Greenversations

Each week we write about the science behind environmental protection. Previous Science Wednesdays.

It was 0630 and although the sun was beginning to rise, it was still very dark within the tropical forest. Following a 20 minute ride in a small boat, we had arrived at a remote trail on the island and were now navigating the trail to check the CO2/light traps set the night before. The illuminated traps were beacons in the sea of dark forest, and we hoped they’d be filled with mosquitoes. The forest was peaceful in the early morning light, except for the occasional bouts of grunting from the howler monkeys or an agouti crossing the trail.

I never imagined working at EPA would lead me to Barro Colorado Island (BCI), a former mountain top that became an island when the Panama Canal was created in the early 1900s. Now a natural monument, it was the setting of the inaugural sampling event for a joint project between EPA and the Smithsonian Tropical Research Institute (STRI).

The project explores the link between biodiversity, insect vectors (those capable of passing a pathogen one animal to another), and disease. The connection between biodiversity (the number and abundance of difference species) and disease is complicated, but we know that sometimes changes in biodiversity (specifically, the loss of structural diversity) can increase the abundance of certain disease-carrying vectors. In turn, this can increase the risk of humans coming into contact with the disease-transmitting vector. Human activities, such as encroaching into new areas to build houses or clear land for farming, can change local biodiversity.

The STRI-EPA project focuses on mosquitoes and how changing biodiversity in “natural” and anthropogenic landscapes affects vectors of public health importance.

Back at the lab, we began the monumental task of sorting through the traps’ contents. Thankfully, I was surrounded by insect experts who were able to show me exactly what to look for among the tiny copious critters. Microscope and forceps in hand, I started sorting and sorting…. Hours later, sorting complete, we separated mosquitoes and sandflies (another vector important to public health) by species into groups of 50 or fewer. Specimens were placed into vials and frozen. The samples will be analyzed later to see what kinds of pathogens the insects were carrying, if any.

Over this next year, sampling will continue at BCI. We plan to expand sampling into nearby, land-disturbed areas inhabited by people so that mosquito diversity and disease risk can be compared with that of BCI.

About the Author: Meghan Radtke, Ph.D. is an AAAS Science and Technology Policy Fellow at EPA. Her fascination with biodiversity and tropical forests inspired her to join the Biodiversity and Human Health research effort.

Each week we write about the science behind environmental protection. Previous Science Wednesdays.

The Amazon basin contains more than half the world’s remaining tropical rainforest, and is facing unprecedented changes that will have major impacts on biodiversity, regional hydrology and the global carbon cycle.

But the need for employment is causing tropical deforestation on a vast scale.

Stopping deforestation requires forest management strategies that provide jobs for people living in or near forests while also creating incentives for forest conservation. The andiroba tree (C. guianensis)- valued for the high-quality oil extracted from its seeds and for its mahogany-like timber—could provide this opportunity.

Collect the seeds, cut down the tree, or a little of both?

Through my research, I am looking at the intersection of conservation and economics related to harvesting C. guianensis. I am using ecological models with an economic component to answer the question: Under what ecological and market conditions would the collection of C. guianensis seed oil be favored and, conversely, under what ecological and market conditions would C. guianensis timber harvest be favored?

Since 2004, I have been measuring growth, survival and reproduction of C. guianensis trees at my research site in the Brazilian Agricultural Research Institute’s 1,200-hectare research forest in Acre, Brazil.

Using these measurements, I plan to fine-tune models about future tree growth under various management scenarios, as well as identify how different life stages, such as seedlings, saplings, mature trees, etc., contribute to growth of the entire tree population. For example, it is possible that leaving a certain number of reproducing trees per hectare would maintain a growing population, leaving other, non-reproductive trees to be harvested?

I will use the new model to determine sustainable harvest limits for both timber and seed, and then incorporate the results into a financial assessment of these two competing strategies to manage the species. To ensure that the tree population is maintained and that it generates income, I plan to compare the relative compatibility of timber vs. seed harvest.

After I finish writing up my results, I will return to Brazil to give a series of training workshops and seminars on my results so they can be applied to forest management practices. In addition, I will compile materials (including comic-book-like illustrated pamphlets) that break down my results into tools that can benefit forest residents and local nongovernmental organizations. By sharing my research results in this way, I hope that I can provide important information to the local Brazilian government and play a part in helping people living near the forest find a sustainable way to create income based on a standing (or managed) forest.

About the author: Christie Klimas is a PhD student at the University of Florida in the department of Forest Resources and Conservation. A 2004-2006 EPA Science to Achieve Results (STAR) Graduate Research Fellowship supported her Master’s Degree research.

For each month in 2009, the Year of Science — we will pose a question related to science. Please let us know your thoughts as comments, and feel free to respond to earlier comments, or post new ideas.

