Donn Shilling and Eldridge Wynn look over a research field
of cogongrass, which has become a problem for cattle ranchers.
Cogongrass is one of our larger invasive species here in the Panhandle, and spring is a good time to detect and treat it. If you know or suspect your property may have cogongrass, spring is the best time to hunt it down and locate the spots and infested areas. It is also a great time to patrol your property boundaries as well to see if you have any that may be coming onto your property from a neighbor or right of way. Cogongrass seems to love fencerows and right of ways as it spreads easily on equipment through its tough rhizomes. One of the best ways to prevent large infestations from taking over portions of your property and creating a significant control cost is to catch it early. The key to this is to identify and mark small spots before they expand; and then follow up with herbicide treatment once to twice a year. Spring is an excellent time to go and scout for cogongrass and get a jump on this invasive for several reasons.
A relatively new patch of cogongrass recently found in Washington County.
Photo Credit: Mark Mauldin
One feature of cogongrass that is very distinctive is the seed head. In spring cogongrass flowers and puts up a cottony white seed head. These seed heads look like an elongated fluffy white tuft on a tall stalk. Once you have seen them for the first time you will instantly recognize this invasive grass. If cogongrass has been mowed, it can sometimes be hard to spot especially in a pasture. In spring the seed heads will quickly draw your attention to an area infested with this grass. It is very distinctive, and you do not see other grasses with this type of seed head the same time of year.
Other distinguishing features of cogongrass include a bright green color sometimes with red edges. In the spring the new growth of cogongrass is very prominent and stands out due to its bright color and usually faster growth compared to other grasses. The midrib of the grass blade is also usually offset to one side, another identifying feature. If you have a shovel handy you can dig up a small amount and you will notice thick rhizomes with sharp pointed tips. Once you learn to identify cogongrass and know what you are looking for; you can go out on your spring cogongrass patrol to identify any areas of infestation.
Cogongrass shown here with seedheads – more typically seen in the spring. If you suspect you have cogongrass in or around your food plots please consult your UF/IFAS Extension Agent how control options.
Photo credit: Mark Mauldin
Once you have identified an infestation you need to do three things: mark the impacted area with a flag or other noticeable method, record the location (by description or GPS), and develop a treatment plan. Marking and recording the location of cogongrass infestations, especially a small spot that is new, is critical to the success of control efforts. Cogongrass is tough and requires multiple treatments with herbicide to effectively control it and hopefully eliminate the infestation. This means you need to know where a patch is, be able to relocate and monitor it, and consistently treat the same spot to ensure you achieved complete control. Cogongrass control is easier when the spot is small and has not become well established. With small spots it can be difficult to locate the spot again the next year, especially after a round of herbicide treatment, so good marking combined with a GPS location or description is essential. Once you have gone back to a spot several years and the spot has not come back after treatment; you can consider the spot controlled. If you stop treatment and monitoring before cogongrass has been controlled for several years, the infestation will return from remaining rhizomes and spread all over again.
Consistent treatment with effective herbicides is the best way to ensure cogongrass is controlled on your property. If you locate some while scouting this spring be prepared to start a treatment program. Cogongrass responds to herbicides with the active ingredients glyphosate or imazapyr. These can be used alone or in combination. The spring and fall are the two treatment windows that are most effective. If you treat in the early spring when new growth is vulnerable you can sometimes prevent seed heads from maturing. You can also get some control that can help prevent heavy growth over the summer, which can be an advantage if you have to mow or maintain the area. Spring treatment is usually best accomplished with glyphosate alone, imazapyr alone or a mixture of both can be used.
