• emerged in the mid-1980s
• New field focused on understanding, protecting,
and perpetuating biological diversity at all scales
and all levels of biological organization.
• Emergence reflects more recent developments in
an array of biological sciences (ecology, genetics,
evolutionary biology, etc.) and natural resource
management fields (forestry, wildlife and fisheries
management, etc.
- It was conceived as a “mission- oriented” field based discipline in the biological sciences
what is a COSEWIC report?
COSEWIC (Committee on the Status of Endangered Wildlife in Canada) bases its status assessments primarily on status reports. A status report is a comprehensive technical report that compiles and analyzes the best available information on a wildlife species’ status in Canada and indicates the threats to that wildlife species1.
what is SARA? how is the government involved?
Species at Risk Act
•Key tool for conservation and protection of Canada’s biological diversity
->provides legal protection for species at risk will
complement existing legislation
• Government of Canada is committed to
conserving biological diversity and to the
principle that,
– if there are threats of serious or irreversible damage
to a wildlife species, cost-effective measures to
prevent the reduction or loss of the species should
not be postponed for a lack of full scientific certainty
– this responsibility is shared among governments
within Canada
-> It is a piece of Canadian federal legislation which became law in Canada on December 12, 2002. It is designed to meet one of Canada’s key commitments under the International Convention on Biological Diversity.
what is the purpose of SARA?
*The goal of the Act is to protect endangered or threatened organisms and their habitats
– To prevent wildlife species from being extirpated
or becoming extinct
– To provide for the recovery of wildlife species that
are extirpated, endangered or threatened as a
result of human activity
– To manage species of special concern to prevent
them from becoming endangered or threatened
Scope of SARA?
• listed aquatic species and their critical habitat
• listed migratory birds and their critical habitat
• other listed species and their critical habitat on:
• federal lands
• provincial and territorial lands if “safety net” is used
ex: The B.C. government has approved the shooting of one species of owl in a last-ditch effort to save their endangered cousins, as the number of northern spotted owls continues to decline
SARA–elements ?
- Stewardship
- Science based species assessment by COSEWIC
- Listing process
- Protection measures
- Public participation
- Enforcement measures
- Offences and punishment
- Alternative measures
- Public registry
- SARA: Stewardship
• Stewardship action plan
• Conservation agreements with any government,
organization or person for measures to:
– protect species at risk and their critical habitats
– develop and implement recovery strategies, action
plans and management plans
– conserve wildlife species not at risk, to prevent them
from becoming “at risk”
• Funding agreements to help cover costs of
conservation actions
- SARA: science based species assessment
• Assessment must be based on status reports
Gives COSEWIC legal basis as it is not a legal report on its own but it can trigger legal action (via SARA)
– Uses the best available biological information
• Scientific knowledge
• Community knowledge
• Aboriginal traditional knowledge
COSEWIC must assess within 1 year after it receives a
status report
what is the CESCC?
CESCC (Canadian Endangered Species
Conservation Council)
=Minister of the Environment, the Minister of
Fisheries and Oceans, the Minister responsible for
the Parks Canada Agency and ministers of the
government of a province or a territory who are
responsible for the conservation and management of
a wildlife species in that province or territory
- SARA: listing process
the minister of the environment receives species assessments from COSEIWC at least once per year and then publishes a response statement on the SARA public registry where he or she indicates how they will respond to the assessment and sometimes give a timeline for action. The minister of the environment forwards the assessments to the government of council (which is also the minister of the environment) for receipt and they decide whether or not to list the species under schedule 1 of SARA or refer the assessment back to COSEWIC for further info or consideration. once a species has been added to schedule 1, it benefits from the applicable provisions of SARA
what is an Emergency Listing?
• If there is an imminent threat to the survival
of a species
– any person may apply to COSEWIC for an
assessment of the threat, or
– the Minister may make a recommendation to the
GiC to List the species as an endangered species
• As soon as possible after listing, COSEWIC
must have a status report prepared
- SARA: Protection Measures
• General Prohibitions- No harming wildlife species listed as extirpated, endangered or threatened or their home
• Mandatory Recovery Planning-co-operation
with other orders of government, wildlife management
boards, aboriginal organizations, consultation with landowners, etc.
