Ocean Acidification Outweighs Nutrient Effects in Structuring Seagrass Epiphyte Communities

Developing a framework for assessing interactions between multiple anthropogenic stressors remains an important goal in environmental research. In coastal ecosystems, the relative effects of aspects of global climate change (e.g. CO2 concentrations) and localized stressors (e.g. eutrophication), in combination, have received limited attention. Using a long-term (11 month) field experiment, we examine how epiphyte assemblages in a tropical seagrass meadow respond to factorial manipulations of dissolved carbon dioxide (CO2(aq)) and nutrient enrichment. In situ CO2(aq) manipulations were conducted using clear, open-top chambers, which replicated carbonate parameter forecasts for the year 2100. Nutrient enrichment consisted of monthly additions of slow-release fertilizer, nitrogen (N) and phosphorus (P), to the sediments at rates equivalent to theoretical maximum rates of anthropogenic loading within the region (1.54 g N m−2 d−1 and 0.24 g P m−2 d−1). Epiphyte community structure was assessed on a seasonal basis and revealed declines in the abundance of coralline algae, along with increases in filamentous algae under elevated CO2(aq). Surprisingly, nutrient enrichment had no effect on epiphyte community structure or overall epiphyte loading. Interactions between CO2(aq) and nutrient enrichment were not detected. Furthermore, CO2(aq)-mediated responses in the epiphyte community displayed strong seasonality, suggesting that climate change studies in variable environments should be conducted over extended time-scales. Synthesis. The observed responses indicate that for certain locations, global stressors such as ocean acidification may take precedence over local eutrophication in altering the community structure of seagrass epiphyte assemblages. Given that nutrient-driven algal overgrowth is commonly cited as a widespread cause of seagrass decline, our findings highlight that alternate climate change forces may exert proximate control over epiphyte community structure.

Effects of in situ CO2 enrichment on structural characteristics, photosynthesis, and growth of the Mediterranean seagrass Posidonia oceanica

Seagrass is expected to benefit from increased carbon availability under future ocean acidification. This hypothesis has been little tested by in situ manipulation. To test for ocean acidification effects on seagrass meadows under controlled CO2/pH conditions, we used a Free Ocean Carbon Dioxide Enrichment (FOCE) system which allows for the manipulation of pH as continuous offset from ambient. It was deployed in a Posidonia oceanica meadow at 11 m depth in the Northwestern Mediterranean Sea. It consisted of two benthic enclosures, an experimental and a control unit both 1.7 m**3, and an additional reference plot in the ambient environment (2 m**2) to account for structural artifacts. The meadow was monitored from April to November 2014. The pH of the experimental enclosure was lowered by 0.26 pH units for the second half of the 8-month study. The greatest magnitude of change in P. oceanica leaf biometrics, photosynthesis, and leaf growth accompanied seasonal changes recorded in the environment and values were similar between the two enclosures. Leaf thickness may change in response to lower pH but this requires further testing. Results are congruent with other short-term and natural studies that have investigated the response of P. oceanica over a wide range of pH. They suggest any benefit from ocean acidification, over the next century (at a pH of 7.7 on the total scale), on Posidonia physiology and growth may be minimal and difficult to detect without increased replication or longer experimental duration. The limited stimulation, which did not surpass any enclosure or seasonal effect, casts doubts on speculations that elevated CO2 would confer resistance to thermal stress and increase the buffering capacity of meadows.

Seawater carbonate chemistry, structural and chemical characteristics of the seagrass Thalassia testudinum in an situ CO2 enrichment experiment

Seagrasses commonly display carbon-limited photosynthetic rates. Thus, increases in atmospheric pCO2, and consequentially oceanic CO2(aq) concentrations, may prove beneficial. While addressed in mesocosms, these hypotheses have not been tested in the field with manipulative experimentation. This study examines the effects of in situ CO2(aq) enrichment on the structural and chemical characteristics of the tropical seagrass, Thalassia testudinum. CO2(aq) availability was manipulated for 6 months in clear, open-top chambers within a shallow seagrass meadow in the Florida Keys (USA), reproducing forecasts for the year 2100. Structural characteristics (leaf area, leaf growth, shoot mass, and shoot density) were unresponsive to CO2(aq) enrichment. However, leaf nitrogen and phosphorus content declined on average by 11 and 21 %, respectively. Belowground, non-structural carbohydrates increased by 29 %. These results indicate that increased CO2(aq) availability may primarily alter the chemical composition of seagrasses, influencing both the nutrient status and resilience of these systems.

