Browsing All Posts filed under »community«

How the food web affects river restoration

October 8, 2018

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River restoration commonly  concentrates on improving habitat quality for threatened fish populations.  However, because stream fish are strongly influenced by food availability, competition and predation, a case can be made for also incorporating food web modelling into the restoration process.  A group of environmental scientists developed an ecosystem model and applied it to a river-floodplain […]

Research on insect emergence warms up

October 8, 2018

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Long-term data show that climate change affects ecosystem functioning and the body size distributions of animal species, but more information is needed to understand the mechanisms underlying these changes.  There’s a need for experimental studies that take account of linkages between the aquatic and terrestrial environment and that simulate changes in the intensity and frequency […]

Floodplain fisheries and overexploitation

October 8, 2018

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The floodplain fishery in the Pantanal region of South America, one of the biggest wetlands in the world,  illustrates the difficulties often faced in managing resources in complex, highly changeable environments.  In the late 1970s and early 1980s, traditional small-scale commercial fishers accounted for around three-quarters of the fish catch.  In the absence of scientific […]

Worms, midges and the greenhouse effect

July 5, 2018

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Severely impacted aquatic environments such as urban wetlands and wastewater treatment ponds are designed to treat large amounts of carbon and nitrogen, which raises concerns about their potential greenhouse gas emissions.  Because pollution-tolerant worms (oligochaetes) and insects (midges) can reach very high densities in such systems, it’s possible that their activities influence  the flux of […]

How delayed is the flow-on effect?

July 5, 2018

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It’s generally accepted that river flows have a major influence on the structure of stream communities, but what’s the lag time from river discharge to community expression?  This question is particularly relevant for headwater streams that are vulnerable to seasonal drying or the over-extraction of groundwater, where changes in flow often lead to successional changes […]

Triggers for algal blooms: peak temperatures aren’t always important

July 5, 2018

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There are concerns that human impacts  on freshwater systems – particularly temperature increases linked to climate change and nutrient enrichment caused by run-off and pollution – are encouraging the spread of blue-green algae (cyanobacteria) capable of generating toxic blooms that threaten human and animal health.  One such case is the recent spread of Cylindrospermopsis raciborskii, […]

Helping to resolve the plankton paradox

March 26, 2018

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The richness of plant plankton communities in natural ponds and small lakes is very high – typically up to about 80 species at any one time in most systems. However, ecological theory predicts that the number of coexisting species should be no greater than the number of limiting resources, and normally in the case of […]