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Design and Analysis specifics and examples for Lakes
Monitoring Objectives and QuestionsTarget Population
- Definition
- Several aspects often need consideration to establish the target population
- Lake size (e.g., greater than 1 ha)
- Water depth (e.g., at least 1 m depth)
- Amount (%) open water (e.g., less than 50% covered by vegetation)
- Natural or including man-made reservoirs
- Wholly within the study area (e.g., lakes partly outside State not included)
- As a discrete population
- Questions focus on number of lakes that have a particular attribute
- Each indicator has single value for a lake
- Summary information provides number or proportion of lakes with particular indicator value
- As a continuous population
- Questions focus on percent of lake area
- Each indicator has single value at sample point within lake
- Summary information provides acres or proportion of the area of lakes with particular indicator value
- Florida - Example
- Lakes have been subdivided into two groups:
- small lakes, which are from one to 10 hectares in size,
- large lakes, which are over 10 hectares in area.
- This differentiation on the basis of area is intended to accommodate differing sampling strategies and methods.
Subpopulations (Often these aspects lead to 2 or more)
- Natural and Man-made
- Lake Size (e.g., 1-50 ha, 50-200 ha, 200+ ha)
- Geographic areas (e.g., States, ecoregions, proximity to urban centers, elevation, etc)
Results
National Fish Tissue Contaminant Lake Survey
New Hampshire & Vermont Example
Regional Susceptibility of Northeastern Lakes to Zebra Mussel Invasion Abstract