scholarly journals The invasive alien freshwater flatworm Girardia tigrina (Girard, 1850) (Platyhelminthes, Tricladida) in Western Europe: new insights into its morphology, karyology and reproductive biology

2019 ◽  
pp. 1-21
Author(s):  
Giacinta Angela Stocchino ◽  
Ronald Sluys ◽  
Abdel Halim Harrath ◽  
Lamjed Mansour ◽  
Renata Manconi
Keyword(s):  
Native Species ◽  
Western Europe ◽  
Ecological Impact ◽  
Chromosome Complement ◽  
Detailed Knowledge ◽  
Italian Population ◽  
European Continent ◽  
Introduced Populations ◽  
New Information ◽  
Reproductive Apparatus

Invasions of alien species form one of the major threats to global biodiversity. Among planarian flatworms many species are known to be invasive, in several cases strongly affecting local ecosystems. Therefore, a detailed knowledge on the biology of an invasive species is of utmost importance for understanding the process of invasion, the cause of its success, and the subsequent ecological impact on native species. This paper provides new information on the biology of introduced populations of the freshwater flatworm Girardia tigrina (Girard, 1850) from Europe. This species is a native of the Nearctic Region that was accidentally introduced into Europe in the 1920s. Since then, numerous records across the European continent bear witness of the invasiveness of this species, although only a few studies focused on the biology of the introduced populations. We report on the morphology of sexualized individuals from a fissiparous Italian population, representing the second record of spontaneous sexualization of fissiparous individuals in this species. A detailed morphological account of the reproductive apparatus of these ex-fissiparous animals is presented. Our results increased the number of morphological groups previously recognized for European populations of G. tigrina, thus corroborating the hypothesis on multiple independent introductions to this continent. Karyological results obtained from our fissiparous Italian individuals revealed a constant diploid chromosome complement of sixteen chromosomes. Further, we document the marked intraspecific variation in several morphological features of this species.

scholarly journals Superior predatory ability and abundance predicts potential ecological impact towards early-stage anurans by invasive ‘Killer Shrimp’ (Dikerogammarus villosus)

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Daniel A. Warren ◽  
Stephanie J. Bradbeer ◽  
Alison M. Dunn
Keyword(s):  
Body Size ◽  
Native Species ◽  
Western Europe ◽  
Rana Temporaria ◽  
Early Stage ◽  
Ecological Impact ◽  
Feeding Rates ◽  
Dikerogammarus Villosus ◽  
Invasive Amphipods ◽  
Near Future

AbstractInvasive alien species negatively impact upon biodiversity and generate significant economic costs worldwide. Globally, amphibians have suffered considerable losses, with a key driver being predation by large invasive invertebrate and vertebrate predators. However, there is no research regarding the potential ecological impact of small invertebrate invaders. The invasive freshwater amphipod Dikerogammarus villosus can act as a top predator capable of displacing native amphipods and preying heavily upon a range of native species. Listed as one of Europe’s top 100 worst invaders, D. villosus has significantly restructured freshwater communities across western Europe and is expected to invade North America in the near future. Here we explore the ecological impact of invasive D. villosus upon UK native and invasive amphibians (Rana temporaria and Xenopus laevis respectively) using the “Relative Impact Potential” (RIP) metric. By combining estimations of per capita effects (i.e. functional response; FR) and relative field abundances, we apply the RIP metric to quantify the potential ecological impact of invasive D. villosus upon embryonic and larval amphibian prey, compared to the native amphipod Gammarus pulex. Both native and invasive amphipods consumed early-stage amphibians and exhibited potentially destabilising Type II FRs. However, larger body size in invasive D. villosus translated into a superior FR through significantly lower handling times and subsequently higher maximum feeding rates—up to seven times greater than native G. pulex. Higher invader abundance also drove elevated RIP scores for invasive D. villosus, with potential impact scores predicted up to 15.4 times greater than native G. pulex. Overall, D. villosus is predicted to have a greater predatory impact upon amphibian populations than G. pulex, due primarily to its larger body size and superior field abundance, potentially reducing amphibian recruitment within invaded regions.

