Background The macroalgal flora of Graciosa (central group of Azores archipelago) is poorly known, the published information reflecting occasional collections from sporadic field visits to the island. To overcome this, a thorough investigation under the Expedition “GRACIOSA/2004”, the Campaigns “PADEL/2006”, “MACROBIOLMOL/2014” and “PIMA-BALA/2017” involving sample collecting and presence data recording, was undertaken over an area of 19 km2 encompassing littoral and sublittoral levels down to about 40 m. This paper lists the taxonomic records and provides information on species ecology and occurrence around the island improving the knowledge of the Azorean macroalgal flora at both local and regional scales.
New information A total of 1692 specimens belonging to 250 taxa of macroalgae (and including 55 taxa identified only at the genus level) are registered, comprising 166 Rhodophyta, 36 Chlorophyta and 48 Ochrophyta (Phaeophyceae). From these, 195 are identified to the species level (126 Rhodophyta, 31 Chlorophyta and 38 Ochrophyta) and comprise 156 native, 20 of uncertain origin and 14 introductions to the island. Predaea feldmannii subsp. azorica Gabriel is an Azorean endemic, whereas Codium elisabethiae O.C. Schmidt, Botryocladia macaronesica Afonso-Carrillo, Sobrino, Tittley & Neto, Phyllophora gelidioides P.Crouan & H.Crouan ex Karsakoff and Laurencia viridis Gil-Rodríguez & Haroun represent Macaronesian endemics. Seventy-nine species are newly recorded to the island.
Introduction Around 400 species have been recorded in the isolated mid-Atlantic Azores archipelago so far (Freitas et al. 2019). When compared to that of other remote oceanic islands (e.g. the Shetlands and Faroes in the colder North Atlantic, and Ascension and Tristan da Cunha in the Southern Atlantic), the algal flora of the Azores can be considered relatively rich (Tittley 2003, Neto et al. 2005; Tittley & Neto 2005; Tittley & Neto 2006, Wallenstein et al. 2009). It is a cosmopolitan flora with species shared with Macaronesia, North Africa, the Mediterranean Sea, Atlantic Europe and America. Overall, it shares more species with the east Atlantic flora than with the west (Tittley & Neto 2006, Wallenstein et al. 2009). Although São Miguel has been thoroughly investigated, most of the Azorean islands have received little attention, there algal flora being scarcely studied. To overcome this, and improve the understanding of the archipelago’s seaweed flora, research has been conducted over the past three decades. This paper presents both physical and occurrence data, and information gathered from macroalgae surveys undertaken on Graciosa (central group of the archipelago) 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) the MARBE, Marine Biodiversity and Environment Research Group of CIBIO-Açores at the University of the Azores (http://cibio.uac.pt/en/research-groups/marbe-marine-biodiversity-and-environment), and the OKEANOS Centre of the University of the Azores (www.okeanos.uac.pt). In these surveys particular attention was given to the small filamentous and thin sheet like forms that are often short-lived and fast-growing species, very difficult to identify in the wild, requiring the aid of a microscope. The paper aims to provide a practical resource for biological studies, such as systematics, diversity and conservation, biological monitoring, climate change and ecology, and also for academics, students, government, private organizations, and the general public.
Purpose In this contribution we list taxonomic records for Graciosa and present general information for the occurrence of each taxon around the island. By doing this, we are contributing to address 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).
The data in this sampling event resource has been published as a Darwin Core Archive (DwC-A), which is a standardized format for sharing biodiversity data as a set of one or more data tables. The core data table contains 50 records.
1 extension data tables also exist. An extension record supplies extra information about a core record. The number of records in each extension data table is illustrated below.
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Neto A I, Parente M I, Botelho A Z, Prestes A C L, Resendes R, Afonso P, Álvaro N V, Milla-Figueras D, Neto R M A, Tittley I, Moreu I (2020): Marine algal (seaweed) flora of Graciosa Island, Azores. v1.9. Universidade dos Açores. Dataset/Samplingevent. http://ipt.gbif.pt/ipt/resource?r=graciosa_seaweed_flora&v=1.9
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Macroalgae; seaweeds; Rhodophyta; Chlorophyta; Ochrophyta; Azores; Graciosa Island; endemism; native; uncertain; introduced; occurrence data.; Samplingevent
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Graciosa Island, Azores, Macaronesia, Portugal (approximately 39°0′38″N, 27°59′1″W .