– Identification of the threats to the survival of the
species and to its habitat
– Broad strategy to address those threats
– Measures to protect the species’ critical habitat
- Protection of Critical Habitat
- Agreements and Permits
- Project Review
- Emergency Orders
- Exceptions
- SARA: Public participation
Anyone has a right to:
– apply to COSEWIC for an assessment of
• the status of a species
• the threat (for the purpose of having the species listed
as endangered on an emergency basis)
– comment on proposed recovery strategies, action
plans and management plans prior to their
approval
why are some species left out from being listed? which ones?
there are biases in which species get listed:
marine fishes and Nunavut species rarely listed as well as species that are subject to recreational, commercial or aboriginal harvest
what is the SARA sieve?
out of the 384 species that are listed under SARA needing recovery plans, only 6 (2% of 384) have action plans.
it reflects incomplete and ineffective implantation (not limitations within the legislation)
->puts into question, are species better off with SARA or without? is SARA working?
-> To date there are now 59 finalized plans
• 5 Delayed • 15 Finalization delayed
IUCN?
• International Union for the Conservation of Nature –
– helps the world find pragmatic solutions to our most pressing environment and development challenges
how is the IUCN used?
->guide scientific research
->inform policy and conventions
-> shows where action needs to be taken tp save the building blocks of nature from extinction
• Informs Resource Allocation
• Informs Conservation Planning
• Improves Decision-making
• Increases awareness and education
what is CITES
convention on international trade in endangered species
• CITES is an international agreement to which
States (countries) adhere voluntarily
• There are now 177 states/parties to the
convention
• The species covered by CITES are listed in three
Appendices
– according to the degree of protection they need.
describe the 3 appendices of CITES
– Appendix I includes species threatened with extinction.
• Trade in specimens of these species is permitted only in
exceptional circumstances.
– Appendix II includes species not necessarily threatened
with extinction
• however trade must be controlled in order to avoid utilization incompatible with their survival.
• III
– contains species that are protected in at least one
country, which has asked other CITES Parties for
assistance in controlling the trade
define Biodiversity and list the three basic levels of biodiversity
the variability among living things from all sources
- genetic diversity- populations, individuals, chomos, genes, nucleotides
- Ecological diversity- biogeographic realms, bioms, provinces, ecosystems, habitats, populations
- organismal diversity- domains/kingdom, phyla, families, genera, species, subspecies, populations, individuals
what is Genetic diversity?
• encompasses the components of the genetic coding that structures organisms
– Nucleotides, genes, chromosomes
• variation in the genetic make-up between individuals within population and between populations
->The raw material on which evolutionary
processes act.
describe genetic diversity at the gene level
- Different alleles are created by mutations
- Mutations are rare
- Can affect protein structure or not (silent)
- Generally deleterious
describe genetic diversity at the Chromosome level
- Many versions of chromosomes are running around in a population
- New combinations of alleles are created by recombination, typically during meiosis
- Endless combinations
As a result of these processes, all individuals are different
why does fitness of individuals increase with
heterozygosity? *Significance of gen. diversity within individuals
- Heterozygotes do better: hybrid vigour
- Two versions of a gene (or protein) gives greater
flexibility (different versions of a protein help in changing
conditions) - Bad alleles can be compensated for by the better
version - Some alleles on different loci work better together
what is genetic diversity within-population level
Definition: All the organisms of the same species living in the same geographic area and have the possibility of inter-breeding
- Distribution of the genetic diversity among the individuals of the population
what are the forms and origins of within-individual genetic diversity
forms: different versions (alleles) of a gene on a locus (heterozygote)
origins: mutations and sexual reproduction
what are the forms and origins of Genetic diversity
Within-population level?
