| 1. |
- Frenkel, Martin, et al.
(författare)
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Improper excess light energy dissipation in Arabidopsis results in a metabolic reprogramming
- 2009
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Ingår i: BMC Plant Biology. - : Springer Science and Business Media LLC. - 1471-2229. ; 9:12, s. 1-16
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Tidskriftsartikel (refereegranskat)abstract
- Background: Plant performance is affected by the level of expression of PsbS, a key photoprotective protein involved in the process of feedback de-excitation (FDE), or the qE component of non-photochemical quenching, NPQ. Results: In studies presented here, under constant laboratory conditions the metabolite profiles of leaves of wild-type Arabidopsis thaliana and plants lacking or overexpressing PsbS were very similar, but under natural conditions their differences in levels of PsbS expression were associated with major changes in metabolite profiles. Some carbohydrates and amino acids differed ten-fold in abundance between PsbS-lacking mutants and over-expressers, with wild-type plants having intermediate amounts, showing that a metabolic shift had occurred. The transcriptomes of the genotypes also varied under field conditions, and the genes induced in plants lacking PsbS were similar to those reportedly induced in plants exposed to ozone stress or treated with methyl jasmonate (MeJA). Genes involved in the biosynthesis of JA were up-regulated, and enzymes involved in this pathway accumulated. JA levels in the undamaged leaves of field-grown plants did not differ between wild-type and PsbS-lacking mutants, but they were higher in the mutants when they were exposed to herbivory. Conclusion: These findings suggest that lack of FDE results in increased photooxidative stress in the chloroplasts of Arabidopsis plants grown in the field, which elicits a response at the transcriptome level, causing a redirection of metabolism from growth towards defence that resembles a MeJA/JA response.
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| 2. |
- Aune, Karin, et al.
(författare)
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Isolation and edge effects among woodland key habitats in Sweden : making fragmentation into forest policy?
- 2005
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Ingår i: Biological Conservation. - : Elsevier BV. - 0006-3207 .- 1873-2917. ; 124:1, s. 89-95
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Tidskriftsartikel (refereegranskat)abstract
- Fragmentation of natural forests is a major threat to forest biodiversity. In areas with a long history of forestry, the remaining patches of old forests constitute only a minor part of the landscape. In such situations small stands may be valuable and important for conservation. However, as they may suffer from strong edge effects and isolation, their value may be lower than anticipated. In Sweden a national inventory of woodland key habitats (WKHs) has identified about 1% of the forest landscape as sites where red-listed species occur or may occur. Most are small (national median 1.4 ha) and isolated stands within an intensively managed landscape. The present analyses calculate WKH core area based on a range of depths of edge influence, and isolation based on both distance to nearest WKH and a weighted isolation measure that includes all neighboring WKHs and protected forest. These analyses are done on the WKHs in Norrbotten County in northern Sweden and include almost 5000 stands. The actual core area in the WKHs is about 30% given a 50 m edge influence. The degree of isolation is species dependent but the results indicate that only species with high dispersal abilities may effectively utilize the network of WKHs. For species with effective dispersal distances of less than 2 km the network is probably insufficient. The results emphasize the need to create buffer zones, to increase reserve areas and to manage the matrix so that species dispersal is promoted. This likely includes a necessity to aggregate biodiversity efforts on the landscape scale.
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| 3. |
- Axelsson Linkowski, Weronika, et al.
(författare)
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Shifting Strategies between Generations in Sami Reindeer Husbandry : the Challenges of Maintaining Traditions while Adapting to a Changing Context
- 2020
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Ingår i: Human Ecology. - : Springer Science and Business Media LLC. - 0300-7839 .- 1572-9915. ; 48, s. 481-490
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Tidskriftsartikel (refereegranskat)abstract
- Many traditional pastoralist systems are greatly impacted by cumulative encroachments of other land users and by climate change. Understanding land degradation and the adaptive capacity of people who are dependent on the rangelands is an urgent priority for many areas in the world. In this research we explore how changing environmental conditions affect herding strategies on winter pastures and the role of indigenous and local traditional knowledge (ILK) in Sami reindeer husbandry. Our results indicate that traditional Sami reindeer herding strategies are still practiced, but that rapidly changing environmental circumstances are forcing herders into uncharted territories where these traditional strategies and the transmission of knowledge between generations may be of limited use. For example, rotational grazing is no longer possible as all pastures are being used, and changes in climate result in unpredictable weather patterns unknown to earlier generations.
