Ecological impacts on aquatic macroinvertebrates following upland stream invasion by a ponded pasture grass (Glyceria maxima) in southern Australia

2004 ◽  
Vol 55 (7) ◽  
pp. 709 ◽  
Author(s):  
Amber Clarke ◽  
P. S. Lake ◽  
Dennis J. O'Dowd
Keyword(s):  
Ecosystem Engineer ◽  
High Capacity ◽  
Ecosystem Processes ◽  
Channel Morphology ◽  
Ecological Impacts ◽  
Freshwater Wetlands ◽  
Stream Channel ◽  
Pasture Grass ◽  
Functional Feeding Group ◽  
Sediment Matrix

Glyceria maxima (Reed sweet-grass), an emergent aquatic grass native to Eurasia, has naturalised in North America, New Zealand and southern Australia. Introduced as a ponded pasture species, it threatens native biodiversity and ecosystem processes in freshwater wetlands and waterways. We compared paired sections, either invaded or not invaded by G. maxima, of three upland streams in Gippsland, Victoria, Australia to infer its impacts on macroinvertebrate abundance, morphospecies density, and morphospecies and functional feeding group (FFG) composition. Its potential effects in altering sedimentation were explored by comparing stream channel morphology in paired stream sections at one site. Invasion by G. maxima appears to drive changes in macroinvertebrate morphospecies composition and FFG composition, reducing a diverse array of macroinvertebrates to a more uniform fauna. The estimated volume of plant/sediment matrix in a 50 m invaded stream section was around 1100 m3, nearly 15-fold greater than in an adjacent uninvaded stream section. Glyceria maxima is an autogenic ecosystem engineer, with the ability to convert sections of fast-flowing aerobic streams into partially anaerobic swamps. By generating a root-mat swamp with a high capacity to process nutrients, G. maxima may facilitate its own growth and spread, as well as that of secondary invaders.

scholarly journals Effect of the Hydraulic Characteristics of a Stream Channel and its Surroundings on the Runoff Hydrograph

10.14311/923 ◽  
2008 ◽  
Vol 48 (1) ◽  
Author(s):  
V. Matoušek
Keyword(s):  
Urban Areas ◽  
High Capacity ◽  
High Water ◽  
Throughput Capacity ◽  
Hydraulic Characteristics ◽  
Flood Wave ◽  
Stream Channel ◽  
Storage Reservoirs ◽  
Smooth Channel ◽  
Rainfall Flood

The course and magnitude of a rainfall flood depends primarily on the intensity and duration of the rainfall event, on the morphological parameters of the watershed (e.g. its slope and shape), and on how to watershed has been exploited. A flood wave develops in the stream channel that drains the watershed, and it transforms while passing along the channel. This is particularly the case if the water spreads into floodplains and/or storage reservoirs while passing through the channel. This paper addresses an additional effect that has a significant influence on the magnitude and course of the flood wave but has not previously been addressed adequately, namely the effect of the hydraulic parameters of the stream channel itself on the transformation of a flood wave. The paper explains theoretically and shows on a practical example that a smooth channel with a high capacity significantly increases the magnitude and speed of a flood wave.Many flood events are unnecessarily severe just because the watershed is drained by a hydraulically inappropriate channel. The channel is large and smooth and therefore it gathers most of the flowing water during the flood event, producing high water velocity in the channel. As a result, the large and smooth channel accelerates the runoff from the watershed and constrains the spread of water into the floodplain. A high and steep flood wave is developed in the channel, and this floods areas with a limited water-throughput capacity (e.g. urban areas in the vicinity of hydraulic structures) downstream the channel. This paper offers a methodology for evaluating the ability of a channel to convey a flood wave safely and for recognizing whether a regulated channel should be subjected to restoration due to its inability to convey flood waves safely. 

