| 1. |
- Berglund, Håkan, et al.
(författare)
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Nested plant and fungal communities : the importance of area and habitat quality in maximizing species capture in boreal old-growth forests
- 2003
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Ingår i: Biological conservation. - 0006-3207. ; 112:3, s. 319-328
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Tidskriftsartikel (refereegranskat)abstract
- Knowledge of the distribution of rare species is crucial for species conservation in fragmented habitats. Species communities often exhibit nestedness, i.e. species in species-poor sites comprise a subset of richer ones. Thus, rare species are confined to species-rich sites. We evaluate whether plant and fungal communities in 46 old-growth spruce forest patches (0.17–12 ha) exhibit nestedness. The question whether a single large patch or several small patches capture most species (i.e. the SLOSS-issue) is evaluated in combination with species saturation analyses. All species groups exhibited significant nestedness. Area was generally related to nestedness, i.e. rare species were over-represented in the largest patches. Species saturation analysis indicated that large patches accumulated more Red-list species in patch interiors than small patches. Thus, rare and Red-list species were best captured in large patches. However, nestedness also emerged in equal sized sample plots, i.e. rare species were over-represented in high quality habitats. Thus, small habitats of high quality should not be neglected in a conservation perspective.
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| 2. |
- Bergman, Karl-Olof, 1965-, et al.
(författare)
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Distribution of occupied and vacant sites and migration of Lopinga achine (Nymphalidae : Satyrinae) in a fragmented landscape
- 2001
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Ingår i: Biological Conservation. - 0006-3207 .- 1873-2917. ; 102:2, s. 183-190
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Tidskriftsartikel (refereegranskat)abstract
- The distribution of occupied and vacant sites and migration of the threatened butterfly Lopinga achine were studied in the province of ╓sterg÷tland, Sweden. The probability of occupation increased with increasing patch area and decreasing distance to the nearest occupied patch, presumably due to different probabilities of colonisation and survival of the populations inhabiting the patches. Probability of female emigration from and immigration to a patch increased with decreasing area. Middle-sized patches produced the largest number of female migrants, although the highest fraction was noted for the smallest patches, and the greatest number of females was marked in the largest patch. The fraction of resident females, but not males, increased with increasing area. The observed occupancy and migration pattern have important conservation implications: all but two populations comprising three or more individuals were within 740 m of the nearest neighbour, indicating the need for networks of suitable, closely situated patches. ⌐ 2001 Elsevier Science Ltd. All rights reserved.
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| 3. |
- Bergman, Karl-Olof, 1965-, et al.
(författare)
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Population structure and movements of a threatened butterfly (Lopinga achine) in a fragmented landscape in Sweden
- 2002
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Ingår i: Biological Conservation. - 0006-3207 .- 1873-2917. ; 108:3, s. 361-369
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Tidskriftsartikel (refereegranskat)abstract
- The red-listed butterfly Lopinga achine was studied by mark-recapture methods in southern Sweden for three seasons. We examined movement within and between populations and egg production in relation to age. The majority of the movements were small with mean movements between recaptures of 45-54 m for males and 94-116 m for females. There were few movements between sites, 20 of 996 recaptured males moved and 36 of 391 recaptured females, even though the distance to other sites was in many cases < 100 m. The distance moved and the number of females moving between sites increased with increasing age. On average, a female that moves does so after laying two-thirds of its eggs in its natal site. It is therefore important to take account of the proportion of reproductive effort involved in dispersal when estimating colonisation ability. The males did not move more with increasing age. Female behaviour can be seen as a "spread-the-risk" strategy, an adaptation to the successional habitat of L. achine, whose natal site sooner or later will deteriorate. Butterflies like L. achine living in successional habitats may exhibit mobility that is intermediate between butterflies living in ephemeral habitats (very mobile) and in long-lived habitats (sedentary). ⌐ 2002 Elsevier Science Ltd. All rights reserved.
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| 4. |
- Dalén, Love, et al.
(författare)
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Is the endangered Fennoscandian arctic fox (Alopex lagopus) population genetically isolated?