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| 4. |
- Axelsson Linkowski, Weronika, et al.
(författare)
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Wolf and Bear Depredation on Livestock in Northern Sweden 1827-2014 : Combining History, Ecology and Interviews
- 2017
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Ingår i: Land. - : MDPI AG. - 2073-445X. ; 6:3
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Tidskriftsartikel (refereegranskat)abstract
- During the twenty-first century, large carnivores have increased in human dominated landscapes after being extinct or nearly extinct. This has resulted in increasing numbers of livestock killed by large carnivores. The intent of this paper is to give a land use-historical perspective on the recent livestock-carnivore conflict in boreal Sweden. More specifically we address: (1) depredation risks (livestock killed by carnivores) and (2) local knowledge of how to protect livestock from predation and whether it survived among pastoralists until the present. This study provides numeric information on carnivores, livestock and depredation, combined with oral information from summer farmers about livestock protection. We compare recent (since 1998) and historical (late nineteenth century) depredation rates in two Swedish counties. In Dalarna recent depredation rates are higher than historical rates while the opposite pattern is seen in Jamtland. Recent depredation rates in Dalarna are twice the recent rates in Jamtland, in contrast to the historical situation. Recent and historical depredation rates are of the same order. Summer farmers traditionally graze their livestock in forested areas where carnivores reside. Interviews show that traditional knowledge of how to protect livestock from carnivores was lost during the twentieth century, but recently new knowledge has developed leading to changes in summer farming practices. The carnivore-livestock situation today differs from the historical situation, not so much in levels of depredation, but mainly regarding the possibilities of farmers to face challenges associated with increasing carnivore populations.
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| 5. |
- Berg, Anna, et al.
(författare)
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A century of logging and forestry in a reindeer herding area in northern Sweden
- 2008
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Ingår i: Forest Ecology and Management. - : Elsevier. - 0378-1127 .- 1872-7042. ; 256, s. 1009-1020
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Tidskriftsartikel (refereegranskat)abstract
- Boreal forest ecosystems are generally highly sensitive to logging and other forestry activities. Thus, commercial forestry has had major effects on the forests and landscape structure in northern Sweden since the middle of the 19th Century, when it rapidly extended across the region. Lichens (which constitute up to 80% of reindeer forage in winter and early spring) have often been amongst the most severely affected ecosystem components. The overall aim of the present study was to analyze how forestry has influenced the potential supply of ground-growing lichens as winter forage for the reindeer in this region over the past ca. 100 years. For this purpose, we analysed changes in forest and stand structure in Scots pine-dominated (Pinus sylvestris L.) reindeer wintering areas in the southern part of the county Norrbotten (covering ca. 58,000 ha) using detailed historical forest inventories and management plans. We found that the amount of the forest types considered potentially good pasture (mainly middleaged and old pine forests) decreased during the first part of the 20th Century. However, the quality of grazing grounds was improved by forestry during this time mainly because selective logging made the forests more open which benefits lichen growth. During the last part of the 20th century forestry impaired the quality of grazing grounds in several ways, e.g. by clear-cutting and intensified use of various silviculturalmeasures. We conclude that ca. 30–50% of the winter grazing grounds have been lost in the study area because of intensive forest management during the last century. The spatially precise historical information about the affects of forestry on lichen pasture provided in this study can be used to direct forest management which will facilitate and promote reindeer herding in the future.
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| 6. |
- Bernes, Claes, et al.
