NISAW: Working Across Boundary Lines: Because Invasive Species Do Not Recognize Your Posted Sign

NISAW: Working Across Boundary Lines: Because Invasive Species Do Not Recognize Your Posted Sign

Ken Langeland, left, and Martha Monroe, University of Florida environmental educators, examine an invasive tallow tree on Paynes Prairie near Gainesville, Thursday 10-19. They’re part of a team of researchers from UF’s Institute of Food and Agricultural Sciences and The Nature Conservancy training people how to manage environmentally sensitive lands. With more than 11-million acres of protected land, Florida needs more trained people to help protect those environmental jewels.

It is National Invasive Species Week, a time where everyone involved in natural resources, agriculture, and related fields works to raise awareness about this issue. It is an issue that costs huge sums of money to control and address, impacts economic sectors, and requires constant inspections at ports of entry to prevent new invasives from expanding the problem. Unfortunately for us, invasive species do not recognize international borders or state and local boarders for that matter. The same is true about property boundaries, which makes controlling them on the landscape difficult. They do not politely stop at the property line. So, what are we to do about the infestation when it crosses a boundary?

In Florida there is no law that requires someone to treat or remove an invasive species from the landscape. Laws do exist that prohibit the importation of species and that prohibit propagation and planting of know invasive species. Cost share programs, grants, and other efforts exist to assist private property owners and public land managers with invasive control programs and encourage the control and eradication of invasives across Florida’s landscape. Across Florida, organizations called Cooperative Invasive Species Management Areas (CISMA’s) exist to help coordinate efforts and provide educational outreach. The CISMA that covers Walton and the surrounding counties is the Six Rivers CISMA, and this outstanding organization even crosses state boundaries to include adjoining Alabama counties. This cross-state collaboration is an outstanding example of working across boundaries to accomplish a common goal. You can learn about the Six River CISMA and it’s efforts to  invasive species through their website (LOCAL PRIVATE LANDS ASSISTANCE – Six Rivers Cooperative Invasive Species Management Area ( ). Our outstanding University of Florida IFAS extension service provides research and education across the state to help inform control efforts and coordinate through a network of experts from research professionals to local county extension agents. All of these efforts are making great progress in the control and management of invasive species.

One issue still stands out as a major challenge in taking on invasives, and that is that the ability to do control stops at a property line. This is especially true for some of our worst invasives like cogongrass, Japanese climbing fern, Chinese privet, and tallow tree; just to name a few. While animals move and you can trap or remove them as they come across your property; plants stay in place and often spread in an area. If that area happens to be right along a boundary, something like a fence row, the infestation often spreads across the property line. Add to that the fact invasive species, because of the disturbance and vegetation changes, often thrive and colonize in areas like fence rows and you have a major issue. That plant doesn’t see that posted sign and the property owner must stop any treatment effort at that point. Legally a landowner cannot cross a property line, and is liable for doing so especially when mowing, burning, or spraying herbicides. Putting herbicide on a neighboring property, even if it was accidental drift, is a major no go and can land the two parties in court. At best in this situation a property owner has a good relationship with neighbors and can work something out to control the infestation. If not, the treatment must stop where the ownership stops.

Why is it a problem that a treatment stops at the property boundary? Well, cogongrass is a great example. Cogongrass is a major problem in Walton County, and across the Panhandle in general. The western panhandle and southern Alabama are considered the epicenter of this invasive, and in Walton County it is spreading like wildfire. That’s somewhat literal too as this invasive grass massively increases fire intensity and spreads. My fellow extension agent from Gulf County,  Ray Bodrey, just wrote a great article about this grass and the issues it is causing. I won’t duplicate his effort and expound on how to identify it. You can see his article here NISAW: A Spreading Menace in Gulf County, known as Cogongrass | Panhandle Outdoors ( Needless to say, if two county agents list it as one of the top issues, then we need to focus on it.

