Carry out a quantitive survey of plants in an ecosystem Flashcards
The local area of study is called?
A habitat
Name the 2 methods of calculating the numbers of each species.
subjective estimates and objective estimates
What are subjective estimates?
involve an individual judgement as to how numerous each type of species is in the habitat
Why are subjective estimates flawed?
people may have different estimates for the same species in a habitat
What are objective estimates, how are they better?
they do not rely on individual judgements
What is used in objective estimates to provide an objective estimate?
quadrat
What is a quadrat?
a square made of metal/wood/plastic, typically sides of 1m, 0.5m or 0.25m
Give 4 steps of using a quadrat.
1) thrown at random
2) count number of plants that are in the quadrat
3) repeat a number of times
4) correct calculation is described
Instead of throwing a quadrat what can you do?
lay them out in a line across part of the habitat
Give 2 limitations of quadrants.
1) fast-moving animals won’t remain in the quadrat.
2) size of the species
What two measurements are taken within each quadrat?
percentage cover and frequency
Whats the percentage cover?
an estimate of the amount of ground in a quadrat covered by each species
Definition of frequency?
the chance of finding a named species with any one throw of a quadrat
What are transects used for?
used where changes along a gradient are suspected, e.g. across a rocky seashore
Name two types of transects.
line and belt
