Rita Araújo

Checklist of benthic marine algae and cyanobacteria of northern Portugal

The northern Portuguese coast is a biogeographic transition zone where many macroalgal species have their distribution limits; it is thus a particularly interesting region for investigating species distribution shifts. An updated and complete list of species for this region is not available in spite of its baseline importance for comparative studies with past and present data. Based on new records, literature references, and herbarium data, we provide an updated checklist of the benthic marine algae of the northern Portuguese coast. This checklist includes 346 species: 26 Cyanobacteria, 200 Rhodophyta, 70 Ochrophyta, and 50 Chlorophyta. From these, 21 species are new records for the Portuguese coast (Lyngbya aestuarii, Lyngbya semiplena, Microcoleus acutirostris, Myxosarcina gloeocapsoides, Aiolocolax pulchella, Antithamnion densum, Antithamnion villosum, Antithamnionella spirographidis, Dasya sessilis, Furcellaria lumbricalis, Neosiphonia harveyi, Porphyrostromium boryanum, Chorda filum, Dictyopteris ambigua, Sphacelaria rigidula, Undaria pinnatifida, Vaucheria coronata, Vaucheria velutina, Ulothrix implexa, Ulva scandinavica, and Umbraulva olivascens) and 33 were recorded for the first time in the north of Portugal. Alien species have increased in number and extended their distribution range over the last 10 years in the study area. Distribution shifts of northern cold water species with southern distribution limit in the north of Portugal were not consistent among species.

PHENOTYPIC DIFFERENTIATION AT SOUTHERN LIMIT BORDERS: THE CASE STUDY OF TWO FUCOID MACROALGAL SPECIES WITH DIFFERENT LIFE-HISTORY TRAITS1

Marginal populations are often geographically isolated, smaller, and more fragmented than central populations and may frequently have to face suboptimal local environmental conditions. Persistence of these populations frequently involves the development of adaptive traits at phenotypic and genetic levels. We compared population structure and demographic variables in two fucoid macroalgal species contrasting in patterns of genetic diversity and phenotypic plasticity at their southern distribution limit with a more central location. Models were Ascophyllum nodosum (L.) Le Jol. (whose extreme longevity and generation overlap may buffer genetic loss by drift) and Fucus serratus L. (with low genetic diversity at southern margins). At edge locations, both species exhibited trends in life‐history traits compatible with population persistence but by using different mechanisms. Marginal populations of A. nodosum had higher reproductive output in spite of similar mortality rates at all life stages, making edge populations denser and with smaller individuals. In F. serratus, rather than demographic changes, marginal populations differed in habitat, occurring restricted to a narrower vertical habitat range. We conclude that persistence of both A. nodosum and F. serratus at the southern‐edge locations depends on different strategies. Marginal population persistence in A. nodosum relies on a differentiation in life‐history traits, whereas F. serratus, putatively poorer in evolvability potential, is restricted to a narrower vertical range at border locations. These results contribute to the general understanding of mechanisms that lead to population persistence at distributional limits and to predict population resilience under a scenario of environmental change.

Data integration for European marine biodiversity research: creating a database on benthos and plankton to study large-scale patterns and long-term changes.

The general aim of setting up a central database on benthos and plankton was to integrate long-, medium- and short-term datasets on marine biodiversity. Such a database makes it possible to analyse species assemblages and their changes on spatial and temporal scales across Europe. Data collation lasted from early 2007 until August 2008, during which 67 datasets were collected covering three divergent habitats (rocky shores, soft bottoms and the pelagic environment). The database contains a total of 4,525 distinct taxa, 17,117 unique sampling locations and over 45,500 collected samples, representing almost 542,000 distribution records. The database geographically covers the North Sea (221,452 distribution records), the North-East Atlantic (98,796 distribution records) and furthermore the Baltic Sea, the Arctic and the Mediterranean. Data from 1858 to 2008 are presented in the database, with the longest time-series from the Baltic Sea soft bottom benthos. Each delivered dataset was subjected to certain quality control procedures, especially on the level of taxonomy. The standardisation procedure enables pan-European analyses without the hazard of taxonomic artefacts resulting from different determination skills. A case study on rocky shore and pelagic data in different geographical regions shows a general overestimation of biodiversity when making use of data before quality control compared to the same estimations after quality control. These results prove that the contribution of a misspelled name or the use of an obsolete synonym is comparable to the introduction of a rare species, having adverse effects on further diversity calculations. The quality checked data source is now ready to test geographical and temporal hypotheses on a large scale.

