Tag Archives: biodiversity

TulipMurex

Predator Diversity Loss and Bay Mouth Bar: The Next Stage

David and Randall’s NSF funded oyster study looks to understand how predators control oyster eating animals such as mud crabs and crown conchs. But this dynamic isn’t exclusive to oyster reefs. They are also investigating how predators might help maintain salt marshes and seagrass beds. In their seagrass bed studies, they have focused on a system loaded with predators: Bay Mouth Bar.
Tanya Rogers FSU Coastal & Marine Lab

Tanya RogersThe very first time I drove from Tallahassee to the FSU Coastal & Marine Lab I saw a black bear crossing the Crawfordville highway. No joke. This was in June of 2010, and I had just driven 5 days and 2800 miles from San Francisco to the Florida panhandle to take up my new job on the Gulf Coast. I had just finished college in Washington state, and I had never before been to the Southeast. What sort of wild place had I ended up in?

IGOR chip_ predators_NCE 150IGOR chip- biodiversity 150A very wild and unique one it turns out, and one I’ve come to know better working for the past few years as a research technician for Dr. David Kimbro in the fascinating coastal habitats of this region. Primarily I’ve been traipsing around oysters reefs across the state for the collaborative biogeographic oyster study (now drawing to a close), but for the past year or so I’ve also been managing our side project in the Bay Mouth Bar system, a sandbar and seagrass bed near the FSU Marine Lab. Bay Mouth Bar is a naturalist’s playground filled with surprises and an astonishing diversity of marine creatures that never ceases to amaze me. It is also a unique study system with an intriguing history out of which we can begin asking many interesting questions. This coming fall I’m excited to be starting as Dr. Kimbro’s Ph.D. student at Northeastern University, and for part of my dissertation I’ve decided to conduct some new experimental research this spring and summer out on Bay Mouth Bar.

Horse conch consuming a banded tulip snail on Bay Mouth Bar.

A horse conch in Tanya’s experiment consuming a banded tulip snail.

Bay Mouth Bar is known for its especially diverse assemblage of large predatory snails, which the ecologist Robert T. Paine conducted a study of in the late 1950′s. In 2010, we began surveying the snail community on the bar, interested in what changes might have occurred in the 50 years since Paine’s time, a period during which very little research had been done in this system. I began synthesizing some of the data we’ve gathered, as well as talking to some of the long-term residents of the area. So what has changed on Bay Mouth Bar since the 1950’s? A number of things in fact:

  • Of the 6 most common predatory snail species, 2 are no longer present: the true tulip and the murex snail.
  • The number of specialist snails (like the murex, which only eats clams) has declined relative to the number of generalist snails (those that eat a variety of prey, like the banded tulip).
  • There has been a drastic reduction in the overall area of the bar and changes in the coverage seagrass, specifically the loss of large meadows turtle grass (Thalassia testudinum).
  • Surface dwelling bivalves (e.g. scallops, cockles), once enormously abundant, are now very rare.
True Tulip and murex Snails (no longer found at Bay Mouth Bar)

The two main snail species no longer found at Bay Mouth Bar, true tulip (The larger snail on the left, eating a banded tulip) and murex (right). The true tulip was, along with the horse conch, a top predator of the ecosystem, while the murex is a specialist snail, eating only clams.

Why is this interesting? Worldwide, we know that species diversity is declining as a result of human activities, that specialists are being increasingly replaced by generalists, and that consumer and predator species often face a disproportionate risk of local extinction. So what are the consequences of realistic losses and changes to biodiversity? Is having a diversity of predators beneficial (e.g. both horse conchs and true tulips) to an ecosystem as a whole? Do some species matter more than others? And how do the effects of predators depend on the type of habitat they’re in, given that habitats (like seagrasses) are also changing in response to the environmental changes? These are some of the questions I’m hoping to address in Bay Mouth Bar system, in which we have documented historical changes in predator diversity.

Tethered community in Tanya's Bay Mouth Bar experiment

One of communities in Tanya’s experiment. At the center are top predators reflecting either the current assemblage (a horse conch alone) or the historic assemblage (the horse conch and true tulip).  The predators are tethered to posts and given enough line to reach the lower level predatory snails (murex, lightning whelks, banded tulips, and Busycon spiratum) on the outside.  Those snails have enough line to get out of the large predator’s reach and forage for food.

