FRESIS · Freshwater invasive species in Europe: control, prevention and eradication

Freshwater invasive species in Europe: control, prevention and eradication

Project context and objectives Biological invasions coupled with climate change are currently the greatest threat to biodiversity worldwide and to the ecological and economic well-being of society. According to the European project DAISIE (2009), up to 11 000 species have invaded Europe resulting in native biodiversity loss, changes in ecosystem structure and function and alterations of disturbance regimes. Invasive species also have major economic, agricultural and health impacts, which has been estimated to amount at least EUR 12 billion each year. Moreover, if not prevented or controlled, these costs may multiply in the future as some of these species expand their area of distribution in response to climate change. Yet little is known about the distribution and impacts of freshwater invaders in Europe. The main objective of the EU-funded FRESIS project is to improve the knowledge of ecologically and economically important freshwater invasive species at a European scale. Within this framework, multiple modelling techniques have been used to assess the risk of establishment and spread of aquatic invasive species into European freshwaters. Project results 1. Risk assessment of the killer shrimp, Dikerogammarus villosus, in Great Britain: in this study we used a combination of techniques to assess the general risk of invasion by the aquatic invader Dikerogammarus villosus in Great Britain. First, bioclimatic models (Support Vector Machine algorithm) showed that nearly 60 % of Great Britain shows the minimum bioclimatic suitability for the species, particularly southern and eastern England. Moreover, the northern part of the Ouse catchment (including two relevant Ramsar sites), is at serious risk of being invaded in less than five years by natural drift. Considering the high climate suitability of broad areas of Great Britain to the species, the current spread of other Ponto-Caspian species, and the high natural and artificial connectivity of the hydrological network, we conclude that D. villosus is very likely to continue its spread in Great Britain, dramatically affecting the native biodiversity. 2. Combined threat of climate change and invasive species on endangered native species: climate change and invasive species are two major biodiversity threats expected to cause major species' extinctions in the future. In this study, we evaluated the joint threat posed by climate change and invasive species on the distribution of endangered freshwater species. The 2050A scenario suggests the zebra mussel (Dreissena polymorpha) may strongly benefit from climate changes (+44 % range size), while the range of the depressed river mussel (Pseudanodonta complanata) experiences an important reduction (-32 %). 3. Priority setting for invasive species management: Ponto Caspian species in Great Britain: invasive species drive important ecological and economic losses across wide geographies, with some regions supporting especially large numbers of non-native species and consequently suffering relatively high impacts. For this reason, integrated risk assessments able to screen a suite of multiple invaders over large geographic areas are needed for prioritising the allocation of limited resources. A climatic 'heat map' combining the results of 16 Ponto Caspian aquatic species shortlisted as potential future invaders of British waters pointed to the SE of England as the area most vulnerable to multiple invasions, particularly the Thames, Anglian, Severn and Humber river basin districts. Regression models further suggested that alkalinity concentration > 120 mg/L in SE England may favour the establishment of Ponto-Caspian invaders. Project conclusions By modelling the specific conditions of the known distribution of an invader, we can locate areas at large scale most likely to be successfully invaded if provided with propagules. Although modelling techniques have been traditionally used with terrestrial species only, we demonstrate their great utility to prevent the introduction and spread of freshwater invasive species at large scales. Invasive species have a high ability to adapt to new environmental conditions and are therefore more likely to cope - probably even benefit - from climate changes. This will involve their geographic expansion towards northern latitudes, and increased pressure on endangered native species whose phenotypic flexibility is poorer. Distribution models assist in management of endangered species over large spatial and temporal scales by identifying current and future areas of shared bioclimatic suitability and potential refugia. Species modify their habitat making it more suitable to other invasive species, eventually leading to an ‘invasional meltdown’. The production of integrated risk maps for future invaders provides a means for the scientifically-informed prioritisation of resources towards particular species and geographic regions. Such tools have great utility in helping environmental managers focus efforts on the most effective prevention, management and monitoring programmes. Socio-economic impacts Invasive species have numerous multilevel impacts which go far beyond ecosystems, with notable effects on societal well-being, including human, animal and plant health, the production of foods, fuel and fibre, and the regulation of vital processes including climate, water quality, soils and pollination. The overall economic costs of aquatic invasive species in Europe is estimated in EUR 12billion per year, while in Great Britain alone it has been recently estimated in a total of 1.7 billion pounds sterling. The EU-funded FRESIS project is contributing to reducing these costs by locating areas under a highest risk of invasion, flagging species of special concern should they establish widely, and evaluating how the interaction between invasive species and climate change may affect the conservation of native species and habitats. This project is especially relevant to environmental practitioners, public and private environmental entities, and researchers interested not only on invasive species but also in the use of statistical predictive techniques. We believe this research has great use in helping environmental managers focus efforts on the most effective prevention, management and monitoring programmes.

Текст от CORDIS, на английски · Данни: CORDIS, © Европейски съюз