Tag Archives: St. Joe Bay

Black mangrove propagules.

VIDEO- Mangroves and Cold, & Oyster Doctors Airs on WFSU

Rob Diaz de Villegas WFSU-TV

Wednesday, March 19 at 8 PM on WFSU-TV, catch the broadcast premiere of the new In the Grass, On the Reef documentary: Oyster Doctors.

Withered Black Mangrove

Although it was a relatively mild winter, one or two harsh cold snaps provided Randall an opportunity to test black mangrove survivorship in north Florida marshes, where it has become a more frequent resident.

Lately I’ve been preoccupied with wrapping up the National Science Foundation grant that funds a lot of what appears on this blog, and thinking about the future of the project.  The last major piece of funded content is our latest documentary, Oyster Doctors, chronicling four years of research conducted by Dr. Randall Hughes and Dr. David Kimbro.  On the one hand, the show is about learning how coastal ecosystems work.  And it’s about how the inner workings of salt marshes, oyster reefs, and seagrass beds provide people with jobs, clean water, and protection from erosion and storm surge.  But it’s as much about the ecologists as it is about the ecology.

Randall and David, and their graduate students- Tanya Rogers, Hanna Garland, and Althea Moore– are people who get inspired to pursue a line of research.  They get excited by an idea, like predators affecting prey more through fear than through their eating them.  They get excited about places.  David gets geeked out about predatory snails on Bay Mouth Bar.  Hanna falls in love with Apalachicola and wants to figure out its oyster problem.  Randall makes observations about things she sees in St. Joseph Bay marshes and it sets her on a path.  In one case, that path led her to the video above.

Randall’s interest in black mangroves has unfolded before our eyes on this blog, starting in 2010.  These trees have a range that ends to the south and east of here, yet here they were by her study sites.  To learn more, she started experiments.  Our Oyster Doctor premiere events on March 8 gave her a reason to come down from Massachusetts (she left the FSU Coastal & Marine Lab in January of 2013) and check on her mangrove experiments.  These experiments are growing away in the St. Joseph Bay State Buffer Preserve.  One of our premiere events was a walking tour of the Buffer and a visit to the experiment site.  One reason the trees have been spreading in northern Gulf marshes are the warmer winters we’d been having in recent years.  Recent cold snaps let Randall (and a group of interested parties) better see how certain sets of trees in her experiment might survive up here.  And so, as we finished the show, which has its section on the mangrove research, we went right back into the field and gained a little extra knowledge. Nature’s inner workings never stop unfolding.

Later that day, Randall joined Apalachicola Riverkeeper Dan Tonsmeire for an excursion within the Apalachicola River delta. Exploring the connection between freshwater bodies and coastal ecosystems has become a focus of this project since we started our EcoAdventures segments.

Later that day, Randall joined Apalachicola Riverkeeper Dan Tonsmeire for an excursion within the Apalachicola River delta. Exploring the connection between freshwater bodies and coastal ecosystems has become a focus of this project since we started our EcoAdventures segments.

In the coming months, we’ll get more posts detailing Randall and David’s findings in the studies we’ve been following.  And then… well, certainly more EcoAdventures.  Through those we can explore all of our area, connecting forests with swamps with rivers and back to the coasts, where this project was born.  As people signed up for the premiere and its associated events, we left a spot for people to tell us about their connection to our local wild spaces.  I’ll be looking those over as we move forward.  I love having a window into what all of you care about.  Likewise, this blog has a comments section!  Tell us what gets you excited about the outdoors, what you’d like to see more of, what’s not being covered?

Follow us on Twitter @wfsuIGOR

This material is based upon work supported by the National Science Foundation under Grant Number 1161194.  Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.

Coastal Roundup August 10th – August 17th, 2012

Rebecca Wilkerson WFSU-TV

Choctawhatchee Basin Alliance Volunteer Day – Oyster Reef Bagging
Oyster reefAugust 17th
Santa Rosa Beach, FL
(850) 200-4173
For more information and a list of volunteer opportunities visit the Choctawhatchee Basin Alliance volunteer page.

