To honor the City of Sanibel’s 50th anniversary on Nov. 5, 1974, SCCF is sharing stories throughout the year to celebrate and chronicle our community’s incredible commitment to conservation. Our first story looks at what makes these islands so unique and early conservation efforts.

The story of Sanibel and Captiva’s amazing legacy of conservation begins with what makes these islands unique and how much islanders have dedicated themselves to preserving them for nearly a century.

Without the deliberate and thoughtful intentions of countless islanders and visitors, our chain of barrier islands could have been paved over with a coastal highway and high-rises.

Let’s take stock of our coastal ecosystems, and why they are so special and worthy of our ongoing commitment to protecting and caring for them.

Unique Evolution of Islands

Humans have lived in this area of Southwest Florida since before there was an island of Sanibel or Captiva. Archaeologists estimate that Paleo-Indians lived here 12,000 years ago. 

The offshore sand bar that became the backbone of Sanibel and Captiva began emerging from the sea as little as 4,500 years ago. The islands were formed by sand ridges from the longshore current that sweeps down the islands and the quiet, steady entrapment of sediment by the tangled roots of the bayside mangroves. 

Captiva is just over one square mile in total, and Sanibel is not quite 20 square miles. They are part of a chain of emerald barrier islands made primarily of crushed shell, limestone, and sand mixed with a bit of clay and mud. Sanibel is the southernmost in the chain, which extends 50 miles to the north.

The islands have been host to Calusa Indians, Cuban and Spanish fishermen, homesteading farmers, and rusticating winter visitors. 

Among barrier islands, Sanibel and Captiva are unique. Their natural features, together with a climate that is subtropical in summer and temperate in winter, create unexcelled habitat for a diversity of birds, reptiles, mammals, and aquatic life. 

Sanibel is Southwest Florida’s only barrier island with a significant southern exposure. It formed from a lobe extending from Captiva. Along its south-facing shores, the currents of the Gulf of Mexico deposit countless shells, making it one of the top shelling destinations in the world.

Sanibel is also Southwest Florida’s only remaining double-barrier island, in which two major sets of ridges catch rains to produce an extensive system of interior freshwater. Just beneath the surface, a rain-fed freshwater lens protects the interior wetlands from saltwater intrusion.

Through visionary conservation efforts that began in the 1930s, the islands and surrounding waters still play host to hundreds of species of birds, fishes, mammals, and reptiles. Sanibel’s unique freshwater interior remains largely intact; Captiva retains a historic low-density development, and the barrier chain also includes state lands on North Captiva Island, as well as a state park on Cayo Costa island.

Roots of Conservation

Conservation efforts began in earnest when a group of residents and visitors formed the Sanibel and Captiva Island Conservation Association in 1938, marking the beginning of an enduring legacy that continues to protect and care for our remarkable coastal ecosystems. 

With conservationist and winter resident J.N. “Ding” Darling as chair, the association — which included nearly all island property owners — rallied the state and achieved the island’s first major success in conserving the islands for future generations.

In 1939, the state of Florida declared Sanibel and Captiva as Sanctuary Islands. The hunting of ducks, alligators, otters, and other wildlife would no longer be permitted. The declaration resulted in a sign erected at the entrance to the islands declaring “Welcome to Our Sanctuary Islands.”  

At that time, getting to the islands was limited to a ferry service from Punta Rassa, keeping the threat of development at bay. During World War II, Darling’s efforts — along with other stalwart islanders — led to the establishment of the Sanibel National Wildlife Refuge, a major milestone in preserving the island. 

Without their tireless persistence, the land quite possibly would have been sold to developers who had placed a bid on the bayside property. The acquisition of the wildlife refuge initiated a phenomenal effort that has continued in earnest thanks to community support, and the partnership of the wildlife refuge, the City of Sanibel, and SCCF, resulting in the preservation of nearly 70% of Sanibel.

Following the dedication of the national refuge in 1945, islanders remained committed to protecting natural resources and wildlife. At that time, sea turtles became recognized as one of the most vulnerable species on the islands.

Origins of Sea Turtle Research & Monitoring

In the 1950s, poaching, raccoon depredation, and especially incidental capture in shrimp nets, were significant problems that required intervention. Encouraged by “Ding” Darling, biologist Charles LeBuff launched Caretta Research in 1959, marking another significant conservation milestone that SCCF carries out today. 

LeBuff employed research to learn more about the behavior and ecology of the islands’ nesting sea turtles, and every morsel of data collected provided valuable insight into their population.  

When Caretta Research disbanded in 1992, its marine turtle permit was transferred to SCCF staff, making it the longest-running uninterrupted sea turtle monitoring and research program in the state. 
By 1960, the islands had established a strong ethic of conservation and remained dedicated to their “Sanctuary Island” designation. However, that would soon be threatened as a bridge to the mainland opened a floodgate of challenges.

Next month, we’ll explore the impact of the Sanibel Causeway’s construction in 1963 and the creation of the Sanibel-Captiva Conservation Foundation (SCCF) in 1967. 

All image use permitted by Sanibel Public Library Digital Archive 

SCCF is proud of the partnership role we have played over the last five decades to protect our unique island environment and the wildlife habitat it provides. Please make a generous donation to support our work now and in the future. For more information, please contact SCCF Development Director Cheryl Giattini at 239-822-6121 or cgiattini@sccf.org.

SUPPORT CONSERVATION

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This article includes excerpts taken from Story of the Islands, written by former SCCF Education Director Kristie Anders. Currently being updated by SCCF, the printing of the Story of the Islands is generously funded by the Sanibel and Captiva Islands Association of REALTORS. The Association promotes appreciation and understanding of the ecosystems of the islands, requiring new members to participate in training that includes a program at SCCF. New residents, through the relationship with their Realtor, are better informed about the unique environment on and around the islands.