Active involvement of volunteers has greatly assisted inventorying and monitoring of marine biodiversity, over the last decade (Thiel et al. 2014). Notable Mediterranean examples of Citizen Science (CS) initiatives focusing on marine biodiversity concern the study and monitoring of vulnerable species (Goffredo et al. 2004, Bramanti et al. 2011), gelatinous plankton aggregations (Boero et al. 2013, Boero et al. 2009), fish assemblages (Arvanitidis et al. 2011, Azzurro et al. 2012, Bulleri and Benedetti-Cecchi 2014), non-indigenous species (Zenetos et al. 2013, Bodilis et al. 2013), or a combination of several diversity features (e.g. Seawatchers). Although a plethora of CS projects deal with tropical coral reefs (e.g. Hodgson 2001, Marshall et al. 2012, Branchini et al. 2014) at a global scale, none has focused on their Mediterranean counterparts.

Mediterranean coralline reefs, widely known as "coralligenous" (from the french term "coralligène", sensu Marion 1883), are bioherms built by calcifying rhodophytes on hard substrates under dim-light conditions. They are considered hotspots of biodiversity, harbouring rich assemblages and valuable biological resources (Ballesteros 2006). Coralligenous beds and their assemblages are extremely popular among SCUBA divers due to their complex structure, conspicuous biological wealth and high aesthetic value. Nevertheless, data on their distribution, structure and conservation status is lacking for several Mediterranean areas (e.g. southern and eastern Mediterranean regions) while they are vulnerable to an increasing number of threats (Giakoumi et al. 2013, Martin et al. 2014, Gatti et al. 2015).

The CIGESMED SeasEra project aims to enhance understanding on the links between natural and anthropogenic pressures and ecosystem functioning to define and maintain the “Good Environmental Status” (GES) of the Mediterranean Sea, through the integrated study of coralligenous assemblages. In the framework of CIGEDMED SeasEra project, a specialized CS initiative was launched aiming to engage enthusiast divers in the study of this Mediterranean habitat in order to obtain information regarding its spatial distribution, enable a primary characterization of the basic structure of its assemblages, and monitor potential pressures and threats to the habitat. The initial development of this pilot CS project was based on previous experience of the IMBBC (Institute of Marine Biology, Biotechnology and Aquaculture, HCMR) research group and CIGESMED partners on citizen science pilots design and implementation, as well as on the human, hardware and software resources of the LifeWatchGreece Research Infrastructure, a landmark in the European Strategy Forum on Research Infrastructures (ESFRI) roadmap. This paper aims to describe the background, basic principles and structure of the specialized CS initiative, along with the developed infrastructure, tools and guidelines that will support the ongoing collection of data on a Mediterranean scale.

Preparatory phase and methodological concept

Identifying the profile of citizen scientists

Website development and mobile applications

Field trials and preliminary data gathering

The developed CS methodological protocol and CIGESMED for divers website (http://cs.cigesmed.eu/) comprise:

• An educational module with simplified information regarding coralligenous assemblages, in order to ensure a basic understanding of these habitats by the diving community, answers to frequently asked questions that were identified during the field trials, and detailed guidelines for in situ data collection in five languages; English (Suppl. material 1), French (Suppl. material 2), Greek (Suppl. material 3), Italian (Suppl. material 4), and Turkish (Suppl. material 5).
• A multilingual data submission infrastructure, using an online web platform, where one can readily download the data-recording dive slates and subsequently upload the recorded information after each dive; the printable dive slates include visual guides and fill-in forms in English (Suppl. material 6), French (Suppl. material 7), Greek (Suppl. material 8), Italian (Suppl. material 9), and Turkish (Suppl. material 10) while the web version is also available in Spanish.

The website requires registration from the user in order to be able to submit, view and review data. During the initial registration process, users are requested to submit basic personal data (e.g. name, country of residence, affiliation) and information on their diving profile (i.e. diving experience and certification level), dive computer brand and type (for standardizing temperature data records), past experience from any other CS projects, area of taxonomic interest in cases of professional scientists and enthusiast naturalists, and dive centre (Fig. 1). Users are also able to choose among two data entry form options: (a) Standard taxonomic, that is ranking taxa in a standard phylogenetic order for educational/scientific reasons, or (b) a guided version, following the arrangement on the printed slate version, where different taxa are ranked in a way optimized to facilitate reporting in situ, according to experience gained from the field trials.

Figure 1.  

User account registration form of CIGESMED for divers website.

