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Enhanced Ecological Succession Following Phosphate Mining

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The Florida Institute of Phosphate Research funded a three-year research project to the Center for Wetlands, University of Florida, entitled “Enhanced Ecological Succession following Phosphate Mining.” The primary goal of this research project was to accumulate data necessary to develop practical (e.g., cost effective and applicable on a large scale) methodology and technology for reclaiming phosphate surface-mined lands to native forested ecological systems as one of many viable reclamation alternatives. To achieve this goal, research was directed toward identifying components essential for enhancing development of native forest ecosystems. Certainly, it could correctly be argued that almost all components in ecosystems are essential. However, is it possible that there may be some components more important or essential for establishing ecosystems with the additional ecosystem complexity contributing to long-term ecosystem maintenance? Can we increase the rate at which ecosystems develop (i.e., enhance ecological succession) by actively introducing some of these “essential” ecosystem components? Research in this project focused on four “essential” components that may enhance reclamation to native forest ecosystems.

The “essential” ecosystem components tested were (1) a multispecies mixture of seeds, (2) mycorrhizal fungi symbionts, (3) soil nutrients, and (4) an organic base (such as, straw or hay mulch, or wetland organic soil for wetland areas). These components were tested individually and/or in combination in greenhouse studies, microplot experiments, and at several reclaimed mined sites. The ambitious ultimate goal of the project was to develop a field application method for direct seeding a multiple species seed mixture with a composite of beneficial mycorrhizal fungi. However, much preliminary research was needed to reach this ultimate goal. Therefore, several paths of research were conducted simultaneously. Studies were conducted on plant community succession and mycorrhizal colonization of unreclaimed sites of different ages to determine rate and success of natural invasion of woody plants and their mycorrhizal fungal symbionts to these areas. The effectiveness of using a “broad spectrum” mycorrhizal fungi and/or mycorrhizal fungi isolated from mined soils on growth of select woody plants was investigated. Seeds of native woody plants were collected and stored for use in greenhouse and field experiments. Field plots were studied to assess number and survival of directly seeded plants. A field application method of direct application of seeds and mycorrhizal fungi was also tested and refined.