- 2002
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Ingår i: Biological Conservation. - 0006-3207 .- 1873-2917. ; 105:2, s. 171-178
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Tidskriftsartikel (refereegranskat)abstract
- The arctic fox population in Fennoscandia is on the verge of going extinct after not being able to recover from a severe bottleneck at the end of the 19th century. The Siberian arctic fox population, on the other hand, is large and unthreatened. In order to resolve questions regarding gene flow between, and genetic variation within the populations, a 294 bp long part of the mitochondrial hypervariable region 1 was sequenced. This was done for 17 Swedish, 15 Siberian and two farmed foxes. Twelve variable nucleotide sites were observed, which resulted in 10 different haplotypes. Three haplotypes were found in Sweden and seven haplotypes were found in Siberia. An analysis of molecular variance showed a weak, but significant, differentiation between the populations. No difference in haplotype diversity was found between the populations. A phylogenetic analysis revealed that the three Swedish haplotypes were not monophyletic compared to the Siberian haplotypes. These results indicate a certain amount of gene flow between the two populations. both before and after the bottleneck. Restocking the Fennoscandian population with arctic foxes from Siberia might therefore be a viable option.
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| 5. |
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| 6. |
- Hersteinsson, P., et al.
(författare)
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The Arctic Fox in Fennoscandia and Iceland - Management Problems
- 1989
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Ingår i: Biological Conservation. - : Elsevier BV. - 0006-3207 .- 1873-2917. ; 49:1, s. 67-81
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Tidskriftsartikel (refereegranskat)abstract
- The arctic for Alopex lagopus was an important fur animal in Fennoscandia until the 1920s when numbers crashed, and in spite of total protection for over half a century has not recovered and is now regarded as vulnerable. In Iceland, on the other hand, the species is well established and can withstand heavy exploitation by man, being regarded as vermin and hunted at all seasons. In this paper we review the latest available information on the status of the arctic fox in the Nordic countries, both with regard to minimum sizes and fluctuations in population, and various factors which have been suggested as the cause of the non-recovery of the population in Fennoscandia. These include fewer available large mammal carcasses due to the near-disappearance of the wolf, increased competition with the red fox, increased predation by red foxes on arctic foxes, etc. The views that arctic foxes are an important predator on sheep in Iceland at present, and that foxhunting alone in its present form is capable of significantly reducing the population there, are challenged. At present there is insufficient information to make sound management programmes for the arctic fox populations in Fennoscandia and Iceland. Suggestions are made concerning those factors which need to be explored so that workable management programmes can be put into effect in the two regions.
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| 7. |
- Nordén, Björn, 1965, et al.
(författare)
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Relative importance of coarse and fine woody debris for the diversity of wood-inhabiting fungi in temperate broadleaf forests
- 2004
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Ingår i: Biological Conservation. - 0006-3207. ; 117:1, s. 1-10
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Tidskriftsartikel (refereegranskat)abstract
- Dead wood is considered important in forest conservation, but patterns of fungal diversity on dead wood have rarely been quantified. We investigated the relative importance of coarse (diameter > 10 cm) and fine woody debris (1-10 cm) for fungi in broadleaf forests in southern Sweden. The numbers of species per unit wood volume and per forest area were significantly higher for fine than for coarse woody debris for both ascomycetes and basidiomycetes. When the number of species was plotted against the number of records, coarse woody debris was more species rich than fine woody debris for a given number of basidiomycete records. Of the ascomycetes. 75% were found exclusively on fine woody debris (the corresponding proportion for basidiomycetes is 30%), 2% Were found exclusively on coarse woody debris (basidiomycetes 26%, and 23%,) of the species were found on both diameter classes (basidiomycetes 44%). We conclude that fine woody debris is important for diversity of wood-inhabiting fungi, especially ascomycctes. in this forest type. However, coarse woody debris must also be provided to insure the occurrence of many species of basidiomycetes. (C) 2003 Elsevier Ltd. All rights reserved.
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| 8. |
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| 9. |
- Ranius, Thomas, et al.
(författare)
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The influence of forest regrowth, original canopy cover and tree size on saproxylic beetles associated with old oaks
- 2000
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Ingår i: Biological Conservation. - : Elsevier. - 0006-3207 .- 1873-2917. ; 95:1, s. 85-94
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Tidskriftsartikel (refereegranskat)abstract
- Abandoned management has caused many sites with free-standing, large oaks (Quercus robur) to become more shaded. This study shows how forest regrowth affects beetle species associated with old oaks in south-eastern Sweden. Beetles were trapped by pitfall traps placed in hollows and window traps placed near hollows in oak trunks in pasture woodlands. We assessed the influence of forest regrowth, tree size and original canopy cover on the species richness of saproxylic beetles (a total of 120 species identified) and the occurrence of 68 saproxylic beetle species in particular. Species richness was greatest in stands with large, free-standing trees. Large girth as well as low canopy cover increased frequency of occurrence for several species. Forest regrowth was found to be detrimental for many beetle species. As most localities with endangered beetles living in old oaks are small and isolated, ongoing management and the restoration of abandoned pasture woodlands should have a high priority in nature conservation.
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| 10. |
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