Distribution and Abundance of White-Tailed Deer in the Florida Everglades

Fleming, D. Martin; Schortemeyer, James; Ault, John

The large size of white-tailed deer, their role as a major herbivore in the Everglades, as well as significant and well publicized die-offs related to high water conditions and their importance as a key prey base for the endangered Florida panther have focused attention on the Everglades deer herd. However, no data are available on the relative distribution and abundance of deer in the Everglades in relation to systemwide landscape patterns and temporal characteristics. Objectives of this study, therefore were to (I) document seasonal and annual changes in their relative distribution and abundance systemwide (2) identify environmental correlates influencing the distribution and abundance patterns observed with particular reference to hydrologic parameters and (3) assess changes in deer distribution and abundance in response to intensive, regional water management regulation initiated in the early 1960s. Systematic aerial surveys were conducted over the freshwater, interior wetlands of the system during the wet (August/September) and late dry season (May/June) months from 1985 -1989 to document deer distribution and abundance. Annual productivity estimates (number of fetuses per adult doe) from harvested does in the northern Everglades and annual recruitment indices(number of 3+ month old fawns in population) for the entire study area were also obtained during this study period. Highest average densities of deer observed occurred in wetlands characterized by seasonal water level fluctuation and intermediate hydroperiods. Estimated average breeding date occurred on 30 July, and ranged from 26 July to I August. Estimated breeding dales of individual deer (n=69) ranged from 13 May to 10 September. Annual average productivity over the study period was 1.18 (n=69) and ranged from 1.0-1.33. Annual productivity was related to average marsh water depths during the gestation period(September-January). Peak fawning was well synchronized with seasonal changes in the hydrologic regime and occurred during the middle of the dry season (february/March), at a time when numerous dry sites are normaily available for fawning. fawn survivorship was inversely related to average marsh water depths during the fawning season (January-May) of each study year in drainage basins with pronounced seasonal water level fluctuations. In such drainage basins, total numbers of deer fluctuated in relation to seasonal and annual changes in marsh water depths. Comparison of deer herd population estimates from this study with those of previous studies conducted in the 1950s suggest that a major reduction in deer numbers within the northern Everglades has occurred. Environmental factors believed related to this decline, including wetland drainage and impoundment associated with intensive. regional water management practices initiated in the 1960s. are discussed along with critical hydrologic restoration elements.