Bioassessment of aquatic invertebrates along the Laramie River at Fort Laramie National Historic Site
Tronstad L. 2013. Bioassessment of aquatic invertebrates along the Laramie River at Fort Laramie National Historic Site. Natural Resource Technical Report. NPS/NGPN/NRTR—2013/823. National Park Service. Fort Collins, Colorado
The Laramie River runs through Fort Laramie National Historic Site in eastern Wyoming and is an important source of water for the area. To estimate the ecosystem quality of the Laramie River, I collected aquatic invertebrates at three sites using a Hess sampler. Invertebrates were identified and counted under a dissecting microscope. Each taxon was assigned a functional feeding group, habit, and pollution tolerance based on published values, and I calculated 24 bioassessment metrics. Total invertebrate density in the Laramie River was 21,500 ind/m2. I identified at least 49 taxa in the river and I collected about 21 taxa in each sample. Bioassessment metrics indicated that the ecosystem quality of the river was good and the sites were similar. The Laramie River had a high percent EPT taxa (53%), EPT richness (11), percent taxa intolerant to pollution (64%), and EPT/Chrionomidae ratio (2.6). Additionally, the Laramie River had a low percentage of tolerant individuals (tolerance value >8; 0.2%) and a percentage of tolerant taxa (2.4%). The average tolerance value of an invertebrate in the river was 4.82 on a scale of 0 (intolerant of pollution) to 10 (tolerant of pollution; Hilsenhoff’s Biotic Index), showing that the invertebrate assemblage was composed of a large fraction of individuals with low tolerance to pollution. Overall, the Laramie River appears to have good ecosystem quality.
- Type
- Published Report
- Authors
- Tronstad, Lusha
- Date of Issue
- 2013-11
- Publisher
- National Park Service
- Units
- FOLA , NGPN , NRSS
- Keywords
- Aquatic Invertebrate Monitoring, invertebrate inventory