Tree characteristics, biomass and vegetation cover near Abisko Research Station in 1997 and 2010

This study was conducted in the Swedish sub-Arctic, near Abisko, in order to assess the direction and scale of possible vegetation changes in the alpine-birch forest ecotone. We have re-surveyed shrub, tree and vegetation data at 549 plots grouped into 61 clusters. The plots were originally surveyed in 1997 and re-surveyed in 2010. Our study is unique for the area as we have quantitatively estimated a 19% increase in tree biomass mainly within the existing birch forest. We also found significant increases in the cover of two vegetation types - "birch forest-heath with mosses" and "meadow with low herbs", while the cover of snowbed vegetation decreased significantly. The vegetation changes might be caused by climate, herbivory and past human impact but irrespective of the causes, the observed transition of the vegetation will have substantial effects on the mountain ecosystems.

Algunas consideraciones acerca de la presencia de Homero en la obra de Unamuno

Miguel de Unamuno fue un constante lector de poesía épica, en la que Homero siempre tuvo un lugar preferente, y no solo por motivos profesionales. A lo largo de su obra, tanto en prosa como en verso, pueden rastrearse distintas y a veces contradictorias referencias a la Ilíada y la Odisea sobre las que hizo profundas reflexiones, intentando siempre ajustarlas a su propia visión de la vida y de la muerte. Desde esta perspectiva se acerca a escenarios como el ‘prado de asfódelos’, o, a partir del símil homérico, al ‘sucederse de las generaciones de las hojas y de los hombres’, o a figuras míticas como las Sirenas, Helena, Tántalo, Sísifo y Ulises.

Satisfação com a Vida e com o Lar

O envelhecimento da população é uma realidade indiscutível nas sociedades contemporâneas. Independentemente dos modelos societários em que vivamos, a longevidade só faz sentido se for acompanhada por felicidade, qualidade e satisfação de vida. No entanto, este envelhecimento generalizado da população traz consigo vários constrangimentos à população idosa, entre eles a sua institucionalização em lares de terceira idade. O processo de institucionalização pode ter efeitos negativos ao nível do bemestar psicossocial dos idosos institucionalizados se não forem tidos em conta determinados factores promotores do sucesso adaptativo que conduzam a melhores níveis de satisfação. Neste estudo, a questão lançada tem subjacente a convicção de que existem vários factores que podem contribuir ou influenciar positiva ou negativamente a satisfação com o lar das pessoas idosas residentes em cenários institucionais. Este foi, precisamente, o objectivo do nosso trabalho, ou seja, analisar os níveis de satisfação com a vida e com o lar e os factores que se relacionam com a satisfação com o lar. Trata-se de um estudo de observação, transversal, que recaiu em 49 idosos institucionalizados em duas instituições da rede solidária do concelho de Miranda do Corvo. Utilizámos uma metodologia quantitativa para medir objectivamente o nível de satisfação com a vida e com o lar das pessoas idosas institucionalizadas. No âmbito da utilização desta metodologia administrou-se um inquérito por questionário, elaborado por nós, e uma Escala de Satisfação com a Vida (Meadow et. al., 1992). A aplicação desta Escala de Satisfação com a Vida revelou boas características psicométricas ao nível da fidedignidade (medida através da sua consistência interna) e a média reflecte um grupo de inquiridos moderadamente satisfeitos com a vida. Na nossa investigação empírica tivemos oportunidade de verificar que a maior parte dos inquiridos se manifestou satisfeita com a sua residência no lar. Apurámos igualmente que existe uma associação entre a satisfação com o lar e a solidão e que a satisfação difere consoante os contactos de amizade (presença versus ausência) e as actividades sóciorecreativas (participação versus não participação).

Food for Pollinators: Quantifying the Nectar and Pollen Resources of Urban Flower Meadows