This grass spreads rapidly and easily, especially along roadsides, right of ways, and fencerows. You might wonder why that is? Well it happens to love to hitch a ride on equipment or move in contaminated fill dirt. Add to that it is tough to kill and takes multiple years of herbicide treatment to do the trick; and you have what has been identified as the Gulf Coast’s worst invasive. In fact, it is usually listed as one of the worst invasive species worldwide. Tack all that together and throw the fact that you cannot always work across a boundary and you’ve got quite the intractable issue. And that is just our top offender, we still haven’t touched tallow tree and the other of Six River CISMA’s “Dirty Dozen”.

What can be done then if invasives are such a herculean task that requires cross boundary management? We have several options, many of which I mentioned earlier in the article. Lots of work is being done right now by everyone from private landowners to local governments and even at the federal level. Here in Walton County the local public works has an active program to report and control cogongrass in the roadway and other county right of ways. They use in house and contract teams to report, track, and treat cogongrass infestations. This is a great effort and shows a great proactivity on the part of the county government. The program will go a long way in the congongrass control effort, but it still must stop at the right of way. If the infestation goes onto private property, it is then on the private property owner to have a control plan. Without some good communication the property owner may not even realize the problem is there.

Cogongrass is a good example of why it pays for a private landowner to treat an infestation too. This grass has no forage value and chokes out any other crops, lowering agricultural yields and values. It ruins yards, turf grass, and golf courses along with dulling and damaging mowing equipment. It contaminates fill dirt and borrow pits and then spreads to areas as development and construction occurs. If you are in the fill dirt business, clients that know usually reject soil that is contaminated or could be contaminated with cogongrass rhizomes. Forest landowners suffer major impacts from this invasive grass as it makes reforestation next to impossible, increases wildfire risk, makes using prescribed fire difficult at best, reduces timber yields, and ruins the habitat value for wildlife. An unchecked cogongrass infestation can ruin land values and it will do that as it spreads across onto other property.

 This loss of land value is not just conjecture either.  An article published in the Journal of Agricultural and Applied Economics from research performed by scientists from the University of Florida and the University of New York found that cogongrass infestations in slash pine forests reduce the return on investment and the land value. The study (Alavalapati et al 2007) looked at the impact of cogongrass infestation on rates of return and land values in several situations: no threat of infestation, infestation uncertain with no management, infestation uncertain with treatment by one landowner, and infestation uncertain with treatment by all landowners. The study found that cogongrass negatively impacts rental rates and the land value. To assess the land value, they used a forestry measurement called the Land Expectancy Value, which is a formula that uses the expected productivity of the land, input costs, and expected timber value to determine how valuable timberland is. The study found that the land value can be decreased by up to 50% on timberland.  The study also found that the annual net returns per acre are decreased by between $17.00 and $25.00 depending on the infestation and management scenarios. Those are big economic and land value impacts, and that is just for forested lands. The big finding was that the scenario that resulted in the biggest loss of land value and returns was when only one landowner was treating. Alavalapati et al 2007 found that when control measures are undertaken by all landowners in an infestation zone the impacts are lowest and the most value is preserved. They suggest that the study results show the best outcomes will be when collaborative efforts are used. While the study only looked at cogongrass, the methodology and results are applicable to other invasive species. Working across that property line has real economic benefits as well as all the ecological and landscape benefits that come from invasive species control.

Donn Shilling and Eldridge Wynn look over a research field of cogongrass, which has become a problem for cattle ranchers.

Practical experience shows that this collaborative approach works as well. Since 2004 the Georgia Forestry Commission and the State of Georgia have implemented a cogongrass task force. Georgia recognized the severity of the issue early on, to some degree from seeing what was occurring in Florida and Alabama. They also recognized the state could not completely prevent cogongrass from entering the state but could be proactive at control and eradication. They launched a collaborative effort lead by the Georgia Forestry Commission, where landowners and others would report congongrass and the infestation would be identified and treated at no cost to the landowner. The program was structured where they could work with other landowners at an infestation site as well. The program also implemented a tracking and follow up program, which tracked the infestation until it was eradicated or became inactive. In 2007, 72 Georgia counties had detections, but as of 2021, 34 of those 72 have no active cogongrass and 85% of all known cogongrass spots in Georgia are inactive (2021-Dirty-Dozen-List.pdf ( That is a huge success and something that can be replicated in other states. This program took federal and state funding, state and local government involvement, coordinated tracking, and reporting and detection from landowners. It could not have happened without this collaborative effort that reached across boundaries.

