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Biodiversity and Ecosystem Stability
Biodiversity and Ecosystem Stability
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Biodiversity is the variety of life in an ecosystem, including different species, genes, and habitats. Ecosystem stability is the ability of that system to keep functioning when conditions change or disturbances occur. In general, ecosystems with more biodiversity are better able to resist damage and recover after stress. This matters because stable ecosystems support food webs, clean water, soil health, and climate regulation.
Biodiversity improves stability because many organisms perform overlapping roles, so one species can partly compensate if another declines. Complex food webs also spread energy and interactions across many pathways, which reduces the chance that one loss will collapse the whole system. Genetic diversity helps populations survive disease, drought, and temperature shifts. Habitat diversity creates more niches, which supports more species and strengthens ecosystem resilience over time.
Key Facts
- Higher species richness often increases resilience, resistance, and recovery after disturbance.
- Net primary productivity can support biodiversity because more available energy can support more trophic levels.
- If one species is lost, functional redundancy means another species with a similar role may help maintain ecosystem processes.
- Diverse food webs are often more stable because energy can flow through multiple pathways.
- Population growth can be modeled as dN/dt = rN(1 - N/K), where biodiversity can influence r and ecosystem carrying capacity K indirectly.
- A simple diversity measure is species richness = number of species present in an ecosystem.
Vocabulary
- Biodiversity
- Biodiversity is the variety of living organisms, genes, and ecosystems in a given area.
- Ecosystem stability
- Ecosystem stability is the ability of an ecosystem to maintain its structure and function over time, even after disturbance.
- Resilience
- Resilience is the capacity of an ecosystem to recover after a disruption such as fire, drought, or pollution.
- Functional redundancy
- Functional redundancy means multiple species perform similar ecological roles, so the ecosystem can keep working if one is lost.
- Food web
- A food web is a network of feeding relationships that shows how energy and matter move through an ecosystem.
Common Mistakes to Avoid
- Assuming more individual organisms always means more biodiversity, which is wrong because biodiversity depends on variety of species, genes, and habitats, not just total population size.
- Thinking every ecosystem with low biodiversity is unhealthy, which is wrong because some natural ecosystems have fewer species but can still be stable under their normal conditions.
- Confusing resilience with resistance, which is wrong because resistance means avoiding change during disturbance, while resilience means recovering after change happens.
- Believing the loss of one species never matters if many others remain, which is wrong because some species are keystone species whose removal can strongly disrupt the whole ecosystem.
Practice Questions
- 1 An ecologist surveys two grasslands. Grassland A has 12 plant species, and Grassland B has 5 plant species. If a drought kills 2 species in each grassland, what percentage of the original plant species remains in each grassland, and which grassland is likely to be more stable?
- 2 A pond food web has 8 species. Pollution removes 3 species that all eat algae. How many species remain, and why might having several algae-eating species have helped the pond before pollution occurred?
- 3 Explain how genetic diversity, species diversity, and habitat diversity each contribute to ecosystem stability during environmental change.