706 research outputs found

    Landscape Ecology of Birds on Mount Leconte, Great Smoky Mountains National Park

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    Landbirds form a significant component of wildlife resources in the Great Smoky Mountains National Park. The present study explored how forest structure and composition of deciduous-coniferous ecotones influenced diversity, richness, and relative abundance of bird species and how bird species responded to the spruce-fir community. Using a form of the variable-circular plot method, I conducted audio-visual censuses of diurnal birds on Mount LeConte. I established 212 geo-referenced census points on six trails, which were used as gradient-oriented transects (gradsects). I measured habitat characteristics at the same census points. I used forest community types for each point on gradsects to delineate boundaries. I applied The Tasseled-Cap (T-CAP) , a graphic description of the spectral-temporal development of locations, to analyze bird-habitat relationships in order to investigate the utility of Landsat T-CAP indices in predicting forest patterns and bird species\u27 richness and abundance. I derived elevation, slope, and aspect from differentially corrected GPS coordinates using ArcView Spatial Analyst and T-Cap indices from Landsat TM remotely sensed data for forest community types and each vegetation sampling station using Earth Resources Data Analysis System. My results showed correlations among the abundances of many bird species and elevational, floristic, and physiogonomic features of their habitat, both for univariate and multivariate characters. Both cover type and size class (dbh) were important to the breeding avifauna; various groups of breeding birds were associated with either one or both variables. Ecotones along the gradsects among forest types were perceived by many bird species as significant discontinuities. Zones of both rapid and gradual change in bird abundance were observed. For certain bird species, patterns of bird distribution and forest types coincided. Individual species responded to patchiness, vegetation structure, and elevation, sometimes in a predictable manner. I observed clusters of species and communities along my derived zones that appeared to be different. Species expanded or contracted their distributions in localities where the homogenous ecotone was displaced upward or downward in elevation relative to the location of the ecotone on Mount LeConte. Spatial fluctuations were, in general, related to zonal transitions in forest types. T-CAP indices were related to species\u27 responses to changes in landscape structure and composition. Distinct patterns in vegetation that corresponded with different forest types and zones of rapid and gradual change in bird abundance were observed. Greenness and wetness values differentiated closed canopy fir stands from all other classes

    DCF Data Call Coverage Report for the Mediterranean and Black Sea in 2014

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    DG Mare called the DCF Data from Member States in the Mediterranean and Black Sea on April 2014, defining the deadline of 9 June 2014 for data submissions from member states, under the Community Framework of Data Collection Regulation (DCR) (Council Regulation (EC) № 199/2008 of 25th February 2008). A second deadline specific for the Black Sea was established on 8 September 2014. The data call also defined a third deadline 12 January 2015 for the submission of trawl surveys data for Mediterranean MS. aruptii. The DCF data submitted by national correspondents are duly evaluated in the present coverage report by JRC DCF team as part of an Administrative Arrangement with DG MARE. The report provides a detailed review of the timeliness and completeness of data submissions by Member States.JRC.G.3-Maritime affair

    Multi-Criteria Decision Analysis as a tool to extract fishing footprints and estimate fishing pressure: application to small scale coastal fisheries and implications for management in the context of the Maritime Spatial Planning Directive

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    In the context of the Maritime Spatial Planning Directive and with the intention of contributing to the implementation of a future maritime spatial plan, it was decided to analyze data from the small scale coastal fisheries sector of Greece and estimate the actual extent of its activities, which is largely unknown to date. To this end we identified the most influential components affecting coastal fishing: fishing capacity, bathymetry, distance from coast, Sea Surface Chlorophyll (Chl-a) concentration, legislation, marine traffic activity, trawlers and purse seiners fishing effort and no-take zones. By means of Multi-Criteria Decision Analysis (MCDA) conducted through a stepwise procedure, the potential fishing footprint with the corresponding fishing intensity was derived. The method provides an innovative and cost-effective way to assess the impact of the, notoriously hard to assess, coastal fleet. It was further considered how the inclusion of all relevant anthropogenic activities (besides fishing) could provide the background needed to plan future marine activities in the framework of Marine Spatial Planning (MSP) and form the basis for a more realistic management approach

    “Once upon a Time in the Mediterranean”. Long Term Trends of Mediterranean Fisheries Resources Based on Fishers’ Traditional Ecological Knowledge

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    We investigate long-term changes in the Mediterranean marine resources driving the trawl fisheries by analysing fishers’ perceptions (Traditional Ecological Knowledge, TEK) throughout the Mediterranean Sea for the last 80 years. To this end, we conducted an extended set of interviews with old experienced fishers that enabled us to classify species (or taxa) as 'decreasing' or 'increasing' both in terms of abundance, as well as average size in the catch. The aspect that most clearly emerged in all the investigated areas over time was the notable increase of fishing capacity indicators, such as engine power and fishing depth range. Atlantic mackerel, poor cod, scorpionfishes, striped seabream, and John Dory demonstrated a decreasing trend in the fishers' perceived abundance, while Mediterranean parrotfish, common pandora, cuttlefish, blue and red shrimp, and mullets gave indications of an increasing temporal trend. Although, as a rule, trawler captains did not report any cataclysmic changes (e.g. extinctions), when they were invited to estimate total overall catches, a clear decreasing pattern emerged; this being a notable finding taking into account the steep escalation of fishing efficiency during the past century. The overall deteriorating status of stocks in most Mediterranean regions calls for responsible management and design of rebuilding plans. This should include historical information accounting for past exploitation patterns that could help defining a baseline of fish abundance prior to heavy industrial fisheries exploitation.JRC.G.3-Maritime affair

    a4a short research project: Stock assessment of Hellenic Small Pelagic Stocks

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    With the objective of applying the a4a methods to real life situations the JRC held a Workshop on stock assessment for the Hellenic small pelagic stocks in the Aegean Sea (JRC, Italy) between the 4th and 7th of May 2015. The main objectives were to compare assessment models and incorporate environmental indices into stock forecasts.JRC.G.3-Maritime affair

