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Tag: "dams" at biology news

South America's vast pantanal wetland may become next everglades, UNU experts warn

...nges, such as altering the flood pulse by building dams or changing water quality by increasing the sediment load in rivers." "As economic development proceeded rapidly however, new stakeholders emerged along with the industrialization such as agriculture, modern cattle ranching, transport industry, hydr...

Proposal would allow wild animals to roam North America

... by 80 to 90 percent. With fewer beavers to create dams that raise water tables, fewer wetlands developed to support willows. Today, there are 60 percent fewer willows in parts of Colorado where beavers have declined. Similarly, after major predators became extinct in Montana and Wyoming, the number of m...

Wolves' top-down effect

Willow trees, riparian willow warblers and beaver dams once were bountiful in an area near the town of Banff, Alberta, Canada. But once wolves left this area, elk grew more plentiful, browsing heavily on young willows. Today, there is little trace of beavers, and sparrows have replaced the warblers in wh...

Contaminants linked to sturgeon decline in Columbia river

...the bottom-dwelling white sturgeon rarely navigate dams successfully making it difficult for them to expan...d some of the fish living in reservoirs behind the dams had concentrations of chemicals up to 20 times higher than the fish below Bonneville. The contaminat...

Iraq's marshes show progress toward recovery

...ding--local farmers had begun blowing up dikes and dams after the collapse of the Hussein regime in April 2003--and noted some reestablishment of native plants. Subsequent monitoring, done in collaboration with Iraqi scientists, estimated overall ecosystem health. Richardson and Hussain report that 39 per...

Beaver dams create healthy downstream ecosystems

...esearchers have found that ponds created by beaver dams raised downstream groundwater levels in the Colora...do River. They noted that water diverted by beaver dams is forced out of the natural stream channel and spreads across and down the valley for hundreds of m...

Virus may control Australia's

...e flooding in the 1970s the fish escaped from farm dams and took over the waterways. They can tolerate a wide range of water temperatures, salinity and pH levels. Carp can also survive and breed in polluted, poorly oxygenated water. "The fish grow to up to 20 kilograms or more in weight and each female c...

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