Corresponding author: Catarina Ritter (
Academic editor: Saúl Blanco
Here, we present the data obtained from the samples collected in a field campaign during the spring of 2015 which aims for a better understanding of the diversity and distribution patterns of freshwater diatoms in Madeira Island. Following European and Portuguese standards and recommendations for routine diatom sampling and analysis, we collected samples in 40 sites, distributed in 27 permanent streams and identified the diatom species present, using general diatom floras and studies in Portuguese freshwater diatoms.
Little is known about the diversity and distribution of freshwater diatom assemblages from Madeira Archipelago. This study reports a survey in 40 sites in Madeira Island distributed in 27 permanent streams. A total of 965 diatom (
Diatoms (
Despite their great importance, current knowledge about the freshwater diatoms on insular streams of Madeira Archipelago is limited in comparison with freshwater macroinvertebrates (
Here, we provide a detailed dataset that contains freshwater diatom occurrences collected during a field campaign on Madeira Island, increasing the knowledge on the epilithic diatom inhabiting permanent streams in Madeira Island. Our purpose is to release this valuable dataset, since no similar datasets have been previously published for Madeira Archipelago and it constitutes a relevant tool of comparison for aquatic ecologists, for example, biogeographic patterns, climate change or other studies on oceanic islands.
Diatom diversity and distribution in Madeira Island streams (Portugal)
Collections were undertaken and occurrence data recorded during the spring of 2015 in Madeira Island. The collectors were Pedro Raposeiro and Vitor Gonçalves. Identifications were made by Catarina Ritter and supervised by Vitor Gonçalves.
The Madeira Archipelago is an oceanic archipelago located in the North Atlantic between latitudes 32°24' and 33°07'N and longitudes 16°16' and 17°16'W (Fig.
Madeira Island comprises approximately 126 catchments and 200 streams presenting a typical radial drainage pattern common in oceanic islands (
Epilithic freshwater diatoms (
In the spring of 2015, epilithic biofilm samples were collected in 40 sites (MAD01 – MAD40) from 27 permanent streams in Madeira Island (Table
Diatom morphometric features were determined by photomicrography (Leica DFC495) with the aid of image analysis software (LAS version 3.8.0). Diatom identification was based on reference diatom floras (e.g.
The data have been published as a Darwin Core Archive (DwC-A), which is a standardised format for sharing biodiversity data as a set of one or more data tables. The core data table contains 965 occurrences with 130 records (
Madeira Island, Madeira Archipelago, Macaronesia, Portugal.
32.6228N and 32.8815N Latitude; -17.2739W and -16.6487W Longitude.
All diatoms were identified to genus or species level. In total, 130 taxa were identified belonging to five subclasses, 17 orders, 27 families and 44 genera distributed in the subphylums
Rank | Scientific Name | Common Name |
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phylum |
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Diatom |
Open Data Commons Attribution License
This work is licensed under a Creative Commons Attribution (CC-BY) 4.0 License.
Diatom distribution in Madeira Island streams (Portugal)
1
Diatom distribution in Madeira Island streams (Portugal)
Darwin Core Archive
1.2
This paper presents data from freshwater diatoms surveys developed in Madeira Island in 2015. The dataset has been published as a Darwin Core Archive (DwC-A), which is a standardised format for sharing biodiversity data as a set of one or more data tables. The core data table contains 40 events (eventID), 965 occurrences (occurrenceID) with 130 taxa (taxonID). The number of records in the data table is illustrated in the IPT link. This IPT archives the data and thus serves as the data repository. The data and resource metadata are available for downloading in the downloads section.