Once we progress into summer, treatments with herbicide will mostly top kill the grass and do not provide effective control. Treatment in the fall with imazapyr alone or in combination is the most effective treatment method. If you identify infestations in the spring you can mark them and come back in the fall to get the most bang for your buck with treatments. You can apply a spring and fall treatment in one year if you want to accomplish some control in the spring, but this method is not necessarily more effective than the fall treatment alone. When using imazapyr herbicide you should be aware that this is soil active and has the potential to damage surrounding vegetation and hardwood trees that are in and near the treatment area. Pines are tolerant of imazapyr but can be damaged if high rates are used, and longleaf pine is more sensitive than others. When treating cogongrass with imazapyr be aware that damage to other vegetation could occur. If the cogongrass is in an area with hardwood trees or other sensitive vegetation glyphosate alone is a good alternative herbicide treatment. When using any herbicide be sure to read and follow the label correctly, follow all label directions, and wear proper protective equipment. There are several IFAS EDIS publications on cogongrass control which provide more detailed information: for control in pasture areas follow this link SS-AGR-52/WG202: Cogongrass (Imperata cylindrica) Biology, Ecology, and Management in Florida Grazing Lands (ufl.edu) and for control in forested areas follow this link FR342/FR411: Biology and Control of Cogongrass (Imperata cylindrica) in Southern Forests (ufl.edu) . If you identify cogongrass on your property these publications will help you develop a treatment plan to control it. Early detection and treatment when infestations are small is key to getting this nasty invasive under control. Take advantage of this spring to identify, mark, and treat any cogongrass that may be getting a foothold on your property before it becomes a major infestation.
Most of us in the Florida panhandle realize how important seagrasses are to the ecology of our estuaries. Not only do they provide habitat for commercially important finfish and shellfish, but they also help trap sediments, remove nitrogen from the system, and slow coastal erosion. But seagrasses throughout Florida have suffered over the last 50-60 years from environmental stressors created by humans. There has been a large effort by local municipalities to reduce these stressors, and surveys indicate that these have been successful in many locations, but there is more to do – and there are things you can do to help.
Reduce Stormwater Run-off
Stormwater run-off may be the number one problem our seagrass beds are facing. With the increased development along the panhandle, there is a need to move stormwater off properties and roads to reduce flooding of such. Older communities may still have historic drain systems where rainwater is directed into gutters, which lead to drainpipes that discharge directly into the estuary. This rainwater is freshwater and can lower the salinity in seagrass beds near the discharge to levels the seagrasses cannot tolerate, thus killing them. This stormwater also includes sediments from the neighborhood and businesses that can bury grass near the discharge site and cloud the water over much of the system to levels where needed sunlight cannot reach the grasses. Again, killing the grass.
Most would say that this is an issue for the county or city to address. They should be redesigning their stormwater drainage to reduce this problem. And many municipalities have, but there are things the private homeowner or business can do as well.
One thing is to modify your property so that the majority of the rainwater falling on it remains there and does not run off. Much of the rainwater falling on your property falls on impervious surfaces and “stands” creating flooding issues. You can choose to use pervious surfaces instead. For larger businesses, you might consider a green roof. These are roofs that literally grow plants and the rainwater will irrigate these systems with less running into the street. There is a green roof at the Escambia County Central Office Complex building in Pensacola. To learn more about this project, or visit it, contact Carrie Stevenson at the Escambia County Extension Office.
The green roof on top of the Escambia County Central Office Complex in Pensacola.
For those buildings that cannot support a green roof, you can install gutters and a rain barrel system. This moves rainwater into a barrel (or series of barrels) which can then lead to an irrigation system for your lawn or garden. All of which reduces the amount entering the streets.
rain barrels can be used to capture rainwater and avoid run-off.
Finally, you can use pervious materials for your sidewalks, driveways, and patios. There are a number of different products that provide strength for your use but allow much of the rainwater to percolate into the groundwater, thus recharging the groundwater (our source of drinking water) and reducing what reaches the street.
Plant Living Shorelines
Coastal erosion is an issue for many who live along our waterfronts. The historic method of dealing with it is to build a seawall, or some other hardened structure. These structures enhance the wave energy near the shoreline by refracting waves back towards open water where they meet incoming waves increasing the net energy of the system. Something seagrasses do not like. There are many studies showing that when seawalls are built, the nearby seagrass begins to retreat. This increased energy also begins to undermine the wall, which eventually begins to lean seaward and collapse. Placement and maintenance of these hardened structures can be expensive.
FDEP planting a living shoreline on Bayou Texar in Pensacola.