forms:
- Number of polymorphic loci (locus with 2 or more alleles and allows for multiple possible genotypes and phenotypes )
- Heterozygosity
- Number of alleles for polymorphic loci (# of alleles per locus)
origins: - Gene flow
- Mutations
how/why does population size relate to genetic diversity within population? give example
Heterozygosity/allele diversity go up with increasing population size
ex. Halocarpus bidwillii- the larger the population is, anticipated polymorphism (polymorphic loci), heterozygosity and allele number to go up
Ex common shrew- habitat for many species are being fragmented and lead to a reduction in genetic diversity as it leads to inbreeding-> Shew species are separated on the islands compared to the mainland and have less genetic diversity as a result.
Diversity increases with population size because:
1) Genetic drift and 2) bottlenecks and founder effects
what is genetic drift?
Genetic drift is a change in the frequency of an allele within a population over time. This change in the frequency of the allele or gene variation must occur randomly in order for genetic drift to occur.
( random change in allele frequency due to ‘sampling error’ during reproduction/ random changes in reproduction of the population)
- Especially important in small populations
- Results in allele loss
**2 types: bottleneck effect and founder effect (Population crashes and populations founded by a few
individuals will have reduced genetic diversity AND Strength of the effect will be proportional to the number
of survivors or the number of founders)
compare genetic drift in small and large populations
- > The small population is more vulnerable to genetic drift as the random event has more chance to cause more change from the original compared to in the large population *There werent many representatives there in the first place (Don’t see as much genetic drift in the bigger population)
- could have less genetic diversity in the population for random reasons
what is the bottleneck effect?
you have some major disaster or event that kills off most of the population with few that survive by random chance (many of the alleles may have disappeared)
-if few survivors, even more chance of genetic drift as there is a smaller population
what is the founder effect?
effect because of the founders of an area. if some leave an area to go to another area, the founders of the new area may not be representative of all the alleles from their original area. if few founders, even more chance of genetic drift as there is a smaller population
what is Inbreeding depression?
*Within-population significance
populations at low levels of genetic diversity do poorly
- Possibility to adapt to a changing environment
Bigger, more diverse populations perform
better because ?
1) no inbreeding depression and
2) better equipped to cope with changing conditions
describe genetic diversity Among populations
Variation in the number of alleles present and the
frequency of different alleles among populations
Gene flow vs Connectivity? good or bad?
gene flow= migration of genes between populations
Connectivity= migration of individuals between populations
shrew- Fst values range from 0-1 (1= genetically dissimilar), the further they get away, the less genetically similar to each other (high Fst value)
•For small populations, gene flow is beneficial and help prevent problems associated with small effective population sizes.
•For already well differentiated populations, that are
already adapted to local conditions, gene flow can be
deleterious. Outbreeding depression
how does the dispersal ability of a species influence between population level of genetic differentiation?
more dispersion/more mobile -> more gene flow -» less genetic differentiation between populations
what other factors may influence the genetic differentiation between populations?
- Structure of the habitat (or habitat patches)
influences connectivity.
->Barriers (rivers, roads, mountain ranges, etc…) increase differentiation and corridors decrease it.
what is outbreeding depression? example?
when crosses between two genetically distant groups or populations results in a reduction of fitness
ex: Capra ibex ibex, hunted to extinction, Later mixed with
subspecies from Turkey and Sinai and the hybrids gave birth in the middle of the winter (not adaptive)-> Went extinct again!!!
what is the Genetic diversity Among populations Significance?
- Different isolated populations are adapted to different
environmental conditions; thus increase the ability of a
species to cope with changing conditions - Population isolation is ultimately the source of new
species - Local adaptation and eventual source of new species. But, for small populations , gene flow is a good thing.
what are the forms, origins and patterns of genetic diversity among populations?
- Forms: variability in number and frequency of alleles
between populations - Origins: population isolation
- Patterns: Disconnected populations (through low
mobility, barriers, etc…) differ more
Biological definition of species? what is the problem of that definition?
groups of actually or potentially interbreeding natural populations, which are reproductively isolated from other such groups
Problems:
-hybrids (ex. liger)
-potential interbreeding is hard to evaluate
-some species reproduce asexually
what are the origins of species diversity?
