Population Ecology Presented By: Dean Thomas. What is population ecology?

Population EcologyPopulation Ecology

Presented By: Dean ThomasPresented By: Dean Thomas

What is population ecology?What is population ecology?

A population is an assemblage of A population is an assemblage of individuals of the SAME species inhabiting individuals of the SAME species inhabiting a given area.a given area.

Ecology is a field of biology that focuses Ecology is a field of biology that focuses on the interactions between organisms on the interactions between organisms and their environmentand their environment

So population ecology is the dynamics of a So population ecology is the dynamics of a species population and how they interact species population and how they interact with their environment with their environment

What kinds of things do What kinds of things do population ecologists look at?population ecologists look at?

Population StructurePopulation Structure Population GrowthPopulation Growth

Population StructurePopulation Structure

Interested in how many individuals Interested in how many individuals make up the population. make up the population.

How are the individuals distributed How are the individuals distributed throughout the environment?throughout the environment?

Age StructureAge Structure

Types of DistributionTypes of Distribution

ClumpedClumped UniformUniform RandomRandom

http://www.biology.iupui.edu/biocourses/n100/images/39dist.gif

Distribution?Distribution?

http://io.uwinnipeg.ca/~simmons/16cm05/1116/52-02a-Clumped.jpg

King Penguins on Salisbury Plain – Over 100,000 Penguins!

http://www.vanda.eclipse.co.uk/travel/Antarctica/images/Chap_3/Part_3/SP_King_Penguins.jpg

http://io.uwinnipeg.ca/~simmons/16cm05/1116/52-02cx-RandomFerns.jpg

What type of distribution What type of distribution pattern do humans show? pattern do humans show?

Why?Why?

Population GrowthPopulation Growth

Growth Rate = the percent change in Growth Rate = the percent change in a population over one yeara population over one year

Growth rate is affected byGrowth rate is affected by ?? ?? ?? ??

Population GrowthPopulation Growth

Growth Rate = the percent change in Growth Rate = the percent change in a population over one yeara population over one year

Growth rate is affected byGrowth rate is affected by Natality (births)Natality (births) Mortality (deaths)Mortality (deaths) Immigration Immigration Emigration Emigration

Growth rate = birth rate – death Growth rate = birth rate – death raterate

Let’s try an exampleLet’s try an example A population of 100 rabbits gives birth to A population of 100 rabbits gives birth to

30 rabbits in one year.30 rabbits in one year. 30 births30 births 100 adults100 adults= .30 * 100% = 30% birth rate= .30 * 100% = 30% birth rate If 10 individuals of the 100 rabbits died, If 10 individuals of the 100 rabbits died,

what is the death rate?what is the death rate? What is the growth rate of the rabbit What is the growth rate of the rabbit

population?population?

What’s going to happen if this What’s going to happen if this continues?continues?

http://www.beltramiswcd.org/Aquatic%20Biology/Human%20Population%20Growth.jpg

If both of these species If both of these species became endangered, which became endangered, which

has a better chance of has a better chance of rebounding?rebounding?

Can a population grow Can a population grow forever?forever?

Animals have the capacity to grow Animals have the capacity to grow exponentially, but they are limited by exponentially, but they are limited by resources. resources.

What are the four main resources What are the four main resources that limit growth?that limit growth?

Can a population grow Can a population grow forever?forever?

Animals have the capacity to grow Animals have the capacity to grow exponentially, but they are limited by exponentially, but they are limited by resources. resources.

What are the four main resources that What are the four main resources that limit growth?limit growth? FoodFood WaterWater ShelterShelter SpaceSpace

Carrying CapacityCarrying Capacity The maximum The maximum

population that can population that can be supported by an be supported by an environmentenvironment

http://www.bio.miami.edu/dana/pix/logisticpopns.gif

http://www.geo.arizona.edu/Antevs/nats104/00lect21grolog.gif

Question:

What would happen if a population grew beyond their carrying capacity?

Carrying CapacityCarrying Capacity

Density-dependent factorsDensity-dependent factors

Density-dependent factorsDensity-dependent factors Population-limiting factors that increase Population-limiting factors that increase

as population increases in sizeas population increases in size Food suppliesFood supplies Risk of disease in crowded areasRisk of disease in crowded areas Increase in toxin concentration caused by Increase in toxin concentration caused by

increased waste levelsincreased waste levels Causes declines in birth or death ratesCauses declines in birth or death rates

Density-independent factorsDensity-independent factors Influences on population rates that are Influences on population rates that are

not affected by densitynot affected by density Severe droughtSevere drought Cold winterCold winter

Effects could be worse depending on the Effects could be worse depending on the size of population size of population

Age PyramidsAge Pyramids

Which of the two pyramids show a more rapid growing population? What if (a) was inverted?

Let’s look at population Let’s look at population ecology at work!ecology at work!

http://faculty.fullerton.edu/pstapp/IMG_3245.jpg

Abby Benson - Abby is studying the population ecology and sex-biased dispersal of thirteen-lined ground squirrels in and out of prairie dog colonies in northern Colorado. Her research is also part of the broader NSF-funded plague project underway in northern Colorado.

How do we estimate How do we estimate populations when we don’t populations when we don’t

have census data?have census data? It’s hard to count every individual It’s hard to count every individual

and can be very time consuming!and can be very time consuming! If the critters are mobile, they are If the critters are mobile, they are

probably sneaky and don’t want to probably sneaky and don’t want to be found. Makes your job a little be found. Makes your job a little harder.harder.

Examples of population survey Examples of population survey techniquestechniques

Plot sampling Plot sampling (Quadrat sampling)(Quadrat sampling) Estimate densityEstimate density Estimate percent Estimate percent

covercover What types of What types of

organisms is this organisms is this method good for?method good for?

What would it not What would it not work for?work for?

http://lh6.ggpht.com/_vgCJNdZcGw8/SGfKBHguBdI/AAAAAAAAAOg/yQIYwuH6g8c/SpellmanEcolab_Stephanie%26Me_plots.jpg

Mark-Recapture SamplingMark-Recapture Sampling CaptureCapture Mark all that you capturedMark all that you captured ReleaseRelease RecaptureRecapture Estimate population by the ratio of Estimate population by the ratio of

marked to unmarked marked to unmarked

Mark-Recapture SamplingMark-Recapture Sampling Equation: N/M = n/REquation: N/M = n/R

N = Estimated PopulationN = Estimated Population M = Marked individualsM = Marked individuals n = number of individuals in the second n = number of individuals in the second

samplesample R = Recaptured individualsR = Recaptured individuals So, N = Mn/RSo, N = Mn/R

Mark-Recapture SamplingMark-Recapture Sampling An exampleAn example

Mark-Recapture Sampling in Mark-Recapture Sampling in Action!Action!

Still Creek Fish Trap, Mt. Hood, Still Creek Fish Trap, Mt. Hood, OROR

Can you find the marked fish?

Back to the office to analyze the data!

Link to recent Hudson River Link to recent Hudson River plane crashplane crash

http://www.cnn.com/2009/US/01/15/hudson.plane.videos/index.html

http://img.photobucket.com/albums/v442/iftk/10/planer_vs_plane_001.jpg

http://www.dontdumponwilliston.org/images/bird-v-plane.jpg

http://img.photobucket.com/albums/v442/iftk/10/planer_vs_plane_002.jpg

Where does population ecology Where does population ecology come into play with the come into play with the dangers of bird strikes?dangers of bird strikes?

Well, lets be wildlife biologists Well, lets be wildlife biologists and take a look!and take a look!

Population Ecology Presented By: Dean Thomas. What is population ecology?

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