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Seasonal wetlands have high variability in the timing, depth, and duration of flooding. The timing of hydroperiod relative to reproduction may be especially critical since reproductive timing may be constrained by other factors. Pomacea paludosa (Florida apple snail) is a large, aquatic snail that tolerates a range of hydroperiods. This study compared P. paludosa reproduction in depressions in natural (N=20) and restored (N=60) seasonal wetlands (wet 6 to 8 months) in the southern Everglades for five years. The total number of egg clusters in a year ranged from 260 to 621. Restored sites always had fewer egg clusters per year (mean±standard error of 54.6±4.8 to 64.2±23.1) compared to a natural site (207.0±38.4). Peak oviposition occurred after the onset of the wet season, typically in July, and then decreased approximately two months later even though similar surface water levels occurred. Compared to long hydroperiod wetlands, the average number of eggs per cluster was lower and reproductive timing shifted from the non-rainy/dry season to early wet season. A combination of hydrological characteristics appeared to influence the timing and amount of oviposition. Moreover, functionality of seasonal wetlands in the southern Everglades may change depending upon cumulative hydrological conditions over several years.

No abstract

This article describes the natural re-establishment of south Florida slash pine (Pinus elliottii var. densa) on former farmlands within Everglades National Park. Restoration of these farmlands involves removal of all existing vegetation and underlying disturbed soils, followed by natural recruitment-there is no planting or seeding. Four years after restoration, 3,013 seedlings greater than 4 inches (10 cm) in height occurred on the 31-acre (12.5ha) site. The majority of seedlings were within 82 feet (25 m) of an undisturbed rockland pine habitat and at elevations of 3.5 feet (1.1 m) or higher. Ground elevation affected both mortality rates and growth. Seedlings at lower elevations had higher mortality rates and slower growth rates during the first three years. Hydrological conditions, which are related to ground elevation, appear to affect pine seedlings in two ways. First, surface water tends to cause higher mortality of recently germinated pine seedlings at lower ground elevations and slow the initial growth of the surviving seedlings. Second, at higher elevations, the depth to the water table appears to limit germination.