ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    ISSN: 1573-5117
    Keywords: index of biotic integrity ; stream ; fish ; erosion ; sediment ; physical habitat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Indices of biotic integrity (1131) were computed for two annual fish collections from 27 locations along the bluffline bordering the Mississippi River alluvial plain in northwestern Mississippi. Study sites exhibited varying degrees of physical habitat degradation due to accelerated channel erosion. Objectives of index application were to quantify existing environmental quality and to test the IBI as a tool for relating fish population characteristics to physical degradation. Physical habitat data were collected concurrently with fish at all sites, and physical habitat descriptors were compared with the IBI scores and component metrics. Three to 23 fish species were captured from each site, and species richness explained 64–70% of the variance in IBI scores. Fish collections were dominated by insectivores tolerant of habitat and water quality degradation. Suckers and piscivores were relatively uncommon. The IBI scores were generally not reflective of physical habitat conditions. Variation in IBI scores was indicative of only the grossest differences in physical habitat quality. Weak relationships between physical habitat quality and IBI scores may have been due to large temporal variations in biotic integrity typical of degraded habitats. Alternatively, water quality degradation, which we did not measure, may have confounded relationships between physical habitat and fish metrics. Regional application of the IBI as a habitat assessment tool in landscapes with widespread physical degradation must overcome lack of suitable reference sites, large temporal variation in IBI scores, and small numbers of fish per collection, leading to lower confidence levels for IBI scores. The scarcity of lightly impacted sites may hinder detection of biotic integrity response along gradients of physical habitat quality.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    ISSN: 1573-5117
    Keywords: stream restoration ; fish ; erosion ; sediment ; physical habitat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Channel incision has major impacts on stream corridor ecosystems, leading to reduced spatial habitat heterogeneity, greater temporal instability, less stream-floodplain interaction, and shifts in fish community structure. Most literature dealing with channel incision examines physical processes and erosion control. A study of incised warmwater stream rehabilitation was conducted to develop and demonstrate techniques that would be economically feasible for integration with more orthodox, extensively employed watershed stabilization techniques (e.g., structural bank protection, grade control structures, small reservoirs, and land treatment). One-km reaches of each of five northwest Mississippi streams with contributing drainage areas between 16 and 205 km2 were selected for a 5-year study. During the study two reaches were modified by adding woody vegetation and stone structure to rehabilitate habitats degraded by erosion and channelization. The other three reaches provided reference data, as two of them were degraded but not rehabilitated, and the third was only lightly degraded. Rehabilitation approaches were guided by conceptual models of incised channel evolution and fish community structure in small warmwater streams. These models indicated that rehabilitation efforts should focus on aggradational reaches in the downstream portions of incising watersheds, and that ecological status could be improved by inducing formation and maintenance of stable pool habitats. Fish and physical habitat attributes were sampled from each stream during the Spring and Fall for 5 years, and thalweg and cross-section surveys were performed twice during the same period. Rehabilitation increased pool habitat availability, and made the treated sites physically more similar to the lightly degraded reference site. Fish communities generally responded as suggested by the aforementioned conceptual model of fish community structure. Species composition shifted away from small colonists (principally cyprinids and small centrarchids) toward larger centrarchids, catostomids, and ictalurids. Fish density and species richness increased at one rehabilitated site but remained stable at the other, suggesting that the sites occupied different initial states and endpoints within the conceptual model, and differed in their accessibility to sources of colonizing organisms. These experiments suggest that major gains in stream ecosystem rehabilitation can be made through relatively modest but well-designed efforts to modify degraded physical habitats.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...