Mammals of Gulf Hammock, Levy County, Florida

Abstract

The following report is that of a regional study which contributes to the knowledge of Florida mammals.* The tract known as Gulf Hammock is one of the most undisturbed forest areas in northern Florida. This area borders the Gulf of Mexico between the coastal towns of Cedar Key and Yankeetown, which are shown on map 1. Investigation of the region was conducted twice monthly between June 1949, and May 1950, and during the entire summer of 1950. The area lies at an elevation of less than 25 feet above sea level. Limestones and dolomites of Eocene form the solid bedrock which is mantled with Pleistocene deposits and organic soils. The soils are at most only a few feet in thickness and they become saturated during seasons of heavy rainfall. The entire area may occasionally be inundated. Rainfall is unevenly distributed throughout the year, with the period from June through September being the time of heaviest precipitation, while November, April and May are the months of least precipitation. The extensive forest canopy modifies the effects of wind and temperature to a considerable degree. The major streams in this low, slightly undulating area are the Waccasassa River and Dry Creek. The Waccasassa River has many tributaries, some of which are indicated on map 1. Intermittent drainage areas, locally known as sloughs, vary considerably in the periods they remain flooded but none is flooded continuously. They have thick deposits of organic soils and they are dominated by hydrophytic forest communities. The streams exhibit wide variation in the amount of water carried and therefore the adjacent areas are subjected to periodic floodinlg and excessive drying. During periods of heavy and continued rainfall the Waccasassa channel is unable to handle the water it receives from its system and so backs up and submerges the low areas. Evidence gathered from local residents indicates that nearly the entire study area (fig. 1) was submerged after the hurricane of September 1950. During months of little or no rainfall the opposite extreme exists. Most of the surface drainage of the study area becomes stagnant and ceases to flow and the interstream areas are thoroughly dried out. The vegetation was examined in the study area indicated on map 1. The nomenclature for the plant communities has been adapted from the works of Laessle (1942) and Swindell (1949) and in general, the stages of succession described for Welaka in Putnam County, Florida, appear to be pertinent in Gulf Hammock. The factors which appear to have the greatest effect on the vegetational associations are the depth of soils above the calcareous bedrock, the length of time the soils remain saturated or flooded, the lumbering activities, the effects of the semi-wild cattle and hogs and.of native animals. The