The Role of Aquatic Food Webs in Maintaining Ecosystem Stability and Resilience

The importance of aquatic ecosystems (both freshwater and marine ecosystems) cannot be understated, as they contribute towards biodiversity conservation and provide important ecosystem services, including nutrient recycling, carbon fixation, and fisheries. In recent years, such systems have become vulnerable to several environmental factors, namely climate change, pollution, and habitat destruction, which affect the system's capacity to function optimally and be resilient against future stresses. Food web networks, which form a network comprising the interrelationships among different organisms, form important components of maintaining ecosystem stability through energy flow, species interactions, and redundancy. This study investigates the impact of food webs on the stability and resilience of aquatic ecosystems. Experiments were carried out in the field to measure abundance and biomass of different species, using stable isotope analysis (δ¹³C and δ¹⁵N) to assign trophic levels. Food web networks were created from collected data, whereas structural properties (connectance, linkage density, mean trophic level, modularity) were determined alongside robustness, redundancy, and resilience scores. Statistical analysis, which includes principal components and redundancy analyses, was carried out to determine the effect of food web complexity on ecosystem resilience. The outcome shows that ecosystems with increased connectance and trophic complexity, especially those found in the estuarine and marine environments, display high levels of robustness and functional redundancy, thus increasing their resilience to species extinction and external disturbances. The key species that included top consumers and primary producers were found to play an important role in maintaining the stability of the networks. Seasonal variation also affected connectivity and redundancy in the ecosystem.