Effects of Soil Chemistry on Plant Germination and Growth in a Northern Everglades Peatland

Vegetation patterns across the Florida Everglades peatland are influenced by anthropogenic gradients in both hydrology and chemistry. These gradients often overlap, making it difficult to isolate specific causes of vegetation change. We examined whether differences in plant communities between the minimally impacted interior and the impacted perimeter of the northern Everglades could be attributed to soil chemistry as opposed to other factors such as hydrology or seed-bank composition. Seedling establishment from soil seed banks collected from interior locations was examined under conditions that reflected either the phosphorus (P)- and calcium-carbonate (CaCO3)-depleted chemistry of the peatland interior or enriched conditions around the perimeter. Three soil moisture treatments were used to increase seed-bank expression. The interior seed bank contained viable seeds of both interior and perimeter taxa, but distinct plant assemblages established in the two chemistry treatments. Perimeter species germinated in both chemistry treatments, but only survived under enriched conditions. Establishment of these species in the interior is likely limited by low P availability. Germination and survival of some interior species were reduced by enrichment, likely due to elevated CaCO3 levels. Protection from both increased P and CaCO3 loads thus appears important to maintain plant communities in mineral-poor remnants of the Everglades.