|Bounding Coordinates||South West [39.002, -28.076], North East [39.104, -27.927]|
All macroalgae were identified to genus or species level. In total, 250 taxa were identified belonging to 31 orders and 66 families, distributed by the phyla Rhodophyta (17 orders and 41 families), Chlorophyta (4 orders and 9 families) and Ochrophyta (9 orders and 16 families).
|Phylum||Rhodophyta (Red algae), Chlorophyta (Green algae), Ochrophyta (Brown algae)|
|Start Date / End Date||2004-01-01 / 2017-01-01|
Aimed at improving the knowledge of Graciosa Island macroalgal flora, extensive observations were made in the period between 2004 and 2017, encompassing both collections and presence data recording in a relatively large area covering the littoral and sublittoral levels down to approximately 40 m around the island. This paper lists the taxonomic records and provides information on each species ecology and occurrence on the island littoral.
|Title||Marine algal (seaweed) flora of Graciosa Island, Azores|
|Identifier||Seaweeds of Graciosa Island (Azores)|
|Funding||This study was mainly financed by the following projects/scientific expeditions: • Expedition GRACIOSA/2004, Departamento de Biologia da Universidade dos Açores Ilha do Pico, Açores, June 2004; • Campaign PADEL/2006, under the project “PADEL: Património natural e desenvolvimento sustentável do litoral dos Açores: a Ilha Graciosa como caso de estudo”. 2006 - 2007. The Azores Regional Government; • Campaign MACROBIOMOL/2014, under the project “MACROBIOMOL, Macroalgal biodiversity under molecular lens - towards a better understanding of North Atlantic biogeography” (PTDC/MAR/114 613/2009). 2011 - 2015. Operational Program COMPETE (ERDF funds), FCT (UID/BIA/50027/2013) and POCI-01-0145-FEDER-006821; • Campaign PIMA-BALA/2017, under the projects “PIMA (3/DRAM/2015), Elaboração do programa de implementação da Diretiva-Quadro Estratégia Marinha - Programa invasoras marinhas nos Açores” and “BALA (2/DRAM/2015), Elaboração do programa de implementação da diretiva-quadro estratégia marinha - biodiversidade dos ambientes litorais dos Açores”. ERDF funds, and the Azores Regional Government; • Project “ACORES-01-0145-FEDER-000072 - AZORES BIOPORTAL – PORBIOTA. Operational Program Azores 2020 (85% ERDF and 15% regional funds); • Portuguese National Funds, through FCT –Fundação para a Ciência e a Tecnologia, within the projects UID/BIA/00329/2013, 2015- 2019, UID/BIA/00329/2020-2023 and UID/BIA/50027/2019 and POCI-01-0145-FEDER-006821; • Portuguese Regional Funds, through DRCT – Direção Regional da Ciência e Tecnologia, within several projects, 2019 and 2020; • CIRN/DB/UAc (Research Centre for Natural Resources, Universidade dos Açores, Departamento de Biologia); • CIIMAR (Interdisciplinary Centre of Marine and Environmental Research, Porto, Portugal).|
|Study Area Description||The Azores archipelago, located in the North Atlantic, roughly at 38°43′49″N 27°19′10″W, comprises nine islands and several islets spread over 500 km in a WNW direction. The climate is temperate oceanic, with persistent winds, regular and abundant rainfall and high levels of relative humidity mainly during winter and autumn (Morton et al. 1998). The islands have a restricted coastal extension due to the lack of a continental shelf, and deep waters occur within a few kilometres offshore. The tidal range is small (<2 m, see Instituto Hidrográfico 1981) and coasts are subjected to swell and surge most of the year. Shore geomorphology alternates between high cliffs and rocky cobble/boulder beaches (Borges 2004). Graciosa Island is the second smallest island of the Azores archipelago. Located in the central group, roughly at 39°0′38″N, 27°59′1″W, about 37 km north of São Jorge and 58 km north-west of Terceira, it has an area of about 62 km2 and a maximum altitude of 402 m at the summit of the Caldeira located at the south-western tip of the island (Neto et al. 2009). With the exception of Serra Branca, bordered by cliffs higher than 200 m, and the area between Lagoa and Barra, where the coastline is of steep cliffs, the remaining coastline of the island is low (below 50 m), with long stretches of cobble beaches interspaced with lava flows (forming irregular extensions of bedrock), boulder areas and the single sandy beach near the small village of Praia. Between Ponta Branca and Carapacho there are several bays, of which the bay of Filipe is the largest in size and easily accessible by land. Rock pools are common on the bedrock shores around the island, creating a shallow subtidal habitat with a rich diversity of marine life (Neto et al. 2009). As on the remaining Azores islands, the intertidal and shallow subtidal rocky-shore communities of Graciosa are dominated by macroalgae (Neto et al. 2005). Thehigh intertidal level communities are characterised by a patchy mosaic of algae (principally Fucus spiralis Linnaeus, Gelidium microdon Kützing and Gymnogongrus spp.) and a few animals (mainly chthamalid barnacles). Lower, the shore is covered by algal turfs (growth forms of either diminutive