A Quantitative Assessment of Buffers among Temperature Variations, Livestock, and the Human Population of Iceland, 1784 to 1900     

Daniel E. Vasey 《Climatic change》2001,48(1):243-263

In this study two statistical techniques were used to assess buffers within the farm food chain in late preindustrial Iceland. Both methods arrived at similar quantitative assessments. The chain's tangible links were grass, livestock, and the human population, but it began with temperature, the primary determinant of grass yield and a proxy for grass yield in this study. The buffers were large in spite of the marginal nature of cattle, sheep, and horse farming in the subarctic climate, and the poverty of much of the population. One method of study involved comparison of livestock reductions and human population decrease in seven crises between 1784 and 1888, with attention to temperature data for crises after 1823, when continuous systematic meteorological observations began. The other method is time-series analysis using temperature observations, livestock counts which began in 1817, and several human demographic variables. The discussion focuses on likely buffers, notably alternative sources of winter fodder for livestock and of food for the human population.  相似文献   

Fissure swarms and fracture systems within the Western Volcanic Zone,Iceland – Effects of spreading rates     

《Journal of Structural Geology》2016

The Western Volcanic Zone (WVZ) in Iceland is ∼120 km long and 40 km wide. It offers an opportunity to study rift zones in a local ultra-slow spreading area close to a hotspot. Fractures were mapped from aerial photographs and digital elevation models. Most surface fractures are located in the southern part of the WVZ. The majority of the fractures have a north-northeasterly orientation, some deviations occur from this, especially in the north part of the WVZ. Fracture orientations are therefore quite uniform in the southern, faster spreading part of the WVZ, but more irregular in the slower-spreading northern part. This suggests different stress fields in the north part, which could be due to the influence of the Hreppar microplate and possibly also due to stress fields induced by crustal deformation because of changes in glacial load in the area. Such glacially-induced stress fields may have similar or even more influence than crustal spreading in the slower spreading northern part of the WVZ. Lower fracture density towards the north within the WVZ suggests lower frequency of rifting events in the north part, in accordance with less spreading in the north as measured by GPS geodetic measurements.  相似文献   

Feeding habits of demersal fish in Icelandic waters: a multivariate approach     

Jaworski  Andrzej; Ragnarsson  Stefan Aki 《ICES Journal of Marine Science》2006,63(9):1682-1694

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Collapse of the fishery for Iceland scallop (Chlamys islandica) in Breidafjordur, West Iceland     

Jonasson  Jonas P.; Thorarinsdottir  Gudrun; Eiriksson  Hrafnkell; Solmundsson  Jon; Marteinsdottir  Gudrun 《ICES Journal of Marine Science》2007,64(2):298-308

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Drift probabilities for Icelandic cod larvae   总被引：1，自引：0，他引：1  

Brickman  David; Marteinsdottir  Gudrun; Logemann  Kai; Harms  Ingo H. 《ICES Journal of Marine Science》2007,64(1):49-59

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The invasion of the intertidal canopy-forming alga Fucus serratus L. to southwestern Iceland: Possible community effects     

Agnar Ingólfsson 《Estuarine, Coastal and Shelf Science》2008

The intertidal serrated wrack, Fucus serratus L. (Fucales: Phaeophyceae), has become an abundant canopy-forming alga along a ca. 100 km stretch of shore in southwestern Iceland in the last century. Its distribution has not changed noticeably since a survey in 1975/1976. Many experimental studies have shown that canopy-forming algae can have profound effects on the community structure. Although such experiments involving F. serratus are few it was decided to test predictions from these experiments on a geographical scale by comparing community compositions within the area where F. serratus is a dominant algae (since at least 1975/1976) with an adjacent area of similar size where F. serratus is absent (with a single exception without consequences). The work is based on measurements on some 372 stations in the F. serratus area, termed region A, and 227 stations from the F. serratus-free area, termed region B. Percentage cover of algae and sessile invertebrates was estimated on 2 m² on each station and animals collected from 800 cm² from each station. The vertical distribution of F. serratus was most similar to that of Fucus distichus and the two species often grew intermingled on the lower part of the shore. F. serratus appeared to have reduced the cover of F. distichus in the lowermost part of the shore, while having little or no effect on other canopy-forming species. The low abundance of Semibalanus balanoides in the F. serratus area (region A) is in line with experiments showing detrimental effect on this barnacle by whiplash of F. serratus. In general algal grazers were more abundant in region A, consistent with the greater attractiveness of F. serratus than other canopy-forming species to grazers, although this may be partly explained by the abundance of understorey algae in region A.  相似文献   

