Predator-Prey Dynamics in Aquatic Ecosystems

Predator–prey interactions underpin the structure and function of freshwater and marine communities by regulating population sizes, driving species coexistence and shaping energy flows. Top-down control exerted by predators can cascade through trophic levels, influencing biodiversity, nutrient cycling and ecosystem resilience. Beyond direct consumption, predators also induce non-consumptive effects: changes in prey behaviour, morphology and life history traits that alter habitat use, feeding rates and growth. Habitat complexity, connectivity and environmental gradients modulate these interactions, while chemical cues released by predators or their microbiota inform prey of risk and guide oviposition, dispersal and foraging decisions. The introduction of invasive predators and anthropogenic stressors such as climate warming and habitat fragmentation further complicate dynamics by shifting species compositions and weakening natural checks on prey populations. Understanding the balance between consumptive and non-consumptive pathways, the role of keystone predators and the influence of habitat selection is essential for biodiversity conservation, fisheries management and the design of nature-based solutions to vector control and habitat restoration.

Research from Nature Portfolio

Recent studies have revealed the importance of top predators in mediating fish community assembly. A field investigation in a boreal river basin demonstrated that the presence of a generalist otter promotes species richness and evenness among stream fishes by exerting stochastic top-down control, thereby enhancing resilience and ecosystem function. In another mesocosm experiment, researchers examined semiaquatic and fully aquatic organisms with differing specialisations. They found that habitat specialists consistently avoided pools containing fish, whereas generalists exhibited variable responses depending on vegetation structure. This work highlights how life-history traits and habitat complexity interact with predator presence to determine community composition across freshwater landscapes.

Predator-Prey Dynamics in Aquatic Ecosystems publication trend

The graph below shows the total number of articles in predator-prey dynamics in aquatic ecosystems across all publications each year (not limited to Nature Index journals).

Technical terms

Consumptive effects: direct removal of prey through predation leading to mortality.

Non-consumptive effects: predator-induced changes in prey behaviour, physiology or morphology without direct consumption.

Trophic cascade: indirect interactions where predators influence lower trophic levels through their impact on intermediate consumers.

Habitat selection: the process by which organisms choose environments that maximise survival and reproductive success in the presence of predators.

Kairomones: chemical signals released by predators or their associated microbiota that are detected by prey species.

Keystone predator: a species whose impact on community structure and ecosystem function is disproportionately large relative to its abundance.

References

1. Predator-mediated diversity of stream fish assemblages in a boreal river basin, China. Scientific Reports (2023).
2. Specialization directs habitat selection responses to a top predator in semiaquatic but not aquatic taxa. Scientific Reports (2021).
3. Fish microbiota repel ovipositing mosquitoes. Journal of Animal Ecology (2024).
4. Match and mismatch: Integrating consumptive effects of predators, prey traits, and habitat selection in colonizing aquatic insects. Ecology and Evolution (2021).
5. Prey colonization in freshwater landscapes can be stimulated or inhibited by the proximity of remote predators. Journal of Animal Ecology (2020).