Exploring the newly emerging effects of native seagrasses on survival and growth of non-native juvenile clams

The Manila clam (Ruditapes philippinarum) has been introduced into the Atlantic European coast for commercial exploitation. In this region, the population dynamics of this clam species may be determined by the interaction with the native dwarf eelgrass (Zostera noltei). We performed an experiment in the tidal flats of an estuary located in northern Spain to analyse the interaction between Z. noltei and juvenile Manila clams. Based on existing knowledge, it was hypothesised that seagrasses act as a nursery protecting juveniles from predation, which is an important cause of natural mortality, and that seagrass density influences the survival, growth and condition of clams. The results indicate that the effects of seagrasses on juvenile clams depends on shoot density, which mainly determine the relative prevalence of positive versus negative interactions. Dense seagrass meadows protect juvenile clams from predation, likely decreasing their visibility and reducing the efficiency of predators. However, in these dense meadows, a decline in the condition of clams was also observed, although not in shell growth. This decline can be due to the fact that food supply in dense meadows is slow and does not fulfil the replenishment rates required by filter-feeding organisms or because competition for space with the seagrass causes stress. Clams are larger in populations where predator access is prevented, possibly indicating selective predation on larger organisms when this interaction is allowed. The knowledge gained from this experiment is of great interest for analysing possible future trends in clam populations and the derived social implications given its high economic value.This research was part of the ECOTOPO project (RTI2018-096409-B-I00), financially supported by the Spanish Ministry of Science and Innovation through the National Plan for Scientific Research, and the project “Profundizando en el conocimiento de la Biodiversidad en estuarios: el efecto de la escala y la presión en los patrones biológicos funcionales” (56.VP76.64662), financially supported by the regional government through the Consejerı́a de Universidades, Igualdad, Cultura y Deporte del Gobierno de Cantabria (Convocatoria Financiada por el Contrato Programa Gobierno de Cantabria-UC). This study was also supported by the regional government through the Consejería de Desarrollo Rural, Ganadería, Pesca y Alimentación

Nested Socio-Ecological Maps as a Spatial Planning Instrument for Estuary Conservation and Ecosystem-Based Management

ABSTRACT: Estuaries are socio-ecological systems that can be represented as a holistic combination of biotic and abiotic conditions in spatially explicit units defined by: (i) the ecotope, as the integration of the physiotope (abiotic-homogeneous units) and the biotope (biotic-homogeneous units), and (ii) the anthrotope, synthesizing data on human drivers of ecological change. Nested physiotopes were identified in an estuary using a hierarchical approach that integrates information about eight abiotic, and biologically meaningful, variables. The biotope of Zostera noltei was delimited using a potential distribution model of species and overlapped with the physiotope map to characterize the ecotopes. The anthrotope was estimated as the cumulative impacts of anthropic activities over the ecotopes. The diversity of Z. noltei ecotopes was compared with the anthrotope map to estimate the potential impacts of human pressures on this species. The hierarchical methodology and resulting maps provide flexible and interdisciplinary tools for conservation, management, education and research.This research was part of the ECOTOPO project (RTI2018-096409-B-I00) financially supported by the Spanish Ministry of Science and Innovation through the National Plan for Scientific Research

Coastal engineering infrastructure impacts Blue Carbon habitats distribution and ecosystem functions

ABSTRACT: Intertidal estuarine habitats (e.g., saltmarshes and tidal flats) provide important ecosystem services to society, including coastal protection, food provision and Corg sequestration. Yet, estuaries and estuarine habitats have been subjected to intense human pressure, such as land-use change and artificialization of the shoreline to support economic activities and uses. Construction of engineering infrastructures (e.g., piers, bridges) in these areas alters estuary-wide hydromorphological conditions and thus sedimentation patterns at the estuarine scale, which are key drivers of habitats distribution and ecosystem structure, processes and functions. Most of the research on the impact of civil engineering structures on coastal habitats has focused on the biological communities that colonize them or the bottoms where they are placed, whereas their indirect impacts on adjacent habitats has been largely unexplored. Understanding the influence of man-made infrastructures on the distribution of estuarine habitats and functions is critical, particularly considering that shoreline armoring is expected to increase as a way to protect coastal areas from hazards derived from climate change. Shifts in habitat distribution and functions occur in several years or decades and relating them with the occurrence of past historical events is challenging when no monitoring data is available. By examining historical aerial photographs and different biogeochemical properties along a saltmarsh soil record, this study demonstrates that the construction of an infrastructure (i.e. bridge) caused a rapid transformation (~30 years) of a bare sandflat into a high marsh community and to significant changes in sediment biogeochemical properties, including the decrease in sediment accretion rate and Corg burial rates since then. This study contributes to increase the knowledge on the impact that the construction in coastal areas of civil engineering infrastructures can cause in intertidal habitats distribution and the ecological functions they provide for climate change adaption and mitigation.This research was carried out with the contribution of the LIFE Programme of the European Union to the Project ADAPTA BLUES (ref. LIFE18 CCA/ES/001160). This document reflects only the author’s view and the Agency/ Commission is not responsible for any use that may be made of the information it contains. Authors acknowledges the financial support from the Government of Cantabria through the Fénix Programme. The authors want to thank the support of the Generalitat de Catalunya to MERS (2017 SGR-1588) and the Spanish Government for the “Maria de Maeztu” program for Units of Excellence to ICTA (Grant No. CEX2019-000940-M). We would like to thank Joan Manel Bruach Menchen from the Grup de Recerca en Radioactivitat Ambiental de Barcelona—GRAB (Universitat Autònoma de Barcelona) for his work on the analysis of 210Pb dating. In memorial of Jordi Garcia-Orellana, who left us during the preparation of this manuscript, but whose ideas, motivation and help always made this job easy and fun

