Ecology

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Want Biodiversity? Love Your Enemies…Sometimes

Tuesday, August 1st, 2017

by Kristen Minogue

Three separate images of leaf infected by anthracnose, acorn with an insect hole and emerald ash borer.

Signs of three temperate forest enemies, left to right: Anthracnose (SERC), insect hole in an acorn (Jonathan Myers), emerald ash borer (Leah Bauer, USDA Forest Service Northern Research Station, Bugwood.org)

Walk through a forest in Maryland or Missouri, and you’ll probably find yourself surrounded by dozens of different tree species. Walk through a tropical forest in Brazil or Malaysia, and you’ll be surrounded by hundreds—in some forests, over 1,000. What’s behind this colossal difference in diversity? Scientists with the Smithsonian-led ForestGEO network came up with one morbid possibility: It may come down to having the right kind of enemy.

Earlier this summer, in a study in Science, researchers from 24 plots in the forest network from five continents pooled their data and detected a strange pattern: There’s a force at work in the tropics helping rare species thrive, a force that is much weaker in the cooler temperate zone.

Call it a clustering effect. The scientific term is “conspecific negative density dependence,” but it boils down to this: If too many trees of the same species grow in the same spot, they become magnets for enemies that slash their populations. In tropical forests, enemies generally knock them down just enough for new species to fill the gaps, without completely wiping out the first species. The result is a kaleidoscope forest with hundreds of species, many quite rare.

It may seem like a counterintuitive idea, that a lethal enemy could help sustain biodiversity. It can work when this thinning process prevents any one species from dominating.

“Just when a population is ready to take over, it catches a cold,” explained Sean McMahon, a co-author and forest ecologist with the Smithsonian Environmental Research Center (SERC). “And so it gets knocked back.”

Click to continue »

Scientists Turn Up the Heat on Herbivores and Their Food

Friday, July 28th, 2017

By Joe Dawson

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Japanese beetles make a meal of evening primrose leaves (Credit: Dejeanne Doublet/SERC)

Plants can seem pretty boring. They just sit there, after all. Sure, they can be pretty; they can make us sneeze. But what else do they do? A lot, it turns out. They are able to shift their own water and energy resources from leaves to stems to roots and back, grow tall or stay low and bushy, defend themselves through biological warfare, or warn their neighbors of danger. When doors get blocked, plants have ingenious ways of sneaking out through windows.

What, then, will plants do when humans spread a carbon dioxide blanket over the planet, warming it by burning fossil fuels? Research scientist Nate Lemoine of Colorado State University, with John Parker of the Smithsonian Environmental Research Center (SERC) and others, decided to investigate one such relationship with an experiment on the SERC campus in 2013 and 2014. Click to continue »

Tidings from the Sunset Coast (2)

Tuesday, July 25th, 2017

SERC-West Summer Intern Spotlights

by Ryan Greene

An intern in orange waders sprays a net hanging off the back of a boat.

Intern Elena Huynh helps clean a net during SERC’s annual zooplankton survey in San Francisco Bay. Credit: Ryan Greene/SERC

The Smithsonian Environmental Research Center’s (SERC) main campus is on the Chesapeake Bay in Maryland. SERC’s largest West Coast outpost, SERC-West, sits on the San Francisco Bay in California. To highlight SERC’s work out west, we’ve started Tidings from the Sunset Coast, a summer series about the life and times of SERC-West. Our first post explored California’s wet winter. This post features the stellar interns who are spending their summer at SERC-West.

Interns at the Smithsonian Environmental Research Center have the chance to work on independent projects while receiving personalized mentorship in a multidisciplinary atmosphere. Some people conduct experiments, others develop educational programs, and others (like me) write about the happenings at SERC. Simply put, SERC internships let you grow in whatever ways you want to be growing!

Check out the spotlights below to see what the interns at SERC-West are up to this summer. Click to continue »

Sharing Your Workspace with the Eastern Rat Snake

Sunday, July 16th, 2017

by Sara Richmond

Man holding snake in marsh

Scientist Guy Thompson holds up an eastern rat snake found at GCREW. (Credit: Gary Peresta/SERC)

To some, snakes are difficult creatures to love. Despite their reputation, however, snakes play critical roles in their environments by keeping populations of their prey in check. That’s why many scientists at the Smithsonian Environmental Research Center (SERC) have grown to appreciate their presence, particularly the eastern rat snake.

Eastern rat snakes, also known as black rat snakes or Pantherophis alleghaniensis to herpetologists, are a common sighting near SERC’s Global Change Research Wetland (GCREW). The GCREW project sits in roughly 170 acres of brackish marsh and is home to several experiments investigating rising sea levels, invasive species, global temperatures, carbon dioxide and other major players in global change. Click to continue »

Tidings from the Sunset Coast (1)

Wednesday, July 12th, 2017

How California’s Record-Setting Rains Are Reshaping the Ecology of San Francisco Bay

By Ryan Greene

Clouds hang over the San Francisco skyline.

