Browsing All Posts filed under »wetland«

When drought eliminates fish…

March 30, 2019


  Droughts can lead to lasting changes in the condition of wetlands.  For example, as drying occurs water levels drop and light penetration improves, which allows aquatic plants in the seed bank to germinate.  By stabilizing sediments, outcompeting algal plankton and  providing refuge to zooplankton grazers, newly established stands of aquatic plants can cause originally […]

Constructed wetlands can be traps for wildlife

March 30, 2019


  In urban areas, natural wetlands are rapidly being replaced by constructed wetlands designed to treat stormwater.  While stormwater wetlands provide  habitats for wildlife, there are concerns that their often high concentrations of nutrients, heavy metals and pesticides may have a harmful impact on animals that are attracted to them – in other words, that […]

Wetland fish sampling

January 14, 2019

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How best to sample fish communities in lakes and wetlands?  Canadian biologists set out to develop a cost-effective sampling strategy that captured a high proportion of fish species.  Using a 9 m × 1.8 m seine net with 3 mm mesh, they collected fish from wetlands in Lake Ontario, Lake Erie, Lake Huron and the upper […]

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 […]

Paying to restore urban streams

March 25, 2018

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Rivers and streams provide many ecosystem services, including the supply and purification of water, climate regulation, flood protection, fisheries, aesthetic values and recreation.  In urban settings, the loss of stream ecosystem services as a result of pollution, erosion and habitat degradation has prompted widespread attempts at environmental repair. However, although levels of investment in urban […]

Lateral thinking on riverbank erosion

September 25, 2017

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Although bank erosion is often thought of as problem that has to be addressed through engineered stabilization, the lateral migration of meandering streams is a natural mechanism that redistributes channel sediment and maintains habitat diversity. New riparian zones are formed as sediment is deposited on the inside of bends and colonised by vegetation.  Meandering creates […]