|PURCELL, M - Commonwealth Scientific And Industrial Research Organisation (CSIRO)|
|Dray, F Allen|
Submitted to: BioControl
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/27/2011
Publication Date: 4/1/2012
Citation: Center, T.D., Purcell, M.F., Pratt, P.D., Rayamajhi, M.B., Tipping, P.W., Wright, S.A., Dray Jr, F.A. Biological control of Melaleuca quinquenervia: an Everglades invader. Biocontrol. 57(2):151-165.2012.
Interpretive Summary: The Florida Everglades have been drain, ditched and de-watered for decades. This has resulted in the loss of much of the ecological values that it generates. This alteration of the habitat has made it easier for species introduced from other countries to invade and establish and push out native plant and animal species. Although efforts are being made to return water to the system in a way that resembles historical patterns, this will not eliminate the problems caused by non-native species. Melaleuca is a particularly problematic invader because was spreading so fast and changing fire regimes, soil elevations, water table depth, surface flows, nutrient mineralization, disturbance regimes, vertical structure of plant communities, recruitment of native species, light availability, and nutrient availability. A two part effort has been made to eliminate stands of this large Australian tree using herbicides and harvesting methods but these effort caused the trees to drop massive quantities of seeds. A biological control project was therefore undertaken to biologically sterilize these trees and make them easier to control. The project has been extremely successful and melaleuca tree are no longer the threat that they once were.
Technical Abstract: A massive effort is underway to restore the Florida Everglades, mainly by re-engineering hydrology to supply more water to the system at appropriate times of the year. However, correcting water flow patterns alone will not restore the associated plant communities due to habitat-transforming effects of invasive species, in particular the Australian wetland tree Melaleuca quinquenervia (Cav.) S. T. Blake (Myrtales, Myrtaceae), which has invaded vast areas and transformed sawgrass marshes into dense, biologically impoverished, structurally altered forest habitats. To address this threat, an invasive species reduction program was launched that combined mechanical removal and herbicidal control to remove mature trees with the release of specialized insects to suppress seed production and lower seedling survival. Melaleuca has now been removed from the majority of public lands while biological control has limited its ability to regenerate and reinvade from nearby infestations often located on privately held lands. This case illustrates how restoration of highly modified ecosystems may require both restoration of physical conditions (here, water flow), and suppression of high impact or transformative invaders, showing well the need to integrate biological control into conservation biology.