algae or diminutive forms of larger species that create a dense, compact mat 20-30 mm thick), either monospecific or composed by several species e.g. calcareous algae (e.g. Ellisolandia and Jania), or by soft algae (e.g. Centroceras clavulatum (C.Agardh) Montagne, Chondracanthus and Laurencia). At this level a few limpets may be seen. The erect, corticated macrophytes Elisolandia elongata (J.Ellis & Solander) K.R.Hind & G.W.Saunders, Pterocladiella capillacea (S.G.Gmelin) Santelices & Hommersand and Treptacantha abies-marina (S.G.Gmelin) Kützing are common in the transition zone to the subtidal, which is usually dominated by large foliose species (Neto et al. 2009). Subtidally, algal communities are characterized by associations of two or three frondose macrophytes, predominantly the brown seaweeds, e.g. Dictyota, Halopteris, Zonaria tournefortii (J.V.Lamouroux) Montagne (Neto et al. 2009).|
|Design Description||The algae referred to in this paper were collected during field studies at littoral and sublittoral levels down to approximately 40 m on the island of Graciosa. Each sampling location was visited several times. On each occasion a careful and extensive survey was undertaken to provide a good coverage of the area. Both presence recording and physical collections were made by walking over the shores or by scuba diving. The specimens collected were taken to the laboratory for identification and preservation and the resulting vouchers were deposited at the AZB Herbarium Ruy Telles Palhinha and the Molecular Systematics Laboratory at the Faculty of Sciences and Technology of the University of the Azores.|
The personnel involved in the project:
Intertidal collections were made during low tide by walking over the shore. Subtidal collections were made by scuba diving around the area. Sampling involved specimen collecting and species presence recording. For the former, at each location samples were obtained by scraping one or two specimens of all different species found into labelled bags. The species presence recording data was gathered by registering all species present in the sampled locations visited. Complementary data e.g. shore level (high, mid, low), orientation and type of substrate (bedrock, boulders, cobbles, mixed), habitat (tide pool, open rock, gully, crevice, cave) was also recorded.
|Study Extent||This study covers a relatively large area, approximately 19 km2, encompassing littoral and sublittoral levels down to approximately 40 m around the island of Graciosa.|
|Quality Control||Each sampled taxon was identified by trained taxonomists and involved morphological and anatomical observations of whole specimens by eye, or of slide preparations under the microscope for the diagnostic features described in the literature. In difficult cases specimens were sent to specialists for identification.|
Method step description:
- Specimens were brought back to the laboratory, sorted and studied following standard procedures used in macroalgae identification. Species identification was based on morphological and anatomical characters and reproductive structures. For small and simple thalli, this required the observation of the entire thallus with the naked eye and/or using dissecting and compound microscopes. For larger and more complex algae, investigation of the thallus anatomy required histological preparations (longitudinal and transverse sections) for the observation of cells, reproductive structures and other diagnosing characters. As the Azorean algal flora has representatives from several geographical regions, often causing difficulty in identification, floras and keys for the North Atlantic, Tropical Atlantic and Western Mediterranean were used (e.g. Schmidt 1931, Taylor 1967, 1978, Levring 1974, Dixon & Irvine 1977, Lawson & John 1982, Irvine 1983, Gayral & Cosson 1986, Fletcher 1987, Afonso-Carrillo & Sansón 1989, Burrows 1991, Boudouresque et al. 1992, Cabioc'h et al. 1992, Maggs & Hommersand 1993, Irvine & Chamberlain 1994, Brodie et al. 2007, Lloréns et al. 2012 and Rodríguez-Prieto et al. 2013). For more critical and taxonomically difficult taxa, specimens were taken to the Natural History Museum (London) for comparison with collections there, or sent to specialists. A reference collection was made for all collected specimens by assigning them an herbarium code number and depositing them at the AZB Herbarium Ruy Telles Palhinha and the Molecular Systematics Laboratory, University of Azores. Depending on the species and on planned further research, different types of collections were made, namely (i) liquid collections using 5% buffered formaldehyde seawater and then replacing it by the fixing agent Kew (Bridsen & Forman 1999); (ii) dried collections, either by pressing the algae (most species) as described by Gayral and Cosson (1986), or by letting them air dry (calcareous species); and (iii) silica gel collections for molecular study. Nomenclatural and taxonomic status used here follow Algaebase (Guiry & Guiry, 2020). The database was organized on FileMaker Pro.
