Driver-Passenger Invasion Model / 驅動者與搭便車模型

Definition

Driver-passenger invasion model is the causal distinction between alien species acting as direct drivers of native-species decline and alien species expanding as passengers of broader habitat or environmental change.

Current Synthesis

The Duanwen episode uses the model to make Taiwan’s introduced-myna debate more cautious. If introduced mynas are direct drivers, removal may address the main cause of native-bird decline. If they are passengers of urbanization, forest reduction, building expansion, or other landscape change, removal alone may not restore native populations.

The model matters because management follows diagnosis. A direct-driver case supports targeted removal more strongly; a passenger case points toward habitat repair, monitoring, and site-specific control rather than blanket killing.

Key Claims

• Driver explanations attribute native decline directly to predation, competition, or other impacts from the introduced species.
• Passenger explanations attribute both alien expansion and native decline to external environmental change.
• Misdiagnosing passengers as drivers can waste resources and produce killing without recovery.
• Taiwan’s introduced-myna evidence remains too limited for a confident direct-driver conclusion.

Evidence

• Model definition: 「人人喊打」的八哥，與台灣的「外來物種」難題 contrasts direct-driver and passenger explanations.
• Canberra comparison: 「人人喊打」的八哥，與台灣的「外來物種」難題 cites a 2014 Canberra common myna study as more consistent with the passenger model.
• Taiwan caution: 「人人喊打」的八哥，與台灣的「外來物種」難題 says Taiwan lacks detailed evidence to settle strong introduced-myna interaction claims.

Counterevidence & Qualifications

The source does not conclude that Taiwan mynas are harmless passengers. It says the stronger direct-causality claim needs more research and should not be assumed from alien status alone.

What Changed

• Created the causal-model concept from the introduced-myna discussion.

Related Concepts

• Invasive Species Management - management framework shaped by driver or passenger diagnosis.
• Taiwan Myna Management / 台灣外來八哥管理 - Taiwan case where the model changes likely interventions.
• Urban Ecology - external-change context that can make alien species passengers.
• Observation Before Inference - adjacent reasoning principle for avoiding story-first causality.