3rd UF Water Institute Symposium Abstract

Submitter's Name Adrienne Smith
Session Name Posters - Nutrient Dynamics and Enrichment Impacts in Aquatic Ecosystems 1
Category Nutrient dynamics and enrichment impacts in aquatic ecosystems
Poster Number 33
Author(s) Christine Wiese,  University of Florida
  Dr. Carrie  Reinhardt Adams,  University of Florida
  Leah Cobb, University of Florida
  Adrienne Smith, University of Florida (Presenting Author)
  Influence of Initial Soil Nutrients and Seedbank on Ruellia Simplex Control and Resulting Native Species Establishment
  We evaluated the outcome of invasive Ruellia simplex control treatments and the influence of initial soil nutrient levels and seedbank contents on resulting native vegetation re-establishment. A field experiment (1.5 m x 1.5m plots) was established in a R. simplex-dominated floodplain forest in Paynes Prairie State Preserve. Glyphosate was applied in either fall or spring at four application levels (0, 1, 2 or 3 applications at 3-month intervals). Vegetation percent cover of each species was recorded pre-treatment and every three months post-treatment. Seedbank and soil nutrient samples were collected from each plot selected for R. simplex control and an additional twelve plots with no R. simplex present. Glyphosate treatments reduced R. simplex cover; season of spray treatments and number of glyphosate applications had no effect on R. simplex cover. Initial soil pH, phosphorus and mg content were higher at sites with initial R. simplex cover compared to sampling areas without R. simplex, but had no effect on R. simplex cover after the first glyphosate treatment. Early (3-6 months post-treatment) re-colonization of native vegetation was affected by initial soil nutrient levels. Total and native species richness increased as initial pH increased. In contrast, total and native species richness decreased as soil ca and mg levels increased. Quality of vegetative cover assessed with FAQWet (Ervin et al., 2006) decreased when initial levels of soil phosphorus, ca, and mg increased. After 9 months of treatments, initial soil nutrient levels had little effect on native vegetation re-establishment. A seedbank assay conducted in fall and spring showed high native and total species richness with little germination of R. simplex seed. We suggest the seedbank has potential for use in native re-vegetation provided that any barriers to native vegetation growth presented by high soil nutrient levels can be overcome.