Published in June 2016
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Viewpoint
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Frances E. Lucy, Helen Roy, Annie Simpson, James T. Carlton, John Mark Hanson, Kit Magellan,
Marnie L. Campbell, Mark J. Costello, Shyama Pagad, Chad L. Hewitt, Justin McDonald, Phillip Cassey, Sidinei M. Thomaz, Stelios Katsanevakis,
Argyro Zenetos, Elena Tricarico, Angela Boggero, Quentin J. Groom, Tim Adriaens, Sonia Vanderhoeven, Mark Torchin, Ruth Hufbauer, Pam Fuller,
Mary R. Carman, David Bruce Conn, Jean R.S. Vitule, João Canning-Clode, Bella S. Galil, Henn Ojaveer, Sarah A. Bailey, Thomas W. Therriault,
Renata Claudi, Anna Gazda, Jaimie T.A. Dick, Joe Caffrey, Arne Witt, Marc Kenis, Maiju Lehtiniemi, Harry Helmisaari and Vadim E. Panov
INVASIVESNET towards an International Association for Open Knowledge on Invasive Alien Species (pp 131-139) |
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In a world where invasive alien species (IAS) are recognised as one of the major threats to biodiversity, leading scientists from five continents
have come together to propose the concept of developing an international association for open knowledge and open data on IAS—termed “INVASIVESNET”.
This new association will facilitate greater understanding and improved management of invasive alien species (IAS) and biological invasions globally,
by developing a sustainable network of networks for effective knowledge exchange. In addition to their inclusion in the CBD Strategic Plan for Biodiversity,
the increasing ecological, social, cultural and economic impacts associated with IAS have driven the development of multiple legal instruments and policies.
This increases the need for greater co-ordination, co-operation, and information exchange among scientists, management, the community of practice and the public.
INVASIVESNET will be formed by linking new and existing networks of interested stakeholders including international and national expert working groups
and initiatives, individual scientists, database managers, thematic open access journals, environmental agencies, practitioners, managers, industry,
non-government organisations, citizens and educational bodies. The association will develop technical tools and cyberinfrastructure for the collection,
management and dissemination of data and information on IAS; create an effective communication platform for global stakeholders; and promote coordination
and collaboration through international meetings, workshops, education, training and outreach.
To date, the sustainability of many strategic national and international
initiatives on IAS have unfortunately been hampered by time-limited grants or
funding cycles. Recognising that IAS initiatives need to be globally coordinated
and on-going, we aim to develop a sustainable knowledge sharing association to
connect the outputs of IAS research and to inform the consequential management
and societal challenges arising from IAS introductions. INVASIVESNET will
provide a dynamic and enduring network of networks to ensure the continuity of
connections among the IAS community of practice, science and management.
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Research articles
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Deborah J. Shafer, Todd M. Swannack, Christina Saltus, James E. Kaldy and Austin Davis
Development and validation of a habitat suitability model for the non-indigenous seagrass Zostera japonica in North America (pp 141-155) |
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We developed a spatially-explicit, habitat suitability model that can be used to identify and predict areas at higher risk for non-native dwarf eelgrass
(Zostera japonica) invasion. The niche-based model uses simple readily available environmental parameters (depth, near shore slope, and salinity)
to quantitatively describe habitat suitable for Z. japonica invasion based on ecology and physiology from the primary literature. Habitat suitability
is defined with values ranging from zero to one, where one denotes areas most conducive to Z. japonica and zero denotes areas not likely to support
Z. japonica growth. Functional forms and equations for the ZJHSM were developed a priori, and the model was validated by comparison with multiple
years of independent field-collected spatial Z. japonica maps from Yaquina Bay, Oregon, USA, an area that has well documented Z. japonica
expansion over the last two decades. Sensitivity analysis performed to evaluate the contribution of each parameter to the model prediction revealed that
depth was the most important factor. The highest suitability values for Z. japonica occurred in the mid to upper portions of the intertidal zone,
with larger expanses occurring in the lower estuary. While the upper estuary did contain suitable habitat, most areas were not as large as in the lower
estuary, due to inappropriate depth, a steeply sloping intertidal zone, and lower salinity. The lowest suitability values occurred below the lower
intertidal zone, within the Yaquina River channel. Shallow sloping intertidal soft-bottom sediments appear to provide optimum habitat for this species.
