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Mediterranean Temporary Lagoon: Proposal for a definition of this endangered habitat to improve its conservation
Abstract
Coastal lagoons have been recognised as a priority habitat for conservation and have benefited from several conservation plans. Under the Mediterranean climate, some of these lagoons might dry out during summer due to drought events. We propose the term Mediterranean Temporary Lagoons (MTLs) for these ephemeral water bodies and discuss their definition and characteristics. This term emerged in France among its coastal zone managers, who now commonly use it for conservation purposes. It is used in both natural systems as well as most artificial salt ponds in abandoned saltworks.
In Europe, two directives have integrated lagoons as key targets to be preserved. Nonetheless, a certain discrepancy in the different definitions of lagoons has constrained joint actions. Indeed, while institutional definitions were originally derived from the scientific concept, their legislative and managerials meanings have been gradually modified and nowadays often differ from the original concept to create difficulties in the field. In addition, while it has been recommended to consider MTLs as a coastal lagoon habitat in the European Habitat Directive, its interpretation among EU member states is unsettled. Thus, clarifying lagoon habitats' terminology is required to ensure better management, monitoring and planning, and coordinate conservation actions.
We discuss the inclusion of MTLs in habitat 1150 by confronting scientific and institutional literature and propose a new framework to better delimitate lagoon habitat around the Mediterranean basin, integrating MTLs. MTLs represent a specific habitat that hosts a pool of stenoecious macrophytes of conservation interest like Althenia filiformis, Riella helicophylla or Tolypella salina.
... In Europe, apart from the WFD, another norm defines conservation objectives for coastal lagoons, with a different approach: the Habitat Directive (HD, European Union (EU) 1992). This directive does not include a size limit, so the question of small lagoons arises: most of them are not only without any protection status, but they are not even acknowledged, so inventories, quantification and qualification of these systems is needed (Latron et al. 2022). ...
... Despite some small local differences potentially affecting the three lagoons' hydrological functioning at small scale, we highlighted evidence of climate change such as the extension of the dry period, the occurrence of drought outside the summer season and the intensification of the rainy period over shorter periods. Such impacts are exemplified by the small size of the studied sites that function as temporary coastal lagoons sensu Latron et al. (2022). We also established that our case study lagoons have been subjected to increasing rural urbanisation over the past few decades and especially seasonal pressure linked to summer tourism. ...
Mediterranean coastal lagoons are affected by multiple threats (demographic pressures, eutrophication, climate change) expected to increase in the future and impact the ecosystem services provided. Conservation norms and scientific studies usually focus on large lagoons (> 0.5 km ² ) due to their economic importance, while they ignore smaller lagoons. These are poorly understood and often unprotected, despite their prevalence within the Mediterranean region and their importance. Qualitative and quantitative characterisation of small lagoons, in terms of functioning and sensitivity to global and local changes, are needed to develop appropriate management strategies. For this purpose, this work provides the first inventory of all Corsican lagoons and has investigated three of them of small size (Arasu, Santa Giulia, Balistra), characterised by contrasting anthropogenic contexts (highly modified/disturbed, medium disturbance, quasi -pristine). At the regional level, 91 of the 95 lagoons identified are < 0.5 km ² , making Corsica a good example for the study of small Mediterranean lagoons. The three case studies showed differences in their seasonal biogeochemical cycles and phytoplankton communities (biomass, diversity, photosynthetic efficiency). Arasu and Santa Giulia lagoons showed an increase in watershed urbanisation (+ 12% and + 6% in 30 years), high phytoplankton biomass, low diversity and blooms of potentially harmful dinoflagellates. Conversely, Balistra lagoon showed a good status overall, but some anthropogenic pollution sources within its watershed. This study demonstrates the importance of small lagoons at regional and Mediterranean scale, and provides knowledge on studied local sites but also potential applications elsewhere. The importance of an integrated approach considering lagoons within their adjacent connected systems (watershed and sea) and anthropogenic contexts is highlighted.
... Paradoxically, recreational activities and cultural aspects show positive impacts, maintaining the natural attractiveness of the lake ecosystem, although the esthetic value has a moderate negative impact. These factors are particularly attractive in preserved lakes, especially for individuals seeking recreational opportunities [62]. ...
Lentic ecosystems are highly vulnerable to anthropogenic disturbances, which can lead to ecological imbalances with the loss of native biodiversity. This research evaluated the impact of anthropogenic activities on water quality and the trophic status of the Pacucha Lagoon, Andahuaylas, Apurimac. Seasonal sampling was conducted at six strategic points on the surface and bottom of the lake, following standardized protocols, during both the dry and rainy seasons. Physical and chemical parameters, metal ions, chlorophyll-a, and trophic status were determined using the Carlson indices, and water quality was assessed through the WQI-PE. The quantification of anthropogenic impacts was performed using the Leopold matrix. Statistical analysis included descriptive methods, ANOVA, Pearson correlation, and PCA at 5% significance. The results classify the lake as having “Regular” water quality according to WQI-PE. Physical and chemical parameters remain within the Environmental Quality Standards (ECA-Peru), while heavy metal ions exceed the limits in both seasons. The system exhibits mesotrophic conditions that tend to become eutrophic during the rainy season, suggesting a favorable nutrient balance for biological productivity. Activities with the most significant adverse impacts include agricultural practices that involve the intensive use of agrochemicals, morphological alterations to the surrounding area, and unregulated aquaculture. The lack of effective regulatory mechanisms and a lack of commitment to conservation suggest a high risk of irreversible degradation of the Pacucha Lagoon ecosystem.
... may be constrained in their capacity to spread and compete or escape competition. We suggest that the high incidence of rarity in our flora may be influenced by numerous factors, including the intrinsic fragmentation of freshwater environments, such as temporary pools and ponds (Bagella, 2023;Latron et al., 2022), and the profound temporal oscillations of climatic conditions in the Mediterranean region, at least throughout the Tertiary and Quaternary Periods (Rodrigo-Gámiz et al., 2011;Tzedakis, 2007). As a result, many aquatic plants in the region are confined to small and fragmented habitats at the edge of their distributions and ecological ranges and are considered relicts (Tierno de Figueroa et al., 2013;Vargas et al., 2018). ...
... However, when securing healthy ecological conditions, these lagoons not only facilitate touristic water activities, but also create diverse habitats that support a wide array of marine species, while also serving as a platform for innovative conservation strategies [20][21][22]. ...
The Ayla Oasis in Aqaba, Jordan, is a major tourism and residential development project in Aqaba, Jordan, containing three artificial lagoons. This study explores the ecological sustainable development of Ayla Lagoons, focusing on the seawater and bottom sediment quality, and the bottom habitat, in addition to coral conservation and restoration initiatives. The flushing time, averaging 3.7 days for the Upper Lagoon and 2.4 days for the Middle Lagoon, plays a crucial role in maintaining water quality. These measures secure the well-being of all visitors and residents, while also preserving the marine biodiversity. The Upper, Middle, and Tidal Lagoons exhibit physiochemical properties in alignment with seawater characteristics of the Gulf of Aqaba. Sediment quality analysis shows organic carbon levels and grain size distribution vary among lagoons, indicating expected different energy conditions and a healthy environment. The lagoons support a diverse range of species, with a total of 2343 fish individuals belonging to 22 species across 17 families recorded. The comprehensive analysis of the Ayla Oasis lagoons’ seawater and sediment quality revealed a dynamic and resilient ecosystem. Ayla’s coral conservation and restoration initiative within its lagoons feature 166 reef balls, 5 coral nurseries, and 2 metal structures, all designed to foster marine biodiversity. The project demonstrates the effectiveness of Ayla Oasis’ environmental resilience and monitoring strategies, showcasing a commitment to sustainable management and environmental stewardship. These efforts reflect Ayla’s ongoing dedication to protecting and preserving the marine ecosystem, ensuring the long-term health of its coral reefs and surrounding marine life.