Treasure Hunt Scallop Drop
Bay scallop in St. Joe Bay seagrass bedAugust 17th- September 10th
St. Joseph Bay, FL
(850) 229-7800

16th Annual MBARA Kingfish Tournament
August 25th
Mexico Beach, FL
For more information visit the MBARA tournament page.

“Sopchoppy Stop” Eco-Heritage Tour
P1000534August 25th
Sopchoppy, FL
(850) 926-3376
For more information visit the Sopchoppy Stop tour page.

In the Kitchen

This week will mark the 100th birthday of Julia Child on August 15th. In celebration of the cooking legend, Marc Matsumoto uses Child’s Bouillabaisse to set the framework for a simple Seafood Stew using local ingredients. Learn more about his technique on the PBS Food Blog.

While we’re on the subject of local ingredients, check out how Gulf shrimp from Franklin County is used in this Buffalo Shrimp recipe.

On the East Coast

Near Dr. Hughes and Dr. Kimbro’s  St. Augustine research sites is the Fort Matanzas National monument. This National Park includes beach habitat that is crucial to several iconic Florida species. The National Park Service 2012 management plan has been drafted and some of the changes pose a risk to the wildlife here. The National Park Service will be hearing public input on the draft until August 24th. Visit this Audubon Florida news release for more information.

Clean Water Act

October will mark the 40th anniversary of the Clean Water Act. It is important to understand the importance of this piece of legislation, and to remember that there is still work that needs to be done. Visit this National Geographic News Watch article to read more about the Clean Water Act and its past, present, and future.

Apalachicola River

Apalachicola River at Bloody BluffOctober is also when the 2012 RiverTrek paddle is happening. This five-day  journey along the Apalachicola River helps raise awareness of the plight of the river system. RiverTrek also raises money for the Apalachicola Riverkeeper. For more information about RiverTrek , check out Doug Alderson’s Visit Tallahassee blog.

Summer Reading

If your summer reading was taken up by technical manuals, historical tales, or academic studies, you’re not alone. Although these aren’t the typical “beach books” we associate with summer lounging, many people use vacation time to catch up on the reading they’ve pushed aside throughout the year. Read more about which books are being packed for vacations on the NPR Books Blog.

In the Grass, On the Reef is funded by a grant from the National Science Foundation

Dude, where’s my water?

Rob Diaz de Villegas WFSU-TV

IGOR chip- human appreciation 150

St. Joe Bay is really jumping in the summer. People are everywhere; scalloping, fishing, kayaking and snorkeling. The people are mostly gone in the autumn, as they head back to work and school, and the weather is a little cooler. With less people to scare them off, you see more blue crabs, stingrays, and sharks swimming closer to the shore. It’s my favorite time of year to get footage there. When winter rolls around, the only people out on the water either have to be because they’re working (like Randall and her crew), or they’re just hardcore ecowarriors. It can make for difficult paddling in the winter (though this December is much milder than last year, when we shot this footage).

Super-low tide in St. Joe Bay.

The difficulty doesn’t so much stem from the cold, though it can get cold (especially for a native Floridian who thinks Massachusetts beach water is too chilly in July). The real challenge is the wind and the tides. It makes for a surreal landscape.  It’s mostly devoid of living animals, at least on the surface, but that north wind does push some interesting seagrass bed denizens onto the marsh with the seagrass wrack.

As I noted earlier, it has been milder this year.  Hopefully that holds for our next few EcoAdventure shoots, which include trips down the Wacissa and St. Marks rivers.  And I’ve already started planning some of next year’s shoots as well, so stay tuned!

Dan and Debbie VanVleet, who we interviewed in the video, are the proprietors of Happy Ours Kayak and Canoe Outfitter.
The music in the video was by Bruce H. McCosar.

A long time in the making

Dr. Randall Hughes FSU Coastal & Marine Lab

IGOR chip- biodiversity 150

As I mentioned in my last update, we have been working to set up a new marsh experiment in St. Joe Bay. The goal of the experiment is to see whether the genetic diversity of marsh cordgrass (Spartina alterniflora) affects how quickly or abundantly the plants grow, or influences the number of fiddler crabs, grasshoppers, snails, and other critters (like Ibis??) that call the plants home. But what is genetic diversity, exactly, and why do we think it may be important?


