Questions and Answers
What is the aim of sampling?
What is stratified sampling?
A process of identifying and sampling different areas within an overall habitat that may be very different from each other.
Stratified sampling always requires a larger sample size.
False
What is one advantage of stratified sampling?
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What is a disadvantage of stratified sampling?
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List the six key points of classification processes.
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What is the purpose of ecological surveying?
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Ecological surveying techniques do not depend on the uniformity of the area being sampled.
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What are some advantages of using transects?
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What is a common disadvantage of transects?
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What is a method to reduce sampling bias?
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What are sweep nets used for?
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What is the function of pitfall traps?
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What is the Mark-Release-Recapture technique used for?
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How is standard deviation important in ecological data analysis?
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What does the standard error of the mean indicate?
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Define old growth forests.
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Productive soils only consist of organic materials.
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What is the significance of coral reefs?
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What factors are essential when classifying ecosystems for management?
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What must be calibrated before sampling occurs?
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Study Notes
Sampling
- Aims to select a representative sample from a population using random or systematic methods.
Stratified Sampling
- Involves identifying distinct areas (strata) within a habitat for separate sampling.
- Necessary when habitat diversity is significant; not needed for uniform habitats.
- Proportional observations taken from each stratum.
Advantages of Stratified Sampling
- Ensures representation from all areas, enhancing precision.
- Requires fewer samples, thus saving resources.
- Reduces estimation error if strata have low standard deviation.
Disadvantages of Stratified Sampling
- Requires prior knowledge of different strata.
- Risks overlooking rare habitats.
Key Points in Sampling
- Purpose: Define the measurable goals of sampling.
- Site selection: Must be clearly marked for future comparisons.
- Choice of techniques: Selecting ecological surveying methods.
- Minimizing bias: Ensuring unbiased sample collection.
- Presentation methods: Effective data presentation techniques.
- Analysis: Assessing the collected data.
Purpose of Ecological Sampling
- Estimate population metrics, like density and distribution.
- Assess environmental gradients and their impact on organisms.
Site Selection
- Important for accurate location recording to enable temporal surveys.
Ecological Surveying Techniques - Quadrats
- Defined areas used for surveying organisms; typically square.
- Suitable for uniform areas; considerations include size, number, and placement.
- Data collection methods include density, frequency, and percentage cover.
Ecological Surveying Techniques - Transects
- Sampling lines used to evaluate changes over distance.
- Types include line transects, belt transects, interrupted and ladder belt transects.
Advantages of Transects
- Visual representation of ecological changes along gradients.
- Quick, easy, cost-effective, and minimizes disturbance.
Disadvantages of Transects
- Less effective for fast-moving species or dense vegetation.
- May miss low-density species.
Reducing Sampling Bias
- Increase sample size to enhance representativeness.
- Random number generators mitigate human bias in sampling.
Random Sampling Bias - Counting Criteria
- Establish clear rules for organism counting to ensure consistency and avoid overestimation.
Random Sampling Bias - Equipment Calibration
- Regularly calibrate equipment for accurate abiotic data collection.
Sampling Tools
- Sweep Nets: Capture invertebrates in tall grass.
- Drift Nets: Fixed nets for aquatic organisms.
- Mist Nets: Capture birds/bats for tagging.
- Beating Trays: Collect invertebrates by beating vegetation.
- Pitfall Traps: Capture small organisms in jars buried at soil level.
- Longworth Traps: Designed for small mammals.
- Pooters: Capture individual invertebrates.
Mark-Release-Recapture Technique
- Estimate mobile population sizes through capture-mark-recapture methodology using the Lincoln Index.
Data Presentation
- Present collected data through tables, graphs, or diagrams to aid in analyzing ecosystems or relationships between species.
Analysis of Data
- Apply confidence intervals and standard error to evaluate the reliability of means.
Standard Deviation
- Measures variation in data; key for calculating standard error.
Standard Error
- Indicates accuracy of sample mean estimates; calculated as standard deviation divided by the square root of the sample size.
Holdridge Lifezone Classification System
- Classifies ecosystems based on rainfall, temperature, evapotranspiration, latitude, and humidity.
Specht's Classification System
- Identifies lifeform types in the tallest stratum based on vegetation characteristics.
Australian National Aquatic Ecosystem (ANAE) System
- Classifies aquatic ecosystems in three levels for ecological diversity assessment.
European Nature Information (EUNIS) System
- Comprehensive habitat classification for Europe, covering all habitat types.
Ecosystem Management
- Classifying ecosystems aids decision-making for management practices.
- Enhances understanding of ecosystem interactions and the effects of human impacts.
Old Growth Forests
- Mature forests with negligible disturbance, featuring large, old trees and rich biodiversity.
- Important for cultural and ecological conservation.
Management Strategies for Old Growth Forests
- Implement prescribed burning, control exotic species, special harvest plans, and recreational policies.
Productive Soils
- Composed of varied grain sizes, minerals, and organic matter supporting plant growth.
- Key for agricultural profitability and ecosystem health.
Management Strategies for Productive Soils
- Minimize overgrazing, select suitable crops, and apply appropriate land preparation methods.
Coral Reefs
- Critical for coastal protection, providing habitat and nutrients for marine life.
- Economic significance in fishing and tourism.
Management Strategies for Coral Reefs
- Develop zoning plans and enforce removal of exotic species to protect ecosystems.
Exam Questions Insights
- Describe old-growth forests and productive soils emphasizing their characteristics and ecological importance.
- Importance of reliable abiotic and biotic data for ecosystem management classifications.
- Classification aids in informed management of resources and sustainable practices.
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Description
This quiz covers concepts related to sampling methods, including general sampling and stratified sampling techniques. It is designed to enhance understanding of how to select representative samples in various populations. Perfect for students studying classification processes.