What did Alexander von Humboldt observe about species richness and explored area in South American jungles?

Species richness increased with increasing explored area up to a limit.

b) Species richness increased with increasing explored area up to a limit.

Alexander von Humboldt observed that within a region, species richness increased with increasing explored area, but only up to a certain limit. In other words, as the area explored in the South American jungles increased, more species were discovered until a point where further exploration did not significantly add to the number of species found.

This pattern is known as the species-area relationship, and it is often represented by a rectangular hyperbola, where species richness initially increases rapidly with area and then levels off as the explored area becomes larger.