by Allison Vincent
When you visit the CREW lands you’ll come across invasive plant species, and whether you’re aware of them or not, they’re there! Some invasive species are beautiful, like the caesar weed, and you might find yourself wondering why the land managers have it out for them. What could a few plants possibly do to impact the broader ecosystem?
Let’s begin with a few definitions, because invasive species are best understood by discussing the meaning of native and non-native and their interactions with humans. The scientific community agrees that native species wandered into an area naturally and long ago – some time during or after the mid 16th century at the time of European contact with the unexplored land across the Atlantic – either by wind, sea, birds, animals or other natural factors. As species expand or contract their native territory, they go through a process called “range change”. The native species then go about the process of adapting to the changed ecosystem, which in geographic terms was a feat considering that much of Florida was once the bottom of the ocean.
Non-native species, on the other hand, are introduced to a new environment either intentionally or by accident. The distinction in defining invasive takes non-native issues one step further because invasive species, in addition to being introduced by humans, often pose an environmental or economic threat and may cause harm to humans.
Still, what exactly is so negative about the impact of these invasive plant species, given they all make oxygen and absorb carbon dioxide? These tough questions are outlined by land management professionals who rely on current science to categorize the level of impact invasive species have on lands they manage, like the CREW lands. For instance, some invasive species, like the Melaleuca tree, will overtake wetlands and absorb an inordinate amount of water if not treated, which is exactly why they were brought to southwest Florida – to drain the swamps.
In turn, land managers use mechanical, chemical and biological control efforts to manage the spread of invasives, because without naturally occurring factors that limit their impact – like weather, diseases or insect pests – invasive species can disrupt the balance of the ecosystem they’ve supplanted, often out-competing and displacing the native species. The reduction in biodiversity can adversely impact wildlife and alter natural processes such as fire and water flow, all of which directly affect the human population which relies on those same resources.
Let’s talk more about the unintended impact that invasive species have on human populations, specifically in south Florida. Primarily, invasives threaten remaining wetland environments that provide a freshwater recharge of our drinking water sources in the underground aquifers. Native species have had time to adjust to the particular conditions of the Florida environment, so when the wetland composition goes from a natural state to a place overrun with counterproductive species, some of our basic needs – like water and safe shelter – are drastically affected.
Protecting these wetland areas provides habitat for wildlife that in turn generates billions of dollars a year in expenditures by wildlife enthusiasts, hunters and anglers. The financial benefits of preserving the complicated ecosystems of south Florida are well documented and worthwhile. Without the wetland environment to slow the flow of rainwater so that it can be absorbed into the ground and replenish the drinking water supply in the aquifers, Florida would not be able to sustain its current significant population, much less what we expect to see in the future.
The CREW Project began watershed preservation in the late 80s and the CREW lands will continue to be preserved in perpetuity. Several large scale projects, like the hydrologic restoration project completed at CREW Flint Pen Strand and the ongoing CREW Marsh trails restoration focused on carolina willow, provide visible examples of the land management process you can witness in person on the trails over time. The 60,000 acres of CREW preserve land for water retention, wildlife and all the other ways these important resources overlap. To protect this land and the water it stores for the next generation we all must partner to fund this preservation, to protect it, and to educate everyone about it.