First report of Pontederia cordata in Southern Spain
Pontederia cordata (Pontederiaceae) is an emergent, aquatic, long-lived perennial plant species native to the Americas. The species has been introduced to a number of regions worldwide as an ornamental species. The species is invasive in parts of Australia and reported as an emerging invasive species in South Africa. In the EPPO region, P. cordata has been recorded previously in Spain as a casual in the northeast of the country. It has also been recorded in Belgium, France, Ireland and the Netherlands. The new record in the south of Spain was recorded in June 2019 in a freshwater stream near the city of Dos Hermanas (Seville, Southern Spain). Here, the population formed a dense mat and included flowering and fruiting individuals, covering an area of 100 m2. Globally, P. cordata colonises marshes, streams with standing water, ponds and shallow lakes. In South America, it is also found as a weed of rice fields. The species invasion risk for P. cordata in Europe was assessed using the Australian Weed Risk Assessment which resulted in an overall score of 25 (species with a score of > 6 have a high invasion risk). The high score from the weed risk assessment is due to several characteristics related to the species, its invasion process and potential impact. For example, the climatic similarity of the native and potential alien range, the weedy behaviour of the species in agricultural and natural areas, and the repeated history of introductions in waterbodies in temperate regions of the world. Additionally, the fact that the species produces viable seeds which are relatively easy to propagate, and that vegetative reproduction is possible, and propagules are easily dispersed adds to the high score. P. cordata exhibits a high potential to become invasive in Europe and populations of the species should be monitored and where they occur in the natural environment eradication measures should be applied.
A new global distribution map has been added to EPPO Global Database: https://gd.eppo.int/taxon/POFCO/distribution
Sources
Dana ED, García-de-Lomas J, Verloove F (2021) First record of Pontederia cordata L. (Pontederiaceae) in southern Spain and risk assessment for Europe. BioInvasions Records 10(4), 775– 788. https://doi.org/10.3391/bir.2021.10.4.02