A long-term field study in a natural English grassland looked at the effects of an annual nitrogen fertilizer addition on the species' composition of the grassland. Throughout the experiment the total abundance of all grasses together remained roughly constant, and the following data were observed: Compared to 1872, the 1949 grassland community shows________________.

Question

A long-term field study in a natural English grassland looked at the effects of an annual nitrogen fertilizer addition on the species' composition of the grassland. Throughout the experiment the total abundance of all grasses together remained roughly constant, and the following data were observed:  Compared to 1872, the 1949 grassland community shows________________.

Quizplus · Accepted Answer

The decrease in Shannon diversity index from 1.64 in 1872 to 1.45 in 1949 suggests a decrease in species evenness, indicating that the addition of nitrogen fertilizer led to an imbalance in species composition, favoring certain species over others. The total abundance of grasses remaining constant suggests that there was no increase in productivity.

A Long-Term Field Study in a Natural English Grassland Looked