The main data submission infrastructure (dive slate and web version) provides fields for reporting information relevant to the characterization of the site and the assessment of its coralligenous assemblages, organized in two sections: (a) basic data and parameters, and (b) ecological observations (Fig. 2). In the web version it is clearly stated that the information fields requested within those two sections are optional, i.e. at each recording event the participant is free to submit whichever data he/she was able to collect during the dive or he/she is willing to share. There are three compulsory fields, namely "Date of observation", "Geographic Reference" and "Observation depth (m)", marked with an asterisk (*). In several cases, images and explanatory texts are provided for certain fields (e.g. Thermocline’s Depth: At what depth did you feel a sharp decrease of temperature?) and their observation ranks. Online data submission is aided with tick boxes, selections from drop-down menus, free text fields, and an interactive map (Leaflet.js and Google Maps).

Figure 2.  

Observation form in the data submission platform of the CIGESMED for divers website.

Basic data and parameters

Ecological observations: reporting biodiversity and threats

This section of the CS platform focuses on: (a) the presence and relative abundance of typical conspicuous species of coralligenous assemblages and (b) the recording of pressures and imminent threats. A total of 23 taxa belonging to 7 taxonomic groups were included in the CS protocol (Table 2). The list is restricted to the minimum number of species possible, so as not to overwhelm citizen scientists with a large amount of information. The scope of this taxon list was not to be as comprehensive as possible but rather to include certain taxa that are characteristic of the various coralligenous facies, as well as a number of rare, protected and commercial species the reporting of which is scientifically interesting. Confirmation of the presence of coralligenous assemblages and their rough characterization were the main priorities considered. The taxa comprising the list are conspicuous and properly selected to assure: (a) easy identification underwater, (b) common presence in approachable coralligenous formations, (c) indication of a true coralligenous assemblage, and (d) potential presence in different regions of the Mediterranean basin, taking into account biogeographical heterogeneity. Therefore, species that may be characteristic of coralligenous bioherms but are difficult to spot or identify in situ by amateurs were omitted in favour of more conspicuous ones. On the other hand, the inclusion of a free-text field for reporting organisms not included in the basic list, allows more advanced users to upload additional records according to their best knowledge level. Information on the appropriate underwater recording of species, as well as their importance for the marine ecosystem are presented in the multilingual guidelines in a comprehensive manner.

Table 2.

Download as

CSV

XLSX

List of coralligenous biota examined in the current CS initiative (* protected species).

RHODOPHYTA

Calcareous red algae (e.g. Lithophyllum spp. and Mesophyllum spp.)

Peyssonnelia spp.

PORIFERA

Agelas oroides

Axinella spp. *

Cliona spp.

ANTHOZOA

Eunicella cavolini *

Eunicella singularis*

Paramuricea clavata *

Leptogorgia sarmentosa

Savalia savaglia*

Scleractinians (e.g. Leptopsammia pruvoti, Polycyanthus muellerae, Madracis pharensis, Hoplangia durotrix, and Phyllangia americana mouchezii) *

Corallium rubrum *

CRUSTACEA

Homarus gammarus

Palinurus elephas

Scyllarides latus *

BRYOZOA

Myriapora truncata

Other erect bryozoans (e.g. Adeonella spp., Smittina spp., Pentapora fascialis, Reteporella spp.)

ECHINODERMATA

Centrostephanus longispinus *

Other sea urchins (e.g. Arbacia lixula, Echinus melo, Paracentrotus lividus, Sphaerechinus granularis)

PISCES

Anthias anthias

Epinephelus marginatus *

Scorpaena spp.

Shark egg cases (e.g. Scyliorhinus canicula)

Typical species/taxa are presented in a list, accompanied by professional grade in situ photographs of the organisms from different Mediterranean areas, and linked to galleries providing additional photographic material (Fig. 3), covering as many viewing angles, morphologic and colour variations of the taxa as possible (ca. 100 images were assembled for this purpose). Semi-quantitative assessment of abundance is requested to be provided in size classes (N/A: Not available, Absent, Scarce, Abundant, Very abundant). Furthermore, the option of uploading photographs (i.e. Add Images) is available to the users and is encouraged as the recommended practice, since it provides the means to validate the diver’s observations. These photos are automatically added to the website’s Gallery following curation by the CS research team to avoid misidentifications.

Figure 3.  

List of typical species of Mediterranean coralligenous assemblages on the CIGESMED for divers website, linked to galleries with representative photographs. Users have the ability to select pre-defined abundance classes and upload their own images for every listed taxon.

