National Park Service U.S. Department of the Interior Natural Resource Stewardship and Science Bioassessment of aquatic invertebrates along the Laramie River at Fort Laramie National Historic Site Natural Resource Technical Report NPS/NGPN/NRTR—2013/823 ON THIS PAGE Ken Brown collecting aquatic invertebrates in the Laramie River at Fort Laramie National Historic Site Photograph by: Lusha Tronstad, WYNDD, University of Wyoming ON THE COVER The Laramie River where it flows into Fort Laramie National Historic Site Photograph by: Lusha Tronstad, WYNDD, University of Wyoming Bioassessment of aquatic invertebrates along the Laramie River at Fort Laramie National Historic Site Natural Resource Technical Report NPS/NGPN/NRTR—2013/823 Lusha Tronstad Wyoming Natural Diversity Database University of Wyoming 1000 East University Avenue Laramie, Wyoming 82071 November 2013 U.S. Department of the Interior National Park Service Natural Resource Stewardship and Science Fort Collins, Colorado The National Park Service, Natural Resource Stewardship and Science office in Fort Collins, Colorado, publishes a range of reports that address natural resource topics. These reports are of interest and applicability to a broad audience in the National Park Service and others in natural resource management, including scientists, conservation and environmental constituencies, and the public. The Natural Resource Technical Report Series is used to disseminate results of scientific studies in the physical, biological, and social sciences for both the advancement of science and the achievement of the National Park Service mission. The series provides contributors with a forum for displaying comprehensive data that are often deleted from journals because of page limitations. All manuscripts in the series receive the appropriate level of peer review to ensure that the information is scientifically credible, technically accurate, appropriately written for the intended audience, and designed and published in a professional manner. This report received informal peer review by subject-matter experts who were not directly involved in the collection, analysis, or reporting of the data. Data in this report were collected and analyzed using methods based on established, peer-reviewed protocols and were analyzed and interpreted within the guidelines of the protocols. Views, statements, findings, conclusions, recommendations, and data in this report do not necessarily reflect views and policies of the National Park Service, U.S. Department of the Interior. Mention of trade names or commercial products does not constitute endorsement or recommendation for use by the U.S. Government. This report is available from m the Northern Great Plains Inventory & Monitoring Network website (http://science.nature.nps.gov/im/units/NGPN), the Natural Resource Publications Management website (http://www.nature.nps.gov/publications/nrpm/), and the WYNDD website (http://www.uwyo.edu/wyndd/reports-and-publications/). Please cite this publication as: 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. NPS 375/122848, November 2013 ii Contents Page Figures............................................................................................................................................ iv Tables .............................................................................................................................................. v Abstract .......................................................................................................................................... vi Acknowledgments......................................................................................................................... vii Introduction ..................................................................................................................................... 1 Study Area ...................................................................................................................................... 3 Methods........................................................................................................................................... 5 Results ............................................................................................................................................. 8 Discussion ..................................................................................................................................... 18 Conclusions ................................................................................................................................... 23 Literature ....................................................................................................................................... 24 Appendix A. .................................................................................................................................. 29 iii Figures Page Figure 1. Map of Fort Laramie National Historic Site showing where aquatic invertebrate samples were collected. .............................................................................................. 4 Figure 2. Trichoptera (a) were the most abundant invertebrates, followed by Diptera (b) and Ephemeroptera (c). Bold lines are median values, the lower and upper edges of the box represent the 25th and 75th percentile, and whiskers are the upper and lower limits of the data.............................................................................................................................. 9 Figure 3. Density (ind/m2) of invertebrate functional feeding groups at site 1 (green), site 2 (yellow), and site 3 (blue) in the Laramie River at Fort Laramie National Historic Site. Bold lines are median values, lower and upper edges of the boxes are the 25th and 75th percentiles, and whiskers are limits of the data.................................................. 10 Figure 4. Density (ind/m2) of invertebrate habits at site 1 (green), site 2 (yellow), and site 3 (blue) in the Laramie River at Fort Laramie National Historic Site. Bold lines are median values, lower and upper edges of the boxes are the 25th and 75th percentiles, and whiskers are the lower and upper limits of the data. .......................................... 11 iv Tables Page Table 1. Invertebrate bioassessment metrics used to compare sites at Fort Laramie National Historic Site. ..................................................................................................................... 6 Table 2. Site locations and basic water quality at each site along the Laramie River at Fort Laramie National Historic Site. ............................................................................................... 8 Table 3. Average density (ind/m2) of insects at each site along the Laramie River at Fort Laramie National Historic Site. Variance is standard error. Higher taxonomic headings (bold) show total mean densities for the group. ............................................................ 12 Table 4. Average density (ind/m2) of non-insect invertebrates at each site along the Laramie River at Fort Laramie National Historic Site. Variance is standard error. Higher taxonomic headings (bold) show total mean densities for the group. .............................. 15 Table 5. Average invertebrate bioassessment metrics for each site along the Laramie River at Fort Laramie National Historic Site. Variance is standard error. Metrics with significant site effects (ANOVA; P < 0.05) were marked with an asterisk and significant differences among sites (multiple comparison tests) were shown in the differences column. For definitions of metrics see methods. ...................................................... 16 Table 6. Selected invertebrate bioassessment metrics in the Laramie River at Fort Laramie National Historic Site compared to other rivers in parks within the Northern Great Plains Network region. The Belle Fourche River flows through Devils Tower National Monument (Tronstad, in review), the Little Missouri River flows through Theodore Roosevelt National Park (Tronstad 2013a), and the Knife River flows through Knife River Indian Villages National Historic Site (Tronstad 2013b). ........................... 19 Table 7. Metrics included in the Wyoming Stream Integrity Index for the southeastern plains, the expected trend in relation to stream impairment, the threshold values for least disturbed sites, and metrics calculated for three sites along the Laramie River at Fort Laramie National Historic Site. Metrics from the Laramie River were electronically composited to simulate field composite samples used to develop the metrics. ...................................................................................................................... 20 v Abstract 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