Number of species changes over time as a function of relative importance of speciation and extinction rates
->Catastrophic events increase extinction rate, which can
surpass speciation rate: mass extinctions
why is it difficult to know how many species there are?
- There are places that are hard to explore (ex. high in the trees)
- there are new ecosystems
- there are cryptic species (many different species that look like the same species *think insects)
- poor knowledge
describe the ways to quantify and compare species diversity (3 types of diversity)
****MIDTERM****
1) Alpha (α) diversity: the number of species found
within a specified small area (study area)
2) Gamma (γ) diversity: the number of species found
within a wide geographic area (entire landscape)
3) Beta (β) diversity: rate of change in number of
species as one moves from area to area:
Beta = Gamma / Alpha
compare alpha and beta diversity in a landscape with species that are locally and widely distributed (where gamma diversity is the same in both landscapes)
**MIDTERM*
locally distributed landscape: has a low alpha diversity and a high beta diversity (specialists)
widely distributed landscape: has high alpha diversity and low beta diversity (generalists)
describe the parameters for the Species-area relationship equation -> S = cA^z
S is number of species, A is the area sampled and c and z are parameters to be estimated
->Log10 scale of equation gives a linear relationship
Y= a X + b (where b = log(c) and a=z)
->Species area relationships: Important for a management tools (ex. How big to make a park, to protect the sp.)
Simpson diversity index?
another species diversity indices-> considers the abundance of individuals of each species
-> pi is the proportion of total number of individuals
belonging to species i, and S is the total number of
species
->Ranges from 0 to 1: 0 being more diverse
*No index is perfect and a combination of many is the most
informative
describe the factor of solar energy in latitudinal patterns of species diversity
More light in the tropics would result in higher primary productivity, which in turn could support a wider range of species. But productivity not always = diversity
describe the factor of area relationship in latitudinal patterns of species diversity
There is more space under tropical climate than other colder climate. Thus, more space = more species because lower extinction and higher speciation rates. But other biomes have equal area.
describe the factor of climate harshness and stability in latitudinal patterns of species diversity
Few species might be able to tolerate harsh conditions found at higher latitudes. Also, climate is more stable in the tropics (over geological times) allowing accumulation of more species over time.
describe the factor of evolutionary rate in latitudinal patterns of species diversity
Higher temperatures would result in faster speciation rates through an influence on mutation rates and species generation time
-Colder temp-> everything slowed down metabolically
describe the factor of niche hypothesis in latitudinal patterns of species diversity
Species in the tropics are competing with many others and have higher parasite loads (no winters to kill them). This would prevent some species to dominate and lead to niche specialization (they dont become better adapted to the environment and outcompete other species because of their parasite load)
describe the factor of Rappaport’s rule in latitudinal patterns of species diversity
Rappaport’s rule= Latitudinal ranges of plants and
animals are generally smaller at lower than at high
latitudes.
->Can pack more things into a larger area (more space in the topics)
how does species diversity relate to latitude?
The decrease in diversity when moving from lower latitudes towards higher latitudes is referred to as Latitudinal Diversity Gradient. Generally it is observed that the diversity richness is more in the areas near the equator than at the poles.
->Overall, a combination of the different hypotheses is
probably responsible for this pattern
what is an endemic species?
A species found naturally in a single geographic area and
no other place is endemic to that location
what is the Species diversity Functional significance?
- Area of great debate and uncertainty
Link between species diversity and ecosystem
productivity:
->More species (each specialized on a specific resource)
will do a better job at exploiting all resources
available and hence increase productivity
Link between species diversity and ecosystem
stability:
->An ecosystem with high species diversity should be
able to cope with variable conditions better because
it has a wider range of tolerance (the sum of tolerance of all species in that system)
define community and ecosystem
Community: an assemblage/collection of populations of
different species that occupy a certain geographic area
Ecosystem: community + abiotic variables
what is Ecological/Community diversity largely driven by?
