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beautiful shell colours and patterns of the Cuban snail Polymita picta. International trade of this species is prohibited by the Convention on International Trade in Endangered Species. Photo Credit: B. Reyes-Tur. |
Scientific Frontline: Extended "At a Glance" Summary
The Core Concept: A comprehensive scientific review quantifying the catastrophic loss of biodiversity among Pacific Island land snails, revealing that extinction rates on high volcanic islands range from 30% to 80% of total species.
Key Distinction/Mechanism: Unlike standard biodiversity assessments that rely on living populations, this research utilizes the "shell bank"—shells preserved in the soil for centuries. This mechanism allows scientists to identify and catalog "silent extinctions" of species that vanished before they could be formally described by modern science.
Origin/History: Published in Philosophical Transactions of the Royal Society B, the study traces the timeline of these extinctions to two primary waves: the initial arrival of humans on the islands and the subsequent, more extensive impact of Western colonization.
Major Frameworks/Components:
- The Shell Bank: A fossil-like record of calcium carbonate shells used to reconstruct pre-human biodiversity baselines.
- Invasive Predation: Identification of key biological drivers of extinction, specifically rats, the rosy wolf snail (Euglandina), and the New Guinea flatworm (Platydemus manokwari).
- Habitat Alteration: The correlation between deforestation/land-use change and the collapse of endemic populations.
- Extinction Trajectories: A model distinguishing between "natural" background extinction (e.g., via fossilized dunes) and the accelerated anthropogenic rates observed recently.
- Branch of Science: Conservation Biology, Malacology (the study of mollusks), and Island Biogeography.
Future Application: Data from this review supports the development of urgent captive breeding programs ("buying time") and argues for a revision of global conservation agendas to prioritize non-charismatic invertebrates often overlooked in biodiversity crises.
Why It Matters: This research corrects the historical record, demonstrating that global extinction estimates are likely severe underestimates. By documenting species that were lost before they were found, it highlights the extreme vulnerability of island ecosystems to invasive species and human activity.