Abstract To effectively manage anthropogenic stressors causing widespread and pervasive habitat change, resource managers and policy makers require advice on priority stressors to optimally target conservation and restoration outcomes. This is difficult in soft sediment ecosystems affected by multiple stressors operating across centuries with possible legacy interactions. Using tools from the emerging discipline of conservation paleobiology, we attempted to disentangle the effects of two stressors: i) changes to sediments (sedimentation rate, composition) and ii) fishing disturbance across pre-human to contemporary timescales by analysing death assemblages (DA) at a rare location protected from power fishing methods for ca. 30 yr in Nelson Bays, Aotearoa-New Zealand. Replicate sediment cores and surface grab samples were collected at paired stations, spread across three depth profiles (25, 30, 35 m), split inside and outside the fishing exclusion zone. Sediment core geochronologies were established using radioisotope dating and analysis of terrestrial plant palynomorphs (spores, pollen, starch) associated with Māori and European introduction to Aotearoa-New Zealand. Results unearthed a complex of brachiopods, molluscs, crustacea, bryozoan, and Māori-introduced pollen and starch remains – the latter a marine first. Following human arrival in the region (ca.1500AD) statistical models revealed separation of DAs between time periods were correlated with a 10–15% increase in sediment silt content following a ca.11-fold increase in Sediment Accumulation Rates (SAR). In contrast, separation of recent surface DAs (ca. 60yr) are now more strongly correlated with sediment mixing, detected by discordance in radioisotope profiles, consistent with exposure to homogenising effects of fishing disturbance outside the exclusion zone. We conclude that historic legacy effects, ongoing sedimentation and fishing disturbance have synergistically modified the sediment characteristics from “natural” baseline conditions. Those changes have likely contributed to the collapse and lack of recovery of Nelson Bays shellfish fisheries.

中文翻译：

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从沉积岩芯和死亡组合中检测到的粒度和物种组成的历史和当代人为影响，纳尔逊湾，新西兰

摘要 为了有效管理导致广泛和普遍栖息地变化的人为压力因素，资源管理者和政策制定者需要关于优先压力因素的建议，以最佳地针对保护和恢复结果。这在受多个压力源影响的软沉积物生态系统中很困难，这些压力源跨世纪运行，可能存在遗留相互作用。使用来自保护古生物学新兴学科的工具，我们试图解开两个压力因素的影响：i) 沉积物的变化（沉积率、成分）和 ii) 通过分析死亡组合 (DA) 对人类前到现代时间尺度的捕捞干扰在一个罕见的地方，可以避免使用电动捕鱼方法。在新西兰 Aotearoa 的 Nelson Bays 工作 30 年。在成对的站点收集了重复的沉积物岩心和表面抓取样本，分布在三个深度剖面（25、30、35 m），在捕捞禁区内外分开。沉积物核心地质年代学是使用放射性同位素测年和分析与毛利人和欧洲引入新西兰的陆生植物孢粉体（孢子、花粉、淀粉）相关的。结果出土了腕足类动物、软体动物、甲壳类动物、苔藓动物和毛利人引入的花粉和淀粉残骸的复合体——后者首先是海洋生物。人类到达该地区后（约公元 1500 年）统计模型显示，在沉积物积累率 (SAR) 增加约 11 倍后，不同时期内 DA 的分离与沉积物淤泥含量增加 10-15% 相关。相比之下，最近的表面 DA 的分离（约 60yr) 现在与沉积物混合更密切相关，通过放射性同位素分布的不一致检测到，与禁区外捕捞干扰的均质效应暴露一致。我们得出的结论是，历史遗留影响、持续的沉积和捕捞干扰协同改变了“自然”基线条件下的沉积特征。这些变化可能导致纳尔逊湾贝类渔业的崩溃和缺乏恢复。持续的沉积和捕捞干扰协同改变了“自然”基线条件下的沉积特征。这些变化可能导致纳尔逊湾贝类渔业的崩溃和缺乏恢复。持续的沉积和捕捞干扰协同改变了“自然”基线条件下的沉积特征。这些变化可能导致纳尔逊湾贝类渔业的崩溃和缺乏恢复。