The Year of Science theme for September is Biodiversity and Conservation. Biodiversity is a catch-all term that refers to the variety of life at all levels, from the range of genes within in a breeding population (more genetic diversity helps to prevent inbreeding problems), to how many different species there are, all the way to the variety of different ecosystems. EPA scientists are exploring how biodiversity is linked to human health and well being.

How do you think biodiversity affects you?

Each week we write about the science behind environmental protection. Previous Science Wednesdays.

Recognizing that there is a need for more scientific studies characterizing the mechanistic pathways linking social stressors (deforestation, habitat fragmentation, climate change), biodiversity, and human disease transmission, EPA developed a Biodiversity and Human Health research initiative to develop and sponsor long-term and pilot research projects.

The Biodiversity and Human Health research projects are the first of their kind at EPA, in subject matter and approach. The approach is interdisciplinary, involving ecologists, public health specialists, social scientists, and earth scientists. One unique part of the studies is that decision-makers are included in the research process, so that new findings of scientific knowledge can quickly be put into practice.

Starting tomorrow, I’ll be making a field site visit to one EPA-sponsored research project.

Rick Ostfeld, of the Cary Institute of Ecosystem Studies is leading a project entitled “Mechanisms Linking Host Biodiversity to Lyme Disease Risk: An Experimental Approach” to investigate how differences in animal community composition affect Lyme disease transmission in Duchess County, NY.

People get Lyme disease by being bitten by a tick infected with the spirochete bacterium, Borrelia burgdorferi. Ticks acquire the Lyme disease bacterium by feeding on small mammals such as white-footed mice (Peromyscus leucopus) and chipmunks that are already infected.

Not all mammals are equally efficient or competent at transmitting the bacteria to ticks when fed upon. In fact, white-footed mice appear to be the most competent animal host reservoir of Lyme disease in the northeastern U.S. So, the more white-footed mice that are in the forest, the greater chance more ticks will be infected, and the greater chance you have of getting bitten by an infected tick.

In a previous blog, I mentioned that forest destruction and fragmentation in the U.S. have been shown to reduce mammalian species diversity, and to increase populations of the white-footed mouse. Rick and his team will be manipulating the composition of small mammals across a variety of forest plot types to see how high and low levels of mammal diversity may affect Lyme disease infection rates among feeding ticks.

In a seminal paper, Rick and his colleagues proposed the “dilution hypothesis” to help explain how high biodiversity can decrease the risk of Lyme disease transmission. It predicts that infection rates for a specific pathogen (e.g. Lyme disease bacterium) will be lower in highly diverse host communities. Why? The “incompetent” reservoir hosts dilute rates of transmission between vectors (ticks) and competent hosts (white-footed mice). With EPA support, Rick’s team will be collecting and analyzing field data to help characterize the scientific mechanisms that can explain how different levels of biodiversity affect Lyme disease risk.

For more information on EPA’s Biodiversity and Human Health activities, see:
http://www.epa.gov/ncer/biodiversity

About the author: Montira Pongsiri, PhD, MPH, is an Environmental Health Scientist in EPA’s Office of the Science Advisor.

NOTE: Tweet! Tweet!
Follow the action from our field trip. We’ll posting updates from EPA’s new research Twitter account: @useparesearch.

Each week we write about the science behind environmental protection. Previous Science Wednesdays.

About the Author: Melissa-Anley Mills is the news director for EPA’s Office of Research and Development. She joined the Agency in 1998 as a National Urban Fellow.

Usually I sit in a Dilbert-style cube-farm, a warm, calm, enveloping sea of beige, beige, and more beige. So it was a rare and truly delicious treat to be invited to tag along on a field visit. The mission was simple: help Dr. Montira Pongsiri communicate her biodiversity research examining the link between biodiversity, the abundance and composition of animals, and Lyme Disease risk. To do this, my colleague, Aaron Ferster, (who previously blogged about our trip) and I had to see the researchers in action. We wanted to bring this experience to others via the web, so we loaded up on the technologies that would help us do that, a blackberry for “microblogging” (or “tweeting” on Twitter), and still and video cameras.

This turned into an experiment for the communication crew – the first time someone had microblogged live to the EPA’s Twitter account from the field. The first challenge we encountered was, of course, technical: spotty cell phone service. Recording the time and saving tweets in draft mode until reaching cell coverage solved that. But the real challenge was keeping the tweets short and sweet. Twitter has a limit of 140 characters (including spaces!) for posts. But there was so much to say about what we were seeing: white-footed mice, voles, baby opossums, catbirds, warblers, thrushes and ticks, oh my!

So there we were in the forest, watching and learning, tapping away on the blackberry, capturing video and photos, and lending a hand to the researchers. You can see the fruit of this labor on EPA’s biodiversity web page. Here you can read the tweets, and see the slideshows. Soon we’ll post video clips, so stay tuned.

