Determining the Association Between the Structure of Stream Benthic Macroinvertebrate Communities and Agricultural Best Management Practices PDF Download
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Author: Roger Holmes (M.Sc.)
Publisher:
ISBN:
Category :
Languages : en
Pages : 174
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Book Description
Farmers have been encouraged to adopt more sustainable farming practices (BMPs) that mitigate adverse agricultural effects on the natural environment. However, the ability of BMPs to protect or restore riverine systems continues to be questioned due to limited evidence directly linking BMP use with improved ecological conditions. The exclusion of hydrological pathways in previous field studies may explain why a direct link has not yet been established. The goal of this study was to assess the association between benthic macroinvertebrate community structure and the number and location of agricultural BMPs. Macroinvertebrates and water chemistry were sampled in 30 headwater catchments in the Grand River Watershed. Catchments exhibited gradients of BMP use and location as measured by the degree of hydrologic connectedness. Stepwise ordination regressions and variance partitioning were used to determine which environmental variables (i.e., BMP metrics, water chemistry parameters, habitat characteristics, and land use variables) were associated with benthic macroinvertebrate community structure. Water chemistry parameters were negatively associated with BMP metrics suggesting BMPs were mitigating losses of nutrients and sediments. However, BMP abundance and location explained minimal variation in benthic macroinvertebrate structure within the 30 sampled catchments. The absence of a strong association between BMPs and benthic macroinvertebrates may indicate a need for greater numbers and targeted siting of BMPS to improve water quality beyond a threshold point that would allow recolonization of intolerant invertebrate taxa. Focusing of conservation goals on ecological conditions and the promotion of BMPs that enhance in-stream habitat may also be required.
Author: Roger Holmes (M.Sc.)
Publisher:
ISBN:
Category :
Languages : en
Pages : 174
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Book Description
Farmers have been encouraged to adopt more sustainable farming practices (BMPs) that mitigate adverse agricultural effects on the natural environment. However, the ability of BMPs to protect or restore riverine systems continues to be questioned due to limited evidence directly linking BMP use with improved ecological conditions. The exclusion of hydrological pathways in previous field studies may explain why a direct link has not yet been established. The goal of this study was to assess the association between benthic macroinvertebrate community structure and the number and location of agricultural BMPs. Macroinvertebrates and water chemistry were sampled in 30 headwater catchments in the Grand River Watershed. Catchments exhibited gradients of BMP use and location as measured by the degree of hydrologic connectedness. Stepwise ordination regressions and variance partitioning were used to determine which environmental variables (i.e., BMP metrics, water chemistry parameters, habitat characteristics, and land use variables) were associated with benthic macroinvertebrate community structure. Water chemistry parameters were negatively associated with BMP metrics suggesting BMPs were mitigating losses of nutrients and sediments. However, BMP abundance and location explained minimal variation in benthic macroinvertebrate structure within the 30 sampled catchments. The absence of a strong association between BMPs and benthic macroinvertebrates may indicate a need for greater numbers and targeted siting of BMPS to improve water quality beyond a threshold point that would allow recolonization of intolerant invertebrate taxa. Focusing of conservation goals on ecological conditions and the promotion of BMPs that enhance in-stream habitat may also be required.
Author: Andrew F. Burgess
Publisher:
ISBN:
Category : Agricultural pollution
Languages : en
Pages : 250
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Book Description
Author: Raj Kiran Parmar
Publisher:
ISBN:
Category : Aquatic invertebrates
Languages : en
Pages : 124
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Book Description
Land cover change strongly affects biodiversity in stream ecosystems, with several studies demonstrating the negative impacts of agricultural and urban expansion on local community richness. However, little is known of the effects of land cover on the variation among sets of local communities in stream networks, as well as the drivers of community variation in these systems. Using the metacommunity framework, this study takes a multi-scale approach to understand how macroinvertebrate communities are assembled across three catchment land cover types; native forest, agricultural and urban. Specifically, the aims of this study are to assess; (1) how stream network land cover influences alpha and beta diversity of macroinvertebrate communities and, (2) the relative role of local environmental conditions and spatial dispersal variables in structuring these communities. Benthic macroinvertebrate samples and local in-stream and riparian environmental variables were collected at 20 sampling sites in each of the six study stream networks in Auckland. Spatial distance proxies of macroinvertebrate dispersal in stream networks were calculated using geospatial techniques. Community alpha and beta diversity, environmental and distance variables were analysed using multivariate statistical techniques. Comparisons showed reference forest and impacted (agricultural and urban) networks supported distinct communities, with lower alpha diversity in the impacted stream networks. Unexpectedly, beta diversity in the impacted networks was greater than, or equal to the reference stream networks, with community dissimilarity almost entirely driven by species turnover. Overall, irrespective of land cover, macroinvertebrate communities were largely structured by local environmental conditions. Benthic substrate and the presence and composition of riparian vegetation were the most significant local environmental variables influencing community composition. Spatial dispersal limitation variables had a small, but significant, effect on inter-site community dissimilarity and overall community structure in each catchment. Network distance between local communities explained the greatest variation in community dissimilarity of the three distance types. This study identified potential drivers of macroinvertebrate community variation in Auckland streams, specifically highlighting the relative role of local environmental and spatial dispersal processes. The results of this study have relevance for biomonitoring and state of environment reporting of Auckland’s freshwater systems, as well as future stream rehabilitation projects.
