First records of Heteranthera in the Delta del Ebro, Spain
Heteranthera species were first found in the middle of the 1990s in the Delta del Ebro (Spain) and then in 1991 in Poleñino (Huesca). Heteranthera species (Ponteridaceae) originate from the American continent and are annual aquatics producing stolons. They are known for their huge production of seeds and their great ability to colonize crops. In the Delta del Ebro, the species found are Heteranthera limosa and H. reniformis. H. limosa is quoted as invasive in freshwaters in Portugal (Francisca Aguiar, pers. comm. 2005) and in Sardinia (Giuseppe Brundu, pers. comm. 2005) and it is present in France and Italy (HYPPA Database). H. reniformis is also reported as invasive in freshwater in Portugal (Francisca Aguiar, pers. comm. 2005) and is present in Italy (Tutin et al., 1980) and in France (HYPPA Database).
According to a survey done in the Delta del Ebro, Heteranthera spp. have been localized in 101 plots corresponding to 419 ha, which represents 2% of the total surface of rice cultivation in the Delta. Heteranthera reniformis is the most commonly found with H. limosa only representing 23 ha of the infested surfaces. On the left bank of the river, the plant colonizes 101 ha on Deltebre, and the areas of Cava and Jesús y Maria. On the right bank of the river, the plant colonizes 318 ha on Amposta, Sant Jaume d’Enveja and Sant Carles de la Ràpita.
It is considered that control measures should be applied against Heteranthera species in the Delta del Ebro. These measures could include: herbicide treatments with appropriate active substances and timing of applications; cleaning of agricultural machinery following its use in contaminated areas; better organization of farm work (i.e. beginning work with non infested plots); raising awareness of growers to control the plant.
Sources
Llenes JM, Roque A, Taberner A, Taberner A, Matamoros E, Martinez M, Gisbert D (2006) Primera prospección de Heteranthera en el Delta del Ebro. Phytoma España. 178, 52-56
Tutin, TG, Heywood VH, Burges NA, Moore DM, Valentine DH, Walters SM and Webb DA (eds) (1980) Flora Europaea, vol. 5. Cambridge University Press, Cambridge. 452 pp. Heteranthera Ruiz & Pavon, p. 85.
HYPPA Database: http://www.dijon.inra.fr/hyppa/hyppa-a/hetre_ah.htm, http://www.dijon.inra.fr/hyppa/hyppa-a/hetli_ah.htm
Personal communication with Francisca Aguiar, 2005.
Personal communication with Giuseppe Brundu, 2005.