    Old Info for a New Fisheries Policy: Discard Ratios and Lengths at Discarding in EU Mediterranean Bottom Trawl Fisheries

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    Discarding is considered globally among the most important issues for fisheries management. The recent reform of the Common Fisheries Policy establishes a landing obligation for the species which are subject to catch limits and, in the Mediterranean, for species which are subject to Minimum Conservation Reference Size (MCRS) as defined in Annex III to Regulation (EC) No 1967/2006. Additionally, several other initiatives aim to reduce unwanted catches of target and bycatch species, including species of conservation concern. This raises the need to study discarding patterns of (mainly) these species. In this work we collated a considerable amount of historical published information on discard ratios and lengths at discarding for species caught in EU Mediterranean bottom trawl fisheries. The main aim was to summarize the available historical records and make them more accessible for scientific and managerial needs, as well as to try identifying patterns in discarding. We show discard ratios and lengths at which 50% of the individuals were discarded (L50) for 15 species (9 bony fishes, three crustacean decapods, and three elasmobranchs). Discard ratios were usually low for target species such as hake, red mullets and highly commercial shrimps and exemptions from the landing obligation under the de minimis rules could be sought in several cases. Discard ratios were usually higher for commercial bycatch species. Discarding is affected by a combination of factors and for a given species, especially for non-target ones, discards are likely to fluctuate within a fishery, across seasons, years, and regions. For most species considered, L50s were lower than the MCRS (when in place) and length at first maturity. L50s of target species, such as hake, were very small due to the existence of market demands for small sized individuals. However, for species of low demand, like horse mackerels, a higher retention size was observed, often exceeding MCRS. Lengths at discarding are affected by legal provisions, market demands but also by biological, population, and ecological traits. Understanding the factors that affect discarding constitutes the starting point for designing mitigation measures and management plans to reduce discards and improve the sustainability of the stocksVersión del edito

    The “discard problem” in Mediterranean fisheries, in the face of the European Union landing obligation: the case of bottom trawl fishery and implications for management

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    Since the first introduction of the landing obligation (a.k.a. Discard ban) in 2015, the EU Mediterranean fisheries are facing some unforeseen challenges. The demersal bottom trawl fisheries, being the most significant contributors to the so-called 'discard problem', are confronted with the greatest challenges. Data from the Italian and the Greek fleet, spanning over two decades (1995–2015), were analysed with the intention of revealing the diversity and heterogeneity of the discard problem, especially for regulated species. Species composition of discards, as well as discarding rates, were shown to be irregular, fluctuating among areas, depth strata, seasons and years. Although fish dominated the discarded gross catch in weight, benthic invertebrates (other than commercial cephalopods and crustaceans) were the taxa discarded almost exclusively. The established minimum conservation reference size was largely ignored by fishers. From a management point of view, the present investigation suggests that the recently established Discard Management Plans lack scientific evidence (given the high intrinsic variability of the parameters and confusion regarding the rules) and provide exemptions from the landing obligation that will in practice allow the average Mediterranean bottom trawl vessel to continue business as usual. Moreover, detecting if these rules are actually respected is an almost impossible task for the Mediterranean control and enforcement authorities. Incentivizing the adoption of fishing technologies and practices that reduce pre-harvest mortality and post-harvest discards, while avoiding damage to sensitive marine species and habitats, seems the only way to move forward, rather than dealing with the problem after it has occurred

    An expanded CRISPRi toolbox for tunable control of gene expression in Pseudomonas putida

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    Owing to its wide metabolic versatility and physiological robustness, together with amenability to genetic manipulations and high resistance to stressful conditions, Pseudomonas putida is increasingly becoming the organism of choice for a range of applications in both industrial and environmental applications. However, a range of applied synthetic biology and metabolic engineering approaches are still limited by the lack of specific genetic tools to effectively and efficiently regulate the expression of target genes. Here, we present a single‐plasmid CRISPR‐interference (CRISPRi) system expressing a nuclease‐deficient cas9 gene under the control of the inducible XylS/Pm expression system, along with the option of adopting constitutively expressed guide RNAs (either sgRNA or crRNA and tracrRNA). We showed that the system enables tunable, tightly controlled gene repression (up to 90%) of chromosomally expressed genes encoding fluorescent proteins, either individually or simultaneously. In addition, we demonstrate that this method allows for suppressing the expression of the essential genes pyrF and ftsZ, resulting in significantly low growth rates or morphological changes respectively. This versatile system expands the capabilities of the current CRISPRi toolbox for efficient, targeted and controllable manipulation of gene expression in P. putida.<br/
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