High predatory efficiency and abundance drive expected ecological impacts of a marine invasive fish

2020 ◽  
Vol 637 ◽  
pp. 195-208 ◽  
Author(s):  
EM DeRoy ◽  
R Scott ◽  
NE Hussey ◽  
HJ MacIsaac
Keyword(s):  
Invasive Species ◽  
Native Species ◽  
Ecological Impact ◽  
Marine Species ◽  
Ecological Impacts ◽  
Negative Effects ◽  
Marine Predator ◽  
Eastern Gulf Of Mexico ◽  
Red Grouper ◽  
Per Capita

The ecological impacts of invasive species are highly variable and mediated by many factors, including both habitat and population abundance. Lionfish Pterois volitans are an invasive marine species which have high reported detrimental effects on prey populations, but whose effects relative to native predators are currently unknown for the recently colonized eastern Gulf of Mexico. We used functional response (FR) methodology to assess the ecological impact of lionfish relative to 2 functionally similar native species (red grouper Epinephelus morio and graysby grouper Cephalopholis cruentata) foraging in a heterogeneous environment. We then combined the per capita impact of each species with their field abundance to obtain a Relative Impact Potential (RIP). RIP assesses the broader ecological impact of invasive relative to native predators, the magnitude of which predicts community-level negative effects of invasive species. Lionfish FR and overall consumption rate was intermediate to that of red grouper (higher) and graysby grouper (lower). However, lionfish had the highest capture efficiency of all species, which was invariant of habitat. Much higher field abundance of lionfish resulted in high RIPs relative to both grouper species, demonstrating that the ecological impact of lionfish in this region will be driven mainly by high abundance and high predator efficiency rather than per capita effect. Our comparative study is the first empirical assessment of lionfish per capita impact and RIP in this region and is one of few such studies to quantify the FR of a marine predator.

From Black Death to Black Hole

2018 ◽  
Author(s):  
Marcin Piatkowski
Keyword(s):  
Economic Development ◽  
Black Hole ◽  
Sixteenth Century ◽  
Eastern Europe ◽  
Rule Of Law ◽  
Western Europe ◽  
Black Death ◽  
European Continent ◽  
The Past

In this chapter I explain why Poland and most countries in Eastern Europe have always lagged behind Western Europe in economic development. I discuss why in the past the European continent split into two parts and how Western and Eastern Europe followed starkly different developmental paths. I then demonstrate how Polish oligarchic elites built extractive institutions and how they adopted ideologies, cultures, and values, which undermined development from the late sixteenth century to 1939. I also describe how the elites created a libertarian country without taxes, state capacity, and rule of law, and how this ‘golden freedom’ led to Poland’s collapse and disappearance from the map of Europe in 1795. I argue that Polish extractive society was so well established that it could not reform itself from the inside. It was like a black hole, where the force of gravity is so strong that the light could not come out.

scholarly journals Introduced delicacy or native species? A natural origin of Bermudian terrapins supported by fossil and genetic data

2008 ◽  
Vol 4 (2) ◽  
pp. 216-219 ◽  
Author(s):  
James F Parham ◽  
Mark E Outerbridge ◽  
Bryan L Stuart ◽  
David B Wingate ◽  
Helmut Erlenkeuser ◽  
...  
Keyword(s):  
Native Species ◽  
Genetic Data ◽  
Oceanic Islands ◽  
Invasive Pest ◽  
Diamondback Terrapin ◽  
Malaclemys Terrapin ◽  
Natural Distribution ◽  
Naturally Occurring ◽  
Introduced Populations ◽  
Marine Reptile

Humans have greatly altered the natural distribution of species, making it difficult to distinguish between natural and introduced populations. This is a problem for conservation efforts because native or introduced status can determine whether a species is afforded protection or persecuted as an invasive pest. Holocene colonization events are especially difficult to discern, particularly when the species in question is a naturally good disperser and widely transported by people. In this study, we test the origin of such a species, the diamondback terrapin ( Malaclemys terrapin ), on Bermuda using a combination of palaeontologic (fossil, radiometric and palaeoenvironmental) and genetic data. These lines of evidence support the hypothesis that terrapins are relatively recent (between 3000 and 400 years ago) natural colonizers of Bermuda. The tiny population of Bermudian terrapins represents the second naturally occurring non-marine reptile that still survives on one of the most densely populated and heavily developed oceanic islands in the world. We recommend that they should be given protection as a native species.

scholarly journals Simulating the integrated summertime Δ<sup>14</sup>CO<sub>2</sub> signature from anthropogenic emissions over Western Europe

