Species-Area relationship

Alexander Von Humboldt has observed that within a region, species richness increased with increased explored area, but only upto a limit.

The relationship between species richness and area for a number of taxa like angiospermic plants, freshwater fishes and birds is found to be a rectangular hyperbola.

On a log scale, the relationship becomes linear (straight line) and is described by the equation.

log S = log C + Z log A, where,

S = Species Richness Z = Slope of the line (regression coefficient)

A = area and C = y-intercept Ecoloeists have found out that the value of Z-hne ranges between 0.1 and 0.2 irrespective of the taxonomic group or the region.

But this analysis in very large areas like a continent, the Z value ranges between 0.6 and 1.2.

The Z value for frugivorous birds and mammals in the tropical forests is found to be 1.15.

Species area relationship