SIR Biology Investigation Abstract
BIOTIC INDICES: UTILIZATION AND INTERPRETATION OF THE MCI AND IBI RESULTS OF THE BIG ROCK CREEK WATERSHED
Presenter:
Ashley Medina, Illinois Mathematics and Science Academy
Advisor:
Mr. Roger Klocek, Shedd Aquarium
Abstract:
The Mussel Classification Index and Index of Biotic Integrity employ Unionidae and Fish populations, respectively, as indicators of environmental status. Decisions to put forth conservation efforts for a particular ecosystem often take biotic ratings into account. Results of fifteen IDNR-conducted surveys in the same sub-basin demonstrate that the IBI and MCI scores do not correlate. In repeated instances, mussel populations would indicate a wide class range, while the IBI (fish) results would remain stable. These anomalies imply that fish and mussel populations do not reflect the same stressors, or else respond in drastically different manners, despite that they may be fair qualitative indicators of environmental change. This may lead to misinterpretation of the index scores. The parameters measured in each index are derived only from the species abundance, richness, age distribution, extant intolerant species, and catch per unit effort of the site; neither takes other factors into account. Biotic index scores yield only a snapshot of the measured populations of a single ecosystem, and do not reflect the numerous factors that influence the surveyed assemblages. The next step of this research would be to analyze other streams and determine if this lack of correlation is universal, or unique to the sub-basin surveyed.