Photo: FDEP
Another option is a softer structure – plants. The shorelines of many of our estuaries once held large areas of salt marsh which provide habitat for fish and wildlife, reduce erosion, and actually remove sediments (and now pollutants) from upland run-off. But when humans moved to the shorelines, these were replaced by turf lawns and, eventually, seawalls. Returning these to living shorelines can help reduce erosion and the negative impacts of seawalls on seagrasses. Actually, several living shoreline projects enhanced seagrasses in the areas near the projects. Not all shorelines along our estuaries historically supported salt marshes, and your location may not either. It is recommended that you have your shoreline assessed by a consultant, or a county extension agent, to determine whether a living shoreline will work for you. But if it works, we encourage you to consider planting one. In some cases, they can be planted in front of existing seawalls as well.
Avoid Prop Scarring While Boating
Seagrasses are true grasses and posses the same things our lawn grasses have – roots, stems, leaves, and even small flowers – but they exist underwater. Like many forms of lawn grass, the roots and stems are below ground forming what we call “runners” extending horizontally across the landscape. If a boat propeller cuts through them form a trench it causes a real problem. The stems and roots only grow horizontally and, if there is a trench, they cannot grow across – not until the trench fills in with sediment, which could be a decade in some cases. Thus “prop scars” can be detrimental to seagrass meadows creating fragmentation and reducing the area in which the grasses exist. Aerial photos show that the prop scarring issue is a real problem in many parts of Florida, including the panhandle.
The scarring of seagrass but a propeller. These can remain “open wounds” for years.
Photo: Rick O’Connor.
The answer…
When heading towards shore and shallow water, raise your motor. If you need to reach the beach you can drift, pole, or paddle to do so. This not only protects the grass, it protects your propeller – and new ones can be quite expensive.
If Florida residents (and boating visitors) adopt some of these management practices, we can help protect the seagrasses we have and maybe, increase the area of coverage naturally. All will be good.
If you have any questions concerning local seagrasses, contact your local Extension Office.
In Part 5 of this series, we looked at a group of invertebrates that few people see, and no one is looking for – worms. But in this article, we will be looking at a group that seagrass explorers see frequently and some, like the bay scallop, we are actually looking for – these are the mollusks.
With over 80,000 species, mollusk are one of the more successful groups of animals on the planet. Most fall into the group we call “seashells” and shell collection has been popular for centuries. There is an amazing diversity of shapes, sizes, and colors with the snail and clam shells found in coastal areas worldwide. As snorkelers explore the seagrass beds it is hard to miss the many varieties that exist there.
Seashells have been collected by humans for centuries.
Photo: Florida Sea Grant
One group are the snails. These typically have a single shell that is coiled either to the right or left around a columella. Some are long and thin with a extended shell covering their siphon (a tube used by the animal to draw water into the body for breathing). Others are more round and ball-shaped. Each has an opening known as the aperture where the animal can extend its large fleshy foot and crawl across the bottom of the bay. They can also extend their head which has an active brain and eyes. Snails lack teeth as we know them, but many do have a single tooth-like structure called a radula embedded in their tongue. They can use this radula to scrape algae off of rocks, shells, and even grass blades. Others will use it as a drill and literally drill into other mollusk shells to feed on the soft flesh beneath.
In the Pensacola area, the crown conch (XXX) is one of the more common snails found in the grasses. This is a predator moving throughout the meadow seeking prey they can capture and consume. Lighting whelks, tulip shells, and horse conchs are other large snails that can be found here. You can often find their egg cases wrapped around grass blades. These look like long chains, or clusters, of disks, or tubes, that feel like plastic but are filled with hundreds of developing offspring.
The white spines along the whorl give this snail its common name – crown conch.
Photo: Rick O’Connor
A close cousin of the snail are the sea slugs and there is one that frequent our grassed called the “sea hare”. This large (6-7 inch) blob colored a mottled green/gray color, moves throughout the grass seeking vegetation to feed on. When approached, or handled, by a snorkeler, they will release a purple dye as a “smoke screen” to avoid detection. Snails secrete a calcium carbonate shell from a thin piece of tissue covering their skin called a mantle. The genetics of the species determines what this shell will look like, but they are serve as a very effective against most predators. Most… some fish and others have developed ways to get past this defense. But the slugs lack this shell and have had to develop other means of defense – such as toxins and ink.
