Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

UCSB researcher explores relationship between landscape simplification and insecticide use

06.09.2013
A new UCSB study that analyzed U.S. Department of Agriculture (USDA) Census of Agriculture data spanning two decades (1987-2007) shows that the statistical magnitude, existence, and direction of the relationship between landscape simplification –– a term used for the conversion of natural habitat to cropland –– and insecticide use varies enormously year to year.

While there was a positive relationship in 2007 –– more simplified landscapes received more insecticides –– it is absent or reversed in all previous years. The findings were published in the Proceedings of the National Academy of Science (PNAS).

The author, Ashley E. Larsen, a Ph.D. candidate in the Department of Ecology, Evolution and Marine Biology, built on an earlier study published in PNAS by extending the temporal dimension of that analysis. That study found a strong positive relationship between landscape simplification and insecticide use when examining 2007 data for seven midwestern states. Larsen's results also showed 2007 was positive, with increased land area in cropland leading to increased cropland treated with insecticides. But in 2002 and 1997, there was no statistically significant relationship; 1992 was negative (increased cropland but decreased insecticides); and 1987 was generally negative, but sometimes null depending on the model specification used.

According to Larsen, the increase in agricultural production over the past four to five decades has corresponded to massive changes in land use often resulting in large scale monocultures separated by small fragments of natural land. Ecological theory suggests that these simplified landscapes should have more insect pest problems due to the lack of natural enemies and the increased size and connectivity of crop-food resources.

"There is a debate currently in ecology about what the most efficient land use policy for agricultural production is," said Larsen. "Some think that complex landscapes are better, that they have minimal effect on the environment, in which case we'd need to grow over a larger area. Others think that we should grow in a concentrated area and preserve what isn't in agricultural production. This land sparing-land sharing debate is getting a lot of attention. My study results don't support either land sharing or land sparing. They just show that we don't really understand how either of those policies will affect insecticide use."

Larsen used USDA county-level data for 1987, 1992, 1997, 2002, and 2007 as well as from the National Agricultural Statistics Service Cropland Data Layer for 2007 for the same seven Midwestern states as the earlier PNAS analysis –– covering more than 600 counties in Iowa, Illinois, Indiana, Michigan, Minnesota, Ohio, and Wisconsin. She performed a single-year cross-sectional analysis for each year followed by a fixed effects analysis for all years together. She then compared fixed effects models with year, county, and year- and county-fixed effects. County-fixed effects control for unobserved effects, such as the soil quality unique to each county, and year effects control for year shocks, such as droughts shared by all counties in the study region.

With just county-fixed effects, the analysis showed a strong negative relationship between landscape simplification and insecticide use. When year-fixed effects were included, that relationship dropped to null. Including both year- and county-fixed effects, the relationship remained null and similar to the year-only model, indicating that year effects are very important.

"It would be very difficult to inform policy questions, such as land sparing or land sharing in terms of insecticide use, if the relationship between landscape simplification and insecticide use flip flops year to year," concluded Larsen. "These varied results make it hard to say a complex landscape is better or a simplified landscape is better. My next step would be to try to unlock what's behind that variation."

Julie Cohen | EurekAlert!
Further information:
http://www.ucsb.edu

More articles from Agricultural and Forestry Science:

nachricht New 3-D model predicts best planting practices for farmers
26.06.2017 | Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign

nachricht Fighting a destructive crop disease with mathematics
21.06.2017 | University of Cambridge

All articles from Agricultural and Forestry Science >>>

The most recent press releases about innovation >>>

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

Im Focus: Can we see monkeys from space? Emerging technologies to map biodiversity

An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.

Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

Touch Displays WAY-AX and WAY-DX by WayCon

27.06.2017 | Power and Electrical Engineering

Drones that drive

27.06.2017 | Information Technology

Ultra-compact phase modulators based on graphene plasmons

27.06.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>