I am a quantitative and computational marine ecologist specialized in research synthesis. My scientific work is on marine conservation, fishery sciences, population dynamics, and quantitative ecology with a special interest in sharks and rays. I combine ecology, statistical modeling, and computer science to approach questions on animal abundance and distribution, species interactions, large marine predators, top-down control, structure and functioning of large marine ecosystems.
Master of Science, Polytechnic University of Marche, Marine Biology (2003)
Doctor of Philosophy, Dalhousie University (2011)
Barbara Block, Postdoctoral Faculty Sponsor
Trends in the exploitation of South Atlantic shark populations
View details for DOI 10.1111/cobi.12663
Large marine protected areas (LMPAs) in the Mediterranean Sea: The opportunity of the Adriatic Sea
View details for DOI 10.1016/j.marpol.2016.03.010
- Reconciling predator conservation with public safety FRONTIERS IN ECOLOGY AND THE ENVIRONMENT 2015; 13 (8): 412-417
- Reconciling predator conservation with public safety FRONTIERS IN ECOLOGY AND THE ENVIRONMENT 2015
Falling through the cracks: the fading history of a large iconic predator
FISH AND FISHERIES
View details for DOI 10.1111/faf.12108
- Sharks and other elasmobranchs World Ocean Assessment United Nations. 2015
- Ocean Health Handbook of Ocean Resources and Management Routledge. 2015
Predator decline leads to decreased stability in a coastal fish community
2014; 17 (12): 1518-1525
Fisheries exploitation has caused widespread declines in marine predators. Theory predicts that predator depletion will destabilise lower trophic levels, making natural communities more vulnerable to environmental perturbations. However, empirical evidence has been limited. Using a community matrix model, we empirically assessed trends in the stability of a multispecies coastal fish community over the course of predator depletion. Three indices of community stability (resistance, resilience and reactivity) revealed significantly decreasing stability concurrent with declining predator abundance. The trophically downgraded community exhibited weaker top-down control, leading to predator-release processes in lower trophic levels and increased susceptibility to perturbation. At the community level, our results suggest that high predator abundance acts as a stabilising force to the naturally stochastic and highly autocorrelated dynamics in low trophic species. These findings have important implications for the conservation and management of predators in marine ecosystems and provide empirical support for the theory of predatory control.
View details for DOI 10.1111/ele.12354
View details for Web of Science ID 000345216200004
View details for PubMedID 25224645
- Using Disparate Datasets to Reconstruct Historical Baselines of Animal Populations Marine Historical Ecology in Conservation University of California Press. 2014
- Geographical distribution and status. 7.2.1 Mediterranean Sea Sawfish: A Global Strategy for Conservation IUCN. 2014
Cumulative Human Impacts on Mediterranean and Black Sea Marine Ecosystems: Assessing Current Pressures and Opportunities
2013; 8 (12)
Management of marine ecosystems requires spatial information on current impacts. In several marine regions, including the Mediterranean and Black Sea, legal mandates and agreements to implement ecosystem-based management and spatial plans provide new opportunities to balance uses and protection of marine ecosystems. Analyses of the intensity and distribution of cumulative impacts of human activities directly connected to the ecological goals of these policy efforts are critically needed. Quantification and mapping of the cumulative impact of 22 drivers to 17 marine ecosystems reveals that 20% of the entire basin and 60-99% of the territorial waters of EU member states are heavily impacted, with high human impact occurring in all ecoregions and territorial waters. Less than 1% of these regions are relatively unaffected. This high impact results from multiple drivers, rather than one individual use or stressor, with climatic drivers (increasing temperature and UV, and acidification), demersal fishing, ship traffic, and, in coastal areas, pollution from land accounting for a majority of cumulative impacts. These results show that coordinated management of key areas and activities could significantly improve the condition of these marine ecosystems.
View details for DOI 10.1371/journal.pone.0079889
View details for Web of Science ID 000327949300012
View details for PubMedID 24324585
- Long-term change in a meso-predator community in response to prolonged and heterogeneous human impact SCIENTIFIC REPORTS 2013; 3
Long-term change in a meso-predator community in response to prolonged and heterogeneous human impact.
2013; 3: 1057-?
Sharks and rays' abundance can decline considerably with fishing. Community changes, however, are more complex because of species interactions, and variable vulnerability and exposure to fishing. We evaluated long-term changes in the elasmobranch community of the Adriatic Sea, a heavily exploited Mediterranean basin where top-predators have been strongly depleted historically, and fishing developed unevenly between the western and eastern side. Combining and standardizing catch data from five trawl surveys from 1948-2005, we estimated abundance trends and explained community changes using life histories, fish-market and effort data, and historical information. We identified a highly depleted elasmobranch community. Since 1948, catch rates have declined by >94% and 11 species ceased to be detected. The exploitation history and spatial gradients in fishing pressure explained most patterns in abundance and diversity, including the absence of strong compensatory increases. Ecological corridors and large-scale protected areas emerged as potential management options for elasmobranch conservation.
