Understanding Invasive Species in IB ESS
In IB Environmental Systems & Societies (ESS), invasive species are a key topic under ecosystem stability and biodiversity. An invasive species is a non-native organism introduced — intentionally or accidentally — into an ecosystem where it causes harm to the environment, economy, or human health. These species outcompete native organisms, disrupt ecological balance, and reduce biodiversity.
Causes of Invasive Species Introduction
Human activity is the main driver of biological invasions. Species are often transported across regions through:
- Global trade and travel — seeds, insects, and small animals hitchhike in cargo or luggage.
- Agriculture and aquaculture — non-native plants or fish introduced for economic reasons escape containment.
- Pet trade and ornamental gardening — exotic animals or plants released into the wild.
- Climate change — warmer temperatures allow species to expand into new regions.
The IB ESS syllabus emphasizes understanding how human systems interact with natural systems, and invasive species represent a perfect example of this link.
Ecological Impacts of Invasive Species on Ecosystems
Invasive species often outcompete native species for food, light, and habitat. This can trigger a cascade of ecological effects:
- Biodiversity loss: Native species decline or go extinct when unable to compete.
- Disruption of food webs: Predation and competition alter trophic relationships.
- Habitat alteration: Some invasive plants, like kudzu, physically change ecosystem structure.
- Introduction of new diseases: Invasive organisms may carry pathogens that harm local wildlife.
- Ecosystem instability: Energy flow and nutrient cycling become imbalanced.
Example: The zebra mussel (Dreissena polymorpha) invaded North American lakes via ballast water discharge from ships. It clogs pipes, depletes plankton, and outcompetes native mollusks — a case often used in IB ESS case studies on invasive species.
Economic and Social Effects of Invasive Species
- Agricultural damage: Invasive weeds and pests reduce crop yields.
- Infrastructure costs: Control measures and equipment damage raise management expenses.
- Tourism and recreation: Infested lakes, forests, or coastlines deter visitors.
These economic links make invasive species a perfect case for systems thinking in ESS, showing how ecological imbalance affects human sustainability.
Management and Prevention Strategies
IB ESS students must understand both preventive and restorative approaches to invasive species management:
- Prevention: Border control, inspection, and biosecurity policies.
- Early detection and rapid response: Monitoring programs to identify new invasions.
- Biological control: Introducing natural predators (carefully) to control invaders.
- Public awareness: Education to reduce intentional releases and promote ecological responsibility.
These strategies align with IB ESS learning outcomes on sustainability and environmental management.
IB ESS Exam Relevance
Invasive species questions often appear in Paper 2 data-response sections, requiring students to interpret population graphs, ecological impact studies, and system diagrams. Understanding this topic helps demonstrate mastery of biodiversity, resilience, and human-environment interaction — all core IB ESS concepts.
Through RevisionDojo’s IB ESS course, students can access structured notes, diagram-based learning, and exam-style practice focused on real-world case studies like the cane toad in Australia or the lionfish invasion in the Caribbean.
FAQs
What is an invasive species in IB ESS terms?
A non-native organism that establishes, spreads, and causes ecological or economic harm in a new environment.
How do invasive species reduce biodiversity?
They outcompete or prey on native species, disrupt habitats, and alter ecological processes.
How can invasive species be controlled?
Prevention, early detection, biological control, and public education are the most effective management methods.
