Tag Archives: salt marsh

Just one more thing…

Dr. Randall Hughes FSU Coastal & Marine Lab
Setting up a tank experiment

Emily and Robyn setting up yet another tank experiment that I've dreamed up. (Thanks to Nancy Smith for the pic!)

IGOR chip- biodiversity 150Because of the big focus on oysters over the last month, it may seem as if we haven’t been doing anything “In the grass”. We’ve been busy, though, trying to squeeze in a few additional surveys and experiments in November before it gets cold enough that the animals stop eating (or eating very much, I should say) and the plants stop growing. For a while there, I was coming up with so many end of season ideas that I’m pretty sure my crew hated to see me coming!  We just did finish up before the winter weather arrived (early) in December. (More on what it’s like working in this cold weather in future posts.)

We actually missed the opportunity to do one of our planned studies involving grasshoppers – there was a cold snap two nights before we went in the field to get the hoppers, and they were nowhere to be found.   Those data will have to wait until next spring when the grasshoppers turn up again!

We’ve had better luck with two other projects –

1. Do snails prefer to climb on cordgrass reproductive stems?

More snails climbing on cordgrass reproductive stems

Snails climbing on cordgrass reproductive stems in the field.

Spartina reproductive shoot

A tasty snack for a periwinkle snail?

I’ve mentioned before on the blog that we noticed lots of snails climbing on cordgrass reproductive stems this fall. In collaboration with David and his team, we visited marsh sites along the Panhandle to see if our observations would be supported with rigorously collected data. So far, so good!


The trusty tank set-up at FSUCML.

We also started a series of experiments in our trusty tanks at the FSU marine lab to tease apart why snails may have this preference: Do the snails simply like that the reproductive stems are taller than regular stems? Or do the reproductive stems “taste” better because of greater nutrient content? Does it matter if predators are present or not? The preliminary results suggest that they like the reproductive stems, regardless of whether they are taller or not. In January, we’ll head into the lab to do the tests for nutrient content that should help us to tease apart why that may be.

2. Does needlerush provide a better predation refuge than cordgrass?

A patch of needlerush surrounded by cordgrass

Needlerush (center patch) is typically much taller than cordgrass (surrounding area) in St. Joe Bay

Last fall I did a tank experiment to look at whether snails prefer to climb on another marsh plant species, needlerush (Juncus roemerianus), and whether this preference increased snail survival when predators were around. The results were interesting, but as usual, the first round of the experiment created additional questions that required more work. In November we started a similar experiment, again in the tanks at the marine lab, looking at snail climbing behavior on needlerush and cordgrass in the presence and absence of the snail’s nemesis, the blue crab.

Needlerush is naturally taller than cordgrass, so to test if this difference in height can explain snail behavior, we “experimentally manipulated” (in other words, used scissors to cut the needlerush down to a shorter height) needlerush height: some tanks have naturally tall needlerush, some have needlerush that is on average the same height as the cordgrass, and some have needlerush that is shorter than the cordgrass. Add a blue crab to half of the tanks, and voilà, the experiment is underway!

blue crabIt’s a bit ironic that each of the experiments we recently finished converged on a similar idea – snails appear to prefer to climb on taller plants. Considering that the taller the plant, the farther they can climb away from predators in the water, it makes sense. The true question is to figure out whether and why it matters that the snails do this. If they climb on reproductive stems, are fewer cordgrass seeds produced? What will that mean for next year’s crop of cordgrass? Also, if snails spend a lot of time hanging out on needlerush to avoid predators, does that mean they don’t eat as much cordgrass? Knowing things as seemingly arcane as which plant a snail prefers to climb on can help us predict and manage the overall abundance and productivity of cordgrass, and the salt marsh in general. And of course, the field work and experiments are fun! Especially when you get to wrestle with blue crabs…

Here are some photos of periwinkle snails in Randall’s latest tank experiments:

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

Writing about a bygone era of fishing.

Mike Plummer WFSU-TV

IGOR chip- employment 150A few weeks ago we posted a video of a blue crab molting, and about the blue crab reproductive cycle.  The man narrating the video was Leo Lovel.  That video was an offshoot of a segment for WFSU-TV’s dimensions program, which we present here.  As a commercial fisherman and restauranteur, many of the species he makes his living off of are residents of Salt Marsh and Oyster Reef habitats.


Clay (L) and Leo (R) Lovel outside of their business, the Spring Creek Restaurant.

