Effects of a ‘natural’ flood event on the riparian ecosystem of a regulated large-river system: the 2011 flood on the Missouri River, USA

Ecohydrology ◽  
2015 ◽  
Vol 8 (5) ◽  
pp. 812-824 ◽  
Author(s):  
Mark D. Dixon ◽  
Christopher J. Boever ◽  
Victoria L. Danzeisen ◽  
Christopher L. Merkord ◽  
Eszter C. Munes ◽  
...  
2013 ◽  
Vol 4 (1) ◽  
pp. 41-52 ◽  
Author(s):  
William E. French ◽  
Brian D. S. Graeb ◽  
Katie N. Bertrand ◽  
Steven R. Chipps ◽  
Robert A. Klumb

Abstract This study compared patterns of δ15N and δ13C enrichment of pallid sturgeon Scaphirhynchus albus and shovelnose sturgeon S. platorynchus in the Missouri River, United States, to infer their trophic position in a large river system. We examined enrichment and energy flow for pallid sturgeon in three segments of the Missouri River (Montana/North Dakota, Nebraska/South Dakota, and Nebraska/Iowa) and made comparisons between species in the two downstream segments (Nebraska/South Dakota and Nebraska/Iowa). Patterns in isotopic composition for pallid sturgeon were consistent with gut content analyses indicating an ontogenetic diet shift from invertebrates to fish prey at sizes of >500-mm fork length (FL) in all three segments of the Missouri River. Isotopic patterns revealed shovelnose sturgeon did not experience an ontogenetic shift in diet and used similar prey resources as small (<500-mm FL) pallid sturgeon in the two downstream segments. We found stable isotope analysis to be an effective tool for evaluating the trophic position of sturgeons within a large river food web.


2014 ◽  
Vol 31 (3) ◽  
pp. 335-349 ◽  
Author(s):  
C. Soulsby ◽  
C. Birkel ◽  
J. Geris ◽  
D. Tetzlaff

Author(s):  
Hae-Jin Lee ◽  
Hae-Kyung Park ◽  
Se-Uk Cheon

Flow regulation is one of the most common anthropogenic factors affecting rivers worldwide. In Korea, 16 weirs were constructed along four major rivers from 2009 to 2012. This study aimed to elucidate initial changes in physical, chemical, and biological variables after the construction of consecutive weirs on the Nakdong River, a major large river system. Water quality variables and phytoplankton cell densities were investigated at eight representative sites and compared with the data recorded before the weir construction. There were spatial and temporal changes in the hydraulic retention time (HRT), total phosphorus (TP), and chlorophyll a concentrations among the eight weir sections. HRT increased after the weir construction, while TP and chlorophyll a tended to decrease from the middle to lower section of the Nakdong River. Furthermore, differences were observed in the phytoplankton community composition between 2006–2007 and 2013. There was a marginal decrease in the duration of centric diatom (Stephanodiscus hantzschii) blooms after weir construction. However, Microcystis aeruginosa proliferated more extensively during summer and autumn than it did before the weir construction. Our results suggest that changes in hydrological factors, in response to consecutive weir construction, may contribute to greater physical, chemical, and ecological variability.


2018 ◽  
Vol 93 (6) ◽  
pp. 1107-1112 ◽  
Author(s):  
Nicolas Guillerault ◽  
Géraldine Loot ◽  
Simon Blanchet ◽  
Frederic Santoul

2019 ◽  
Vol 51 ◽  
pp. 101707 ◽  
Author(s):  
Bingfen Cheng ◽  
Rui Xia ◽  
Yuan Zhang ◽  
Zhongwen Yang ◽  
Sheng Hu ◽  
...  

2011 ◽  
Vol 27 (2) ◽  
pp. 282-290 ◽  
Author(s):  
M. L. Wildhaber ◽  
S. H. Holan ◽  
J. L. Bryan ◽  
D. W. Gladish ◽  
M. Ellersieck

<em>Abstract.</em>—The Virgin–Moapa River system supports nine native fish species or subspecies, of which five are endemic. Woundfin <em>Plagopterus argentissimus </em>and Virgin River chub <em>Gila seminuda </em>are endemic to the main-stem Virgin River, whereas cooler and clearer tributaries are home to the Virgin spinedace <em>Lepidomeda mollispinis</em>. Moapa dace <em>Moapa coriacea </em>and Moapa White River springfish <em>Crenichthys baileyi moapae </em>are found in thermal springs that form the Moapa River, and Moapa speckled dace <em>Rhinichthys osculus moapae </em>is generally found below the springs in cooler waters. The agricultural heritage of the Virgin–Moapa River system resulted in numerous diversions that increased as municipal demands rose in recent years. In the early 1900s, trout were introduced into some of the cooler tributary streams, adversely affecting Virgin spinedace and other native species. The creation of Lake Mead in 1935 inundated the lower 80 km of the Virgin River and the lower 8 km of the Moapa River. Shortly thereafter, nonnative fishes invaded upstream from Lake Mead, and these species have continued to proliferate. Growing communities continue to compete for Virgin River water. These anthropogenic changes have reduced distribution and abundance of the native Virgin–Moapa River system fish fauna. The woundfin, Virgin River chub, and Moapa dace are listed as endangered, and the Virgin spinedace has been proposed for listing. In this paper we document how the abundance of these species has declined since the Endangered Species Act of 1973. Currently, there is no strong main-stem refugium for the Virgin River native fishes, tributary refugia continue to be shortened, and the Moapa River native fishes continue to be jeopardized. Recovery efforts for the listed and other native fishes, especially in the Virgin River, have monitored the declines, but have not implemented recovery actions effective in reversing them.


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