Mangroves: Holding the island together
June 29, 2011
Just recently, nine homeowners on Clam Bayou came before City Council seeking permission to trim 1,725 mangrove trees and 175 buttonwoods to a height of six feet to improve the view of the residents; in their application, they are doing business as “Clam Bayou Neighbors Association."
The trees in question, which are part of an established mangrove fringe, are on 1,700 linear feet of publicly owned shoreline on Silver Key, an area within the Environmentally Sensitive Lands Conservation District.
One of the purposes of the ESLC District is to ensure preservation and encourage enhancement of natural systems. The Sanibel Plan states the “mangrove areas are of such importance to the Island's ecosystem that they must be preserved.”
City Council did not grant the homeowner group's request. The group is now pursuing approval at the state level.
Given that this issue has now come before the public, it may be well to review here just why mangroves are so important to our ecosystem — and why they must be preserved.
True natives, the mangroves are our most valuable coastal resource. They are a biologically complex ecosystem, the link between the land and the sea. The red mangrove — Rhizophora mangle, with its reddish prop roots — buffers the effect of storm winds, waves and floods on uplands, as the water is absorbed into their expanse.
These mangroves stabilize shorelines. The root system slows water flow, facilitating the organic/chemical material deposit of sediment which imparts nutrients that are the basis of the marine food chain. Nutrients such as nitrogen and phosphorus filtered from coastal waters are incorporated into the leaves, branches and root systems and are naturally transferred to the detrital food web.
Food and shelter for most fish species
An estimated 85 to 90 percent of all local commercial and recreational fin fish depend on mangroves for food and shelter. Attached marine organisms also filter water trap and cycle nutrients. Mangroves are the nursery of the sea. They also are valued as rookeries and shelter for wading birds and brown pelicans. Worldwide, mangroves account for the storage of more carbon than almost any other forest on earth.
Florida has approximately 469,000 acres of mangrove forest. Sanibel, with 11,000 plus acres, has nine miles of mangrove shoreline. The propagules of the red mangrove are embryonic root structures that may float for up to a year before rooting. As they root, they form islands such as the ones that can be seen from Wildlife Drive in the "Ding" Darling National Wildlife Refuge.
The City of Sanibel does not allow trimming for view of mangroves on any city owned or managed property, in order to ensure the mangroves' complete range of ecological value. Trimming has a secondary impact to other native plant communities, altering growth patterns. City ordinance 96-07 mirrors the State 1996 Mangrove Trimming and Preservation Act, also restricting mangrove trimming on public conservation lands.
The mangroves quite literally hold the land on Sanibel — and the citizens of this sanctuary island have the Sanibel Plan and the Land Development Code holding us responsible for preventing mangrove trimming on public conservation lands. The Committee of the Islands supports City Council's decision to uphold the Sanibel Plan and the Code.
As always, we welcome your ideas about this and other island issues. Visit the Committee of the Islands' website at www.coti.org, or send us your thoughts via e-mail to email@example.com.