1,721,046 research outputs found
Stima della produttività di Vitis vinifera L., tramite un modello big-leaf
No full textIn order to assess primary productivity and transpiration of plant communities
several approaches are used. Here a modification of the model
developed by Vitale et al., based on the ‘big leaf’ approach, has
been used to model functional behaviour of Vitis vinifera L. Model
inputs are: latitude; mean temperature on monthly basis; maximum
photosynthesis rate; Quantum Yield as a temperature function; leaf
angle; reference temperature for respiration. Field gas-exchange measurements
were carried out at leaf level and it was necessary to make
some assumptions on canopy structure in order to avoid overestimation
of biomass production. These assumptions are required since canopies
structure in known to influence productivity and to determine
canopy conductance. The model estimates a crop net production of
186 g dry weight/m2, in accordance with field data. The model also
highlights the relationship between biomass production and canopy
structure in accordance with those productivity models based on
allometric relationship
Photosynthetic traits as indicators for phenotyping urban and peri-urban forests. A case study in the metropolitan city of Rome
No full textPhenotyping for functional traits associated with photosynthetic machinery could be a promising approach for studying the performance of green infrastructures in metropolitan areas. Trait-based indicators hold important information about ecosystem processes and how environmental constrains may influence the provisioning of services. This work aims to apply a high-throughput phenotyping approach to an urban and a peri-urban forest, in order to evaluate the functionality of vegetation through direct measures of photosynthetic traits such as spectroscopy indices, chlorophyll a fluorescence (ChlF) and leaf chemistry (nitrogen and carbon content). Quercus ilex L. was chosen as the target species for its wide distribution in natural and urban greening, sampled at two distances from a high traffic road (urban forest) and in a natural preserved area (peri-urban forest). The reflectance index most related to the general functionality of photosynthetic machinery was the Fluorescence Ratio Indices FRI 740/800 , whereas the highest informative indicator traits to differentiate the functionality of Q. ilex in different periods of the year in the urban and peri-urban forest were Normalized Difference Vegetation Index (NDVI), Structure-Insensitive Pigment Index (SIPI) and Normalized Difference Nitrogen Index (NDNI). Interestingly, Photochemical Reflectance Index (PRI) was not only correlated to functional parameters connected to PSII light absorption side, but also with ChlF parameters related to carbon assimilation such as regeneration capacity of the end acceptors. ChlF parameters are effective indicators for highlighting differences between sites, pointing out that the urban forest sites have lower functionality compared to peri-urban one
Combination effect of sea spray and ozone on gas exchange parameters and fluorescence O-J-I-P transients in mediterranean maquis species
No full textCOMBINATION EFFECT OF SEA SPRAY AND OZONE ON GAS EXCHANGE PARAMETERS AND FLUORESCENCE O-J-I-P TRANSIENTS IN MEDITERRANEAN MAQUIS SPECIE
Contrasting physiological responses of Mediterranean maquis species to sea spray and ozone interaction
No full textContrasting physiological responses of Mediterranean maquis species to sea spray and ozone interactio
Environmental filtering drives community specific leaf area in Spanish forests and predicts relevant changes under future climatic conditions
No full textHow functional traits at community level relate with environmental conditions is of great relevance to assess potential effects of climate change on ecosystem functioning. Speciesâ specific leaf area (SLA) is well recognised to be closely correlated with species drought resistance and with other forest functions such as productivity. Here, we used tree species abundance data from 44 501 forest plots from the Third Spanish National Forest Inventory and species SLA values from literature to assess how community weighted mean SLA (CWMSLA) and SLA diversity within communities (FDisSLA) of Spanish forests correlate with aridity. Later, using 19 climate change projections and following an approach that limits the values of CWMSLAalong an aridity gradient, we assessed the potential climatic effects on CWMSLAfor 2050 under the representative concentration pathways (RCP) 4.5 and 8.5. Results showed that CWMSLAand FDisSLAdecreased significantly with aridity (deviance explained was 22 and 9%, respectively) suggesting an effect of climatic filtering at community level constraining the diversity of co-occurring strategies at harsher conditions. Up to 25% of plots were predicted to suffer changes in CWMSLAwith these impacts being more common and of a greater magnitude in communities characterised by a high CWMSLAand located at humid and mid-altitude zones. Instead, communities already striving in arid areas appeared to be more resilient. The study proves useful for orienting forest management practices in current permanent forest stands based on trait ecology (e.g. promoting communities species composition with specific trait values), to increase their mitigation potential and adaptive capacity to current and future changing climate conditions
Reflectance measurements at climate change experiment sites in Europe
No full textINCREASE infrastructures (EU 7th FP) provide access for visiting scientists to study the effects of long-term climate manipulation treatments in field experiments on shrubland ecosystems across Europe. Climate manipulations include prolonged drought and warming treatments which have lasted for over 10 years, and free-air increased CO2 treatment in Denmark, Brandbjerg running over 5 years. Non-invasive measurement techniques are particularly encouraged for minimizing the disturbance on experimental plots. We visited the experimental sites in Italy (Porto Conte) and Denmark (Mols and Brandbjerg) in summer 2011 to conduct reflectance measurements in visible and short-wave infrared spectral region (400-2500 nm).</p
Urban and peri-urban forests in the metropolitan area of Rome. Ecophysiological response of Quercus ilex L. in two green infrastructures in an ecosystem services perspective
No full textGreen infrastructures (GI), such as urban forests, deliver ecosystem services (ESs) and benefits. AmongESs the amelioration of urban air quality through the removal of air pollutants deserves large attentionowing to the positive impact on human well-being. Experimental data, as detailed descriptions of func-tional parameters, are needed for reliable quantification of ESs. The present study was carried out in themetropolitan area of Rome, considering an urban and a periurban forest. Both forests are dominated byQuercus ilex L., which has been chosen as target species for its wide natural distribution in the Mediter-ranean Basin, as well as for its widespread use in urban contexts. The two studied sites were characterizedby different environmental stressor and forest management practices, resulting in different trends of leafgas exchanges, photosystems functionality and plant water status. During spring, gas exchanges werelower in the urban than in the periurban forest, due to higher air temperature and vapor pressure deficitin the latter site. During summer, instead, in the periurban area the functionality of Q. ilex was affectedby drought, which did not occur in the urban forest due to higher summer rainfalls as well as periodicirrigations. The water use efficiency was basically lower in the urban park, as well as the photosystemsfunctionality. Differences in the intensity of the main phenological phases were also highlighted. Ourresults point out that the two GIs fulfill a complementary role in the ESs provision in the metropolitanarea of Rome, in relation to the ozone removal and the resulting air quality improvement and climateregulation
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Assessment of ozone threat on a coastal maquis ecosystem in relation with water availability and inorganic nitrogen gaseous compounds
No full textAssessment of ozone threat on a coastal maquis ecosystem in relation with water availability and inorganic nitrogen gaseous compound
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