Research Methods Flashcards
What does accuracy mean?
A measure of how close the recorded result is to the real value.
What does precision mean?
The intervals between possible recorded results e.g. a ruler that measures in millimetres is more precise then one that measures in centimetres.
What is a representative sample?
A subsample that accurately reflects the complete data set
What is a reliable method?
Provides consistent, accurate results
What is an anomalous result?
A result that differs from other results with which it was expected to be similar. Repeating the study should show weather it is a real result or was caused by other variables.
What is a valid study?
Produces precise, accurate, reliable, results upon which conclusions can be based.
What are the components of carrying out scientific fieldwork?
- Appropriate risk assessment
- Practical equipment and materials required and how to use safely
- Data to be collected and analysed:
- using appropriate apparatus to record quantities measurements and to measure biotic/abiotc factors
- selecting the correct sampling techniques
- selecting the correct statistical test
What are the general principles of scientific research?
- Identifying a topic of interest
- Finding out what has already been learnt
- Formulating a hypothesis and null hypothesis
- Designing and carrying out an experiment to test the hypothesis
- Designing the investigation = sampling location, time, size of sample, standardised technique, stats test
- Analysing the results and drawing conclusions
- Planning further research needed to fill gaps in existing knowledge
When sampling why does sample location matter?
To avoid the introduction of bias caused by the deliberate selection of locations for the convenience or to support or dismiss a hypothesis.
What is random sampling?
If the study has a regular shape then a grid can be laid out and the coordinates of sampling sites selected using random numbers.
If the study area has an irregular shape then all the possible sampling sites can be numbered and selected using a number generator.
What is systematic sampling?
This involves samples taken using a chosen interval distance or spacing. The choice of sampling sites is not based on choices made by observable differences in the study area.
Distance between sampling sites should be selected to detect variability without collecting more data then necessary, this can be determined using a preliminary study.
When sampling why does sample timing matter?
If the factor being measured changes with time, then it will be necessary to sample on different occasions to produce a mean result that represents the typical value.
Ideally time intervals depend on the rate at which valued change = preliminary study
When sampling why does sample size matter?
If the variable is not homogenous then larger samples are more likely to produce representative results.
- preliminary study
When sampling why does the number of samples matter?
The number of samples needed to produce a representative mean depends upon the degree of scatter around the mean.
The degree of scatter values around the mean can be assessed using the Standard Deviation.
It is easier to assess the degree of statistical significance of the results with larger sample sizes.
When sampling why does standardising the techniques matter?
To allow comparison of the results that are collected at different times, in different locations or by different researchers, they must all be collected in exactly the same way.
Why are good surveys essential for wildlife conservation programmes?
- to find out which species are present
- to monitor the habitat conditions, how the change etc
- to monitor features of populations and how they change over time such as:
- population size
- age structure
- growth rates
- breeding rates
- territory size
- populations movements
What is a quadrat and what is it used for?
It is a study area, within which populations can be studied.
The results from many quadrats can be scaled up to estimate the overall situation for an entire area
What size should a quadrat be?
Lichens = 10cm x 10cm
Ground flora = 0.5m x 0.5m
Trees in a forest = 100m x 100m
Bird presence survey = 10km x 10km
What are the three types of quadrats?
- Open quadrats = mark out a study area
- Grid quadrats = sub divided into smaller squares e.g. 10 x 10 each representing 1%
- Point quadrats = used when ground flora is too tall and would be flattened by others quadrats, a wooden frame supports 10 metal rods, each time a rod touches a leaf it counts as 10% cover
What are the limitations of quadrats?
- Subjective judgement may be involved
- Quadrat frame may flattery or move plants
What is a pond net and the method to use it?
Pond nets sweep through water or aquatic vegetation to capture invertebrates, amphibians or fish
- using a particular sweep length or number of sweeps can help to standardise the method
What are the limitations of pond nets?
Mobile species may escape
What is kick sampling and what is the method to use it?
Kick sampling collects invertebrates that live on river beds
- net with its straight edge on the river bed and its face open to the current
- riverbed in front of the net is disturbed by kicking a boot over it
- controlling the number of of kicks and length of kick can be used to standardise it
What are the limitations of kick sampling?
- accurate standardisation is difficult
- buried organism of those fixed to stones may not be dislodged
- some organisms can swim and avoid the net
- water flow rate is variable
- fragile organisms can be destroyed
What is a surber samples and what is method to use it?
