10.1 6 Ecological Techniques Flashcards
Abundance of an organism
The relative representation of a species in a particular ecosystem
Number of an organisms relative to the number of other organisms in the same habitat
Distribution of an organism
Where a species is found in the environment and how it is arranged
Can change e.g. Migration
Uniform distribution
Resources are thinly but evenly spread
Or When individuals of a species are antagonistic to each other
Clumped distribution
Herds of animals or groups of plants that have a specific resource requirement and therefore clump in those areas where resources are found
Random distribution
Result of plentiful resources and no antagonism
Quadrants
Sample an area Plants and animal don't move much Usually 50cm as easy to handle Quantitative sampling Individual counts or percentage cover
Individual counts
The number of individual organisms in an area
Percentage cover
The area covered by the above ground parts of a particular species
Limitations of quadrats
Limitations to area you can sample
The randomness of sampling side
Decisions whether to include organisms partly covered by the quadrat
ACFOR
A= abundant C= common F= frequent O= occasional R= rare
Limitations of ACFOR scale
Subjective
No set definitions of terms
Species easily rated by how obvious they are rather than how abundant they are
Point quadrat
Horizontal bare supported by two or three legs
At set intervals along bar holes which a long pin is dropped
Species that touch pins are recorded
Quadrats used to randomly sample areas
Placing them at random coordinates or simply throwing them in a given area
Line transects
Stretch tape between two points record every individual that touches the tape
Not random
Belt transect
Two tapes are laid out and grown between them are surveyed
