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Response of diatom assemblages to the disruption of the running water continuum in urban areas, and its consequences on bioassessment

Transformation of river and stream channels disrupts their natural ecological cycles and interrupts the continuum of their ecosystems. Changes in natural hydromorphological conditions transform lotic communities into those atypical of flowing waters, resulting in bioassessment procedures yielding in...

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Autores principales: Szczepocka, Ewelina, Nowicka-Krawczyk, Paulina, Olszyński, Rafał M., Żelazna-Wieczorek, Joanna
Formato: Online Artículo Texto
Lenguaje:English
Publicado: PeerJ Inc. 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8621708/
https://www.ncbi.nlm.nih.gov/pubmed/34900419
http://dx.doi.org/10.7717/peerj.12457
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author Szczepocka, Ewelina
Nowicka-Krawczyk, Paulina
Olszyński, Rafał M.
Żelazna-Wieczorek, Joanna
author_facet Szczepocka, Ewelina
Nowicka-Krawczyk, Paulina
Olszyński, Rafał M.
Żelazna-Wieczorek, Joanna
author_sort Szczepocka, Ewelina
collection PubMed
description Transformation of river and stream channels disrupts their natural ecological cycles and interrupts the continuum of their ecosystems. Changes in natural hydromorphological conditions transform lotic communities into those atypical of flowing waters, resulting in bioassessment procedures yielding incorrect results. This study shows how hydromorphological transformations of ecosystems affect the ecological status bioassessment results by disturbing diatom communities typical for rivers. Moreover, the article presents a new biological assessment procedure for urban transformed rivers including the verification of the community structure based on autecology and quantity of species. The ecological status of the ecosystem was assessed using benthic diatom assemblages and supported with results of hydrochemical analysis. The structure of the assemblages and their relationships between individual sampling sites were clarified by shade plot and multivariate data analyses. The analysis of dominant species vitality at sampling sites and their autecology gave the foundation for modification of taxa data matrix and recalculation the diatom indices. Biological assessment showed that one of the artificial ponds constructed at the stream channel was characterized by good ecological status, and its presence strongly affected the state of the downstream ecosystem following the development of a unique assemblage of diatoms that prefer oligosaprobic and oligotrophic waters. The presence of these species was also noted in the downstream sections, but most of the cells were dead. As the indicator values of these taxa are high, their presence artificially increased the ecological status of the stream, resulting in the hydrochemical assessment not being in line with the bioassessment. Therefore, a new procedure was adopted in which non-characteristic taxa for the downstream sections were excluded from analysis. This approach corrected the results of bioassessment characterizing the ecological status of the stream as poor along its entire course, with the exception of this unique pond. For hydromorphologically transformed streams and rivers with disturbed channel continuity, the correct result of an incorrect diatom-based bioassessment may be retrieved after excluding species unusual for the type of ecosystem from the studied assemblages, i.e., the species which are unable to reproduce in that area and are only carried into it by the water flow. Assessment of the ecological status of aquatic ecosystems based on biotic factors is an essential tool of aquatic ecosystems monitoring in many countries. This type of assessment requires a multifaceted approach, in particular, to identify factors that may disrupt this assessment. Standardization of biomonitoring methods is an important step in correct assessment; thus, the findings of this paper will be useful in routine biomonitoring around the world.
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spelling pubmed-86217082021-12-09 Response of diatom assemblages to the disruption of the running water continuum in urban areas, and its consequences on bioassessment Szczepocka, Ewelina Nowicka-Krawczyk, Paulina Olszyński, Rafał M. Żelazna-Wieczorek, Joanna PeerJ Ecology Transformation of river and stream channels disrupts their natural ecological cycles and interrupts the continuum of their ecosystems. Changes in natural hydromorphological conditions transform lotic communities into those atypical of flowing waters, resulting in bioassessment procedures yielding incorrect results. This study shows how hydromorphological transformations of ecosystems affect the ecological status bioassessment results by disturbing diatom communities typical for rivers. Moreover, the article presents a new biological assessment procedure for urban transformed rivers including the verification of the community structure based on autecology and quantity of species. The ecological status of the ecosystem was assessed using benthic diatom assemblages and supported with results of hydrochemical analysis. The structure of the assemblages and their relationships between individual sampling sites were clarified by shade plot and multivariate data analyses. The analysis of dominant species vitality at sampling sites and their autecology gave the foundation for modification of taxa data matrix and recalculation the diatom indices. Biological assessment showed that one of the artificial ponds constructed at the stream channel was characterized by good ecological status, and its presence strongly affected the state of the downstream ecosystem following the development of a unique assemblage of diatoms that prefer oligosaprobic and oligotrophic waters. The presence of these species was also noted in the downstream sections, but most of the cells were dead. As the indicator values of these taxa are high, their presence artificially increased the ecological status of the stream, resulting in the hydrochemical assessment not being in line with the bioassessment. Therefore, a new procedure was adopted in which non-characteristic taxa for the downstream sections were excluded from analysis. This approach corrected the results of bioassessment characterizing the ecological status of the stream as poor along its entire course, with the exception of this unique pond. For hydromorphologically transformed streams and rivers with disturbed channel continuity, the correct result of an incorrect diatom-based bioassessment may be retrieved after excluding species unusual for the type of ecosystem from the studied assemblages, i.e., the species which are unable to reproduce in that area and are only carried into it by the water flow. Assessment of the ecological status of aquatic ecosystems based on biotic factors is an essential tool of aquatic ecosystems monitoring in many countries. This type of assessment requires a multifaceted approach, in particular, to identify factors that may disrupt this assessment. Standardization of biomonitoring methods is an important step in correct assessment; thus, the findings of this paper will be useful in routine biomonitoring around the world. PeerJ Inc. 2021-11-23 /pmc/articles/PMC8621708/ /pubmed/34900419 http://dx.doi.org/10.7717/peerj.12457 Text en ©2021 Szczepocka et al. https://creativecommons.org/licenses/by/4.0/This is an open access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use, distribution, reproduction and adaptation in any medium and for any purpose provided that it is properly attributed. For attribution, the original author(s), title, publication source (PeerJ) and either DOI or URL of the article must be cited.
spellingShingle Ecology
Szczepocka, Ewelina
Nowicka-Krawczyk, Paulina
Olszyński, Rafał M.
Żelazna-Wieczorek, Joanna
Response of diatom assemblages to the disruption of the running water continuum in urban areas, and its consequences on bioassessment
title Response of diatom assemblages to the disruption of the running water continuum in urban areas, and its consequences on bioassessment
title_full Response of diatom assemblages to the disruption of the running water continuum in urban areas, and its consequences on bioassessment
title_fullStr Response of diatom assemblages to the disruption of the running water continuum in urban areas, and its consequences on bioassessment
title_full_unstemmed Response of diatom assemblages to the disruption of the running water continuum in urban areas, and its consequences on bioassessment
title_short Response of diatom assemblages to the disruption of the running water continuum in urban areas, and its consequences on bioassessment
title_sort response of diatom assemblages to the disruption of the running water continuum in urban areas, and its consequences on bioassessment
topic Ecology
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8621708/
https://www.ncbi.nlm.nih.gov/pubmed/34900419
http://dx.doi.org/10.7717/peerj.12457
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