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. 

Newcomer, K., Tracy, B.M., Chang, A.L. and Ruiz, G.M. 2019. Evaluating Performance of Photographs for Marine Citizen Science Applications. Front. Mar. Sci., (Online 18 June 2019)

Gestoso, I., Cacabelos, E., Ramalhosa, P. and Cannhing-Clode, J. 2019. Plasticrusts: A new potential threat in the Anthropocene's rocky shores. Science of the Total Environment 687:413–415 (Online June 8, 2019)

Tagliapietra, D., Sigovini, M., Keppel, E., Guarneri, I., Palanti, S., Veronese, N., Abbate., A. 2019. Bioerosion effects of sea-level rise on the Doge’s Palace water doors in Venice (Italy). Facies:65: 34.  (online June 8, 2019)

Ulrich, B., Archambault, p., […], Canning Clode, J [...], Alison C. 2019. Predator traits determine food-web architecture across ecosystems. Nature Ecology & Evolution. (Online May 20, 2019)

 Cheng, B.S., Altieri, A.H., Torchin, M.E., Ruiz, G.M., 2019.  Can marine reserves restore lost ecosystem functioning? A global synthesis. Ecology 100(4) (online April 1, 2019)


June 18, 2019

Newcomer, K., Tracy, B.M., Chang, A.L. and Ruiz, G.M. 2019. Evaluating Performance of Photographs for Marine Citizen Science Applications. Front. Mar. Sci., 

Long-term measurements are imperative to detect, understand, and predict changes in coastal biological communities, but can be both costly and difficult to implement. Here, we compare measurement methods used to document community structure and assess changes in marine systems, and explore potential applications in citizen science. The use of photographs for species identifications and monitoring has become a popular and useful data collection tool, but its use requires evaluation of its effectiveness in comparison to data collected from live examinations. We used settlement panels in San Francisco Bay, a well-studied and vital coastal ecosystem, to compare standardized measures of the invertebrate fouling community through examination of live organisms in the field and via photographs. Overall, our study found that live measurements were more accurate and better represented these marine communities, having higher richness, and diversity measurements than photographic measurements. However, photographic analyses accurately captured the relative abundances of some species and functional groups. We suggest that highly recognizable target taxa or broad scale comparisons of functional group composition are easily tracked through photographs and offer the best potential for research conducted by citizen scientists.

June 8, 2019

Gestoso, I., Cacabelos, E., Ramalhosa, P. and Cannhing-Clode, J. 2019. Plasticrusts: A new potential threat in the Anthropocene's rocky shores. Science of the Total Environment 687:413–415 (Online June 8, 2019)

Plastic debris is one of the most extensive pollution problems our planet is facing today and a particular concern for marine environment conservation. The dimension of the problem is so large that it is possible our current era will generate an anthropogenic marker horizon of plastic in earth's sedimentary record. Here we present a new type of plastic pollution, the ‘plasticrusts’, plastic debris encrusting the rocky surface, recently discovered in the intertidal rocky shores of a volcanic Atlantic island. The potential impact that these new ‘plasticrusts’ may have needs to be further explored, as e.g. potential ingestion by intertidal organisms could suppose a new pathway for entrance of plastics into marine food webs. Consequently, its inclusion as a potential new marine debris category in management and monitoring actions should be pondered.

Tagliapietra, D., Sigovini, M., Keppel, E., Guarneri, I., Palanti, S., Veronese, N., Abbate., A. 2019. Bioerosion effects of sea-level rise on the Doge’s Palace water doors in Venice (Italy). Facies:65: 34.  (online June 8, 2019)