... (iii) what to do with abandoned Salinas (MC SALT)? In Mediterranean France, there is a growing interest in promoting spontaneous developments in Salinas, where salt extraction has been abandoned [8] and many of the ponds have developed into so-called temporary Mediterranean lagoons showing alternations between hydroperiods during the wet seasons and dry conditions in summer [31]. This is particularly the case for the smaller-sized Salinas. ...
This paper discusses how ecological restoration has been pursued through projects financed by L’Instrument Financier pour l’Environnement (LIFE) of the European Commission in Mediterranean and Black Sea coastal lagoon sites affiliated with the Natura 2000 network. While the LIFE programme started in 1992, the first project focusing on ecological restoration in a coastal lagoon setting in this eco-region was attributed in 1995. In total, 50% (27) of the 54 LIFE projects in the Mediterranean and Black Sea coastal lagoons comprised a worksite on ecological restoration. Eighteen finalized projects, all realized after 2008, have been sufficiently documented for our analysis. The ecological restoration works included (i) removing solid waste and alien invasive species, (ii) re-building lagoons, (iii) creating islets for bird colonies, (iv) restoring the hydrodynamics of the lagoons, and (v) restoring and protecting vegetation. The latter includes submerged aquatic vegetation in the lagoons, halophytes on tidal flats and in fringing salt marshes, freshwater marsh plants, and dune vegetation. Abandoned salt works (Salinas), originally created within the coastal lagoons or on their shoreline, represent significant areas that can be managed for conservation or restoration. Coastal lagoons are transitional waters, and successful restoration of water quality and aquatic communities must include the concept of the aquatic continuum. Combating eutrophication requires managing the watersheds of the lagoons to drastically decrease nutrient loadings. Unfortunately, these issues have only been marginally addressed by the LIFE projects, as they were too often limited by the perimeter of the Natura 2000 sites. In principle, the Water Framework Directive takes care of these issues and, according to an integrative vision, links them with the protected Natura 2000 sites. In practice, however, the LIFE projects and the water policies in the member states still suffer from sectorial approaches.
... Los estudios sobre charcas temporales se viene adelantando en desde hace algún tiempo en otras latitudes (Camacho et al., 2009;Latron et al., 2022;Prunier et al., 2011;Rodríguez et al., 2011;Sahuquillo & Miracle, 2011); sin embargo, en Colombia se destacan las investigaciones realizadas por Cohen et al. (2014) quienes registraron por primera vez para Colombia la especie Dendrocephalus affinis (Anostraca: Thamnocephalidae); por otro lado, Serna-Macías et al. (2019) estudiaron la biodiversidad de una charca estacional en la Guajira colombiana, encontrando representantes de siete órdenes y 28 géneros; Tamaris-Turizo et al. (2020) caracterizaron la diversidad biológica de cinco charcas temporales en la Guajira Colombiana; y Oliveros-Villanueva et al. (2021a, 2021b) registraron por primera vez para Colombia del "camarón hada" Thamnocephalus venezuelensis (Anostraca: Thamnocephalidae) y del "camarón almeja" Leptestheria venezuelica (Crustacea: Brachiopoda: Spinicaudata). Investigaciones relacionadas con el estudio zooplancton en ambientes temporales fueron publicadas por Fuentes-Reinés et al. (2019) y Fuentes Reines et al. (2021, quienes reportaron dieciocho especies de cladóceros en una charca temporal poco profunda en la Guajira colombiana y registró por primera vez para Colombia la presencia del copépodo planctónico de agua dulce Notodiaptomus maracaibensis. ...
Introducción:
Las charcas temporales son ecosistemas acuáticos variables en su estructura física y biótica, efímeros en el paisaje e importantes en el flujo de materia y energía. Los macroinvertebrados acuáticos constituyen el grupo más abundante y diverso en estos ecosistemas y requieren mayor estudio, particularmente en los trópicos.
Objetivo:
Evaluar la diversidad alfa y beta de las comunidades de macroinvertebrados acuáticos de seis charcas temporales durante dos épocas climáticas en el norte de Colombia.
Métodos:
En Magdalena, Colombia, hicimos seis arrastres aleatorios con redes manuales en la zona litoral, y seis arrastres en zigzag con redes tipo D en la zona lacustre; recolectamos macrofauna en tres lances con una draga Ekman; y muestreamos cada charca durante la alta precipitación (noviembre, 2020) y la baja precipitación (febrero, 2021).
Resultados:
Identificamos 3 358 individuos (13 órdenes, 39 familias y 68 géneros). La mayor abundancia y diversidad (N= 485, ⁰D= 32) durante la época de lluvia se presentó en Los Campanos, mientras que la charca Villa Leidy tuvo el mayor número de taxones comunes (18) y dominantes (14). En la época de sequía, la charca Los Trillizos presentó la mayor abundancia (533) y diversidad (43); mientras que Villa Leidy y El Miquito el mayor número de taxones dominantes (16). Las charcas tienen composiciones particulares (sin agrupamientos espaciales o temporales); el recambio de taxones es alto, y la correspondencia canónica se agrupa por temporada.
Conclusiones:
la composición de las comunidades de macroinvertebrados acuáticos de las charcas temporales son muy diversas, presentando alto recambio tanto espacial como temporal, reflejando altos valores de remplazo de taxones entre épocas climáticas. La zona litoral mantuvo una composición similar durante las dos temporadas.
This paper focuses on the challenges for the co-implementation of two European Union Directives, i.e., the Habitats Directive and the Water Framework Directive, for the management of Mediterranean coastal lagoons as protected areas. Many of these ecosystems are included in the Natura 2000 network, the largest network of protected areas in the world. Based on semi-structured interviews with 45 stakeholders from 41 institutions, the study identified five main types of perceived barriers: economic, political and socio-cultural, historical, administrative, and ecological. The study confirmed that the co-implementation of the Habitats Directive (HD) and the Water Framework Directive (WFD) in Mediterranean coastal lagoons generated multiple and interrelated barriers. Beyond their regulatory complexity, these EU directives confronted managers with deep operational challenges. First, mismatches between administrative and ecological boundaries weakened their ability to control key ecological processes such as nutrient flows. Second, the proliferation of indicators, often perceived as disconnected from local realities, reinforced the critique of a management by numbers approach. Finally, the widespread use of regulatory exemptions, while intended to adapt EU rules to local contexts, frequently fueled persistent mistrust among stakeholders, especially in historically degraded environments. These challenges were further exacerbated by a siloed organization of administrations, limiting coordination and adaptive management. Overall, these findings call for more integrated governance frameworks, a more critical and context-sensitive use of indicators, and greater transparency in derogation procedures.
By the end of the 20th century, many of the coastal lagoons along the French Mediterranean coast showed insufficient water quality and degraded ecosystem states due to anthropogenic impacts. Among these, nutrient over-enrichment, resulting in eutrophication, has been a major concern. The EU Water Framework Directive (WFD) has initiated public action to improve their water quality and ecosystem state using an approach rooted in restoration ecology. Here we analyze how this has been applied for the coastal lagoons in South France, considering eutrophication as an example of ecosystem degradation and oligotrophication as the corresponding trajectory for ecological restoration of the eutrophied coastal lagoons. Oligotrophication trajectories, initiated by the reduction of external nutrient loading, have resulted in a quick recovery (i.e., within 3 years) of integrative water column variables (Chlorophyll a, total N and P) and phytoplankton. Starting from hypertrophic systems, the oligotrophication trajectory is described by a sequence of three ecosystem states dominated respectively by (i) phytoplankton with bare non-vegetated sediments, (ii) opportunistic macroalgae, (iii) angiosperm and perennial macroalgae, punctuated by regime shifts between these ecosystem states. Nevertheless, the latter regime shift has not been observed for the most degraded ecosystems after 10-years oligotrophication. The N and P accumulated in sediments during eutrophication may also retard the ecological restoration. In shallow freshwater lakes, the phytoplankton-dominated and the angiosperm-dominated states are also characteristic for highly degraded and fully restored ecosystems states, respectively. In contrast, opportunistic macroalgae do not bloom in these systems. Hence, the alternative stable state model, used successfully for these lakes, cannot be applied straightforwardly for coastal lagoons. To be successful, ecological restoration should consider the legislative and societal questions as according the DPSIR framework it typically is a response of society. The conservation-oriented Habitats Directive systematically applies to coastal lagoons and the Birds Directive in some cases as well. The WFD approach is complementary to these more conventional nature conservation approaches. Collectively, local citizens and highly involved stakeholders strongly value the coastal lagoons and attribute very high importance to their regulating ecosystem services (ESs), while differences between stakeholder profiles are related to different perceptions and appreciations of cultural ESs. Hence, coastal lagoon ESs are very important for the different stakeholders and public policies aiming at the ecological restoration of these ecosystems may count on public support.