2014 ◽  
Vol 14 (14) ◽  
pp. 7273-7290 ◽  
Author(s):  
D. Bozhinova ◽  
M. K. van der Molen ◽  
I. R. van der Velde ◽  
M. C. Krol ◽  
S. van der Laan ◽  
...  
Keyword(s):  
Western Europe ◽  
Fossil Fuel ◽  
Atmospheric Transport ◽  
Forecast Model ◽  
Horizontal Resolution ◽  
Nuclear Industry ◽  
Anthropogenic Emissions ◽  
European Continent ◽  
Plant Samples ◽  
Fossil Fuel Emissions

Abstract. Radiocarbon dioxide (14CO2, reported in Δ14CO2) can be used to determine the fossil fuel CO2 addition to the atmosphere, since fossil fuel CO2 no longer contains any 14C. After the release of CO2 at the source, atmospheric transport causes dilution of strong local signals into the background and detectable gradients of Δ14CO2 only remain in areas with high fossil fuel emissions. This fossil fuel signal can moreover be partially masked by the enriching effect that anthropogenic emissions of 14CO2 from the nuclear industry have on the atmospheric Δ14CO2 signature. In this paper, we investigate the regional gradients in 14CO2 over the European continent and quantify the effect of the emissions from nuclear industry. We simulate the emissions and transport of fossil fuel CO2 and nuclear 14CO2 for Western Europe using the Weather Research and Forecast model (WRF-Chem) for a period covering 6 summer months in 2008. We evaluate the expected CO2 gradients and the resulting Δ14CO2 in simulated integrated air samples over this period, as well as in simulated plant samples. We find that the average gradients of fossil fuel CO2 in the lower 1200 m of the atmosphere are close to 15 ppm at a 12 km × 12 km horizontal resolution. The nuclear influence on Δ14CO2 signatures varies considerably over the domain and for large areas in France and the UK it can range from 20 to more than 500% of the influence of fossil fuel emissions. Our simulations suggest that the resulting gradients in Δ14CO2 are well captured in plant samples, but due to their time-varying uptake of CO2, their signature can be different with over 3‰ from the atmospheric samples in some regions. We conclude that the framework presented will be well-suited for the interpretation of actual air and plant 14CO2 samples.

Writing and Literacy/Illiteracy

2015 ◽  
pp. 286-316
Author(s):  
Krešimir Matijević
Keyword(s):  
Roman Empire ◽  
Late Antiquity ◽  
Western Europe ◽  
Italian Population ◽  
Ancient Rome ◽  
Archaeological Evidence ◽  
Level Of Education ◽  
Roman Provinces ◽  
Pictorial Representations

This chapter examines archaeological evidence that demonstrates literacy/illiteracy in the Roman Empire based on the ancient written documents available, including stone inscriptions. It first considers the level of education amongst the Italian population in ancient Rome, particularly in the Roman provinces, along with the level of literacy prior to Roman provincialization in Western Europe. It then turns to other documents such as books, wooden tablets, small inscriptions, and pictorial representations, and the Roman military’s ability to read and write. Finally, it discusses the level of literacy in late antiquity.

Vikings

2012 ◽  
Author(s):  
Nancy L. Wicker
Keyword(s):  
Material Culture ◽  
North Atlantic ◽  
Western Europe ◽  
Viking Age ◽  
Historical Sources ◽  
European Continent ◽  
Early Medieval Period ◽  
The North ◽  
12Th Century ◽  
America South

The Viking Age spans the period from approximately 750 to 1100 ce in the Nordic countries of Denmark, Norway, and Sweden. The name “Viking” is used to refer to the inhabitants of Scandinavia and its colonies during the early medieval period, even though the name originally most likely referred only to sea-pirates from Scandinavia. Much of the research on the Vikings has focused on three great narratives of the Viking Age: expansion through raids, trade, and settlement; the beginnings of political unification of the three Scandinavian nations; and the Christianization of these kingdoms. The Viking incursions into the British Isles began late in the 8th century, and in the 9th century, Vikings pushed farther west to the North Atlantic and North America, south along the coast of the European continent, and east to Russia and the East and beyond, even into Central Asia. By the 12th century, Scandinavia is Christianized and the Viking Age is over. This list of works focuses on Material Culture and the Historical Sources—Western Europe of the Viking Age rather than the medieval literature (12th and 13th centuries) of Scandinavia and Iceland, except for brief mention of Eddic literature that may contain information from earlier times and has been influential for the study of the Vikings.