Column label | Column description |
---|---|
scientificNameAuthorship | The authorship information for the scientificName. |
type | The nature of the resource. |
basisofRecord | The specific nature of the data record. |
occurrenceID | Identifier of the record, coded as a global unique identifier. |
eventID | Identifier of the event, unique for the dataset. |
eventDate | Time interval when the event occurred. |
continent | Continent of the sampling site. |
waterBody | Water body of the sampling site. |
islandGroup | Island group of the sampling site. |
island | Island from the Island Group of the sampling site. |
country | Country of the sampling site. |
countryCode | Code of the country where the event occurred. |
municipality | Name of the municipality where the event occurred. |
locality | Name of the locality where the event occurred. |
decimalLatitude | The geographic latitude of the sampling site. |
decimalLongitude | The geographic longitude of the sampling site. |
geodeticDatum | The spatial reference system upon which the geographic coordinates are based. |
taxonID | The identifier for the set of taxon information (data associated with the Taxon class). Specific identifier to the dataset. |
scientificName | The name with authorship applied on the first identification of the specimen. |
acceptedNameUsage | The specimen accepted name, with authorship. |
kingdom | Kingdom name. |
phylum | Phylum name. |
class | Class name. |
order | Order name. |
family | Family name. |
genus | Genus name. |
specificEpithet | The name of the first or species epithet of the scientificName. |
infraspecificEpithet | The name of the lowest or terminal infraspecific epithet of the scientificName, excluding any rank designation. |
taxonRank | The taxonomic rank of the most specific name in the scientificName. |
coordinateUncertaintyInMetres | The indicator for the accuracy of the coordinate location in metres, described as the radius of a circle around the stated point location. |
This study presents 965 diatom (
The subphylum
The families with the highest number of occurrences were
The genera with the highest number of occurrences were
A total of 45 diatom taxa occurring at only one sampling site were considered rare. These include benthic species, such as
Another 32 diatom taxa were considered occasional, occurring in two to five sampling sites. These included benthic species, such as
The mean number of taxa per sample was 24.1 ± 1.1 SE taxa. MAD40, MAD14, MAD26 and MAD23 were the samples with the highest number of taxa, 49, 38, 34 and 32, respectively. The samples with the lowest number of taxa were MAD20, MAD19 and MAD09 with 11, 14 and 15 taxa, respectively.
The two diatom endemisms, described previously in Madeira Island (Lange-Bertalot, 1993),
In this survey, 60 records were new, not only to Madeira Island, but also to the Madeira Archipelago (Table
The diatom diversity (130 taxa belonging to 44 genera) displayed by Madeira Island in the 27 permanent streams in this study is due to the habitat complexity (including water quality, habitat structure and climate), as well as large scale-effects stemming from the Islands’ isolation and geographical location as was found on other oceanic islands (
Diatom diversity from Madeira Island is relatively low when compared to other oceanic islands and continental regions (e.g.
Nonetheless, when comparing archipelagos in the Macaronesia Region, 201 diatom taxa were recorded in 316 samples from 14 permanent Azorean streams (
Comparisons to other regions in the world reveal how diatom diversity in Madeira Island is “poor”. For instance, in a tropic region (Sub-Saharan Africa), the number of diatom taxa identified in 67 sites in Kenya was significantly greater (297 taxa) than the number of taxa recorded in Madeira Island (
The low diversity of freshwater biota has already been reported to the Madeira Archipelago (
This insular oceanic ecosystem should offer some degree of isolation from continental floras, but the special conditions that promote speciation on islands are not present, for example, extreme water quality or geological age and activity (
The Macaronesia Region should register more endemisms for many groups as do other regions (e.g. Antarctic Region,
Considering the significant differences between the islands of Madeira Archipelago, such as geological ages, volcanic composition, climate patterns and distribution, land uses, types of forest and orography, we expect higher diatom species richness and exclusive taxa from these islands (Porto Santo, Desertas, Selvagens). Furthermore, increasing the sampling effort in Madeira Island, for instance, by sampling other streams and/or other sites in the Laurissilva forest, may result in the identification of other diatom taxa. Additionally, higher time replication and larger datasets are required to better understand distribution patterns and large-scale spatial patterns of species dispersal. According to
The factors controlling taxa richness, as well as the regional endemic taxa, remain unclear as there is no convincing link with the simplified habitat features recorded during the study and more research is needed. Relationships are probably multivariate in nature and include site history, unmeasured micro-habitat availability and climate (
The results of this study provide baseline knowledge on the current distribution of freshwater diatoms on Madeira Island streams, revealing a distinct, but taxonomically simple diatom flora, typical from oceanic island ecosystems (
This work was funded by national funds through FCT – Foundation for Science and Technology under the PTDC/CTA-AMB/28511/2017 and DL57/2016/ ICETA/EEC2018/25. The field surveys comply with the current laws of Portugal. Thanks are also extended to the reviewers for their very useful comments on earlier versions of this manuscript.
CR, PMR, VG conceived the study and PMR and VG carried out the sampling campaign in Madeira Island. CR prepared and identified the epilithic diatoms and VG supervised. CR wrote the paper with inputs from all authors. All authors agree with the final version of the paper.
