Effects of shrub encroachment and removal on South Texas coastal prairie flora

Watson, Parker Alex, Effects of shrub encroachment and removal on South Texas coastal prairie flora. Master of Science, December, 2015. 60 pages, 14 tables, 11 figures, 47 references, 5 appendices. Native-invasive honey mesquite (Prosopis glandulosa) and huisache (Acacia farnesiana) are aggressively encroaching onto South Texas coastal prairies, outcompeting Gulf cordgrass (Spartina spartinae) and associated prairie vegetation with potential legacy effects on the landscape. To measure conditions in the presence of shrubs, data loggers were installed for 16 mos in shrub understories and grass cover to monitor light, soil and air temperatures. Vegetation and canopy surveys were also conducted to evaluate grass cover in the presence shrubs. Data show differences between shrub understory and grass cover maximum temperatures, and that higher shrub cover generally leads to lower grass cover. Regrowth of Gulf cordgrass in small, medium and large bare patches after shrub removal via mechanical, prescribed fire and herbicide treatments used singly or combined was also examined. Results indicate all three treatments used together are most effective for reducing shrub resiliency and the amount of time needed for natural prairie revegetation