Exploring the effects of temperature and light availability on the vegetative propagation processes of the non-native species Asparagopsis armata

Widespread generalist species, particularly the non-native invasive ones, are expected to be enhanced by climate change resulting in a biotic homogenization of ecosystems. The red seaweed Asparagopsis armata is a non-native opportunistic species, widely distributed in the European coasts of the North Atlantic, where it has been considered invasive. In this work, we examined the effects of temperature and irradiance on the vegetative propagation process of this species in a laboratory experiment. We considered vegetative propagation due to its implications in the invasion process (as it is considered one of the main sources of recruitment). In gametophytes, the process was characterized through the survival rates of hook-shaped specialized structures and the production and growth of new plantlets from hooks of 1-3cm in length. In tetrasporophytes, the growth and phycobiliprotein contents of previously excised tufts was analyzed. For gametophytes, results revealed how vegetative propagation for this species was conditioned by the low survival rates of hooks once detached from the main thallus. In our experiment, survival probabilities after 30 days of culture were always below 50%. Comparisons among environmental conditions showed lower survival rates under increasing levels of temperature and decreasing levels of irradiance. In fact, mass mortality was detected at 18°C and low irradiance, where almost any hook-shaped fragment survived. Nevertheless, patterns of appearance and growth of plantlets at different temperatures and irradiances were not clear. In the case of tetrasporophytes, only positive growth rates were registered at 15°C and 55-60 mmol/m2/s after 30 days of culture. Higher concentration of phycobiliproteins was detected at higher temperatures during the first days of culture, while not clear patterns were detected at the end. In the light of climate change, understanding these reproduction patterns is necessary in order to adopt better management actions in the future.The author(s) declare financial support was received for the research, authorship, and/or publication of this article. This work was funded by the National Plan for Research in Science and Technological Innovation from the Spanish Government 2017-2020 [grant number C3N-pro project PID2019-105503RB-I00] and co-funded by the European Regional Development’s funds. Samuel Sainz-Villegas and Begoña Sánchez-Astráin acknowledge the financial support received under predoctoral grants from the Spanish Ministry of Science, Innovation and Universities [grant numbers: FPU18/03573 and PRE2020-096255, respectively]. This work is part of the PhD project of Samuel Sainz-Villegas

Predicting non-native seaweeds global distributions: The importance of tuning individual algorithms in ensembles to obtain biologically meaningful results

ABSTRACT: Modelling non-native marine species distributions is still a challenging activity. This study aims to predict the global distribution of five widespread introduced seaweed species by focusing on two mains aspects of the ensemble modeling process: (1) Does the enforcement of less complex models (in terms of number of predictors) help in obtaining better predictions? (2) What are the implications of tuning the configuration of individual algorithms in terms of ecological realism? Regarding the first aspect, two datasets with different number of predictors were created. Regarding the second aspect, four algorithms and three configurations were tested. Models were evaluated using common evaluation metrics (AUC, TSS, Boyce index and TSS-derived sensitivity) and ecological realism. Finally, a stepwise procedure for model selection was applied to build the ensembles. Models trained with the large predictor dataset generally performed better than models trained with the reduced dataset, but with some exceptions. Regarding algorithms and configurations, Random Forest (RF) and Generalized Boosting Models (GBM) scored the highest metric values in average, even though, RF response curves were the most unrealistic and non-smooth and GBM showed overfitting for some species. Generalized Linear Models (GLM) and MAXENT, despite their lower scores, fitted smoother curves (especially at intermediate complexity levels). Reliable and biologically meaningful predictions were achieved. Inspecting the number of predictors to include in final ensembles and the selection of algorithms and its complexity have been demonstrated to be crucial for this purpose. Additionally, we highlight the importance of combining quantitative (based on multiple evaluation metrics) and qualitative (based on ecological realism) methods for selecting optimal configurations.This work was funded by the National Plan for Research in Science and Technological Innovation from the Spanish Government 2017-2020 [grant number C3N-pro project PID2019-105503RB-I00] and co-funded by the European Regional Development’s funds. SS-V acknowledges financial support under a predoctoral grant from the Spanish Ministry of Education andVocational Training [grantnumber:FPU18/03573]. CH acknowledges the financial support from the Government of Cantabria through the Fénix Programme and under a postdoctoral grant from the University of Cantabria [grant number: POS-UC- 2020-07]. This work is part of the PhD project of SS-V

