11.3 - Sampling techniques Flashcards
Why is it important to use different sampling techniques in a habitat?
Different techniques collect different types of data. Multiple techniques improve accuracy by providing a range of information about species presence, abundance, and habitat conditions.
What are the key principles of ethical sampling of animals?
- Handle organisms carefully to prevent harm.
- Minimize stress by limiting the time they are held.
- Return organisms to the exact location they were found.
What is a pooter, and how is it used?
A pooter is a device used to catch small insects by sucking air through a mouthpiece. A filter prevents insects from being inhaled.
What are sweep nets used for?
Sweep nets are used to catch insects in long grass by sweeping the net through vegetation.
What are pitfall traps used for? What adaptations have to be made to it?
Pitfall traps are holes dug in the ground to trap crawling invertebrates (e.g., beetles, spiders, slugs).
- Must be deep enough to prevent escape.
- Covered with a roof structure to prevent flooding.
- Typically left overnight to sample nocturnal species.
What is tree beating?
Tree beating is a method used to collect invertebrates from trees or bushes.
1. A white cloth is placed under a tree.
2. The tree is shaken or beaten, causing invertebrates to fall onto the cloth.
What is kick sampling, and when is it used?
Kick sampling is used to study organisms in rivers.
- The riverbed is kicked to disturb sediment.
- A net downstream collects dislodged organisms.
What is a quadrat, and what is it used for?
A quadrat is a square frame used to sample plants and slow-moving animals (e.g., limpets, barnacles, mussels, sea anemones).
What are the two types of quadrats?
- Point quadrat – A frame with a horizontal bar. Pins are inserted through the bar, and each species touched is recorded.
- Frame quadrat – A square grid where species within each section are counted.
How can quadrats be used systematically?
Quadrats can be placed along a line or belt transect to measure how species distribution changes across an area.
What is species richness?
Species richness is the number of different species found in a habitat.
How is species richness measured?
- Identify all species in a habitat using sampling techniques.
- List and count the total number of species found.
- Use identification keys to classify organisms accurately.
What is species evenness?
Species evenness describes how similar the population sizes of different species are in a habitat.
How is species evenness measured?
By comparing the total number of individuals per species.
- A habitat where species populations are similar in size has high evenness.
- A habitat dominated by one species has low evenness.
What are the three ways of using a frame quadrat to sample plant populations?
- Density – Count individuals in a 1m² quadrat to get absolute numbers per square meter.
- Frequency – Count how many grid squares a species appears in and express as a percentage.
- Percentage cover – Estimate the total area covered by a species in the quadrat.
How can quadrat sampling be used to estimate total population size?
- Calculate the mean number per m².
- Multiply by the total area of the habitat.
What is the capture-mark-release-recapture method?
- Capture as many individuals as possible.
- Mark them in a non-harmful way.
- Release them back into the habitat.
- After time for redistribution, recapture a second sample.
- Compare the number of marked vs. unmarked individuals to estimate population size.
What does a high number of recaptured marked individuals indicate?
A small population size, as fewer new individuals were captured.
How is species evenness calculated using animal populations?
- If all species have similar population sizes, the community is even.
- If one species dominates, the community is uneven.
- Expressed as a ratio between species numbers.
What are abiotic factors?
Non-living environmental conditions that affect organisms, such as light, temperature, and oxygen levels.
List the 6 abiotic factors.
- Wind Speed
- Light Intensity
- Humidity
- pH
- Temperature
- Oxygen in Water
What sensor is used to measure each of the six abiotic factors.
- Wind Speed –> Anemometer
- Light Intensity –> Light meter
- Humidity –> Humidity Sensor
- pH –> pH Probe
- Temperature –> Temperature probe
- Oxygen in Water –> Dissolved oxygen probe
What unit of measure is used for each of the six abiotic factors?
- Wind Speed –> ms⁻¹
- Light Intensity –> Lux (lx)
- Humidity –> mg dm⁻³
- pH –> pH
- Temperature –> °C
- Oxygen in Water –> mg dm⁻³
What are the advantages of using sensors to measure abiotic factors?
- Detect rapid changes in the environment.
- Reduce human error in readings.
- Increase precision of measurements.
- Allow data storage & tracking over time.