Let us know what you think, suggestions are welcomed. What you would like to see in future “Field Notes” or visits with researchers?

Hopefully, through the images you’ll get a taste of this exciting research. Maybe it will encourage you to consider an environmental career as a field researcher, maybe a science teacher could use this as a teaching module, but I hope one thing is clear to see, the passion and devotion that these researchers have to gather the scientific data necessary to protect the environment and public health

Each week we write about the science behind environmental protection. Previous Science Wednesdays.

About the author: Aaron Ferster, a science writer in EPA’s Office of Research and Development, is a regular contributor to Science Wednesday.

Last Spring, a pair of barred owls took up residence in the upper reaches of a tree just past the edge of our yard. They announced their presence during dinner one warm evening, a series of deep hoots in a pattern birders describe as “who-cooks-for-you.”

We caught a brief glimpse of one as it leaned off its perch and in a long, silent swoop faded into the shadows of the woods behind our house, disappearing like a ghost.

The owls didn’t disappear for long. The girls soon discovered a trove of owl pellets beneath the roost. By picking the pellets apart we learned what the owls were eating. Sometimes there were crayfish claws or fish scales, but the owl’s main course must have always included small mammals. Every pellet contained the tiny white vertebra and jaw bones of mice.

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	Curtis Tackett adds a handful of sunflower seeds to one of the small, humane traps the survey team sets to survey mammal diversity. After examining the small animals, the team sets them free. (Click image to enlarge.)

Could owls and other wild neighbors be good for health by reducing the relative abundance of tick-infected mice? Last week I got to tag along with a team of Yale researchers surveying mammal diversity in the forests of Connecticut, part of an EPA-funded effort to explore just such questions.

Naturally, the team is taking a much more scientific approach than sifting through a handful of owl pellets. Instead, they set out small aluminum traps to humanely capture a representative sample of the local small mammal population.

Every critter caught was identified, ear-tagged (if not previously captured, a regular occurrence), and weighed. Before they were set free, each animal was thoroughly inspected and any black-legged ticks found were collected for further analysis. After the first day, we joined forces with another team conducting a similar survey of birds, part of an ongoing population study now sharing their efforts with the Yale team.

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	Field coordinator Kim Tsao carefully examines each a white-footed mouse, counting and removing black-legged ticks for further analysis for the bacterium that causes Lyme disease. (Click image to enlarge.)

The few days I spent with the survey team is a small part of a larger, two-year study to better understand of the links between biological diversity, land use, and Lyme disease. I was happy to have the chance to escape the office for a few days in favor of the forest. It reminded me once again how fun it is to explore the woods and to learn more about our wild neighbors, some of which might prove to be important for our health.

About the author: When not wearing a big, fuzzy giant panda costume, Aaron Ferster is the science writer-editor for EPA’s Office of Research and Development. This is his first entry for Greenversations.

I knew I was in for an interesting day when my boss looked me over and asked: “How tall are you?” “Five-foot-eleven,” I replied, wondering how height might play into my next performance evaluation.

“Perfect! There’s a big box waiting for you in shipping. It’s your costume for the Pollution Prevention Week table we’re setting up outside the Metro. Dress light. I’m told it’s hot in that panda suit.” Thus began my life as Pandy Pollution, EPA’s spokes-panda. Thanks boss!

Pandy’s goal for Earth Day was to lure people over to EPA’s display table where they could help themselves to the brochures, pamphlets, coloring books, and other environmental education materials on “going green.”

The boss was right about one thing: it was hot in there. Even dressed in gym shorts and a tee-shirt, I started roasting as soon as I slipped into the panda suit. But if you want to attract attention, going out dressed as overstuffed panda character is just the ticket. Just about everyone coming off the metro came in for a closer inspection, and plenty of folks picked up educational materials. Some even stayed to chat with the coterie of EPA experts hanging around the table. Mission accomplished.

Playing panda is a great way to help spread the word about safeguarding the environment and protecting human health. Now, it seems, real giant pandas and other wild critters play an even bigger role. There is growing scientific evidence that there is a connection between the decline in the diversity of wildlife and the emergence and spread of certain diseases.

EPA scientists are working with colleagues around the globe to better understand the link between biological diversity—the variety of species of plants, animals, and other living things that make up natural ecosystems—and emerging infectious diseases such as Lyme disease and malaria. What the scientists learn will help EPA and other agencies share important information about protecting human health. Someday soon, there might even be a stack of brochures about the subject available at the EPA Earth Day display just outside the metro entrance. If you’re interested in stopping by, just look for the 5-foot-11-inch-tall giant panda—and be sure to tell Pandy I say hello.