By: Elliott White Jr. Doctoral Student in UF’s Environmental Engineering Sciences Department
The Historical Suwannee River
The Suwannee River is both a cultural and ecological landmark for the state of Florida. Over the course of its long history there has been very little alteration to the physical form of the river. These alterations can come by way of damming, dredging, or bank widening. The Suwannee is one of the few large rivers in Florida that one can still consider “natural,” meaning that the only changes to the river are from naturally occurring processes. Due to these factors, the river has been deemed an Outstanding Florida Water by the Florida Department of Environmental Protection. This designation puts special regulations on the river that limit activities that could impact the river’s water quality. The same cannot be said for the forest surrounding the river. Despite almost no alterations to the Suwannee River itself, the floodplain forest on the riverbanks have seen substantial use and change by humans over the course of the river’s history. The portion of forest closest to the Gulf of Mexico may be facing a new threat.
The river’s headwaters are in the historic Okefenokee Swamp located in southeastern Georgia. From there it flows down on a roughly southwestern route into Florida. The Suwannee grows in size as it merges with the Alapaha and Withlacoochee Rivers near Falmouth, FL. Further south the Santa Fe River merges with the Suwannee River south of Branford, FL. In addition to these three rivers there are also 27 springs sporadically appearing on the banks of the Suwannee River including Fanning and Manatee Springs. The river makes its way to the mouth near Suwannee, FL. The river empties into the Gulf of Mexico after having traveled 246 miles and through 8 Florida counties. During most of the Suwannee River’s journey the banks are lined with trees. The floodplain forest has been used extensively over the course of millennia. This is especially true for the lower portion of the river which has been used by humans for several thousand years by both indigenous and colonizing peoples.
Native American tribes native lived up and down the Suwannee River. The river served many useful functions which include serving as a source of food and travel for trading. In addition, the forest was used for timber for building wooden dugout canoes. It wasn’t until European Americans settled on the river that drastic changes started to occur to the floodplain forest. Much of the floodplain forest along the Suwannee River from Oldtown, FL, and further south were logged extensively from the mid-1800s to the 1940s. This process fundamentally changed the floodplain landscape. However, in the decades since this period, the floodplain has been able to recuperate. The floodplain forest that we see when visiting Fowler’s Bluff is not the forest of old, but a good representation of what once was. Many of the forests are protected by being included in conservation land like the Lower Suwannee National Wildlife Refuge. Some of the floodplain forests closer to the mouth of the river are under assault again. Unfortunately, no state or even federal law can provide a quick fix to keep the threat at sea.
Impending Sea Level Rise
Sea level rise is threatening the longevity of the trees further south on the river. Sea level rise is a double edged sword that also includes saltwater intrusion. The floodplain forest along the lower Suwannee River are composed of freshwater species such as baldcypress (Taxodium distichum), tupelo (Nyssa spp.), and ash (Fraxinus spp.). These species can tolerate small amounts of saltwater, however, this will impact their health over a long period of time. As saltwater gets more concentrated and lingers longer in these systems, there will be noticeable changes that start to take place. This will ultimately end in these forests being converted into salt marsh. The early stage of this transition is the lack of regeneration. Seeds and saplings do not do well in saltwater conditions; they will either not germinate or die early. This becomes a larger concern when larger trees start to die. The death of larger trees, and the younger trees that would replace them, leaves large gaps in the tree canopy allowing more light to penetrate to the forest floor. Grass-like vegetation, such as black needlerush (Juncus roemerianus), cordgrass (Spartina spp.), and sawgrass (Cladium spp.), can now start to propagate in these light gaps. Eventually, there will be a few or no trees left, and there will be only be these salt tolerant grass-like species left.
The goal of my doctoral research is to fully understand how saltwater intrusion is altering these systems. This is important to understand, because these floodplain forests provide many beneficial ecosystem services to us. Ecosystem services are beneficial services provided to humans from nature that we do not have to pay for. Some important ecosystem services that floodplain forests provide us with are storm surge reduction, freshwater storage, and nutrient removal. As these systems are lost, so too are the ecosystem services they provide us with. Despite the laws and regulations in place to preserve the Suwannee River for cultural and ecological reasons, it is slowly being changed by forces that cannot be easily stopped. The only thing left to do is appreciate and record things before they change.
Doctoral Advisor: Dr. David Kaplan