Animal Population Sampling Methods
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Questions and Answers

Which of the following methods can be used for trapping flying insects?

  • Sweep nets (correct)
  • Cannon nets
  • Pitfall traps
  • Malaise trap (correct)

    • What is the purpose of marking animals?

  • To increase their weight
  • To change their habitat
  • To breed with other species
  • To distinguish certain members of a population (correct)

    • What type of trap is often used for nocturnal insects?

    Ultraviolet light traps

    Name one method used for aging animals.

    <p>Determining sex</p> Signup and view all the answers

    Tags such as _______ are used for marking fish.

    <p>strap tags</p> Signup and view all the answers

    Marking animals for research purposes always causes them stress.

    <p>True</p> Signup and view all the answers

    What was the proportion of males in the rabbit population during the first survey?

    <p>0.6</p> Signup and view all the answers

    N1 refers to the estimated population before any removal of individuals occurred.

    <p>True</p> Signup and view all the answers

    What is the formula used to estimate N1 in the study?

    <p>N1 = (Tx - V2 × T) / (V2 - V1)</p> Signup and view all the answers

    Match the following parameters with their meaning:

    <p>Tx = Total number of individuals removed V1 = Initial proportion of a population V2 = Proportion of a population after removal N1 = Estimated initial population size</p> Signup and view all the answers

    Which of the following is NOT a method of non-area based sampling?

    <p>Standard Strip Sampling</p> Signup and view all the answers

    The selective removal technique involves sampling across a single time period.

    <p>False</p> Signup and view all the answers

    What does the variable 'D' represent in the population estimation formula P = D x A?

    <p>Density of animals per unit area</p> Signup and view all the answers

    In the equation for standard strip sampling, the density is calculated using D = y / (L * W), where y represents the number of animals in a sample plot, L is the length of the strip, and W is the ______.

    <p>width</p> Signup and view all the answers

    Match the following sampling methods with their characteristics:

    <p>Selective Removal = A method allowing for the removal of specific individuals from a population Mark-recapture = A technique that estimates populations over multiple time periods Change in Ratio = Analyzes population shifts by comparing ratios over time Standard Strip Sampling = Uses narrow, long plots to estimate animal density</p> Signup and view all the answers

    Which of the following factors could potentially affect the accuracy of population estimates?

    <p>All of the above</p> Signup and view all the answers

    Gender-based sampling is commonly used in area based methods.

    <p>True</p> Signup and view all the answers

    What is the purpose of using plotless sampling in biodiversity management?

    <p>To estimate population density without predefined sampling areas</p> Signup and view all the answers

    Which assumption is NOT required for the selective removal method to be effective?

    <p>Trapping occurs in all weather conditions</p> Signup and view all the answers

    The selective removal method requires that the animals are trap-shy or trap-prone.

    <p>False</p> Signup and view all the answers

    What formula is used to estimate the population at the first survey time (N1)?

    <p>N1 = (Tx - V2 × T) / (V2 - V1)</p> Signup and view all the answers

    In the formula for estimating population, T represents the total number of animals of variable ______ removed or added between surveys.

    <p>y</p> Signup and view all the answers

    What does the standard error (SE) help to calculate in population estimates?

    <p>The upper and lower population estimates</p> Signup and view all the answers

    Match the following variables with their corresponding definitions:

    <p>N1 = Population estimate at first survey time V1 = Ratio of variable during first survey V2 = Ratio of same variable during second survey Tx = Number of animals added or removed between surveys</p> Signup and view all the answers

    The selective removal method can take into account changes in sex ratios only.

    <p>False</p> Signup and view all the answers

    What is the primary challenge in meeting the assumptions for selective removal?

    <p>Ensuring constant capture probability across different conditions.</p> Signup and view all the answers

    Study Notes

    Recap

    • Last week's lecture focused on plant population sampling methods
    • The quadrat, line intercept, belt transect and point-frequency intercept methods were discussed

    Animal Population Sampling Methods

    • Animal populations are sampled through trapping and collecting, marking, aging, sex determination, home range and territory determination, and estimating numbers.

