Use of Common Pesticide, Imidacloprid, Linked to Bee Colony Collapse

ScienceDaily (Apr. 5, 2012) — The likely culprit in sharp worldwide declines in honeybee colonies since 2006 is imidacloprid, one of the most widely used pesticides, according to a new study from Harvard School of Public Health (HSPH).

The authors, led by Alex Lu, associate professor of environmental exposure biology in the Department of Environmental Health, write that the new research provides "convincing evidence" of the link between imidacloprid and the phenomenon known as Colony Collapse Disorder (CCD), in which adult bees abandon their hives.

The study will appear in the June issue of the Bulletin of Insectology.

"The significance of bees to agriculture cannot be underestimated," says Lu. "And it apparently doesn't take much of the pesticide to affect the bees. Our experiment included pesticide amounts below what is normally present in the environment."

Pinpointing the cause of the problem is crucial because bees -- beyond producing honey -- are prime pollinators of roughly one-third of the crop species in the U.S., including fruits, vegetables, nuts, and livestock feed such as alfalfa and clover. Massive loss of honeybees could result in billions of dollars in agricultural losses, experts estimate.

Lu and his co-authors hypothesized that the uptick in CCD resulted from the presence of imidacloprid, a neonicotinoid introduced in the early 1990s. Bees can be exposed in two ways: through nectar from plants or through high-fructose corn syrup beekeepers use to feed their bees. (Since most U.S.-grown corn has been treated with imidacloprid, it's also found in corn syrup.)

In the summer of 2010, the researchers conducted an in situ study in Worcester County, Mass. aimed at replicating how imidacloprid may have caused the CCD outbreak. Over a 23-week period, they monitored bees in four different bee yards; each yard had four hives treated with different levels of imidacloprid and one control hive. After 12 weeks of imidacloprid dosing, all the bees were alive. But after 23 weeks, 15 out of 16 of the imidacloprid-treated hives -- 94% -- had died. Those exposed to the highest levels of the pesticide died first.

The characteristics of the dead hives were consistent with CCD, said Lu; the hives were empty except for food stores, some pollen, and young bees, with few dead bees nearby. When other conditions cause hive collapse -- such as disease or pests -- many dead bees are typically found inside and outside the affected hives.

Strikingly, said Lu, it took only low levels of imidacloprid to cause hive collapse -- less than what is typically used in crops or in areas where bees forage.

Scientists, policymakers, farmers, and beekeepers, alarmed at the sudden losses of between 30% and 90% of honeybee colonies since 2006, have posed numerous theories as to the cause of the collapse, such as pests, disease, pesticides, migratory beekeeping, or some combination of these factors.

"In Situ Replication of Honey Bee Colony Collapse Disorder," Chensheng Lu, Kenneth M. Warchol, Richard A. Callahan, Bulletin of Insectology, June 2012

Farmers of 800-Years-Ago Could Teach Us How to Protect the Amazon -- With Raised Farming Beds

ScienceDaily (Apr. 9, 2012) — In the face of mass deforestation of the Amazon, recent findings indicate that we could learn from its earliest inhabitants who managed their farmland sustainably. An international team of archaeologists and paleoecologists, including Dr. Mitchell Power, curator of the Garrett Herbarium at the Natural History Museum of Utah and assistant professor in the Department of Geography at the University of Utah, report for the first time that indigenous people, living in the savannas around the Amazonian forest, farmed without using fire.

These findings are published April 9, 2012, in the Proceedings of the National Academy of Sciences.

The research could provide insights into the sustainable use and conservation of these globally-important ecosystems, which are being rapidly destroyed. Pressure on the Amazonian savannas today is intense, with the land being rapidly transformed for industrial agriculture and cattle ranching.

By analyzing records of pollen, charcoal and other plant remains like phytoliths spanning more than 2,000 years, the team has created the first detailed picture of land use in the Amazonian savannas in French Guiana. This gives a unique perspective on the land before and after the first Europeans arrived in 1492.

The research shows that the early inhabitants of these Amazonian savannas practiced 'raised-field' farming, which involved constructing small agricultural mounds with wooden tools. These raised fields provided better drainage, soil aeration and moisture retention: ideal for an environment that experiences both drought and flooding. The fields also benefited from increased fertility from the muck continually scraped from the flooded basin and deposited on the mounds. The raised-field farmers limited fires, and this helped them conserve soil nutrients and organic matter and preserve soil structure.