|Collection Name||AZB | Marine macroalgae collection of Graciosa Island (Azores) – Expedition GRACIOSA/2004|
|Parent Collection Identifier||AZB Herbarium Ruy Telles Palhinha, Faculty of Sciences and Technology of the University of the Azores|
|Collection Name||AZB | Marine macroalgae collection of Graciosa Island (Azores) – Project PADEL|
|Parent Collection Identifier||AZB Herbarium Ruy Telles Palhinha, Faculty of Sciences and Technology of the University of the Azores.|
|Collection Name||AZB | Marine macroalgae collection of Graciosa Island (Azores) – Occasional sampling|
|Parent Collection Identifier||AZB Herbarium Ruy Telles Palhinha, Faculty of Sciences and Technology of the University of the Azores.|
|Collection Name||Marine macroalgae collection of Graciosa Island (Azores)-Project MACROBIOMOL|
|Parent Collection Identifier||MACROBIOMOL Macroalgae collection, Faculty of Sciences and Technology of the University of the Azores|
|Collection Name||Marine macroalgae collection of Graciosa Island (Azores)-Campaign PIMA/BALA|
|Parent Collection Identifier||PIMA/BALA Macroalgae collection, Faculty of Sciences and Technology of the University of the Azores|
|Collection Name||Marine macroalgae occurrence in Graciosa Island (Azores) – Project PADEL|
|Parent Collection Identifier||Not applicable|
|Specimen preservation methods||Dried and pressed, Dried, Formalin, Other|
- Afonso-Carrillo, J. & Sansón, M., 1989. Clave llustrada para la Determinación de los Macrófitos Marinas Bentónicos de las Islas Canarias [Illustrated key for the determination of the Benthic Marine Macrophytes of the Canary Islands]. Departamento de Biologia Vegetal (Botânica), Universidad de La Laguna, La Laguna. 55 pp.
- Borges, P. J. A., 2004. Ambientes litorais nos grupos Central e Oriental do arquipélago dos Açores - conteúdos e dinâmica de microescala [Coastal environments in the Central and Eastern groups of the Azores archipelago - contents and microscale dynamics]. Tese de Doutoramento em Geologia. Universidade dos Açores, Ponta Delgada.
- Boudouresque, C,-F., Meinesz, A. & Verlaque, M., 1992. Médíterranée. In Boudouresque C-F et al. (Eds.), Guide des Algues des Mers d'Europe, pp: 138-231. Delachaux et Niestlé, Paris.
- Bridsen, D. & Forman, L. (Eds), 1999. The Herbarium Handbook. Third Edition. Kew: The Board of Trustees of the Royal Botanic Gardens, Kew. xii, 334p., ISBN 1-900347-43-1.
- Brodie, J., Maggs, C., John, D. M. (Eds.), 2007. The green seaweeds of Britain and Ireland. British Phycological Society, XII+242 pp. Dunmurry, Northern Ireland.
- Burrows, E. M., 1991. Seaweeds of the British lsles. Vol. 2. Chlorophyta. Natural History Museum, London. XII + 238 pp.
- Cabioc'h, J., Floc'h, J. –Y. & Le Toquin, A., 1992. Manche et Atlantique. ln C.-F. Boudouresque, et al. (Eds.), Cuide des Algues des Mers d'Europe, pp: 30-136. Delachaux et Niestlé, Paris.
- Dixon, S. P. & Irvine, M. L., 1977. Seaweeds of the British Isles. Vol. I Rhodophyta. Part 1 Introduction, Nemaliales, Gigartinales. XI+252p. British Museum (Natural History) London.
- Fletcher, R. L., 1987. Seaweeds of the British Isles. Vol. III. Fucophyceae (Phaeophyceae). Part 1. X+359p. British Museum (Natural History) London.
- Freitas, R, Romeiras M, Silva L, Cordeiro R, Madeira P, González JA, Wirtz P, Falcón JM, Brito A, Floeter SR, Afonso P, Porteiro F, Viera-Rodríguez MA, Neto AI, Haroun R, Farminhão JNM, Rebelo AC, Baptista L, Melo CS, Martínez A, Núñez J, Berning B, Johnson ME Ávila SP, 2019. Restructuring of the ‘Macaronesia’ biogeographic unit: A marine multi-taxon biogeographical approach. Scientific Reports, 9, 15792 DOI:10.1038/s41598-019-51786-6
- Gayral, P. & Cosson, J., 1986. Connaitre et reconnaitre les algues marines [Know and recognize seaweed]. 220p. Ouest France
- Guiry, M. D. & Guiry, G. M., 2020. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. https://www.algaebase.org; searched on May, 26.
