Metaweb approach to unravel food web structures: Exploring environmental changes and biotic interactions in Korean stream ecosystems

• Freshwater food webs were analyzed using network theory and metaweb analysis. • Web patterns were linked to water quality, land use, temperature, and stream order. • Food web structures responded to environmental variables beyond general trends. • Habitat heterogeneity influences food web responses. • The food web approach can complement traditional community-based analyses. Understanding food webs is crucial for grasping ecosystem functions and energy flows. However, the inherent complexity and variability of food web structures pose significant challenges to community ecology. The concept of a metaweb is key to overcoming these challenges. Metawebs enable the construction of food webs using biomonitoring data, and provide a comprehensive analysis of ecosystem interactions. Using network theory and food web metrics, we (1) applied metaweb approaches to construct and compare local food webs across multiple study sites, offering a holistic perspective on regional ecosystem dynamics; (2) examined the impacts of environmental changes on food web structures to identify patterns indicative of ecosystem status; and (3) evaluated the influence of habitat heterogeneity on food web configuration. Local food webs were constructed using the KF-metaweb and biomonitoring data from Korean streams, and food web structure metrics were subsequently calculated. Hierarchical cluster analysis of 255 local food webs, based on similarities in food web metrics, revealed five distinct clusters. Non-metric multidimensional scaling illustrated the relationships among food web metrics, environmental variables, and biological indices. The structural patterns of local food webs are associated with water quality, land use type, temperature, and stream magnitude. The responses of food web structures to environmental factors varied both in general trends and across clusters, highlighting the role of habitat heterogeneity in shaping food web responses. Certain food web metrics exhibit limited explanatory power regarding ecosystem status. This study provides a basis for future research by enabling cross-site comparisons using a metaweb framework, thereby advancing our understanding of ecological interactions and ecosystem dynamics.