Could we see something like this in Walton County or across the Panhandle? Absolutely, we could definitely build a collaborative effort on one or more invasives. Cogongrass is a great place to start, and even though it is so difficult to eradicate we have evidence that a program can be successful. What it takes is reaching across boundaries and the “Think Global, Act Local” approach, or as the Florida Invasive Species Partnership puts it “Think Locally, Act Neighborly”. Florida does not have a statewide coordinated cogongrass control effort like Georgia, but the nature of the issue in Florida is very different. Given the size and scope, a Florida eradication program would likely look much different. But why wait for a statewide program like Georgia? It would be much easier to replicate a cooperative program on invasive species at the county level. It will take working across boundaries and communicating across communities and ownerships; but we know it works. The bottom line is that inaction will result in a growing and extending problem, spreading across more and more ownerships and areas. Invasives are not just an ecological or environmental problem either, they impact land values and our economy too. The information we have shows that when control efforts are sporadic and individual; economic impacts are actually higher because landowners controlling the invasive incur costs while infestations persist in an area. To keep our land base productive and valuable we have to work together and take community efforts. This is everything from identifying and tracking infestations to control and monitoring. If it can work with cogongrass, it will work with the other major invasives as well. Most of our greatest achievements as Americans, things like making it through the Great Depression, building the Transcontinental Railroad, or winning World War II, have been through collaborative efforts. Invasive species control is going to be the same thing, and research and results on cogongrass show reaching across boundaries works. Invasives move across boundary lines; so we need to work across them to be successful. A collaborative cogongrass effort would be a great start, and then we can expand.

References and Resources

Alavalapati, J. R. R., Jose, S., Stainback, G. A., Matta, J. R., & Carter, D. R. (2007). Economics of Cogongrass Control in Slash Pine Forests. Journal of Agricultural and Applied Economics39(s1), 61–68.

Georgia Forestry Commission: Invasive Plant Control Program

Georgia Forestry Commission 2021 Dirty Dozen List 2021-Dirty-Dozen-List.pdf (

Six Rivers CISMA Webpage Home – Six Rivers Cooperative Invasive Species Management Area ( Florida Invasive Species Partnership Home – Florida Invasive Species Partnership

NISAW: A Spreading Menace in Gulf County, known as Cogongrass

NISAW: A Spreading Menace in Gulf County, known as Cogongrass

Ray Bodrey, Gulf County Extension Director

Cogongrass continues to be a thorn in the side of many landowners and municipal public works departments, as it spreads in areas across the Panhandle, with Gulf County being no exception. Thankfully, there are ways to combat cogongrass, but it seems to be an uphill battle. Identifying and being persistent with treatment are paramount in control.

Figure 1: Cogongrass infestation and uneven mid-rib in leaf blade.

Credit: Ray Bodrey, UF/IFAS Extension Gulf County.

Cogongrass (Imperata cylindrica) is found all over the world. In the U.S, it is primarily found in the southeast. Cogongrass was purposely introduced as a soil stabilizer for pasture lands in Florida during the 1930’s and 1940’s. It wasn’t long before ranchers and agricultural scientists realized that cogongrass was an invasive species. Once established, cogongrass has the ability to overrun pastures and natural areas to the point that it will be the only plant species occupant. It’s a perennial grass with a vast, ever expanding root system. This grass can grow in any soil type and low soil fertility nor drought, are concerns either. Therefore, it thrives no matter how poor the soil environment. Even with multiple days of periods of well below freezing temperatures and a prior application of herbicide, figures 1 & 2 display the resiliency of cogongrass. The major concern is the ability to eliminate native plant habitat.

Cogongrass can be confused with other grasses, like switchgrass. This is especially possible early in the year before the bloom. To identify cogongrass, first investigate the growing pattern. It usually infiltrates an area in patches. As shown in figure 1, the grass blades are flat and have a defining white mid-rib. Blades are finely serrated, yellow to green in color and are uneven in width on each side of the mid-rib. The seed head is fluffy, white and feather shaped. The seed head can alarmingly yield 3,000 seeds per head.