- Hortal, J., de Bello, F., Diniz-Filho, J. A. F., Lewinsohn, T. M., Lobo, J. M. & Ladle, R. J., 2015. Seven shortfalls that beset large-scale knowledge of biodiversity. Annual Review of Ecology, Evolution, and Systematics, 46, 523-549.
- Instituto Hidrográfico, 1981. Roteiro do Arquipélago dos Açores. PUB. (N) -lli-128-SN, Lisboa.
- Irvine, M. L., 1983. Seaweeds of the British Isles. Vol. I Rhodophyta. Part 2 A Cryptonemiales (sensu stricto), Palmariales, Rhodymeniales. XII+115p. British Museum (Natural History) London.
- Irvine, M. L. & Chamberlain, Y. M., 1994. Seaweeds of the British Isles. Vol. 1. Rhodophyta. Part 2B. Corallinales, Hildenbrandiales. Natural History Museum, London. VII + 276 pp.
- Lawson, G. W. & John, D. M., 1982. The marine algae and coastal environment of Tropical West Africa. 455p. Beihefte zur Nova Hedwigia, J. CRAMER, Vaduz.
- Levring, T., 1974. The marine algae of the archipelago of Madeira. Boletim do Museu Municipal do Funchal, 28 (125): 5-111.
- Lloréns, J. L. P., Cabrero, I. H., Lacida, R. B., González, G. P., Murillo, F. G. B. & Oñate, J. J. V., 2012. Flora marina del litoral gaditano. Biologia, ecologia, usos y guía de identificacíon. 368 p. mCN Monografias de Ciencias de la Naturaleza. Servicio de Publicaciones de la Universidad de Cadiz, Cadiz.
- Maggs, C. A. & Hommersand, M. H., 1993. Seaweeds of the British Isles. Vol1. Rhodophyta. Part 3A. Ceramiales. Natural History Museum, London. xv + 444 pp.
- Morton, B., Britton, J. C., Martins, A. M. F., 1998. Coastal Ecology of the Azores. Sociedade Afonso Chaves, Ponta Delgada. 249pp.
- Neto, A. I., Tittley, I. & Raposeiro, P., 2005. Flora Marinha do Litoral dos Açores [Rocky Shore Marine Flora of the Azores]. 156pp., Secretaria Regional do Ambiente e do Mar, Açores, ISBN 972 99884 0 4. http://hdl.handle.net/10400.3/1677
- Neto, A. I., Wallenstein, F. M., Álvaro, N. V. & Azevedo, J. M. N., 2009. Guias Costeiros dos Açores: Ilha Graciosa [Coastal Guides of the Azores: Graciosa Island]. Secretaria Regional do Ambiente e do Mar e Câmara Municipal de Santa Cruz da Graciosa, Açores. ISBN 978-989-95723-5-5 | 978-972-96962-4-4
- Rodríguez-Prieto, C., Ballesteros, E., Boisset, F. & Afonso-Carrillo, J., 2013. Guía de las macroalgas y fanerógamas marinas del Mediterráneo Occidental. 656 p. Ed. Omega, S.A., Barcelona.
- Schmidt, O. C., 1931. Die marine vegetation der Azoren in ihren Grundzügen dargestellt. Bibliotheca Botanica, 24(102): IX+116p., 10 Tafl.
- Taylor, W. R., 1967. Marine algae of the northeastern coasts of North America. VIII+509p. The University of Michigan Press.
- Taylor, W. R., 1978. Marine algae of the eastern tropical and subtropical coasts of the Americas. XXI+870p. The University of Michigan Press.
- Tittley I & Neto AI, 2005. The Marine Algal (Seaweed) Flora of the Azores: additions and amendments. Botanica Marina, 48: 248-255. DOI 10.1515/BOT.2005.030
- Wallenstein, F. M., Neto, A. I., Álvaro, N. V., Tittley, I. & Azevedo, J. M. N., 2009. Guia para Definição de Biótopos Costeiros em Ilhas Oceânicas [Coastal Biotope Definition Manual for Oceanic Islands], Secretaria Regional do Ambiente e do Mar, ISBN 978-972-99884-9-3. http://hdl.handle.net/10400.3/1687
Additional information on this study may also be requested to the first author.