Marine Invasions Research

Principal Investigator

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Biological invasions - the establishment of species beyond their historical range - are a major force of ecological and evolutionary change. Our lab aims to understand the patterns, processes, and consequences of invasions in marine ecosystems on local to global scales.  We have laboratories and staff on both coasts of North America, on Chesapeake Bay and San Francisco Bay (Tiburon Lab).  These bays are focal points for our long-term, intensive research, which spans Pacific and Atlantic shorelines of the Americas --- from polar to tropical latitudes. 

Most marine invasions result from human-mediated species transfers, which are often associated with commercial and recreational vessels. A major component of our research examines shipping, transportation, and trade dynamics for the United States with the National Ballast Information Clearinghouse (NBIC), a joint program with the U.S. Coast Guard that is based at SERC.  NBIC tracks the status and trends of ballast water delivery and management for the Nation.

Our research encompasses a wide range of projects, exploring the ecology and management of coastal marine ecosystems.  We focus primarily on invasion dynamics but also examine species interactions of both native and non-native species. Overall, we seek to: (1) characterize patterns of marine invasion across space, time, and taxonomic groups; (2) develop a mechanistic understanding of the processes that drive observed patterns; (3) advance predictive capability about the establishment, spread, and impacts of non-native species in marine ecosystems; (4) evaluate the efficacy of management strategies to limit the establishment and impact of invaders; and (5) understand the roles of species interactions, including predator-prey and host-parasite relationships, in marine communities. 

Further details on the various dimensions of our work are available below. 

Copp, G.H., ... Canning-Clode, J. ... Mendoza, R. 2020. Speaking their language – Development of a multilingual decision-support tool for communicating invasive species risks to decision makers and stakeholders. Environmental Modeling and Software 135  (Online October 13, 2020)

Miller, A.W., Reynolds, A., Minton, M.S., and Smith, R. 2020. Evidence for stage-based larval vulnerability and resilience to acidification in Crassostrea virginica. Journal of Molluscan Studies, eyaa022, https://doi.org/10.1093/mollus/eyaa022 (Online September 8, 2020)

Wasson, K., Gossard, D.J., Gardner, L., Hain, P.R., Zabin, C.J., Forf, S., Ridlon, A.D., Bible, J.M, Deck, A.K., and Hughes, B.B. 2020. A scientific framework for conservation aquaculture: A case study of oyster restoration in central California. Biological Conservation 250. (online September 2, 2020)

Radashevsky, V.I., Malyar, V.V., Pankova, V.V., Gambi, M.C., Giangrande, A., Keppel, E., Nygren, A., Al-Kandari, M., and Carlton, J.T. 2020. Disentangling invasions in the sea: Molecular analysis of a global polychaete species complex (Annelida: Spionidae: Pseudopolydora paucibranchiata). Biological Invasions https://doi.org/10.1007/s10530-020-02346-x (online August 25, 2020)

Haram, L., Sotka, E., Erik E., Byers, and J.E. 2020. Effects of novel, non-native detritus on decomposition and invertebrate community assemblage. Marine Ecology Progress Series 643: 49-61 (online June 2020)


Abstracts

October 13, 2020

Copp, G.H., ... Canning-Clode, J. ... Mendoza, R. 2020. Speaking their language – Development of a multilingual decision-support tool for communicating invasive species risks to decision makers and stakeholders. Environmental Modeling and Software 135

Environmental changes due to non-native species introductions and translocations are a global concern. Whilst understanding the causes of bioinvasions is important, there is need for decision-support tools that facilitate effective communication of the potential risks of invasive non-native species to stakeholders. Decision-support tools have been developed mostly in English language only, which increases linguistic uncertainty associated with risk assessments undertaken by assessors not of English mother tongue and who need to communicate outcomes to local stakeholders. To reduce language-based uncertainty, the Ecology-of-language’ paradigm was applied when developing the Aquatic Species Invasiveness Screening Kit GAS-ISKH, a decision-support tool that offers IC languages in which to carry out screenings and communicate outcomes to stakeholders. Topics discussed include uncertainty related to language-specific issues encountered during the AS-ISK translation and the potential benefits of a multilingual decision-support tool for reducing linguistic uncertainty and enhancing communication between scientists, environmental managers, and policy and decision makers.

September 8, 2020

Miller, A.W., Reynolds, A., Minton, M.S., and Smith, R. 2020. Evidence for stage-based larval vulnerability and resilience to acidification in Crassostrea virginica. Journal of Molluscan Studies, eyaa022, https://doi.org/10.1093/mollus/eyaa022

