Fun with Science Club®


			Rivers with more energy and more habitats have more fish. Beth Tyler 05.25.01 Ecologists who study species diversity are interested in why some places have more species than other places. To figure out why some places have more species than another, they take many different measurements in an area and compare those measurements with "species richness". Some ecologists in France wanted to know what factors in a river influenced the number of species of fish living there. To do this, they collected information from many ecologists studying rivers around the world. Once they had information from 292 rivers around the world, the ecologists compared the number of species in a river with many measurements, like the river’s size, energy, and heterogeneity. Because plants provide food for many organisms in a river, ecologists measured the river’s energy by how much plants grew. They measured heterogeneity by the number of different habitats a river had. The more heterogeneous a river is, the more kinds of fish that can live there. After looking at many measurements of the river, the ecologists found that rivers with more energy and higher heterogeneity have more species of fish. Knowing this, scientists can predict the number of fish species in a river by knowing about that river’s energy and heterogeneity.


			Guegan, Jean-Francois, Sovan Lek, and Thierry Oberdorff. 1998. Energy availability and habitat heterogeneity predict global riverine fish diversity. Nature 391:382-384.