In species–area relationship, regression co-efficient or Z, lies in the range of $0.1\mathrm{ }\mathrm{t}\mathrm{o}\mathrm{ }0.2$, regardless of the taxonomic group or the region. In the species-area relationships among very large areas like the entire continents, Z values are in the range of $0.6\mathrm{ }\mathrm{t}\mathrm{o}\mathrm{ }1.2$. For frugivorous birds in the tropical forests of different continents, the value of Z is $\mathrm{1.15.}$