A Review of Spartina Management in Washington State, US

Management of non-native Spartina plants including Spartina alterniflora Lois., Spartina anglica C. Hubb and Spartina patens (Ait.) Muhl. in Washington State, U.S. evolved during the 1990s from small-scale field trials to a large-scale integrated pest management program. The development and implementation of the program were significantly hindered by stakeholder conflict, particularly regarding the use of herbicide in estuarine environments. In 1995, Washington State Department of Agriculture was appointed to manage these invasive species. Agency coordination and strategy reviews were undertaken. A wide range of control techniques, including physical removal, mowing and herbicide, were established, with all techniques demonstrating considerable limitations. The combination of mowing and herbicide provided the greatest efficacy but was expensive. Development of biological control options is in progress but will take years to prove effectiveness for Spartina management. Program progress based on existing mapping and efficacy data is difficult to gauge. This program demonstrates that Spartina plants are difficult and expensive to eradicate. Between 1995 and 2000, infestations increased in area by 250%, affecting more than 8,093 ha of intertidal land. During this period, approximately 15% of the infestation was treated annually. Although the program has evolved considerably, substantially increasing knowledge on the management of Spartina, infestations in Washington State continue to present a range of management challenges, including the development of a standardized and integrated mapping procedures, cost-effective control techniques and improvements to stakeholder management.