Largely driven by temperature and precipitation regimes
what is the functional significance of community diversity?
Functional significance is huge:
more types of communities–> more diversity
Sum of biotic and abiotic conditions is the ‘set in which
the actors (populations) evolve’
how do each of the levels of biodiversity relate to conservation?
genetic:
-Little attention (changing now)
Problems with small populations= Inbreeding, founder effects, declining populations, fragmentation
-Public perspective is that it does not really matter
(can we change this?)
species:
-‘Traditional’ unit for conservation efforts
-International Union for Conservation of Nature (IUCN) red
list (endangered, threatened, least concern)
-Can’t protect a species without preserving others it
depends on (Flagship species/biased and normally a charismatic large vertebrate and umbrella species/protecting these species indirectly protects the many other species that make up the ecological community of its habitat)
community:
- Probably the most important and the best approach
- Killing two (or more) birds with one stone
define Global extinctions
is at the species level. No longer found anywhere in the world. (ex. Tasmanian Tiger)
Globally extinct species surviving in captivity?
At the species level, no longer found in natural conditions anywhere in the world
what are Local extinctions?
- Locally extinct: at the population level. No longer
found where it used to be, but can still be found
elsewhere. Synonymous to extirpated
what are Ecological extinctions?
- Ecologically extinct: at both species or population
level. So rare that it no longer serves an important
ecological role
ex. sea otters on west coast - They like to eat sea urchins and therefore the kelp forests will grow/flourish as not as many urchins are eating the seaweed. The sea otters have a keystone role.
Pseudoextinctions?
Ancient species that gave rise to new species no longer
exist
Extinction by hybridization?
Not many documented examples, but thought to be very
possible. Occurs through complete mixing of a species,
subspecies, population, etc… with another.
ex. Capra ibex ibex (locally extinct)
What makes certain species more vulnerable to
extinctions? Five *general factors:
****
1- Narrow geographic range 2- One or a few populations 3- Small population size 4- Declining population size 5- Hunted or harvested by people
What makes certain species more vulnerable to
extinctions? Ten more *specific factors:
1- Large home range 2- Large body size 3- Not effective dispersers 4- Seasonal migrants 5- Little genetic variability 6- Specialized niche requirements 7- Form temporary aggregations 8- No prior contact with humans 9- Relatives went extinct
describe how large home range is a risk factor for extinction
Contradicts the narrow geographic range idea… It
relates to habitat degradation (fewer and fewer contiguous patches of habitat). Affects mostly mammals, especially predators.
ex. Male cougars have home range of ~ 1000 km2
->requires a lot of land mass
describe how large body size is a risk factor for extinction
Due to a combination of factors: including home range,
selective hunting, small population sizes, low reproductive rates, etc…
describe how not effective dispersers is a risk factor for extinction
•Unable to cope with changes in local conditions (natural disaster, etc.) so it would be nice if you could get out of there, if not then not good and could die
ex. butterflies that are good dispersers are less likely to be threatened
describe how being a seasonal migrant is a risk factor for extinction
they rely on 2 or more habitats… thus more likely to experience change
->You’re depending seasonally on habitat and food to travel large distances (takes a lot of energy)
•Ex. Delaware Bay- Horseshow crabs video, we have an impact during their seasonal migrations (also, They have to spawn on the beach for the Red Knot to survive).
describe how having little genetic diversity is a risk factor for extinction
•Cant deal with any environmental variability.
