scholarly journals Spatial, environmental and anthropogenic effects on the taxon composition of hybridizing Daphnia

2008 ◽  
Vol 363 (1505) ◽  
pp. 2943-2952 ◽  
Author(s):  
Barbara Keller ◽  
Justyna Wolinska ◽  
Marina Manca ◽  
Piet Spaak
Keyword(s):  
Species Complex ◽  
Competitive Ability ◽  
Habitat Characteristics ◽  
Daphnia Galeata ◽  
The North ◽  
Low Phosphorus ◽  
The Alps ◽  
Time Specific ◽  
The Impact ◽  
Taxon Composition

The competitive ability of hybrids, compared with their parental taxa, can cover a wide fitness range from poor to superior. For example communities of the Daphnia galeata – hyalina – cucullata species complex often show hybrid dominance. We tested whether taxa composition of 43 European lakes inhabited by this species complex can be explained by habitat characteristics (e.g. size descriptors, trophy level) or geography. We found that D. galeata occurs more frequently south of the Alps, whereas D. hyalina and D. cucullata are found more in the north. Lakes with D. galeata dominance had higher temperatures whereas D. hyalina dominance could be attributed to low phosphorus loads. The dominance of F 1 -hybrids, however, was not explainable with current environmental variables. In a subset of 28 lakes, we studied the impact of eutrophication history on F 1 -hybrid success. Lakes with the highest trophic state in the past tended to be dominated by F 1 -hybrids. Our data demonstrate that human-mediated habitat disturbance (eutrophication) has facilitated hybrid success and altered the Daphnia taxon composition across lakes. At the same time, specific habitat conditions might provide a refuge from hybridization for native genotypes.

scholarly journals Modes and mechanisms of a Daphnia invasion

2012 ◽  
Vol 279 (1740) ◽  
pp. 2936-2944 ◽  
Author(s):  
Piet Spaak ◽  
Jennifer Fox ◽  
Nelson G. Hairston
Keyword(s):  
Local Response ◽  
Daphnia Galeata ◽  
Daphnia Longispina ◽  
Eutrophic Lakes ◽  
The North ◽  
Geographically Distributed ◽  
The Alps ◽  
Two Temperatures ◽  
Countergradient Selection ◽  
New Habitats

Whether exotic species invade new habitats successfully depends on (i) a change in the invaded habitat that makes it suitable for the invader and (ii) a genetic change in the invading taxon that enhances its fitness in the new habitat, or both. We dissect the causes of invasions of Swiss lakes, north of the Alps, by Daphnia galeata (a zooplankter typical of eutrophic lakes, e.g. those south of the Alps, which are also warmer) by comparing the fitness performance of eight geographically distributed clones that were fed algal-food typical of oligotrophic versus eutrophic conditions at two temperatures. Daphnia longispina , native to oligotrophic Swiss lakes, served as a reference. Daphnia galeata requires eutrophic food to persist, whereas D. longispina survives and grows on oligotrophic food but does even better on eutrophic food. Invasion by D. galeata is further explained because invading clones from the north perform better on eutrophic food and at cooler temperatures than native clones from the south, suggesting a local response to countergradient selection. Our data support the hypothesis that populations of the invader in northern lakes are dominated by well-adapted genotypes. Our results illustrate how environmental change (i.e. eutrophication) and local adaptation can act together to drive a successful invasion.

Nachhaltigkeit im Wald – vor und hinter der Welle der Globalisierung | Sustainable Forest Management – In Front and Behind the Wave of Globalization

2000 ◽  
Vol 151 (12) ◽  
pp. 502-507
Author(s):  
Christian Küchli
Keyword(s):  
Forest Management ◽  
Cultural Landscape ◽  
Sustainable Forest Management ◽  
Essential Element ◽  
Specific Situation ◽  
The South ◽  
The North ◽  
Time Space ◽  
Starting Point ◽  
The Impact