Information in the Welfare State: Problems and Approaches

1978 ◽  
Vol 21 (1_suppl) ◽  
pp. 165-180
Author(s):  
Yrjö Littunen
Keyword(s):  
Information Needs ◽  
Western Europe ◽  
Theoretical Orientation ◽  
School Science ◽  
State Regulation ◽  
Welfare States ◽  
The Other ◽  
Science Journalism ◽  
New Information ◽  
Partial Isolation

The most comprehensive approaches toward understanding information in modern ‘welfare states’ have been focussed on outlining state regulation in the monopoly stage of capitalism. This theoretical orientation has instigated a number of studies penetrating into the use of information for the purposes of state control and regulation, e.g. in income policies as well as in legislation. Less developed is the study of the other side of the dialectic: how do counter-processes manifest themselves in the course of increasing bureaucratic-corporativist regulation and control? Evidence on following tendencies in ‘welfare states’ in Western Europe and their accentuation in Scandinavia is discussed. (1) Fragmentation and partial isolation of the traditional information institutions (school, science, journalism) from contemporary information-steering processes, necessitated by increasing flows of raw information in the market of knowledge. (2) Emergence of new information-steering activities, often in organized, institutionalized forms. (3) New information-steering is developed for centralized, state-monopoly regulated information needs and, on the other hand, for democratic information needs: these trends and counter-trends depend not only on power changes in the class struggle but also on changes in the content and experience-coping of information available for the large majorities of the population.

Sliding Towards EC Membership: Norway in Scandinavian Perspective

1992 ◽  
Vol 27 (3) ◽  
pp. 330-344 ◽  
Author(s):  
Lars Svåsand ◽  
Ulf Lindström
Keyword(s):  
Eastern Europe ◽  
Western Europe ◽  
Abrupt Change ◽  
Internal Market ◽  
Political Agenda ◽  
The Political ◽  
Political Debate ◽  
European Continent ◽  
Single European Act ◽  
East West

THIS ARTICLE ADDRESSES THE PROBLEM OF NORWEGIAN membership in the EC. Why is it so difficult for Norway to follow in the tracks of Sweden and Finland, and for that matter the rest of Western Europe?The changes on the European continent since the collapse of the East-West divide have also altered the political agenda in the Scandinavian countries. The ambitions of the EC-internal market as well as the Single European Act speeded up a discussion of how Finland, Norway and Sweden should position themselves in order not to lose out economically and become marginalized politically. In Norway, the traumatic EC debate in 1972 had split the country, and the parties, into two camps, resulting in the rejection of EC membership by 53 per cent of the electorate. Since then, the issue has been absent from political debate. In Finland and Sweden the official rationale for not discussing the issue disappeared simultaneously with the regimes in Eastern Europe, suddenly pushing the topic onto the political agenda, causing an abrupt change in Swedish EC policy.

Land-use effects on water quality in an intensively managed catchment in the Australian humid tropics

2002 ◽  
Vol 53 (5) ◽  
pp. 931 ◽  
Author(s):  
R. G. V. Bramley ◽  
C. H. Roth
Keyword(s):  
Water Quality ◽  
Land Use ◽  
Ecological Impact ◽  
Humid Tropics ◽  
Detailed Knowledge ◽  
Total N ◽  
Sugarcane Production ◽  
Rural Land Use ◽  
Intensively Managed ◽  
Stream Waters

The minimization of environmental degradation that might arise as a result of agricultural production requires a detailed knowledge of the off-site effects of rural land use. This paper reports the results of an assessment of the effect of land use on water quality in the lower part of the catchment of the Herbert River, an intensively managed part of the humid tropics in north Queensland, where the major land uses are sugarcane production, cattle grazing and forestry. Compared with grazing and forestry, sugarcane production was found to have a significant impact on riverine water quality as evidenced by higher concentrations of nitrogen (N), phosphorus (P) and total suspended solids (TSS) in stream-waters draining land under sugarcane, a finding that was unaffected by the inclusion of sampling sites dominated by upper-catchment grazing. However, land use had no significant effect on the partitioning of N and P between mineral, organic and particulate phases in stream-waters, although the proportion in particulate form tended to be least for sugarcane-dominated sites. Irrespective of land use, the concentrations of both total N and P were dominated by soluble fractions, particularly in organic combination. These results suggest that, irrespective of the ecological impact of these nutrient and sediment loadings on freshwaters and the near-shore zone, there is considerable room for improvement in land management in the Australian humid tropics in terms of minimizing off-site export of both nutrients and sediment.

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