The Doge’s Palace of Venice (Italy) has on its canal-side large doorways closed by old wooden doors. Originally, the thresholds were built above high-water level to avoid direct contact with the water and the resulting damage caused by physical and biological agents. As a result of sea-level rise and land subsidence during the last centuries, the doors are now exposed to tides and to attack by marine wood-boring invertebrates such as shipworms and gribbles. As a consequence, the bottom rails of the doors were recently in need of substantial restoration, which took into consideration new materials and techniques. In this framework, an in situ experiment was undertaken to test the resistance of some selected wood species to woodboring organisms. A quick assessment protocol, based on the EN 275 standard, was set up to quantify bioerosion according to wood species and elevation above sea level. Both European and tropical wood species were tested. The former include Scots Pine, as a reference, and Larch, Cypress and Oak as traditional carpentry materials. The latter include Azobe, Okan, and Bilinga. All the European species showed high susceptibility to woodborer attack, whereas no damage was recorded on the tropical woods. The collected shipworms belonged mostly to Lyrodus pedicellatus and Teredo bartschi with some individuals of Teredo navalis. The only species of gribble found was Limnoria tripunctata. New technical solutions were adopted in the restoration aiming to provide a long service life for the replacements and simplifying the maintenance procedures. Experience, results and solutions are presented.

May 20, 2019

Ulrich, B., Archambault, p., […],  Canning Clode, J [...],  Alison C. 2019. Predator traits determine food-web architecture across ecosystems. Nature Ecology & Evolution. 

Predator–prey interactions in natural ecosystems generate complex food webs that have a simple universal body-size architecture where predators are systematically larger than their prey. Food-web theory shows that the highest predator–prey body-mass ratios found in natural food webs may be especially important because they create weak interactions with slow dynamics that stabilize communities against perturbations and maintain ecosystem functioning. Identifying these vital interactions in real communities typically requires arduous identification of interactions in complex food webs. Here, we overcome this obstacle by developing predator-trait models to predict average body-mass ratios based on a database comprising 290 food webs from freshwater, marine and terrestrial ecosystems across all continents. We analysed how species traits constrain body-size architecture by changing the slope of the predator–prey body-mass scaling. Across ecosystems, we found high body-mass ratios for predator groups with specific trait combinations including (1) small vertebrates and (2) large swimming or flying predators. Including the metabolic and movement types of predators increased the accuracy of predicting which species are engaged in high body-mass ratio interactions. We demonstrate that species traits explain striking patterns in the body-size architecture of natural food webs that underpin the stability and functioning of ecosystems, paving the way for community-level management of the most complex natural ecosystems.

April 1, 2019

Cheng, B.S., Altieri, A.H., Torchin, M.E., Ruiz, G.M., 2019.  Can marine reserves restore lost ecosystem functioning? A global synthesis. Ecology 100(4)

Marine protected areas (MPAs) have grown exponentially, emerging as a widespread tool to conserve biodiversity and enhance fisheries production. Although numerous empirical studies and global syntheses have evaluated the effects of MPAs on community structure (e.g., biodiversity), no broad assessment concerning their capacity to influence ecological processes (e.g., species interactions) exists. Here, we present meta‐analyses that compare rates of predation and herbivory on a combined 32 species across 30 MPAs spanning 85° of latitude. Our analyses synthesize the fate of 15,225 field experiment assays, and demonstrate that MPAs greatly increased predation intensity on animals but not herbivory on macroalgae or seagrass. Predation risk, quantified as the odds of prey being eaten, was largely determined by predator abundance and biomass within reserves. At MPAs with the greatest predator accumulation, the odds of predation increased to nearly 49:1, as opposed to 1:1 at MPAs where predators actually declined. Surprisingly, we also found evidence that predation risk declined with increased sea‐surface temperature. Greater predation risk within MPAs was consistent with predator and prey population abundance estimates, where predators increased 4.4‐fold within MPAs, whereas prey decreased 2.2‐fold. For herbivory, the lack of change may have been driven by functional redundancy and the inability of reserves to increase herbivore abundance relative to fished zones in our sample. Overall, this work highlights the capacity of MPAs to restore a critical ecosystem function such as predation, which mediates energy flows and community assembly within natural systems. However, our review of the literature also uncovers relatively few studies that have quantified the effects of MPAs on ecosystem function, highlighting a key gap in our understanding of how protected areas may alter ecological processes and deliver ecosystem services. From a historical perspective, these findings suggest that modern levels of predation in the coastal oceans may currently only be a fraction of the baseline prior to human exploitation.


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

Laravel tunicates

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).