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 – https://www.eddmaps.org – 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.
Kayaking through a crystal blue spring, hiking among longleaf pines and discovering gopher tortoise burrows, gliding past alligators by boat in Mobile Bay, private tours of the EPA lab on Pensacola Beach, and meeting hundreds of fascinating, like-minded people—these are just a handful of fond memories from my experiences teaching the Florida Master Naturalist Program. Having recently celebrated its 20th anniversary, the Florida Master Naturalist Program (FMNP) has inspired the creation of dozens of similar courses in other states and proven itself to be one of the most popular outreach programs to come out of UF IFAS Extension.
Kayaking Santa Rosa Sound in Navarre is one of the highlights of our Coastal Systems FMNP class. Photo credit: Carrie Stevenson, UF IFAS Extension
The mission of the FMNP is simple—to promote awareness, understanding, and respect of Florida’s natural world among Florida’s citizens and visitors. I have always felt strongly that if you want people to care about something, they need to understand it. And to really understand something, you need to experience it. I know my own passion for science and ecology was ignited early on by teachers who took us outside and helped us encounter the many wondrous surprises in the natural world. With FMNP, we seek to do just that.
Over a span of 40 hours in 7-8 weeks, we spend about half our time with classroom presentations and the other half in the field, seeing the plants, animals, and ecosystems we discuss in class. In addition to classes and field trips, students produce a final project and present it to the class. These can range from labeled collections and slide presentations to building bird houses and new trails. The program is composed of three 40-hour core courses; Coastal, Upland, and Freshwater Systems. Seven “short courses” with 24 hours of class/field time include the Land Steward series (Conservation Science, Habitat Evaluation, Wildlife Monitoring, and Environmental Interpretation) and the Restoration courses (Coastal Restoration, Marine Habitat Restoration, and Invasive Plants). Locally, we try to rotate the core modules every couple of years and incorporate the short courses periodically. The registration fee per core module is $250 – $300 and includes a detailed course manual and, upon completion, FMNP patch, certificate, and pin denoting area of expertise. There are a handful of scholarships available for those interested in applying to offset costs.
This trail and boardwalk in Perdido Key were part of a multi-stage FMNP final project highlighting multiple ecosystem types. Photo credit: Jerry Patee, Master Naturalist
The classes do not count towards university credit, but are an excellent certification and professional development opportunity that look great on a resume. While we’ve had ecotour operators, park rangers, environmental consultants, teachers, and archaeologists (and many seeking employment in the environmental field), most of our FMNP students are not professionals in the field. They come from every background imaginable, but share an interest in the outdoors. Because we meet weekly, class members often bond and create long-lasting friendships during the courses.
Extension Agents in northwest Florida are offering two Master Naturalist courses, starting in the next few weeks. In Escambia and Santa Rosa County, we will have an in-person daytime Coastal Systems class starting March 28 and running through May 16. Walton County is teaming up with Miami-Dade to offer an evening hybrid (online class sessions, in-person field trips) Freshwater Systems course from February 18 to April 13. FMNP classes are restricted to adults 18 and over, but a new “Florida Youth Naturalist” curriculum has been designed through our 4-H program for young people. For more information on that, check out their website.
Master Naturalist students conduct field work in small groups. Photo credit: Carrie Stevenson, UF IFAS Extension
As the name implies, they are haunting—long stretches of standing, dead trees with exposed roots. These “ghost forests” are an unsettling scene in unsettling times for the environment. While coastal erosion is a fact of life—incoming waves, hurricanes, longshore drift of beach sand—the rate of its occurrence is startling lately.
Exposed roots of a ghost forest forming along the Escambia Bay. Photo credit: Deanie Sexton
Global rises in sea level due to increased atmospheric carbon levels mean more saltwater is moving into flat, coastal habitats that once served as a buffer from the open water. Salt is an exceedingly difficult compound for plants to handle, and only a few species have evolved mechanisms for tolerating it. Low-growing salt marshes and thick mangrove stands have always served as “first line of defense” buffers to take in wave action and absorb saltwater. If shorelines have too much wave action for marshes to form, wide stretches of sandy beach and dunes serve the same function, protecting the inland species of shrubs and trees. Many coastal areas are flat and stay at or just above sea level for thousands of yards, or even miles. This means that even a small increase in sea level can send saltwater deep into previously freshwater systems, drowning the marsh and flooding stands of oak and pine. The salt and sulfate in seawater will kill a tree quickly, although it may remain standing, dead, for months or years. Hurricanes and tropical storms exacerbate that damage, scouring out chunks of shoreline and knocking down already-unstable trees.