The San Francisco skyline as seen from San Francisco Bay. Credit: Ryan Greene/SERC

The Smithsonian Environmental Research Center’s (SERC) largest West Coast outpost sits on San Francisco Bay in Tiburon, California. The Tiburon branch, affectionately known as SERC-West, serves as the nexus of SERC’s research activities on the western coast of North America. At a whopping 2,462 miles from SERC’s main campus on the Chesapeake Bay in Maryland, SERC-West can feel a bit remote. In an attempt to bridge this distance, we’re launching Tidings From the Sunset Coast,” a summer story series about all things SERC-West. The first snippet is a story about the wildly wet winter California experienced this year and what all this fresh water means for the marine life in San Francisco Bay. Enjoy!

A big band of clouds stretches from Hawaii to the western coast of North America.

Image from NASA’s VIIRS satellite show one of many “atmospheric rivers” which slammed the California coast this past winter. Credit: Jesse Allen and Joshua Stevens/NASA Earth Observatory

When it comes to rain in California, the last few years have been a feast-or-famine affair. After a bitter drought that sported some of the driest years on record, this past winter brought more precipitation than the northern parts of the state have ever documented. To put it lightly, the weather has been extreme. And while the wet winter has refilled reservoirs and beefed up the snowpack, leading Governor Jerry Brown to end the drought state of emergency in all but four counties, it has also wreaked its fair share of havoc.

Here at SERC-West, scientists have been following another part of this story: the bombardment of freshwater runoff that inundated San Francisco Bay this winter. All the fresh water from the rain drastically reduced the saltiness (a.k.a. salinity) of the Bay. For many plants and animals used to saltier water, this was simply too much to handle. The devastation has been widespread, and according to ecologist Andy Chang, who currently heads up SERC-West, in some areas, the changes to the ecosystem might be less than fleeting.

“We’re kind of expecting to see local extinctions of some species that were here before,” he says. Click to continue »

Time Travel, with Trees

Monday, July 10th, 2017

by Joe Dawson

Looking at the Kirkpatrick Marsh on the Rhode River, a time machine is not the first thing that comes to mind. Tall grasses dominate the landscape, with vertical PVC pipes popping up here and there and octagon-shaped chambers rising out of the wetland every ten paces or so. Take a step off the walkway, and you might lose a shoe. But 5 experiments on the marsh are designed to take sections of the marsh into the 22nd Century, and the marsh has been dubbed the Global Change Research Wetland, or GCReW. The expertise that GCReW scientists have in simulating the future brought National Museum of Natural History scientists here to mirror the past.

Rich Barclay and Scott Wing are paleobotanists at the National Museum of Natural History. Paleobotanists are the ones who stare at leaves in Jurassic Park and say, “Alan, these plants haven’t been seen since the Cretaceous Period,” as everyone else stares at brachiosauruses. Ancient plants are their bread and butter, and for Wing and Barclay, the bread is toasted and the butter melty. They study one of the warmest periods in the last 100 million years, the Paleocene-Eocene Thermal Maximum (PETM). During this period, global temperatures skyrocketed, increasing by 10-15 degrees Fahrenheit. By looking at plants that grew during this time, they hope to learn more about what Earth was like 55 million years ago.

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Large growth chambers being built around newly-planted ginkgo trees on the SERC campus (Credit: Rich Barclay)

Barclay, Wing, and colleagues have started an experiment on the Smithsonian Environmental Research Center’s (SERC) campus that grows ginkgo trees in varying carbon dioxide levels. They hope to study these trees and compare them to fossil specimens to learn about the past. Click to continue »

The Tiny Fish Awards!

Wednesday, July 5th, 2017

by Joe Dawson

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A sample of the diversity present within the cryptobenthic reef fishes. Figure from Goatley and Brandl 2017.

Go snorkeling on a coral reef, and you’ll have a hard time not being impressed by the abundance and variety of the fish there. But the fish most divers see make up less than half of the number (and less than half the species) of fish on the reef. Cryptobenthic reef fishes comprise the other half. These fish are small, usually less than 2 inches in length, and hide in coral habitats, either by appearance or by their behavior. Even scientists have been slow to start searching for them, but cryptobenthics are turning up in about every reef habitat where scientists have bothered to look! In the June 5 issue of Current Biology, SERC Scientist Simon Brandl and colleague Christopher Goatley of the University of New England published a quick guide to cryptobenthic reef fishes. Brandl thinks that these little fishes deserve more recognition, and we agree! Therefore, we’re happy to present these honorees with the following awards.

