Mangroves and mollusks

Tuesday, February 21, 2012 FORT MYERS, FL – We took a nature cruise at the conservation area on the north side of Sanibel Island today. It confirmed that having a knowledgeable person explain the flora and fauna of an area sure beats exploring with an unschooled eye. We figured that after the holiday weekend, the traffic would be thinner. Wrong! As we crawled along, we dropped the idea of visiting one of the beaches before checking in for the cruise. We learned that it was best to arrive before eight and leave after seven to ensure an easy ride. Also, renting a bicycle would also be a much better way to get around than driving. The “Ding” Darling wildlife refuge bears the name of its founder, J.N. Darling, who began establishing a protected area for wildlife on Sanibel Island in the 1940s. He was first known as a controversial political cartoonist, but now his name, and nickname, lives on in the 6,400-acre preserve that teems with birds, plants and animals. Our tour began indoors where our guide Jessica described how sea creatures survive, and what species are most common in this area. At a watery “touch table” we were allowed to handle conch shells that still housed their snail-like inhabitants, and live sea stars – not starfish, because they are not fish. We then climbed aboard a large pontoon boat for our tour of Tarpon Bay on the north side of Sanibel Island. Jessica steered us toward some small islands covered with mangrove trees. They were made when people in early times left dredged-out material in the bay instead of removing it. Mangrove twigs from other plants latched on and began to grow. The trees provide an excellent habitat for birds to nest where predators can’t harm them. As we passed the islands, we saw dozens of huge pelicans and herons perched in the trees. Some were building nests and performing mating rituals. The white pelicans, Jessica said, have the second-largest wingspan of any bird in the US, after the California condor. Mangroves are uniquely adapted to growing in salt water, with finger-like roots that have special openings for absorbing oxygen. This happens only when low tide exposes the openings, so they have only a small period of time to absorb oxygen. In addition, each plant has certain “sacrificial” leaves that collect salt water absorbed during osmosis, turn yellow and drop off the plant. Amazing! As we headed back, we caught sight of something black in the water at some distance. Jessica identified it as a manatee, but it never resurfaced. We also saw what looked like two dolphins’ dorsal fins, but our excitement abated when, minutes later, two stingrays drifted past. Their wings, breaking the surface, sure looked like dorsal fins! In any case, we had learned a lot and enjoyed our outing immensely. After our tour, we made it to the beach on the other side of the island. It was great to stroll in the foaming surf and admire the thousands of shells, mostly small or in pieces, strewn on the shore. Sanibel is a shell collector’s paradise, but it takes a keen eye to locate intact ones of any size. They are much more abundant after a storm, when bigger waves carry large undamaged specimens onto shore. When I went to rinse my beach shoes in an incoming wave, I saw the wings of two stingrays just a foot or two away in the murky water! No wonder wise waders use the “stingray shuffle” to avoid stepping on such creatures.