This past week, I set up an experiment featuring a menagerie of snails tethered in different assemblages across Bay Mouth Bar. Some assemblages mimic the current assemblage, whereas others mimic the assemblage found on the bar during Paine’s time. These historical assemblages include the snail species no longer found there, which I collected from other locations where they are still abundant. Some assemblages have top predators (e.g. horse conchs) whereas others do not. Some are in turtle grass, others are in shoal grass. We’ll see how, over the course of the summer, these different assemblages affect the prey community (clams, mussels, small snails) and other elements of seagrass ecosystem functioning.

Music in the piece by Donnie Drost.  Theme by Lydell Rawls.

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

 

This attractive gastropod, seen int he video above, is a busycon snail wrapped around an atlantic moon snail that it just happens to be eating.  Nature videos have have a cast of human, animal, and plant characters.

Video: Where the Land Meets the Sea

Episode 1: Where the Land Meets the Sea

Rob Diaz de Villegas WFSU-TV

This time around, everything is both familiar yet new.

On the new tiles, spat are glued on with a mixture used to repair boat hulls.

I recently went to Saint Augustine to document the second version of Dr. David Kimbro and Dr. Randall Hughes’ tile experiment.  The basic concept is this: attach a certain amount of oyster spat (larval oysters- basically little blobs in the process of growing and building shells) to tiles, leave them on or by oyster reefs and see how they grow, or if they are eaten.  I’ll let Randall and David explain the intricacies of the experiment when we post those videos in January.  Or, you could watch our coverage of that first experiment, conducted in the fall of 2010.  Watching that video and then watching our new videos on the experiment, you’ll notice that both the approach to the experiment and to the video coverage have evolved.  After the Kimbro lab spent so many long days scrambling to collect spat, The 2010 experiment didn’t succeed like they’d hoped.  Likewise, our communication of their research, and the importance of the ecology of intertidal ecosystems, didn’t quite succeed like I had hoped.   I like watching the old videos; I just don’t think they did what we wanted them to.  But you learn, and hopefully, you improve.

This time around, I was struck by how orderly everything was at the Whitney Lab as the oyster crew prepared their tiles.  No more scrambling out at low tide to collect oysters; they had hired someone to breed spat from oysters spanning the Eastern seaboard.  The current tile design and construction had been tested, and would withstand the elements.  Randall and David had learned lessons, and were efficiently implementing their new plan.  But what had I learned?

This attractive gastropod, seen in the video above, is a busycon snail wrapped around an atlantic moon snail that it just happens to be eating. Nature videos have a cast of human, animal, and plant characters.

Early last year, WFSU had a moment equivalent to that of the Hug-Bro labs’ realization that the glue on their initial tiles couldn’t withstand the waves at their sites.  The National Science Foundation had rejected our grant application to fund this project.  After a few months of following their studies and a couple dozen videos, a panel of reviewers let us know everything they thought we did wrong.  That was fun.

When Randall, David, Kim Kelling-Engstrom (WFSU’s Educational Services Director) and I decided to reapply for the grant, we needed a new narrative for what it was that we wanted to communicate.  What was our story?  If you watch our old videos, we’re very narrowly focused on experiments and field work.  There’s a lack of perspective on the impact of the ecosystems on our area, a lack of local color from the excellent locations we visit, and I kind of feel like we could have better captured what a day on a salt marsh or oyster reef was like.  The new application reflected more of the world around the reefs and marshes, and the people who need them.  If you’ve watched the video above, you may have figured that this time, our application was successful.

The red snapper being held by Ike Thomas, owner of My Way Seafood, was caught in 150 feet of water. Before reaching market size, younger snapper are one of many fish species that forage on oyster reefs.

I’m finding the new videos are more fun to put together.  We’re exploring the area more, talking to more people, and it’s easier to spot the animals we care about and get footage of them.  And with funding we have some extra staff helping on the blog and on shoots (like new associate producer Rebecca Wilkerson).  The upcoming videos are like the new tiles sitting in their cages off of Saint Augustine oyster reefs: they are the product of some hard won knowledge.  That experiment ends soon and they’ll see if they get the data they needed to meet their larger goals.  We, on the other hand, are just getting started, and we hope that you’ll keep joining us as we explore that area where the land meets the sea.