A slow increase in sea level could be tolerated and adapted to as salt marshes move inland and replace non-salt tolerant species. But this process of ecological succession can be interrupted if erosion and increased water levels occur too quickly. And if there is hard infrastructure inland of the marshes (like roads or buildings), the system experiences “coastal squeeze,” winnowing the marsh to a thin, eventually nonexistent ribbon, with no natural protection for that expensive infrastructure.
This diagram outlines the changes in coastal vegetation and shorelines as sea level rises. With “ghost forests,” the sea level moves into that coastal forest section. Figure credit: W. Gray, IAN Image Library
Ghost forests are popping up everywhere. Last year, Popular Mechanics magazine reported on a recently published study that used satellite imagery to document how 11% of a previously healthy forest was converted to standing dead trees along the coast of North Carolina. The trees died within a span of just 35 years (1984-2019). During that time frame, this stretch of coastline also experienced an extended drought and Category 3 Hurricane Irene. These impacts sped up the habitat loss, with over 19,000 hectares converted from forest to marsh and 1100 hectares of marsh vegetation gone, becoming open water.
A ghost forest forming along the shoreline of Blackwater Bay in Santa Rosa County. Photo credit: Carrie Stevenson, UF IFAS Extension
Due to increased coastal flooding and saltwater standing in forested areas, U.S. Fish and Wildlife Service employees are concerned that the historic Harriett Tubman Byway in Maryland—part of the famed underground railroad of the Civil War era—will soon be gone. Over 5,000 acres of tidal marsh have converted to open water in the area and large stands of trees have died. Even locally, trees along Escambia and Blackwater Bay are dying due to salt damage and heavy erosion. Hurricane Sally delivered a knockout punch to many remaining trees along the scenic bluffs of the bay.
Sea level has risen over 10” in the past 100 years in the Pensacola Bay area, and even mid-range Army Corps of Engineers estimates expect 0.6 to 1.4 feet of rise in the area by 2045. There are some actions we can take to mitigate future damage. Building a “living shoreline” of vegetation along a piece of waterfront property instead of using a seawall can help, especially if the vegetation growth outpaces sea level rise. You can also visit the City of Pensacola’s Climate Task Force report to learn more about climate action recommended (and being taken) locally, such as increasing the use of renewable energy and dedicating staff to sustainability measures.
Coastal plain honeycombhead blooms through the summer on local beaches. Photo credit, Bob Pitts, National Park Service
Over my years of leading people on interpretive trail hikes, I have learned it is particularly important to know the names of whatever happens to be in bloom. These flowers are eye-catching, and inevitably someone will ask what they are. In fact, one of my favorite wildflower identification books is categorized not by taxonomy, but by bloom color—with a rainbow of tabs down the edge of the book for easy identification.
Wildflower identification can be tough, but color-coded guidebooks are really helpful! Photo credit: Carrie Stevenson, UF IFAS Extension
In our coastal dunes right now, several plants are showing off vibrant yellow blooms. Seaside goldenrod, coreopsis, and other asters are common. Rarer, and the subject of today’s post, is the Coastal Plain Honeycombhead (Balduina angustifolia). It has bright yellow flowers, but often gets more notice due to its unusual appearance when not in bloom. The basal leaves are bright green and similar in shape and arrangement to a pine cone or bottlebrush (albeit a tiny one), sticking straight up in the sand. The plants are typically found on the more protected back side of primary dunes or further into secondary dunes, a little more inland from the Gulf.
When not in bloom, the plant resembles a green pinecone planted in the sand. Photo credit: Carrie Stevenson, UF IFAS Extension
The plant plays a special role in beach ecology, as a host plant for Gulf fritillary butterflies and the Gulf Coast solitary bee (Hesperapis oraria). The bee is a ground-dwelling pollinator insect that forages only in the barrier islands of Mississippi, Alabama, and Florida. The species is currently the subject of a University of Florida study (they’re out at Ft. Pickens right now), as the endemic bee’s sole source of nectar and pollen is the honeycombhead flower. As of publication date, no bee nests have been discovered. Researchers are interested in learning more about the insect’s life cycle and nesting behaviors to better understand and protect its use of local habitats. Based on closely related species, it is believed the Gulf Coast solitary bee builds a multi-chambered nest under the soft sands of the dunes.