"We used radiocarbon dating to establish the age of the raised beds," said Dr. Mitchell Power. We came to the conclusion that corn pollen we found dated to 800 years ago by dating charcoal deposits from above and below the sediment where the pollen was found."

It has long been assumed that indigenous people used fire as a way of clearing the savannas and managing their land. However, this new research shows that this was not the case here. Instead, it reveals a sharp increase in fires with the arrival of the first Europeans, an event known as the 'Columbian Encounter'. The study shows that this labor-intensive approach to farming in the Amazonian savannas was lost when as much as 95 percent of the indigenous population was wiped out as a result of Old World diseases, brought by European settlers.

The results of this study are in sharp contrast with what is known about the Columbian Encounter's impact on tropical forest, where the collapse of indigenous populations after 1492 led to decreased forest clearance for agriculture, which in turn, caused a decline in burning. This study shows that high fire incidence in these Amazonian savannas is a post-1492, rather than pre-1492, phenomenon.

"Our results force reconsideration of the long-held view that fires were a pervasive feature of Amazonian savannas, said Power"

Dr José Iriarte of the University of Exeter, lead author on the paper, said: "This ancient, time-tested, fire-free land use could pave the way for the modern implementation of raised-field agriculture in rural areas of Amazonia. Intensive raised-field agriculture can become an alternative to burning down tropical forest for slash and burn agriculture by reclaiming otherwise abandoned and new savannah ecosystems created by deforestation. It has the capability of helping curb carbon emissions and at the same time provide food security for the more vulnerable and poorest rural populations."

Professor Doyle McKey of the University of Montpellier said: "Amazonian savannas are among the most important ecosystems on Earth, supporting a rich variety of plants and animals. They are also essential to managing climate. Whereas savannas today are often associated with frequent fire and high carbon emissions, our results show that this was not always so. With global warming, it is more important than ever before that we find a sustainable way to manage savannas. The clues to how to achieve this could be in the 2,000 years of history that we have unlocked."

Dr Francis Mayle of the University of Edinburgh said: "We've got an unprecedented record of these Amazonian savannas that completely overturns previous assumptions about the way in which ancient cultures utilized these globally-important ecosystems."

Dr Stephen Rostain of CNRS said "These raised-field systems can be as productive as the man-made black soils of the Amazon, but with the added benefit of low carbon emissions."

The study was carried out by a team from the University of Exeter (UK), Natural History Museum of Utah (US), Centre National de la Recherche Scientifique (France), University of Edinburgh (UK), Université Montpellier II and Centre d'Ecologie Fonctionnelle et Evolutive (France). It was funded by two CNRS Programmes ('Amazonie' and 'Ingénierie Ecologique'), the Arts and Humanities Research Council and The Leverhulme Trust.

The research featured in the PNAS article highlights two areas of active research at the Natural History Museum.

Agricultural industrialization

In recent years, investment in excess of three billion yuan has been devoted to furthering agricultural industrialization, an important part of the national program for enhancing the international competitiveness of Chinese agriculture. In 2004 alone the government set up 35 agricultural programs, supported by 30 million yuan from the Central Government, over 50 million yuan from local governments, some 100 million yuan of bank loans and more than 600 million yuan raised by enterprises and farmers.

Now a pattern has been formed, with 582 key national enterprises and over 2,000 key provincial enterprises as spearhead, and agencies of various forms connecting farmers with the production base. Leading enterprises in certain sectors, e.g., corn processing, dairy industry and chicken production, have taken major market share and play an increasingly important role in the development and pricing of their respective industries.

Since 2003, the state has set up six types of demonstration projects for the industrialization of modern agro-technology, so as to promote the use of advanced technology for agricultural production, and enhance foreign earnings from exports of farm products.

These projects include industrialization of breeding and cultivation of excellent new varieties and fine strains; high-efficiency, eco-friendly planting and aquatic breeding technology; water-saving and precision technologies; downstream processing of agricultural and ancillary products; pollution-free inputs (e.g., fertilizer and fodder) and the establishment of an agricultural information platform. The "downstream processing of main agricultural products project" was listed as an important sci-tech project during the 2000-2005 Five-Year Plan period. It aims at developing key technologies and equipment for downstream processing of staple agricultural products, research into integrated quality control systems and the quick testing of agro-product technology and equipment. Once completed, some of China's technological aspects will meet the advanced international standard. Meanwhile, the "dairy industry development" and "water-saving agriculture" projects have been listed among important sci-tech application programs initiated by the Ministry of Science and Technology.