Provide a more standardised technique
- fixed are of riverbed is sample with a box-like frame
- river bed is disturbed using a trowel and stones are inspected manually
- netting at the side of the net opening reduces the number or organisms that escape
What are the limitations of surber samplers?
- can only be used where the water flow is fast enough to carry organisms
- samplers small size can make it difficult to set on rough substrates in deep water
What is a plankton net and what is the method to use it?
Catch planktonic organisms floating in water
- a fine mesh is pulled trough the water and can be used vertically or horizontally
- net can be fixed where there is a current or towed
What are the limitations of a plankton net?
- nets with course mesh size do not catch smaller organisms
- nets with a fine mesh may become clogged by phytoplankton, preventing water flowing through the net
What is a sweep net and what is the method to use it?
- sturdy best used to sample invertebrates in ground vegetation such as grassland, it is swept so the organisms are dislodged and caught
- standardisation = same number of sweeps and length of sweep
What are the limitations of sweep nets?
- mobile species may escape such as flying insects
What are aerial insect nets and what is the method to use them?
These are lightweight nets used to capture flying insects such as butterflies
What are the limitations of aerial insect nets?
Successful collection depends on the agility of the researcher and prey
What is colonisation media and what is the method to use it?
Some species can be monitored by providing suitable habitats that they may colonise
What are the limitations of colonisation media?
- not all species can be monitored as they may not use the media
- accurate population estimates are not possible as the proportion that colonise the media is not known
What are pitfall traps and what is the method to use it?
Pitfall traps are used to sample mobile animals on the ground surface
- container is place on a hole with its open end making a close fit with the soil and the top being level with the ground surface
- a cover supported over the opening stops predators, or rain getting in
- trap is checked after a standard period of time
- a preservative fluid may be used to kill animals for later study
What are the limitations of pitfall traps?
- only mobile organisms
- trapped carnivorous animals may kill other organisms
- preservative may attract or repel certain species
- some species avoid traps or can escape
What is a beating tray and what is the method to use it?
Used to sample invertebrates present of vegetation above the ground
- tray is placed under the vegetation which is beaten several times, invertebrates are dislodged and collected on the tray
What are the limitations of beating trays?
- difficult to standardise
- some species are not dislodged
- some species fly away
- higher branches cannot be reached
- thicker branches shake less
What is a light trap and what is the method to use it?
Used to collect night-flying insects that are attracted to bright lights
- fall into a container, after being attracted to light (UV)
What are the limitations of a light trap?
- moths only fly during their adult phase and activity is affected by weather and seasons
- hard to compare traps with different brightnesses
What is a tullgren funnel and what is the method to use it?
Used to sample mobile invertebrates in leaf litter or soil
- sample of leaf litter or soil placed onto mesh beneath light
- the light and heat repel the mobile invertebrates which move down through the mesh and fall into a container
What are the limitations of a tullgren funnel?
- only species repelled by heat and light will be collected
- some may die
- some are too large
What are suction samples are what is the method to use it?
Used to capture airborne insects that were dislodged from vegetation
- air suction captures flying insects
- motor driven can be used to sample invertebrates on ground vegetation
- Pooter is used to pick up vertebrates that have been found and are in a tray
What are the limitations of suction samplers?
- may sense the air sampler and fly away
- some may nit be dislodged by the suction
In terms of earthworm extraction from soil what is soil flooding and how do you do it?
- mark out an area
- remove vegetation
- add irritant e.g. mustard water
- keep adding till soil is saturated
- saturate the surrounding area
- collect worms that surface
- continue collecting until no more worms appear fora time period
- count and measure
What are the limitations of soil flooding?
- irritant may not percolate through impermeable soils
- irritant may not reach deepest worms
- worms may move down or sideways
- worms may not move
- worms may die
- worms may move too slowly
In terms of earthworm extraction from soil what is soil pit extraction?
A pit of a chosen area and depth is dug up
- soil is hand sorted and worms collected
What are the limitations of soil pit extraction?
- smaller worms may be overlooked
- digging may disturb worms and they may move down or sideways
What is population size/density?
To estimate the numbers of organisms of a particular species within a population or per unit area
What is abundance scales?
Involve allocating species to different categories based on their relative abundance e.g. the DAFOR scale:
- Dominant
- Abundant
- Frequent
- Occasional
- Rare
What is species richness/diversity?
A measure of the number of different species found in an area, often focusing on a particular taxonomy e.g. birds, or reptiles
What is species frequency?
