 Wysłany: Sob 4:46, 02 Lis 2013 Temat postu: if the stream is dry and the water is lower |
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| Drought's affects on U.S. river ecosystems affecting native fish
MANHATTAN, Kan., June 6 () -- Persistent drought in North America has caused "a conservation crisis" for native fish communities, a Kansas State University researcher reported.Biology Professor Keith Gido and his team studied state and federal endangered and threatened fish species in river ecosystems including the Arkansas,[url=http://www.parajumpersjackenoutlet.de/]parajumpers damen[/url], Kansas, Gila,[url=http://www.parajumpersjackenoutlet.de/]parajumpers jacken outlet[/url], San Juan, Red and Platte rivers, a university release reported Thursday."A couple of key species that we have been studying have virtually disappeared where they historically were abundant," Gido said.As an example he cited silver chub, noting that more than 300 were observed in the Ninnescah River in southern Kansas in summer 2011. After a second consecutive year of severe drought, his team saw three silver chub during their sampling in 2012.Gido said they found zero silver chub in spring 2013."We are in a conservation crisis," he said. "Our fish communities have changed dramatically and we are losing a lot of native species."Two activities -- river fragmentation and groundwater withdrawals -- have significant impact on aquatic systems and native fish species in the Great Plains, he said, and when combined with the drought result in dramatically reduced fish communities and lower species diversity.River fragmentation occurs when barriers such as dams break up the long sections of connected river and create shorter segments."We have seen a gradual decline in native diversity over time," Gido said. "The drought exacerbates any of the effects because with fragmentation, if the stream is dry and the water is lower, the fish are unable to move around a barrier." |
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