Climate change induced range shifts in seaweeds distributions in Europe

There are evidences of how climate change is affecting seaweeds distribution and the ecosystems services they provide. Therefore, it is necessary to consider these impacts when managing marine areas. One of the most applied tools in recent years to deal with this are species distribution models, however there are still some challenges to solve, such as the inclusion of hydrodynamic predictors and the application of effective, transferable and user-oriented methodologies. Five species (Saccorhiza polyschides, Gelidium spinosum, Sargassum muticum, Pelvetia canaliculata and Cystoseira baccata) in Europe and 15 variables were considered. Nine of them were projected to the RCPs 4.5 and 8.5 for the mid-term (2040?2069) and the long term (2070?2099). Algorithms for each species were applied to generate models that were assessed by comparison of probabilities and observations (area under the curve, true skill statistics, Boyce index, sensitivity, correct classification rate), niches overlap (Schoener's D, Hellinger's I), geographical similarity (interquartile range) and ecological realism. Models built demonstrated very good predictive accuracy and sensitivity, without overfitting risk. A medium overlap in the historical and RCPs environmental conditions were obtained, therefore the models can be considered transferable and results accurate because only some isolated points were detected as outliers, corresponding to low probabilities. The areas of S. polyschides and G. spinosum have been identified to be dramatically reduced, meanwhile S. muticum and C. baccata were predicted to expand their range. P. canaliculata was expected to keep its sites of presence but with a decrease in its probability of occurrence. For all species it was remarkable the importance of hydrodynamic variables and parameters representing extreme conditions. Spatially predictions of the potential species and areas at risk are decisive for defining management strategies and resource allocation. The performance and usefulness of the approach applied in this study have been demonstrated for algae with different ecological requirements (from upper littoral to subtidal) and distributional patterns (native and invasive), therefore results can be used by marine planners with different goals: marine protected areas designation, monitoring efforts guiding, invasions risk assessment or aquaculture facilities zonation.This work was funded by the National Plan for Research in Science and Technological Innovation from the Spanish Government 2013-2016 (Ministry of Economy and Competitiveness) [grant number C3N project CTM2015-68244-R] and co-funded by the European Regional Development's funds (FEDER). Camino Fernández de la Hoz acknowledges financial support under a predoctoral grant from the Spanish Ministry of Econom

OCLE: A European open access database on climate change effects on littoral and oceanic ecosystems

The authors thank NASA, ESA, EMODnet, BODC, NCAR-UCAR and WCRP, which is responsible for CMIP, and the climate modeling groups for producing and making available their model output and data. This work was supported by the National Plan for Research in Science and Technological Innovation from the Spanish Government 2013-2016 (Ministry of Economy and Competitiveness, C3N project) [grant number: CTM2015-68244-R] and cofunded by the European Regional Development's funds (FEDER). Camino F. de la Hoz acknowledges financial support under a predoctoral grant from the Spanish Ministry of Economy, Industry and Competitiveness [grant number: BES-2016-076434

Ecological typologies of large areas. An application in the Mediterranean Sea

One approach to identifying and mapping the state of marine biophysical conditions is the identification of large-scale ecological units for which conditions are similar and the strategies of management may also be similar. Because biological processes are difficult to directly record over large areas, abiotic characteristics are used as surrogate parameters. In this work, the Mediterranean Sea was classified into homogeneous spatial areas based on abiotic variables. Eight parameters were selected based on salinity, sea surface temperature, photosynthetically active radiation, sea-wave heights and depth variables. The parameters were gathered in grid points of 0.5° spatial resolution in the open sea and 0.125° in coastal areas. The typologies were obtained by data mining the eight parameters throughout the Mediterranean and combining two clustering techniques: self-organizing maps and the k-means algorithm. The result is a division of the Mediterranean Sea into seven typologies. For these typologies, the classification recognizes differences in temperature, salinity and radiation. In addition, it separates coastal from deep areas. The influence of river discharges and the entrance of water from other seas are also reflected. These results are consistent with the ecological requirements of the five studied seagrasses (Posidonia oceanica, Zostera marina, Zostera noltei, Cymodocea nodosa, Halophila stipulacea), supporting the suitability of the resulting classification and the proposed methodology. The approach thus provides a tool for the sustainable management of large marine areas and the ability to address not only present threats but also future conditions, such as climate change.This research is included in the framework of the CoCoNET project (Towards COast to COast NETworks of marine protected areas (from the shore to the high and deep sea), coupled with sea-based wind energy potential) and is funded by the National Plan for Research in Science and Technological Innovation from the Spanish Government 2013–2016 (Ministry of Economy and Competitiveness) (C3N project CTM2015-68244-R) and co-financed by the European Regional Development's funds (FEDER). Melisa Menéndez acknowledges financial support from the Ramon y Cajal Program (RYC-2014-16469). Camino F. de la Hoz acknowledges financial support in the form of a predoctoral grant (Ref: BES-2016-076434) from the Spanish Ministry of Economy, Industry and Competitiveness. We also thank the anonymous reviewers for their comments and suggestion