Are there any common patterns in the transition processes from traditional and more or less sustainable forest management to exploitative use, which can regularly be observed both in central Europe and in the countries of the South (e.g. India or Indonesia)? Attempts were made with a time-space-model to typify those force fields, in which traditional sustainable forest management is undermined and is then transformed into a modern type of sustainable forest management. Although it is unlikely that the history of the North will become the future of the South, the glimpse into the northern past offers a useful starting point for the understanding of the current situation in the South, which in turn could stimulate the debate on development. For instance, the patterns which stand behind the conflicts on forest use in the Himalayas are very similar to the conflicts in the Alps. In the same way, the impact of socio-economic changes on the environment – key word ‹globalisation› – is often much the same. To recognize comparable patterns can be very valuable because it can act as a stimulant for the search of political, legal and technical solutions adapted to a specific situation. For the global community the realization of the way political-economic alliances work at the head of the ‹globalisationwave›can only signify to carry on trying to find a common language and understanding at the negotiation tables. On the lee side of the destructive breaker it is necessary to conserve and care for what survived. As it was the case in Switzerland these forest islands could once become the germination points for the genesis of a cultural landscape, where close-to-nature managed forests will constitute an essential element.

Healthcare System in the Arctic Zone of Russia. Known and Emerging Issues and Solutions to Them

2019 ◽  
pp. 3-20
Author(s):  
V.N. Leksin
Keyword(s):  
Metallurgical Industry ◽  
Healthcare Services ◽  
The Arctic ◽  
Russian Arctic ◽  
Arctic Zone ◽  
Shift Workers ◽  
The North ◽  
Medical Institutions ◽  
Emerging Issues ◽  
The Impact

The impact on healthcare organization on the territory of Russian Arctic of unique natural and climatic, demographic, ethnic, settlement and professional factors of influencing the health of population, constantly or temporarily living on this territory is studied. The necessity is substantiated of various forms and resource provision with healthcare services such real and potential patients of Arctic medical institutions, as representatives of indigenous small peoples of the North, workers of mining and metallurgical industry, military personnel, sailors and shift workers. In this connection a correction of a number of All-Russian normative acts is proposed.

A general practice provider federation in a mixed health economy in England: a case study investigation

2018 ◽  
Vol 68 (suppl 1) ◽  
pp. bjgp18X696929
Author(s):  
Jill Mitchell
Keyword(s):  
General Practice ◽  
Shared Vision ◽  
Health Economy ◽  
Structured Interviews ◽  
The North ◽  
Common Strategy ◽  
Common Purpose ◽  
Collaborative Working ◽  
The Impact

BackgroundThere is an emerging debate that general practice in its current format is out-dated and there is a requirement to move to a federated model of provision where groups of Practices come together. The emergence of federations has developed over the past 5 years but the factors that influence how federations develop and the impact of this new model is an under researched area.AimThe study explored the rationale around why a group of independent GP practices opted to pursue an alternative business venture and the benefits that this strategy offered.MethodA single organisational case study of a federation in the North of England was conducted between 2011–2016. Mixed methods data collection included individual and group semi-structured interviews and quantitative surveys.ResultsFederations promote collaborative working, relying on strategic coherence of multiple individual GP practices through a shared vision and common purpose. Findings revealed many complexities in implementing a common strategy across multiple independent businesses. The ability of the federation to gain legitimacy was two dimensional – externally and internally. The venture had mixed successes, but their approach to quality improvement proved innovative and demonstrated outcomes on a population basis. The study identified significant pressures that practices were experiencing and the need to seek alternative ways of working but there was no shared vision or inclination to relinquish individual practice autonomy.ConclusionOrganisational development support is critical to reform General Practice. Whether central funding through the GP Five Year Forward View will achieve the scale of change required is yet to be evidenced.

