Population Ecology Pt.1

What is a population?

A population is a group of organisms in the same species who are occupying the same space at the same time as well.

What are the levels starting with indivuals?

Individuals, population, community, ecosystem, biome, biosphere

What are the structural attributes of a population?

Sex Ratio, Age ratio, Genetic Structure, seasonal structure, social structure, and dispersion.

What are the functional attributes of a population?

Turnover rates, rate of growth, size and density changes, homeostatic regulatory mechanisms, and adaptational mechanisms.

What is the difference between structural and functional attributes of a population?

Structural is at one point in time and functional is over time.

What is evolution and who evolves?

A population evolves and this is by the change of allele frequencies over time in a population.

Density?

Number of individuals per unit area

Birth Rate?

The number of births per individual per unit time (usually year)

Death Rate?

The number of individuals that have time per unit time (usually year)

Age Structure?

The distribution of numbers of individuals of various ages

Sex Ratios?

Ratio of males and females pertaining to each other

Fecundity?

This is the hypothetical number of offspring that a female can produce. Number of eggs produced per female

Fertility?

The percentage of eggs that are actually fertile

Production?

The actual number of offspring produced or sometimes the number of individuals reaching breeding age.

Recruitment?

The number of individuals reaching breeding age plus immigration(+)

Why is it hard to find the density of wild populations?

It is hard because populations are always moving and changing and it is hard to define boundaries.

There a different types of density, what is Crude?

The number of individuals/ total space.

What is specific or ecological density?

Number of individuals per habitat space

What is relative abundance or standing crop density?

This is the number of individuals at any given time. Usually used with plants

What is constantly changing in populations?

Natality(+), mortality (-), immigration(+), emigration(-)

What is the relationship between body mass and mean abundance when it comes to animals?

It is a negative relationship. The smaller the body size the higher the mean abundance is. This is because when the animals are smaller, this means they can multiple to bigger numbers and the habitat can still carry them. When it comes to larger animals they need more food, more space, so because of this they are limited to smaller numbers of mean abundance.

What are the general rules of density?

Density should be related to habitat (best one), seasonal differences (measure in the same seasons), habitat differences (when comparing biomass)

What are the two types of changing density?

Natural and human controlled

What is primary stocking?

This is when a species is introduced to a new ecological setting (exotic, non-indigenous).

What is an example of primary stocking?

The introduction of feral hogs into texas is an example of primary stocking.

What is secondary stocking?

The reintroduction of native species into a former range

What is an example of secondary stocking?

The reintroduction of whooping cranes in the Eastern migratory population.

What is primary transplant?

The release of individuals within existing range, so putting a set of individuals from one population to a different range but to establish a new population.

What is an example of primary transplant?

Merriam’s Wild Turkey Transplants into the Black Hills (South Dakota, early 1900s). Wild turkeys were caught from new mexico and colordo and transplanted into the black hills to establish a new population.

What is released game?

This is when game is released for hunting season

What is an example of released game?

Rainbow trout in guadalupe river are released every year for hunters to catch and since they know that they will be hunted and fished for it is not that big of a deal to release them.

What is the difference between primary transplant and released game?

Released game occurs because of captive breeding. Primary transplant is taking a wild population and putting them into existing range.

When estimating a populations density, what is the best way to do it?

The best estimate is one that takes into consideration the time, resources, and personnel available to do these things.

What is a census?

A complete count of all individuals in total area

What is a sample census?

Complete count in the areas subsample

What is a census estimate?

This is the estimate of population in a given area based on sampling (NOT all individuals counted for).

What are ariel counts?

This when counts are observed in the air, this has been used for 100s of years and is the most successful in open areas.

Which animals can you count when using Fixed-wing aircrafts?

You can count waterfowl populations

What animals can you count when using helicopter counts?

Deer and elk because it is a good tool to estimate sex ration and age structure.

What is FLIR?

Forward looking infrared radiometers and thermal imaging cameras.

What are some examples of sampling counts?

Point transects, line or strip transects, and mark and recapture.

What are indirect counts?

This is when you do not actually see the organism but traces of the organism. So scats, pellet counts, track counts, auditory indices.

What is wrong with indirect counts?

They are usually not good indicators and estimates of a population size or density. The results or not meaningful unless there has been multiple years of data available for a trend to occur in the data.

What is a clumped distribution and what are some benefits of having this kind of distribution?

It is when populations are clumped together and this provides many eyes to search for food sources and also any predators. Another benefit is that it confuses the predator and there is also hunting cooperation (wolf packs).

What is regular/uniform distribution?

It is constant distance maintained between individuals. This usually occurs in territorial animals who are defending their resources or breeding territories. It also helps ensure adequate resources for each individual

Why do penguins have a uniform distribution?

Because they are protecting the eggs and they do not move as much so that the distance they are between neighbors can be close enough if they need to fight but also not disturb the egg.

What is random distribution?

This is rare but when exhibited by individuals that do not form social groups.

What is the dynamic in a tropical forest?

They each fight for light. Lets say that a tree falls and dies. This opens up a spot of sunlight in the forest and now pioneer species can enter and succession starts. But you do not know what species ends up winning. So whoever by chance gets their first may establish themselves in that spot that was once empty and full of light for others to fight over it.

What are some factors that affect distribution of populations?

Interactions b/w individuals within a population so mutual attraction, avoidance, neutral response. The physical environment, maybe there is patches and so they are cut off, combination of interactions among individuals & the environment setting.