Featured Research

from universities, journals, and other organizations

River regulation influences land-living animals

Date:
February 28, 2013
Source:
Ume universitet
Summary:
Forest-living insects and spiders become less abundant and birds are adversely affected along regulated rivers. Three different studies by ecologists show that river regulation has a negative effect also on land-living animals.

Forest-living insects and spiders become less abundant and birds are adversely affected along regulated rivers. Three different studies by ecologists at Ume University in Sweden show that river regulation has a negative effect also on land-living animals.

Related Articles


It is already well known that river regulation influences salmon migration, aquatic insects and streamside vegetation, but effects on land-living animals have been poorly studied.

When free-flowing rivers become regulated, there is a reduction in the number of aquatic insects that, during spring and summer, emerge and fly onto land where they become food for land-living animals.

"Our studies show that the number of flying insects is lower along regulated rivers than along free-flowing rivers. This results in fewer forest-living insects and spiders along regulated rivers, as the resource they feed upon -- emergent aquatic insects -- is reduced," says ecologist Micael Jonsson, the lead author on two of the articles.

Together with a group of researchers, he has compared the abundance of insect-feeding animals along similar river stretches at four regulated and four free-flowing large rivers in northern Sweden and the Finnish Kemi River. Along these rivers, flying and ground-dwelling insects were caught. The flying insects were caught with a net mounted on the top of a moving car, and the ground-dwelling insects and spiders were caught in pitfall traps.

The research team also shows that birds are adversely affected by river regulation. Besides a standardised bird survey, nest boxes were used to investigate breeding success of insectivorous birds. The study species, the Pied Flycatcher, is a relatively common species and prefers to use nest boxes.

The results show that adult Pied Flycatchers breeding along regulated rivers lost more weight after their eggs were hatched and fewer of the chicks survived, because their food resource -- the insects -- was less abundant. Along one of the regulated rivers, the survival of the chicks was even lower than what is required for the species to persist.

There were also signs of whole bird communities being impacted by river regulation. Aquatic insect emerge and fly onto land before terrestrial insects peak in numbers. The aquatic insects are therefore an important food resource for birds early in the season, while, normally, birds are seen foraging away from aquatic systems later in the season.

"We could see that such seasonal movements of whole bird communities differed between regulated and free-flowing rivers," says Micael Jonsson.

That the effects are still visible half a century after regulation of these rivers was initiated clearly indicates that the changes are permanent. The studies also highlight the fact that different types of ecosystems influence each other via resource flows, and that changes in one ecosystem therefore affect plant and animals in nearby ecosystems.

"Therefore, there are even stronger reasons to question the use of biological insecticides to reduce the numbers of mosquitoes along rivers in central Sweden and elsewhere in the world, because it most likely results in poorer living conditions for a range of land-living animals."

The studies are published in the international journals River Research and Applications, Ibis, and Ecological Research.


Story Source:

The above story is based on materials provided by Ume universitet. Note: Materials may be edited for content and length.


Journal References:

  1. M. Jonsson, P. Deleu, B. Malmqvist. PERSISTING EFFECTS OF RIVER REGULATION ON EMERGENT AQUATIC INSECTS AND TERRESTRIAL INVERTEBRATES IN UPLAND FORESTS. River Research and Applications, 2012; DOI: 10.1002/rra.2559
  2. Darius Strasevicius, Micael Jonsson, Erik Nyholm, Bjrn Malmqvist. Reduced breeding success of Pied Flycatchers Ficedula hypoleuca along regulated rivers. Ibis, 2013 DOI: 10.1111/ibi.12024
  3. Micael Jonsson, Darius Strasevicius, Bjrn Malmqvist. Influences of river regulation and environmental variables on upland bird assemblages in northern Sweden. Ecological Research, 2012. 27: 945-954

Cite This Page:

Ume universitet. "River regulation influences land-living animals." ScienceDaily. ScienceDaily, 28 February 2013. <www.sciencedaily.com/releases/2013/02/130228080238.htm>.
Ume universitet. (2013, February 28). River regulation influences land-living animals. ScienceDaily. Retrieved December 22, 2014 from www.sciencedaily.com/releases/2013/02/130228080238.htm
Ume universitet. "River regulation influences land-living animals." ScienceDaily. www.sciencedaily.com/releases/2013/02/130228080238.htm (accessed December 22, 2014).

Share This


More From ScienceDaily



More Earth & Climate News

Monday, December 22, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

New Fish Species Discovered, Setting Record for World's Deepest

New Fish Species Discovered, Setting Record for World's Deepest

Buzz60 (Dec. 22, 2014) A new species of fish is discovered living five miles beneath the ocean surface, making it the deepest living fish on earth. Jen Markham has the story. Video provided by Buzz60
Powered by NewsLook.com
Raw: Lava Inches Closer to Highway

Raw: Lava Inches Closer to Highway

AP (Dec. 21, 2014) Officials have opened a new road on Hawaii's Big Island for drivers to take care of their daily needs if encroaching lava from Kilauea Volcano crosses a highway and cuts them off from the rest of the island. (Dec. 20) Video provided by AP
Powered by NewsLook.com
Could Cheap Oil Help Fix U.S. Roads?

Could Cheap Oil Help Fix U.S. Roads?

Newsy (Dec. 21, 2014) As falling oil prices boost Americans' spending power, the U.S. government is also gaining flexibility from savings on oil. Video provided by Newsy
Powered by NewsLook.com
Raw: Russian Surfers Brave Icy Cold Waters

Raw: Russian Surfers Brave Icy Cold Waters

AP (Dec. 20, 2014) Surfers in Russia's biggest port city on the Pacific Ocean, Vladivostok, were enjoying the sport on Saturday despite below freezing temperatures and icy cold waters. (Dec. 20) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins