Ecology and Environmental Impact of Myriophyllum heterophyllum, an Aggressive Invader in European Waterways

Abstract

The submerged evergreen aquatic plant Myriophyllum heterophyllum is among the worst invasive species in Europe, causing severe problems especially in navigation channels but also lentic systems. This review aims to provide a comprehensive overview and update on the current distribution and risks associated with this species in Europe and elsewhere. We provide an evaluation of current identification keys since misidentification can underestimate the extent of its spread. In addition, hybridization with other milfoil species has been reported in North America but seems unlikely in Europe. We further describe in detail the ecology, specifically resource requirements and biotic interactions with other plants, herbivores and pathogens as well as the spread potential of the species. Good knowledge of the autecology and synecology of this species should allow some conclusions about environmental factors possibly related to its invasive growth and is mandatory for the preparation of species-specific management measures. Finally, we outline the status of regulations coming into effect in member states of the European Union (EU) and provide an overview of applied and potential management practices.

Hydrocharis laevigata in Europe

“…Such is, above all, the result of eutrophication, but other causal factors include changes to hydrological regimes (i.e., reduced levels of water flow), decreasing degrees of water transparency, and global warming, which are simultaneously transforming natural aquatic environments [ 5 , 48 , 49 , 50 , 51 , 52 , 53 ]. These ecological shifts are harmful to native aquatic plant populations while promoting the establishment of invasive species such as H. laevigata , leading to profound transformations in European ecosystems [ 12 , 14 , 54 , 55 , 56 , 57 ].…”

Climate change may exacerbate the risk of invasiveness of non-native aquatic plants: the case of the Pannonian and Mediterranean regions of Croatia

“…Additionally, in Croatia, M. heterophyllum was recently found in the Mediterranean Region on the Island of Krk (north-eastern Adriatic) in Lake Ponikve (Starmühler 2009;Jasprica et al 2017), as well as in the River Neretva Delta (Jasprica et al 2017). It is likely that both species can spread rapidly due to their fast uncontrolled growth and propagation by fragments (Gérard et al 2014;Gross et al 2020). Both L. peploides and M. heterophyllum are tolerant of a wide range of temperatures, substrata, and water quality (Matrat et al 2004;Hussner and Jahns 2015).…”

Socio-ecological impact of monogenetic volcanism

“…Limnological changes imposed by volcanism limited life on aquatic organisms in the short term, but Gloeotrichia played a signi cant role as pioneer in phases of poor nutrient availability 42 , spreading fast perhaps due to xing nitrogen and the high availability of phosphorus. These conditions were also favourable for the macrophyte Myriophyllum, which grow in waters with high nitrogen content and phosphorus availability 43 and prefers acidic waters 44 (shallow lake phase in Unit 2a, Fig. 2).…”