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13. Tributary mitigates river discontinuity by dam depending on the distance from dam to the tributary confluence.

Author

Katano, Izumi, Doi, Hideyuki, Negishi, Junjiro N., Minagawa, Tomoko, and Kayaba, Yuichi

Subjects
DAMS, PRINCIPAL components analysis, SEDIMENT transport, RIVER channels, WATER quality, QUALITY factor
Abstract

River ecosystems host a continuum of various discontinuities, such as dams and tributary inflows, which shape the habitats of aquatic organisms; this makes it important to evaluate the interactions among discontinuities and effects of a single discontinuity point. Herein, we focused on tributaries in dammed rivers to elucidate a manner to mediate discontinuities and hypothesized that the effects of the tributary inflow on the downstream river were mediated by the (1) distance between the dam and tributary inflow, (2) size ratio between the dam and tributary, and (3) ability of the tributary to transport fine sediments, such as sand and gravel. We conducted field investigations to measure 24 environmental factors, including the water column, riverbed, and river topography, along eight dammed rivers to test the three hypotheses. Only five factors differed significantly between the upstream and downstream sites of the tributary confluence, whereas 12 factors differed significantly between the tributary and mainstem. We also classified the variation pattern using principal component analysis (PCA). The correlation between each PCA axis and environmental factors suggests that the modifications of the water quality factors by tributary inflow were significantly correlated with the distance between the dam and the tributary inflow, and that the flux of various riverbed factors, that is, was significantly correlated with the ability to resupply of fine riverbed sediments by the tributary. Overall, tributary‐inflow downstream of a dam has the potential to be applicable in environmental restoration, especially in terms of resupplying fine sediment. [ABSTRACT FROM AUTHOR]

Published
2024
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14. Applicability of environmental DNA metabarcoding for the hyporheic zone of a stream bed

Author

Tanaka, Aki, Katano, Izumi, Doi, Hideyuki, Iguchi, Mami, Koike, Shohei, Tanaka, Aki, Katano, Izumi, Doi, Hideyuki, Iguchi, Mami, and Koike, Shohei

Abstract

Hyporheic zones play a crucial role in ecological processes primarily orchestrated by hyporheic organisms, known as hyporheos. Our understanding of riverine biodiversity, encompassing hyporheic zones, remains limited. Therefore, the development of a method for the facile and accurate detection of hyporheic communities is imperative. Thus, we evaluated the applicability of environmental DNA (eDNA) metabarcoding surveys in the hyporheic zone in a small stream in Japan. We conducted simultaneous direct sampling and eDNA surveys at two different locations (head and tail of a rapid and a bar) and during two different seasons (less and more disturbed periods). Subsequently, we compared the outcomes of these sampling methods, locations, and seasons. Through eDNA metabarcoding targeting the cytochrome-c oxidase subunit I (COI) regions, we successfully identified a diverse array of hyporheic and benthic taxa in all samples. Remarkably, the performance of eDNA metabarcoding was comparable to the identification of directly sampled benthos and hyporheos. We observed a 62%–78% concordance between direct sampling and eDNA metabarcoding. Notably, eDNA metabarcoding revealed a higher number of hyporheic taxa compared to direct sampling. Moreover, the relative detectability of hyporheos by eDNA metabarcoding differed between the seasons, unlike direct sampling. Our findings underscore the importance of conducting both eDNA surveys and direct sampling to comprehensively assess the composition of the stream community while accounting for seasonal variations. This study demonstrates the utility of eDNA metabarcoding as a non-destructive approach for investigating the hyporheic zone, enabling a more effective assessment of riverine biodiversity.

Published
2023

32. Effects of sampling seasons and locations on fish environmental DNA metabarcoding in dam reservoirs

Author

Hayami, Kana, primary, Sakata, Masayuki K., additional, Inagawa, Takashi, additional, Okitsu, Jiro, additional, Katano, Izumi, additional, Doi, Hideyuki, additional, Nakai, Katsuki, additional, Ichiyanagi, Hidetaka, additional, Gotoh, Ryo O., additional, Miya, Masaki, additional, Sato, Hirotoshi, additional, Yamanaka, Hiroki, additional, and Minamoto, Toshifumi, additional

Published
2020
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34. Appendix, Supplementary Tables, and Supplementary Figures from A shady phytoplankton paradox: When phytoplankton increases under low light from A shady phytoplankton paradox: when phytoplankton increases under low light