Figure 2: Cogongrass spreading.

Credit: Ray Bodrey, UF/IFAS Extension Gulf County.

The management strategy most successful with eradicating cogongrass consists of multiple types of herbicides sprayed over multiple year applications, with additional spot treatments. Prescribe burning can also be used in concert as an integrated approach.

For control measures, see the tables in the document referenced below. Also, contact your local county extension agent for further details.

Information for this article is from the UF/IFAS EDIS publication: “Cogongrass (Imperata cylindrica) Biology, Ecology, and

Management in Florida Grazing Lands” by B. A. Sellers, J. A. Ferrell, G. E. MacDonald, K. A. Langeland, and S. L. Flory:

UF/IFAS Extension, An Equal Opportunity Institution.

NISAW: Wild Hogs, an invasive species to Escambia County

NISAW: Wild Hogs, an invasive species to Escambia County

Wild hogs, also known as feral pigs, are a common group known throughout Florida, including Escambia County. Brought in by early settlers, these beasts have become an invasive species that cause serious damage to whatever environment they enter. In Escambia County they are found in various habitats which include forests, swamps, and agricultural areas.

These creatures are omnivorous and feed on essentially anything they can find. They uproot and feed on plants, roots, and insects, as well as prey on nests, eggs, and the young of ground nesting birds, small mammals, and reptiles. This, in turn, damages the land and continues to create competition for native wildlife.

Wild hog populations can rise quickly with sows able to produce multiple litters of piglets in a year.

To seek control of the wild hog population, hunting is allowed in Escambia County with a valid license. However, this alone is not enough to manage the ever-growing population. Therefore, other control measures such as trapping may be necessary.

Wild hogs are known to be carriers of many diseases which can be transmitted to livestock, other animals, and even humans. It is important that anyone who attempts to hunt or trap wild hogs take every precaution.

As they are a significant issue that can cause economic and ecological damage, it is important to take action to manage their populations, and to minimize the impact they make on the local environment and agriculture.

In this image, feral hogs have rooted up around this bottom and have caused a significant amount of damage.
Credit: Madelyn Grant

Here are some helpful links to learn more about Feral Pigs:

NISAW: Giant salvinia

NISAW: Giant salvinia

Despite its name, giant salvinia (Salvinia molesta) is actually pretty small. The floating plant starts out with a cluster of leaves no bigger than a dime. They don’t stay that way, though, and perhaps their outsized influence and spread gives the “giant” a little more credence.

Giant salvinia is an invasive aquatic plant that was introduced to the United States as an ornamental plant (for aquariums and backyard ponds) from South America. Once it managed to escape to the wild, however, salvinia really took off. More than 20 states report salvinia popping up in their waters, although Texas and Louisiana seem to have the biggest battles with it. The plant has choked up entire freshwater lakes and sections of rivers, requiring a major eradication effort just to regain access to the water. Even small craft like kayaks and canoes cannot make it through a water body clogged with this plant. It is often spread by small pieces lodging in boat motors and trailers, so if you boat frequently in an area of known salvinia, be sure to remove any fragments of the plant once you are back on land. Preventing the spread from one water body to another is crucial.

Our native birds, fish, and aquatic mammals don’t eat giant salvinia—it appears not to have much nutritional value—and therefore its growth goes unchecked. The thick mats of plant growth block sunlight into the water column, preventing other aquatic plants from growing. Die-offs of large numbers of salvinia can eat up oxygen levels in the water, causing fish kills.

Giant salvinia overgrowth in a backwater section of Bayou Chico in Escambia County. Photo credit: Escambia County Natural Resource Management

There are several approaches to managing the plant. Mechanical or hand removal can take out significant amounts of salvinia, but is ineffective in the long run. Any small piece of chopped up plant left behind in the process will regrow into new spreading plants, so leaving any fragments in the water ends up increasing the population. More effective methods include applying herbicides or using a biocontrol insect called the salvinia weevil. This South American beetle (Cyrtobagous salviniae) is very small (only 2 mm as an adult) but feeds exclusively on salvinia plants, stunting their growth and causing them to sink underwater. A well-established salvinia weevil population can effectively manage large infestations of the plant, dropping coverage by 90%.