This model would allow resource managers to identify those areas at risk for future invasion, and develop proactive plans for limiting the opportunities
for further introduction and spread in areas where it does not currently occur.
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J. Ben Lowen, Don Deibel, Cynthia H. McKenzie, Cyr Couturier and Claudio DiBacco
Tolerance of early life-stages in Ciona intestinalis to bubble streams and suspended particles (pp 157-165) |
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There is an urgent need to develop and test potential eradication agents to prevent biofouling by ascidian tunicates in sheltered harbor’s before
they can spread to, and subsequently, disrupt benthic ecosystems and aquaculture ventures. We test the effects of bubble streams and suspended particles
on two key stages in the early life cycle of Ciona intestinalis (Linnaeus, 1767); (i) Larval settlement 3 d after introducing free swimming larvae,
and (ii) juvenile survival following exposure of ~ 21 d old juvenile recruits to the tested treatments for the first time. Larval settlement was effectively
prevented after exposure to bubble streams at > 10 l min-1 or ≥ 25 Nephelometric Turbidity Units (NTU) of suspended particles. Suspended particles settling
as a layer ≥ 0.3 mm thick onto the test substrate also reduced larval settlement by over 90%. None of the treatments were effective at eradicating juvenile
C. intestinalis which proved more resistant to the tested treatments. Body size in juvenile recruits was also not significantly different across
bubble stream rates. Juvenile recruits exposed to suspended particles were, however, significantly smaller than in the control treatment. In conclusion,
as C. intestinalis settled, and grew, it became progressively more resilient to the tested treatments. Thus, continuous treatment is required during
the spawning season to target larval settlement and prevent fouling by Ciona intestinalis.
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John D.P. Davidson, Thomas Landry, Gerald R. Johnson, Aaron Ramsay and Pedro A. Quijón
A field trial to determine the optimal treatment regime for Ciona intestinalis on mussel socks (pp 167-179) |
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The invasive tunicate species Ciona intestinalis (Linnaeus, 1767) has had an economic impact on the aquaculture of the blue mussel
Mytilus edulis (Linnaeus, 1758) in Prince Edward Island (PEI). This tunicate fouls mussel socks suspended on long lines in the water
and reduces both weight and numbers of mussels, decreasing overall productivity. This study determined the relative effects of high pressure
water treatment schedules over a four month period on two sites in the Murray and Brudenell Rivers on PEI. Results indicated that initiating
treatment early (July) in the season and treating another two or three times during the season had the greatest effect on reducing tunicate
numbers and size and enabling greater mussel productivity. While the most effective treatment may ultimately be site-specific, the two sites
in this study support the notion that beginning treatment when tunicates are small is one of the most significant parts of the treatment plan.
Two or more treatments (approximately monthly) are then needed to effectively control C. intestinalis, and allow mussels to reach their
full growth potential.
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Louis F. Ferguson, Thomas Landry, Thomas W. Therriault and Jeff Davidson
Effectiveness of a neutral red viability protocol developed for two colonial tunicate species (pp 181-187) |
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In order to evaluate the potential risk posed by transporting invasive tunicates away from infested sites it is important to be able to measure
the viability of these organisms. A Neutral Red (NR) viability assay was developed using a colonial invasive tunicate, Botrylloides violaceus
(Oka, 1927) that could be applied to other species. Unlike some colonial tunicates B. violaceus’ mortality can be determined under light microscopy
by observing changes in the physiological parameters of filtration and reaction to tactile stimulus making them a good study organism. A total of 32
B. violaceus segments (3 cm²) were allocated to treatment and control groups. The treatment group was subjected to acetic acid which resulted
in 100 % mortality. Viability was then assessed by comparing treatment and control group responses to NR uptake. There was no mortality in the control
that demonstrated a response to tactile stimulus and a noticeable amount of stain uptake inside zooids. In contrast, the treatment groups did not respond
to tactile stimulus and no stain was taken in by the zooids. In this study the viability of Didemnum vexillum (Kott, 2002) was assessed under
controlled experimental conditions by simulating the air exposure encountered during the normal transportation and processing of tunicate fouled Pacific
oysters, Crassostrea gigas (Thunberg, 1793). Clusters containing C. gigas and D. vexillum were collected from an aquaculture lease,
in Lemmens Inlet, BC, for an air exposure trial comprised of 9 equally divided treatments (0, 0.5, 1.5, 3, 6, 12, 24, 48 and 72 hours). Three segments
of D. vexillum on each cluster were removed and evaluated with the NR protocol developed for B. violaceus. Preserved tissues were analyzed
and no sign of stain was noticeable, even with the control segments. The NR protocol developed worked efficiently with B. violaceus, but appeared
to fail with D. vexillum. The findings are consistent with D. vexillum demonstrating a high tolerance in situations they are not accustomed
to reflecting their ability to enter a dormant state during adverse environmental conditions (hence lack of response to clinical or NR markers via lack
of filtering). Further studies are required to determine the viability of D. vexillum and potential risk movements pose.
