William J. Platt

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Effects of variation in fire season on flowering of forbs and shrubs were studied experimentally in two longleaf pine forest habitats in northern Florida, USA. Large, replicated plots were burned at different times of the year, and flowering on each plot was measured over the twelve months following fire. While fire season had little effect on the number of(More)
Disturbances that are strongly linked to global climatic cycles may occur in a regular, predictable manner that affects composition and distribution of ecological communities. The El Niño Southern Oscillation (ENSO) influences worldwide precipitation patterns and has occurred with regular periodicity over the last 130 000 years. We hypothesized that ENSO,(More)
Small-scale variation in fire intensity and effects may be an important source of environmental heterogeneity in frequently burned plant communities. We hypothesized that variation in fire intensity resulting from local differences in fuel loads produces heterogeneity in pine savanna ground cover by altering shrub abundance. To test this hypothesis, we(More)
Savanna models that are based on recurrent disturbances such as fire result in nonequilibrium savannas, but these models rarely incorporate vegetation feedbacks on fire frequency or include more than two states (grasses and trees). We develop a disturbance model that includes vegetation-fire feedbacks, using a system of differential equations to represent(More)
Few hurricanes affect intact stands of subtropical pines. We examined effects of winds in the eyewalls of Hurricane Andrew, where wind speeds were >200 km h−1, on all remaining large mainland stands of Pinus elliottii var. densa (south Florida slash pine) on limestone outcroppings (rocklands) in the everglades region of southern Florida. We measured(More)
Frequent fire is an integral component of longleaf pine ecosystems, creating environmental conditions favoring survival and growth of juvenile pines. This study examined stand structure, species composition, and longleaf pine regeneration in an old-growth tract of longleaf pine forest (Boyd Tract) experiencing long-term (>80 yr) fire exclusion in the(More)
Organisms capable of rapid clonal growth sometimes monopolize newly freed space and resources. We hypothesize that sequential disturbances might change short-term clonal demography of these organisms in ways that promote formation of monotypic stands. We examined this hypothesis by studying the clonal response of Arundinaria gigantea (giant cane, a bamboo)(More)
Pyrogenic plants dominate many fire-prone ecosystems. Their prevalence suggests some advantage to their enhanced flammability, but researchers have had difficulty tying pyrogenicity to individual-level advantages. Based on our review, we propose that enhanced flammability in fire-prone ecosystems should protect the belowground organs and nearby propagules(More)
Despite earlier notions that fungi are not important in wetlands, it is becoming clear that root endophytes are abundant in wetlands and potentially can influence plant community dynamics. Little is known about the effects of wetland degradation on these fungi. We assessed two groups of root endophytes in a degrading marsh in southeast Louisiana that(More)
The effects of pollination, predispersal seed predation, and plant density upon seed production of Astragalus canadensis L. in a tall-grass prairie were studied by experimental manipulation of plant density. Seed production was greater at high than low plant densities; this was inferred to result from differences in pollination success. Predispersal seed(More)