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South-eastern Norway (south-eastern + norway)

Distribution by Scientific Domains

Life Sciences	50%

Selected Abstracts

Regularity of species richness relationships to patch size and shape

ECOGRAPHY, Issue 4 2007
Einar Heegaard
This study aims to assess the degree of regularity in the effect of patch size and patch shape on plant species richness across a macroscale region, and to evaluate the implications for nature conservation. Our study area covers south-eastern Norway and contains 16 agricultural landscapes with 2162 patches. To analyse regularity a local linear mixed model (LLMM) was applied. This procedure estimates the richness trends due to shared effects of size and shape, and simultaneously provides the landscape-specific random effect. The latter is a direct estimate of the degree of irregularity between the landscapes, conditioned on specific values of size and shape. The results show a positive interaction between the shape and size of patches, which is repeated for all landscapes. The shape of the patches produces more regular patterns in species richness than the size of patches. This we attribute to effects of dispersal and distance to neighbouring patches of different environmentally conditioned species pools. Large and complex patches have shorter average distance to neighbouring patches (of different types) than large simple-shaped (circular) patches have. We attribute the higher species richness of the former, given a similar area, to a higher number of species dispersed from the outside into the more complex plot. For small patches, however, the distance to the edge is short relative to normal dispersal distances, for patches of all shapes. This explains why the positive effect of shape complexity on species richness is stronger for large patches. This interpretation is supported by a strong spatial correlation conditioned on the most complex patches. Theories of dynamics in biodiversity in patchy landscapes must consider shape as a regulator at the same level as size, and both shape and size of patches should be simultaneously taken into account for management planning. [source]

Long-term precipitation and slide activity in south-eastern Norway, autumn 2000

HYDROLOGICAL PROCESSES, Issue 4 2008
Christian Jaedicke
Abstract In autumn 2000 high amounts of precipitation caused a large number of landslides in south-eastern Norway. The precipitation reached more than 400% of the normal monthly values in November. In addition to the precipitation, groundwater monitoring showed unusual high levels. High air temperatures in the mountains caused the precipitation to fall as rain instead of snow, causing additional runoff in the catchments. In this paper, 90 landslides are presented that were studied and evaluated by the Norwegian Geotechnical Institute (NGI) in the counties effected by the slide activity. The landslide database serves as start point for an analysis of the connection between slide activity and precipitation. The analysis shows a high variability of the observed precipitation just a few days before the slides. This variability decreases significantly around 50 days prior to the slides when the results stabilize at about 400% of normal precipitation in a 50-day period. Comparison of these results to long time observations gives an estimate of return periods for the precipitation events. The 53 days accumulated precipitation has the highest return period of 132 years. This suggests that the high landslide activity in autumn 2000 in south-eastern Norway was caused by a long-term infiltration of large amounts of precipitation rather than high rainfall intensities during a short period. Copyright © 2007 John Wiley & Sons, Ltd. [source]

Habitat differentiation within the large-carnivore community of Norway's multiple-use landscapes

JOURNAL OF APPLIED ECOLOGY, Issue 5 2008
Roel May
Summary 1The re-establishment of large carnivores in Norway has led to increased conflicts and the adoption of regional zoning for these predators. When planning the future distribution of large carnivores, it is important to consider details of their potential habitat tolerances and strength of inter-specific differentiation. We studied differentiation in habitat and kill sites within the large-carnivore community of south-eastern Norway. 2We compared habitat selection of the brown bear Ursus arctos L., Eurasian lynx Lynx lynx L., wolf Canis lupus L. and wolverine Gulo gulo L., based on radio-tracking data. Differences in kill site locations were explored using locations of documented predator-killed sheep Ovis aries L. We modelled each species' selection for, and differentiation in, habitat and kill sites on a landscape scale using resource selection functions and multinomial logistic regression. Based on projected probability of occurrence maps, we estimated continuous patches of habitat within the study area. 3Although bears, lynx, wolves and wolverines had overlapping distributions, we found a clear differentiation for all four species in both habitat and kill sites. The presence of bears, wolves and lynx was generally associated with rugged, forested areas at lower elevations, whereas wolverines selected rugged terrain at higher elevations. Some degree of sympatry was possible in over 40% of the study area, although only 1·5% could hold all four large carnivores together. 4Synthesis and applications. A geographically differentiated management policy has been adopted in Norway, aimed at conserving viable populations of large carnivores while minimizing the potential for conflicts. Sympatry of all four carnivores will be most successful if regional zones are established of adequate size spanning an elevational gradient. High prey densities, low carnivore densities, low dietary overlap and scavenging opportunities have most probably led to reduced competitive exclusion. Although regional sympatry enhances the conservation of an intact guild of large carnivores, it may well increase conflict levels and resistance to carnivore conservation locally. [source]