Chad Rigsby, '11

Chad Rigsby '11, a major in biology, is studying stream macroinvertebrates upstream and downstream of each of the dam sites.  The objectives of his work is to understand the impact of the lowhead dams on the macroinvertebrate community.  For each lowhead dam, he is sampling the pooled area immediately upstream of the dam, an area further upstream that is unimpacted by the dam, characterized as the first riffle environment immediately upstream of the pooled area, and the downstream recovery riffle.  He is using OEPA standard operating procedures for qualitative sampling and analysis of aquatic organisms which will make data comparable to other streams in Ohio.  Chad's data will form a baseline dataset characterizing the condition of Beaver Creek and Buck Creek prior to lowhead dam modification or removal.

The larval and adult forms of the Riffle Beetle (F. Elmidae). This insect is characterized as intolerant of pollution and therefore is a great indicator of a healthy stream if found.

A Caddisfly (O. Trichoptera)  and a case. Caddisflies are also excellent indicators of good water quality. In many biomonitoring indices, the amount and diversity of caddisflies are required. On the left is a case made by a Snailcase Maker Caddislfy. Depending on the species, these organisms make cases out of plants, pebbles or they even spin their own silk!

The dorsal (back) and ventral (tummy) sides of a Water Penny (F. Psephenidae). This larval form of this insect is also a great indicator for water quality.

The data I am collecting can be summarized in a number of ways.  The graph below displays two things: first, the total amount of families (biodiversity) of organisms found at each site at the lowhead dam area and second a PTI (pollution tolerance rating) value for each of the sites. This graph suggests that biodiversity and PTI are connected, which is true. The PTI takes into account the types of organisms that are found, the different types of those organisms (for example: there are several types of caddisfly) and incorporates that information with established ratings for different organisms in terms of pollution tolerance. For example: lets say you went down to the creek and collected a caddisfly. Caddisflies are known to be very intolerant of pollution and disruption, so they are listed as “intolerant” with a value of “4”. Now lets say that you found three types of caddisflies. That would give you of 12 (3 x 4). The more intolerant organisms you find, the higher the score!