    Trapping and Collecting

    • Several methods are used for trapping and collecting insects, aquatic organisms, soil organisms, small animals in vegetation, and birds and mammals.
    • Diurnal insects: Aerial nets, heavy duty sweep nets, and ultraviolet light traps are used.
    • Nocturnal insects: Mercury-vapor light traps, Malaise traps and quadrats or transects.
    • Aquatic Organisms: Dip nets, bottom nets, wire-basket scraper nets, plankton towing nets, trawl nets, and seine nets.
    • Soil Organisms: Varying funnel methods like Berlese or Tullgren funnels.
    • Small Animals in Vegetation: Sweep nets with frames, beating vegetation with sticks and canvas collecting trays, and drag nets.
    • Birds and Mammals: Cannon nets, mist nets, live traps (wood or wire), snap traps, Sherman traps, and traps with sticky surfaces, pitfall traps.

    Marking Animals

    • Marking animals allows researchers to track individuals over time
    • This information is used to estimate population sizes, track movements, and study behavior

    Marking Methods

    • Arthropods and Snails: Quick-drying cellulose paint
    • Fish: Strap tags, stream or pennant tags, plastic tags, acoustic tags, and clipping fins.
    • Frogs, Toads, Salamanders: Toe clipping.
    • Birds: Serially numbered aluminum bands, cellulose or aluminum colored bands, toe clipping, fur clipping, ear notching, tattooing, and dying plumage.
    • Small Mammals: Toe clipping, fur clipping, tattooing.
    • Larger Animals: Fur clipping, tattooing, dyes, GPS collars, strap tags, plastic discs attached to ears, and radio or GPS collars.
    • Note: Some methods are invasive, unethical, and have largely been phased out.

    Sampling

    • Most commonly used census technique
    • Two basic approaches: Area-based and non-area-based

    Area-based Sampling

    • Usually involves sampling during a single time period
    • Involves plots and plotless sampling
    • Basic equation: P = D x A
      • P = Population number
      • D = Density (number of animals per unit area)
      • A = Surface area (i.e.total area occupied by animals)

    Plot Sampling

    • Density calculated using D = y/a
      • D = number of animals per unit area
      • y = number of animals in a sample plot
      • a = area of the sampling plot
    • Follows the sampling methods of Quadrats and Standard Strip Sampling

    Standard Strip Sampling

    • Narrow, long plots with a fixed width
    • Equation used to calculate density: D = y/LW
      • D = number of animals per unit area
      • y = number of animals in a sample plot
      • L = length of strip
      • W = width of strip
    • y in the equation is the mean calculated from each transect or plot

    Non-Area-based Sampling

    • Usually involves sampling at more than one time period
    • Involves Change in ratio and Regression sampling methods
    • Plotless sampling

    Non-Area-based: Selective Removal

    • Involves removing individuals from the population — often influencing ratios of age, sex, or types of animals
    • Considers changes in ratios over two sampling periods
    • Assumptions:
      • Population is stationary
      • Probability of capture is equal for each animal
      • Probability of capture remains constant between sampling periods
    • Challenging to meet these assumptions

    Non-Area-based: Selective Removal Equation

    • Used to estimate the population at the time of the first survey (N1)
    • N1 = (Tx - V2 x T) / (V2 - V1)
      • N1 = Population estimate at the first survey time
      • V1 = Ratio of one variable during the first survey
      • V2 = Ratio of the same variable at the second survey
      • Tx = Number of animals of variable x that were added or removed between surveys
      • T = Tx + Ty, where Ty = number of animals of variable y (second gender or age etc.) that were added or removed between surveys

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    Related Documents

    Sampling Methods Part 3 PDF
    Sampling Methods Part IV: Census Techniques PDF

    Description

    This quiz focuses on various techniques used for sampling animal populations, detailing methods such as trapping, marking, and estimating numbers. It also covers specific tactics for different organisms, including insects and aquatic life. Test your understanding of these essential ecological methods!

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