La typologie EUNIS (European Nature Information System) est une classification des habitats naturels, semi-naturels et anthropiques des secteurs terrestres et marins d’Europe qui a été élaborée à partir de classifications préexistantes.
Cette typologie est utilisable sur tout le territoire français métropolitain et sur tous types de milieux. La traduction en français, les mises à jour et les correspondances avec les typologies précédentes sont gérées par l’UMS PatriNat. Elles sont disponibles dans l’Inventaire national du patrimoine naturel : https://inpn.mnhn.fr/ (programme HABREF).
Ce guide est un outil d’accompagnement à l’identification des habitats avec la typologie EUNIS. L’objectif est d’atténuer les différences d’interprétation entre utilisateurs. Il permet à l’écologue généraliste de mieux appréhender cette typologie d’habitat et d’améliorer la rigueur et la reproductibilité des interprétations et identifications réalisées sur le terrain comme préalable aux inventaires, cartographies et suivis. À terme, cela permet d’entrevoir une bancarisation plus efficace des informations sur la distribution des habitats.
Ce guide présente la typologie EUNIS (Partie A). Il contient des clefs de détermination (Partie B) et des descriptions illustrées (Partie C) pour que l’observateur identifie les habitats jusqu’au niveau 3 de cette typologie. Les critères pour identifier un habitat ne requièrent pas de connaissances confirmées en botanique ou en phytosociologie. En complément, les habitats qui peuvent représenter des objectifs particuliers de conservation sont indiqués (Annexe).
Le niveau 3 de la classification EUNIS peut permettre d’identifier des habitats sans relevé floristique, donc toute l’année. Néanmoins, dans le cadre d’une démarche conservatoire (évaluation, suivi, action fine de gestion…), il peut être pertinent d’aller au-delà (par ex. niveaux 4 ou 5 d’EUNIS) ou d’utiliser par exemple la classification phytosociologique (prodrome des végétations de France). Ces informations sont disponibles sur le site de l’Inventaire national du patrimoine naturel : https://inpn.mnhn.fr/.
The International Union for Conservation of Nature (IUCN) Red List of Threatened Species includes assessment of extinction risk for 98 512 species, plus documentation of their range, habitat, elevation, and other factors. These range, habitat and elevation data can be matched with terrestrial land cover and elevation datasets to map the species' area of habitat (AOH; also known as extent of suitable habitat; ESH). This differs from the two spatial metrics used for assessing extinction risk in the IUCN Red List criteria: extent of occurrence (EOO) and area of occupancy (AOO). AOH can guide conservation, for example, through targeting areas for field surveys, assessing proportions of species' habitat within protected areas, and monitoring habitat loss and fragmentation. We recommend that IUCN Red List assessments document AOH wherever practical.
After World War II, twenty-nine coastal Salinas (122 km 2), located in the vicinity of coastal lagoons and in deltas, were exploited along the Mediterranean coastlines in South France. Today, only five of these are still actively producing salt, currently representing 175 km 2. Concomitant with the abandonment of many of the smaller Salinas, the larger Salinas in the Rhône delta (Camargue) strongly increased their surfaces at the expense of natural ecosystems, of which a part has also been abandoned after 2009. This paper documents these changes in landscape use by chronological GIS mapping and describes the fate of the 91 km 2 of abandoned Salina surfaces. The majority of this area (88 km 2) is included in the Natura 2000 network, among which most (74 km 2) has been acquired by the French coastal protection agency (Conservatoire du Littoral) to be designated as Protected Areas. Only a very minor part (< 1 %) has been lost for industry and harbour development. Managing abandoned Salinas as Protected Areas is a challenge, because of the different landscape, biodiversity conservation, natural and cultural heritages issues at stake. In two cases, abandoned Salinas have been brought back again into exploitation by private initiative thus allowing for the protection of original hypersaline biodiversity. In other cases, the shaping of the landscape by natural processes has been privileged. This has facilitated the spontaneous recreation of temporal Mediterranean wetlands with unique aquatic vegetation, and offered opportunities for managed coastal realignment and the restoration of hydrobiological exchanges between land and sea. In other areas, former salt ponds continue to be filled artificially by pumping favouring opportunities for waterfowl. This has often been combined with the creation of artificial islets to provide nesting ground for bird colonies protected from terrestrial predators.
Coastal lagoon types of Western Greece were allocated to a spectrum of meso to polyhaline chocked lagoons; poly to euhaline restricted lagoons; and euhaline restricted lagoons along the Ionian Sea coast. This diversity comprises wide ranges of physical, chemical and environmental parameters in a seasonal and annual scale, which explains the variability in the distribution of benthic macrophytes. Four different macrophyte assemblages were distinguished, characterized by annual or perennial species. Extensive statistical analysis showed that salinity and nitrate concentrations had a great impact on the composition and distribution of macrophyte assemblages into lagoon types that also changed their abundance on a seasonal and annual scale. During the monitoring period, an important salinity shift in a chocked lagoon might cause the gradual loss of Zostera noltii and its replacement by Ruppia cirrhosa. Restricted lagoons were characterized by higher species diversity, while the other three identified macrophyte assemblages were dominated by the angiosperms Ruppia cirrhosa and Cymodocea nodosa. This integrated study of coastal lagoons is likely to be broadly applicable, since it was based on important parameters affecting such ecosystems, and the provided links between macrophyte assemblages and abiotic factors are of critical importance to improve management and environmental policies.
Foz do Almargem and Salgados are two small, intermittently closed and open lakes and lagoons (ICOLLs) located in the Portuguese southern coast, both remaining isolated from the sea throughout great part of the year. Based on environmental and biotic parameters, the first lagoon was classified as mesotrophic, with a greater marine influence, while the second one was classified as hypereutrophic. The plankton relations and seasonal variation were examined in both lagoons aiming at understanding the biological patterns here present and relating them with the environmental conditions, as well as inferring possible top down or bottom up control in the communities, determining also in which alternative trophic state they are: a clean water lagoon, with submerged macrophyte vegetation; or a turbid water lagoon, with only phytoplankton as primary producer.
The plankton community greatly differs in the two lagoons. Salgados lagoon presented extremely high concentrations of phytoplankton, which form blooms throughout the year, mostly composed by potential harmful organisms. This lagoon also had very high densities of zooplankton. Phytoplankton and zooplankton density was always lower in Foz do Almargem. Rotifera, Ostracoda and Cladocera dominated the Zooplankton community in Salgados. In Foz do Almargem, Rotifera also dominates, together with other groups, such as annelids, crustaceans and mollusks larvae, which denotes a stronger marine influence. In both lagoons, organisms with body size inferior to 100 µm mainly composed the zooplankton. In Salgados lagoon, excess nutrient load induced a high density of phytoplankton, which is utilized by a high density of zooplankton, following a bottom-up control model. The lagoon clearly showed a permanent turbid water alternative state due to excess nutrients. On Foz do Almargem, the frequent openings of the inlet throughout the wet season caused strong physical disturbance, which prevented the development of a stable planktonic community.