Geographical location of the study stream sites.
Sampling site representing the natural land-use. Located at Ribeira Primeira, Santo António da Serra, Machico (MAD18).
Sampling site representing the agricultural land-use. Located at Ribeira de São Jorge, Santana (MAD37).
Sampling site representing an urban land-use. Located at Ribeira da Janela, Porto Moniz (MAD21).
Collecting epilithic diatoms from stones with a toothbrush at each sampling site.
Sampling codes and location of the forty studied stream sites on Madeira Island.
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MAD01 | Ribeira dos Socorridos | Câmara de Lobos | 28/04/2015 |
|
85 |
MAD02 | Ribeira Brava | Ribeira brava | 28/04/2015 |
|
409 |
MAD03 | Ribeira da Vargem | São Vicente | 28/04/2015 |
|
450 |
MAD04 | Ribeira de São Vicente | São Vicente | 28/04/2015 |
|
325 |
MAD05 | Ribeira Grande | São Vicente | 28/04/2015 |
|
311 |
MAD06 | Ribeira Grande | São Vicente | 28/04/2015 |
|
60 |
MAD07 | Ribeira Brava | São Vicente | 28/04/2015 |
|
903 |
MAD08 | Ribeira Brava | São Vicente | 28/04/2015 |
|
833 |
MAD09 | Ribeira dos Socorridos | Câmara de Lobos | 29/04/2015 |
|
826 |
MAD10 | Ribeira da Gomeira | Câmara de Lobos | 29/04/2015 |
|
725 |
MAD11 | Corgo da Ribeira de Anéis | Câmara de Lobos | 29/04/2015 |
|
780 |
MAD12 | Ribeira do Cidrão | Câmara de Lobos | 29/04/2015 |
|
597 |
MAD13 | Ribeira do Machico | Machico | 29/04/2015 |
|
10 |
MAD14 | Ribeira do Juncal | Machico | 29/04/2015 |
|
36 |
MAD15 | Ribeira do Juncal | Machico | 29/04/2015 |
|
187 |
MAD16 | Ribeira do Faial | Machico | 29/04/2015 |
|
560 |
MAD17 | Ribeira do Machico | Machico | 29/04/2015 |
|
624 |
MAD18 | Ribeira Primeira | Machico | 29/04/2015 |
|
791 |
MAD19 | Ribeira do Machico | Machico | 29/04/2015 |
|
877 |
MAD20 | Ribeira de Santa Cruz | Santa Cruz | 29/04/2015 |
|
7 |
MAD21 | Ribeira da Janela | Porto Moniz | 30/04/2015 |
|
81 |
MAD22 | Ribeira do Alecrim | Porto Moniz | 30/04/2015 |
|
1391 |
MAD23 | Ribeira da Janela | Porto Moniz | 30/04/2015 |
|
1089 |
MAD24 | Ribeira da Janela | Porto Moniz | 30/04/2015 |
|
1041 |
MAD25 | Ribeira dos Cedros | Porto Moniz | 30/04/2015 |
|
899 |
MAD26 | Ribeira da Janela | Porto Moniz | 30/04/2015 |
|
1003 |
MAD27 | Ribeira da Janela | Porto Moniz | 30/04/2015 |
|
1271 |
MAD28 | Ribeira do Alecrim | Porto Moniz | 30/04/2015 |
|
1182 |
MAD29 | Ribeira Frio | Santana | 01/05/2015 |
|
846 |
MAD30 | Córrego do Arrochete | Santana | 01/05/2015 |
|
637 |
MAD31 | Ribeira da Metade | Santana | 01/05/2015 |
|
686 |
MAD32 | Ribeira das Lajes | Santana | 01/05/2015 |
|
23 |
MAD33 | Ribeira de São Roque do Faial | Santana | 01/05/2015 |
|
42 |
MAD34 | Ribeira Seca | Santana | 01/05/2015 |
|
103 |
MAD35 | Ribeira de São Jorge | Santana | 01/05/2015 |
|
121 |
MAD36 | Ribeira dos Arcos | Santana | 01/05/2015 |
|
517 |
MAD37 | Ribeira de São Jorge | Santana | 01/05/2015 |
|
21 |
MAD38 | Ribeira de Santa Luzia | Funchal | 02/05/2015 |
|
25 |
MAD39 | Ribeira da Fonte do Bugio | Calheta | 02/05/2015 |
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22 |
MAD40 | Ribeira da Ponta do Sol | Ponta do Sol | 02/05/2015 |
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85 |
Main taxonomic figures.