Planted meadows are increasingly used to improve the biodiversity and aesthetic amenity value of urban areas. Although many ‘pollinator-friendly’ seed mixes are available, the floral resources these provide to flower-visiting insects, and how these change through time, are largely unknown. Such data are necessary to compare the resources provided by alternative meadow seed mixes to each other and to other flowering habitats. We used quantitative surveys of over 2 million flowers to estimate the nectar and pollen resources offered by two exemplar commercial seed mixes (one annual, one perennial) and associated weeds grown as 300m2 meadows across four UK cities, sampled at six time points between May and September 2013. Nectar sugar and pollen rewards per flower varied widely across 65 species surveyed, with native British weed species (including dandelion, Taraxacum agg.) contributing the top five nectar producers and two of the top ten pollen producers. Seed mix species yielding the highest rewards per flower included Leontodon hispidus, Centaurea cyanus and C. nigra for nectar, and Papaver rhoeas, Eschscholzia californica and Malva moschata for pollen. Perennial meadows produced up to 20x more nectar and up to 6x more pollen than annual meadows, which in turn produced far more than amenity grassland controls. Perennial meadows produced resources earlier in the year than annual meadows, but both seed mixes delivered very low resource levels early in the year and these were provided almost entirely by native weeds. Pollen volume per flower is well predicted statistically by floral morphology, and nectar sugar mass and pollen volume per unit area are correlated with flower counts, raising the possibility that resource levels can be estimated for species or habitats where they cannot be measured directly. Our approach does not incorporate resource quality information (for example, pollen protein or essential amino acid content), but can easily do so when suitable data exist. Our approach should inform the design of new seed mixes to ensure continuity in floral resource availability throughout the year, and to identify suitable species to fill resource gaps in established mixes.

Macroinvertebrate Diversity in Urban and Rural Ponds: Implications for Freshwater Biodiversity Conservation

Ponds are among the most biodiverse freshwater ecosystems, yet face significant threats from removal, habitat degradation and a lack of legislative protection globally. Information regarding the habitat quality and biodiversity of ponds across a range of land uses is vital for the long term conservation and management of ecological resources. In this study we examine the biodiversity and conservation value of macroinvertebrates from 91 lowland ponds across 3 land use types (35 floodplain meadow, 15 arable and 41 urban ponds). A total of 224 macroinvertebrate taxa were recorded across all ponds, with urban ponds and floodplain ponds supporting a greater richness than arable ponds at the landscape scale. However, at the alpha scale, urban ponds supported lower faunal diversity (mean: 22 taxa) than floodplain (mean: 32 taxa) or arable ponds (mean: 30 taxa). Floodplain ponds were found to support taxonomically distinct communities compared to arable and urban ponds. A total of 13 macroinvertebrate taxa with a national conservation designation were recorded across the study area and 12 ponds (11 floodplain and 1 arable pond) supported assemblages of high or very high conservation value. Pond conservation currently relies on the designation of individual ponds based on very high biodiversity or the presence of taxa with specific conservation designations. However, this site specific approach fails to acknowledge the contribution of ponds to freshwater biodiversity at the landscape scale. Ponds are highly appropriate sites outside of protected areas (urban/arable), with which the general public are already familiar, for local and landscape scale conservation of freshwater habitats.

Modellierung und Validierung des landwirtschaftlichen Ertrages der Grünlandflächen Südtirols

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Fluviatile und äolische Prozesse im Gebiet der unteren Elbe bei Neuhaus (Niedersachsen) seit dem Weichselspätglazial

The Late Glacial and Holocene landscape development in the vicinity of the River Elbe near Neuhaus, Lower Saxony, was studied during geological mapping of the area. The geological and geobotanical methods used in these investigations were chosen to cope with the difficulties which arise during research on Quaternary flood plains in low country. Paleochannel fill and areas of flood-plain sediments were drilled, the lithology examined, and the sediments dated on the basis of their pollen content. No evidence was found for the existence before the Middle Ages of paleo- channels the size of the present River Elbe. Before the first measures were made to regulate the Elbe River, it was an anastomosing river system with numerous small branches. The lower parts of the flood-plain profiles are predominantly sand and the upper parts silty-clayey loam. With the construction of effective levees over the last several centuries, the flow velocity of the Elbe has increased considerably during high water periods and instead of the deposition of meadow loam, sand was deposited as natural levees. The main belt of sand dunes on the east bank of the Elbe overlies Preboreal to Boreal lake mud and is, therefore, of Holocene age.

