In AP Environmental Science, a disturbance is a natural or human-caused event (fire, flood, hurricane, volcanic eruption) that disrupts an ecosystem, and per EK ERT-2.G.1 a natural disturbance can have environmental consequences as great as or greater than a human-made one.
A disturbance is any sudden, significant event that shakes up an ecosystem. Think wildfire, flooding, hurricanes, volcanic eruptions, drought, or major shifts in sea level. The AP CED groups these under "Natural Disruptions to Ecosystems" (Topic 2.5), and the headline idea is in EK ERT-2.G.1: a natural disturbance can hit an ecosystem just as hard, or harder, than something humans cause.
The key thing to track is timing. Earth system processes run on different schedules (EK ERT-2.G.2). Some are periodic (regular, like seasonal tidal flooding), some are episodic (occasional but irregular, like a hurricane every few decades), and some are random. Disturbances also play out over wildly different timescales. A fire is over in days, but climate shifting over geological time (EK ERT-2.G.3) or sea level rising and falling as glacial ice melts and refreezes (EK ERT-2.G.4) unfolds over thousands of years. Big disturbances commonly trigger major environmental change and upheaval (EK ERT-2.G.5).
Disturbance lives in Unit 2: The Living World: Biodiversity, specifically Topic 2.5, and it's the backbone of learning objective AP Enviro 2.5.A: explain how natural disruptions, both short- and long-term, impact an ecosystem. This term is the engine behind a lot of Unit 2 reasoning. Disturbances knock ecosystems off balance, which is exactly what tests an ecosystem's resilience and kicks off ecological succession. If you understand disturbance, you understand why ecosystems change over time instead of staying frozen in one state.
Keep studying AP® Environmental Science Unit 2
Ecosystem Resilience (Unit 2)
Resilience is basically an ecosystem's ability to bounce back after a disturbance. The disturbance is the punch; resilience is whether the ecosystem gets back up. A system that has evolved with regular natural disturbances (like fire-adapted forests) usually recovers far better than one hit by something it has never faced.
Community Resilience (Unit 2)
Same idea zoomed in to the community of species. After a disturbance wipes out part of a community, the surviving species and the order they recolonize determine how fast the community reassembles. Frequent, low-intensity disturbances often keep diversity high instead of letting one species dominate.
Sea Level Rise (Units 2 & 9)
Sea level change is a slow, long-term disturbance. EK ERT-2.G.4 ties sea level to how much glacial ice Earth holds, which connects Unit 2 ecosystem disruption straight to the climate change content in Unit 9. Coastal wetlands face both fast disturbances (hurricanes) and this slow one at the same time.
Multiple-choice stems love to test whether you can classify a disturbance by its timing and predict the long-term outcome. Expect questions like a coastal wetland hit by a hurricane at natural historical frequency (the right answer is usually that the ecosystem recovers, because it evolved with that disturbance regime) or a scenario describing biweekly tidal flooding, occasional storm surges, and rare hurricane damage, which is asking you to sort periodic versus episodic versus rare events. A classic one drops volcanic ash on a forest and asks for the long-term impact, where you'd reason toward succession and eventual recovery. On FRQs, disturbance shows up through related setups, like the 2021 FRQ on habitat destruction and fragmentation and the 2023 SAQ floodplain experiment. You should be able to describe how a disturbance affects an ecosystem and connect it to resilience and succession.
A disturbance is the event itself, the fire or flood that disrupts things. Resilience is the ecosystem's response, how well it recovers afterward. Don't mix them up: the disturbance happens TO the ecosystem, and resilience describes whether the ecosystem can take the hit and come back. Same scenario, two different roles.
A disturbance is a sudden, significant event (fire, flood, hurricane, volcano, sea level change) that disrupts an ecosystem.
EK ERT-2.G.1 says natural disturbances can have consequences as great as or greater than human-caused ones.
Disturbances run on different timescales and patterns: periodic (regular), episodic (occasional/irregular), and random.
Ecosystems adapted to a natural disturbance regime usually recover, which is the link between disturbance and resilience.
Slow disturbances matter too: climate shifts over geological time and sea level changes from melting glacial ice both disrupt ecosystems over long periods.
It's a sudden, significant event that disrupts an ecosystem, like a wildfire, flood, hurricane, or volcanic eruption. The CED covers it in Topic 2.5 under learning objective AP Enviro 2.5.A.
No. EK ERT-2.G.1 specifically says a natural disturbance, for a given event, can be as damaging as or even more damaging than a human-made disruption. A single volcanic eruption or hurricane can devastate an ecosystem.
A disturbance is the disrupting event itself, while resilience is the ecosystem's ability to recover afterward. The disturbance happens to the ecosystem; resilience measures how well it bounces back.
Per EK ERT-2.G.2, periodic disturbances happen on a regular schedule (like biweekly spring tides), episodic ones happen occasionally and irregularly (like a hurricane every few decades), and random ones have no predictable pattern.
It's a slow, long-term disturbance. EK ERT-2.G.4 explains that sea level has varied a lot over geological time as the amount of glacial ice on Earth changes, gradually reshaping coastal ecosystems.
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