| Front | Back | | --- | --- | | How does functional redundancy within a biodiverse ecosystem prevent collapse after a species declines? |

Multiple species perform similar ecological roles (e.g., multiple pollinators).
If one species declines, others can fill its niche, maintaining energy flow and nutrient cycling.

| | How does genetic diversity within a single species enhance the resilience of the wider ecosystem? |

It provides a wider pool of traits, increasing the likelihood that some individuals survive abiotic stress (e.g., drought, disease).
This prevents the extinction of key species, preserving ecosystem structure.

| | Why are complex food webs more resilient to disturbances than simple monocultures? |

Energy pathways are highly interconnected, offering alternative food sources if one prey species is lost.
This prevents a trophic cascade (chain-reaction extinctions) from dismantling the system.

| | Explain the relationship between ecological succession, biodiversity, and ecosystem stability. |

As succession progresses, species and habitat diversity increase.
This increases trophic complexity and functional redundancy.
Resulting in higher resilience and greater overall ecosystem stability.

| | Using the Amazon rainforest as a case study, how can human-driven deforestation lead to a permanent state change? |

Removing canopy cover alters the microclimate and erodes nutrient-rich topsoil.
This loss of resilience shifts the system into a dry, savanna-like alternative stable state.

| | Why does intensive agriculture drastically lower the resilience of a soil ecosystem? |

It replaces diverse communities with monocultures, reducing genetic and species diversity.
Soil compaction and fertilizer use disrupt natural nutrient cycling and water infiltration.

| | Why is ecosystem recovery after mining typically much slower than recovery after a natural forest fire? |

Mining completely removes topsoil and microbial communities, severely altering abiotic conditions.
Forest fires leave soil structures and seed banks intact, allowing rapid secondary succession.

| | How can frequent, uncontrolled burning shift a forest ecosystem into an alternative stable state? |

It destroys the soil seed bank and alters natural nutrient cycles.
This prevents forest regeneration, leading to permanent replacement by grassland.

| | How does the transition of a coral reef to an algal-dominated system illustrate an alternative stable state? |

Overfishing and ocean acidification push the reef past a critical tipping point.
The system reorganizes into a new equilibrium with lower biodiversity and altered ecological functions.

| | Compare how an ecocentric and an anthropocentric forest manager might approach fire management. |

Ecocentric: Allows natural or controlled fires to promote natural succession and maintain biodiversity.
Anthropocentric: Prioritizes fire suppression to protect timber resources, economic infrastructure, and human safety.

| | Why is human intervention (e.g., active ecological restoration) often required to return a system from an alternative stable state? |

The new state is a stable equilibrium protected by new feedback loops.
Natural recovery mechanisms are lost, requiring external energy/resources to cross back over the threshold.

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In this "ball-and-cup" model of ecosystem resilience, what does the width and depth of the basin represent, and how does this affect the system's response to a shock?

The width/depth represents the ecosystem's resilience (capacity to absorb disturbance).
A wider/deeper basin means the system can tolerate larger shocks without shifting into a new state.

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Based on this diagram, what happens to the system when a disturbance pushes the "ball" past the tipping point, and why is recovery difficult?

The system rolls into a new basin, representing an alternative stable state.
Recovery is difficult because the new state is stable, requiring significant energy or human intervention to push it back.

| | An ecosystem's ability to maintain its structure and function over time, even when facing stress or disturbances, is defined as stability, whereas its ability to recover and return to its original state after a disturbance is called resilience. | An ecosystem's ability to maintain its structure and function over time, even when facing stress or disturbances, is defined as stability, whereas its ability to recover and return to its original state after a disturbance is called resilience. | | When an ecosystem crosses an ecological threshold, it shifts into an alternative stable state, which typically features lower biodiversity and reduced productivity. | When an ecosystem crosses an ecological threshold, it shifts into an alternative stable state, which typically features lower biodiversity and reduced productivity. | | What is the term for the variety of ecological roles or processes (such as pollination, decomposition, and nitrogen fixation) performed by species in an ecosystem? | Functional diversity. | | How does habitat diversity cushion an ecosystem against large-scale collapse? |

It offers multiple ecological niches for species to inhabit.
Different habitats recover at different rates, preventing simultaneous, total system failure.

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| System has low resilience | |

| System has high resilience | |

| New equilibrium | |

| The system |

Topic 1: Foundation 3 subtopics

Topic 2: Ecology5 subtopics

Topic 3: Conservation and biodiversity3 subtopics

Topic 4: Water4 subtopics

Topic 5: Land2 subtopics

Topic 6: Atmosphere and climate change4 subtopics

Topic 7: Natural resources3 subtopics

Topic 8: Human populations and urban systems3 subtopics

IB Environmental systems and societies 2.5C Ecosystem Resilience Flashcards

Flashcards for 2.5C Ecosystem resilience

Flashcards for 2.5C Ecosystem resilience - IB