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P. Joana Dias, Tiffany Simpson, Yvette Hitchen, Sherralee Lukehurst, Michael Snow and W. Jason Kennington
Isolation and characterization of 17 polymorphic microsatellite loci for the widespread ascidian Didemnum perlucidum (Tunicata, Ascidiacea) (pp 189-191) |
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The colonial tunicate Didemnum perlucidum has been identified from numerous tropical and temperate locations worldwide, but its native
and introduced ranges remain largely unknown. In Australia, D. perlucidum is listed as a target species under the introduced marine pest
national monitoring network. In order to investigate the introduced status and potential routes of introduction and dispersal of D. perlucidum,
we developed 17 new polymorphic microsatellite markers using 454 shotgun sequencing. Two to six alleles per locus were detected. No evidence
of linkage disequilibrium between pairs of loci was identified and 12 of the 17 loci were in Hardy-Weinberg equilibrium.
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Robert N. Reed, Matthew W. Hopken, David A. Steen, Bryan G. Falk and Antoinette J. Piaggio
Integrating early detection with DNA barcoding: species identification of a non-native monitor lizard (Squamata: Varanidae) carcass in Mississippi, U.S.A. (pp 193-197) |
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Early detection of invasive species is critical to increasing the probability of successful management. At the primary stage of an invasion, invasive
species are easier to control as the population is likely represented by just a few individuals. Detection of these first few individuals
can be challenging, particularly if they are cryptic or otherwise characterized by low detectability. The engagement of members of the public may be
critical to early detection as there are far more citizens on the landscape than trained biologists. However, it can be difficult to assess the credibility
of public reporting, especially when a diagnostic digital image or a physical specimen in good condition are lacking. DNA barcoding can be used
for verification when morphological identification of a specimen is not possible or uncertain (i.e., degraded or partial specimen). DNA barcoding relies
on obtaining a DNA sequence from a relatively small fragment of mitochondrial DNA and comparing it to a database of sequences containing a variety
of expertly identified species. Herein we report the successful identification of a degraded specimen of a non-native, potentially invasive reptile species
(Varanus niloticus) via DNA barcoding, after discovery and reporting by a member of the public.
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Danielle E. Verna, Bradley P. Harris, Kimberly K. Holzer and Mark S. Minton
Ballast-borne marine invasive species: exploring the risk to coastal Alaska, USA (pp 199-211) |
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The relatively uninvaded coastline of Alaska currently faces a heightened risk of novel biological introductions as a result of increasing regional
vessel traffic, emerging Arctic trade routes, and proposed coastal and nearshore development. Alaska currently receives the majority of its ballast
water discharge in the port of Valdez (86%), largely from crude oil tankers engaged in coastwise trade. These crude oil tankers were exempted from
managing and reporting ballast water prior to the United States Environmental Protection Agency’s 2008 Vessel General Permit (VGP). Here we present
a comprehensive statewide risk assessment of ballast-borne marine invasive species throughout coastal Alaska, and the first study to characterize
the risk from the ballast water vector following inclusion of ballast water reporting by the VGP. We examined ballast water discharge volume,
environmental similarity between source and discharge regions, ballast water age, and marine invasive species richness in source regions annually
from 2009 – 2012 for the top 15 ports/discharge locations in Alaska. The majority (80%) of the more than 54 million metric tons of reported ballast
water discharged during this time period was sourced from the west coast of North America, including highly invaded port systems such as San Francisco Bay,
California and Puget Sound, Washington. Overall about 38% of the ballast water discharged to our focus locations was managed using ballast water exchange.
We conclude that the risk of invasion is highest for the ports of Valdez and Drift River Terminal and lowest for the ports of Klawock, Skagway, and Tolstoi Bay.
This analysis and risk matrix can inform further fine-scale assessments of ballast water management activity and identify areas of Alaska most likely
to benefit from focused management efforts.
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