Ecological Network Analysis of Marine Ecosystems

Ecological network analysis (ENA) applies systems theory to marine environments by mapping the interactions among species, functional groups and abiotic compartments to quantify energy and matter flows. By representing food webs as networks of nodes and links, researchers can compute indicators such as ascendency, redundancy, connectance and cycling indices to characterise ecosystem structure, function and resilience. ENA offers a unifying framework to compare diverse habitats—from coastal estuaries to open-ocean realms—and to assess responses to stressors including fishing, pollution and climate change. Coupled with dynamic tools such as Ecopath with Ecosim, network methods support scenario testing for fisheries management, conservation planning and the evaluation of human interventions. Across biogeographical regions, ENA reveals common organisational patterns and highlights keystone taxa, enabling ecosystem-based management that recognises non-linear feedbacks and emergent properties critical to sustaining marine resources.

Research from Nature Portfolio

Recent methodological work has advanced the comparison between conventional flow-based ENA and novel information-based approaches. By applying both techniques to long-term socio-ecological data, researchers demonstrated that information-based networks capture adaptive cycle dynamics more closely than flow-analysis alone. This comparison revealed distinct interpretations of resilience and system organisation, underscoring that when material-flow data are sparse or incomplete, information-based metrics can offer valuable proxies. Moreover, integrating both perspectives within a single framework yields richer insights into the stability and developmental trajectories of complex systems, a finding readily transferable to marine food webs where data limitations often challenge traditional modelling.

Ecological Network Analysis of Marine Ecosystems publication trend

The graph below shows the total number of articles in ecological network analysis of marine ecosystems across all publications each year (not limited to Nature Index journals).

Technical terms

Ecological network analysis: Framework for mapping and quantifying interactions and flows among species and compartments within an ecosystem.

Ascendency: Composite measure of the magnitude and organisation of energy or matter flows, indicating system performance and efficiency.

Information-based network analysis (QtAC): Approach modelling interactions as transfers of information, enabling network assessment where material-flow data are limited.

Flow-based network analysis: Conventional ENA method quantifying physical transfers of energy or matter through food-web links.

Finn’s Cycling Index: Proportion of total system throughput that is recycled within the network, reflecting internal cycling strength.

Connectance: Ratio of observed links to all possible links in a network, used as an indicator of complexity and interaction density.

References

1. Detection of fishing pressure using ecological network indicators derived from ecosystem models. Ecological Indicators (2023).
2. Ecological networks reveal important taxa for ecosystem function in two subtropical South African estuaries. Environmental Development (2024).
3. Measuring system resilience through a comparison of information- and flow-based network analyses. Scientific Reports (2024).
4. Best practice in Ecopath with Ecosim food-web models for ecosystem-based management. Ecological Modelling (2016).
5. Global Patterns in Ecological Indicators of Marine Food Webs: A Modelling Approach. PLOS ONE (2014).