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Qualitative vs. Quantitative Sampling
What is the difference between: Quantitative and Qualitative
Sampling??
• Qualitative Sampling:Observational evaluation of some
attribute.
• Quantitative Sampling:The measure or count of some
attribute.
Qualitative Sampling• Observational, not direct measurement.• Observer makes evaluation on condition
or quantity.• Often much quicker than quantitative
sampling.• Can be timely for making quick
management decisions.• May be more subject to observer bias than
quantitative sampling.• May be difficult to verify.
Different Types of Qualitative Sampling
• Presence or absence of species or trait
• Site-condition evaluation• Rough estimates of population size or
attribute• Photo interpretation
Presence or Absence
Plant survival after fire
Rare plants
Evaluate Spread of Disease
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Evaluation of Site Condition
•Poor grazing quality
•High fire potential
Assess Population
Size
Qualitative
Quantitative
Qualitative Data: Use of Photos
• Photo Documentation• Photo Plots• Photo Points• Remote Sensing – aircraft, satellite
All can trigger or guide management actions
Photo Documentation of Treatment Effects
Photo Documentation
of Invasive Weed
Encroachment
Edge encroachment
Dispersed encroachment
Photo Plot
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Photo PointsMarch, 2002
April, 2002
May, 2002
Aug, 2002
Sep, 2002
Remote Sensing from Aircraft
• Normal photo image• Spectral Images – e.g., infra-red band• Digital Pixel Size: Often 10 cm to 30 m
Remote Sensing
from Aircraft
(infra-red)
Spring
Ant colonies (relative density)
Community boundaries
Remote Sensing
from Aircraft
(infra-red)
Juniper stand (density, tree dimameter)
Roads/trails
Satellite Remote Imaging
• Normal Image Photo• Multi-spectral bands• Pixel Resolution: 0.25
km - 10 km
Remote Sensing from Satellite
Fires in southeast USA
Volcanic Ash, Kodiak Is.
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Remote Sensing from Satellite
Dust storm in Afghanistan
First snow, Lake Baikal
Satellite Processed Images
Gross Primary Production (gross photosynthesis)
Determine at least one qualitative and one quantitative sampling method for each objective
1. Determine whether a specific toxic substance is leaking from an old tank into the Logan River.
2. Determine age structure of a pronghorn herd in central Wyoming.
3. Determine whether canvasback ducks are migrating through Cache Valley, Utah.
4. Determine whether ATV users have been driving off trail in Swan Flat.
5. Determine whether West Nile virus has reached Utah.6. Determine forage availability for sheep on a winter
allotment.7. Determine whether common dandelion has invaded
your lawn.8. Determine whether volcanic ash from Kodiak Island
volcano is reaching the Anchorage, Alaska airport.