Land-cover and structural changes in a western Norwegian cultural landscape since 1865, based on an old cadastral map and a field survey   总被引：4，自引：2，他引：4  

Liv Norunn Hamre  Stein Tage Domaas  Ingvild Austad  Knut Rydgren 《Landscape Ecology》2007,22(10):1563-1574

Many studies of land-cover and structural changes in cultural landscapes have used historical maps as a source for information about past land-cover. All transformations of historical maps onto modern coordinate systems are however burdened with difficulties when it comes to accuracy. We show that a detailed land survey of the present landscape may enable transformation of an old cadastral map directly onto the present terrain with very high accuracy. The detailed resulting map enabled us to locate remnants of semi-natural grasslands and man-made structures with continuity from 1865 and to test hypotheses about relationships between landscape changes and landscape characteristics. The main land-cover change 1865–2002 was decrease of arable fields, and addition of three new land-cover classes: horticultural, orchard and abandoned areas. Of the 330 man-made structures present in 1865, only 58 remained in 2002, while 63 new structures had been built after 1865. We found that semi-natural grasslands with continuity since 1865 were situated on ground with significantly lower production capacity than mean 1865 production capacity. The man-made structures with continuity since 1865 were also associated with areas with significantly lower production capacity than the 1865 mean, situated in significantly steeper terrain but not further from the hamlet. Our study illustrates the potential of digitised and accurately transformed historical cadastral maps combined with detailed field surveys for analysis of land-cover and structural changes in the cultural landscape.  相似文献   

Selection experiments with salmon: IV. Growth of Atlantic salmon during two years in the sea     

Knut Gunnes  Trygve Gjedrem 《Aquaculture (Amsterdam, Netherlands)》1978,15(1):19-33

Brood stock of Atlantic salmon were sampled from 37 rivers or riversystems (strains) for three consecutive years. Each strain was represented by several full- and half-sib families. During the freshwater period each full-sib family was reared separately and each group was given as equal environmental conditions as possible. Fingerlings large enough to become 1-year-old smolt were freeze-branded and smolts from the different strains were sampled and transported to five salmon farms along the Norwegian coast. This paper deals with body weight and length of Atlantic salmon after a growth period of 2 years in the sea.Significant differences between strains were found for all three year classes. The interaction farm × strain was significant but accounted for only a small part of the total variation. It is concluded that genotype × environment interaction can be ignored when planning a selection programme for Altantic salmon for Norwegian farming conditions. A significant interaction sire × dam was found for the 1972 year-class, implying the presence of non-additive genetic variation. The heritabilities for body weight and length estimated from sire components (year-class 1973 and 1974) were quite high: 0.31 and 0.28, respectively. Genetic correlations between body weight and length were close to unity. The heritabilities for condition factor ($\text{K=}\text{weight in g}\text{(length in cm)}{}^3\text{·100}$ were small and none of the sire components were significant. It is concluded that the combination of weight and length used in calculating the K-factor has minor genetic basis.Genetic variation in body weight of Atlantic salmon is high, and about three times as high as for body length.  相似文献   

Molecular cloning and expression of insulin-like growth factor-I (IGF-I) in Eurasian perch (<Emphasis Type="Italic">Perca fluviatilis</Emphasis>): lack of responsiveness to growth hormone treatment     

Sissel?JentoftEmail author  Are?H.?Aastveit  ?ivind?Andersen 《Fish physiology and biochemistry》2004,30(1):67-76

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Some data on selection in tetraploid rye     

H. Wexelsen  K. Aastveit  M. Bragdø 《Euphytica》1961,10(2):244-256