In a survey of 285 land managers in the U.S., researchers found that they spent nearly $4 million dollars per year on control of non-native Phragmites australis on 89,000 ha but few were happy with the results of their control efforts. The goals of most managers were to restore native flora and fauna and improve ecosystem function, but less than half felt they had met those goals. Most organizations cited a lack of personnel and monetary constraints, along with re-invasion of Phragmites and difficulty in accessing populations. The researchers found no correlation between amount spent on control and success in achieving management goals.
So does that mean that Phragmites control is a waste of time and money? Or just that there needs to be more long-term funding of control and monitoring or new techniques developed for control? Research on effects of Phragmites on natural systems shows mixed results. Some studies show changes to benthic fauna and others show few changes. Phragmites is thought to alter nutrient cycling and some hydrological processes. Different populations under different salinity levels and hydrological regimes may vary in their ecological effects. Many control projects receive one-time funding and re-invasion can occur before any significant changes in flora, fauna or ecosystem processes have had time to take place. Biological control is being investigated as a potential option, but because there are native strains of Phragmites australis, it could be difficult to find a biological control agent that doesn’t damage native populations.
The article ends with a cautionary note to land managers to assess what damage they think is occurring before spending money on control and to attempt to increase post-control monitoring.
Martin, L. J. and B. Blossey. 2013.
