Nevertheless, memories of the dam remain, and by digging into the soils of the basin, UW-Madison researchers are now unearthing them. Writing in a special issue (December) of Restoration Ecology, they report the discovery of two superimposed patterns of soil properties that chronicle distinct stages in the basin’s history: its decades of submersion, and its emptying when the dam was breached and removed.
“In our analysis, we were able to pick up those different soil patterns, which was pretty exciting,” says soil science professor Nick Balster, who led the study with doctoral candidate Ana Wells and landscape architecture professor John Harrington. “We could see the chemical and physical patterns that were created both by the inundation (of the land) and by the draining.”
Fascinating as those traces of the past are, however, what they mean for the future is the real question, Balster says. After seeding the basin with prairie species, the scientists are now waiting to see if the soil patterns affect the growth and distribution of the plants, and their ability to stand up against weedy, invasive competitors.
“By doing this research, we’re asking the question, ‘How much do soils matter in the restoration of these basins?’” Balster says. “As people who love to study soil we’re going to say, ‘A lot! Soils likely drive the whole thing.’ But as scientists, we don’t know yet.”
Answering that question is becoming more and more pressing. During the past three decades, hundreds of dams nationwide have reached the end of their lives, forcing dam owners to make costly repairs or — increasingly — to remove the structures. With some 3,800 dams to its name — or as many as 10,000, if small, unregulated structures are counted — Wisconsin leads the nation in total dams and has pulled more than 130. States such as California, Pennsylvania and Tennessee have taken out scores of dams as well.
The trend toward removal rather than repair has been driven in part by anglers and river enthusiasts, who justifiably welcome the return the free-flowing rivers and cold-water streams. But the outcome for the once-flooded lands is less certain. Many reports suggest they become havens for aggressive, invading plants such as reed canary grass, which has already consumed hundreds of thousands of acres in Wisconsin and other states.
The researchers’ work at Franbrook Farm, where the Beers Dam was removed in 2003, has now begun to yield some intriguing clues as to why this might be. For one, the scientists found fundamental differences in nutrient levels and physical structure between the knee-deep sediments that were deposited over the dam’s lifetime and the original soils buried beneath. Most striking, they say, is how uniform the spatial composition of the sediments is when compared to the patchy structure of buried soils. And this lack of chemical and physical variability might be one reason why weeds tend to thrive.
“Because you don’t have the patterns of heterogeneity that allow diverse plant communities to establish, invasive species can come in and move quickly through the area,” says Harrington.
At the same time, the sediments also contained definite gradients in density, moisture and other factors, which were laid down when the dam was breached. Finer sediments, for instance, were picked up by the rushing waters and carried closer to the spot where the dam once stood, while heavier, coarser particles tended to move less and settle farther out.
These gradients in particle size also dictate how some nutrients are distributed on the landscape, says Balster. For example, the team found higher concentrations of phosphorus, which binds preferentially to fine particles, closer to the dam‘s former location than farther away.
The scientists’ next goal is to figure out what all this means for their prairie restoration — which isn’t to say they’re rooting necessarily for the native plants.
”If we wanted to, with the expertise on our team, we could likely achieve a restoration of this site, by, say, removing the sediments,” says Balster. “But we’re interested in studying the drivers for restoration. We want to understand the process both above and belowground.”
The research was supported by the Franbrook Farm Foundation in cooperation with the UW-Madison College of Agricultural and Life Sciences and the state of Wisconsin’s Non-Point Source Pollution Project.
Madeline Fisher | Newswise Science News
Preservation of floodplains is flood protection
27.09.2017 | Technische Universität München
Conservationists are sounding the alarm: parrots much more threatened than assumed
15.09.2017 | Justus-Liebig-Universität Gießen
University of Maryland researchers contribute to historic detection of gravitational waves and light created by event
On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...
Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.
Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....
Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).
When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...
Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.
How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...
Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.
It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...
17.10.2017 | Event News
10.10.2017 | Event News
10.10.2017 | Event News
20.10.2017 | Information Technology
20.10.2017 | Materials Sciences
20.10.2017 | Interdisciplinary Research