eDNA for detection of five highly invasive molluscs. A case study in urban rivers from the Iberian Peninsula
November
eDNA for detection of five highly invasive molluscs. A case study in urban rivers from the Iberian Peninsula
Laura Clusa 0 1
Laura Miralles 0 1
Ana Basanta 1
Carmelo Escot 1
Eva GarcÂõa-Va zquez 0 1
0 Department of Functional Biology, University of Oviedo , Oviedo, Asturias , Spain , 2 Metropolitan Water Supply and Sanitation Company of Sevilla , EMASESA., Sevilla , Spain
1 Editor: Hideyuki Doi, University of Hyogo , JAPAN
Biological invasions are an important threat to biodiversity especially in aquatic ecosystems, and their frequency is generally higher near urban areas. Potentially invasive non-indigenous molluscs were deliberately introduced into European waters for food (Corbicula fluminea) and biocontrol (Melanoides tuberculata), and unintentionally introduced by ballast water (Mytilopsis leucophaeata, Corbicula fluminea), stock contamination (Sinanodonta woodiana), accidental escapes from aquaculture (Sinanodonta woodiana), aquarium trade releases (Melanoides tuberculata) and even attached to aquatic birds (Corbicula fluminea). Three rivers from the Iberian Peninsula were monitored near the three most populated inland cities to evaluate the presence of these invasive molluscs through PCR amplification using taxon-specific primers from eDNA. New primers were designed within 16S rRNA and cytochrome oxidase subunit I genes, tested in silico from BLAST methodology and experimentally in vitro before application in the field. C. fluminea was found in Ebro River (near Zaragoza); M. leucophaeata in Guadalquivir River (near Sevilla). M. tuberculata and S. woodiana were found from enclosed areas (lake and reservoir respectively) upstream, respectively, Zaragoza and Madrid. The new tools are ready to be used in other regions where these species are also invasive.
Introduction
Biological invasions are one of the most important threats to biodiversity. Particularly in
aquatic ecosystems the number of invasive species has increased in the last decades, due to
globalization and closely related to human activities [
1, 2
]. Human-mediated transport
together with global warming could promote the rapid and uncontrolled dispersion of invasive
freshwater species [3]. An example is the rapid spread of Mytilopsis leucophaeata (native to the
Gulf of Mexico) and the zebra mussel Dreissena polymorpha (native to the Caspian Sea) in the
Baltic Sea [
4
].
The ways of introduction of aquatic species are numerous. Invertebrates are deliberately
introduced for food and biocontrol, and may be also unintentionally released from accidental
aquaculture escapes, ballast water, water connections, hitchhikers, stock contamination, pet
European Commission: EU RIA Contract 689682±
AMBER.
and aquarium trade [
5, 6
]. For example, M. leucophaeata was introduced in Baltic Sea as well
as in Guadalquivir River in Spain by ballast water transport [
7, 8
]. Multiple introductions of
the same species have also been reported. Melanoides tuberculata, native from eastern Africa
and the Middle East was deliberately introduced in 1980 for snail control in the Caribbean [
9
],
and also inadvertently from aquarium trade [
10
]. Sinanodonta woodiana whose native range is
Eastern Asia, was introduced in Tuscany (Italy) for production of artificial pearls [
11
], but in
Poland it arrived probably with fish consignments as a parasite [
12
], since it has an obligatory
parasitic stage [
13
]. Corbicula fluminea, also native to Asia, was transported inadvertently in
ballast water to Brazil [
14
], where it was also introduced from aquarium releases and attached
to feet or feathers of aquatic birds, and deliberately released as a food resource and fish bait
[
15
].
The effects caused by the molluscs cited above are enormous and mainly derived from their
high reproductive rates and their environmental tolerance. They can alter the suspended
particles and sediments, introduce new parasites and diseases and compete with native species [
16
].
The parthenogenetic M. tuberculata is a threat for the Italian endemic Melanopsis etrusca due
to its high population density [
11
]. Moreover M.tuberculata hosts a trematode parasite that
infests local fish [
17
]. C. fluminea reduces the local phytoplankton community due to high
filtration rates, altering the nutrients cycling [
18
], as it happened in the Potomac River in
Maryland, USA [
19
]. In addition, this species tolerates higher concentrations of mercury than
native molluscs, surviving better in polluted areas [
20
]. S. woodiana became the dominant
species in Poland and dispersing quickly to the rest of Europe [
21
], partly due to its high ability to
parasitize native fish species outcompeting native molluscs [
22
]. M. leucophaeata is even able
to survive in the cooling tanks of nuclear plants and spread from there [23]. Its ability to
tolerate high temperatures and chlorine concentrations makes M. leucophaeata a huge biofouling
problem once established [24, 25 (...truncated)