A list of 10 types of pressures and threats commonly affecting coralligenous assemblages was included to the protocol (Table 3, Fig. 4), providing a basis for their reporting. For each category, citizen scientists have the option to quantify its intensity using 3 observation ranks (i.e. absent, limited, and extended). As is the case for species reporting, users also have the possibility to report other threat categories (i.e. Other Pressures & Threats) and any other type of observations (i.e. Other observations) in the respective free text fields, in order to allow commenting or providing any additional information.

Table 3.

Download as

CSV

XLSX

List of pressures and threats included in the protocol

Non-indigenous species: Caulerpa cylindracea

Non-indigenous species: Asparagopsis spp.

Mucilaginous aggregations

Organism necrosis and mortality events

Sedimentation on coralligenous biota

Diver recklessness

Fishing gear

Litter

Anchoring

Urban waste sources nearby

Other pressures & threats (free text)

Figure 4.  

Reporting the intensity of pressures and threats on the CIGESMED for divers website.

Data sharing policy and activities

All currently available data reports of coralligenous formations, their conspicuous species and threats are visibly marked on the accumulative map of the CS website (Fig. 5). Submitted data are open to public view and pass through a quality control process by the CIGESMED CS team before being reposited to global biodiversity databases (e.g. GBIF). As the website is social media-friendly, it provides out-of-the-box widgets allowing users to easily share observations or pages through popular social media (e.g. Twitter, Facebook, and LinkedIn).

Figure 5.  

Accumulative map of uploaded observations for Mediterranean coralligenous assemblages on the CIGESMED for divers website.

Enhancing motivation of participants

Smartphone applications

The "Citizen Science" sub-application of the LifeWatchGreece mobile app aggregates data from different CS initiatives in order to support a simple and quick view process, assisting sharing of the obtained information. It is available for Android platforms (Mobile/Tablet) and receives data in JSON format from CIGESMED for divers website in real time. The application showcases a simplified version of the observations submitted to the "CIGESMED for divers" website on a map. Users are given the option to select and view details for each observation, such as the list of reported species (Fig. 6). By selecting a species, users can view its distribution, based on the registered data, as well as taxonomic and ecological information from global biodiversity databases like GBIF and FishBase (Fig. 7). Furthermore, species records are connected to the Micro-CT_vlabsub-application of LifeWatchGreece mobile app where users can explore relevant Micro-CT datasets (i.e. series of images using X-Ray micro-computed tomography) through images, videos and 3D models that can be virtually manipulated, dissected and rotated using online tools (see Keklikoglou et al. 2016, this special collection).

Figure 6.  

Interface of the smartphone application showcasing information regarding Mediterranean coralligenous assemblages and species obtained from CIGESMED for divers website. This is a “Citizen Science” mobile sub-application of the LifeWatchGreece infrastructure.

Figure 7.  

Interface of the smartphone application displaying the exchange of information between different applications of LifeWatchGreece infrastructure and global biodiversity databases.

The engagement of citizens in marine research is particularly important, since professional scientific activities are often restricted by available financial and human resources (Thiel et al. 2014). Moreover, research projects often follow a confined implementation time schedule, after which research focus shifts to different subjects. The present CS initiative aims to maximize the geographical and temporal capacity of CIGESMED project. Although the core research activities of CIGESMED are localized in France, Greece and Turkey, the flexible and multilingual character of the CS protocol and website infrastructure enable their implementation on a Pan-Mediterranean scale. Our long-term goal is to establish a user-friendly and scientifically meaningful tool for the mapping, ecological status assessment and monitoring of coralligenous assemblages across the Mediterranean.

The objectives of this CS initiative extend beyond single-point data collection by providing a way to monitor coralligenous assemblages and assess potential degradation through the creation of long-term data series in sites receiving multiple visits (e.g. Marine Protected Areas). The inclusion in the protocol of several rare, protected, and commercial species (e.g. the over-exploited red coral), could further assist in their monitoring and conservation. This is particularly important in countries where research funds dedicated to environmental assessment and monitoring of the marine environment are low or non-existent; under such circumstances the contribution of skilled citizen scientists could critically enable the persistent collection of qualitative or semi-quantitative data (Bramanti et al. 2011).

The increasingly important role that active volunteers can play in reporting of the presence and spread of marine allochthonous species has been recently pointed out (Scyphers et al. 2014, Zenetos et al. 2013), along with the necessity for visible centralized data submission and dissemination platforms that can drive citizen participation. In this context, an array of established citizen-monitored sites can prove valuable to swift alien biodiversity records, especially if their online infrastructure is directly linked to relevant data aggregation channels (e.g. ELNAIS).

