Publikasjoner
NIBIOs ansatte publiserer flere hundre vitenskapelige artikler og forskningsrapporter hvert år. Her finner du referanser og lenker til publikasjoner og andre forsknings- og formidlingsaktiviteter. Samlingen oppdateres løpende med både nytt og historisk materiale. For mer informasjon om NIBIOs publikasjoner, besøk NIBIOs bibliotek.
2013
Sammendrag
Nondetection of trees is a serious problem for the use of terrestrial laser scanning (TLS) in forest inventory applications. The use of multiple coregistered scans can reduce nondetection but may not eliminate it, and it carries substantial field and post-processing costs. We examined and extended previously developed theoretical approaches to modeling nondetection. The results suggested that tree size as well as multiple stand structural characteristics may be factors, but the theoretical models do not lend themselves to empirical estimation. We then used distance sampling techniques to identify detection probabilities and develop adjusted estimates for trees per hectare and basal area in nine forest stands in southern Norway. The results compared favorably with field estimates based on fixed-area plots. The estimated detection probabilities indicate that correction for nondetection is needed unless the search for trees is limited to very small distances from the scanner. Distance sampling appears promising when TLS is used in the context of temporary-plot forest inventories.
Forfattere
Alexander Kopatz Snorre Hagen Martin Smith Leif E. Ollila Paul Eric Aspholm Hans Geir EikenSammendrag
Human–bear conflicts occur frequently in the Pasvik Valley, Norway. We used a variantof the hair-trapping method with higher densities of traps (2.5 x 2.5 km grid) todetect brown bears moving near human settlements and livestock. We distributed 20hair traps for one month close to a farm with frequent observations of grazing bears.The study area consisted of one area close to the farm, and one adjacent area withoutsettlements. We collected 85 hair samples and identified 13 different individuals bySTR analysis. In the farm area, we detected 4 different males once, and a female thatwas detected in both areas. In comparison, nine bears (2 males and 7 females) weredetected for more than one week in the area without settlements, suggesting lowerroaming activity. Conclusively, hair trapping has the potential to survey bears at specificlocations of importance to the wildlife management.
Sammendrag
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Forfattere
Liv Østrem Håkon Pedersen Arve Arstein Wiktoria Kaczmarek-DerdaSammendrag
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Forfattere
Vidar Selås Sverre Kobro Geir Andreas SonerudSammendrag
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Sammendrag
The fauna of surface-active spiders was studied in 12 cereal fields, with two types of subcrop, and in four young (17 months old) perennial leys (grass/clover). The fields were located in the southeastern (A), central (B) and western (C) parts of Norway. In total, 3945 spiders were caught from May to September 2004, using pitfall traps. Linyphidae was the most numerous family, with Erigone atra Blackwall 1833 representing 56% of all trapped individuals. The total numbers of spider species and individuals were significantly higher in leys than in barley at sites where both crops were present (sites A and B), with on average 11 species and 93 specimens in barley, and 20 species and 393 specimens in leys. Thus, young perennial leys appeared to provide a better habitat for spiders than did cereal fields, as has previously been documented for older perennial leys. The use of multi-species crops instead of a single crop species undersown in cereals, tended to result in higher spider species diversity, but it did not influence the total number of specimens. An ordination (DCA) showed a clustering of the spider fauna from the same site, but no clear separation between main crop types (ley vs. barley) was apparent. The main crops, subcrops, and the surrounding environs of the cropped field seem to affect the diversity and abundance of spiders.
Sammendrag
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Forfattere
Jean-Pierre Sarthou Jean-Philippe Choisis A. Amossé Michaela Arndorfer Debra Bailey Katalin Balázs G. Balent M. Deconchat Peter Dennis Sebastian Eiter Wendy Fjellstad Jürgen Friedel Philippe Jeanneret Rob Jongman Max Kainz Gerardo Moreno Annie Ouin Maurizio Guido Paoletti Philippe Pointereau Siyka Stoyanova Davide Viaggi Aude Vialatte Sebastian Wolfrum Felix HerzogSammendrag
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