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1 | 1 | 2 | 1 | 1 | |
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1 | 2 | 22 | 21 | 10 | 1 |
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2 | 6 | 18 | 16 | 9 | |
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3 | 7 | 18 | 18 | 8 | |
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1 | 1 | 4 | 3 | 3 | |
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1 | 1 | 1 | 1 | ||
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2 | 3 | 14 | 14 | 9 | |
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1 | 1 | 1 | 1 | ||
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1 | 2 | 3 | 2 | 3 | |
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2 | 2 | 2 | 2 | ||
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7 | 12 | 2 | 31 | 13 | 1 |
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1 | 1 | 31 | 2 | ||
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1 | 1 | 2 | 2 | 2 | |
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1 | 1 | 1 | 1 | 1 | |
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1 | 2 | 3 | 3 | ||
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1 | 1 | 4 | 3 | 1 |
New records for Madeira Archipelago and respective sampling sites.
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MAD40 | |
MAD40 | ||||
MAD25 | ||||
MAD28 | ||||
MAD14 | ||||
MAD14 | ||||
MAD06; MAD11; MAD12; MAD13; MAD14; MAD31; MAD34; MAD36; MAD37; MAD40 | ||||
MAD11; MAD12; MAD14; MAD16; MAD25; MAD34; MAD37; MAD38 | ||||
MAD08; MAD09; MAD11; MAD21; MAD38 | ||||
MAD25; MAD26 | ||||
MAD39 | ||||
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|
MAD22 | ||
MAD30 | ||||
MAD32 | ||||
MAD01; MAD33; MAD36 | ||||
MAD09; MAD10; MAD12; MAD21 | ||||
MAD19 | ||||
MAD40 | ||||
MAD01; MAD34; MAD36; MAD40 | ||||
MAD17; MAD19; MAD30; MAD35 | ||||
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MAD14; MAD15; MAD21; MAD22; MAD23; MAD36 | ||
MAD21 | ||||
MAD14 | ||||
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MAD23 | |||
MAD40 | ||||
MAD07; MAD08; MAD11; MAD14; MAD15; MAD23; MAD25; MAD26; MAD27; MAD31 | ||||
MAD23; MAD40 | ||||
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MAD14; MAD15; MAD39 | |||
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MAD22 | ||
MAD08; MAD18; MAD19; MAD24; MAD27 | ||||
MAD31 | ||||
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MAD26; MAD35; MAD36; MAD37; MAD40 | ||
MAD03; MAD21; MAD23; MAD26; MAD36; MAD40 | ||||
MAD16; MAD25 | ||||
MAD06; MAD12; MAD31; MAD32; MAD34; MAD38 | ||||
MAD05; MAD20; MAD22; MAD23; MAD28; MAD30; MAD35 | ||||
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MAD08 | |||
MAD30 | ||||
MAD26 | ||||
MAD23 | ||||
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MAD40 | ||
MAD40 | ||||
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MAD27 | ||
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MAD19 | |||
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MAD34 | |||
MAD02; MAD14 | ||||
MAD13; MAD14; MAD40 | ||||
MAD40 | ||||
MAD26; MAD29 | ||||
MAD28; MAD29; MAD40 | ||||
MAD07; MAD08; MAD14; MAD25; MAD26, MAD27, MAD28; MAD33; MAD34; MAD37; MAD39 | ||||
MAD14; MAD 25; MAD27; MAD34 | ||||
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MAD02; MAD04; MAD07; MAD08; MAD12; MAD13; MAD15; MAD16; MAD17; MAD18; MAD21; MAD22; MAD23; MAD29; MAD30; MAD33; MAD34; MAD36; MAD38; MAD39; MAD40 | |||
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MAD11; MAD12; MAD30 | |||
MAD01; MAD02; MAD04; MAD09; MAD10; MAD12; MAD13; MAD14; MAD15; MAD16; MAD17; MAD18; MAD20; MAD21; MAD33; MAD34; MAD35; MAD38; MAD40 | ||||
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MAD40 | ||
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MAD31 | ||
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MAD04 | |
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MAD14 | |
MAD40 |