A flock of Ibis resting among our experimental marsh plots.

Spartina is a clonal plant, which means that a single “individual” or clone made up of many stems can dominate a large area (low diversity), or there can be lots of different individuals mixed together (high diversity). In our surveys of marshes in the northern Gulf of Mexico, we find that there can be as few as 1 and as many as 10 clones in an area of marsh about the size of a hula-hoop. You may notice that our experimental plots are about that same size, though we used irrigation tubing rather than actual hula-hoops (not as fun, but more practical and less expensive!). We’re testing whether the differences in genetic diversity (1 vs. 10 clones) that we see in natural marshes has any influence on the marsh community.

A single experimental plot of Spartina that is 1m in diameter.

But why genetic diversity? We know from experiments by other researchers that Spartina clones grown individually differ in height, how many stems they have, and other characteristics. These same plant traits affect the critters that live in and among the plants – for example, periwinkle snails preferentially climb on the tallest plants. Because different animals may be looking for different plant traits, then having greater diversity (genetic and trait) may lead to a greater number of animal species that live in that patch of marsh. Or, a single clone may be the “best”, leading to higher numbers of animals in lower diversity areas.


A view of the existing marsh behind our experiment.

As my title alludes, this experiment has taken a long time to come to fruition, in large part because it’s impossible to look at any 2 stems in a marsh and know for certain whether they’re the same individual or not. Unlike some clonal plants such as strawberries, where there are multiple berries connected by a single above-ground “runner”, Spartina has runners (aka, rhizomes) that connect stems of the same genetic individual under the ground, making it difficult to tell which stems are connected to which. We have 2 ways to get around this problem: (1) we use small snippets of DNA (analyzed in the lab) to tell clones apart, and (2) we start with single stems that we know are different clones and then grow them separately in the greenhouse until we have lots of stems of each different clone. It’s this latter part that has delayed this experiment – it has taken much tender loving care from Robyn over the last 2 years to get our Spartina clones to grow in the greenhouse to the point that we have enough of each clone (36 small flowerpots of each, to be exact) to plant in our experiment.


Emily and Robyn work to remove existing rhizome material from around the plot edges.

But plant we finally did! With lots of help from members of the Hughes and Kimbro labs, we got all the sand in the experimental plots sieved (to remove any existing root material) and all the plants in the ground the Thursday and Friday before Thanksgiving.


Team Hug-bro (Hughes and Kimbro) helping sieve sand!



Meagan and Randall get the easy job - planting the plants.

Now we get to wait and see (and take data) whether Spartina genetic diversity matters for the marsh plant or animal community. There won’t be any quick answers – the experiment will run for at least 2 years – but we’ll be sure to keep you up-to-date!

Randall’s research is funded by the National Science Foundation.

Tricks or Treats? And more on the effects of predators in marshes.

Dr. David Kimbro FSU Coastal & Marine Lab

IGOR chip_ predators_NCE 150Unlike most of the experiments that I’ve conducted up to this point in my career, the oyster experiment from this past summer does not contain a lot of data that can be analyzed quickly.

For example, predator effects on the survivorship of oysters can be quickly determined by simply counting the number of living as well as dead oysters and then by analyzing how survivorship changes across our 3 experimental treatments (i.e., cages with oysters only; cages with mudcrabs and oysters; cages with predators, mudcrabs, and oysters).  But this simple type of data tells us an incomplete story, because we are also interested in whether predators affected oyster filtration behavior and whether these behavioral effects led to differences in oyster traits (e.g., muscle mass) and ultimately the oyster’s influence on sediment characteristics.  If you recall, oyster filter-feeding and waste excretion can sometimes create sediment conditions that promote the removal of excess nitrogen from the system (i.e., denitrification)


As we are currently learning, getting the latter type of data after the experiment involves multiple time-consuming and tedious steps such as measuring the length and weight of each oyster, shucking it, scooping out and weighing the muscle tissue, drying the muscle tissue for 48 hours, and re-weighing the muscle tissue (read more about this process here).