Using image analysis of scanning electron micrographs (SEMs), we compared differences in growth of D-stage veligers [i.e. prodissoconch I and II (PI and PII) larvae] of eastern oysters Crassostrea virginica grown in mesohaline water under high- and low-CO2 conditions. We found SEMs to reveal no evidence of dissolution or shell structure deformity for larval shells in either of the CO2 treatments but detected prominent growth lines in the PII regions of larval shells. The number of growth lines closely approximated the duration of the experiment, suggesting that growth lines are generated daily. Mean growth line interval widths were 20% greater for larval shells cultured in low- vs high-CO2 conditions. Crassostrea virginica veliger larvae were shown to tolerate high CO2 levels and aragonite saturation states (Ωarag) < 1.0, but larval growth was slowed substantially under these conditions. Differences in growth line interval width translate into substantial changes in shell area and account for previously observed differences in total shell area between the treatments, as determined by light microscopy and image analysis. Other studies have documented high mortality and malformation of D-stage larvae in bivalves when pre-veliger life stages (i.e. eggs, gastrula and trochophores) were exposed to elevated CO2. Our experiments revealed statistical differences in rates of larval survival, settlement and subsequent early-stage spat mortality for veligers reared in high- and low-CO2 conditions. Although each of these rates was measurably affected by high CO2, the magnitude of these differences was small (range across categories = 0.7–6.3%) suggesting that the impacts may not be catastrophic, as implied by several previous studies. We believe the apparent disparity among experimental results may be best explained by differential vulnerability of pre-veliger stage larvae and veligers, whereby PI and PII larvae have greater physiological capacity to withstand environmental conditions that may be thermodynamically unfavourable to calcification (i.e. Ωarag < 1.0).

September 2, 2020

Wasson, K., Gossard, D.J., Gardner, L., Hain, P.R., Zabin, C.J., Forf, S., Ridlon, A.D., Bible, J.M, Deck, A.K., and Hughes, B.B. 2020. A scientific framework for conservation aquaculture: A case study of oyster restoration in central California. Biological Conservation 250.

The emerging field of conservation aquaculture focuses on the potential for incorporating aquaculture techniques into restoration. Extensive loss of oyster reefs worldwide has led to restoration initiatives that sometimes incorporate aquaculture, but few scientific studies of this approach have been published. We developed a scientific framework to determine whether aquaculture is an appropriate conservation tool, and applied it to Olympia oysters (Ostrea lurida) in Elkhorn Slough, an estuary in central California, USA. Over 12 years of monitoring, we documented precipitous declines in density, highlighting the need for restoration. We tracked settled oysters and found that growth and survivorship is high, showing that hatchery-raised juveniles have the potential to survive to reproductive age. No natural recruitment has occurred in the estuary in seven years, suggesting that this population is recruitment limited. Thus, we determined a need for conservation aquaculture. We produced juvenile oysters from local broodstock in a hatchery and settled them on native clam shells, which we attached to stakes to form small clusters that mimic natural biogenic habitat created by this species. We deployed these near the upper limit of the intertidal range of oysters, where oyster cover dominates over non-native fouling species. The outplanted oysters grew to adult, reproductive size within months of outplanting, and survivorship was generally high, providing the first new generation of oysters in this estuary in seven years. The science-based approach we implemented and our incorporation of traditional restoration principles of natural habitat structure and dominance by native species can serve as a model for conservation aquaculture for oysters and other species.

August 25, 2020

Radashevsky, V.I., Malyar, V.V., Pankova, V.V., Gambi, M.C., Giangrande, A., Keppel, E., Nygren, A., Al-Kandari, M., and Carlton, J.T. 2020. Disentangling invasions in the sea: Molecular analysis of a global polychaete species complex (Annelida: Spionidae: Pseudopolydora paucibranchiata). Biological Invasions https://doi.org/10.1007/s10530-020-02346-x

The spionid polychaete Pseudopolydora paucibranchiata (Okuda, 1937) was originally described from Japan and has since been reported as a non-indigenous species in soft bottom communities in the Northeast Pacific, the Mediterranean Sea, around Europe, Australia, Brazil, and Florida. The diagnostic features of the adults are palps with ramified yellow chromatophores, prostomium rounded anteriorly, short occipital antenna on the caruncle, and a small disc-like pygidium. We collected Pseudopolydora with these features from locations worldwide and compared them by a molecular analysis. The Bayesian analysis of the combined dataset of three genetic markers (mitochondrial 16S rDNA, nuclear 28S rDNA and Histone 3; 811 bp in total) showed that the worms form a monophyletic group comprising four genetically different clades. We name this group the P. paucibranchiata complex and consider the clades as four pseudocryptic species. The largest examined clade comprises individuals from the Pacific Canada (British Columbia), Russia (Sea of Japan), South Korea (East Sea), Italy (Tyrrhenian and Ionian Seas), Australia (Victoria), Netherlands, and Japan, which we identify as P. paucibranchiata. The morphology, reproductive biology and ecology of P. paucibranchiata are briefly reviewed. The other three clades are referred to as Pseudopolydora vexillosa Radashevsky and Hsieh, 2000 (Vietnam, Nha Trang Bay), Pseudopolydora sp. A (Australia, Northern Territory), and Pseudopolydora sp. B (Kuwait, Arabian Gulf). We explain the occurrence of P. paucibranchiata outside of the Northwest Pacific by unintentional human-mediated transportation in ballast water and/or with commercial oyster movements in aquaculture operations, followed by successful invasions.