A Spectroscopic Study of Brazilwood Paints in Medieval Books of Hours

In this work, microspectrofluorimetry was for the first time applied to the identification of the red organic lakes that are characteristic of the lavish illuminations found in 15th century books of hours. Microspectrofluorimetry identified those red paints, ranging from opaque pink to dark red glazes, as brazilwood lakes. An unequivocal characterization was achieved by comparison with reference paints produced following recipes from the medieval treatise The Book on How to Make Colours, and was further confirmed by fiber optic reflectance spectroscopy (FORS). For these treasured cultural objects, microspectrofluorimetry and FORS proved to be the only techniques that could identify, in situ or in microsamples, the chromophore responsible for the pinkish hues: a brazilein-Al3+ complex. Additionally, a multi-analytical approach provided a full characterization of the color paints, including pigments, additives, and binders. Microspectroscopic techniques, based on infrared and X-ray radiation, enabled us to disclose the full palette of these medieval manuscripts, including the elusive greens, for which, besides malachite, basic copper sulfates were found; Raman microscopy suggested a mixture of brochantite and langite. Infrared analysis proved invaluable for a full characterization of the additives that were applied as fillers or whites (chalk, gypsum, and white lead) as well as the proteinaceous and polysaccharide binders that were found pure or in mixture.

Biomonitoring of pesticides by pine needles — Chemical scoring, risk of exposure, levels and trends

Vegetation is a useful matrix for the quantification of atmospheric pollutants such as semi-volatile organic compounds (SVOCs). In particular, pine needles stand out as effective biomonitors due to the excellent uptake properties of their waxy layer. Having previously validated an original and reliable method to analyse pesticides in pine needles, our work team set the objective of this study to determine the levels of 18 pesticides in Pinus pinea needles collected in 12 different sampling sites in Portugal. These compounds were selected among a total of 70 pesticides by previous chemical scoring, developed to assess their probability to occur in the atmosphere. The risk of exposure was evaluated by the binomial chemical score/frequency of occurrence in the analysed samples. Levels and trends of the chemical families and target of the pesticides were obtained regarding the type of land occupation of the selected sites, including the use of advanced statistics (principal component analysis, PCA). Finally, some correlations with several characteristics of the sampling sites (population, energy consumption, meteorology, etc.) were also investigated.

Status, trends and drivers of kelp forests in Europe: an expert assessment

A comprehensive expert consultation was conducted in order to assess the status, trends and the most important drivers of change in the abundance and geographical distribution of kelp forests in European waters. This consultation included an on-line questionnaire, results from a workshop and data provided by a selected group of experts working on kelp forest mapping and eco-evolutionary research. Differences in status and trends according to geographical areas, species identity and small-scale variations within the same habitat where shown by assembling and mapping kelp distribution and trend data. Significant data gaps for some geographical regions, like the Mediterranean and the southern Iberian Peninsula, were also identified. The data used for this study confirmed a general trend with decreasing abundance of some native kelp species at their southern distributional range limits and increasing abundance in other parts of their distribution (Saccharina latissima and Saccorhiza polyschides). The expansion of the introduced species Undaria pinnatifida was also registered. Drivers of observed changes in kelp forests distribution and abundance were assessed using experts’ opinions. Multiple possible drivers were identified, including global warming, sea urchin grazing, harvesting, pollution and fishing pressure, and their impact varied between geographical areas. Overall, the results highlight major threats for these ecosystems but also opportunities for conservation. Major requirements to ensure adequate protection of coastal kelp ecosystems along European coastlines are discussed, based on the local to regional gaps detected in the study.

Distribution and population dynamics of the introduced seaweed Grateloupia turuturu (Halymeniaceae, Rhodophyta) along the Portuguese coast

Araújo R., Violante J., Pereira R., Abreu H., Arenas F. and Sousa-Pinto I. 2011. Distribution and population dynamics of the introduced seaweed Grateloupia turuturu (Halymeniaceae, Rhodophyta) along the Portuguese coast. Phycologia 50: 392–402. DOI: 10.2216/10-65.1 Despite the increasing number of coastal areas invaded over the last years by the introduced seaweed Grateloupia turuturu, studies on this species are scarce worldwide, and its invasive capability and future impacts remain unexplored. In the present study, we describe the geographical distribution of the species after a few years of colonization of the Portuguese continental coastline. Additionally, we examine the structure and dynamics of one of the first population of Grateloupia in our shores. Seasonal dynamics of standing biomass, density, size structure and inequality (size variability), together with the presence of fertile fronds were investigated during one year. Grateloupia was recorded in midintertidal pools at 11 of the 36 localities sampled, two of which presenting an elevated abundance of fronds. Fronds were present during the entire year, but their size (length and biomass), density and size inequality varied seasonally reaching highest values at the beginning of the summer. The annual cycle of the population studied included a slow-growth phase in winter, a fast-growth phase during spring-early summer when some density-dependent regulation appeared to occur, as well as a dieback phase at the end of summer. In terms of fertility, abundance of fronds bearing reproductive structures were seasonally variable although carposporophytic and tetrasporophytic fronds were recorded throughout the year. The results of this work highlight some of the biological characteristics of Grateloupia turuturu that may determine its invasive nature and its possible impact on native ecosystems.