Citizen-science approaches are generally acknowledged as a main pathway to assist the progress towards the upscaling of ecological data to the global level (Edgar et al. 2016). In this context, LifeWatchGreece research infrastructure (ESFRI) provides the means, expertise and the continuous technical support for the maintenance and development of the electronic platform behind the pilot CIGESMED for divers CS project for the coralligenous habitats in the Mediterranean. It also provides the electronic infrastructure needed for: (a) the data management in order to be harvested by the international aggregators, such as OBIS and GBIF; (b) the appropriate electronic infrastructure in order to analyze the data and interpret the results, in the form of the virtual laboratory RvLab (Varsos et al. 2016, this special collection).

Sharing data is one of the main objectives of CIGESMED. However, data assembled by non-experts should go through quality control before being used in scientific analyses or reposited to global biodiversity databases (Arvanitidis et al. 2011, Thiel et al. 2014). The list of organisms included in the present CS protocol include conspicuous species that are relatively easy to correctly identify. These include species that serve as ecosystem engineers and define coralligenous assemblages, such as coralline algae, sponges and gorgonians, as well as motile fauna that is also typical of this habitat type (e.g. Anthias anthias). The provision of detailed guidelines, easy-to-follow directions, high quality photos and simplified dive-slate versions of the CS protocol offer essential tools for data standardization and minimization of observer bias. Additionally, the online data submission platform encourages divers to upload their photos for each species record, thus facilitating quality control. Each observation is associated to the user’s name, giving the opportunity to the CS research team to access the profile features of the diver (e.g. participation in other CS projects, diving experience, taxonomic expertise for scientific divers and naturalists) or even to contact him/her directly in exceptional cases (e.g. outstanding records, reporting of severe habitat degradation). For this reason, we have established groups of "country managers" among the involved researchers, acting as focal points responsible for providing support to users, managing and evaluating observations from different geographic regions, performing quality control and contacting divers in their language when needed.

Following screening and quality control, the data collected by the CIGESMED for divers project will be further used to: (a) calculate the values of indices for the assessment of the "good environmental status" (GES) of the habitat, as required by the Marine Strategy Framework Directive (MSFD). For this purpose, only indices requiring a minimum of information will be used, such as those proposed under the Descriptor 6 of the MSFD (sea-floor integrity) (Rice et al. 2012); (b) the calculation of the values of the Essential Biodiversity Variables (EBVs) (Pereira et al. 2013) that can be applied to coralligenous habitats. Such variables can be defined at the scale of community richness and diversity.

During the field trials and discussions with participants, their associations and diving clubs, as well as national MPA authorities, it became evident that a considerable proportion of divers, especially in the eastern Mediterranean, were not aware of the existence and importance of coralligenous assemblages despite the fact that these formed their preferred diving spots. The educational module of the project (i.e. guidelines and website) combined with the experience gained from the participation of divers directly raises public awareness. Experience from the field trials and past CS projects showed that knowledge exchange between citizen scientists and researchers promotes trust and facilitates application of marine conservation schemes (Arvanitidis et al. 2011, Thiel et al. 2014). Participation to monitoring CS projects can itself have a positive effect on recreational participants’ knowledge level and environmental awareness (Branchini et al. 2014). Establishing communication with users is also important for the optimization of the protocol and reporting of possible bugs in the website.

Charismatic, flagship species (e.g. gorgonians, the dusky grouper) that thrive in coralligenous bioherms can raise the interest of recreational divers and greatly increase their awareness for the habitat as a whole, or their willingness to invest time for data recording. For example, in a recent citizen science project regarding the presence of red coral along the coasts of Italy, Bramanti et al. (2011) reported that 80% of the participants selected their diving location based on the presence of red coral. Furthermore, many volunteers dedicated several dives to estimate colony density and extent of mortality, an indication of the willingness to devote valuable diving time to activities related to conservation.

A recent review study by Thiel et al. (2014) on the role of citizen scientists in marine research showed that the motives of participating people vary, with personal satisfaction and public recognition being the most frequent ones (85% of cases) along with knowledge gaining (52%). In the present CS project these two motives effectively define the profile of the targeted citizen scientists – enthusiast divers – and are directly addressed through the design of the developed protocol, data sharing and data publication policies of CIGESMED. To this end, all participants will be fully acknowledged and in certain cases included as co-authors in resulting communications to scientific or general media. Divers with a high level of input, according to the online rewarding system, could further contribute as local collaborators supporting joined missions and monitoring activities.

