Inter-basin water transfers and the expansion of aquatic invasive species

Abstract

Inter-basin Water Transfers (IBWT) are recognized as one of the major pathways of freshwater invasion. They provide a direct link between previously isolated catchments and may modify the habitat conditions of the receiving waters such that they become more favourable for the establishment of invasive species. Combined, IBWT and invasive species will intensify the stress upon native species and ecosystems. Using the Severn and Thames Rivers-two of the largest river systems in Great Britain—as a case study, here we assess the potential influence of IBWT on the expansion of invasive species and thus their impact on biodiversity conservation. The Thames Valley is subject to extensive water abstraction, and an increasing population means that supplemented flow from the River Severn is being considered. Multi-scale Suitability Models, based on climate and water chemistry respectively, provided novel evidence that there is serious risk for further spread of invasive species in the focus area, particularly of the quagga mussel, a recent invader of the Thames River. Native freshwater mussels are particularly vulnerable to changing environmental conditions, and may suffer the decrease in alkalinity and increase in sedimentation associated with an IBWT from the lower Severn to the upper Thames. Regional models suggest considerable overlap between the areas suitable for three vulnerable native freshwater mussels and the expansion of invasive species that negatively impact upon the native mussels. This study illustrates the use of novel spatially-explicit techniques to help managers make informed decisions about the risks associated with introducing aquatic invasive species under different engineering scenarios. Such information may be especially important under new legislation (e.g. EU Invasive Species Regulation No 1143/2014) which increases the responsibility of water managers to contain and not transfer invasive species into new locations.

Invasive species influence macroinvertebrate biomonitoring tools and functional diversity in British rivers

“…Great Britain has become increasingly affected by aquatic invertebrate invaders originating from the Ponto Caspian region (Gallardo & Aldridge, 2013a, 2013b, 2015). The extensive network of river channels and canals in the United Kingdom, coupled with inter‐basin water transfers, have been recognised as migratory pathways that may have directly facilitated the internal dispersal of D. haemobaphes (Johns et al., 2018) and other invasive taxa (Gallardo & Aldridge, 2018).…”

Forecasting the future establishment of invasive alien freshwater fish species

“…Freshwater ecosystems are particularly useful for studying invasion pathways of invasive alien species, as their dendritic nature means that well-defined pathways between two points often exist (Fagan, 2002). Hence, when a species has been introduced at one location, avenues for further establishments up or downstream can be identified, preventing both invasion and its associated management costs (Keller, Frang and Lodge, 2008;Gallardo and Aldridge, 2018) (establishments which occur as a result of spreading from an introduction at a connected location will henceforth be referred to as secondary dispersal).…”

Development and characterization of 14 novel microsatellite markers for an invasive goby ( Tridentiger bifasciatus ) in water transfer system

“…Inter‐basin water transfer projects (IBWTs) have been recognized as one of the major pathways of fish invasions by connecting previous isolated donor and recipient drainage basins (Meador, 1992). Knowing the origin of invasive species, its dispersal process cross the geographic range and population demographic dynamics plays significant roles in evaluating invasion risk (Schmidt et al., 2019), predicting potential distribution (Gallardo & Aldridge, 2018) and understanding invasion mechanisms, particularly related to water diversions. Studying the genetic patterns among populations by neutral molecular markers is widely used to reconstruct invasion history containing such aspects (Estoup & Guliiemaud, 2010; Cristescu, 2015).…”