The Lesina lagoon (southern Adriatic Sea, Mediterranean) is a coastal lagoon located in a highly intensified farming and tourist area. A monthly sampling was carried out in 1998 in five stations, representative of different hydrological features, in order to analyse phytoplankton composition and its relation to environmental parameters. Our results showed high spatial variability of abiotic variables. Phytoplankton abundances and biomass trends showed marked seasonality, with annual peaks occurring in late winter–early spring and summer periods. Phytoplankton blooms were due to the diatom Thalassiosira pseudonana and the dinoflagellate Prorocentrum cordatum. Statistical analyses showed that salinity and nutrients were the main factors affecting phytoplankton abundance and biomass. Phytoplankton dynamics was associated both to seasonality and the hydrodynamic regime of the system. Moreover, chemical–physical data were analysed together with those collected in the same stations in 2007, to compare their dynamics under different hydrological regimes. The two periods corresponded to the closure and opening, respectively, of canals connecting the lagoon to the sea. In general, abiotic variables (salinity, dissolved oxygen, pH, nitrate, phosphate and silicate concentrations) were significantly affected by the hydrodynamic regime. These data could provide a useful basis to complement the knowledge gained through current monitoring within the framework of the European Directives, as well as to implement conservation and management strategies of these transitional waters.
A large spectrum of coastal lagoon types with a wide range of environmental conditions is observed along the French Mediterranean coast. These comprise wide trophic and salinity gradients, ranging from oligotrophic to hypertrophic status, and from nearly freshwater to slightly above marine Mediterranean Sea water salinities, respectively. The statistical analysis of a long-term dataset, including water column variables and observations of macrophyte genera, showed that salinity, depth, and then trophic status, were important factors explaining the distribution of benthic macrophytes for the soft-bottom sediments in the 34 studied French Mediterranean lagoons. Based on this, we assumed that the vegetation succession along the eutrophication gradient was different according to the lagoon salinity ranges. Euhaline and polyhaline lagoons follow the well-known Schramm schematic model, where aquatic angiosperm such as seagrasses dominate under oligotrophic conditions, and opportunistic macroalgae and phytoplankton dominate under eutrophic and hypertrophic conditions. In oligohaline and mesohaline lagoons, the succession is probably an intermediate scheme between the successions observed in small temperate lakes and in marine coastal ecosystems due to the presence of both brackish and freshwater species. We thus propose a conceptual scheme for the oligohaline and mesohaline lagoons.
Accurate wetland datasets are indispensable for generating polices on wetland conservation and appropriate land uses, global climate change studies, and biodiversity conservation. Although increasing numbers of global wetland-related datasets have been established, the extensive disagreements among these datasets are prominent. In particular, estimates of global wetland area range from 0.54 to 21.26 million km² and the class-specific spatial consistency of wetlands is less than 1%. The different definitions of ‘wetland’ and the intrinsic features of wetlands contribute to this extensive inconsistency. Given the various requirements of wetland-oriented data products, it is important to conduct comprehensive wetland mapping at global scale. The Ramsar wetland definition is recommended and a hierarchical and flexible structure of wetland classification system is preferred for future global wetland datasets. Time-series satellite imagery at 250–1000 m spatial resolution is preferred to characterize wetland dynamics by combination of passive/active SAR data and other ancillary data, such as topography, climate, and soil data. The classification tree method for classification of massive satellite imagery and big-data technology for sample datasets are promising for the enhancement of wetland map product accuracy.
p>The existence of strong potential synergies between the Water Framework Directive (WFD) and the Habitats Directive (HD) is widely acknowledged. Indeed, ensuring favourable conservation conditions for aquatic habitats and species of conservation concern is closely related to the achievement of a good ecological status in water bodies. However, since these two sets of European laws are generally applied without any coordination, an inefficient use of resources may adversely affect their goals. The main negative outcome is an increase in the cost of monitoring programs for collecting data in nature ( i.e. , physical and chemical parameters, species and habitats, plant communities). The use of macrophytes as a bioindicator, as imposed by the WFD, may instead help to integrate data on aquatic EU habitats and enhance knowledge of such habitats outside the Natura 2000 network. The aim of present study was to evaluate the usefulness of data collected in WFD monitoring surveys as a means of inferring the occurrence and the distribution of lacustrine aquatic habitats in countries belonging to the European Union (EU). The main aim of the analysis was to identify the depth gradient distribution of diagnostic macrophyte taxa in two EU habitats (3140, i.e. , Chara -dominated benthic communities, and 3150, i.e. , natural eutrophic lakes) using data collected in lakes in Lombardy (northern Italy), some of which are included in the Natura 2000 network (10 out 16). While recognizing the limitations of the data collected within the two frameworks, the results confirmed the marked usefulness of WFD data as a means of enhancing the knowledge available on lacustrine aquatic habitats in the EU. WFD data can actively help to improve the basic information on aquatic habitats, thereby more effectively supporting regional strategies for biodiversity conservation as well as recovery programs.
</p
The existence of strong potential synergies between the Water Framework Directive (WFD) and the Habitats Directive (HD) is widely acknowledged. Indeed, ensuring favourable conservation conditions for aquatic habitats and species of conservation concern is closely related to the achievement of a good ecological status in water bodies.However, since these two sets of European laws are generally applied without any coordination, an inefficient use of resources may adversely affect their goals. The main negative outcomeis an increase in the cost of monitoring programs for collecting data in nature (i.e., physical and chemical parameters, species and habitats, plant communities). The use of macrophytes as a bioindicator, as imposed by the WFD, may instead help to integrate data on aquatic EU habitats and enhance knowledge of such habitats outside the Natura 2000 network.The aim of present study was toevaluatethe usefulnessof data collected in WFD monitoring surveys as a means of inferring the occurrence and the distribution of lacustrine aquatichabitats in countries belonging to the European Union (EU). The main aim of the analysis was to identify the depth gradient distribution of diagnostic macrophyte taxain two EU habitats (3140, i.e., Chara-dominated benthic communities, and 3150, i.e., natural eutrophic lakes) using data collected in lakes in Lombardy (northern Italy), some of which are included in the Natura 2000 network (10 out 16).While recognizing the limitations of the data collected within the two frameworks, the results confirmed the marked usefulness of WFD data as a means of enhancing the knowledge available on lacustrine aquatic habitats in the EU. WFD data can actively help to improve the basic information on aquatic habitats, thereby more effectively supporting regional strategies for biodiversity conservation as well as recovery programs.
Although seagrasses cover only a minor fraction of the ocean seafloor, their
carbon sink capacity accounts for nearly one-fifth of the total oceanic
carbon burial and thus play a critical structural and functional role in
many coastal ecosystems. We sampled 10 eelgrass (Zostera marina) meadows in Finland and 10
in Denmark to explore seagrass carbon stocks (Corg stock) and carbon
accumulation rates (Corg accumulation) in the Baltic Sea area. The study
sites represent a gradient from sheltered to exposed locations in both
regions to reflect expected minimum and maximum stocks and accumulation. The
Corg stock integrated over the top 25 cm of the sediment averaged 627 g C m−2 in Finland, while in Denmark the average Corg stock was over
6 times higher (4324 g C m−2). A conservative estimate of the total
organic carbon pool in the regions ranged between 6.98 and 44.9 t C ha−1.
Our results suggest that the Finnish eelgrass meadows are minor carbon sinks
compared to the Danish meadows, and that majority of the Corg produced in
the Finnish meadows is exported. Our analysis further showed that
> 40 % of the variation in the Corg stocks was explained by
sediment characteristics, i.e. dry density, porosity and silt content. In
addition, our analysis show that the root : shoot ratio of Z. marina explained
> 12 % and the contribution of Z. marina detritus to the sediment surface
Corg pool explained > 10 % of the variation in the Corg stocks.
