Overview

Predator-prey dynamics describe the interactions between two species: one (the predator) that hunts, kills, and consumes the other (the prey). These relationships are fundamental to ecosystem stability, influencing population sizes, biodiversity, and the flow of energy through food webs.

Key Concepts

1. Population Oscillations

  • Lotka-Volterra Model: Classic mathematical model illustrating cyclical fluctuations in predator and prey populations.
  • Feedback Loops: An increase in prey leads to more predators; as predators consume prey, prey numbers decline, causing predator numbers to fall, allowing prey to recover.

2. Functional and Numerical Responses

  • Functional Response: Change in predator feeding rate as prey density changes.
  • Numerical Response: Change in predator population size as prey density changes.

3. Trophic Cascades

Predator-prey interactions can cause indirect effects across multiple trophic levels. Removing predators may lead to prey overpopulation and depletion of vegetation.

4. Coevolution

Predators and prey often evolve in response to each other. Prey may develop camouflage, speed, or toxins, while predators may evolve better senses, speed, or resistance to toxins.

Diagram: Predator-Prey Cycle

Predator-Prey Cycle

Surprising Facts

  1. Predators Can Increase Biodiversity: By controlling dominant prey species, predators can prevent competitive exclusion, allowing more species to coexist.
  2. Prey Shape Ecosystems: Some prey, like beavers, dramatically alter habitats, affecting predator populations and overall ecosystem structure.
  3. Predator-Prey Relationships Exist in Microbial Worlds: Viruses (“predators”) regulate populations of bacteria (“prey”) in oceans, influencing global nutrient cycles.

Environmental Implications

1. Ecosystem Stability

  • Keystone Species: Predators like wolves or sharks are keystone species. Their removal can collapse food webs and reduce biodiversity.
  • Invasive Species: Introduction of non-native predators or prey can disrupt established dynamics, causing extinctions and ecosystem shifts.

2. Human Impact

  • Habitat Fragmentation: Reduces prey availability and predator range, destabilizing populations.
  • Overhunting: Decreases predator numbers, leading to prey overpopulation and habitat degradation.

3. Pollution Effects

Plastic pollution, now found in the deepest ocean trenches (see Peng et al., 2020), affects predator-prey dynamics by:

  • Bioaccumulation: Toxins accumulate in prey, affecting predator health and reproduction.
  • Behavioral Changes: Pollutants can alter prey behavior, making them more vulnerable or less detectable to predators.

Emerging Technologies

1. Remote Sensing and AI

  • Tracking Movements: Satellite tags and drones monitor real-time predator and prey migrations.
  • AI Modeling: Machine learning predicts population changes and ecosystem responses to environmental stressors.

2. Environmental DNA (eDNA)

  • Non-invasive Monitoring: eDNA samples from water or soil reveal presence of predators and prey, even at low densities.

3. Autonomous Underwater Vehicles (AUVs)

  • Deep Sea Exploration: AUVs detect predator-prey interactions in extreme environments, such as abyssal plains and deep ocean trenches.

Case Study: Plastic Pollution in Deep Ocean Predator-Prey Dynamics

Recent research (Peng et al., 2020) has documented plastic debris in the Mariana Trench, the world’s deepest ocean region. Plastics ingested by prey species (e.g., amphipods) are transferred up the food chain, affecting predators like deep-sea fish. This bioaccumulation can impair growth, reproduction, and survival, altering traditional predator-prey cycles.

Glossary

  • Predator: An organism that hunts and consumes another organism.
  • Prey: An organism that is hunted and consumed by a predator.
  • Lotka-Volterra Model: Mathematical equations describing predator-prey population cycles.
  • Trophic Cascade: Ripple effect across food web levels caused by changes in predator or prey populations.
  • Keystone Species: A species with a disproportionately large effect on ecosystem structure.
  • Bioaccumulation: Build-up of substances (like toxins) in organisms over time.
  • eDNA (Environmental DNA): Genetic material collected from environmental samples, used to detect species presence.
  • AUV (Autonomous Underwater Vehicle): Robot used for underwater exploration and data collection.

References

  • Peng, X., et al. (2020). “Microplastics in the marine environment: Sources, distribution, biological effects, and solutions.” Science of The Total Environment, 698, 134254. Link
  • Lotka, A. J. (1925). “Elements of Physical Biology.”
  • Volterra, V. (1926). “Fluctuations in the abundance of a species considered mathematically.”

Summary Table

Concept Description Environmental Implication
Population Oscillation Cyclical changes in predator/prey numbers Biodiversity, stability
Trophic Cascade Indirect effects across food web Habitat change, species loss
Coevolution Reciprocal evolutionary adaptations Species resilience
Plastic Pollution Disrupts predator-prey health and interactions Food web contamination
Emerging Technologies New ways to monitor and model dynamics Improved conservation

Further Reading

End of Study Notes