This green blob is actually a sea slug known as a sea hare. It was returned to the water.
Photo: Rick O’Connor
A separate class of mollusk are the bivalves. These do not move as well as their snail cousins but there are NO access points to the soft body when the shell is completely closed – other than drilling through. One creature who is good at opening them are starfish. Seabirds are known to drop these on roads and buildings trying to crack them open. But for the most part, it is a pretty good defense.
Bivalves possess two siphons, one drawing water in, the other expelling it, and use this not only for breathing but for collecting food – all bivalves are filter feeders. They will, at times, inhale sand particles that they cannot expel. The tend to secrete nacre (mother of pearl – shell material) over these sand grains forming pearls. Most of these are not round and are of little value to humans. But occasionally…
The pen clam is a common bivalve found in grassbeds.
Photo: Victoria College.
Oysters may be one of the more famous of the bivalves, but they are not as common in seagrass beds as other species. Most of our seagrass species require higher salinities which support both oyster predators and disease, thus we do not see as many in the grasses. Clams are different. They do quite well here, though we do not see them often because they bury within the substrate. We more often see the remaining shells after they have been consumed, or otherwise died. The southern quahog, pen shell, and razor clam are clams common to our grassbeds.
The one group sought after are the bay scallops. Scallops differ from their bivalve cousins in that they have small blue eyes at the end of each ridge on the shell that can detect predators and have the ability to swim to get away. They usually sit on top of the grasses and require them for their young (spat) to settle out. They are a very popular recreational fishery in the Big Bend area where thousands come very year to get their quota of this sweet tasting seafood product.
Bay Scallop.
Photo: FWC
There is another group of mollusk that are – at times – encountered in the seagrass beds… the cephalopods. These are mollusk that have lost their external calcium carbonate shells and use other means to defend themselves. This includes speed (they are very fast), color change (they have cells called chromatophores that allow them to do this), literally changing the texture of their skin to look and feel like the environment they are in at the moment, and expelling ink like some of the slugs. This includes the octopus and squid. Both are more active at night but have been seen during daylight hours.
The chromatophores allow the cephalopods to change colors and patterns to blend in.
Photo: California Sea Grant
As mentioned, shell collecting is very popular and finding mollusk shells in the grassbeds is something many explorers get excited about. You should understand that taking a shell with a living organism still within is not good. Some areas, including state parks, do not allow the removal of empty ones either. You should check before removing.
Since 2007 Florida Sea Grant has worked with partners, and trained volunteers, to assess the status of the diamondback terrapin in the Florida panhandle. This small emydid turtle is the only one that lives in brackish water and prefers salt marshes. Very little is known about this turtle in this part of the country, and the Panhandle Terrapin Project has the goal of changing that.
Female diamondback terrapin.
Photo: Rick O’Connor
Terrapins have strong site fidelity, meaning they do not roam much, and spend most of their day basking in the sun and feeding on shellfish – marsh snails being a particular favorite. Like many species of turtle, they breed in the spring. Gravid females leave the marsh seeking high dry sandy beaches along the shores of the estuary to lay their eggs. Unlike sea turtles, she prefers to do this on sunny days – the sunnier the better. She typically lays between 7-10 eggs, and they hatch in about two months. The hatchlings spend their early months on shore, hiding under wrack and debris feeding on small invertebrates before heading to the marsh where the cycle begins again.
The project has three objectives each year. One, to survey known (primary) nesting beaches for nesting activity. The number of nests, tracks, and depredated nests can be used to calculate a relative abundance of these animals using those beaches. Two, survey potential (secondary) nesting beaches for any presence of nesting activity. Three, tag terrapins using the old notch method, PIT tags, and a small few with satellite tags. This will help us track terrapin movement and better understand how they use the habitat.
Since the project began, we have been able to verify at least one terrapin in each of the seven panhandle counties being surveyed and have identified nesting beaches in four of those. Relative abundance is rather low when compared to other regions within their range, but those beaches remain active.