The Impact of Sanctions on North Korea’s Foreign Trade from the Perspective of the Comparative Advantage Theory

2019 ◽  
pp. 4-15
Author(s):  
I. A. Korgun ◽  
G. D. Toloraya
Keyword(s):  
Foreign Trade ◽  
Competitive Advantage ◽  
National Economy ◽  
North Korea ◽  
Rent Seeking ◽  
Economic Transformation ◽  
Global Trade ◽  
Negative Consequences ◽  
The North ◽  
The Impact

The presented study analyzes the opportunities for North Korea to capitalize on its competitive advantages in foreign trade in the context of sanctions.Aim. The study aims to identify mechanisms that allow North Korea to engage in foreign trade in circumvention of UN sanctions and to analyze their impact on the national economy.Tasks. The authors analyze the structure of North Korea’s national economy, its initial competitive advantage, identify the specific features of North Korea’s foreign trade in the context of sanctions, and determine the consequences of illicit trade in circumvention of sanctions for the national economy.Methods. This study uses an interdisciplinary approach that combines the classical theory of competitive advantage with the concept of rent seeking, with the concept of rent seeking and analysis of trade flows.Results. The study shows that, despite the restrictions imposed by sanctions, North Korea strives to make the most of its advantages, such as resource availability and cheap labor, in global trade. The country builds its own export-import chains in circumvention of sanctions. These chains are rather mobile, flexible, and controlled by the elite. As a result, benefits from trade that could be evenly distributed among the population are concentrated in the hands of a narrow segment of society. ‘Rent seeking’ makes it possible to formulate the negative consequences of these processes for the North Korean economy and the international community.Conclusions. Solving the North Korean issue requires an economic transformation in the country through the replacement of restrictive sanctions with more constructive ones. The exclusion of North Korea from open global trade leads to the country’s marginalization and impairs the transparency of international commodity flows.

Environmental impact of nutrients from nordic fish farming

1995 ◽  
Vol 31 (10) ◽  
pp. 61-71 ◽  
Author(s):  
M. Enell
Keyword(s):  
Major Part ◽  
Fish Farming ◽  
Fish Farms ◽  
Feed Composition ◽  
The North ◽  
Comprehensive Development ◽  
The Baltic ◽  
Inland Water Bodies ◽  
The Impact ◽  
Feed Coefficient

During the last 20 years there has been an interesting development of the Nordic fish farming, with regard to the feeding and farming technology and to the increase in production quantities. During the period 1974-1994 the production increased from 15,800 to about 250,000 tonnes/year. In 1974 the major part of the production was in Denmark, and in 1994 the major part was in Norway. The nutrient impact of fish farming on surrounding sea areas is mainly a function of the feed coefficient, the feed composition and metabolic processes in the fish. The comprehensive development of the feed composition and the feeding technology has resulted in reduced load of unmetabolized nutrients from fish farms, calculated per tonne fish produced. In 1974 the mean Nordic feed coefficient was 2.08 and in 1994 the coefficient was 1.25. Feed coefficients of 1.0-1.1 are now reported for Danish and Norwegian freshwater and marine fish farms. The nitrogen (N) and phosphorus (P) content of the feed has decreased, in addition the quality of the nutrient substances in the feed has changed, especially for N. The N content has decreased from 7.8 to 6.8% during the period 1974-1994 and the content of P has decreased from 1.7 to 0.7% during the same period. This development of the feed coefficient and the feed composition has resulted in a present load from a typical Nordic fish farm of 55 kg N and 4.8 kg P/t fish produced. The figures for 1974 were 132 kg N and 31 kg P/t fish produced. The Nordic fish farming production in 1994 resulted in a load of about 13,750 t N and about 1,200 t P on the actual recipients. The load from the Swedish, Finnish and Danish fish farming operations, with the Baltic Sea and the Skagerrak as the recipients, is negligible in comparison with other pollution sources. The quantities of N and P from the fish farming are equal to 0.5% of the atmospheric deposition on the sea surface and 3% of the atmospheric P load. Norwegian, Icelandic and the Faroe Islands fish farming operations are using the North Sea and the Norwegian Sea as the recipients. However, the nutrient load from single fish farms in certain coastal and inland water bodies can be significant and must be considered in the impact assessment together with other sources.

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