Ecological sampling of terrestrial invertebrates Flashcards
What are the major groups of terrestrial invertebrates?
*Panarthropods
Tardigrades
Onychophora-Shoot webs of slime to capture prey
Arthropods-Largest phylum of animals!#
*Arthropods
Chelicerates: spiders, scorpions, harvestmen and their allies
Crustaceans
Myriapods
Hexapods & insects
*Annelids
Polychaetes (mostly marine)
*Molluscs
What is a Pooter?
Sucking device
Used in combo with other methods
Name sampling methods
pooter device
Sweep-netting -Vegetation,Typical orders captured, Semi-quantitative only, flying insects
Aerial kite net-Flying insects
Barrier trap-Flying insects
Malaise trap-Flying insects, Excellent for some difficult groups, Can be used more quantitatively
Light trap-Moths will draw insects in from a wider area
Treacling-Moths, Mainly used for fun & education
Pitfall trap-Can be used quantitatively, Safety issues, Avoiding harm to other wildlife
Arboreal pitfall trap- Difficult to set up – climbing or catapulting.
Beating- Semi-quantitative method
Kick-sampling-Crucial method for consultants, Extremely useful for measuring water quality, RIVPACS/RICT, Standard methodologies
Bait traps-Often useful for pest organisms, Will draw insects in from a wider area (dispersal/density estimates)
Pheromone traps-Often useful for pest organisms, Will draw insects in from a wider area (dispersal/density estimates)
Pan traps
Suction sampling
What is RICT & RIVPACS
River Invertebrate Classification Tool
River Invertebrate Prediction and Classification System
Describe random sampling
What?
Take a lot of samples of individuals/different positions within a habitat
Select the individuals/sites etc to be sampled at random – each individual/point in the area should have an equal chance of being sampled
When?
Limited time – can’t sample every individual
Fairly uniform habitat
Habitat very large
How?
Use random number generator to select individuals, a point in time or a point in space
Describe Stratified sample
What?
Divide into areas and sample randomly (as above) within them
When?
When random sampling may not cover all areas equally
If there is structure to the habitat
How?
Number of samples proportional to size of area, or
Means are weighted by extent of sampling in each area after data collection, or Put more sampling effort into ‘strata’ that are more heterogeneous
Describe a Cluster sample
What?
Allocate primary sampling areas and take clusters of samples within these at random
When?
When sampling is in a dangerous area to work in
If it is hard to move from sample point to sample point
How?
Cluster areas are the same size
Number of samples in each cluster is the same
Put more sampling effort into ‘strata’ that are more heterogeneous
Describe Systematic sample
What?
Taking samples at regular fixed intervals (in time or space)
When?
Usually across a gradient
Statistical problem is that the sample isn’t random (each point does not have an equal chance of being sampled)
How?
Divide period of time and take observation once e.g. every 5 mins
Make a transect and sample once every 20m
Glossary of key terms
Random sampling-> select individuals or locations to be sampled in a random fashion
Stratified random sampling-> select individuals or locations to be sampled in a random fashion, but do this within habitat features that you have previously identified
Systematic sampling-> take samples in a fixed pattern in space or time. This is often done along transects or in grids. Transects can be useful across environmental gradients
Cluster sampling-> allocate specific sampling areas in challenging, dangerous or otherwise difficult sampling locations