Coolest Camo

Runners Up: Frogfishes (Family Antennariidae), Scorpionfishes (Family Scorpaenidae)

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The painted frogfish, Antennarius pictus (Credit: John E. Randall/Hawaii Biological Survey, used under CC BY-NC 3.0)

Weird and tricky, frogfishes have plump, short bodies. They’re often covered in spines or even hair-like appendages and prefer to stay still, waiting and blending in, for prey to swim close enough that they can gulp them. The deep-sea dwelling anglerfish is one famous member of this group.

Scorpionfish are also sit-and-wait predators, using their feathery scales or skin flaps to look like rocks or coral, then pouncing on nearby prey. The most renowned member of this group is the lionfish. Click to continue »

Q&A: Ian Davidson, Aquatic Inquirer

Monday, June 26th, 2017

by Joe Dawson

ICD at Cork Harbor

Ian Davidson in Cork, Ireland (Credit: Ian Davidson)

 Ian Davidson is continuing his work at SERC in a new role: as principal investigator of his own lab. From diving under massive cargo ships to studying an invasive organism ugly enough to be nicknamed ‘rock vomit,’ Ian Davidson looks at how human activities affect marine ecosystems. This includes the methods by which humans transfer marine life around the world (mainly shipping), the effects of coastal development on nearshore environments, and management and policy with regard to marine invasions and organisms.

This is the third of three profiles about the young scientists leading SERC’s newest labs. Edited for clarity and space.

How did you get interested in your area of study?

I grew up in Cobh (pronounced, “Cove”), a small harbor town on the south coast of Ireland, so I had plenty of time in rock pools when I was young. My mother grew up a stone’s throw from the shoreline, right in front of the main shipping channel there, so we were always keeping an eye on the to-and-fro of the port. My dad worked in a shipyard until it closed down too, so I suppose the ingredients were there to pursue a career that heavily featured marine biology and shipping! Click to continue »

Q&A: Katrina Lohan, Marine Parasite Hunter

Friday, June 23rd, 2017

by Kristen Minogue

Katrina Lohan hiking in a forest

Katrina Lohan in New Zealand’s Abel Tasman National Park. (Credit: Chris Lohan)

Weird truth: There are more parasites on Earth than non-parasites. Katrina Lohan would know, having spent over a decade studying them. After five years with the Smithsonian Environmental Research Center’s Marine Invasions Lab, Lohan is now in charge of launching the center’s new Marine Disease Ecology Lab. In this Q&A, meet some of the weirdest parasites she’s encountered and learn how DNA is helping her unlock their secrets.

This is the second of three profiles about the young scientists heading SERC’s newest labs. Edited for brevity and clarity.

What do you find most fascinating about parasites?

I really like it when stories are complicated. And adding parasites certainly complicates any story. But I’m also intrigued by the David and Goliath aspect of it, that parasites are super small, [often] overlooked, and most people don’t even think about them in terms of what role they play in ecosystems or what they could possibly be doing. Most people would sort of shrug off—oh, they’re probably not really that important.  And yet, they’re extremely important. The more we learn about parasites, the more we realize that they control their hosts. They can actually completely change the behavior of their hosts. Click to continue »

The Environmental Cost of Shoreline Hardening

Wednesday, June 21st, 2017

New study shows hardened shorelines may mean fewer fish and crustaceans. 

by Ryan Greene

A split image with a wooden bulkhead on the left and a rocky riprap revetment on the right.

A new SERC study shows that both bulkheads (left) and riprap revetment (right) are associated with lower abundance of several species of fish and crustaceans in the Chesapeake Bay and the Delaware Coastal Bays. Credit: SERC

For decades, ecologists have suspected that hardened shorelines may impact the abundance fish, crabs, and other aquatic life. But now they have evidence that local effects of shoreline hardening add up to affect entire ecosystems. A new study by scientists at the Smithsonian Environmental Research Center (SERC) shows that more shoreline hardening means fewer fish and crustaceans in our waters.

Given the predictions for the coming years (i.e. rising seas and more of us living on the coast), this finding is a cause for concern. Many people will likely try to protect their land from flooding and erosion by armoring their shorelines with vertical retaining walls (bulkheads) or large rocks (riprap revetment). But as SERC researchers found in their new paper, published in Estuaries and Coasts, the impact of these hardened shorelines adds up.

Lead author and former SERC postdoc Matt Kornis likens shoreline hardening to littering. While each individual bit of trash isn’t a huge problem, the combined effect can be enormous. Kornis, now a biologist for the U.S. Fish & Wildlife Service, says the same is true of shoreline hardening. Each individual bulkhead or riprap revetment may not be catastrophic, but cumulatively they can contribute to shrunken populations of ecologically—and economically—important species like the blue crab.

“Shoreline hardening can cause loss of habitats important for young fish, like wetlands and submerged vegetation,” Kornis says. “That may be one reason we observed low abundance of many species in estuaries with a high proportion of hardened shoreline.” Click to continue »