SCCF’s Wildlife & Habitat Management team is still noticing changes and effects on flora and fauna on Sanibel due to Hurricane Ian in 2022.

Not only are some wildlife species absent from areas they were pre-hurricane, such as the lack of gopher tortoises (Gopherus polyphemus) on the Dayton Tract, but other species have spread around the island, like the exotic invasive Peter’s rock agama (Agama picticauda).

Plants have also been moved around the island from storm surge seed dispersal. Cattails (Typha domingensis) have been popping all over the island in wetlands that never had them. These are being treated in some areas, so they do not dominate wetlands with rare wildlife species that need open bodies of water.

Invasive Buttonwoods Showed Damage Early

Buttonwood (Conocarpus erectus), a Sanibel native tree, has become invasive in many areas due to the lack of natural fire regimes and changed ground hydrology.

“These were one of the first trees to experience high mortality shortly after the hurricane from the storm surge,” said  Wildlife & Habitat Management Director Chris Lechowicz. “They grow in wetlands and transitional wetlands  — the area between uplands and wetlands —that took on and held a lot of saltwater from Ian.”

There were so many areas on the island dominated by buttonwood that the damage was very noticeable. However, some tree species take longer to show the effects.

One of the more common and truly native Sanibel trees — the gumbo limbo (Bursera simaruba) — is the latest to show post-Ian issues around the island.  

High Winds Now Knocking Over Gumbo Limbos

“In the past few months, we’ve noticed that they are falling over, especially during heavy storm events,” said Lechowicz. “A closer look at the fallen ones shows that the root systems and base of the trees have rotted out due to prolonged saltwater intrusion.”

The high winds this summer during storms pushed the trees hard enough that the rot gave away. This species tends to grow in uplands but is also found in transitional wetlands that took on excessive salt water.

“So far, gumbo limbos seem to be the most affected tree species currently, nearly two years after the hurricane,” said Lechowicz. “It’s possible that other tree species might have similar damage but could take longer to show effects.”

The impact of saltwater intrusion on trees is part of the reason why Sanibel was mostly a grassland historically. Periodic storm surge events would cull many of the trees that survived natural fire events. Salt-tolerant grasses would quickly recover after these events.