I heard about Leo Lovel from Rick Ott, a friend of mine who owns a recording studio in Sopchoppy, FL.   Rick was working on a project to record Leo’s books, The Spring Creek Chronicles 1 & 2, to audio files for books on tape or CD.   Rick thought I might be interested in Leo’s short stories about his fishing and hunting experiences around the big bend, dating back to his childhood, so he gave me a copy of the first book. I read some of the stories and then arranged to meet Leo to talk about the books.   At that meeting is where he told me about his idea to publish the All Florida Reader.   Now, Leo’s day job is owner of a restaurant called Spring Creek Restaurant.   It’s a family run business and the Lovel’s have cultivated a very loyal following throughout the southeast over the past 30+ years.   They either catch the seafood themselves or they buy it fresh, only from local fishermen.   It’s a pretty time consuming way to stock a seafood restaurant menu, but it’s the only way Leo Lovel will serve you a meal.

Back in the 90’s, Leo was also a commercial fisherman who was on the front line of the Florida net ban battle.   Although it doesn’t seem like such a long time ago, that era is quietly passing into Florida’s history as those old-timers pass on.   And that’s the unusual value I found in the stories that Leo took the time to put down on paper… these are first hand personal accounts of a specific area and people over a long period of time.   But Leo took his book project a step further.   He turned it into a tool in his personal attempt to help motivate local school kids to “want” to learn to read and write.  That’s the All Florida Reader and I think that speaks volumes about Leo Lovel.


Leo's marina at Spring Creek Restaurant. Into here will drift boats carrying what will become dishes in the restaurant.

Comments below:

Did You Say Mangroves?

Dr. Randall Hughes FSU Coastal & Marine Lab

Ed Proffitt and Randall Hughes by a black mangrove

Ed Proffitt with Randall Hughes. If global climate trends continue, mangroves may start to overtake the salt marsh ecosystem along the Gulf coast. What will these new habitats look like?

IGOR chip- biodiversity 150A few weeks ago, Dr. Ed Proffitt from Florida Atlantic University visited FSUCML to give a seminar here and on campus. Ed and I have collaborated on several proposals, so we used the visit as an opportunity to get out in the field and toss around some new ideas.

Ed has done some really interesting work on the interactions between mangroves and salt marsh plants in Tampa Bay and the Indian River Lagoon, and he wanted to see some mangroves in this area. I recalled having seen a few young red mangroves last year at some of our sites, but none of them survived this past winter (which is why we generally don’t find them around here – they can’t withstand the cold temperatures that we get every few years). However, black mangroves do extend into this portion of the Gulf, and I knew of a place where we may find one or two small ones to look at.


Black mangrove (Avicennia) growing in St. Joe Bay

To my surprise, we found a lot more than one or two! And although they are small (think small shrub, rather than tree), some of them, such as the one shown here, had aerial roots extending out 14-15m, suggesting that they have been around at least 5-10 years (by our best guess).

black mangrove flower

Avicennia flower. These mangroves are insect-pollinated, and we saw lots of bees buzzing around.


Avicennia propagules growing on the maternal tree.

Also, most of the larger ones had both flowers and propagules (seedlings that are retained on the tree) on them.


Avicennia propagule that has dropped to the ground and started to take root.

As we looked around, we noticed more and more small mangroves in the marsh – probably the seedlings from some of the nearby larger trees – and we even found some of this year’s propagules that were starting to root in the sediment.

As I mentioned, black mangroves are known to grow in the Panhandle and west into Louisiana and Texas, so it really isn’t that surprising that we found them in St. Joe Bay. What is surprising, at least to me, is that they are as abundant as they are in a site where I previously thought there were only a few. Where else may they be in the bay? And are they increasing in abundance each year? What impact do they have on the marsh plants and animals? The questions abound. With our curiosity and Ed’s insight and experience, we are now starting to pursue the answers.

Randall’s research is funded by the National Science Foundation.
We appreciate your input!  You can leave your comment below.

The search for patterns

Dr. Randall Hughes FSU Coastal & Marine Lab

IGOR chip- biodiversity 150The end of summer is a good time to pause and think about any general patterns that emerge from observations over the course of the last year(s). Sometimes it is easy to get swept up in the minutiae of individual projects and forget about the big picture. Of course, these patterns aren’t definitive (i.e., don’t quote me on this!), but they can be useful to think about, particularly when considering future avenues of research.