Over the next couple of weeks, we see the WFSU SciGirls visit the FSU Coastal & Marine Lab to learn about what Randall does: in the marsh, at the lab, and in front of the camera.  It gets a little messy.  In September, we go in the field with Randall and David onto oyster reefs and into seagrass beds and salt marshes.

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

Music in the piece was by Kokenovem and airtone.
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Video: Wildlife Watching at the St. Marks Refuge

Rob Diaz de Villegas WFSU-TV

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Andy Wraithmell by GFBWT kiosk

Andy Wraithmell at the Great Florida Birding and Wildlife Trail kiosk at the St. Marks Refuge.

I want to thank my co-adventurers for joining me on what turned out to be a remarkably wildlife filled day.  Andy Wraithmell from Florida Fish & Wildlife set our itinerary for the day and picked the best spots for the best time. I elaborated on those locations and timing considerations in last week’s post (with a map), which you can read here. It was great to meet Lou and Betsy Kellenberger, who have a real love for the place, and Alicia Wellman,who live-tweeted our day for Florida Fish & Wildlife.  Thanks also to my production assistant, Alex Saunders, for the great photos, and lastly to Refuge Manager Terry Peacock for talking to us.

In the video I alluded to there being too many places, activities, and programs in the Saint Marks National Wildlife Refuge for what ended up being an almost seven-minute piece. Over the years, we’ve covered some of those and I’ll point you to a couple of videos we’ve done along with some additional online resources.

The Whooping Crane Migration Program

The most famous birds associated with the Refuge are the ones you’re least likely to see on a visit.  I did a segment the first year they flew in.  You can watch that video here.  Their struggles this year were well documented, and while the Operation Migration folks ended up having to winter this year’s class in Alabama, one member of that original 2009 class paired off with one of the Chassahowitzka cranes from that year (half go to St. Marks, the other to Chassahowitzka National Wildlife Refuge) and flew to a cow pasture in Tallahassee’s Southwood neighborhood.  That means that they are learning their traditional migration paths, which is hopeful for their future.

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Hiking in the Cathedral of Palms.

The Florida National Scenic Trail

We just recently did a video on the Trail’s Aucilla Sinks segment. Previously, Florida Trail Association’s Kent Wimmer had taken us to two very special spots in the Refuge: Shepherd Spring and the Cathedral of Pines. You can see shots of those at the end of the video above. You can see that full video here.

The St. Marks Lighthouse

We don’t have a video uploaded on the lighthouse, but there is some news regarding it.  The Refuge is in the process of taking ownership of the lighthouse from the Coast Guard.  The plan is to open a bookstore on the ground floor, though the general public will still not be allowed to climb to the top and utilize what should be a sweet vantage point for photographers and (ahem) videographers.

Educational Programs

We see the new educational building and Terry Peacock talks about the number of students that participate in the Refuge’s education programs, but we don’t go into specifics. They offer 18 different programs and will work with teachers to meet their needs. Read more here.

The St. Marks National Wildlife Refuge Association

This group, led by their president, Betsy Kellenberger, coordinates volunteer efforts, classes, and field trips in the Refuge. Lou and Betsy, for instance, helped to build the Whooping Crane pens, which seems to me to be a neat way to be a part of that program. Visit the Association page here.

Music in the piece by unreal_dm and Andrea Pireddu.

Biodiversity and the Apalachicola: Why it’s Worth a Visit

Rob Diaz de Villegas WFSU-TV

Tune into WFSU-TV’s dimensions on Wednesday, February 15 at 7:30 PM/ ET to watch our paddling and wildlife watching EcoAdventure throughout the Apalachicola River system.

Zoom into the clusters of flags to see each site in more detail.
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This marsh island might be comprised of several genetically distinct cordgrass individuals, or just a few.

IGOR chip- human appreciation 150IGOR chip- biodiversity 150In composing and researching this post, I seem to have stumbled upon a diversity of biodiversity. In Randall Hughes’ salt marsh biodiversity study, you don’t always even physically see it.  Within a salt marsh, you might be looking at a variety of cordgrass individuals, or just one.  You wouldn’t know until you got the DNA results back from the lab.  That’s genetic diversity, the variation of genes within a species.  A little more obvious is the diversity of plant and animal life within a habitat: what other plants are mixed in with the cordgrass, what different predators are eating and terrorizing periwinkle snails, etc.  This species diversity is also crucial to a system’s health, and to the services it provides us. Continue reading

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?

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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.

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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.

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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.

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

 

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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.