Although the exact dates are unpredictable, it is certain that Lemon Lake will dry up possibly several times of year generally in April and in summer. This happens when the balance between rainfall, tidal heights and evaporation are such that the lake level falls concentrating the fish prey in a much diminished pool of water. This increased density of fish attracts aquatic birds in large and spectacular numbers as long as the food holds out. Once the water is gone so are the birds, until another cycle of increased water levels and fish population growth re-occurs. The three photos of the drying lake from this and other years illustrates this phenomenon ending in a cracked mass of mud.
The exact origin of Lemon Lake within Amberjack Preserve in western Charlotte County, FL, is shrouded in mystery since it is such an unusual tidal wetland with a fresh water marsh at the upper/eastern end, and surrounded by scrubby flatwoods. The earliest aerial photo I could find from 1951 shows a lake much like today but with a much larger southern fork of the creek entering from Lemon Bay. Anecdotal personal accounts from early fishermen indicate that boats used to enter the lake, an impossibility today with dense mangroves blocking the way. Why this creek has become so overgrown with mangroves is unclear, but there have of course been many changes in the watershed with removal of most of the forests, increasing siltation, changing water flows and greatly increasing water nutrients. The northern fork of the creek drains Lemon Creek Wildflower Preserve (shown with a yellow line around the perimeter), which was a golf course for many years with great modification of the wetlands and long term spraying of sewage effluents. Yet juvenile tarpon are abundant in the northern fork, possibly in part because of the reduction in water oxygen levels which air breathing tarpon are resistant to more than their competitors and predators.
The avian stars of this show are roseate spoonbills backed up by a host of white pelicans, egrets, herons, ducks, diving cormorants and anhinga and shorebirds. These birds come and go as they please so you never know when they will be present. Spoonbills feed on small aquatic organisms of all kinds caught by grubbing in the shallow water with their unusual spatulate bill. The adults are especially gorgeous with their pink colors based on pigments derived from their invertebrate prey. They often feed in mixed species flocks with little blue herons and blue winged teal. Occasionally other ducks such as these wigeons will be present. Dabbling ducks, gallinules and coots are primarily feeding on aquatic plants such as ditch grass and algae. A variety of other fish eating birds such as cormorants, anhingakaiser, great and snowy egrets catch fish by sight. Wood storks feed by snapping their bills shut on anything which touches their beaks. The white pelicans migrate to FL for the winter from western N America. They feed cooperatively as a flock and encircle fish schools and soar in flocks from one feeding source to another. Large numbers of noisy black necked stilts are present this year; they feed by picking small animal prey from the surface of the water.
It is likely that the fish composition of Lemon Lake has changed a lot since prehistoric times when there was greater tidal flow and no excess nutrients of human origin. Today the high nutrient levels have caused short food chains to be prevalent- namely plants (algae and rooted flowering plants such as Ruppia) directly to herbivorous birds, and algae to small herbivorous fish such as the sheepshead minnow (Cyprinodon) to carnivorous birds. There are of course some other fish in the lake such as carnivorous mosquitofish and herbivorous mullet. The sheepshead minnow is very tolerant of changing temperature and salinity and copes with low oxygen by skimming the surface. It is able to harvest the high productivity of algae stimulated by the nutrients of human origin and deliver a lot of food directly to birds. So even though this is an “unnatural food web” based on anthropogenic pollutants, it is working to the advantage of the birds. Such is not the case for Lemon Bay itself where excess nutrients stimulate algal growth which suppresses bottom growing manatee grasses.
As an aside while hiking around Lemon Lake I saw two green anoles, the native lizard which has been mostly replaced by brown or Cuban anoles. However it appears that these green natives are staging a minor comeback based on a change in their habits to a more arboreal life style. This is a rare instance of a native species making an evolutionary “end run” around an exotic competitor.
Lemon Lake is not only a fantastic place to see water birds during low water levels, it provides a very rare example of how pollution has actually resulted in a beneficial result rather than an ecological disaster.