By: Rianna Elliott, NFLT Land Management Specialist
Recently, I was asked why to treat for exotic or invasive species on our lands. Most times these plants appear as beautiful additions to our landscape so the need to eradicate them, to most individuals, is a conundrum. The answer can be just as daunting.
Most ecosystems comprise of a basic landscape with specific plants needed for it to thrive. Some are slow growing or need space for this process to occur. On the same hand many animal species need these plants to be there for grazing or habitat.
The definition of an invasive species is a plant that has been brought into areas, and this can happen accidentally or on purpose. These plants are often referred to as “exotic”, “alien”, “introduced”, or “non-native”. In their natural habitat they are limited by their natural ecosystem keeping them in balance either by pests, herbivores, or diseases. So, when these plants enter a landscape where these limiting factors are not present, they flourish and can often grow without bounds leaving the natural plants fighting literally for their lives.
Not all exotics are invasive meaning they are not proliferating. However, for this article I will stick to those that are invasive exotic.
Today, I will use the example of a sandhill ecosystem. A sandhill is an upland, savanna-like habitat with an overstory of longleaf pines, some oak species, but dominated by a grass understory. Usually, this understory is compromised by wiregrass, paw paws, and wildflowers. The soil is well drained and lacks distinct layers. You often find them in the upper peninsula of the state of Florida but prior to European settlement, they dominated the southeast. It thrives on frequent fire intervals for the plant species to seed and thrive. This soil lends itself to many species of plants that, if found there, will compound.
I like to tell the story of the gopher tortoise. I know that the gopher is not a plant, but it has its own story to tell that will lend you an explanation to why we treat these plant species. A gopher tortoise is what we call a “keystone species”. Meaning many other animals and plants require its presence to thrive and succeed in an ecosystem. Upwards of 250 other animals need not only the burrow but the remains of gophers in order to habitat a sandhill. Indigo snake, pine snake, rattle snake, fox, rabbit; they all utilize the burrows. So, the plants for gophers to ingest need to be in the sandhill for them to survive. It is a domino effect.
Take the invasive exotic sweet tanglehead or heteropogon melanocarpus (pictured to the left) as an example. It is a fast growing, fire thriving, exotic invasive species. It will outgrow, dominate, and push out the plants that the gopher tortoise utilizes for its habitation. If you lose one species, inevitably, you will lose them all.
Lose the pawpaw, wiregrass, and blazing star you have lost the food source for the gopher tortoise. Lose the gopher tortoise you lose them all.
So, we must be on guard and ready to treat these plants that will crowd out what “should” be there for the ecosystems to provide. We do this through closely monitored and carefully thought-out controlled means. Sometimes it is through herbicide directed only on the specific plant. Often it is through what we call “mechanical” treatment. This may mean hand pulling or cutting off the plant prior to it being in seed production. It is often labor intensive, but I have never been happier than seeing the fruits of my labor play out by seeing this species diminish and others thrive.