After repeating all of these steps for nearly 4,000 individual oysters, we can subtract the wet and dry tissue masses to assess whether oysters were generally:

(a) all shell…“Yikes! Lot’s of predators around so I’ll devote all of my energy into thickening my shell”

(b) all meat…“Smells relaxing here, so why bother thickening my shell”

(c) or a mix of the two.

For the next two months, I will resemble a kid with a full Halloween bag of candy who cannot wait to look inside his bag to see whether it’s full of tricks (nonsensical data) or some tasty treats (nice clean and interesting data patterns)!  I’ll happily share the answer with you as soon as we get all the data in order.

Because of this delay, let’s explore some new research of mine that examined how predators affect prey traits in local marshes and why it matters.


There are two main ingredients to this story:

(a) tides (high versus low) dictate how often and how long predators like blue crabs visit marshes to feast on tasty prey.

(b) prey are not hapless victims; like you and me, they will avoid risky situations.

attach.msc1In Spartina alterniflora systems, periwinkle snails (prey) munch on dead plant material (detritus) lying on the ground or fungus growing on the Spartina leaves that hover over the ground.  Actually, according to Dr. B. Silliman at the University of Florida, these snails farm fungus by slicing open the Spartina leaves, which are then colonized by a fungal infection.  If snails fungal farm too much, then the plant will eventually become stressed and die.

So, I wondered if the fear of predators might control the intensity of this fungal farming and plant damage.

For instance, when the tide floods the marsh, snails race (pretty darn fast for a snail!) up plants to avoid the influx of hungry predators such as the blue crab.

After thinking about this image for a while, I wondered whether water full of predator cues might enhance fungal farming by causing the snail to remain away from the risky ground even during low tide.  Eventually, the snail would get hungry and need to eat, right?  Hence, my hypothesis about enhanced fungal farming due to predator cues.   I also wondered how much of this dynamic might depend on the schedule of the tide.

Before delving into how I answered these questions, you are probably wondering whether this nuance really matters in such a complicated world.  Fair enough, and so did I.

Addressing this doubt, I looked all around our coastline for any confirmatory signs and found that Spartina was less productive and had a lot more snail-farming scars along shorelines subjected to a diurnal tidal schedule (12 hours flood and 12 hours ebb each day) when compared to shorelines subjected to a mixed semidiurnal schedule (2 low tides interspersed among 2 high tides that are each 6 hours).  Even cooler, this pattern occurred despite there being equal numbers of snails and predators along both shorelines; obviously density or consumption effects are not driving this pattern.


Ok, with this observation, I felt more confident in carrying out a pretty crazy laboratory experiment to see if my hypothesis might provide an explanation.


Enter Bobby Henderson.  This skilled wizard constructed a system that allowed me to manipulate tides within tanks and therefore mimic natural marsh systems; well, at least more so than does a system of buckets that ignore the tides.


Within each row of tide (blue or red), I randomly assigned each tank a particular predator treatment.  These treatments allowed me to dictate not only whether predators were present but whether they could consume & frighten snails versus just frightening them:

-Spartina only

-Spartina and snails

-Spartina, snails, and crown conch (predator)

-Spartina, snails, blue crab (predator)

-Spartina, snails, crown conch and blue crab (multiple predators)

-Spartina, snails, cue of crown conch (non-lethal predator)

-Spartina, snails, cue of blue crab (non-lethal predator)

-Spartina, snails, cues of crown conch and blue crab (non-lethal multiple predators)

attach.msc6After a few weeks, I found out the following:

(1) Predators caused snails to ascend Spartina regardless of tide and predator identity.  In other words, any predator cue and tide did the job in terms of scaring the dickens out of snails.

(2) Regardless of tide, blue crabs ate a lot more snails than did the slow moving crown conch and together they ate even more.  This ain’t rocket science!

(3) In this refuge from the predators, snails in the diurnal tide wacked away at the marsh while snails in the mixed tide had no effect on the marsh.


