sampling

Maintenance of conditions

done in uniform areas to eliminate bias

Line transects

examine change over distance

large number of samples

30 +

non-motile/slow moving

Plants, snails and non moving organisms’

motile organisms

moving/active organism animals etc.

how non motile organisms are sampled

using a quadrat in a random sample (uniform distribution) or a line transect (uneven distribution)

random sampling methods

-line two tape measures at a right angle to create a gridded area

-use a random number generator to generate two coordinates

-Place the quadrat and collect the data using percentage cover or frequency

-take over 30 different samples

Line Transects

-uneven distribution of organisms (beaches, rocky shore)

-measures across an entire area and is not random

-belt and interrupted belt transects

Line transects method

-place the tape measure at a right angle to the shore line

-place the quadrat every 5 metres/every position

-collect data percentage cover etc

-Repeat by placing another 30 transects along the beach at a right angle to the shore line

local frequency

number of square which have species present (%)

-quick, poor accuracy

density

number of one species in a given area (actual number of species)

accurate, time consuming

percentage cover

estimate how many squares are completely covered by organisms

quicker and more effective than density with moss lichen etc., subjective