Marsh island in St. Joe Bay viewed from the waterand marshes on the edge of the mainland.

So what sort of patterns can I describe to you after two summers in the marshes of St. Joe Bay? One that doesn’t take a PhD to recognize is that there are two distinct types of marshes that we sample: marsh islands and marshes on the edge of the mainland.

But aside from the obvious fact that one is an island and the other is not, there are some additional interesting differences:

1. The slope of marsh islands is typically greater than mainland marshes, so that you move quickly from plants that can tolerate frequent flooding (cordgrass) to plants that are more “terrestrial” (pickleweed, saltwort, etc.). On islands this transition can occur within a few steps of the water’s edge, whereas mainland marshes typically have a large area (I like to think of it as a football field) dominated by cordgrass.


Elevation on islands changes rapidly compared to the mainland. Even slight differences in height can influence plant communities.


Sampling a mainland marsh in St. Joe Bay.

2. Marsh islands tend to have fewer periwinkle snails than mainland sites, although they are certainly present.


Abundant snails in a mainland marsh.

My guess is that the snail predators (blue crabs, crown conchs) that lurk just at the water’s edge have greater access to snails on the islands at high tide, because they can move in from all sides of the island. In contrast, the predators near mainland sites have only one point of entry into the marsh.

blue crab

Blue crab lurking in the seagrass at the edge of the marsh during low tide.


Crown conch foraging for snails in a lab experiment.

3. Perhaps not surprisingly given that they are surrounded by water, the marsh islands typically have fewer grasshoppers jumping around. We’ve also had far fewer snake encounters on islands, which I consider a good thing. Probably because land-based predators such as snakes, raccoons, etc., are less frequent on islands, we also observe greater numbers of nesting birds on the islands than at mainland sites.

4. One clear difference that I can’t explain but hope to examine in the future is that cordgrass plants collected from the islands (which can only be done with a special permit from the Department of Environmental Protection) survive better in our greenhouse at the lab than those from mainlands. It may simply be the growing conditions, or island plants may be hardier overall. Stay tuned.

As we continue to process, enter, and analyze data, there should be additional trends emerging. And we’ll likely find out that some of the patterns we think we see don’t hold up to the test of actual data. And so goes the process of science!

Randall’s research is funded by the National Science Foundation.
We want to hear from you! Add your question or comment.

The Making of a Softshell Crab

Rob Diaz de Villegas WFSU-TV

IGOR chip- habitat 150To clarify, we are looking at the biological process through which a blue crab molts its shell, not recipes (feel free though, to share your favorites in the comments area).  I have to admit that before I started this project, I had thought that softshell crabs were a specific species, or group of species.  Of course, such a species wouldn’t survive very well in the wild. Continue reading

Autumn in the marsh

Dr. Randall Hughes FSU Coastal & Marine Lab

Marsh periwinkles climbing on a cordgrass reproductive stem

A cordgrass reproductive stem stands above the surrounding plants.

IGOR chip- biodiversity 150 One doesn’t need to look at a calendar to realize that fall is upon us – recent cool mornings are a welcome sign. The marsh is also showing signs of change, with cordgrass flowering shoots springing up everywhere.

These stems are quite noticeable – they are taller than non-reproductive plants, and they have a “feathery” appearance due to the reproductive structures at the tops of the stems.

As I’ve mentioned before, cordgrass is one of those plants (like strawberries) that can spread by underground rhizomes, putting up new stems along the way. Alternatively, it can reproduce the “traditional” way, with reproductive stems that broadcast and receive pollen via the wind, ultimately producing seeds that fall to the sediment, get buried, and then germinate to produce new seedlings. Though conventional wisdom is that most new cordgrass stems are produced vegetatively by spreading rhizomes, it’s clear at our sites that these plants are investing a lot of energy in the other form of reproduction! Continue reading

A walk “in the grass”

Rob Diaz de Villegas WFSU-TV


Last week we had a post on what it was like on an oyster reef, the idea being that many people have never really seen one.  Continuing with that theme, I thought it might be interesting to take a closer look into a salt marsh.  This is a trickier proposition because, well, what is a typical salt marsh?  Some of them grow in muddy waters next to oyster reefs, or they can be found along beaches, in wide expanses or in small islands just off the coast.  I’ll keep today’s imaginary journey confined to marshes in St. Joseph Bay, where Randall Hughes conducts her biodiversity study- that is what I am most familiar with.

