Ecological Notes on Seasonal Depression Marshes in Southeast Florida, with Special Attention to Soil Modification and Interspecific Facilitation by Hypericum fasciculatum (Clusiaceae), a Woody Shrub

Depression marsh intra- and interspecific facilitation in Southeast Florida, dominated by Hypericum fasciculatum, Stillingia aquatica, and Rhynchospora tracyi were studied as a third installment to the author’s ongoing interest in “Hypericum-Stillingia (HS) marsh” vegetation. The project includes a contextual overview in relation to the HS marsh environmental filter, stress-gradient-hypothesis, and harsh-habitat trait convergence vs. divergence. Using field measurements, transects, and quadrats, the effort focused mainly on two research questions: 1. Does the Hypericum fasciculatum microdistribution relate to marsh microtopography? 2. Does H. fasciculatum have positive or negative associations with other species? Tempered by “cause and effect” concerns, the results supported positive feedback autogenic site alteration by H. fasciculatum along with interspecific facilitation.