Author: Ashley K. RawhouserPublisher:
ISBN:
Category : Benthos
Languages : en
Pages : 144
Book Description
Detecting Changes in the Benthic Invertebrate Community Structure of Minimally Impacted Streams in the North Cascades of Washington State
Author: Ashley K. RawhouserPublisher:
ISBN:
Category : Benthos
Languages : en
Pages : 144
Book Description
Ross Lake National Recreation Area (N.R.A.), General Management Plan
Author: Seasonal Changes in a Benthic Macroinvertebrate Community of a North Cascades Mountain Stream
Author: Amy Bruenderman HillPublisher:
ISBN:
Category : Benthos
Languages : en
Pages : 122
Book Description
Cold, Snowmelt Streams Contribute to Macro-invertebrate Community Differences in Washington State
Author: Laura LivingstonPublisher:
ISBN:
Category : Freshwater invertebrates
Languages : en
Pages :
Book Description
The Effects of Instream Structures on Benthic Macroinvertebrates and Salmonid Habitat in Cee Cee Ah Creek of Pend Oreille County, Washington
Author: Scott JungblomPublisher:
ISBN:
Category : Aquatic invertebrate populations
Languages : en
Pages : 202
Book Description
"Past stream habitat restoration has been focused primarily on increasing specific fish populations with little knowledge of how these habitat manipulations affect the benthic macroinvertebrate community. This study focuses on assessing the immediate effects of instream habitat restoration structures on the benthic macroinvertebrate community and its environment. Physical measurements, water quality measurements, benthic invertebrate and substrate composition samples were taken at three experimental structure locations and one upstream control site twice before structure placement in June and July 1998 and twice after structure placement (October and November 1998). Six benthic samples were taken at each site on each sample date. Three samples each were taken five meters above and below the structure site, sampling a ten-meter zone of impact for each structure. The Kalispel Natural Resource Department built a series of salmonid stream habitat restoration structures in Cee Cee Ah Creek of Pend Oreille Co. Washington in August of 1998. Experimental site 1 received a modified single log weir or channel constrictor, site 2 received a K-dam and site 3 received an upstream-V weir. Comparisons were made between data collected at each site before structure placement vs. after and between each experimental site vs. the upstream control site. All sites shared similar physical and water quality data within each sample date except for slight differences in stream width, embeddedness, and discharge, which changed seasonally. Cobble dominated the system with a high percentage of gravel substrate present at site 3. Structure construction resulted in an increase in stream width and depth at each site above and/or below each structure. There was no significant difference in benthic density or community metric analysis between upstream and downstream samples at any site throughout the study. Therefor upstream and downstream samples were combined to assess each structure's complete ten-meter zone of impact. The upstream control site density did not change significantly throughout the study. However, the density of each experimental site (site 1, site 2, and site 3) and the combined experimental sites (site 1+2+3) did increase significantly in post structure samples (October and November combined). There was no significant difference in the density of the control site and experimental sites one or three either before or after structure placement. However, the density at site 2 (K-Dam) and at the combined experimental sites was significantly higher than the control site after structure placement (October and November combined). Community composition did not change significantly throughout the study at any site and there was no difference between the control site and any experimental site before or after structure placement. The total number of families present during the study was 60, dominated by Chironomidae at site 1 and alternated between Chironomidae and Heptageniidae at the control site, and experimental sites 2 and 3. While the number of feeding guild taxa did not change significantly at any site during the study, the percent shredder composition increased at all three structure sites for both post-structure sample dates. The upstream control did not show a similar trend. Analysis of each sample's volumetric substrate composition in relation to its invertebrate metrics values showed significant differences in metric values corresponding to certain substrate compositions for all the metrics tested except Percent Dominant Family. Samples with reduced small, medium, large and combined gravel compositions and increased cobble + boulder concentration showed an increase in water quality for the metrics: Density, Total Number of Taxa, EPT Index, and the Shannon-Weiner diversity index. However samples with the above substrate compositions showed a decrease in water quality for the metrics: Scraper/Collector ratio, percent EPT, EPT/C ratio and FBI score. This study shows that instream habitat restoration structures significantly increased local macroinvertebrate density and did not jeopardize community diversity or composition. By using instream structures that create specific substrate class compositions habitat managers may be able to enhance problem macroinvertebrate community metrics found in initial assessments. While the scope of this study was restricted to short-term effects on a specific habitat, these results clearly identified the benefits of instream structures as well as the need for future long-term studies to include pre-restoration sampling at control or reference sites"--Document.