View details for DOI 10.1038/srep01057
View details for PubMedID 23308344
- From archives to conservation: why historical data are needed to set baselines for marine animals and ecosystems CONSERVATION LETTERS 2012; 5 (5): 349-359
The Structure of Mediterranean Rocky Reef Ecosystems across Environmental and Human Gradients, and Conservation Implications
2012; 7 (2)
Historical exploitation of the Mediterranean Sea and the absence of rigorous baselines makes it difficult to evaluate the current health of the marine ecosystems and the efficacy of conservation actions at the ecosystem level. Here we establish the first current baseline and gradient of ecosystem structure of nearshore rocky reefs at the Mediterranean scale. We conducted underwater surveys in 14 marine protected areas and 18 open access sites across the Mediterranean, and across a 31-fold range of fish biomass (from 3.8 to 118 g m(-2)). Our data showed remarkable variation in the structure of rocky reef ecosystems. Multivariate analysis showed three alternative community states: (1) large fish biomass and reefs dominated by non-canopy algae, (2) lower fish biomass but abundant native algal canopies and suspension feeders, and (3) low fish biomass and extensive barrens, with areas covered by turf algae. Our results suggest that the healthiest shallow rocky reef ecosystems in the Mediterranean have both large fish and algal biomass. Protection level and primary production were the only variables significantly correlated to community biomass structure. Fish biomass was significantly larger in well-enforced no-take marine reserves, but there were no significant differences between multi-use marine protected areas (which allow some fishing) and open access areas at the regional scale. The gradients reported here represent a trajectory of degradation that can be used to assess the health of any similar habitat in the Mediterranean, and to evaluate the efficacy of marine protected areas.
View details for DOI 10.1371/journal.pone.0032742
View details for Web of Science ID 000303003500099
View details for PubMedID 22393445
- Correlates of Vertebrate Extinction Risk in Canada BIOSCIENCE 2011; 61 (7): 538-549
Patterns and ecosystem consequences of shark declines in the ocean
2010; 13 (8): 1055-1071
Whereas many land predators disappeared before their ecological roles were studied, the decline of marine apex predators is still unfolding. Large sharks in particular have experienced rapid declines over the last decades. In this study, we review the documented changes in exploited elasmobranch communities in coastal, demersal, and pelagic habitats, and synthesize the effects of sharks on their prey and wider communities. We show that the high natural diversity and abundance of sharks is vulnerable to even light fishing pressure. The decline of large predatory sharks reduces natural mortality in a range of prey, contributing to changes in abundance, distribution, and behaviour of small elasmobranchs, marine mammals, and sea turtles that have few other predators. Through direct predation and behavioural modifications, top-down effects of sharks have led to cascading changes in some coastal ecosystems. In demersal and pelagic communities, there is increasing evidence of mesopredator release, but cascading effects are more hypothetical. Here, fishing pressure on mesopredators may mask or even reverse some ecosystem effects. In conclusion, large sharks can exert strong top-down forces with the potential to shape marine communities over large spatial and temporal scales. Yet more empirical evidence is needed to test the generality of these effects throughout the ocean.
View details for DOI 10.1111/j.1461-0248.2010.01489.x
View details for Web of Science ID 000279934400012
View details for PubMedID 20528897
- Assessment of the Mediterranean swordfish based on the Italian harpoon fishery data. ICES CM 2009; K:16: 1-14
Loss of large predatory sharks from the Mediterranean Sea
2008; 22 (4): 952-964
Evidence for severe declines in large predatory fishes is increasing around the world. Because of its long history of intense fishing, the Mediterranean Sea offers a unique perspective on fish population declines over historical timescales. We used a diverse set of records dating back to the early 19th and mid 20th century to reconstruct long-term population trends of large predatory sharks in the northwestern Mediterranean Sea. We compiled 9 time series of abundance indices from commercial and recreational fishery landings, scientific surveys, and sighting records. Generalized linear models were used to extract instantaneous rates of change from each data set, and a meta-analysis was conducted to compare population trends. Only 5 of the 20 species we considered had sufficient records for analysis. Hammerhead (Sphyrna spp.), blue (Prionace glauca), mackerel (Isurus oxyrinchus and Lamna nasus), and thresher sharks (Alopias vulpinus) declined between 96 and 99.99% relative to their former abundance. According to World Conservation Union (IUCN) criteria, these species would be considered critically endangered. So far, the lack of quantitative population assessments has impeded shark conservation in the Mediterranean Sea. Our study fills this critical information gap, suggesting that current levels of exploitation put large sharks at risk of extinction in the Mediterranean Sea. Possible ecosystem effects of these losses involve a disruption of top-down control and a release of midlevel consumers.
View details for DOI 10.1111/j.1523-1739.2008.00938.x
View details for Web of Science ID 000258216600021
View details for PubMedID 18544092
- By-Catch of sharks in the Mediterranean Sea: available mitigation tools Proceedings of the Workshop on the Mediterranean Cartilaginous Fish with emphasis on Southern and Eastern Mediterranean Turkish marine research foundation; UNEP-MAP; RAC/SPA. 2006
- Long Term Dynamics of the Chondrichthyan Fish Community in the Upper Tyrrhenian Sea ICES CM 2005; N:25: 1-25