| Field studies on phosphate-mined lands were undertaken to evaluate several paradigms for explaining succession, including inhibition, initial floristics, relay floristics, coevolution, and self-organization. Primary objects of study were wetland seed bank formation, formation and stability of wetland macrophyte communities, interactions between colonizing species and trees on upland sites, and the role of mound-building ants in upland succession.; A survey of natural and post-mining wetlands showed seed banks develop rapidly, but contain only wind-dispersed early successional species. Late successional marsh species can be added as an instant seed bank through muck material from a donor or, in some cases, by planting.; The development of a reclaimed marsh was monitored over its first four growing seasons. Results showed that while very different plant communities developed with the application of muck from a donor marsh as compared to natural succession, both types of initially established macrophyte communities remained stable throughout the monitored period.; Upland succession was enhanced with direct seeding and seedling transplants in four treatments: natural colonization, enhancement of natural colonizers, enhancement with legumes, and weeding. Tree seedlings had better height growth in plots in which the colonizing weeds were removed. Tests indicated that the five paradigms investigated operated concurrently during primary succession.; Fire ants (Solenopsis invicta) were the most commonly observed invertebrate species on mined lands, with well-established populations within the first year after mining. Mound densities on 1- to 5-year old sites ranged from 560 to 2,000 per hectare. Mound soils had higher concentrations of sodium, potassium, total nitrogen, and organic matter than the adjacent non-mound soils. In greenhouse experiments, a grass and a woody plant exhibited enhanced growth on mound soils. Water infiltration rates were 5 to 100 times greater on mound soils than non-mound soils.; The view of the competing paradigms as mutually exclusive was not supported. A unifying paradigm may be possible from a more eclectic synthesis of the inhibition, initial floristics, relay floristics, coevolution, and self-organization models. |
