Ecological Field Methods Flashcards
name 5 ways to record vegetation
1) species presence/ absence
2) no of specimen present per species
3) biomass per species
4) species presence within subplots of quadrat
5) % ground cover of species
3 classification methods for % ground cover
braun-blanquet (1964
Domin (1923)
Londo (1976)
disadvantages of biomass analysis
(destructive, difficult & only feasable for low vegetation)
disadvantages of counting no of specimen per species
proves difficult for plants in the field; 1 tree = 1 fern?; often not clearly distinguishable
what is passive sampling
Animals are being recorded without the use of any attractor (ideally gives the exact ratio of occurrence between different species - BUT most often reflects the activity spectrum of the different species)
what is active sampling
Animals are actively attracted to the sampling device
give examples of passive sampling
plot and line transects
sweep netting
mist net sampling
pitfall jars
fogging and misting
suction traps
describe plot and line transects
All encounters with the group of interest (e.g. birds or their nests, mammals, reptiles, frogs, butterflies…) are recorded, ideally with respective distances along line transects or from certain points over a clearly defined period of time.
describe sweep netting
A strong net is swept through the vegetation at regular intervals for a regular number of times; arthropods sitting in the vegetation are collected.
describe mist net sampling
A net invisible for the animals is arranged to that the animals (birds/bats) are entangled in the net or automatically move into a special trapping area (butterflies).
describe pitfall traps
A jar is arranged in a small hole so that it just reaches
surface level and filled with liquid; sometimes also with a small funnel to prevent escapes and/or a roof against rain may be added.
describe fogging and misting
An insecticide (e.g.pyrethrin) is sprayed into the vegetation so that arthropods are knocked down and can easily be sampled in funnels/nets/ plastic sheets spread below the vegetation
describe suction traps
An airflow is produced through a metal pole, and all insects sucked into the pole are filtered – widespread in the control
of aphids.
4 examples of active sampling
light traps
bait traps
pheromone traps
water traps
describe light traps
A light source attracts nocturnal insects which are either collected manually from a cloth or automatically trapped.
e.g.: lighttower
describe bait traps
For insects, potential food sources (e.g. dead fish, rotten fruit) are put onto a plate and arranged below a net into which insects will move after feeding from the bait.
Typical mouse traps are another
example.
describe pheromone traps
Pheromones attract male insects into trapping devices, e.g. sticky surfaces or sampling jars.
describe water traps
Colourful bowls are filled with water and put on an elevated position – insects come to the trap and drown.
Which questions should be considered when selecting parameters
1) What is the relevance of each parameter
2) How can we measure each parameter without interacting or disrupting other parameter
3) How much precision do we need? (time & money)
4) How will we evaluate results for each parameter
What parameters exist when looking at habitat
habitat type, habitat size, coordinates, elevation, inclination, humidity, temperature, soil chemistry,, disturbance patterns (fire, flood), anthropogenic influence, connectivity to neighbouring ecosystems
What parameters exist when looking at plant and animal species
population size, seasonal variation, difference in size or distribution between species
what parameters exist when looking at vegetation
“species composition, structural composition (species type, not every individual species), connectivity
Autecological parameters
structural composition, life expectancy, phenology, reproduction, establishment”
what parameters exist when looking at animal communities
“species composition, structureal characterization
Autecological parameters habitat requirements (food, size etc), interspecific influences (predation, competition, mutualism, parasitism), reproduction, migration"
what parameters exist when looking at threats to ecosystem
invasive species, degradation