A new early Holocene cryptotephra from northwest Scotland     

Patricia H. Ranner  Judy R. M. Allen  Brian Huntley 《第四纪科学杂志》2005,20(3):201-208

Clarification of the temporal relationships amongst records of environmental change is dependent on accurate timescales. Event markers such as tephra layers are extremely important for constraining chronologies and providing tie points. In this report we present evidence of a previously unknown early Holocene Icelandic cryptotephra from a lake in northern Scotland—the ‘An Druim Tephra’. The calibrated radiocarbon age of 9560 cal. yr BP for this new cryptotephra makes it an important addition to the suite of cryptotephras now recorded from the last glacial termination and early Holocene in northwest Europe. In addition we report evidence in support of a ‘Younger Borrobol Tephra’ from Lateglacial sediments of Allerød age. Copyright © 2005 John Wiley & Sons, Ltd.  相似文献   

Landscape in the sagas of Icelanders: The concepts of land and landsleg     

《Norsk geografisk tidsskrift. Norwegian journal of geography》2012,66(4):177-192

This article presents a study of the Icelandic landscape concept, and its meaning and embedded connotations. The present-day understanding of the concept provides the point of departure to some of the oldest preserved examples of the term. The analysis thus centres upon the sagas of Icelanders that were written in the Middle Ages. The paper reveals that in the 14th century the concept referred to morphological qualities of land, and was often associated with an aesthetic appreciation thereof. The meaning of landscape as natural scenery has been explained as the outcome of artistic articulations of social relations in the wake of the Renaissance and Romanticism. Such accounts, however, do not explain the aesthetic connotations associated with the Icelandic landscape concept in the Middle Ages, described in this article. The results of the study thus indicate that there may be more to the landscape concept within the cultural domain defined by the Germanic languages than hitherto revealed, particularly in terms of aesthetic experiences of the natural environment. Subsequently, this article emphasises the importance of identifying the culturally embedded meaning of landscape as a concept in the Icelandic context, for successful implementation of the concept in planning practices.  相似文献   

Simulating Icelandic vegetation cover during the Holocene Implications for long-term land degradation   总被引：2，自引：0，他引：2  

Rannveig Ólafsdóttir  Peter Schlyter  & Hörður V. Haraldsson 《Geografiska Annaler: Series A, Physical Geography》2001,83(4):203-215

We have simulated the spatial relationship between temperature change and long-term potential vegetation cover dynamics. The results show that the potential vegetation and birch forest range is highly sensitive to the temperature conditions. Around 3000 BP the simulated potential vegetation cover began to decrease and at the time of the Viking settlement, in AD 874 (1076 BP ), vegetation and forest cover was already in decline. The climate driven decline continued to an unprecedented low potential for vegetation for the Holocene that lasted c. 600 years, i.e. between AD c . 1300 and 1900. These interpretations are further supported by geomorphological and pollen data.  相似文献   

Geomorphological observations and related natural hazards using merged remotely sensed data: a case study in the Corinthos area (NE Peloponnese, S. Greece)     

Ioannis Gatsis  reas Pavlopoulos  & Isaak Parcharidis 《Geografiska Annaler: Series A, Physical Geography》2001,83(4):217-228

Natural hazards are mostly related to the activation of combined geomorphological and geological processes that control landform development. The study area is located in the NE part of Peloponnese (Corinthos prefecture). It is a typical agricultural area with intense relief, the result of active tectonics and important human intervention. This study demonstrates the benefits from the synergism of SAR data (ERS-2) and optical data (SPOT2-XS) in order to highlight the possible natural-hazardprone areas. These data give different and complementary information since the radar signal depends mostly on topography, surface roughness and soil moisture, whereas the visible/infrared channels provide spectral information mostly on vegetation and land use/cover. The application presented here was focused on the enhancement of the high erosion risk areas, the improvement of the terrain interpretation, the mapping and highlighting of the landform morphology, and a more accurate determination of the main factors that control the flooding risk of Corinthos town.  相似文献