Category Archives: agriculture and farming

Poultry farms that go organic produce fewer antibiotic-resistant bacteria

In this study, poultry houses like this, that transitioned to organic practices and ceased using antibiotics, had significantly lower levels of drug-resistant and multi-drug resistant enterococci bacteria. (Photo/Amy R. Sapkota, University of Maryland)

In this study, poultry houses like this, that transitioned to organic practices and ceased using antibiotics, had significantly lower levels of drug-resistant and multi-drug resistant enterococci bacteria. (Photo/Amy R. Sapkota, University of Maryland)

With all the drug-resistant salmonella outbreaks of late, catching a food-borne illness is no longer a pesky health annoyance, but an increasingly menacing prospect. That’s why it’s nice to hear some calming news coming from a new study about the poultry industry. Researchers at University of Maryland have just published findings that show chicken farms going organic make for fewer drug-resistant bacteria.

The overuse of antibiotics on livestock has led to the evolution of super bacteria that no longer respond to drug treatments. Organic farms don’t use antibiotics, and the switch from conventional to organic cuts the presence of drug-resistant bacteria with dramatic impact.

Researchers compared enterococci bacteria levels — a classic culprit of drug-resistant infection in animals and people —  at 10 conventional large-scale poultry farms with 10 newly organic large-scale farms. The organic farms fared much better for bacteria, several as soon as one generation of chicken. The difference was nothing to bat an eyelash at either. On average, organic farms had three to four times fewer antibiotic-resistant bacteria than conventional farms.

Multi-drug resistant bacteria are of particular public health concern because they can be resistant to all available antibiotics, and are therefore very difficult to treat if contracted by an animal or human. (Photo/Amy R. Sapkota, University of Maryland)

“We initially hypothesized that we would see some differences in on-farm levels of antibiotic-resistant enterococci when poultry farms transitioned to organic practices,” explained Dr. Amy R. Sapkota, an Assistant Professor with the Maryland Institute for Applied Environmental Health in a press release. “But we were surprised to see that the differences were so significant…It is very encouraging.”

The study is the first of its kind to demonstrate a link between switching to organic practices and reduction in these hard-to-treat bugs. Researchers expect the drop in drug-resistant bacteria to become even more dramatic as more time passes, more farms go organic and reservoirs of drug-resistant bacteria dry up, according to a press release.

For more information you can read the full press release titled “Poultry farms that go organic have significantly fewer antibiotic-resistant bacteria,” go to the journal Environmental Health Perspectives (online August 10, 2011), or contact :

Kelly Blake
kellyb@umd.edu
301-405-9418
University of Maryland

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Cane toads heart climate change

Cane Toad, AKA Bufo marinus, AKA troublemaker extraordinaire (Photo/ Eli Greenbaum)

Cane toads like it hot, and with climate change poised to raise temps in Australia, this persistent, invasive species could soon be living it up even more.

At least that’s the word coming out of new research from the University of Sydney and presented at the Society for Experimental Biology’s annual conference in Prague.

A lot of what we hear about climate change focuses on habitat loss (cue rising sea levels) or species extinction (sorry red wolf and coral reefs), but here’s another way the pesky, poisonous cane toad can flip the amphibian bird to mankind – warmer climes mean prolific times as far as the toad is concerned.

“The negative effect of high temperature does not operate in cane toads, meaning that toads will do very well with human induced global warming,” said Professor Frank Seebacher from the University of Sydney in a press release.

Many of you reading this are probably familiar with the story of the cane toad, but here’s the quick shake down. In the mid 1930s, Australian biologists, hoping to stem the onslaught of beetles ravaging cane fields, introduced cane toads to Queensland and the Northern Territory. Unfortunately, toads passed on the beetles, instead turning their appetites towards lizards, snakes and other native wildlife. To compound factors, the toads secrete a toxic substance that can do a serious number on just about anything that tries to eat it. So the cane fields now have beetles and bucket loads of poisonous toads. Sigh.

And because of research by Seebacher, we now have a good idea that toads are going to thrive even more as temperatures rise from climate change. Warmer weather makes for stronger, or at least more efficient, heart and lungs in the cane toad, Seebacher found. And if that’s not unsettling enough, the study also states “the cane toad can adapt its physiology in response to a changing environment repeatedly and completely reversibly many times during its lifetime.”

Will nothing temper their proliferation?

Before you totally throw up your hands and say, “Why do I read this if all you’re going to tell me is bad news,” here’s a ray, or sliver, of hope. Maybe, just maybe, this phenomenon will prove true for other toads, ones we actually would like to see stick around. I’ll get back to you when Seebacher conducts that study.


Changing Chesapeake Bay acidity endangers oysters

New research shows that the shell growth of Crassostrea virginica from Chesapeake Bay could be compromised by current levels of acidity in some Bay waters. (Photo/Chris Kelly, UMCES Horn Point Laboratory)

Growing up at the mouth of the Lynnhaven River in Virginia, where the river meets the Chesapeake Bay and the bay meets the ocean, I can’t tell you how many mornings I woke up and looked out my window to see neighbors wading in rubber boots, harvesting oysters from the beds just off our riverbank. For some, like my neighbors, oysters were a way to connect with the land and make a little extra dough. For others it was their livelihood. The act was something that just was. It never occurred to me that the oysters could one day be gone.

That’s why I was especially alarmed to read this new report from the University of Maryland Center for Environmental Sciences. Rising acidity levels in the Chesapeake Bay are making it harder for oysters to grow their shells. I’ve heard the news before that rising ocean acidity from sources such as carbon dioxide can spell disaster for marine wildlife, but this new study shows that acidity is rising faster in the Chesapeake Bay than in the ocean and having a measurable impact on Bay wildlife.

