Adapting to the Tide 

When the 209-acre Fruit Farm Creek Mangrove Project—with a $3.3 million price tag—was completed in March of 2023, there were regulatory requirements included in the permits for the project. Located on the north side of San Marco Road between the Stevens Landing condominiums and Goodland Drive, it is Florida’s largest ever mangrove restoration. One regulatory requirement is that the vegetation comes back within five years. Another requires the tides inside the die-off area to look like the tides outside the area and that the tidal flow underneath the road is going back into the area. If those targets are not reached, the state and federal permits and the partners on the project allow for adaptive management to make sure the project goes well.

Well, three years into the process, there’s been some good news and some not so good news.

"The Fruit Farm Creek project, completed in 2023, had two project areas: a 78-acre stressed area (Phase 1B) and a 90-acre stressed area (Phase Two),” said Jamie Wolanin, research biologist with Florida Fish and Wildlife Conservation Commission (FWC). "Since then, Phase 1B has shown remarkable recovery that is apparent in our monitoring data and when you visit the site. Lots of mangrove propagules have come in and new seedlings and saplings have grown. We are excited to see just how well that part of the project has recovered when our monitoring efforts wrap up in 2028.”

Phase Two has not been so successful.

"On the other hand, Phase Two has shown slower recovery since construction was completed,” Wolanin said. "It is the larger and older die-off area, so it is understandable that the mangroves need more time. However, the project team decided that the best way to speed things along would be to complete an adaptive management project that drains residual standing water. Hopefully we see Phase Two start to recover at a faster rate in the next year of monitoring data." 

Initially, adaptive management to Phase Two was scheduled to be completed last fall. Instead, it was moved to June 2026.

"The original plan was to complete the adaptive management work in November 2025,” Wolanin said. "After further discussion amongst members of the project team, we decided to push the start date for this work to the following spring when water levels would be lowest. This makes it easier for our contractor to see the pockets of low elevation that needs to be connected to the tidal creek. We completed construction of the adaptive management project in June. The project team determined the best location for the hand-dug channels to achieve the most drainage and created three main channels, each with branches running east, southeast, and south. In total, the contractor dug approximately 3,000 linear feet of channels measuring four feet wide by one foot deep.”

The cost for the adaptive management was $35,000 and was funded with legislatively appropriated funds from the Marine Resources Conservation Trust Fund. The work was completed by Stantec, a global leader in sustainable engineering and environmental consulting. Marco Island pays nothing for the mangrove restoration project or adaptive management.

"After completing the hand-dug channel construction as adaptive management of the Fruit Farm Creek project,” Wolanin said, "the FWC contracted Stantec to get elevation data so we can track changes in the channels over time.”

In order for the mangroves to take root and grow, tidal exchange is necessary. Throughout the summer, Phase Two floods, but doesn’t drain. In the winter, the area is mostly dry, emitting a foul odor on hot, sunny days.

"Florida has a wet season and a dry season that aligns with water levels at the project site,” Wolanin said. "Severe mangrove die-offs, like the one at Fruit Farm Creek, can have an unpleasant sulfur smell caused by bacteria breaking down organic material in the waterlogged, oxygen-poor soils.”

Wolanin said the poor condition of the soil contributes to the challenges being experienced with the project.  

"Although it was evident that water was draining from the northwest region of the project (Phase Two) during construction of the larger Fruit Farm Creek project, areas of isolated pooled water were observed in low-elevation spots with significant peat collapse. This is common in mangrove forests that have been dead for a long time. The adaptive management project was completed less than a month ago to enhance the connectivity of Phase Two to the main drainage channel. We are actively monitoring the site and capturing drone footage to determine adaptive management effectiveness. This type of adaptive management work was done for Phase 1A in 2012/2013 and helped further restore those mangroves.”

The Phase 1A Wolanin refers to is located on the north side of San Marco, east of Stevens Landing.

The regulatory requirement of the project and language included in the permits is to see 80 percent wetland vegetation cover across the restoration area in five years. Wolanin said it may take longer, but at this point, hand planting mangroves is not expected.

"When doing restoration projects,” Wolanin said, "the permitting agencies often consider recovery parameters to assess the progress of a project. In the case of Fruit Farm Creek, we are monitoring the project’s progression towards 80 percent vegetation cover within a period of five years post-construction. All the monitoring reports to date have been submitted, as required by our permit. Although 80 percent cover is the long-term goal, the project team has determined the amount of time needed for Phase Two to recover will likely take longer than five years due to discontinuous areas of peat collapse, but we do expect to see recovery of mangroves in the areas of slightly higher elevation in that timeframe. We worked closely with the South Florida Water Management District during the recent adaptive management project, and it was determined that planting (mangroves) would not provide a benefit under current site conditions. To maximize resources, we will continue to monitor annual mangrove propagule dispersal and settlement, which we expect will support natural mangrove establishment in areas where seedlings are most likely to survive.”

Providing the adaptive management works as planned, Wolanin feels good about Marco’s mangroves making a strong recovery.

"While the project team set goals for mangrove recovery when the Fruit Farm Creek Mangrove Restoration Project was designed,” Wolanin said, "it is hard to predict exactly how natural systems will respond to the work and how long recovery will take. Overall, the project team considers the project to be on track, especially considering the size and scope of the project. We are committed to monitoring the project closely and taking action when adaptive management opportunities arise. Rookery Bay National Estuarine Research Reserve, the FWC, and all other partners associated with this project are deeply committed to the sound management of mangroves for long-term resiliency of the Southwest Florida coastal habitats that provide ample recreational opportunities and economic benefits to our communities.”