The nesting season historically begins in late April and 2023 has been busy early. Seven hatchlings that overwintered in their 2022 nests emerged and were found by volunteers, and others. Two depredated nests were located, and one nesting female was captured and tagged. The volunteers will continue to survey the rest of the spring and much of the summer. Reports of these turtles are important in our assessment. If you believe you have seen a terrapin, contact Rick O’Connor – roc1@ufl.edu – (850) 475-5230 ext.1111. and let us know where.
Female terrapin fixed with a satellite tag for tracking.
Photo: Rick O’ConnorSmall terrapin hatchling released on Santa Rosa Island.
Photo: Rick O’Connor
The Florida Fish & Wildlife Conservation Commission and UF/IFAS Extension – Florida Sea Grant have partnered to implement an innovative community-driven effort to restore scallop populations, and we need your help! “Scallop Sitter” volunteers are trained to assist in Bay, Gulf and Franklin Counties. The goal of the program is to increase scallop populations in our local bays. Scallop sitters help reintroduce scallops into suitable areas from which they have disappeared.
Volunteers manage predator exclusion cages of scallops, which are either placed in the bay or by a dock. The cages provide a safe environment for the scallops to live and reproduce, and in turn repopulate the bays. Volunteers make monthly visits from June until December to their assigned cages where they clean scallops (algal and barnacles can attach), check mortality rate and collect salinity data that helps us determine restoration goals and success in targeted areas.
1. Click on the “reserve a spot” to select the county you are participating in.*You must provide your name, contact information and date of birth to secure an FWC permit for your cage!
2. You will be sent a registration survey via email (closer to the scallops, cage & supply pickup date or you may fill out a survey onsite) , view the virtual training link: https://myfwc.com/research/saltwater/mollusc/bay-scallops/sign-up/
and you’ll receive an invite to our Panhandle Scallop Sitter Facebook Group.
DEADLINE for steps 1 & 2 are May 25th!
3. Pick up your scallops, cage & supplies!
Pickup Information (all times local)
St. George Sound Volunteers
Date: Thursday, June 1st
Time: 10:00 AM – 1:00 PM
Location: FSU Coastal & Marine Lab (across the canal – see road signage)
3618 US-98, St. Teresa, FL 32358
St. Joseph Bay Volunteers
Date: Thursday, June 8th
Time: 10:00 – 1:00 PM
Location: St. Joseph Bay State Buffer Preserve Lodge
3915 State Road 30-A, Port St. Joe, FL 32456
St. Andrew Bay Volunteers
Date: Thursday, June 16th
Time: 10:00 AM – 1:00 PM
*We know issues happen from time to time with scallop populations. It’s a bummer. If you loose a significant amount of scallops early in this year’s program, we will do our best to accommodate our volunteers with a “second wave” scallop stocking event in August. Also, looking for other ways to help our program? We plan to offer cage building workshops in the fall, stay tuned!
The open grasslands of the American west support huge herds of grazing herbivores such as bison, antelope, and deer. These large herds again support populations of hunters such as wolves, coyotes, and – historically – bears. The huge acres of wetland grasses we call marshes are productive as well, with all sorts of grazing creatures that feed on the grass like snails and insects, which in turn support populations of first order carnivores like birds, crabs, and turtles, who then feed larger predators like alligators, otters, and raccoons.
The salt marsh is full of life, if you look close enough. Photo: Rick O’Connor
One would think that the submerged seagrass meadows would work in the same way. But there are no large herds of bison like creatures that graze on the grasses. True, manatees and sea turtles do graze on these, but not in the numbers we see with bison and antelope. There are numerous species of snails and crustaceans that live in seagrass, but it is not the grass they are interested in… it is the epibiota. These epibiota are the key to vast diversity of creatures living in seagrasses. If you snorkel or seine through a submerged grassbed you will notice the majority of creatures are small. This place is a nursery for the estuarine and marine environments. These grasses provide excellent hiding places and the epibiota provide the food they need to grow.
