Unnamed Tributary to Little Sioux River Bertram Reservation - Peterson (HW86)
Analysis Summary for Series #1546
Benthic Macroinvertebrate Index of Biotic Integrity (BMIBI)
| Metric Name | Value | Score |
|---|---|---|
| MH Total Taxa | 17 | 5.53 |
| SH Total Taxa | 11 | 9.29 |
| MH EPT Taxa | 4 | 2.74 |
| SH EPT Taxa | 3 | 3.8 |
| MH Sensitive Taxa | 1 | 1.56 |
| SH Ephem % | 0.33 | 0.04 |
| SH EPT % | 7.38 | 0.77 |
| SH Chiron % | 44.99 | 5.56 |
| SH Scraper % | 39.11 | 8.75 |
| SH Top3Dom % | 83.15 | 5.25 |
| SH Dom FFG % | 52.47 | 7.92 |
| MHBI | 6.62 | 1.41 |
| *Mouse-over metric for full name | ||
| **Final IBI is sum of scores multiplied by 0.8333 | ||
Analysis Factors
| Factor | Value |
|---|---|
| BMIBI Type | Warm Water |
| Sample Date | 8/13/2013 |
| Sampling Series | Series #1546 |
| Drainage Area (mi2) | 7.304 |
| Log(DA) | 0.863560764526243 |
| Calculation Last Updated | 7/22/2025 3:36:37 PM |
| Sampling Gear | Surb |
Sessions used in this analysis
Warm Water
Fair
Macroinvertebrate densities were extremely low throughout the reach, including the cobble riffle.
BMIBI Score Explained
This site was analyzed using the BMIBI-Warm Water assessment methodology.
Sites that score between 31 - 55 are considered fair. Total taxa richness and EPT (Ephemeroptera, Plecoptera, Trichoptera) taxa richness are noticeably reduced from optimum levels; sensitive species and habitat specialists are rare; EPT taxa are still dominant in abundance; however, the most-sensitive EPT taxa have been replaced by ept taxa that are more tolerant of organic enrichment; the community is not well-balanced; a few taxa clearly dominate in abundance, collector-gatherers or collector-filterers often comprise more than 50% of the community.
This location has been classified as a Candidate Reference Site. Further study is required to determine if this site represents natural stream qualities that are least disturbed by human activities within the watershed.
EcoRegion Comparison
Scores for a sampling session are compared against reference sites within the same ecoregion:
| Max | 88 |
| 75th Percentile | 58 |
| Median | 51 |
| 25th Percentile | 45 |
| Min | 10 |
| This Session's Score | 44 |
| Total Reference Site Samples | 45 |
| Mean | 50.91 |
| Standard Deviation | 13.26 |