describe how having specialized niche requirements is a risk factor for extinction
•Ex. The orchid- need the bees to help with their pollination
-> limited window of survival
describe how species that form temporary aggregations is a risk factor for extinction, give examples
Close proximity of individuals increases vulnerability to
local catastrophes or to human exploitation
• Ex. The passenger pigeon (extinct north American bird that had massive flocks that turned the sky black, took 14 hours to pass. Were hunted on a massive scale-cheap food for slaves, etc.). Martha was the last one
• Ex. the buffalo (were slaughtered almost to extinction in 1800s where there was less than 1000, now there is 500,000)
describe how having no prior contact with humans is a risk factor for extinction
•Especially true for islands lacking predators. Flightlessness is not a good thing to be able to move out of an area
->But, of course sensitive species might already be extinct on long-occupied islands
describe how having relatives that went extinct is a risk factor for extinction
Taxonomic units often share a certain number of risk
factors therefore if relative went extinct, you’re likely at risk as well
Risk Evaluation:
what are some organizations involved in the assessment of species status?
- International: International Union for Conservation of
Nature (IUCN) - Continental: Natural Heritage Network and Nature
Conservancy, NatureServe conservation status - National: Committee on the Status of Endangered
Wildlife in Canada (COSEWIC)
Overview of pet cat problem
Estimated that cats are responsible for 100-350 million
bird kills per year
In the US it is 1-4 billion birds killed per year.
• 8.5 million pet cats
– Largest source of human related bird mortality in Canada
• 1.4-4.2 million feral cats
– Lack of information on feral cat predation
• Feral cats have been implicated in the extinction of at least 33 bird species
List the factors of the study you thought were potentially problematic
- Unreported mortalities (house cats and feral cats)
- Population estimates of feral cats may be underestimated
- The data they got wasn’t from Canada (was it representative?)
- High variability in the factors estimated
- Underestimates of pet cats that have access to the outdoors
- Inflated because there are other animals that kill birds (Did a bird hit a window, a cat found it and brought it home?)
- Seasonal effects unaccounted for
- All of Canada is not represented. Potential
geographic bias
If we still have cats
• What should we do? solutions?
- Limit time outside
- Leash (catio)
- Cat license—train owners
- PIT tags for cats—keep track of owner—fines
- More strict spay and neutering rules—no reproductive capacity without breeding licence
- Predator control
- Make cat indoor cat toys less expensive
- Bell on a cat
- Rainbow scrunchies
- Shock collar to reduce free range
- Increase rehabilitation efforts for feral cats
- Pet stores are only allowed to sell rehabilitated/feral cats
- Focus on protecting the birds (make bird friendly environment)
Should we have pets? what are the pros and cons?
Pros: • Comfort • Service animals • Teach responsibility • Labour—pets in a way – transportation • Drug dogs • Law enforcement • Protection • Chickens • Entertainment
Cons:
•Carry disease/parasites
• Exploitation of exotic or rare species
• Some are not domesticated
• Cost a lot of time and money
• Obligate carnivores create issues with climate change due to meat requirements (Increase carbon emissions)
• Dangerous animals— mortalities/injuries (pet snakes)
• Ethical treatment (some people don’t know how to care for their pet)
• Introduction of invasive species
• Good quality of life
what are the three goals of conservation biology ?
1)Document biological diversity-> - Origin, Ways to quantify, Patterns & Functional significance
2)Investigate human impacts on biological
systems (threats to biodiversity)
3)Develop approaches to minimize
anthropogenic impacts
Threats to biodiversity? 7
1- **Habitat destruction (or loss) 2- **Habitat degradation 3- Habitat fragmentation 4- Overexploitation 5- Species introduction 6- Spreading of diseases 7- Global warming
Habitat loss vs degradation
habitat loss definition: impacts so severe that all, or nearly all, species are adversely affected, or to cases where the
time span needed for recovery is extremely long
habitat degradation definition: impacts that affect many but not all species, and that may be temporary (although
many impacts are persistent at low-medium levels of
intensity)
*Loss of biomes and ecosystems often around water as people like to be near water
what are some human threats to marine ecosystems?
coastal development, shrimp farms, trawl fishing(scrapes the marine floor?), commercial fishing and ports create pollution and introduce non-native species
how do organisms die from habitat loss?
Individuals are either killed directly or forced to migrate to
remaining habitat, where artificially inflated densities will
eventually take care of them.
