Effects of invasive, non-indigenous plant species on ecosystem processes: Lessons from Florida

Individual plant species that modify ecosystem properties have traditionally been thought to be uncommon in natural systems. I hypothesize that many invasive nonindigenous species do alter these properties at several scales. The non-indigenous plant species in Florida considered the most invasive by the Florida Exotic Pest Plant Council are examined for this capability through review of the available literature. Out of 31 species total, 12-20 (39-64%) potentially alter the ecosystem properties of geomorphology, hydrology, biogeochemistry, and disturbance. When population-level properties that indicate superior competitive ability of the invading species are examined, 13-24 (42-77%) of the species are included, with the majority of species showing traits capable of modifying natural systems at both ecosystem and community/population scales. This review suggests that ecosystem alteration may be relatively common among invasive non-indigenous species. However, much of the current information is anecdotal. Empirical studies directly examining the effects of species on ecosystem and smaller-scale processes are necessary, and highly invasive species may be particularly appropriate for such research. Further, as non-indigenous species homogenize the global flora, they may also homogenize the local flora by increasing the representation of ruderal species. Where ecosystem processes have been altered, site restoration likely will require both control of the invader(s) and recovery of processes.