Biodiversité des pollinisateurs dans les cannebergières : effets des pratiques culturales, du type de sol et de l'habitat naturel

Les pollinisateurs indigènes sont importants pour la production de canneberges. Ils sont pourtant menacés par les pratiques agricoles qui s’intensifient. Pour établir un plan de conservation efficace, une meilleure connaissance des facteurs intrinsèques aux exploitations est essentielle. L’objectif principal de cette étude était de déterminer la diversité et abondance des abeilles et syrphes retrouvées en cannebergières. Quinze fermes ont été échantillonnées selon la régie de culture, le type de sol et le type d’habitat naturel retrouvé près des cannebergières. Des pièges-bols disposés en transect ainsi que l’utilisation de filet entomologique ont été utilisés pour échantillonner les pollinisateurs. Au total, 135 espèces de pollinisateurs indigènes ont été capturées en 2013 et 2014. Le type de sol ainsi que l’habitat naturel influençaient les communautés de pollinisateurs, alors que la régie de culture ne les affectait pas. L’abeille Melitta americana, spécialiste du pollen de canneberge, a été capturée plus souvent dans les tourbières.

Restoration ecology of coastal lagoons: new methods for the prediction of ecological trajectories and economic valuation

Conservation of the seven lagoons of the Palavas complex (southern France) has been severely impaired by nutrient over-enrichment during at least four decades. The effluents of the Montpellier wastewater treatment plant (WWTP) represented the main nutrient input. To improve the water quality of these lagoons, this WWTP was renovated and upgraded and, since the end of 2005, its effluents have been discharged 11 km offshore into the Mediterranean (total investment €150 M). Possibilities of ecosystem restoration as part of a conservation programme were explored by a focus group of experts. Their tasks were: (i) to evaluate the impact of the reduction of the nutrient input; (ii) if necessary, to design additional measures for an active restoration programme; and (iii) to predict ecosystem trajectories for the different cases. Extension of Magnoliophyta meadows can be taken as a proxy for ecosystem restoration as they favour the increase of several fish (seahorse) and bird (ducks, swans, herons) species, albeit they represent a trade-off for greater flamingos. Additional measures for active ecosystem restoration were only recommended for the most impaired lagoon Méjean, while the least impaired lagoon Ingril is already on a trajectory of spontaneous recovery. A multiple contingent valuation considering four different management options for the Méjean lagoon was used in a pilot study based on face-to-face interviews with 159 respondents. Three levels of ecosystem restoration were expressed in terms of recovery of Magnoliophyta meadows, including their impact on emblematic fish and avifauna. These were combined with different options for access (status quo, increasing access, increasing access with measures to reduce disturbance). The results show a willingness of local populations to pay per year about €25 for the highest level of ecological restoration, while they were only willing to allocate about €5 for additional footpaths and hides.

Evolución del paisaje y aprovechamientos económicos en la falda de la sierra cordobesa (Siglos XIII-XV)

La falda de la sierra cordobesa forma un espacio unitario íntimamente conectado geográfica, emocional y económicamente con la ciudad. En este espacio se sitúan elementos históricos tan importantes como el heredamiento de la Albaida o, sobre todo, la dehesa de Córdoba la Vieja, que recibe este nombre por encontrarse en su interior las ruinas de la antigua ciudad omeya de Madinat al-Zahra. Tradicionalmente se ha presentado este espacio como una amplia dehesa dedicada a la ganadería extensiva. Sin embargo, un estudio más detallado de las fuentes documentales disponibles nos muestra un paisaje diversificado en el que, junto con los pastos para el ganado, abundan olivares, viñas y huertas que fueron fundamentales para el abastecimiento de los mercados de la ciudad de Córdoba durante la Baja Edad Media.

Large-scale prediction of seagrass distribution: the case of Cymodocea nodosa (Mediterranean-Atlantic)

Understanding the factors that affect seagrass meadows encompassing their entire range of distribution is challenging yet important for their conservation. We model the environmental niche of Cymodocea nodosa using a combination of environmental variables and landscape metrics to examine factors defining its distribution and find suitable habitats for the species. The most relevant environmental variables defining the distribution of C. nodosa were sea surface temperature (SST) and salinity. We found suitable habitats at SST from 5.8 ºC to 26.4 ºC and salinity ranging from 17.5 to 39.3. Optimal values of mean winter wave height ranged between 1.2 m and 1.5 m, while waves higher than 2.5 m seemed to limit the presence of the species. The influence of nutrients and pH, despite having weight on the models, was not so clear in terms of ranges that confine the distribution of the species. Landscape metrics able to capture variation in the coastline enhanced significantly the accuracy of the models, despite the limitations caused by the scale of the study. By contrasting predictive approaches, we defined the variables affecting the distributional areas that seem unsuitable for C. nodosa as well as those suitable habitats not occupied by the species. These findings are encouraging for its use in future studies on climate-related marine range shifts and meadow restoration projects of these fragile ecosystems.