A measure of the dispersal of a species by recording the proportion of al samples in which it was found
A high species frequency shows the species is generally distributed
What is species density?
The number of species found to a specific area and makes species richness results more comparable e.g. number of species per square metre
What is percentage vegetation cover?
Estimated by observing the proportion of:
- ground that is covered by vegetation or ground flora
- sky that is obscured by vegetation for tree cover
- grid quadrats are usually used
What is Lincoln index? And capture recapture?
Estimates the total population by catching a proportion of the population:
- sample is caught, counted, marked, released
- appropriate amount of time later, a second sample is caught and counted, and marked individuals are counted
- Lincoln index used to estimate population
number in 1st sample x number in 2nd sample Total population = —————————————————————
Number in second sample with marks
What are the limitations of Lincoln’s index?
Relies on assumptions:
- animals are all mobile and can be caught
- size of population doesn’t change due to deaths, births, immigration, emigration
- being caught and marked doesn’t affect their rate of survival
- marked individual properly reintegration
- all individuals have the same chance of being caught
What is Sampson’s index of biodiversity?
Used to asses the variety and abundance of species in an area.
N(N-1)
D = ————
Sum of(n(n-1))
N = total number of individuals of all species
N = number of individuals of a particular species
What are species identification: ID keys?
Often dichotomous keys where a sequence of questions narrows sown the possibilities
Based on unique visible features: size, shape, markings
What are the limitations of ID keys?
- some species lack characteristic features and look the same as other species
- characteristic features may not always be present
How are image databases used as a specialist technique in ecological research?
- Individual of some species can be recognised from image databases of unique feathered e.g. tigers facial stripes, cheetah tail markings, whale shark spots, dolphin fin marks, zebra stripes.
Provides information on: - territory size
- population movements such as migrations
- lifespans
- social groupings
What are the limitations of image databases?
Few species have unique feathers that can be used to identify individual animals
How are motion-sensitive cameras used as a specialist technique in ecological research?
Used for habitat monitoring to detect the presence or activity of animals, using visible light photography or infrared at night
How are closed circuit TV (CCTV) used as a specialist technique in ecological research?
Used to observe animal behaviour with a lower risk of disturbance than if researchers visit the site e.g. birds nests
How is marking/tagging used as a specialist technique in ecological research?
Used to be able to identify individual which have already been caught, e.g. rings on birds
- provides information on lifespans and movements
How are DNA databases used as a specialist technique in ecological research?
DNA profiles can be used to identify individuals, gene pools and other genetic relationships
How can DNA databases be used to detect the presence of a species?
DNA shed into the environment can be collected this is called eDNA
- it can be used to prove a species is existing in a area and give cause to protect that area.
How can DNA databases identify regional populations?
Each separate population within a species has its own unique gene pools
- so it may be possible to identify where a plant or animal came from
- this is being used to identify the sources of timber, elephant ivory and illegal trade is coming from
How is auditory monitoring used as a specialist technique in ecological research?
Some species cannot be seen but can be detected by the sounds they produce
E.g. sonograms are records of the sounds made by taxa such as dolphins, bats and some insects
How is position monitoring used as a specialist technique in ecological research?
- radio, gps, acoustic transmitter can be used to track animals in air or freshwater
- acoustic transmitters used for seawater
- give real time information of the current position of the animal carrying the transmitter
- geolocator tags may be used where transmitters are too heavy, or battery life too short
How are data recorders used as a specialist technique in ecological research?
Collect data on a range of abiotic factors e.g. temperature, light, salinity, pressure
The data may be downloaded when the recorder is recover by radio or auditory transmission
How are sensor carrier systems used as a specialist technique in ecological research?
If data is collected in a single location then the sensor just need to be placed there but it is often necessary to have a carrier system to move the sensor to the study areas:
- ROV = remotely operated vehicles - drones
- AUV = automatic unmanned vehicles
- balloon
- aircraft
- satellite
- animals
How are satellite systems used as a specialist technique in ecological research?
- reflected visible light provides images of large areas of earths surfaces
- infrared emitted by the earth can be used to monitor vegetation density and temperature
- weather monitoring
- radar microwaves:
- wind velocity
- sea surface altitude
- wave height
- oil pollution
How is indirect evidence used as a specialist technique in ecological research?
- nets/burrows
- droppings - diet, gender, territory
- feeding marks - chewed nuts
- owl pellets - diet
- tracks/footprints
- territorial marks - scratching posts