Adult female Hesperapis oraria foraging on coastal plain honeycombhead (Balduina angustifolia). Photograph by John Bente, Florida Department of Environmental Protection, Florida Park Service.
While the honeycombhead plant is found in peninsular Florida and coastal Georgia, the bee has been identified only in a 100 km² area between Horn Island, MS, and St. Andrews Bay, FL. Luckily for the bee, large swaths of this land are preserved as part of Gulf Islands National Seashore and several state parks. Nonetheless, these coastal dune habitats are threatened by hurricanes, sea level rise, and development (outside the park boundaries). Due to its rarity and limited habitat, a petition has been submitted to the Fish and Wildlife Service for protection under the Endangered Species Act. 0
Morrison Springs in Walton County is a natural spring ideal for paddling, snorkeling, and diving. Photo credit: Carrie Stevenson, UF IFAS Extensio
There is just SO much water in Florida. Besides the tremendous amount of rain and 1,350 miles of coastline and beachfront, there are endless bays, bayous, creeks, rivers, and streams. In this state, it is extraordinarily difficult to live more than a few miles from a body of water. Among the the coolest (literally) types of water bodies in Florida, though, are our springs. Like brilliant gemstones, the state’s 700+ springs dot the Florida landscape like a strand of sapphires.
While we have springs bubbling up all over northwest Florida in areas where the underground water table meets the surface, larger springs are more common as you move east and south. Some parts of north Florida and most of the peninsula are built on a limestone platform, known by the geological term “karst.” Limestone is composed of calcium carbonate, which has a porous and easily degradable chemical structure. When this barrier is breached, it allows the cold groundwater an opening directly to the surface water—hence a spring. (Fun fact—there are surface water streams that actually disappear into a spring—these are called swallets, operating as the reverse version of a spring!)
The striking blue-green water in Three Sisters Spring is only accessible by kayak or swimming. Photo credit: Carrie Stevenson, UF IFAS Extension
A few of the largest springs in northwest Florida are Vortex, Ponce de Leon, and Morrison Springs, found in Holmes and Walton County. Vortex is a privately operated water park and scuba diving/training facility. It is where the red and white “diver down” flag was invented and has a complex underwater cavern system. Ponce de Leon and Morrison Springs are state and county-run parks with a more natural feel, surrounded by woods and basic infrastructure for access. Morrison will especially wow visitors with its tremendous turquoise coloring.
Crystal clear water in Morrison Springs. Photo credit: Carrie Stevenson, UF IFAS Extension
Before a meeting in Crystal River last week, I paddled and snorkeled through the famous Three Sisters Spring. As part of Crystal River National Wildlife Refuge, it is a popular but highly protected area. Three Sisters is well-known as a manatee gathering place, especially in winter, but during my visit was mostly unoccupied. The color was striking, though. Why do so many of these springs have such brilliant blue and turquoise coloring? The phenomenon is essentially the same as the blue-green Gulf waters in the Panhandle. The reflection of the sky on a sunny day with the backdrop of that pure white sand causes the water to reflect a color that inspired the nickname “The Emerald Coast.” In springs, the white calcium carbonate in limestone breaks down into tiny crystals, mixing with the water and reflecting the vivid shades of blue.
Alexander Springs Creek in Ocala National Forest is overrun with algae. Photo credit: Matt Cohen, UF IFAS
Besides their beauty, clarity, recreational, and wildlife value, springs pump 8 billion gallons of fresh water a day of into Florida ecosystems. Seagrass meadows in many of these springs are lush. Because they are literal windows into the underground aquifer, they are extremely vulnerable to pollution. While many springs have been protected for decades, others were seen as places to dump trash and make it “disappear.” Many have been affected by urban stormwater and agricultural pollution, losing their clarity, reducing dissolved oxygen levels, and prompting massive cleanup and buffer protection zones.
On one of these hot summer days in Florida, take the time to visit our incredible springs. While it may not be the literal “Fountain of Youth,” swimming in a spring is a unique and invigorating experience, and a beautiful way to get off the beaten path. A comprehensive guide to Florida springs, research, and statewide protection initiatives can be found at the Florida Department of Environmental Protection’s springs website.
0