The mean monetary value for the present carbon storage and carbon sink
capacity of eelgrass meadows in Finland and Denmark, were 281 and 1809 EUR ha−1, respectively. For a more comprehensive picture of
seagrass carbon storage capacity, we conclude that future blue carbon
studies should, in a more integrative way, investigate the interactions
between sediment biogeochemistry, seascape structure, plant species
architecture and the hydrodynamic regime.
This paper investigated the hydrodynamics, spatio-temporal variability of temperature/salinity and the
residence time of tracer concentrations in a largest brackish water coastal lagoon in Asia, namely the
Chilika lagoon, India. An integrated approach combined the measurement and 2D hydrodynamic-advection/
dispersion model is used to simulate circulation and temperature/salinity, and estimated the
water residence time in lagoon under different forcing mechanisms, such as tide, wind and freshwater
discharge during the dry and wet periods. Water circulation inside the lagoon is simulated when wind is
included with the tide only forcing during dry period, and freshwater influx is included with the tide and
wind forcing during wet period. Under the realistic forcing conditions, the computed temporal variability
of water temperature and salinity are well correlated with the measurements in both the periods. The
spatial variations of water temperature within the lagoon is influenced by the meteorological conditions,
tide and freshwater influx as well as the shallowness of the lagoon, whereas the salinity is spatially
controlled by the freshwater influx from the riverine system and seawater intrusion through the tidal
inlets. The numerical model results show that in the Chilika lagoon tidal and river influx affect significantly
the residence time spatially, and is site specific. The residence time varies from values of 4–5
days in the outer channel (OC) and 132 days at the northern sector (NS) in the main body of lagoon. The
current study represents a first attempt to use a combined model approach, which is therefore, a useful
tool to support the ecological implication of the lagoon ecosystem.
The rare aquatic liverwort Riella helicophylla (Bory et Mont.) Mont., inhabitant of temporary shallow ponds around the Mediterranean basin, is considered threatened throughout its distribution range. In addition, little is known of its biology and ecology or of its role in such an important ecosystem where environmental conditions vary yearly in unpredictable ways. In these variable habitats, due to the seasonal fluctuation of water levels, there is no guarantee of yearly spore input into the spore bank. Spore germination rate and the effects of different culture media in an axenic culture establishment, as well as propagation procedures of R. helicophylla, were tested. New insights into the ecology and biology of R. helicophylla are given. Spore dormancy is documented, and the protocols for the in vitro culture establishment, propagation and acclimatization of this liverwort are developed. Dry storage at 20±2ºC for about three months broke the dormancy of spores, which subsequently germinated in a high percentage (over 90%). A two phase (solid and liquid) culture media system was developed for the purpose of achieving fully developed gametophytes. The liquid phase contained electrolytes simulating brackish water.
The EU water framework directive (WFD) is intensively connected with other European legal regulations and supporting documents. This close interrelationship calls for deeper considerations when WFD is implemented in locations of high conservation value, e.g. Natura 2000 sites. A comprehensive, but specific comparison of the goals of WFD with the aims of habitats directive (HD) and birds directive (BD) provides a sensitive overview on their peculiarities, with an outlook on potential synergies and conflicts. The sometimes complex guidance for solving complicated situations in the practical application of these differing legal provisions is also described. The representation of requirements for Natura 2000 sites as part of river basin management plans, and related up-to-date experience are given special attention. Finally recommendations and conclusions provide the reader with a complete view of this challenging chapter in European Policy. In the end, considerably more synergies than conflicts are identified between the objectives of WFD, HD and BD. Whenever conflicts should arise these directives prevent derogating from their requirements by cross-references. Therefore, firm and timely coordination between water and nature conservation authorities is necessary.
A 1-year cycle of physico-chemical measurements was conducted in the Marano and Grado Lagoon (Adriatic Sea, Italy) with the aim to assess its trophic state. Some selected variables (nutrients, chlorophyll a, dissolved oxygen, temperature and salinity) were used to describe the system within the application of the Water Framework Directive (WFD) and to compare it with other Mediterranean environments. From an ecological point of view the Marano and Grado Lagoon is one of the best conserved wetlands in the whole Mediterranean area and is protected by several European environmental pieces of legislation. However, the neighbouring mainland hosts several socio-economic activities which can affect its water quality. The results obtained in this work highlighted considerable spatial and temporal variability of physico-chemical parameters. Specifically, a large amount of anthropogenic nutrients, mainly in form of nitrogen (N), was carried from inland through river discharges in the Marano basin (western sector). However, these inputs were offset by the water exchange with the adjacent open sea, which exerted a dynamic dilution effect, and induced low water residence time thus limiting nutrients enrichment and their accumulation for long time periods. The Molar Redfield ratio (DIN/SRP) was always higher than the optimum value of 16 (in some cases it was up to 2000), thus suggesting that the system is phosphorus (P) limited, as confirmed by low chlorophyll a content, rare algal blooms and good water oxygenation. Trophic state indices and threshold values (EEA method, Carlson Trophic Index, TRIX and ASSETS) were applied. A broad range of classes was found (from oligotrophic to hypertrophic depending on water bodies, method applied and period of the year), thus suggesting that an over simplification of this complex ecosystem should be avoided. Further studies will be conducted in order to define the Lagoon's ecological status sensu WFD and the adequate management implications.
European integration has consequences for environmental planning in the European Union. Recent evaluations of the European Commission show that implementation of environmental directives proves to be a challenging task for the responsible authorities. This paper discusses the relation between the implementation of the Water Framework Directive and the Birds and Habitats Directives in The Netherlands. Studies from this member state show that legal and procedural aspects of planning and decision making gain the most attention and that environmental goals are fading into the background. We study the integration of the two directives from a policy and practice perspective and discuss the difficulties that arise in the implementation process. Copyright © 2009 John Wiley & Sons, Ltd and ERP Environment.
Coastal lagoons are inland water bodies, found on all continents, usually oriented parallel to the coast, separated from the ocean by a barrier, connected to the ocean by one or more restricted inlets which remain open at least intermittently, and have water depths which seldom exceed a few meters. A lagoon may or may not be subject to tidal mixing, and salinity can vary from that of a coastal fresh-water lake to a hypersaline lagoon, depending on the hydrologic balance. Lagoons formed as a result of rising sea level mostly during the Holocene and the building of coastal barriers by marine processes. They are often highly productive and ideal systems for aquaculture projects but are, at the same time, highly stressed by anthropogenic inputs and human activities.
Recent advances in research tools for the systematic analysis of textual data are enabling exciting new research throughout
the social sciences. For comparative politics, scholars who are often interested in non-English and possibly multilingual
textual datasets, these advances may be difficult to access. This article discusses practical issues that arise in the processing,
management, translation, and analysis of textual data with a particular focus on how procedures differ across languages. These
procedures are combined in two applied examples of automated text analysis using the recently introduced Structural Topic
Model. We also show how the model can be used to analyze data that have been translated into a single language via machine
translation tools. All the methods we describe here are implemented in open-source software packages available from the authors.
In this review paper the present status of coastal lagoon and future challenges which will be faced by the coastal lagoon is discussed. Coastal lagoon provides great livelihood for a larger portion of human population through fisheries and tourism point of view thus crucial in socio economic aspect. Due to natural and anthropogenic activity, stress on coastal lagoon is increasing day by day. Thus steps should be taken for regular monitoring and planning for better management is found to be imperative in regards to present day situation.
Tolypella salina R. Cor. is a Charophyte only known from some French and Iberian stations. Its rarity and the
specific richness of the salt marshes where it grows, on the Atlantic and Mediterranean coasts, have led to the proposal to add this species to the French list of protected plants. A survey of stations was realized on the Atlantic coast (Noirmoutier, Guérande) between 2010 and 2013 to complete the distribution map of this taxon. The aim of this work is to improve the knowledge of this plant’s biology and its ecological environment. It appears that the development of this species differs between stations, and also from one year to the next, a phenomenon due to the instability of its living environment (hydrological and salinity conditions, etc.). Phytosociological considerations related to the subassociation tolypelletosum salinae are added. Some recommendations are proposed for the management of these sites, taking into account the human activities there, in order to maintain the salt marsh mosaic that is necessary for the conservation of
Tolypella salina.