June 2020

Haram, L., Sotka, E., Erik E., Byers, and J.E. 2020. Effects of novel, non-native detritus on decomposition and invertebrate community assemblage. Marine Ecology Progress Series 643: 49-61 (online June 2020)

When non-native primary producers become successful, the structure and function of native detrital food webs can be fundamentally altered. Salt marsh estuaries of the southeastern USA are in part detritus-based ecosystems and rely on the annual production of detritus from a single native species, the smooth cordgrass Spartina alterniflora. Over the last several decades, the success of a novel primary producer, the red macroalga Agarophyton vermiculophyllum (formerly Gracilaria vermiculophylla), in a system historically devoid of macroalgae provides the opportunity to measure the effect of non-native basal resources on native detrital pathways. We conducted 2 in situ experiments to compare (1) decomposition rates of A. vermiculophyllum and S. alterniflora and (2) invertebrate colonization rates onto dead A. vermiculophyllum and S. alterniflora. Relative to S. alterniflora, we found that A. vermiculophyllum decomposes more rapidly, losing 80% or more of its biomass within 3 wk, while S. alterniflora lost ~50%. Experimental litterbags with decomposed A. vermiculophyllum and S. alterniflora harbored similar highly abundant invertebrate communities that differed greatly from denuded areas. Our results demonstrate that A. vermiculophyllum provides a complementary source of labile organic matter relative to S. alterniflora, boosting the amount of food and available habitat for small invertebrates of intertidal salt marshes and mudflats. Thus, non-native macrophytes may differentially affect community and ecosystem properties just as much when dead as alive, especially when they are biologically distinct from native species.

Species distributions are at the core of all ecological and evolutionary processes. Despite recognition that accelerating invasions are radically changing fundamental ecological processes, we currently lack the data for a broad scale understanding of these  patterns, emergent properties, and practical implications across both spatial and temporal scales. We are collecting quality occurrence data and using these data to understand patterns and mechanisms of invasion, and making these data publicly available for broader application by the public.

Our Projects

The impacts of introduced species pose significant challenges for conservation and restoration because they undermine a desired outcome for target species or habitats. In addition, some invasions impose significant economic costs through loss of agriculture, forestry, and fisheries products, and others, including mosquito-borne viruses and toxic algal blooms, have severe human health effects. Detailed analysis of several high-profile species invasions have highlighted the types and potential magnitude of invasion impacts that exist, however, the effect of most non-native species and the full scope of impacts from invasions remains poorly understood. To address this gap, we use a variety of approaches to characterize and test the ecological, evolutionary, and social effects of non-native species across diverse ecosystems.  This work advances understanding of how the Earth’s ecosystems function and also serve to inform resource management and conservation strategies.

Our Projects

Biological invasions provide opportunities to examine how species and ecosystems respond to new arrivals, and how species adapt to new environmental conditions. These types of “natural experiments” provide new insights into many biological processes, especially early in the colonization process, that are not possible with native communities.  We examine invasion ecology at the population, community, and ecosystem level across a diverse range of habitats and organisms, both to advance basic science and inform management and conservation strategies.

Our Projects

Managing biological invasions is a worldwide endeavor that aims to (a) prevent the human-caused spread of species, (b) control and remove unwanted species, and (c) reduce negative impacts to society and the environment. We are evaluating the efficacy and consequences of invasion management strategies and policies in coastal estuaries and marine systems.  Our work is often done in collaboration with local, state, federal and international partners and used actively to inform current management and policy decisions.

Our Projects

We study the dynamic interactions between society, trade, transport, and species in a variety of ways. These include modeling transport networks and biotic exchange, evaluating business model forecasts and their effects on trade routes and species distributions, and assessments of organism transfers across major corridors between oceans and continents.

Our Projects

Understanding how modes of human transportation affect the environment, and biological invasions in particular, is complicated and involves many components including both human and natural history. Human history because most invasions result from human-aided species transfers and invasion patterns often reflect human movements and transportation systems. Natural history because species identifications and their life history characteristics are paramount to knowing which species are non-native and how they have likely been introduced. We work to address these complexities and strive to understand the dynamics of species transport in marine systems. 

Our Projects

Balanced predation and competition are key to the health of any ecosystem. We are examining predation and competition rates in several environments including in the Rhode River near SERC where we study native species in nearshore environments and in introduced fouling communities on the Atlantic and Pacific coasts.  

Our Projects

Communities are constantly being shaped by human activities, activates that can affect hydrology, climate, chemical inputs, species richness (number of species that make up the community), as well as habitat quantity and quality. Our research focuses on how biological invasions change the marine and estuarine communities they invade and how recipient communities protect themselves from invasion. The following highlights a few of our recent projects exploring community changes resulting from nonnative species introductions.

Our Projects

Propagule Pressure in Marine Habitats

We are examining the complex, dynamic interactions between parasites and their hosts, including both the evolutionary and ecological mechanisms that influence these interactions. Our research includes a wide variety of hosts (e.g., seagrasses, bivalves, crustaceans) and parasites (e.g., protists, bacteria, crustaceans).