Wildlife Management- Habitat Sampling Guidance

Thoughts on sampling for habitat evaluation:

• Sample to understand the nature of the stand

• Enough sample sites to capture the variation of the stand

• The more variable the stand, the more sites you needed

• The bigger your sampling plots/sites, the less you need

• Bigger stands tend to be more variable

• Random locations are standard

• Scale of what you’re measuring influences size of plots

  • Sampling trees requires bigger plots/sites than shrubs which require bigger plots/sites than understory

• What you are sampling determines how you sample it

  • Line or point intercept

  • Plots (fixed or variable radius)

    • Basal area (requires size of trees (dbh) and number of trees)

  • Transects

  • Density estimates require an area (some value per area… 16 trees per hectare, 54 seedlings per sq. meter, etc.)

Common methods for measuring vegetation characteristics: Density, species occurrence, dominance, frequency

• Quadrats, transects (set length and set width)

  • Size determined by what you are sampling:

    • Quadrats- Trees- 25m x 25m

    • Shrub- 10m x 10m

    • Herbaceous/Ground Layer- 1m x 1m

    • Transects- 5-10m wide for trees

Common methods for measuring vegetation characteristics: Canopy closure/coverage (vertical)

• Line or point intercept, densiometer, quadrats for understory vegetation

  • Visual/ocular estimates

  • Ex. Line Intercept

    • 1) Lay out tape measure

    • 2) Walk the line and mark the start and end on the measure where plant canopy cover crosses above/intersects the line

    • 3) Calculate percentage canopy cover based on how much of the total length of tape was under canopy

Common methods for measuring vegetation characteristics: Visual obstruction/cover (horizontal)

• Visual obstruction board, robel pole, etc.

  • Ex. Robel Pole- record how much is above veg

  • Ex. Visual Obstruction Board- record how much is visible behind/through veg

Common methods for measuring vegetation characteristics: Tree Height, DBH, Basal Area

• Tree Height- clinometer

• Tree DBH- dbh tape (used in quadrat, along transect, etc.)

• Basal Area- bitterlich prism (variable radius plots at sample points) or record dbhs and do the math at sample points

  • Requires dbh and number of trees