NR 300 Midterm 2
Terms in this set (55)
five major drivers of species loss and decline?
- Habitat loss is the main reason
- invasive species
- climate change.
What are the four broad ways is climate changing?
3. Extreme weather events
4. Sea level rise
What characteristics of a species make it especially vulnerable to climate change?
1. Low dispersal rates
2. Specialized habitat requirements
3. Limited physiological or behavioral plasticity
4. Low genetic variation
5. Strong dependencies on other species disrupted by climate change
7. Reliance on environmental triggers as a cue for life history events such as breeding or flowering
What could you do to make your region more resilient to climate change?
1. Minimize human stresses
2. Increase connectivity/corridors to allow movement
3. Expand protected area network
4. Assisted migration
What are the risks of assisted colonization?
1. Better to focus on reducing greenhouse gas emissions
2. Species could become invasive in new range
3. Create "unnatural" communities
4. Translocated individuals may not survive
What are the benefits of assisted colonization?
1. Existing protected areas are inadequate
2. Species may go extinct if we don't act
3. We are doing it anyway
4. Better to have an "engineered" world than a world with more species loss
What is targeted overexploitation?
Selectively hunting, fishing, logging or collecting particular species
What is Non-targeted overexploitation?
The taking of species accidentally or opportunistically.
Examples of target exploitation in tropical ecosystems:
1. Timber extraction
2. Hunting (bushmeat)
Examples of Non-target exploitation in tropical ecosystems:
1. Logging (tree-fall gaps)
2. Loss of large-fruited plants
Examples of target exploitation in temperate ecosystems:
Examples of Non-target exploitation in temperate ecosystems:
1. Ecosystem engineers (e.g. beavers)
2. Food web disruption
Examples of target exploitation in marine ecosystems:
75% of world's fish stocks fished out or overexploited.
Example: Atlantic Cod
Examples of Non-target exploitation in marine ecosystems:
27 million tons of by-catch annually!
e.g. 5:1 (by-catch: shrimp)
why is bush meat hunting only recently having substantial negative impacts on biodiversity?
Improved hunting tactics
Why is marine bycatch especially problematic for seabirds and turtles?
They are not as fecund
Why is overexploitation generally a larger problem for species in marine environments relative to terrestrial systems?
Tragedy of the commons
Why do populations generally exhibit logistic growth?
Limited resources and space for populations (carrying capacity)
label the x and y-axis, K and K/2 on a graph of logistic population growth
K: carrying capacity
K/2: Maximum sustainable yield
What is Maximum sustainable yield?
the largest number of animals that can be harvested from a population and maintain the population at a stable level
Where is Maximum sustainable yield on a graph?
Middle of upslope
Why does Bill McKibben argue no place left on earth is pristine nature?
Because lead, mercury and other toxic heavy metals
are being found in remote areas of the arctic and Antarctic there is no environment not affected by humans
What are the problems with using MSY as a tool for sustaining wild populations?
Humans don't know where exactly this number lies on the population curve
How do endocrine disruptors affect alligators and other species?
Chemicals mimic or block hormones causing tiny reproductive organs and high female hormone levels, low reproduction and declining population
What is biomagnification?
At each higher level of the food chain chemical pollution within animals is magnified
Who wrote Silent Springs about DDT
Species introduced to Lake Victoria
Difference between density dependent and independent factors
Density-independent factors: influence birth and death rates independent of population density
Density-dependent factors: have a negative or positive impact on birth/death rates as population density increases
What is the positive density dependence factor called?
What is meant by the term "extinction vortex"?
the process that declining populations undergo when a mutual reinforcement occurs among biotic and abiotic processes that drives population size downward to extinction
Distinguish between proximate and ultimate causes of extinction
A proximate cause is an event which is closest to, or immediately responsible for causing, some observed result
The ultimate cause which is usually thought of as the "real" reason something occurred
What were the proximate causes of extiction for the heath hen, passenger pigeon, Carolina parakeet and ivory-billed woodpecker?
1. Lost Hollows (habitat)
2. Invasive species
What were the ultimate causes of extiction for the heath hen, passenger pigeon, Carolina parakeet and ivory-billed woodpecker?
these birds probably required minimum flock size
to breed and find good habitat. As the
species aged, genetic diversity was lost
- could have led to some sterility.
What is meant by an ecologically functional population?
populations that are large enough to fulfill their ecological roles, thus preserving the essential species interactions that are the backbone of ecological
Why should conservation biologists be concerned about genetic diversity?
Genetic variation is the raw material for future adaptation and is the basis for a species responsiveness to environmental change
Forces that impact genetic variation
- Natural Selection
- Genetic Drift
- Gene flow or immigration
Why are individuals not all genetically identical?
- Recombination through sex
What is gene flow?
movement of genes from one population to another
What is the founder effect?
the reduced genetic diversity that results when a population is descended from a small number of colonizing ancestors.
What is outbreeding depression?
declines in fitness of hybrids due to "genetic swamping" of locally adaptive genes through gene flow or directed mating
How is effective population size (Ne) different from N? What does Ne account for?
Functional size of a population based on the actual
numbers of breeding individuals. Accounts for non-breeding members
People have trained dogs to find animal feces or plant material. How does this benefit species conservation?
Feces are a treasure trove of biological information (DNA,hormones, parasites, toxins) and dogs can find feces over a large area faster than humans
How were imposter fish identified?
Their DNA was tested
What is population viability analysis?
examines the demographic effect of different threats or management practices on a population by projecting into the future to predict extinction risk. A PVA is a form of "quantitative risk analysis"
What is an Ecological Trap?
habitat that resembles a source but is really a sink
What are the four key characteristics of a metapopulation?
- semiindependent local populations
- interplay between local and regional populations
- While few species may live as metapopulations, many species depend on metapopulation processes.
- Predator-prey and competitive interactions
What are the conservation implications of roads and other barriers between subpopulations within a metapopulation?
roads and other dispersal barriers decrease connectivity of populations, leading to fragmentation that divides a homogeneous population
into several smaller populations
Why are small subpopulations potentially as important as large subpopulations for maintaining a metapopulation?
A mixture of smaller and larger populations can
hedge against uncertainty in the scale of future
impacts, and it has potential genetic benefits
What is the rescue effect?
When species from a large population emigrate to a smaller one and rescue that population from extinction
What is the difference between conservation genetics and genomics?
Genetics is the study of inheritance of characteristics and traits. Genomics the study of all or many genes in the genome and their interactions with each other and the environment
What is used to amplify particular regions ("markers") in DNA so that base pairs or sequences can be compared.
Polymerase Chain Reaction (PCR)
What are the advantages of using conservation genetics rather than traditional lek counts to assess population size/dynamics in the Sage Grouse?
lek counts underestimate population sizes and Non-invasively sampled DNA can be used as a unique
"mark" in mark-recapture work
One of the key conclusions of Dr. Oyler-McCances study of Greater Sage Grouse subpopulations is that "populations followed isolation by distance". What does that mean?
Movements are typically among neighboring
populations but not long distance movements across
What is landscape genetics?
interdisciplinary field that integrates approaches from population genetics and landscape ecology.
Dr. Oyler-McCances work led to the Gunnison Sage Grouse being defined as a unique species (differentiated from the Greater Sage Grouse). What was the evidence that led to this decision?
Population genetic analysis of all Sagegrouse