Whoa…the tidal schedule totally dictated whether predator cues indirectly benefitted or harmed Spartina through their direct effects on snail predator-avoidance and farming behavior.  And, this matches the observations in nature… pretty cool story about how the same assemblage of predator and prey can dance to a different tune when put in a slightly different environment.  This study will soon be published in the journal Ecology.  But until its publication, you can check out a more formal summary of this study here.

If this sort of thing happens just along a relatively small portion of our coastline, I can’t wait to see what comes of our data from the oyster experiment, which was conducted over 1,000 km.

Till next time,


David’s research is funded by the National Science Foundation.

Paddling the Florida Circumnavigational Trail | Forgotten Coast

If you missed it on Dimensions, here is our video on the Florida Circumnavigational Saltwater Paddling Trail.  This segment runs from Port Saint Joe to the Saint Marks National Wildlife Refuge.  There are several camping options along the way; Doug Alderson (Of FDEP’s Office of Greenways and Trails) takes us to St. George Island State Park to look at some sites.

If you have an eco-adventure you’d like to share or have covered, leave a comment on our Ecotourism North Florida page.

Happy Ours kayaksFor more information on the trail, visit the trail web site.

The Path Less Paddled

Take a photo tour of the Forgotten Coast segment of the Florida Circumnavigational Saltwater Paddling Trail.  Watch a video on the trail on Wednesday, September 14 at 7:30 PM/ ET on WFSU-TV.

Rob Diaz de Villegas WFSU-TV

IGOR chip- human appreciation 150IGOR chip- habitat 150IGOR chip- gastronomy 150It all happened in about five minutes. The gull swooped down and grabbed a soft-shell blue crab about half its size, abandoned it to a swarm of small fish, whose activity may or may not have attracted a shark coming in from Apalachicola Bay.  I was standing at Sugar Hill, a beach campsite in the St. George Island State Park, the last campsite along the Forgotten Coast segment of the Florida Circumnavigational Saltwater Paddling Trail.  You can see this video on tomorrow’s dimensions.

(watch a video on the making of a blue crab molting its shell)

Were a kayaker to try to make the five or six day paddle from Cape San Blas to St. George Island, they would likely see a few of these little dramas play out.  As Doug Alderson (Paddling Trails Coordinator for the Florida Office of Greenways and Trails)  says in the piece, it’s one of the wildest stretches of the statewide trail.  That means it has a lot of nice scenery of coastal habitats.  Much more interesting, though, is that they are functioning habitats.

Predatory snails on Sugar Hill Beach at St. George Island State Park

Large predatory snails congregating on a tree stump at Sugar Hill camp site.

For instance, Doug loves to catch redfish when he camps on St. George; and they’re always there for him.  But why are these fish so abundant in Apalachicola Bay?  The answer is in those tasty oysters that put the name Apalachicola on the map.  Oyster reefs are a refuge for all kinds of animals like stone crabs, blue crabs, and various predatory snails and small fish.  It’s an all you can eat buffet for larger fish looking for those small fish and little mud crabs.  The action I described above happened by a seagrass bed not far offshore.  Those beds thrive in water that oysters filter clean, and so they provide another habitat for marine life in the bay.  I ate Apalachicola oysters for years without realizing just how much they give, and give, and give…

Rob and Debbie by kayak

Rob photographs small fish and crabs that Debbie scooped out of St. Joe Bay.

At the other end of the trail, In Saint Joseph Bay, we caught up with Dan and Debbie VanVleet of Happy Ours Kayak and Canoe Outpost.  When WFSU first started the In the Grass, On the Reef project, we rented our kayaks from Dan and Debbie.  Debbie’s been wanting to take us snorkeling for a while, to get some video of some of the critters living in seagrass beds in St. Joe Bay.  Kayaking over the shallow waters in the bay, you can see the turtlegrass from where you’re sitting, as well as rays, horseshoe crabs, and snails making their way about the sandy bottom.  To see the creatures living in the seagrass beds, you have to get out of the kayak.  This is where you have to be careful.

