Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


K-State researchers study response of prairie ecosystem


In face of changes in precipitation variability, climatic extremes

What does Kansas’ weather and life have in common? In the words of Forrest Gump, both are like a box of chocolates. "You’re never sure what you’re going to get." Rain or drought. Drought or rain.
Concerns about future climate changes resulting from human activities often focus on the effects of increases in average air temperatures or changes in average precipitation amounts. But climate models also predict increases in climate extremes such as more frequent large rainfall events or more severe droughts. This aspect of climate change can lead to an increase in climatic variability without accompanying changes in average temperatures or total precipitation amounts, according to a report by a team of researchers at Kansas State University.

The team, headed by Alan Knapp, a university distinguished professor of biology, and John Blair and Phil Fay, professors of biology, has been studying how grasslands respond to increases in the variability of rainfall patterns to better understand how rapidly and to what extent ecosystems might respond to a future with a more extreme climate. Their findings appear in the latest issue of Science.

A key feature of the four-year field study is that the team was able to construct 12 rainfall "shelters" on the Konza Prairie -- essentially greenhouses with clear plastic roofs but without sidewalls -- that allowed the researchers to collect and store rainfall as it occurred and use it in turn to manipulate rainfall patterns in large grassland plots.

The research team was able to alter the rainfall variability by using the collected rainfall to increase the size of individual rainfall events and lengthen the periods of time between rainfall events by 50 percent, thus effectively increasing the severity of dry periods between storms without altering the total amount of precipitation received during the growing season in their experimental plots.

"All plots get the same amount of rain, but there are different durations in the dry periods between events and the size of the storms is different," Knapp said of the. "We’re changing just the distribution of rain and the intensity of the rain, but we’re not changing the amount that occurs on the prairie."

After four years, researchers discovered "a host of changes" in the tallgrass prairie as a result of just altering the patterns of rainfall and not the amount of rainfall. When intact, native grassland plots exposed to more variable rainfall patterns were compared to plots that received natural rainfall patterns, the researchers found that the physiological vigor of the grasses decreased as did the overall productivity or growth of all plants combined. More variable rainfall patterns led to lower amounts of water in the soil in the upper 30 centimeters of soil. Since this is the soil depth where most plant roots occur and where soil microbes are most abundant, grasses were more water stressed and the activity of below ground organisms was reduced. Overall, more extreme rainfall patterns reduced the rate of carbon cycling in this grassland by lowering the uptake of carbon dioxide by the plants above ground and slowing carbon dioxide release by roots and microbes below ground.

"We found a significant reduction in the amount of grass growth and productivity, just by changing the pattern of rainfall but not by changing the total amount," Knapp said. "We saw significant reductions in below ground activity of the roots and microbes; we found significantly more stress in the grasses -- they experience longer dry periods between storms.; they can’t use the big rainfall events as effectively as they can the more frequent smaller ones and so we see greater water stress in the dominant grasses."

The group’s study as part of the Long-Term Ecological program at Konza Prairie, is the first to focus on and manipulate climate variability in an intact ecosystem without altering the climate average. Because all of the responses measured are similar to those that would occur under drought conditions, the results suggest that increased rainfall variability when combined with projected higher temperatures and decreased rainfall amounts may lead to even greater impacts on ecosystems than previously anticipated.

"This is a phenomenon of global importance, not just Kansas," Knapp said. "An increase in precipitation extremes is likely to occur everywhere. The kinds of climate changes that are likely to occur here and elsewhere will have measurable effects upon the resources that we depend upon. Those resources can be grassland resources or they can be cropland resources but it’s very likely that this change in climate, this increase in extreme storm events, this increase in rainfall variability will have measurable effects in a fairly short period of time."

Alan Knapp | EurekAlert!
Further information:

More articles from Ecology, The Environment and Conservation:

nachricht Dispersal of Fish Eggs by Water Birds – Just a Myth?
19.02.2018 | Universität Basel

nachricht Removing fossil fuel subsidies will not reduce CO2 emissions as much as hoped
08.02.2018 | International Institute for Applied Systems Analysis (IIASA)

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Space observation with radar to secure Germany's space infrastructure

Satellites in near-Earth orbit are at risk due to the steady increase in space debris. But their mission in the areas of telecommunications, navigation or weather forecasts is essential for society. Fraunhofer FHR therefore develops radar-based systems which allow the detection, tracking and cataloging of even the smallest particles of debris. Satellite operators who have access to our data are in a better position to plan evasive maneuvers and prevent destructive collisions. From April, 25-29 2018, Fraunhofer FHR and its partners will exhibit the complementary radar systems TIRA and GESTRA as well as the latest radar techniques for space observation across three stands at the ILA Berlin.

The "traffic situation" in space is very tense: the Earth is currently being orbited not only by countless satellites but also by a large volume of space...

Im Focus: Researchers Discover New Anti-Cancer Protein

An international team of researchers has discovered a new anti-cancer protein. The protein, called LHPP, prevents the uncontrolled proliferation of cancer cells in the liver. The researchers led by Prof. Michael N. Hall from the Biozentrum, University of Basel, report in “Nature” that LHPP can also serve as a biomarker for the diagnosis and prognosis of liver cancer.

The incidence of liver cancer, also known as hepatocellular carcinoma, is steadily increasing. In the last twenty years, the number of cases has almost doubled...

Im Focus: Researchers at Fraunhofer monitor re-entry of Chinese space station Tiangong-1

In just a few weeks from now, the Chinese space station Tiangong-1 will re-enter the Earth's atmosphere where it will to a large extent burn up. It is possible that some debris will reach the Earth's surface. Tiangong-1 is orbiting the Earth uncontrolled at a speed of approx. 29,000 km/h.Currently the prognosis relating to the time of impact currently lies within a window of several days. The scientists at Fraunhofer FHR have already been monitoring Tiangong-1 for a number of weeks with their TIRA system, one of the most powerful space observation radars in the world, with a view to supporting the German Space Situational Awareness Center and the ESA with their re-entry forecasts.

Following the loss of radio contact with Tiangong-1 in 2016 and due to the low orbital height, it is now inevitable that the Chinese space station will...

Im Focus: Alliance „OLED Licht Forum“ – Key partner for OLED lighting solutions

Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP, provider of research and development services for OLED lighting solutions, announces the founding of the “OLED Licht Forum” and presents latest OLED design and lighting solutions during light+building, from March 18th – 23rd, 2018 in Frankfurt a.M./Germany, at booth no. F91 in Hall 4.0.

They are united in their passion for OLED (organic light emitting diodes) lighting with all of its unique facets and application possibilities. Thus experts in...

Im Focus: Mars' oceans formed early, possibly aided by massive volcanic eruptions

Oceans formed before Tharsis and evolved together, shaping climate history of Mars

A new scenario seeking to explain how Mars' putative oceans came and went over the last 4 billion years implies that the oceans formed several hundred million...

All Focus news of the innovation-report >>>



Industry & Economy
Event News

New solar solutions for sustainable buildings and cities

23.03.2018 | Event News

Virtual reality conference comes to Reutlingen

19.03.2018 | Event News

Ultrafast Wireless and Chip Design at the DATE Conference in Dresden

16.03.2018 | Event News

Latest News

For graphite pellets, just add elbow grease

23.03.2018 | Materials Sciences

Unique communication strategy discovered in stem cell pathway controlling plant growth

23.03.2018 | Agricultural and Forestry Science

Sharpening the X-ray view of the nanocosm

23.03.2018 | Physics and Astronomy

Science & Research
Overview of more VideoLinks >>>