A series of joint activities organized by the CIGESMED CS researchers, with selected motivated diving associations and MPA management authorities have been scheduled in Greece (e.g. Korinthiakos Gulf and National Marine Park of Zakynthos), France (e.g. Atelier Bleu - CPIE Côte Provençale, Ailes Sportives Airbus Helicopters, Septentrion Environnement), and Turkey (e.g. Derin and Doğa Diving Center, Engin Sea and Nature Sports Center). Those include photo-sampling of permanent quadrats, recording of environmental data (e.g. through the deployment of loggers) and recording of threats and impacts on a scheduled and systematic basis. Joint missions will further include training of the involved divers and demonstrating the proposed activities using the developed CS protocol and e-infrastructure. Furthermore, online photo-contests are to be periodically scheduled and high-quality photographs uploaded by users will be screened on the homepage of the website or could be used in future scientific and educational publications, always acknowledging the photographer. Combined with the CIGESMED for divers CS protocol, these activities, are expected to enhance the creation of long-term data series, increase public awareness and establish communication and knowledge exchange on a more trust-worth and permanent basis.

We are grateful to all citizen scientists and dive centres for participating in field trials (dives), discussions and questionnaire-filling during the preparatory phase of the project; from France (Clément Aldebert, Dorian Guillemain, Eric Vastine, Etienne Pont, Gisèle Chatelat, Jacky Dubar, Joëlle Fossati, Frédéric Sonnerat, Frédéric Zuberer, Laurent Vanbostal, Marielle Ferré, Marina Caillaud, Associations “Little Nemo” and “Atelier Bleu”), Greece (Kostas Konstantinidis, Pavlos Koutsis, Dennis Mohr, Fanis Nikoloudakis, Divers Paradise Diving Centre, Nero Sport Diving Centre and the rangers of the National Marine Park of Zakynthos) and Turkey (Mert Palaoğlu, Bülent Şelli Derin and Doğa Diving Center). We also thank diving clubs for their willingness to participate to the CIGESMED for divers CS initiative, including joined missions for monitoring coralligenous sites on a stable basis (Thessaloniki Dive Club, “Tethys” Association of Recreational Scuba Divers, and “OCEANOS” Association of Achaia Divers). Special acknowledgements are due to researchers and divers from France (Frédéric Zuberer, Sandrine Ruitton, Dorian Guillemain, Romain Bricout, Sylvain Le Bris and Véronique Lamare) and Greece (Yiannis Iliopoulos and Vasilis Lekkas) who provided high-quality photos for the guidelines, slates and website. We thank Jacky Dubar and Etienne Pont for their help in translating texts in Spanish and French, and Eleni Voultsiadou for her help in the Greek translation of the guidelines.

This work was supported by (a) CIGESMED: Coralligenous based Indicators to evaluate and monitor the “Good Environmental Status” of the MEDiterranean coastal waters, funded under the SeasEra Framework (ERAnet), by the French, the Greek and the Turkish governments, the French National Research Agency (ANR: 12-SEAS-0001-01/02/03), the General Secretariat of Research and Technology (GSRT: 12SEAS-12-C2), and TÜBİTAK (112Y393); (b) LifeWatchGreece infrastructure (MIS 384676), funded under the ESFRI Framework by the Greek Government (GSRT), National Strategic Reference Framework (NSRF); (c) the French ministry of superior education and research (LTVA PhD grant) and the CNRS (GG postdoctoral grant).

CIGESMED: Coralligenous based Indicators to evaluate and monitor the "Good Environmental Status" of the MEDiterranean coastal waters (coordination IMBE, CNRS, France)

Wrote first draft of the manuscript: VG, TD, EP, NM, IF, CA

Revised the manuscript: all

Supervised CS initiative: VG, TD, EP, CA

Designed CS protocol: TD, VG, MSi, GG, YI, MSa

Website development, design & administrators: NM, EP

System administration: RD, EP

Smartphone application development: IF, EP

Website support: VG, TD, GG

Website country managers: VG, EP and NM for Greece; GG, LTVA, RD and JPF for France; AD for Turkey

Wrote CS guidelines: GG, LTVA, CD, VG, TD, MSi, MSa, AD, MEC, JPF, RD

Designed slates (printed & web versions): GG, LTVA, RD, CD, NM

Translated website, guidelines & slates: all

Artwork preparation, logo design and photo-editing: EP, TD

Provided photographic material: YI, TD, VG, MSi

Designed rewarding system: MSa, VG, YI, CA

Organized field trials: GG, CD, AD

Website check and preliminary data submission: GG, VG, MSa, MSi, LTVA, YI, RD

Citizen Science WP leader: CA, JPF

Project coordinator: JPF