(författare)
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What are the impacts of reindeer/caribou (Rangifer tarandus L.) on arctic and alpine vegetation? : A systematic review protocol
- 2013
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Ingår i: Environmental Evidence. - : BioMed Central (BMC). - 2047-2382. ; 2
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Tidskriftsartikel (refereegranskat)abstract
- Background: Reindeer and caribou (both belonging to the species Rangifer tarandus L.) are among the most important large herbivores in Eurasia’s and North America’s arctic, alpine and boreal zones. In Sweden, the impact of reindeer grazing on arctic and alpine vegetation has recently been re-evaluated. In the 1990s, records of grazing-related vegetation degradation helped to form a widespread perception that some mountain areas were overgrazed. However, later analyses have shown no evidence of large-scale overutilisation of reindeer ranges in the Swedish mountains.The present-day consensus is that overgrazing has been temporary and local, and that it rarely has caused permanent damage, but it is imperative to examine the scientific support for these views. Moreover, the Swedish Parliament has adopted an environmental quality objective according to which it is essential to preserve ‘a mountain landscape characterised by grazing’. No details have been given on how this goal is to be interpreted, which is another reason why the significance of reindeer grazing for arctic/alpine vegetation needs to be assessed.This protocol presents the methodology that will be used in a systematic review of the impact of reindeer herbivory in arctic and alpine ecosystems. The focus will be on Fennoscandia, but data from other parts of the range of R. tarandus will be used when deemed appropriate.Methods: The review will be based on primary field studies that compare vegetation subject to different degrees of reindeer/caribou herbivory (including grazing and browsing as well as trampling). Such comparisons can be either temporal, spatial or both. The review will cover impacts of herbivory in arctic, subarctic, alpine and subalpine areas (including the forest-tundra ecotone) across the range of R. tarandus, but not in boreal forests. Relevant aspects of vegetation include cover (abundance), biomass, diversity (e.g. species richness), structure, composition (including functional groups) and productivity.
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| 7. |
- Bernes, Claes, et al.
(författare)
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What are the impacts of reindeer/caribou (Rangifer tarandus L.) on arctic and alpine vegetation? : A systematic review
- 2015
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Ingår i: Environmental Evidence. - : BMC. - 2047-2382. ; 4:4
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Forskningsöversikt (refereegranskat)abstract
- Background: The reindeer (or caribou, Rangifer tarandus L.) has a natural range extending over much of Eurasia's and North America's arctic, alpine and boreal zones, yet its impact on vegetation is still unclear. This lack of a common understanding hampers both the management of wild and semi-domesticated reindeer populations and the preservation of biodiversity. To achieve a common platform, we have undertaken a systematic review of published studies that compare vegetation at sites with different reindeer densities. Besides biodiversity, we focused on effects on major plant growth forms. Methods: Searches for literature were made using online publication databases, search engines, specialist websites and bibliographies of literature reviews. Search terms were developed in English, Finnish, Norwegian, Russian and Swedish. Identified articles were screened for relevance based on titles, abstracts and full text using inclusion criteria set out in an a priori protocol. Relevant articles were then subject to critical appraisal of susceptibility to bias. Data on outcomes such as abundance, biomass, cover and species richness of vegetation were extracted together with metadata on site properties and other potential effect modifiers. Results: Our searches identified more than 6,000 articles. After screening for relevance, 100 of them remained. Critical appraisal excluded 60 articles, leaving 40 articles with 41 independent studies. Almost two thirds of these studies had been conducted in Fennoscandia. Meta-analysis could be made of data from 31 of the studies. Overall, effects of reindeer on species richness of vascular plants depended on temperature, ranging from negative at low temperature to positive at high temperature. Effects on forbs, graminoids, woody species, and bryophytes were weak or non-significant, whereas the effect on lichens was negative. However, many individual studies showed clear positive or negative effects, but the available information was insufficient to explain this context dependence. Conclusions: We see two pressing matters emerging from our study. First, there is a lack of research with which to build a circumpolar understanding of grazing effects, which calls for more studies using a common protocol to quantify reindeer impacts. Secondly, the highly context-dependent outcomes suggest that research and management have to consider local conditions. For instance, predictions of what a management decision would mean for the effects of reindeer on vegetation will have to take the variation of vegetation types and dominant growth forms, productivity, and grazing history into account. Policy and management have to go hand-in-hand with research in individual cases if the dynamics between plants, animals, and humans are to be sufficiently understood.
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| 8. |
- Bruun, Hans Henrik, et al.