Author: Jamie Bartram
Publisher: CRC Press
ISBN: 1000101606
Category : Technology & Engineering
Languages : en
Pages : 396
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Book Description
Water quality monitoring is an essential tool in the management of water resources and this book comprehensively covers the entire monitoring operation. This important text is the outcome of a collborative programme of activity between UNEP and WHO with inputs from WMO and UNESCO and draws on the international standards of the International Organization of Standardization.
Author: National Agricultural Library (U.S.)
Publisher:
ISBN:
Category : Agricultural conservation
Languages : en
Pages : 380
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Book Description
"The bibliography is a guide to recent scientific literature covering effects of agricultural conservation practices on fish and wildlife. The citations listed here provide information on how conservation programs and practices designed to improve fish and wildlife habitat, as well as those intended for other purposes (e.g., water quality improvement), affect various aquatic and terrestrial fauna"--Abstract.
Author: Jason Saltman
Publisher:
ISBN:
Category : Land use
Languages : en
Pages : 63
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Book Description
In this study, I examined relationships between land-use patterns and macroinvertebrate communities in 45 first through fourth-order stream reaches in four subwatersheds within a New England watershed. Land-use patterns were quantified in GIS at three spatial scales to determine the effect of scale on the strength of relationships between instream biological conditions and adjacent land-use conditions. A GIS was used to quantify forest, agricultural, and developed land use at three spatial scales, including the entire upstream catchment area and two sub-corridors. Macroinvertebrate communities were analyzed using a multimetric approach and a multivariate approach to relate community composition to land-use variables measured at each spatial scale. Among community metrics, richness, EPT richness, percent affinity, and total metric scores were significantly correlated with quantified land-use variables, including percent forest, percent agriculture, percent developed, and percent agriculture + developed at the upstream catchment scale. Land-use variables also showed significant correlations with community composition as indicated by ordination axes resulting from multivariate analysis. Results of the approaches were in general agreement with each other, each indicating that relationships between instream benthic conditions and adjacent land use were strongest at the entire-upstream-catchment scale. These results suggest that conditions and processes occurring at this scale appear to be more influential than are localized adjacent land-use conditions in shaping community composition and in-stream biological conditions.
Author: Leonard Sandin
Publisher:
ISBN:
Category : Benthos
Languages : en
Pages : 180
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Book Description
Author: Hector R. Santiago
Publisher:
ISBN:
Category : Benthos
Languages : en
Pages : 234
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Book Description
Abstract: Although the notion that streams are influenced by the character of their landscape at multiple spatial scales is not new, the relative degree to which local versus regional factors affect ecological function in streams is not fully understood, and can be different between geographically proximate watersheds. Anthropogenic disturbances to the landscape such as agricultural practices can be detrimental to stream ecosystems. This study examined the influences of local habitat and riparian corridor condition compared to regional landscape influences on benthic macroinvertebrate assemblages in a Midwestern agroecosytem. Twenty-four reaches in the North Fork and Upper Fork sub-basins of the Sugar Creek watershed, Wayne County, Ohio were sampled to better understand how different habitat and landscape factors affect the structure of macroinvertebrate assemblages in these impacted headwater streams. A total of 72,529 macroinvertebrates representing 79 families in 22 orders were collected during Autumn of 2005 and Spring 2006 to compare assemblage structure between watersheds and across seasons. Family richness, evenness, and diversity showed no difference attributable to watershed, while evenness and diversity exhibited seasonal differences. Chironomid abundance seemed to account for the seasonal change. Percent Ephemeroptera, Plecoptera, and Trichoptera (%EPT) was significantly influenced by watershed and season with the North Fork watershed exhibiting a higher abundance of these pollution tolerant and habitat sensitive taxa than the Upper Fork at all sample sites. A Geographic information system (GIS) was used to delineate sample watersheds and analyze landscape character. Proportion (%) of low Intensity residential, high intensity residential, industrial/commercial, deciduous forest, evergreen forest, mixed forest, row crop, pasture/hay, wooded wetland and herbaceous wetland were calculated per hydrologic unit. The dominant land uses in both study watersheds were crop, pasture, deciduous forest, and low intensity residential. The North Fork