Why We Need Sand Dunes

by Tonya Bramlage

A struggling Englewood Beach sand dune

Avid local area beach walkers are seeing remarkable scenes of epic and unprecedented proportions. Alarmingly evident are the shore bird and sea turtle nesting areas that have been obliterated, along with the visible absence of usual beach access roads, boardwalks, and parking lots. There are numerous areas of sand piles heaped up on the beaches and a whole lot of conversation about “all that sand.” Beach restoration efforts clearly cannot be devoid of sand dunes and vegetation if the beach is to be truly replenished.
Coastal sand dunes have been formed by the wind over thousands of years. They play an important role in the ecosystems of the gulf coast and contribute to worldwide environmental diversity. Dunes are naturally dynamic, which means that their sands shift in response to storms, waves, and winds. However, this ability to shift and adapt makes the dunes easy targets for the forces of erosion.
If beaches and dune systems do not receive enough essential nutrients, only sparse vegetation will grow on the dunes and no vegetation will grow on the beach itself. Sea turtles are one of the most vital contributors to this beach dune system. Without the turtles, dune vegetation would lose a major source of nutrients, making them less healthy, and prone to increased erosion. Sand does not retain nutrients very well, so it needs the nutrients from turtles eggs in order to grow and become stronger.
When the dune vegetation grows stronger and healthier, the vitality of the entire beach dune ecosystem becomes fortified. Stronger vegetation and root systems help to hold the sand in the dunes and help to protect the beach from erosion. Sea turtles use the beaches and lower dunes to nest and lay their eggs playing a crucial role in dual ecosystems; the beach dune system and the marine system. When the number of turtles on our beaches decreases, fewer eggs are laid on the beaches resulting in fewer nutrients being deposited.
Climate change, land development, invasive species, and tourism directly impact the environmental stability of the dunes. Every part of an ecosystem is important, if one is lost, the rest will eventually follow. Non-native plants compete with native plants such as sea oats, dune sunflower, and the railroad vine often found growing adjacent to dune systems. Because of dune volatility, any lost nutrients contribute to the overall loss of dune vegetation.
There are certain causes of erosion that surpass what is natural. Non-native ornamental plants do not hold back erosion or provide the ecological benefits that native plants do, and if left unchecked, the spread of non-native plants could dominate the dunes and exhaust nutrients intended for native plant dune vegetation.
As the tide rises and falls and the wind blows, shorelines are constantly subjected to erosion and accretion causing the sediments swept away from one place to be deposited somewhere else.
Restoring our damaged beach areas by planting and creating dunelet mounds adds nutrient rich biomass for establishing new bird nesting areas, habitat for other wildlife, and contributes to building back a living shoreline. Living shoreline techniques integrate natural plant and animal communities into designs that help to control erosion and also assist in the maintenance of natural coastal processes. Dune vegetated coastlines help to reduce wave energy and storm impacts, prevent erosion and property loss, trap sediments, improve water clarity, filter pollutants, preserve coastal resiliency, and provide wildlife habitat. Negative impacts to these ecosystems negatively affect humans.
Healthy intact ecosystems are one of our best and most cost-effective defenses against climate change. They not only help ensure the survival of Florida’s rarest and endemic species, but they buffer our communities from storms, provide flood control and freshwater recharge and store carbon. To date, the most well-studied areas are our coastal ecosystems. While there are many unknowns and much research to still be done, especially in our upland ecosystems, there is no question we are seeing the impacts of climate change on our plant and dune communities in Florida.