Control of Pontederia crassipes in Spain
Pontederia crassipes (Pontederiaceae: EPPO A2 List) is one of the world’s most invasive aquatic plants. Native to South America, P. crassipes has been introduced into the EPPO region where it can cause significant negative impacts including blocking water channels, degrading biological diversity, and providing breeding grounds for mosquitoes. A rapid response control was carried out against P. crassipes in the Guadalquivir River in Seville (Southern Spain). Removal was implemented by the regional environmental Council, national security forces and public companies. After its detection, the distribution and abundance of P. crassipes, and the possible source of the introduction was assessed as the basis for selecting a feasible removal method. Plants were scattered across 110 ha. In the control programme, in total, over 1 900 kg (fresh weight) was removed between May and December 2021 by combining manual removal from water using inflatable boats and floating booms, as well as removal from the bank of the water body. In total, the action cost approximately 22 500 EUR. Most biomass (83 %) was removed during the initial control phase (one month). However, most of the efforts and costs (83 %) were incurred in the following seven months, especially for monitoring and follow-up treatments. The rapid response avoided summer growth, and spread and contributed to reduced biomass and control costs compared to that estimated if control had taken place at the end of the summer. The coordinated response of the stakeholders allowed for an effective rapid response.
Sources
García-de-Lomas J, Dana ED, Borrero J, Yuste J, Corpas A, Boniquito JM, Castilleja FJ, Martínez JM, Rodríguez C, Verloove F (2022) Rapid response to water hyacinth (Eichhornia crassipes) invasion in the Guadalquivir river branch in Seville (southern Spain). Management of Biological Invasions 13 (in press).