One natural check to unfettered growth in our area is that salvinia tends to thrive only in freshwater or very low salinity water bodies. We have identified populations of salvinia in the upper reaches of local bayous in Escambia County, but as salinity levels increase closer to the bay, the plant seems unable to establish itself.

Identification of giant salvinia is rather fascinating, as you need a hand lens to definitively distinguish it from a very similar nonnative species called water spangles or water fern (Salvinia minima). Both species have small clear-white, upright hairs covering the leaves. When examined closely, the observer will note that in giant salvinia that double pairs of hairs form a structure very similar to an egg beater, whereas in water spangles the leaf hairs do not connect.

Giant salvinia can be distinguished from its cousin, common salvinia (Salvinia minima) by the shape of its trichomes, or leaf-hairs. Giant salvinia’s leaf hairs (right) are closed at the tip, forming an “egg-beater” shape, whereas common salvinia’s leaf hairs (left) are branched at the tip. Giant salvinia is a larger plant that forms thicker, denser mats. Common salvinia can cover large areas but typically forms thinner mats and does not pose as much risk to boating traffic. Photos and caption courtesy LSU AgCenter

If you think you see giant salvinia in a local water body, we would love to know. It is an aggressive invasive plant that is relatively new to the area, and we have a chance to keep this from spreading with your help. What can you do?

  • Contact the Escambia County Division of Water Quality and Land Management – (850) 595-3496
  • Contact the Escambia County Extension Office – (850) 475-5230 ext. 1111
  • Report in the EDDMapS national database – – select “report sightings”
  • If you find just a small amount, remove it and allow to dry out on your property. Once dried you can double bag and dispose of it.
NISAW 2023; Invasive Animals in Escambia County

NISAW 2023; Invasive Animals in Escambia County

There are more invasive plants issues in Escambia County than animal ones; but we do have animal invasives.  Some have been with us for some time, like the feral hogs which will be posted in a different article, some are more recent.  In this article we are going to focus on two species that could become real problems for us without some management plan – the lionfish and the Cuban treefrog. 

The Invasive Lionfish

The red lionfish (Pterois volitans) has been in the local news for some time – but as a Gulf of Mexico problem.  The fish is from the Indo-Pacific region of the world and was brough here for the pet trade.  The first records we have of it in the wild were in southeast Florida in the 1980s.  We are not 100% sure how they reached the Atlantic Ocean, but they did – and they did well. 

Lionfish display a courtship dance where, near sunset, the males and females rise off the reef in a rotating swimming pattern and then fertilize their eggs.  On average, each female will fertilize 30,000 eggs every four days!  These fertilized eggs are encased in a gelatinous sac that drifts with the currents and is a method of spreading the species across the region.  Originating in southeast Florida, the Gulf Stream dispersed them north along the coasts of Georgia and the Carolina’s.  From here the invasion moved east to Bermuda where the Atlantic currents cycled them back south to the Caribbean, here they invaded every reef system in the region.  From the Caribbean they found there way to the Florida Keys and eventually into the Gulf of Mexico.  The first record in Escambia County was in 2010.  It has been described as one of the most prolific, and successful, invasions of a non-native species ever. 

Studies show that the invasion in the Pensacola area was particularly bad.  One study showed that the densities in our area were some of the highest in the south Atlantic region.  Another study showed they had preference for artificial over natural reefs.  In response, the Escambia County Division of Marine Resources, partnering with Florida Sea Grant, developed a series of local workshops to educate the public about the issue. 

From these meetings nonprofits formed that began to have “rodeos” and “roundups” providing prizes to divers who could remove the most, the largest, and even the smallest lionfish.  Eventually the Florida Fish and Wildlife Conservation Commission (FWC) joined in and created the Lionfish Removal and Awareness Day (LRAD).  This event, which began in Pensacola, attracted thousands of curious people, chefs cooking samples, and divers from across the region.  These efforts, along with an increase in commercial harvest (the fish is edible) have made a significant impact on populations in waters less than 200 feet (where divers can safely work) – but lionfish can live as deep as 1000 feet.

