The Effects of Mine Drainage on the Macrobenthic Insect Community of Blue Creek, Spokane Reservation, WA

Download or read book The Effects of Mine Drainage on the Macrobenthic Insect Community of Blue Creek, Spokane Reservation, WA written by Robert W. Plotnikoff and published by . This book was released on 1988 with total page 388 pages. Available in PDF, EPUB and Kindle. Book excerpt: "The benthic macroinvertebrate community of Blue Creek was examined in terms of density, diversity, and similarity at: (1) two stations (stations 1 and 2), located upstream from a drainage tributary carrying effluent from the Midnite uranium mine (pre- impact zone); (2) two stations (stations 3 and 4) located immediately downstream from the mine drainage tributary (impact zone); and (3) two stations (stations 5 and 6) located further downstream, below the confluence of Oyachen Creek (recovery zone). Benthic macroinvertebrate samples collected in the impact zone showed significant differences in density and diversity from samples taken in the pre-impact zone. Benthic macroinvertebrate mean density declined from 6,317 organisms/m2 in the pre-impact zone to 2,581 organisms/m2 in the impact zone. Densities were significantly different between pre-impact zone and impact zone stations (Mann-Whitney U test, p>̲ .05). Benthic macroinvertebrate diversity declined from 3.30 in the pre-impact zone to 2.80 in the impact zone which also showed significant differences (p>̲ .05). The community structure in the impact and recovery zone stations was less diverse than in upstream pre-impact zone stations. Impact zone stations were represented by fewer functional groups. Benthic macroinvertebrates collected in the impact zone of Blue Creek also showed functional differences from samples taken further upstream (pre-impact zone). Benthic invertebrates at stations 3, 4 and 5 consisted primarily of organisms representing the shredder and collector functional groups. Populations of scraper and gatherer functional groups were predominant in upstream pre- impact zone sample stations 1 and 2. Greater representation of individuals known to use autochthonous food sources (food production from within the stream, e.g. periphyton) were found at stations 1 and 2. Invertebrate populations in the impact zone were characterized by organisms which primarily consumed organic material originating from allochthonous food sources (food input from terrestrial sources, e.g., leaf litter)"--Document.