What is the equation describing the relationship between species richness (S) and area (A) on a logarithmic scale?

log S = log C + Z log A

The correct answer is Option (1) - log S = log C + Z log A

Alexander von Humboldt observed that within a region, species richness increased with increasing explored area, but only up to a certain limit. This relationship between species richness and area was found to be a rectangular hyperbola for a wide variety of taxa, such as angiosperm plants, birds, bats, and freshwater fishes. When represented on a logarithmic scale, the relationship is described by the equation "log S = log C + Z log A."

In this equation:

• S represents species richness, which is the number of different species present in a given area.
• A represents the area explored or sampled.
• Z represents the slope of the line on the logarithmic scale, which is also known as the regression coefficient.
• C represents the Y-intercept of the line.

Regardless of the taxonomic group or the region being studied, ecologists have discovered that the value of Z lies in the range of 0.1 to 0.2. This indicates that the relationship between species richness and area follows a consistent pattern across different taxa and regions. For example, whether studying plants in Britain, birds in California, or molluscs in New York state, the slopes of the regression line are remarkably similar, falling within the range of 0.1 to 0.2.