Author

Yamamichi, Masato, Kazama, Takehiro, Tokita, Kotaro, Katano, Izumi, Doi, Hideyuki, Yoshida, Takehito, Hairston, Nelson G., and Jotaro Urabe

Abstract

1 appendix, 2 supplementary tables, & 12 supplementary figures. Appendix S1: Chemical analyses and enumeration of plankton. Table S1: The number of individuals and total wet weight of introduced largemouth bass. Table S2: Parameter descriptions and default values of the model. Figure S1: Dissolved oxygen (DO) in the ponds. Figure S2: The relationship between submersed macrophyte coverage and biomass. Figure S3: Relationships between light attenuation coefficients and phytoplankton. Figure S4: Relationships between chlorophyll a and total phosphorus, total nitrogen, zooplankton biomass, and zooplankton body length. Figure S5: Relationships between total biovolume of phytoplankton and chlorophyll a. Figure S6: Bifurcation plots with parameters for nitrogen. Figure S7: Bifurcation plots of nutrients in the pelagic habitat. Figure S8: Analyses as in Figs. 2 and 3 based on phytoplankton biomass. Figure S9: Analyses as in Figs. 2 and 3 based on seston carbon. Figure S10: Phytoplankton biomass composition changes during the experiment. Figure S11: Principle component analysis of phytoplankton biomass dynamics. Figure S12: Relationships between zooplankton body size and phytoplankton abundance.

Published
2018
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36. Supplementary material 1 from: Matsuoka S, Sugiyama Y, Sato H, Katano I, Harada K, Doi H (2019) Spatial structure of fungal DNA assemblages revealed with eDNA metabarcoding in a forest river network in western Japan. Metabarcoding and Metagenomics 3: e36335. https://doi.org/10.3897/mbmg.3.36335

Author

Matsuoka, Shunsuke, primary, Sugiyama, Yoriko, additional, Sato, Hirotoshi, additional, Katano, Izumi, additional, Harada, Ken, additional, and Doi, Hideyuki, additional

Published
2019
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38. Supplementary material 2 from: Matsuoka S, Sugiyama Y, Sato H, Katano I, Harada K, Doi H (2019) Spatial structure of fungal DNA assemblages revealed with eDNA metabarcoding in a forest river network in western Japan. Metabarcoding and Metagenomics 3: e36335. https://doi.org/10.3897/mbmg.3.36335

Author

Matsuoka, Shunsuke, primary, Sugiyama, Yoriko, additional, Sato, Hirotoshi, additional, Katano, Izumi, additional, Harada, Ken, additional, and Doi, Hideyuki, additional

Published
2019
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42. Fig. S1 Abiotic factors (water temperature, electric conductivity (EC), and precipitation) at each survey station in the Shigo-gawa stream during downstream surveys. Precipitation was observed at Nara Meteorological Observatory. Table S1. Environmental variables (mean ± 1 SD) of each sampling site. The values in parentheses are sample sizes. from Distribution and drift dispersal dynamics of a caddisfly grazer in response to resource abundance and its ontogeny

Author

Katano, Izumi, Hiromune Mitsuhashi, Doi, Hideyuki, Isobe, Yu, and Oishi, Tadashi

Subjects
animal structures, fungi
Abstract

Stream grazers have a major impact on food web structure and the productivity of stream ecosystems; however, studies on the longitudinal (upstream versus downstream) and temporal changes in their drift dynamics and resulting distributions remain limited. Here, we investigated the longitudinal and temporal distributions and drift propensity of a trichopteran grazer, the caddisfly, Micrasema quadriloba, during its life cycle in a Japanese stream. The distribution of larvae significantly shifted downstream during the fifth instar larval stage during late winter; with periphyton abundance (i.e. their food source) showing similar shifts downstream. Therefore, our results show that the drift dispersal the caddisfly occurs in response to decline in available food resources (i.e. food-resource scarcity) and an increase in food requirements by growing individuals. Furthermore, our results show that this observed longitudinal shift in larval distribution varies through their life cycle, because the drift dispersal of fifth instar larvae was greater than that of immature larvae. The correlation between periphyton abundance and drift propensity of fourth instar larvae was not statistically significant, whereas that of fifth instar larvae was significantly negative. In conclusion, we detected an ontogenetic shift in drift propensity, which might explain the longitudinal and temporal distributions of this species.

Published
2017
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