Marine algal (seaweed) flora of Terceira Island, Azores

Background As for many other Azorean islands, the macroalgal flora of Terceira (central group of the archipelago) is poorly known, the published information reflecting occasional collections of sporadic visitors to the island. In order to overcome this, and contribute to improve the knowledge of Azorean macroalgal flora at both local and regional scales, a thorough investigation was conducted and both collections and presence data recordings were undertaken at the littoral and sublittoral levels down to approximately 40 m around the island (total area of approximately 49 km2). This paper lists the taxonomic records and provides information on each species’ ecology and occurrence on the island’s littoral. New information A total of 418 specimens (including taxa identified only to genus level) belonging to 147 taxa of macroalgae, comprising 95 Rhodophyta, 33 Chlorophyta and 19 Ochrophyta (Phaeophyceae) are registered. Of these, 113 were identified to species level (73 Rhodophyta, 24 Chlorophyta and 16 Ochrophyta), encompassing 35 new records for the island (27 Rhodophyta, 6 Chlorophyta and 2 Ochrophyta). Most species are native including the Macaronesian endemisms (Codium elisabethiae O.C.Schmidt, Millerella tinerfensis (Seoane-Camba) S.M.Boo & J.M.Rico and Phyllophora gelidioides P.Crouan & H.Crouan ex Karsakoff), eight are introduced and 15 have uncertain origin. Introduction The macroalgal flora of the isolated mid-Atlantic Azores archipelago, as a whole, may be considered relatively rich when compared to that of other remote oceanic islands such as the Shetlands and Faroes in the colder North Atlantic, and Ascension and Tristan da Cunha in the Southern Atlantic (Neto et al. 2005; Tittley & Neto 2005; Wallenstein et al. 2009). With approximately 400 species (Freitas et al. 2019), the Azorean algal flora has been considered cosmopolitan, as it shares species with Macaronesia, North Africa, the Mediterranean Sea, Atlantic Europe and America (Tittley 2003; Tittley & Neto 2006; Wallenstein et al. 2009). The published information, however, reflects data from only a few of the nine islands. Terceira, the second largest island of the central group and the third largest of the archipelago, is among the lesser studied ones. To overcome this and contribute to a better understanding of the seaweed flora of the Azores archipelago, a thorough investigation was conducted in the period between 2000 and 2014, mainly by the Island Aquatic Research Group of the Azorean Biodiversity Centre of the University of the Azores (https://ce3c.ciencias.ulisboa.pt/sub-team/island-aquatic-ecology). In these surveys, special attention was dedicated to the sheet-like and filamentous forms that are difficult to identify in the wild, the seasonal and fast growing annuals, and particularly to the small forms that are often short-lived and fast growing species, very difficult to identify without the aid of a microscope. This paper compiles physical, occurrence and survey data and is intended as a practical resource for biological studies (such as systematics, diversity and conservation, biological monitoring, climate change and ecology), and for academics, students, government, private organizations, and the general public. Purpose By listing the taxonomic records for Terceira and presenting general information for each taxon’s occurrence on the island’s littoral, this paper addresses several biodiversity shortfalls (see Hortal et al. 2015), namely the need to catalogue the Azorean macroalgae (Linnean shortfall) and improve the current information on their local and regional geographic distribution (Wallacean shortfall), as well as on species’ abundances and dynamics in space (Prestonian shortfall).

研究背景 与其他多数亚速尔群岛岛屿类似，特塞拉岛（该群岛中部岛群）的大型藻类区系目前所知甚少，已发表的相关信息仅零星记录了少数到访该岛的人员采集的标本。为填补这一研究空白，助力提升亚速尔群岛区域及本地尺度的大型藻类区系认知水平，本研究开展了系统性调查，在该岛周边潮间带及潮下带（最大采样深度约40 m，全岛总面积约49 km²）范围内完成了标本采集与存在记录工作。本文整理了相关分类学记录，并针对各物种在该岛潮间带的生态特征与分布情况进行了说明。

新数据 本次研究共登记了418份大型藻类标本（包含仅鉴定至属级的分类单元），隶属于147个大型藻类分类单元，其中红藻门（Rhodophyta）95种、绿藻门（Chlorophyta）33种、不等鞭毛藻门（Ochrophyta，褐藻纲Phaeophyceae）19种。在上述类群中，113个单元被鉴定至物种级（红藻门73种、绿藻门24种、不等鞭毛藻门16种），其中包含35个该岛新记录种（红藻门27种、绿藻门6种、不等鞭毛藻门2种）。多数物种为本土物种，其中包含马卡罗尼西亚特有种：Codium elisabethiae O.C.Schmidt、Millerella tinerfensis (Seoane-Camba) S.M.Boo & J.M.Rico以及Phyllophora gelidioides P.Crouan & H.Crouan ex Karsakoff；另有8个为引入物种，15个物种的起源尚不明确。

引言 作为孤立分布于大西洋中部的群岛，亚速尔群岛的大型藻类区系整体而言相对丰富，相较于北大西洋寒带的设得兰群岛、法罗群岛以及南大西洋的阿森松岛、特里斯坦-达库尼亚群岛等偏远大洋岛屿（Neto et al. 2005; Tittley & Neto 2005; Wallenstein et al. 2009），其物种多样性更为可观。据统计，亚速尔群岛的藻类区系约包含400个物种（Freitas et al. 2019），被认为具有广布性特征，其物种与马卡罗尼西亚、北非、地中海、大西洋沿岸欧洲及美洲的类群存在共有类群（Tittley 2003; Tittley & Neto 2006; Wallenstein et al. 2009）。然而已发表的相关数据仅覆盖了该群岛9个岛屿中的少数几个。特塞拉岛作为中部岛群第二大岛、群岛第三大岛，是研究程度较低的岛屿之一。为填补这一研究短板，助力深化对亚速尔群岛海藻区系的认知，研究团队于2000年至2014年间开展了系统性调查，主要工作由亚速尔大学亚速尔生物多样性中心岛屿水生研究组完成（https://ce3c.ciencias.ulisboa.pt/sub-team/island-aquatic-ecology）。本次调查重点关注了野外难以识别的叶状、丝状藻类，季节性速生一年生藻类，以及通常寿命较短、生长迅速且无显微镜辅助难以鉴定的小型藻类类群。本文整合了标本实物信息、分布记录与调查数据，旨在为分类学、多样性与保护学、生物监测、气候变化及生态学等生物学研究，以及科研人员、学生、政府机构、私营组织与普通公众提供实用参考资料。

研究目的 本文通过整理特塞拉岛的大型藻类分类学记录，并阐明各分类单元在该岛潮间带的分布概况，旨在解决当前存在的多项生物多样性缺口问题（详见Hortal et al. 2015），具体包括：完成亚速尔群岛大型藻类的编目工作（林奈缺口（Linnean shortfall）），完善当前关于其本地及区域地理分布的相关数据（华莱士缺口（Wallacean shortfall）），以及补充物种空间丰度与动态的相关信息（普雷斯顿缺口（Prestonian shortfall））。