A remote sensing based methodology of delineating stream channel morphology

2008 ◽  
Author(s):  
Mansoor Delali Leh ◽  
Sreekala Gopalapillai Bajwa ◽  
Indrajeet Chaubey ◽  
Jackson Cothren
Keyword(s):  
Remote Sensing ◽  
Channel Morphology ◽  
Stream Channel

scholarly journals Quantifying variability in stream channel morphology

2003 ◽  
Vol 39 (9) ◽  
Author(s):  
Kristie Trainor ◽  
Michael Church
Keyword(s):  
Channel Morphology ◽  
Stream Channel

scholarly journals Estimation of Soil Carbon Stocks of Urban Freshwater Wetlands in the Colombo Ramsar Wetland City and their Potential Role in Climate Change Mitigation

Wetlands ◽  
2021 ◽  
Vol 41 (2) ◽  
Author(s):  
D.D.T.L. Dayathilake ◽  
E. Lokupitiya ◽  
V.P.I.S. Wijeratne
Keyword(s):  
Climate Change ◽  
Atmospheric Carbon Dioxide ◽  
Climate Change Mitigation ◽  
High Capacity ◽  
Urban Ecosystems ◽  
Freshwater Wetlands ◽  
Soc Stock ◽  
Ramsar Wetland ◽  
Change Mitigation ◽  
Soc Stocks

AbstractWetlands hold significant potential for climate change mitigation due to their high capacity to sequester atmospheric carbon dioxide (CO2). Colombo, Sri Lanka was recently declared as one of the eighteen global Ramsar wetland cities. The current study represents the first attempt to quantify soil organic carbon (SOC) stocks held by the urban freshwater wetlands in Colombo. The study focused on the extensive urban wetland ecosystems of Kolonnawa wetland and Thalawathugoda wetland park. SOC stocks were determined using three parameters: depth of soil, bulk density, and SOC concentration. Loss on ignition method was used in quantifying SOC concentrations. Average SOC stocks, up to a depth of 60 cm at Kolonnawa wetland and Thalawathugoda wetland park were estimated at 504 ± 14 t C/ha and 550 ± 23 t C/ha, respectively. Furthermore, the total SOC stock at Kolonnawa wetland and Thalawathugoda wetland park were estimated at 198,408 ± 5564 t CO2eq and 66,313 ± 2764 t CO2eq, respectively. When considering global estimates, it was found that freshwater wetlands in Colombo hold a higher SOC stock than tropical wet forests and tropical dry forests. The current study highlights the importance of urban ecosystems in mitigating the ever increasing concentrations of atmospheric CO2 .

The impacts of ski slope development on stream channel morphology in the White River National Forest, Colorado, USA

Geomorphology ◽  
2009 ◽  
Vol 103 (3) ◽  
pp. 375-388 ◽  
Author(s):  
Gabrielle C.L. David ◽  
Brian P. Bledsoe ◽  
David M. Merritt ◽  
Ellen Wohl
Keyword(s):  
Channel Morphology ◽  
National Forest ◽  
Stream Channel ◽  
White River

Implications of legacy watershed disturbances for channel structure and salmon habitat availability under different low-flow levels: an analysis of 45 years of discharge–habitat relationships at Carnation Creek, British Columbia

2020 ◽  
Vol 77 (11) ◽  
pp. 1780-1793
Author(s):  
David A. Reid ◽  
Robin Pike ◽  
Stephen Bird ◽  
Peter Tschaplinski ◽  
David Wilford
Keyword(s):  
British Columbia ◽  
Coho Salmon ◽  
Aquatic Organisms ◽  
Channel Morphology ◽  
Channel Structure ◽  
Low Flow ◽  
Habitat Availability ◽  
Stream Channel ◽  
Ecological Requirements ◽  
Trade Offs

In streams where water availability is limited, conservative flow ranges are often adopted by water managers to ensure that streamflow is available to meet the ecological requirements of aquatic organisms. However, a variety of natural and anthropogenic disturbances can influence stream channel morphology and in-stream wood characteristics through time, potentially altering the availability of habitat at a given flow level. Using a 2D hydrodynamic modelling approach incorporating 45 years of detailed channel morphology data from Carnation Creek, British Columbia, this paper examines relationships between legacy (forestry-driven) watershed disturbance, changes to channel morphology, and habitat availability for juvenile coho salmon (Oncorhynchus kisutch) under nine flow levels. Results indicate that substantial variability in the abundance of salmonid habitat is present through time, even when modelled flow levels are held constant. Additionally, trade-offs were observed between availability of habitat types as discharge increased. Finally, modelling results indicate that habitat availability is reduced following historical harvesting. These findings suggest that legacy watershed disturbances affecting stream channel form and function are worth considering when allocating streamflow.

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