Century-scale species incidence, rareness and turnover in a high-diversity Northwest Atlantic coastal embayment

摘要: The increased chance of extinction for rare species jeopardizes the resilience high-diversity coastal ecosystems where uncommon often hold key roles that sustain ecosystem functioning. Rare can support most vulnerable functions an ecosystem, occupy niches more common are unable to fill, and have significant, disproportionate effects on higher trophic levels when lost. Therefore, detecting marine extinctions at any spatial scale is a priority. deep (approx. two centuries) zoological record Cobscook Bay, USA, biological hotspot in Northwest Atlantic, provides opportunity assess rareness turnover ecosystem. This well-studied macrotidal embayment lower Bay Fundy has 874 macroinvertebrate known from 3,767 records, extrapolated maximum richness approximately 1,175 species. chronology its historical incidence features some striking patterns. Approximately one-third identified yet be confirmed, with 88 last seen prior 1900. Sampling effort, ranges, endemicity stochastic larval settlement do not adequately explain why so many rare. Instead, evidence late 20th-century coincident diversification intensification commercial fisheries suggests local primary cause rareness. In addition, present-day assemblages significantly altered taxonomic structure composition. implications loss stability function this highly productive estuary illustrate need ecological conservation protect substantial contribution biodiversity Gulf Maine.