West Nishnabotna River Malvern
Analysis Summary for Series #1990
Benthic Macroinvertebrate Index of Biotic Integrity (BMIBI)
| Metric Name | Value | Score |
|---|---|---|
| MH Total Taxa | 14 | 2.69 |
| SH Total Taxa | 10 | 4.41 |
| MH EPT Taxa | 7 | 2.59 |
| SH EPT Taxa | 7 | 4.76 |
| MH Sensitive Taxa | 4 | 3.64 |
| SH Ephem % | 17.31 | 2.21 |
| SH EPT % | 96.15 | 10 |
| SH Chiron % | 1.92 | 9.91 |
| SH Scraper % | 0 | 0 |
| SH Top3Dom % | 81.73 | 2.9 |
| SH Dom FFG % | 75.96 | 4.01 |
| MHBI | 6.07 | 3.44 |
| *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 | 9/7/2016 |
| Sampling Series | Series #1990 |
| Drainage Area (mi2) | 967 |
| Log(DA) | 2.985426474083 |
| Calculation Last Updated | 10/28/2025 3:00:11 PM |
| Sampling Gear | Float ArtSub |
Sessions used in this analysis
Warm Water
Fair
Only two art subs present. Plates appeared to be scoured by high flow.
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and habitat specialists are rare; EPT taxa are still dominant in abundance; however, the most-sensitive EPT taxa have been replaced by ept taxa that are more tolerant of organic enrichment; the community is not well-balanced; a few taxa clearly dominate in abundance, collector-gatherers or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 survey site. Survey sites are compared to reference sites within the same ecoregion. A reference site represents natural stream qualities that are least disturbed by human activities within the watershed. Reference sites are grouped by ecoregion to establish a benchmark against which these survey streams are compared.
EcoRegion Comparison
Scores for a sampling session are compared against reference sites within the same ecoregion:
| Max | 72 |
| 75th Percentile | 61 |
| Median | 53 |
| 25th Percentile | 47 |
| Min | 28 |
| This Session's Score | 42 |
| Total Reference Site Samples | 37 |
| Mean | 53.73 |
| Standard Deviation | 10.44 |