“With oyster populations already at historically low levels, increasingly acidic waters are yet another stressor limiting the recovery of the Bay’s oyster populations,” said marine biologist Dr. Roger Newell of the UMCES Horn Point Laboratory in a press release.

But don’t turn around to blame climate change just yet. The story is a bit more nuanced than that, though the source of the problem still has to do with us. In the saltier areas of the bay, the acidity is going up, leading to thin shell growth that makes oysters more vulnerable to predators, including crabs. But in more freshwater portions of the Bay, acidity is actually going down, said the study, which looked at more than 20 years of historical water quality data from the Bay.

The difference seems to be not atmospheric carbon dioxide, but the base of the food chain. In freshwater areas along the upper Chesapeake, sewage and agricultural runoff cause phytoplankton blooms, which consume carbon dioxide and lower acidity, said the study. Sounds good at this point right? Here’s the catch. As phytoplankton drift through the Bay, they are eaten by animals and other bacteria, releasing the carbon dioxide that the plankton so diligently consumed in the first place. This carbon dioxide lingers in the water, leading to spikes in acidity in the saltier regions of the Bay near the ocean.

“While these variations in acidity may improve conditions for shellfish in some areas, they may also magnify detrimental impacts in others,” said lead author Dr. George Waldbusser of Oregon State University in a press release. “What our study indicates is there may be an important shifting baseline and without better measurements we will fail to fully understand impacts on estuarine biota.”

Beyond the science itself, this study highlights how connected and varied our environment is. It lays out a pathway of human-induced consequences to an ecosystem, and teaches that we need to look beyond one-to-one cause and effect. Erin Voigt, an undergraduate student who worked on the study puts it well. “The complex response of oyster shell formation to temperature, salinity, and acidity highlights the need to understand how the entire ecosystem is changing, not just acidity,” she said.

And that ecosystem includes us.

You can view the article online in the journal Estuaries and Coasts.


The Selfish Environmentalist: religion in Morocco and caring for the land

In the High Atlas Mountains of Morocco, abandonment of religious beliefs is transforming the wild.

High Atlas Mountains, Morocco (Photo/Jerzy Strzelecki)

For Morocco’s Amazig people, who long looked to their saints for guidance on how to manage their land, a loss of religion spells big changes for nature. Locals are shifting from a communal outlook to a more self-serving one, a switch that bears consequences for people and ecosystems alike, according to a new study in the journal Human Ecology. The study indicates that when people manage the land for themselves rather than the good of all, what’s here today could be gone, or at least different, tomorrow.

Historically, beliefs in local Islamic Saints encouraged a communal mindset when it came to managing resources in the High Atlas Mountains of Morocco. For instance, in spring, the Amazig would often set some pastures off-limits, saving them for harder times, a practice known as Agdal.

But as the Amazig abandon tradition, a new environment begins to take shape. Pablo Dominguez from the Universitat Autònoma de Barcelona in Spain and his colleagues observed and interviewed families from 80 households in Warzazt, Morocco, from 2003 to 2008. They found a close relationship between the loss of traditional religious beliefs and expansion of farmland and introduction of new sheep species.

The impacts of these practices are not yet fully understood, but one thing’s for certain, this study takes a fresh tack on natural resource management, emphasizing the ways religion plays a pivotal role in how cultures use and change their environment.


Migratory birds prefer organic

Going organic isn’t just a popular choice for eco-savvy dieters, turns out migratory birds like it too. A new study out of Lund University in Sweden shows that migrating birds lean towards green when it comes to large-scale monoculture farms, with higher abundances and diversity of birds choosing to stop at organic farms than conventional ones. The findings offer new crops for thought when it comes to managing agriculture for wildlife well-being.

The idea that organic farming is good for wildlife is nothing new. Farming practices that hit overdrive and heavy pesticide use have been linked to drops in wildlife populations. But previous studies focused largely on bugs or resident bird populations. Juliana Dänhardt and Martin Green of Lund University decided to take the research a step further, focusing on migratory bird species.

Migratory birds get hit with a double whammy when dealing with environmental stress. They contend with a lot of the same environmental pressures as resident birds, but enjoy the added baggage that comes from moving into a temporary living situation. These visitors tend to show up at tilling time to an unfamiliar landscape and must fuel up in a hurry before embarking on the next leg of their journey.

Dänhardt and Green wanted to see if organic farming and more diverse cropland would helped alleviate some of these pressures. In 2005, they and their team selected a dozen pairs of farms in Falsterbo, Sweden, one of the richest agricultural regions of the country. The pairs were set up to compare organic versus conventional and diverse versus simple crop farms. During the fall migratory season, they conducted bird surveys to see what happened. Dänhardt and her colleagues found the relationship between birds and farm preference to be a complicated one.

The strength of bird populations was all over the show. Some types of birds did prefer diverse organic farmland, while others were less discerning. And certain species, such as geese and golden plovers, showed a penchant for wide-open monoculture fields. But one overarching trend did emerge from the complexity. Turns out, birds that chose the wide-open fields also preferred the organic version.

At the moment, ag trends in Sweden lean towards encouraging crop diversity as a way to bolster wildlife populations, but this study indicates that supporting organic or low-impact farming practices on large-scale monoculture farms could be another method for helping out those hard-flying, fast-eating, stressed out migratory birds.

The study is published in the online early edition of the journal Oikos.


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