9701591 Palmer Stream environments are difficult to fully understand because food and living space tend to be distributed in an uneven way, and animals move extensively within the environment. These are factors which have lately received much attention separately, but not together. In particular, many theoretical studies assume either that animals move at random, or that they have perfect knowledge of their environment, and thus can determine the best location to move to. However, many animals do not fit these simplified ideas-they can control their movements to some extent but do not have extensive information about their environment. The investigators will use computer models, with varying levels of biological realism, to determine how animals move within the uneven stream environment, and how their movement affects population sizes and stability. They will also perform experiments in an artificial stream to determine how much control small stream invertebrates can exert over their movement in the face of flow. The movement patterns and population levels of small stream invertebrates have important consequences for the stream environment, because they form the base of the stream food web and are involved in the microbial processes web as well.