Continue reading

Operation Noah’s Ark

Rob Diaz de Villegas WFSU-TV

The video above is from our dimensions program. It dovetails nicely with what we care about on this site, which is the ecology of Florida’s Forgotten Coast, in this case salt marshes.  The idea is that, when looking to minimize potential oil damage to our coast, you start with its smallest building blocks.  Operation Noah’s Ark, based out of the Gulf Specimen Marine Lab in Panacea, is collecting a lot of little critters that live in places like salt marshes. The fiddler crab helps maintain the marsh with its burrows, which bring oxygen to cordgrass roots.  In that grass, juvenile mullet find shelter, as do blue crabs and juvenile pinfish.  The Kemps-Ridley Sea Turtle eats those blue crabs, and those pinfish will mature and swim out into the gulf to be eaten by gag grouper.  You can see how one species becoming compromised can have a cascading effect throughout the Gulf.
Continue reading

Is it over?

Dr. Randall Hughes FSU Coastal & Marine Lab

IGOR chip- biodiversity 150Since my last post, oil has stopped spewing from the Deepwater Horizon well, a very welcome development in what has been a long and grim story. Although it is tempting to feel that we are out of the woods, all one needs to do is consider the amount of oil that has entered the Gulf to realize that it will be a long time before we fully understand the ecological impacts of this disaster, much less fully recover from it.

That said, the probability that the marshes I study in St. Joseph Bay and Apalachee Bay are going to be directly impacted by oil has declined dramatically. You may wonder, were our efforts to collect “pre-oil” data wasted? The answer is no, for a number of reasons:

Continue reading

Eating contest: grasshoppers vs. snails

Dr. Randall Hughes FSU Coastal & Marine Lab

IGOR chip- biodiversity 150One of the really interesting aspects of the marsh community is that it is a mix of sea-based and land-based critters. At low tide, insects and rodents move in, whereas at high tide, snails, fish, and crabs dominate. The 2 most common plant grazers at our sites illustrate this dichotomy :

one is a land-based grasshopper(Dicromorpha elegans),


and the other is a sea-based snail (Littoraria irrorata).


In addition to being very abundant in our sites, the grasshoppers and snails leave distinctive grazing marks that alert us to their activity. Grasshoppers tend to chew large pieces out of the margin of the leaves, often resulting in the removal of large portions of the upper leaves. Snails, on the other hand, create razor-blade like incisions in the middle of the leaf:

grasshopper grazing 2

spartina with grasshopper grazing damage

Snail grazing scar

periwinkle grazing scars on spartina

We are interested in the potential for interactions between these 2 consumers, because they occur together in abundance at several of our sites. A preliminary experiment last summer suggested that snails somehow deter grasshopper feeding, even though neither animal can directly harm the other. (In fact, as you can see from the video, sometimes the grasshoppers even hang out on the snails’ backs!) However, it is possible that snails leave a “slime” trail that the grasshoppers don’t like, or perhaps snail grazing causes the plants to produce chemicals that make it less likely that grasshoppers will eat them.


To find out more, we are repeating the same experiment (with some minor modifications) to look more closely at how much snails and grasshoppers eat when they are alone versus how much they eat when they are together. Because it is difficult to make grasshoppers stay where you want them, we are doing the experiment in mesh cages inside “mesocosms” (science-speak for large buckets) at the FSU Coastal and Marine Lab.

The mesocosms are set up to mimic the natural tidal cycle, with both high and low tides on a regular basis. We measured the height and number of stems of all the plants in each mesocosm at the start of the experiment, and we’ll take these same data at the end of a couple of weeks to see which species has the largest effect, and whether their combined effects are different from what we expect based on what they eat alone.

As an aside, this experiment is a good example of one of my ecologist’s rules of thumb: you can never do an experiment just once. There are certainly exceptions to this rule. (For example, when you have lots of experience with the animals you are experimenting with, when the experiment is just too large to repeat, or when the experiment relies on something you can’t manipulate, such as an oil spill.) However, I find that it generally takes one go-around to work out the kinks, figure out the relevant time frame, and discover unanticipated results. Then I can be much more confident the second time around that the patterns I am seeing are real!

The music in the piece was by Ric Edmiston.  We are always looking for local musicians to score our videos.  If you are interested and already have some music recorded, we would love your submission.

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

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