Post on 21-Jan-2016
transcript
NATURE UNBOUNDLESSON 3 – POPULATION CHECKS AND BALANCES
Conservation
Mr. Dieckhoff
THE MISSOURI OTTER
Working with the people at your table, answer the following question: What information do you know about Otters?
Missouri Department of Conservation Video https://www.youtube.com/watch?v=OzG98Fbx7G4 https://www.youtube.com/watch?v=Qve3jLhMYRI
POPULATIONS Boundaries set by
What is the boundary of the Asian Carp?
Population Size - Population Density – Dispersion –
Clumped Uniform Random
MARK-RECAPTURE METHOD
1. Catching a sample of the population and marking the captured individuals with paint, a leg band, an ear tag, etc..
2. After marking, release and allowed to mix back into the population
3. After a period of time, a second sample of individuals is collected from the same place
Lincoln-Petersen Estimate
SAMPLING POPULATIONS
Census – Sample –
Quadrats
Transects
SAMPLING POPULATION EXAMPLES
Black Bears https://www.youtube.com/watch?v=bYoFrPSybiE https://www.youtube.com/watch?v=tJNlstEYHmU
Electrofishing https://www.youtube.com/watch?v=unAdz09rjvg
Ducks https://www.youtube.com/watch?v=I88MJWpcoH4
Otters https://www.youtube.com/watch?v=_VdQnsG8KFQ
POPULATION SIZE CAN GO UP OR DOWN Increased by – Decreased by –
With abundant resources, populations grow quickly Exponential growth –
population increases in proportion to its size (J-shaped curve)
Per Capita Rate of Growth Compare birth and death
rates over time to see if population is increasing or decreasing
LIMITING FACTORS Factors that slow a
population’s growth or prevent it from existing in an area Abiotic – Biotic –
Density-Independent Factors Limiting factors that affect
population regardless of its density
Examples –
Density-Dependent Factors Limiting factors that affect a
population related to its density
Examples –
https://www.youtube.com/watch?v=_e1KA8CpPnA
https://www.youtube.com/watch?v=IrTYdG1s1OA
THE HUNTING DEBATE
Compensatory Mortality Consider a mallard population
in which winter food is a limiting factor. With a large population, there isn’t enough food to go around, and 10,000 ducks die each year of starvation. If hunters kill a percentage of the population, there is more food available to the surviving mallards, and fewer ducks starve. In this example, the number of mallards that die will be the same regardless of whether hunting or starvation is responsible. Thus, if hunters kill 6,000 ducks, 4,000 will die from starvation, and if hunters kill 8,000 ducks, 2,000 will die from starvation.
Additive Mortality If hunters kill 5,000
ducks, it would add to the 10,000 that normally die of starvation. Thus, the population would decrease by 15,000 ducks.
CARRYING CAPACITY
Definition:
CULTURAL CARRYING CAPACITY Number of animals
people will tolerate Issues of urban deer:
https://www.youtube.com/watch?v=AbQQ9cItlOo
Deer birth rates are high Many does produce twins 10-15% produce triplets Higher in northern Missouri
Death rates are falling Fewer predators Hunters take 40-70% of
antlered bucks Hunters take 25% of does What has more affect on
deer populations? harvesting bucks or
does
CONCLUSION
1. Populations – Size, Density, Dispersion2. Mark-Recapture Method3. Sampling Populations4. Population Size Changes5. Limiting Factors6. Hunting – Compensatory vs. Additive7. Carrying Capacity
Cultural Carrying Capacity