Grassbeds are also full of life, albeit small creatures.
Photo: Virginia Sea Grant
So, what are these epibiota?
The term epibiota means “creatures that live on other creatures”. They can be further broken down into epiphytes (plants that growth on other creatures), and epizoids (animals that grow on other creatures). Spanish moss is a familiar example of an epiphyte most people know. Barnacles growing on a turtle shell, or a whale could be an epizoid you are familiar with. Many epibiota are small, even microscopic. You can see the algae growing on the shells of turtles, or the fur of the sloth. There are also numerous epizoids that are microscopic, and no one sees. It is a whole field of microbiology – the study of the natural history and diversity of this tiny world that, certainly in the case of seagrasses, makes the whole thing work.
The wide blades of turtle grass provide habitat for a variety of epibiota.
Photo: UF IFAS
With the seagrasses you will not always see the epibiota we are talking about. At times, there are mats of algae growing on the grass like Spanish moss on oak trees. We typically see these epibiotic macroalgae growing on seagrasses in the spring and summer. Most of these algal mats are red algae. Studies have shown that they support juvenile animals as hiding habitat and can increase the overall biomass of seagrass meadows. But, like with all things, too much of a good thing can have a negative effect on seagrass meadows as well. The seaweed can smother the grasses, reducing needed sunlight, and enhance the decline of seagrasses in some areas.
Gracilaria is a common epiphytic red algae growing in our seagrass beds. Photo: Rick O’Connor
Most of the epibiota feeding the growing populations of shellfish and finfish using these nurseries are microscopic plants and animals that appear to us as “scum” on the blades of the grass. As you might expect, the wider the blade (in this case turtle grass) can support a higher diversity and abundance of growing grazers than the thinner shoal grass.
A study conducted in 1964 listed 113 species of microscopic algae existing on the blades of seagrasses in Florida. They include such creatures as diatoms, cynobacteria, and bryozoans. We will focus on these.
Diatoms are quite abundant on seagrass blades and provide for microscopic grazers.
Photo: University of New Hampshire
Diatoms are single celled plant-like algae that are encased in a clear silica shell. They are one of the most abundant forms of oxygen producing plant-like creatures found in the sea. Many species drift with the phytoplankton layers of the open ocean. Others are benthic, living on the bottom upon rocks, seawalls, turtle shells, and seagrasses. It has been stated that 50% of the oxygen produced on our plant comes from the diatoms and the dinoflagellates (another microscopic plankton).
Cells of a species of cyanobacteria.
Photo: Florida Atlantic University.
Cyanobacteria are what many call blue-green algae. They produce a darker colored green with their photosynthetic pigments – thus the name blue-green algae – but were not initially identified as a bacteria – which they are now because they lack an organized nucleus. Many have heard of the recent cyanobacteria blooms in central and south Florida in freshwater systems. Some species are toxic and have caused fish kills and even made pets, who drank from water with cynaobacteria, very sick. There hundreds of different species found in marine systems. Like diatoms, some live in the water column, others are attached to an object on the bottom – like seagrasses.
This beautiful matrix was built by a group of microscopic animals known as bryozoans.
Bryozoans are microscopic colonial animals. They act and behave similar to corals, though they are much smaller. Some species appear as a “cast net” over the shell of a snail or clam, and can be seen on blades of turtle grass as well. There are many other species of these colonial creatures that call seagrass home.
We are highlighting these three groups but there are many other forms of epiphytes and epizoids growing on these grass blades. And it is these that the small grazers, like tiny crustaceans, feed upon, which in turn are what the millions of small silver juvenile finfish and crabs are feeding on. The seagrass meadow biodiversity and productivity is dependent on them and most Panhandle folks do not know they are there. Dr. Edward O. Wilson made a comment in his book Half Earth, that we have been focused on conservation of wildlife and habitat for many years now – but we fully do not understand what it is we are trying to conserve. We focus on blue crab and manatee conservation and do not realize that conservation of these micro-communities is essential for conservation, or restoration, success. The first step in conserving such communities is knowing they exist and how they support the system. You now have a little more knowledge of them, but there is SO much more to learn.