Ecological footprint?
the influence of a group of human individuals has on the environment, measured as land area needed to sustain their needs
->more developed areas tend to have a bigger footprint-• Canada has a high footprint
what are biodiversity hotspots?
•Biodiversity hotspots: where about 50% of worlds species contained in 7% of the land
Describe habitat loss of tropical rainforests ? converted to? problems?
Initial size (16 million km2)
Approximately half is remaining. 1 % is destroyed
annually
->Biodiversity hotspot
Land converted to:
- Pasture land
- Subsistence agriculture-when farmers grow food crops to meet the needs of themselves and their families
- Large-scale agriculture (monoculture= cultivation of a single crop in a given area)
Problems:
- Top soil is thin and nutrient-poor because of rapid circulation of nutrients in natural forests (doesn’t stay in soil for long)
- Rapid erosion and nutrient depletion
- Agricultural operations need to be moved after a short time
- Soil is nutrient poor and you burn it all up after agriculture and get the little nutrients that were there but it doesn’t come back fast
Describe habitat loss of tropical and temperate deciduous forests
- 97% of Madagascar’s tropical deciduous forests are gone
- Almost all of Europe’s old-growth forests are gone
Describe habitat loss of grasslands and savannahs. converted to? problems?
Between 1800 and 1950, > 95% of grasslands in USA
converted into farmland
Consequences inland:
- Regional and global changes in climate
- Water control and erosion
- Desertification
Describe habitat loss of freshwater ecosystems (wetlands). converted to? problems?
wetlands= swamps, marshes, bogs, vernal pools
- Can easily be drained and converted into cropland
- Many cities built on wetlands
- 50% of US wetlands gone
- 97% of vernal pools gone in some areas in California
- people dig ditches and allows water to come off wetland area-> create parking lot
- Peat moss removed by big tractors sucking them up and selling them as nice absorptive material
Describe habitat loss of freshwater ecosystems ( lakes and rivers). converted to? problems? The Aral Sea
• Soviet government diverted the Syr Darya and the Amu
Darya rivers for irrigation purposes. (the Aral Sea has been shrinking since the 1960s after the rivers that fed it were diverted by Soviet irrigation projects.)
• Salinity went from 10g/l to more than 100g/l.
• Water level has dropped over 23 meters.
• Was one of the four largest lakes in the world—68,000 km2
-The desiccation of the Aral Sea greatly increased the number of dust and salt storms in the area
-lead to local climate change: The result was shorter and hotter summers, longer and colder winters, and a decrease in precipitations
-The region’s once-prosperous fishing industry has been devastated, bringing unemployment and economic hardship
Describe habitat loss of freshwater ecosystems ( lakes and rivers). converted to? problems? The mighty Colorado River
On the Water-Starved Colorado River, Drought Is the New Normal (from dams, irrigation and now climate change)
- A few wet years in a long dry spell would be critical these days to keep the Colorado from completely drying up
- Western states began divvying up the Colorado’s water, building dams and diverting the flow hundreds of miles to irrigate 3.5 million acres of cropland
Describe habitat loss of Marine environments. converted to? problems? ->mangrove forests
-Form in low energy coastal tropical areas, where
sediments accumulate
- Extremely important nursery habitat for fish and
crustaceans (exploited species)
- 35% of the world’s gone
-Research has shown mangroves are able to absorb between 70-90% of the energy from a normal wave (the trees mitigate the impact of a tsunami)
-Mangrove forests stabilize the coastline, reducing erosion from storm surges, currents, waves, and tides. The intricate root system of mangroves also makes these forests attractive to fish and other organisms seeking food and shelter from predators.
EEZ?
**
exclusive economic zone (EEZ)= is a seazone prescribed by the United Nations Convention on the Law of the Sea over which a state has special rights over the exploration and use of marine resources, including energy production from water and wind.
