The effectiveness of management interventions for the control of Spartina species: a systematic review and meta‐analysis

• 1. Spartina species (cordgrasses) have been introduced to the estuaries around Europe, USA, Australia, New Zealand and Asia as a coastal management tool to stabilise mud banks, and through accidental introductions. These mainly non‐native species are highly aggressive in their new environment, and frequently become the dominant plant species, displacing native flora and fauna.
• 2. The majority of organisations managing estuarine environments within the USA and UK have established integrated control programmes to eradicate Spartina spp. These plans can be expensive to deliver and take many years. For example, the Willapa Bay, WA control programme in 2003 had been implemented for over 3 years, but with an annual cost of approximate $2 m year^?1 (～£1.2 m year^?1).
• 3. Through the use of the systematic review process and meta‐analysis, the effectiveness of management interventions (chemical, mechanical and biological) used to control or eradicate invasive Spartina spp. were investigated.
• 4. The effectiveness of glyphosate and imazapyr herbicides at reducing S. alterniflora differ greatly depending upon application method and whether surfactant or wetting agents are used. Cutting combined with smothering is highly effective at reducing S. anglica densities, but its efficacy has not been established for other Spartina spp. Cutting alone increases densities of S. anglica and S. townsendii, while reducing S. alterniflora densities. Biological control, while in its infancy, has the potential to significantly reduce S. anglica densities, while against S. alterniflora it might be of benefit as part of an integrated programme.
• 5. The results highlight the need to establish targeted control programmes, dependent upon the Spartina spp., the underlying site characteristics and the available budget. Where the evidence base is limited or absent, recommendations of further experiments are presented, including a call for improved reporting of site characteristics and experimental methodology, allowing managers to establish whether trial results are applicable to their own sites and therefore limiting the implementation of ineffective management interventions.

Copyright © 2007 John Wiley & Sons, Ltd.