Inventory biodiversity indices such as species richness, distribution of species’ abundances or evenness in communities, and those that represent functional characteristics provide foundational information that can be used to formally evaluate the ecological role species fulfill within ecosystems. Describing changes in the dimensions of biodiversity relative to spatiotemporal and environmental gradients facilitates more refined and integrated views of community dynamics. This study synthesized fisheries-independent bottom longline survey data collected from 1990 to 2018 to elucidate patterns in six inventory biodiversity indices across temporal, small-scale spatial, and thermal domains for the shark community inhabiting the Mid-Atlantic Bight. Model-based predictions over years showed marked increases since the mid-2000s in several indices and were suggestive of an expanding community in terms of species richness, biodiversity, relative abundance, functional traits, and size composition. Annual relative evenness predictions were fairly constant and indicative of persistent maintenance in the distribution of community abundance across taxa through time. Changes in the biodiversity indices were also evident across a fairly small spatial area and in response to bottom water temperature, although patterns were less prominent when compared to interannual trends. The results of this study complement single-species population analyses by providing a community-level perspective, and offer positive indications that the shark community off the U.S. east coast has become more robust over the past several years.

中文翻译：

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中大西洋湾鲨鱼群落动态

清单生物多样性指数，如物种丰富度、物种丰度或群落均匀度的分布，以及代表功能特征的指数，提供了可用于正式评估物种在生态系统中发挥的生态作用的基础信息。描述与时空和环境梯度相关的生物多样性维度的变化有助于更精细和综合地看待社区动态。本研究综合了 1990 年至 2018 年收集的独立于渔业的海底延绳钓调查数据，以阐明居住在大西洋中部海湾的鲨鱼群落的时间、小尺度空间和热域的六个清单生物多样性指数的模式。多年来基于模型的预测显示，自 2000 年代中期以来，几个指数显着增加，表明群落在物种丰富度、生物多样性、相对丰度、功能特征和大小组成方面不断扩大。年度相对均匀度预测相当稳定，表明随着时间的推移，整个分类群的群落丰度分布持续保持。生物多样性指数的变化在相当小的空间区域内也很明显，并且响应底层水温，尽管与年际趋势相比，模式不那么突出。这项研究的结果通过提供社区层面的观点补充了单一物种种群分析，并提供了美国以外的鲨鱼社区的积极迹象