(författare)
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Distinct patterns in alpine vegetation around dens of the Arctic fox
- 2005
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Ingår i: Ecography. - : Wiley. - 0906-7590 .- 1600-0587. ; 28:1, s. 81-87
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Tidskriftsartikel (refereegranskat)abstract
- The arctic fox Alopex lugopus excavates its dens in gravely ridges and hillocks, and creates a local environment quite distinct from the surrounding tundra or heath landscape. In northern Sweden, the vegetation of 18 dens of the arctic fox was investigated, as well as reference areas off the dens but in geologically and topographically similar locations. The species composition showed considerable differences between den and reference areas, with grasses and forbs occurring more abundantly on the dens, and evergreen dwarf-shrubs occurring more in reference areas. The effect of the foxes' activities is thought to be either through mechanical soil disturbance, or through nutrient enrichment via scats, urine, and carcasses. This was expected to result in differences in plant traits with key functional roles in resource acquisition and regeneration, when comparing dens with reference areas. We hypothesised that the community mean of specific leaf area (SLA) would differ if nutrient enrichment was the more important effect, and that seed weight, inversely proportional to seed number per ramet and hence dispersal ability, would differ if soil disturbance was the more important effect. Specific leaf area showed a significant difference, indicating nutrient enrichment to be the most important effect of the arctic fox on the vegetation on its dens. Arctic foxes act as ecosystems engineers on a small scale, maintaining niches for relatively short-lived nutrient demanding species on their dens in spite of the dominance of long-lived ericaceous dwarf-shrubs in the landscape matrix. Thus, foxes contribute to the maintenance of species richness on the landscape level.
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| 9. |
- Bruun, Hans Henrik, et al.
(författare)
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Effects of altitude and topography on species richness of vascular plants, bryophytes and lichens in alpine communities
- 2006
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Ingår i: Journal of Vegetation Science. - 1100-9233 .- 1654-1103. ; 17:1, s. 37-46
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Tidskriftsartikel (refereegranskat)abstract
- Question: What is the relationship between species richness of vascular plants, bryophytes and macrolichens, and two important gradients in the alpine environment, altitude and local topography? Location: Northernmost Fennoscandia, 250-152 m a.s.l. corresponding to the range between timberline and mountain top. Methods: The vegetation was sampled in six mountain areas. For each 25 vertical metres, the local topographic gradient from wind-blown ridge to snowbed was sampled in quadrats of 0.8 m x 0.8 m. Patterns in species richness were explored using Poisson regression (Generalized Linear Models). Functional groups of species, i.e. evergreen and deciduous dwarf-shrubs, forbs, graminoids, mosses, hepatics and lichens were investigated separately. Results: Functional groups showed markedly different patterns with respect to both altitude and topography. Species richness of all vascular plants showed a unimodal relationship with altitude. The same was true for graminoids, forbs and lichens analysed separately, but forb richness peaked at Much higher altitudes than total richness. The richness of dwarf-shrubs decreased monotonically with altitude, whereas richness of mosses and liverworts showed an increasing trend. Significant interactions between altitude and local topography were present for several groups. The unimodal pattern for total plant species richness was interpreted in terms of local productivity, physical disturbance, trophic interactions, and in terms of species pool effects. Conclusions: Patterns in local species richness result from the action of two opposing forces: declining species pool and decreasing intensity of competition with altitude.
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| 10. |
- Bruun, Hans Henrik, et al.
(författare)
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Environmental correlates of meso-scale plant species richness in the province of Harjedalen, Sweden
- 2003
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Ingår i: Biodiversity and Conservation. - 0960-3115 .- 1572-9710. ; 12:10, s. 2025-2041
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Tidskriftsartikel (refereegranskat)abstract
- We investigated the species richness of vascular plants at the scale of 5 3 5 km in the Swedish province of Harjedalen, and the relationship between richness and environment. Environmental variables included geographical, altitudinal, topographical, bedrock, soil type, and land-cover descriptors. The species richness was subdivided into groups of species with similar life-form, i.e. trees, dwarf shrubs, hydro- and helophytes, vascular cryptogams, forbs, graminoids, and mountain plants. The data were split at random into two equal subsets. Explanatory models were built by multiple linear regression on the first subset, and the models were validated on the second subset. The total species richness of vascular plants could be explained by sandy and clayey soil, the heterogeneity in bedrock types and the area of acid volcanic bedrock. The model could explain about 46% of the variation in species richness. The richness of trees and hydrophytes tended to decrease with altitude, whereas this was not the case for mountain plants. The latter group occurred frequently at low elevation, but then predominantly along streams and rivers. Clayey soils, sandy soils, and basic volcanic bedrock were the variables most frequently included in the regression models.
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