Changes in the perception and goals of nature conservation require a solid scientific basis
Temporal variability is widely acknowledged as a main source of uncertainty and error in ecological studies. Despite this, conservation management tends to overlook the temporal dimension of ecosystems due to financial and operational constraints. The main aim of this study is to identify potential biases in the implementation of the European Water Framework Directive due to temporal variability in water-chemistry parameters. Specifically, we focused on the establishment of water-bodies typologies and the assessment of water quality in transitional waters. We measured water-chemistry (salinity and nutrients) in 34 coastal lagoons on a monthly basis over a full year (March’08–February’09) in a Mediterranean archipelago (Balearic Islands, Spain). We found large differences in nutrient levels among both the coastal lagoons of different islands (Majorca, Minorca, Ibiza and Formentera) and lagoons of different salinity types (euhaline, mesohaline and oligohaline). From an applied perspective, our results show that monthly values were inadequate for determining salinity-based typologies, as lagoon salinity values varied widely from month-to-month. Additionally, we found a lack of agreement between ecological assessments based on invertebrates and those based on nutrient thresholds often used for transitional waters. These facts highlight the need for a definition of specific thresholds for coastal lagoons which are not currently available.
A multi-proxy approach study (cladocerans, diatoms, geochemistry, plant macrofossils, pollen), was performed on a sediment core from Lake Vrana (Vransko Jezero), a large and deep karstic lake on the northern Adriatic island of Cres, Croatia. Considerable lake-level changes occurred during the last approx. 16,000 years. The stratigraphic evidence suggests that periods of enhanced pre- cipitation and the post-LGM rise in sea level were the main driving forces. The lake records indicate early human impacts. Sediment echo-sounding indicated that >25 m of lake sediments lies within the site, from which 5 m have been cored. Shallow lake stages oc- curred from 14.4 14C ky BP to early Holocene. Prior to Alleröd, interglacial sediments were redeposited, reflecting the influences of rising sea-level (forming a local groundwater barrier), a temporary increase in precipitation, and lake-level changes. There appears to be a hiatus in the sequence, for no sediments assignable to the Alleröd chronozone could be found. A discordance in the echo pro- file at the appropriate horizon in the sequence supports this interpretation. Groundwater level increased again at 10.6 ky BP (during Younger Dryas chronozone), a swamp vegetation formed, which gave way to a shallow lake. During the Preboreal chronozone, this freshwater lake persisted with fluctuating levels. The establishment and subsequent persistence of the present deep water lake at about 8.5 ky BP, correspond with findings of a pluvial period at the Dalmatian coast, which lasted from 8.4 to 6 ky BP. First human catchment disturbances were related to settlements of Neolithic or Bronze Age. The increase in summer drought, coupled with forest clearance during Illyrian times, are assumed to be responsible for the change towards present evergreen oak vegetation in the lake catchment. The intensification in land-use during Roman and post-Roman settlements caused a slight increase in the lake trophic level.
This study focuses on the presence and distribution of the species of Tolypella genus in the Iberian Peninsula through a literature review and the examination of environmental, botanical and physicochemical data of the locations where T. salina, T. prolifera, T. intricata, T. hispanica and T. glomerata are settled. The shortage of herbarium material means that new collections are required to be able to conduct more detailed studies in the future, particularly on T. prolifera and T. intricata, of which the biological traits, ecology and distribution are poorly known in the Iberian Peninsula.
We provide a cartography of the current property regimes of permanent coastal lagoons along the coastlines of the Mediterranean Sea for continental France and Corsica, which include both private and public properties. In France, for the latter, the State Domain Code and the General Code of the property of public persons make a clear difference between Public Domain and private property of the different public entities. Public domain represents property that is imprescriptible and inalienable, i.e. the property rights cannot be changed in the future and neither transferred nor sold to somebody else. In contrast, private properties of public entities can be sold or transferred to thirds. Maritime Public Domain (DPM) was created since 1681. DPM has accommodated Public Domain for the French coastal lagoons following their legal definition as “salty ponds (French étangs salés) with a direct, natural and permanent connection with the sea”. However, private landlords battled juridically with the State for centuries both by attacking the pertinence of this definition and claiming ancestral property rights. As a result, before 1980, more than half of the coastal lagoons comprised private properties, representing about a quarter of the lagoon surface. Twelve of 40 coastal lagoons comprise DPM, mainly the larger lagoons (e.g., Salses-Leucate, many lagoons close to Narbonne, Thau lagoon, Berre lagoon), representing 65% of the total lagoon surface. Since its foundation in 1975, the Conservatoire du Littoral, a public body in charge of coastal nature protection, has bought private coastal lagoons properties in twenty of 40 lagoons, representing 22% of the total lagoon surface. These have been designated as inalienable and imprescriptible “Public Domain of the Conservatoire”, safeguarded for nature conservation purposes. Nowadays, private ownership still persists in 13 lagoons representing 3.3% of total surface. The Coastal lagoons in Roussillon (Etangs du Canet and Salses-Leucate), the Hérault department, in the Camargue and in Corsica currently show variable and sometimes fragmented ownership (in addition to the Conservatoire, DPM, private ownership, municipalities, departments). Fragmented ownership is a clear difficulty for the integrated management of coastal lagoons. With currently, 87% of the coastal lagoons as Public Domain, public law and the environmental code have to evolve to tackle the challenges for the conservation and management of coastal lagoons and their connectivity with the other ecosystems on land and in the sea.
Wetlands conservation and resilience capacities are key issues in many places over the globe. Understanding these issues will benefit from a precise knowledge of seagrass species occupancy and coverage over time and over space. Such information can be obtained from remote sensing images and their classification thanks to a vegetation index, to be used in a complementary manner to field work inventories. Sentinel-2 data, which are available with a frequent revisit time (<5 days) and a high spatial resolution (10m pixel size) can be used to map grassbeds at the surface or slightly below the surface of permanent lagoons, hence enabling the characterization of its seasonal dynamics, which was not possible with previous remote-sensing tools. We have proved the feasibility of such a method in the natural reserve of the Bagnas (Herault, France) where Stuckenia pectinata coverage can be tracked over a full year thanks to Sentinel-2 images and field work. Inter-annual dynamics (seasonal growth and senescence) can be mapped over time with 10m resolution and will be extended to pluriannual studies thanks to the long-term objective of the Sentinel-2 mission. This opens the way to a concerted management of natural reserves based on data analysis and field knowledge, a better understanding of seagrass coverage with fluctuating environmental conditions, and predictive mechanistic and/or stochastic models of future qualitative trends.
Many of our old assumptions concerning coastal lagoons, such as
their ecological simplicity and uniformity, and the processes that affect their functioning, are fading as our knowledge and understanding of their ecological complexity increase and their heterogeneity becomes more evident (P´erez-Ruzafa et al., 2019a). These properties are linked to their capacity to contribute to one of the highest biological productivity systems known among marine ecosystems, accompanied by their high resistance and resilience in the face of environmental and anthropogenic pressures. All this translates into an important provision of ecosystem services and social goods. However, we are still far from assessing their importance in management policies and regulations, for example those of the European Union. This is probably due to our poor understanding of the relationship between human activities that exploit these goods, the geomorphological and environmental changes that such activities produce and their consequences for the hydrographical and ecological processes that allow the said resources and services in the beginning.
The seventh edition of the European Congress on Coastal Lagoons
(7th Eurolag, Murcia, Spain, March 2016), held under the slogan
"Vindicating the biological and socioeconomic importance of transitional waters", while highlighting the biological importance of these ecosystems, also emphasized their importance for the culture, economy and society of the geographical areas in which they are located.