Cut down and converted in rice cultures, shrimp aquaculture basins
Describe habitat loss of Marine environments. converted to? problems? -> salt marshes
- Temperate equivalent of mangroves
- Thick cover of salt resistant herbaceous plants
- Highly productive habitat
- In the US: 50% gone
Describe habitat loss of Marine environments. converted to? problems? -> coral reefs
33% of marine fish diversity in 0.2% of the ocean’s area.
Mix of pollution, sedimentation, nitrogen addition, fishing, warming
resulted in 20% loss
• Impacted heavily- bleaching, massive loss of reefs, harvesting of coal (people use dynamite to fish and to get coal- bottom pic)
• Important area- biodiversity hotspot
Describe habitat loss of Marine environments. converted to? problems? ->continental shelf
Unregulated dredging/trawling =Great reduction in habitat complexity, Reef-forming species and bedrock flattened
-> forests of sponges and coal are gone and replaced with rows of mud, (these were a critical habitat for fish development)
On average, a single location is dredged 7 times a year in
the main fishing areas… no recovery possible
what is the Species-area relationships in terms of islands/mainlands?
islands contain fewer species than the
mainland.
Also that number of species on an island
decreases as island area decreases.
define Richness
of species (S)
what are Diversity indices?
when you only look at number
of species in a community you typically ignore
the fact that some species are rare and others
are common. Some have great biomass and
others little. A way to get around this problem is
to use the following indices (there are others):
1. Simpson’s index
2. Equitability (Evenness) E
3. Shannon Weaver diversity index H
4. and Equitability J
describe the three complementary approaches to
island biogeography
- Concentrates on the suitability of islands as
habitats for various species ( habitat diversity). - Balance between the rate at which islands are
colonized by species new to an island and the
rate at which resident species go extinct on the
island. - Considers the balance between colonization
from the outside of the island and the evolution
within it.
Most obvious reason why larger areas should
contain more species is ??
Larger areas typically encompass more different habitat types
Lack (1969b, 1976) suggested that the number of
species reflects the “type” of island within which
he included its climate and habitat. He suggested
that large islands contain more species because
they contain more habitats.
what are the problems of Lack’s Island argument?
- Lack studied birds, he proposed that the
reason a species did not colonize an island
was not from a failure to disperse but from a
failure to find the right habitat. - In addition his argument does not
acknowledge the importance of evolution
within the island itself.
what is MacArthur and Wilson’s equilibrium theory?
• Number of species on an island is determined
by the balance between immigration and
extinction
– and that this balance is dynamic (ongoing), with
species going extinct and being replaced (through
immigration) by the same or different species.
describe the relationship of immigration and extinction rates on an island
•Immigration rate is high when no species are present
and reaches 0 when all species from the source pool
are present.
• Extinction rate is 0 when there are no species on the
island and will generally be low with few species.
–> However we would expect a priori that extinction rate will increase at a more than proportionate rate because with more species competitive exclusion is to be more likely and population size on average will be smaller making extinction more probable.
->The number of species where the two curves cross is in dynamic equilibrium.
with the immigration/extinction model we can make a number of predictions:
• The number of species on an island should eventually
become roughly constant through time.
• This should be a result of continual turnover of species,
with some becoming extinct and others immigrating.
• Large islands should support more species than small
islands.
• Species number should decline with increasing
remoteness of an island.
define Habitat fragmentation
Large contiguous area of habitat is reduced in area and
divided in several isolated patches
-Reduction in population is not proportional to the decline in total area of habitat
what are Population Viability Analyses (PVA)
typically simulation models, based on real data, that projects population trends in time
-uses population growth rate, population size and carrying capacity to find rate of population change
what’s the Minimum Viable Population (MVP)?
the smallest population that has a X probability of surviving over X years
-use extinction probabilities
what are the Problems with PVAs and MVPs?
0Require a tremendous amount of quality data to be
realistic
-Outcome is highly dependent on population model used,
and to parameters (e.g. carrying capacity)
-Assumes somewhat stable conditions in the future
->Lots of possible expansions and modifications… but very system-specific