It is illegal to remove shells from St. Joseph BayWhen I say be careful, I’m not just talking about your safety, though you should shuffle your feet to alert stingrays that you’re coming, or if you kayak to St. Vincent Island, definitely stay out of the way of charging boars.  You also have to be careful with these habitats, and the marine life within them.  Dan and Debbie (and local law enforcement) are very big on people not taking seashells out of the bay.  Taking a bunch of whelks and crown conchs out of the bay means taking out critical predators, removing a top layer in the local food web.  And, as the sign implies, even a dead shell has a role to play (any hermit crab would agree).  It’s called the “leave no trace” approach, and there are tips on how to best accomplish this on the trail website.  There are also safety tips and maps.  If you’re attempting anything more than a day trip along this trail, it’s a pretty comprehensive resource.

Doug has put a lot of work into mapping the trail- it took three years- and assembling resources so that people could best enjoy it.  You can hear the love he has for paddling when he reads from his book, Wild Florida Waters.  You’ll hear a couple of passages in the show tomorrow.  Even hearing him read about paddling in a strong wind kind of gets me excited about going out again.  It reminds me of paddling to safety in St. Joe Bay after a sudden thunderstorm erupts, or paddling in December when the cold water numbed my hands.  It’s not as predicable a form of recreation as visiting a beach resort.  But it’s never boring.

Doug and Josh

Thanks to Doug (L) for talking to us, and Park Ranger Josh Hodson for driving us around St. George Island State Park.

Dan and Debbie from Happy Ours

Thanks to Debbie and Dan for taking us out.

Have fun out there.  And share your stories with us!  Click on the Ecotourism North Florida link above if you have an eco-adventure you’d like to see us cover.

Kayaking, anyone?

Rob Diaz de Villegas WFSU-TV

IGOR chip- human appreciation 150

Here’s a vacation idea for you.

If you had the time, didn’t mind camping for months on end, and were physically up to paddling fifteen hundred miles, you could paddle around the entire state of Florida using trails mapped out by Doug Alderson.  He coordinates the Florida Circumnavigational Paddling Trail for the Florida Department of Environmental Protection (Visit the trail’s web site).  You would pass by major urban centers like Tampa and Miami.  You would make your way through the entirety of the Florida keys.  And you would see a lot of amazing coastal habitats.

Ready to go?


The Forgotten Coast segment of the trail starts in St. Joseph Peninsula State Park.

I’m guessing the vast majority of people reading this are saying no, though we would certainly want to hear from you if you were doing this.  Luckily, the trail breaks down into twenty six segments, and over one hundred individual day trips.  The one I’m interested in is Segment 4: The Forgotten Coast.  It takes you through some of my favorite places.  St. Joseph Bay has clear water and lively seagrass beds and salt marshes.  Many of St. Vincent Island’s most interesting animals aren’t aquatic, but if you look over as you paddle past you might see wild hogs running or even one of those elusive red wolves (not likely, but it doesn’t hurt to look).  Once you pass there, you could choose to either go along St. George Island or stick to the mainland and pass by Apalachicola, where you can try to find a place to land your kayak while you pick up some oysters.

We’ll be kayaking part of this trail for September 14 episode, and talking to Mr. Alderson about it.  Have any of you done this?  Are any of you attempting this, or any section of it, any time in the next month?  We want to know.  We want to see your photos.  We want to watch your videos. Leave a comment below, with links to any videos or photos if you like.  If you’ll be out that way in the next couple of weeks, we may want to interview you.

Leave your comments!

And we want to keep hearing from you.  If you have any ideas for stories we might do related to coastal ecotourism, leave a comment on our Ecotourism North Florida page.


The End of an Era

Dr. Randall Hughes FSU Coastal & Marine Lab

Randall examines an experiment cage as Robyn looks on.

IGOR chip- biodiversity 150Calling a one year experiment an “era” is probably a bit of an over-statement, but the end of our snail field experiment definitely feels significant. Especially for Robyn, who has traveled to St. Joe Bay at least once a week for the past year to count snails and take other data. And also for the Webbs, who were kind enough to let us put cages up in the marsh right in front of their house and then proceed to show up to check on them at odd hours for the last year!  And finally for this blog, because the beginning of the snail experiment was the first thing we documented last summer when we started this project with WFSU.  It’s nice to come full circle.