Spatial and Temporal Dynamics of Fucoid Populations (Ascophyllum nodosum and Fucus serratus): A Comparison between Central and Range Edge Populations

Persistence of populations at range edges relies on local population dynamics and fitness, in the case of geographically isolated populations of species with low dispersal potential. Focusing on spatial variations in demography helps to predict the long-term capability for persistence of populations across the geographical range of species’ distribution. The demography of two ecological and phylogenetically close macroalgal species with different life history characteristics was investigated by using stochastic, stage-based matrix models. Populations of Ascophyllum nodosum and Fucus serratus were sampled for up to 4 years at central locations in France and at their southern range limits in Portugal. The stochastic population growth rate (λs) of A. nodosum was lower and more variable in central than in southern sites whilst for F. serratus this trend was reversed with λs much lower and more variable in southern than in central populations. Individuals were larger in central than in southern populations for both species, which was reflected in the lower transition probabilities of individuals to larger size classes and higher probability of shrinkage in the southern populations. In both central and southern populations elasticity analysis (proportional sensitivity) of population growth rate showed that fertility elements had a small contribution to λs that was more sensitive to changes in matrix transitions corresponding to survival. The highest elasticities were found for loop transitions in A. nodosum and for growth to larger size classes in F. serratus. Sensitivity analysis showed high selective pressure on individual growth for both species at both locations. The results of this study highlight the deterministic role of species-specific life-history traits in population demography across the geographical range of species. Additionally, this study demonstrates that individuals’ life-transitions differ in vulnerability to environmental variability and shows the importance of vegetative compared to reproductive stages for the long-term persistence of populations.

The network BiodiversityKnowledge in practice: insights from three trial assessments

Abstract In order to develop BiodiversityKnowledge, a Network of Knowledge working at the European science–policy interface for biodiversity and ecosystem services, we conducted three trial assessments. Their purpose was to test structure and processes of the knowledge synthesis function and to produce knowledge syntheses. The trial assessments covered conservation and management of kelp ecosystems, biological control of agricultural pests, and conservation and multifunctional management of floodplains. Following the BiodiversityKnowledge processes, we set up expert consultations, systematic reviews, and collaborative adaptive management procedures in collaboration with requesters, policy and decision-makers, stakeholders, and knowledge holders. Outputs included expert consultations, systematic review protocols, a group model and a policy brief. Important lessons learned were firstly that the scoping process, in which requesters and experts iteratively negotiate the scope, scale and synthesis methodology, is of paramount importance to maximize the scientific credibility and policy relevance of the output. Secondly, selection of a broad array of experts with diverse and complementary skills (including multidisciplinary background and a broad geographical coverage) and participation of all relevant stakeholders is crucial to ensure an adequate breath of expertise, better methodological choices, and maximal uptake of outcomes: Thirdly, as the most important challenge was expert and stakeholder engagement, a high visibility and reputation of BiodiversityKnowledge, supported by an incentive system for participation, will be crucial to ensure such engagement. We conclude that BiodiversityKnowledge has potential for a good performance in delivering assessments, but it requires adequate funding, trust-building among knowledge holders and stakeholders, and a proactive and robust interface with the policy and decision making community.

Trade-offs between life-history traits at range-edge and central locations

The allocation of resources to different life‐history traits should represent the best compromise in fitness investment for organisms in their local environment. When resources are limiting, the investment in a specific trait must carry a cost that is expressed in trade‐offs with other traits. In this study, the relative investment in the fitness‐related traits, growth, reproduction and defence were compared at central and range‐edge locations, using the seaweed Ascophyllum nodosum as a model system. Individual growth rates were similar at both sites, whereas edge populations showed a higher relative investment in reproduction (demonstrated by a higher reproductive allocation and extended reproductive periods) when compared to central populations that invested more in defence. These results show the capability of A. nodosum to differentially allocate resources for different traits under different habitat conditions, suggesting that reproduction and defence have different fitness values under the specific living conditions experienced at edge and central locations. However, ongoing climate change may threaten edge populations by increasing the selective pressure on specific traits, forcing these populations to lower the investment in other traits that are also potentially important for population fitness.