In 2019 a gentlemen fishing on the pier at Ft. Pickens caught one on hook and line.  Charter captains have been catching them on hook and line for a few years but it was not common and usually in low numbers.  Over the nine years since the first record, there had also been three records within Big Lagoon, so – finding one inside of the pass was not new, but concerning.  Partnering with the Ocean Strike Team, Sea Grant conducted a series of survey dives to assess the status of lionfish near the pier and jetties of Ft. Pickens.  They found them – though in small numbers, lionfish were present. 

The question now is how far within the bay has this invasion spread.  The concern is two things. 

  • Lionfish are gregarious feeders – eating just about anything they can get into their mouths.  Offshore they are known to eat no fewer than 70 species of small reef fish, including the commercially important vermilion snapper, and several invertebrates, including shovel nosed lobsters.  If they invade the bay, we are now looking at juvenile shrimp, blue crabs, flounder, redfish, and more.  The impact could be very big. 
  • They are venomous.  Not by bite, but by spines.  Though it has not killed anyone, the “sting” of a lionfish is extremely painful and placed some in the hospital.  With numerous locals and visitors swimming in our estuarine waters, encounters with this fish will occur, and problems with envenomation will follow.   

The response needed from the county is to develop a management plan for this fish in our bay.  Studies show that the most effective, and least costly, methods occur at the early stages of the invasion – Early Detection Rapid Response.  There are several agencies, including Florida Sea Grant, ready to assist with this. 

Cuban Treefrog Photo: UF IFAS

As the name implies, the Cuban treefrog (Osteopilus septentrionalis) is from Cuba – though it is native the Bahamas and the Cayman Islands as well.  Records show they arrived in the Florida Keys in the 1920s – most likely “hitchhiking” on boats crossing the Florida straits. 

This is a large treefrog, can reach six inches – compared to the two inches of our native frogs, and quickly moved in consuming local wildlife.  As with many invasive species, their numbers increased quickly, and they became common across the landscape.  In most locations where Cuban treefrogs were present, NO native frogs could be found.  Studies show that in pools where Cuban treefrog tadpoles exist, no native tadpoles survive.  Native frog populations began to decline.  This is a large treefrog, not only do they consume native frogs, but they also consume small lizards, snakes, and all sorts of insects. 

But the problem goes beyond native ecology.  These treefrogs love to be around humans.  Residents complain of the numbers of these large frogs on their doors and windows in the evening.  They defecate making a large mess and the calls of the males sounds like a squeaky screen door keeping folks up at night – especially when they are abundant and there are no other frogs in the neighborhood.  They are known to enter vent pipes in the plumbing, sometimes clogging these pipes, often appearing in your commode when you lift the lid to use the restroom.  People do not like them.  They are also known to hideout in electric panels and often short circuit home electrical and HVAC systems.  Some of these problems become costly to the property owners. 

The Cuban treefrogs have dispersed out of south Florida.  They are now established as far north as Gainesville, Jacksonville, and Cedar Key.  But records in the Florida panhandle, including Escambia County, are increasing. 

Our part of the state was once immune to invasions of tropical species such as this frog.  Our winters were cold enough to eradicate the few that made it here.  We think the most frequent method of invasion is by hitchhiking – just as they originally did.  Many of the landscaping plants we purchase for our homes and neighborhoods are grown at large nurseries in south Florida.  These plants are loaded onto trucks and brought here – bringing Cuban treefrogs, Brown anoles, and many other small frogs and lizards that can be a problem for us.  It appears that our winters are becoming milder, and these invaders are now surviving.  Dr. Steve Johnson (University of Florida) has verified a breeding colony of Cuban treefrogs in Bay County.  Records and calls from Escambia and Santa Rosa counties are increasing.  We do not know whether these populations are breeding – but the concern is there. 

Florida Sea Grant plans to develop a citizen science monitoring project in the spring of 2023 to assess the status of these frogs in our county.  As with the lionfish, early detection – rapid response is the key to managing them. 

If you are interested in participating in either the bay lionfish surveys, or the Cuban treefrogs surveys in Escambia County, contact Rick O’Connor at the Escambia County Extension Office.