So why, you may wonder, are we ending things now? Is it simply because one year is a nice round number? Not really, though there is some satisfaction in that. The actual reasons include:

(1) The experiment has now run long enough that if snails were going to have an effect on cordgrass, we should have seen it by now. (At least based on prior studies with these same species in GA.)
(2) In fact, we have seen an effect of periwinkle snails, and in some cages there are very few plants left alive for us to count! (And lots of zeros are generally not good when it comes to data analysis.)
(3) Perhaps the most important reason to end things now:  it’s become increasingly difficult in some cages to differentiate the cordgrass that we transplanted from the cordgrass that is growing there naturally. Being able to tell them apart is critical in order for our data to be accurate.
(4) The results of the experiment have been consistent over the last several months, which increases my confidence that they are “real” and not simply some fluke of timing or season.

And what are the results? As I mentioned above, snails can have a really dramatic effect on cordgrass, most noticeably when our experimental transplant is the only game in town (i.e., all the neighboring plants have been removed). And not surprisingly, cordgrass does just fine in the absence of snails and neighbors – they’re not competing with anyone or being eaten!


Snails also have a pretty strong effect on the experimental cordgrass transplant (compared to when no snails are present) when all of its neighbors are cordgrass.


Most interestingly, snails do not have a big effect on the experimental cordgrass transplant when some of the neighboring plants are needlerush.


This result is consistent with some of the patterns we’ve observed in natural marshes, where cordgrass growing with needlerush neighbors is taller and looks “healthier” than nearby cordgrass growing without needlerush.

Having decimated the plants in the cage, the snails move towards the tallest structure they can reach- a PVC pipe.

But why? Those snails are pretty smart. They generally prefer to climb on the tallest plant around, because it gives them a better refuge at high tide when their predators move into the marsh. (We’ve shown this refuge effect in the lab – fewer snails get eaten by blue crabs  in tanks with some tall plants  than in tanks with all short plants.) Needlerush is almost always taller than cordgrass in the marshes around here, so this preference for tall plants means that snails spend less time on cordgrass when needlerush is around. And finally, less time on cordgrass means less time grazing on cordgrass, so the cordgrass growing with needlerush experiences less grazing pressure.

These results – consumer (snail) effects on cordgrass are lower when cordgrass grows mixed with needlerush – are consistent with theory on the effect of diversity, even though in this case we’re only talking about a “diversity” of 2 plant species.  And they could be important in the recovery or restoration of marsh areas where snails are causing a large reduction in cordgrass biomass.

The one thing we still don’t know with certainty – how do the snails determine which plant is taller??

I guess that’s the beauty of this job, in that there are always more questions to answer.

Randall’s research is funded by the National Science Foundation.

The new documentary, In the Grass, On the Reef: Testing the Ecology of Fear had a segment on the snail experiment.  Watch the full program here.  You can also read Randall’s post from the beginning of the experiment, and watch a video, here.

We want to hear from you! Add your question or comment.

To Houston and Back: A story of a marine biologist and bugs

Emily Field FSU Coastal & Marine Lab

Emily holds a net that will soon be full of marsh bugs. Later, at the lab, she will identify the many insect species that live amongst fiddlers and periwinkles, species more often associated with the habitat.

IGOR chip- biodiversity 150

Several weeks ago, I went to Houston to meet Thomas Decker, a tech in Steve Pennings’ lab at the University of Houston. Thomas graciously offered up his time to help me with my insect identifications. I have absolutely zero background in entomology, the study of bugs and other creepy crawlies most people squirm about. So how did I end up spending hours puzzling through an identification book on insects, a book with so many unfamiliar terms that I was constantly flipping to the glossary and various diagrams? Silly me, I decided that I needed to include the terrestrial part of my salt marsh community. Which meant I have spent quite a bit of one-on-one time with a dichotomous key on insects. A dichotomous key is a “choose your own adventure” style guide to identification. Continue reading