The charophyte flora of Italy is insufficiently known. This paper reports the results of a survey of the historical and recent distribution of Characeae in Sardinia, in order to fill current knowledge gaps. Information about the study area and the database is presented. The study focused on brackish water bodies with a special emphasis on lagoons and temporary brackish pools as well as on freshwater habitats. Between 1988 and 2018 more than 500 water bodies have been investigated. Characeae were recorded in 212 sites. In total, the occurrence of 26 Characean species was verified. They belong to four genera: Chara (13 taxa), Nitella (seven), Tolypella (four) and Lamprothamnium (two). The abundance of the species is discussed and information about their habitats and distribution is given. Distribution maps for selected taxa are presented. During this study Lamprothamnium succinctum was recorded for the first time in Europe. Tolypella salina and Chara baltica were verified as new species for Italy. Moreover, Nitella confervacea and Chara connivens, neither of them recently reported, are confirmed for Italy. A new sexual population of Chara canescens was discovered. As a result of the present study the total number of Characean species known for Sardinia has been increased from 15 to 26. Many taxa, especially nine species closely linked to brackish habitats, are currently very rare throughout Italy. Threats and pressures on Characeae and their habitats in Sardinia are discussed and appropriate actions for their conservation are proposed.
Oligotrophic coastal zones are disappearing from increased nutrient loading. The quantity of nutrients reaching the coast is determined not only by their original source (e.g. fertilizers used in agriculture, waste water discharges) and the land use, but also by the pathways through which nutrients are cycled from the source to the river mouth. In particular, lakes sequester nutrients and, hence, reduce downstream transfer of nutrients to coastal environments. Here, we quantify the impact of Aquitaine great lakes on the fluxes of dissolved macro-nutrients (N, P, Si) to the Bay of Biscay. For that, we have measured nutrient concentrations and fluxes in 2014 upstream and downstream lakes of Lacanau and Carcans-Hourtin, which belongs to the catchment of the Arcachon Bay, which is the largest coastal lagoon of the Bay of Biscay French coast. Data were compared to values obtained from the Leyre river, the main freshwater and nutrient source for the lagoon. Results show that processes in lakes greatly limit nutrient flux to the lagoon compared to fluxes from Leyre river, although the watershed is similar in terms of land cover. In lakes, phosphorus and silicon are trapped for long term in the sediment, silicon as amorphous biogenic silica and phosphorus as organic P and P associated with Fe-oxides. Nitrogen that enters lakes mostly as nitrate is used for primary production. N is mineralized in the sediment; a fraction diffuses as ammonium. N2 production through benthic denitrification extracts only 10% of dissolved inorganic nitrogen from the aquatic system. The main part is sequestered in organic-rich sediment that accumulates below 5 m depth in both lakes.
Mediterranean coastal lagoons are among the most productive of marine ecosystems but, at the same time, they are strongly affected by anthropogenic pressures that could alter their fisheries. This work looks at how the Mar Menor coastal lagoon fishery evolved from the eighteenth century to 2012, and provides data about landings, effort and gears. The relationships between fishing yields and the environmental consequences of the most important human activities in the lagoon (including the dredging and widening of inlets in the last two centuries and eutrophication episodes in the 1990s) are examined using uni- and multi-variate analysis. While mean total yield tended to remain constant, significant changes in the specific composition of the catch and in the dominance of the main target species have occurred. The lagoon seems to have the ability to support a wide range of pressures and environmental changes, since it has been seen to recover each time from specific human impacts, maintaining the fishery yields close to the total maximum sustainable yield. However, other factors, like climate change or the spread of aquaculture exploitations, may have overlapping effects, introducing long term trends in the fisheries concerned.
Mapping of habitats with relevance for nature conservation involves the identification of patches of target habitats in a complex mosaic of vegetation types not relevant for conservation planning. Limiting the necessary ground reference to a small sample of target habitats would greatly reduce and therefore support the field mapping effort. We thus aim to answer in this study the question: can semi-automated remote sensing methods help to map such patches without the need of ground references from sites not relevant for nature conservation? Approaches able to fulfill this task may help to improve the efficiency of large scale mapping and monitoring programs such as requested for the European Habitat Directive.
In the present study, we used the maximum-entropy based classification approach Maxent to map four habitat types across a patchy landscape of 1000 km2 near Munich, Germany. This task was conducted using the low number of 125 ground reference points only along with easily available multi-seasonal RapidEye satellite imagery. Encountered problems include the non-stationarity of habitat reflectance due to different phenological development across space, continuous transitions between the habitats and the need for improved methods for detailed validation.
The result of the tested approach is a habitat map with an overall accuracy of 70%. The rather simple and affordable approach can thus be recommended for a first survey of previously unmapped areas, as a tool for identifying potential gaps in existing habitat inventories and as a first check for changes in the distribution of habitats.
We compared the uses and definitions of habitat-related terms in 50 articles from 1980 to 1994 to operational definitions we derived from the literature. Only 9 (18%) of the arti- cles we reviewed defined and used habitat-related terms consistently and according to our definitions of the terms. Forty-seven articles used the term "habitat;" however, it was only defined and used consistent with our definition in 5 articles (11%) and was confused with vegetation association or defined incompletely in 42 papers (89%). "Habitat type" was the term most commonly used incorrectly; 16 of 17 times (94%) it was used to indi- cate vegetation association, but habitat and vegetation association are not synonymous. Authors did not provide definitions for habitat use, selection, preference, or availability 23 of 28 times (82%). We concluded that habitat terminology was used vaguely in 82% of the articles we reviewed. This distorts our communication with scientists in other dis- ciplines and alienates the public because we give ambiguous, indefinite, and unstandard- ized answers to ecological questions in public and legal situations. Scientists should de- fine and use habitat terminology operationally, so that the concepts are measurable and accurate. We must take the challenge to standardize terminology seriously, so that we can make meaningful statements to advance science.
The Prévost lagoon (Mediterranean coast, France), was subject to annual dystrophic crises caused by the biodegradation of opportunistic macroalgae (Ulva lactuca) in the past. These crises result in anoxic waters with subsequent blooms of Purple Sulphur Bacteria (red waters) which, by oxidizing sulphide, contribute to the reestablishment of oxic conditions in the water column. Mechanical dredging of the macroalgal biomass has been carried out in the lagoon since 1991 with the aim of preventing the ecological and economic disturbances caused by such crises. Dredging began just before the phototrophic bloom when the water was already hypoxic (O2 = 0.7 mg·L−1) and contained sulphilde (H2S = 7.3 mg·L−1) and purple patches of phototrophic bacteria (Thiocapsa sp.) that were beginning to develop on decaying macroalgae at the sediment surface. The dredging prevented red water formation and drastically modified both phototrophic community structure and activity and biogeochemical sulphur cycling. The dredging permitted the reestablishment of oxic conditions for a short period only (1–13 August). Resuspension of the superficial sediment layers disturbed the phototrophic bacterial community, whose numbers decreased by one order of magnitude (from 2 × 106 to 3.9 × 105 CFU.mL−1). The phototrophic community was no longer effective in reoxidizing the reduced sulphur compounds remaining in the sediments, as shown by a drastic sulphate depletion in the superficial sediment layers. Moreover, the increase in the specific bacteriochlorophyll a concentration of the phototrophic purple bacteria and the rapid development of Green Sulphur Bacteria (Prosthecochloris-like microorganisms) indicated that the phototrophic community was growing under severe light-limiting conditions due to the resuspension of sediment particles in the water. These conditions did not allow the phototrophic bacterial community to efficiently reoxidize the reduced sulphur compounds originating from the sediments. In consequence, hypoxic conditions (O2 = 4.7 to 4.8 mg·L−1) and low sulphide concentrations (H2S = 0.4 to 0.7 mg·L−1) were detected in the water column until September. The ecological balance in the lagoon was reestablished only in October, whereas, in previous years it had been restored in August.
