- Unsustainable resource use occurs when resource extraction exceeds the natural rate of replenishment.
- This weakens system resilience, increases vulnerability to tipping points, and may result in ecosystem collapse.
- Collapse is often long-term or irreversible, especially when food webs reorganize.
Definition
Ecosystem Collapse
A long-lasting loss of structure, biodiversity, and ecosystem function, where the system shifts to a new, less complex state.
Why Unsustainable Use Happens
- Over-consumption due to population growth and rising economic demand.
- Industrial-scale extraction technologies (e.g., factory trawlers, mechanized deforestation).
- Weak environmental governance (inadequate quotas, enforcement gaps).
- Profit-driven decision-making prioritizing short-term gain over long-term sustainability.
Analogy
- Think of natural resources like a bank account.
- Sustainable use = spending only the interest.
- Unsustainable use = spending the capital → eventually the account becomes empty.
Consequences of Unsustainable Resource Use
- Loss of biodiversity
- Reduction of ecosystem services (e.g., food provision, coastal protection, water filtration)
- Food web instability and trophic cascades
- Loss of livelihood and cultural identity for dependent communities
Case study
Collapse of the Newfoundland Cod Fishery (Canada)
Background
- The Grand Banks off Newfoundland were once among the richest cod fisheries in the world.
- Sustained local fishing supported coastal communities for centuries.
Shift to Unsustainability
- 1950s-1980s: Industrial fishing fleets introduced:
- Factory trawlers capable of catching thousands of tonnes.
- Sonar tracking to locate schools rapidly.
- Bottom trawling damaging seafloor habitats.
- Catch rates rose artificially even as cod populations began to decline.
Collapse
- 1992: Cod stocks fell to less than 1% of their historical biomass.
- Canadian government issued a moratorium (ban) on cod fishing.
- Expected recovery time: 3–5 years.
- Actual recovery: still incomplete decades later.
Ecological Consequences
- Cod acted as a keystone predator.
- Removal led to:
- Population increase in shrimp and small fish
- Shift in trophic interactions
- New stable state formed without cod → recovery is blocked.
Social and Economic Impacts
- 30,000+ fishery workers lost livelihoods.
- Rural coastal communities suffered depopulation and long-term unemployment.
- Cultural identity linked to fishing was disrupted.
Why Recovery Did Not Occur
- Too few mature breeding fish remained.
- Alternative species (shrimp/crab) expanded and outcompete juvenile cod.
- The ecosystem reorganized, so cod no longer holds its previous niche.
Connections to Sustainability
- Sustainable resource management depends on maintaining renewable yield, the rate at which a resource can naturally regenerate.
- Overexploitation reduces resilience and pushes ecosystems beyond tipping points.
- The collapse of one system can trigger cascading failures in others (e.g., economic, social, and cultural).
Other Examples of Unsustainable Resource Use
| Resource | Example | Impact |
|---|---|---|
| Timber | Amazon Deforestation | Biodiversity loss + climate feedback. |
| Coral reef | Dynamite/Cyanide Fishing | Habitat collapse + reduced fish nurseries. |
| Soil | Overcultivation in drylands | Soil erosion + desertification. |
| Wildlife Trade | Madagascar reptiles | Population decline and local extinction. |
Self review
- Explain how unsustainable resource use leads to ecosystem collapse.
- Using the Newfoundland cod case, explain how technological change contributed to resource overexploitation.
- Outline two ecological consequences of the collapse of the cod fishery.