exhibited a significantly higher proportion of pasture and deciduous forest land types than the Upper Fork, which was dominated by row crops, then pasture and forest respectively. North Fork had almost twice the amount of deciduous forest as did the Upper Fork. Canonical correspondence analysis (CCA) was used to assess the macroinvertebrate family-environment relationship and variance partitioning determined the degree of influence of 8 local and 8 regional environmental factors on invertebrate assemblage structure in each study basin. Local habitat factors explained 25.8% of the total variance while regional landscape factors explained 23.6% of the total variance with 2.7% of the variability shared by both. Upper Fork sites were generally scattered along a silt/muck to cobble habitat gradient, while North Fork sites were arranged along a pasture-forest to rowcrop landscape gradient. The higher proportion of pasture and deciduous forest in the North Fork may explain the greater distribution of EPT taxa found in the watershed, while the greater proportion of crops and smaller proportion of forest in the Upper Fork may explain the greater influence of fine substrates in the watershed. Other environmental factors including glacial geology and groundwater influence may have also contributed to these differences by introducing coarser substrates and cooler, stream temperatures.
Author: Sean D. Sipple
Publisher:
ISBN:
Category :
Languages : en
Pages : 213
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Book Description
Headwater streams comprise the majority of the stream network, providing important ecological functions to the downstream network. Although we are beginning to understand how network structure may influence fish, our understanding of how it influences benthic macroinvertebrate dispersal and population connectivity is limited. We also know little about how these patterns and processes may be disrupted as a result of human-driven landscape change such as stream barriers to movement and creation of artificial habitats such as stormwater and farm ponds. In this study, I investigated the effect of stream network position, stream size, and local habitat on benthic macroinvertebrates, and determined to what degree road crossings and impoundments may be degrading benthic macroinvertebrate and fish communities in headwater streams. These mechanisms were explored using Maryland Department of Natural Resources, (MDNR) Maryland Biological Stream Survey (MBSS) benthic macroinvertebrate, fish, and environmental data from first-order streams in the Piedmont region of Maryland. Using an Information Theoretic Approach (ITA), models were developed based on the hypothesized relationships between benthic macroinvertebrate and fish community structure and several network and anthropogenic impact variables. Based on my results, aquatic community structure was dependent on local habitat conditions and stream network structure. Both assemblages responded negatively to roads, which may suggest an isolation effect. These results also suggest that impoundments are acting as sources for benthic macroinvertebrates and fish, including non-native species.
Author: Elizabeth Ellen Risley
Publisher:
ISBN:
Category : Geomorphology
Languages : en
Pages : 166
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Book Description
Abstract: In-stream habitat structure and water chemistry have significant influence on the structure and composition of stream macroinvertebrate assemblages. Habitat at this local scale can be significantly affected by the geomorphology of a stream or region. Both in-stream habitat and geomorphology are, in turn, influenced by other factors operating at the landscape scale (e.g., land use, connectivity of habitat patches, etc.). It is unclear which of these three scales of habitat has the greatest influence over lotic assemblage structure. Anthropogenic disturbance to a stream ecosystem can occur at all three scales of habitat, and is particularly common in predominantly agricultural systems. The Sugar Creek watershed in northeastern Ohio represents several different types of anthropogenic disturbance, including dairy farming, crop production, urbanization, and industrialization. The South and Middle Forks of the Sugar Creek watershed, dominated by agriculture and a mix of agriculture and industry, respectively, were sampled in early summer 2005 for habitat and macroinvertebrates. Richness, evenness, diversity, familylevel biotic index, percent Diptera Chironomidae, and the number of macroinvertebrates were all similar across the drainages. The percent Ephemeroptera, Plecoptera, and Trichoptera was significantly larger in the Middle Fork than in the South Fork. There were no significant differences in habitat or macroinvertebrate assemblages between the two drainages overall. In-stream habitat structure and water chemistry explained 58.8% of the variation between sites among macroinvertebrate taxa. Geomorphology explained 10.4% and land use 9.4% of the variation. Shared variances between different scales of habitat did not explain substantial amounts of variation among macroinvertebrate taxa. These results have, however, identified several sites in the South Fork with good potential for Best Management Practice implementation and several sites in the Middle Fork for preservation.