The uptake and/or release rates of carbon (C). nitrogen (N). phosphorus (P) and sulphur (S) during Ura rigida growth and/or decomposition. were determined in two different nutrient-enriched areas of the Venice lagoon. The field investigation included 20 experiments subdivided in four different seasonal periods. Experiments were carried out by suspending 150g fw of Viva biomass in 12 net wire cages. 6 fixed at the surfiace and 6 at the bottom of each area studied. Weight determinations and collection of samples from the cages for the nutrient tissue analysis were carried out at 4-10 day intervals, depending on the season. Temperature, light and the nutrient concentrations in the whole water column as well as in the surface sediment porewater were also determined. The daily cage and in situ biomass variations (DBVs) were up to 23% and 137%. respectively. The rates of biomass production were 2-3 limes higher in the more nutrient-enriched area and within the cages suspended close to the water surface. The rates of the daily nutrient uptake by Vha tissue were up to 43% for P, 19% for K. 6.8% for C and 9.3%.: for S. Significant (P < 0.01) correlation coefficients between the environmental and tissue nutrient concentrations and the biomass increase and/or decrease were found. However, besides interesting data suggesting a phosphorus (from tissue N : P atomic ratios up to 61 : 1 and P water concentrations < 1 μmol L ') or a nitrogen (from critical biomass N concentrations < 20 mg dw 1J growth limitation, no effective limitations in the biomass production were monitored. These results confirm previous results on the key role of the water renewal by tides and of the nutrient fluxes from the water-sediment interface as the main factors controlling the availability of nutrient elements for the algal growth in the Venice lagoon.
C/N ratios of organic matter sources in coastal lagoons and their drainage areas in the southern Baltic Sea region are investigated to determine the origin of organic matter (i.e. terrigenous or marine) in the sediments of the lagoons. These ratios are compared with δ13C values in the area. Terrestrial plants in the study area show C/N ratios between 10 and 85, whereas aquatic macrophytes have values in the range of 6 to 44. Peat and shore vegetation have C/N ratios between 15 and 16, and plankton shows values close to 6. In conjunction with δ13C values, the C/N ratios in the sediments allow the reconstruction of the Holocene palaeoenvironments and palaeoecology in the lagoons (Oder Estuary and Greifswalder Bodden). Distinct stages in the development of the water bodies, resulting from sea level changes in the region, can be derived: post-glacial lake stages with sandy sedimentation, lacustrine phases with high autochthonous productivity, terrestrial stages with peat formation, sedimentation as a result of marine transgression, and brackish sedimentation after the formation of sand spits and barrier islands. The application of Corg/Ntot ratios instead of Corg/Norg does not have any significant influence on the interpretation of the data and may thus be used in the coastal sediments of the southern Baltic Sea after having applied the test procedures presented in this study.
Althenia filiformis Petit is a habitual colonizer of brackish water. In Sardinia, at least, it is annual and dependent on sexual reproduction. Seeds remain in the fruit and germinate underwater. Some seeds germinate while still on the mother plant, others after a period of desiccation; low temperatures or periods in darkness induce germination of dormant seeds. Althenia is not able to utilize HCO3− and is dependent on CO2 as a carbon source. The leaves reach the water surface where they not only get CO2, but are exposed to considerable wave action. They thus have relatively large marginal bundles of fibres. Althenia is monoecious, but some male and female flowers develop close together and form a bisexual floral unit. Pollination takes place either on the upper surface of the water (epihydrophily) or inside gas bubbles underwater (bubble autogamy) - which accounted for about half the seed set in cultivated populations. The pollen does not form stable rafts or “search vehicles”, but spreads as individual grains over the water surface. Pollination at the water surface probably leads to a high degree of outbreeding.
The Guérande salt-pans represent the main French breeding area of bluethroat, a migrating passerine. Salt exploitation has created a geometrical artificial landscape in which we investigated factors influencing spatial distribution and breeding success of this species using a Geographical Information System. We compared data for four sites in these salt-pans, for three zones in the most densely populated site, and for 2500 m2 grid cells defined for this same site. This study showed the influence of (1) the level of salt exploitation activity, (2) the density of bank intersections, (3) the extent of area covered by Suaeda vera bushes and (4) the structural heterogeneity. The continued management of these salt-pans enhanced bird breeding success. Thus, traditional salt exploitation contributes directly to the conservation of bluethroat, considered as an endangered species in Europe.
According to the requirements of the Water Framework Directive 2000/60/EC, all member states of the EU have to establish the typology of their surface waterbodies. The typology is aimed at defining the type-specific reference conditions against which the ecological state of waters can be assessed. The abiotic typology of Polish lakes of an area greater than 50 ha was established based on morphometric, hydrographic and physico-chemical data taken from the Polish national monitoring dataset. The current dataset comprises 749 out of a total of 1042 lakes with an area greater than 50 ha in Poland. Lake types were identified based on a combination of abiotic characteristics of lakes specified in Annex II of the Water Framework Directive such as ecoregions, size, altitude, mean depth, geology and an additional factor – Schindler's ratio. Altogether 13 abiotic lake types were established.
Macroalgae biomass and concentrations of nitrogen, phosphorus and chlorophyll a were determined weekly or biweekly in water and sediments, during the spring-summer of 1985 in a hypertrophic area of the lagoon of Venice. Remarkable biomass production (up to 286 g m−2 day−1, wet weight), was interrupted during three periods of anoxia, when macroalgal decomposition (rate: up to 1000 g m−2 day−1) released extraordinary amounts of nutrients. Depending on the macroalgae distribution in the water column, the nutrients released in water varied from 3·3 to 19·1 μg-at litre−1 for total inorganic nitrogen and from 1·8 to 2·7 μg-at litre−1 for reactive phosphorus. Most nutrients, however, accumulated in the surficial sediment (up to 0·640 and to 3·06 mg g−1 for P and N respectively) redoubling the amounts already stored under aerobic conditions, Phytoplankton, systematically below 5 mg m−3 as Chl. a, sharply increased up to 100 mg m−3 only after the release of nutrients in water by anaerobic macroalgal decomposition. During the algal growth periods, the N:P atomic ratio in water decreased to 0·7, suggesting that nitrogen is a growth-limiting factor. This ratio for surficial sediment was between 6·6 and 13·1, similar to that of macroalgae (8·6–12·0).
The study of impacts of the global climate change in the coastal lagoons, specially in the Mediterranean region, is an important starting point for all the vulnerability studies, risk assessment and management consideration about the mitigation measurements for these areas. The coastal lagoon of Mar Menor has been chosen in order to investigate the response of a transitional environment to A2 IPCC scenario using a numerical tool. A model to reproduce the hydrodynamical processes and the salinity and temperature distribution in the Mar Menor (Spain) was developed. The hydrodynamic model was forced with real wind and water level data (1985–1986) and the results of the simulation were used to calibrate the hydrodynamic model. Simulations of salinity and temperature were carried out in order to validate the model and to reproduce measurements for the year 1997. The model results show a good agreement with data and the model is able to reproduce the salinity and temperature field in the Mar Menor. The climate change simulation was carried out applying the A2 anomalies for 2100 to the 1997 input data set, in order to evaluate the response of the basin in terms of water exchange temperature and salinity variations. The results of the climate change simulation show an increase of the annual mean temperature of 3.28 °C and a decrease of the salinity value of 1.53 PSU.
New data on the ecology of germination of Althenia filiformis Petit. – The author investigated the natural environment where this species, halophyte and hydrophyte, germinates. The relationships between temperature, salt concentration of pools in which Althenia filiformis lives, and the dormancy of seeds were examined. In particular the author studied the behaviour of this species considering the natural conditions of pools of Orbetello (Tuscany) and Simbirizzi (Sardinia).
