Biology - Quadrat sampling calculation

熙の琰狐枫

各位老大～
请问Quadrat sampling的 calculation到底要怎么算？
就比如 relative frequency 要怎么算呢？
可以帮忙解释么？
谢谢各位～感激感激～

darksider

If you are using quadrat sampling and your quadrat is divided into grids, then


Frequency is the chance of finding a given species within a sample
Frequency of species A  = number of quadrats containing species A / total number of quadrats
Relative frequency = frequency of species A / sum of frequency of all species

Density of A = number of species found within a population / volume of population
Relative density of A = density of species A / sum of density of all species

Coverage (C) is the proportion of the ground occupied by a vertical projection to the ground from the aerial parts of the plant
*You should know the area of the intraquadrats. Say you use a quadrat with area 100m^2. You divide it by using thread into 100 small boxes so each boxes has 1m^2 area.

The coverage area of species A = total boxes covered by species A(approximate them) / total area of the quadrat
Relative coverage area of species A= coverage area of species A / total coverage area of all species

If you are not dividing them into small boxes with known area , then the following formulae should be used
Coverage area = (sum of the basal area x density of the species ) / total number of the species in the population

Relative coverage area = coverage area of the species / total coverage area for all species