Impacts from Water-Level Regulation on Benthic Macroinvertebrate Community Structure in Namakan Reservoir and Rainy Lake
Author: Daniel C. McewenPublisher: CreateSpace
ISBN: 9781492805311
Category : Nature
Languages : en
Pages : 100
Book Description
The authors investigated how changing the magnitude and timing of water release in a regulated reservoir impacted macrobenthic invertebrates communities within Voyageurs National Park (VOYA), Minnesota with a before-after control-impact approach, using both multi- and univariate response measures to simultaneously compare impacts on macroinvertebrates across both time and treatment.
The Effect of the Patch Mosaic on Community Structure of Benthic Invertebrates in a North Carolina Piedmont Stream
Author: Sarah Jill Gwennette KalhokPublisher:
ISBN:
Category : Freshwater ecology
Languages : en
Pages : 82
Book Description
The Relationships Between Headwater Stream Macroinvertebrate Communities and Summer Low-flow Events in a Temperate Rain Forest
Author: Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
Using a forested headwater stream system as a model, the effects of inter-annual variation in summer discharge regimes on aquatic insect communities were investigated. More specifically, the benthic invertebrate community response to the intensity, minimum discharges, frequency, duration and abruptness of summer low-flow events were examined. We hypothesized that intensification of summer low-flow events, both in duration and magnitude, have some negative impacts on benthic macroinvertebrate communities in riffles. Examples of negative impacts include reduction in their abundance and/or biodiversity. First, the abundance and functional trait data of the benthic macroinvertebrates in the three streams in the Malcolm Knapp Research Forest, British Columbia, Canada, were analyzed with respect to the low-flow events. Second, population models were built to simulate the potential responses of lotic aquatic insect communities to future climate change scenarios that differ in the rate of intensifications in extreme flow events: a low-flow event scenario within the current range versus 10% increase in intensity. The summer low-flow events were found to have a significant relationship with benthic macroinvertebrate communities through three-table ordinations of the empirical data. The community structure was correlated with a major ocean-atmosphere regime shift (Pacific Decadal Oscillation). The intensity and duration of low-flow events explained the observed shift in community structure favouring r-selected traits (e.g. short life cycle, high reproduction rate). The two low-flow severity scenarios showed the significant differential impacts on the aquatic insect community structures when individual populations were modeled according to their traits. Aquatic insects could be separated into three groups according to their sensitivities, measured by extinction rates, toward the two scenarios.
The Detection of Change in Benthic Invertebrate Communities with Surber and Modified Plate Samplers
Author: John R. WestPublisher:
ISBN:
Category : Freshwater invertebrates
Languages : en
Pages : 130
Book Description
Discontinuities in Stream Networks
Author: Melissa BrochuPublisher:
ISBN:
Category :
Languages : en
Pages : 172
Book Description
The network composition hypothesis (NCH) suggests that i) large confluence symmetry ratios (drainage area of the tributary relative to the mainstem) and ii) landscape differences (differences in landscape characteristics between the mainstem and tributary drainages) lead to greater ecological changes below confluences. As a test of the NCH, 34 confluences were sampled in southern Ontario to examine the effects of these two factors on benthic invertebrate communities to infer the degree of ecological change at confluences. Given the typology of streams surveyed, there was subtle evidence that benthic invertebrate communities below confluences changed as a function of confluence symmetry ratio and landscape differences. This indicates that abrupt changes in stream networks are not as common as theory may suggest. Further support for the network composition hypothesis may be found by examining a wider range of stream types and examining single-species responses. Keywords: tributary, landscape characteristics, benthic invertebrates, community similarity, stream networks.