please explain the graph of species area relationship? what representing the two lines(curve and stariaght indicates)?
The species area graph is a relationship between area of a habitat and the number of species found there. It is usually constructed for a type of organisms occupying a particular trophic level. A wide range of factors determines the slope of this curve including: immigration, extinction, predator prey dynamics , clustering etc.
Alexander von Humboldt observed that biodiversity increases with increase in explored area. This relationship can be given by,
log S = log C + Z log A
Where,
S = Species richness
A = Area
Z = Slope of the line (regression co-efficient)
C = Y-intercept
Value of Z is found to lie in the range of 0.1 to 0.2 for comparatively smaller areas such as countries while for very large areas such as entire continents, the slope of the line is much steeper with Z value lying from 0.6 to 1.2.
Alexander von Humboldt observed that biodiversity increases with increase in explored area. This relationship can be given by,
log S = log C + Z log A
Where,
S = Species richness
A = Area
Z = Slope of the line (regression co-efficient)
C = Y-intercept
Value of Z is found to lie in the range of 0.1 to 0.2 for comparatively smaller areas such as countries while for very large areas such as entire continents, the slope of the line is much steeper with Z value lying from 0.6 to 1.2.