Opinion of the Scientific Panel on Plant Health on the pest risk analysis made by EPPO on Hydrocotyle ranunculoides L. f. (floating pennywort)

Following a request from the European Commission, the EFSA Scientific Panel on Plant Heath was asked to deliver a scientific opinion on two pest risk analyses made by the European and Mediterranean Plant Protection Organization (EPPO) on invasive alien plants (American skunk cabbage and floating pennywort). The Panel was in particular asked a) whether these organisms can be considered as harmful for the endangered area of the European Community and thus potentially eligible for addition to the list of harmful organisms in the plant health Directive 2000/29/EC, and b) whether the identified management options are appropriate through an evaluation of their efficacy, feasibility and impact.This document presents the opinion of the Panel on Plant Health on the pest risk analysis made by EPPO on Hydrocotyle ranunculoides L. f.H. ranunculoides is a stoloniferous, perennial, aquatic plant, known as floating pennywort. It is native to North America, where it is considered endangered in some areas, but has been introduced and subsequently naturalised in water bodies within a number of European countries, including Belgium, Denmark, France, Germany, Italy, the Netherlands, Portugal, Spain, and United Kingdom (UK). It is reported as invasive in Belgium, the Netherlands and the UK, forming dense mats of vegetation in still and slow-flowing water courses. An important pathway of entry and spread is the intentional introduction of H. ranunculoides through the trade in aquatic plants.H. ranunculoides is considered an invasive alien plant by EPPO and is included on the EPPO Action List (pests which EPPO recommend member countries to consider for inclusion in their phytosanitary regulations), with the entire EPPO region considered an endangered area.In delivering this opinion the Panel conducted a detailed review of the EPPO pest risk analysis provided, using the internationally accepted standard for pest risk analysis for quarantine pests ISPM No 11.The Panel concluded from the available information that H. ranunculoides is invasive, but considered that the key factors that determine invasive behaviour are not identified in the document. Damage is documented only for a limited area of the EC, in the Netherlands and the UK. Further analysis of the factors contributing to invasive behaviour, particularly the effect of water quality, and high nutrient levels (eutrophy), is required in order to confirm the level of risk posed by H. ranunculoides and identify more clearly the areas of the Community at risk.More detailed examination of pathways, including the scenarios by which the trade in H. ranunculoides can lead to the presence of the plant in natural or semi-natural water bodies is also required before the efficacy, feasibility and impact of risk management options can be evaluated.In order to confirm the risk posed to the Community and enable further consideration of management options, the Panel recommends the provision of further data on:(a) the effect of abiotic factors on the establishment, development, reproduction, survival and dispersal of the plant in both the native and introduced range;(b) the population dynamics of the plant in areas where it is present but not invasive;(c) the volume of trade in H. ranunculoides as an ornamental plant entering and moving within the EC, including further analysis of the means by which it can reach natural water bodies;(d) the nature and occurrence of areas within the EC where conditions are favourable to invasive behaviour of the plant. This could be assisted by the combined use of a geographic information system (GIS), such as the Water Information System for Europe (WISE) and more detailed information of the factors, including eutrophication, which favour the establishment of H. ranunculoides;(e) the environmental damage caused by the plant in areas where it is invasive.