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  • 1.
    Alatalo, Juha M
    et al.
    Uppsala Universitet, Campus Gotland.
    Jägerbrand, Annika K
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Molau, Ulf
    Göteborg Universitet.
    Climate change and climatic events: Community-, functional- and species-level responses of bryophytes and lichens to constant, stepwise, and pulse experimental warming in an alpine tundra2014In: Alpine Botany, ISSN 1664-2201, Vol. 124, no 2, p. 81-91Article in journal (Refereed)
    Abstract [en]

    We experimentally imposed three different kinds of warming scenarios over 3 years on an alpine meadow community to identify the differential effects of climate warming and extreme climatic events on the abundance and biomass of bryophytes and lichens. Treatments consisted of (a) a constant level of warming with open top chambers (an average temperature increase of 1.87 °C), (b) a yearly stepwise increase of warming (average temperature increases of 1.0; 1.87 and 3.54 °C, consecutively), and (c) a pulse warming, i.e., a single first year pulse event of warming (average temperature increase of 3.54 °C only during the first year). To our knowledge, this is the first climate change study that attempts to distinguish between the effects of constant, stepwise and pulse warming on bryophyte and lichen communities. We hypothesised that pulse warming would have a significant short-term effect compared to the other warming treatments, and that stepwise warming would have a significant mid-term effect compared to the other warming treatments. Acrocarpous bryophytes as a group increased in abundance and biomass to the short-term effect of pulse warming. We found no significant effects of mid-term (third-year) stepwise warming. However, one pleurocarpous bryophyte species, Tomentypnum nitens, generally increased in abundance during the warm year 1997 but decreased in control plots and in response to the stepwise warming treatment. Three years of experimental warming (all treatments as a group) did have a significant impact at the community level, yet changes in abundance did not translate into significant changes in the dominance hierarchies at the functional level (for acrocarpous bryophytes, pleurocarpous bryophytes, Sphagnum or lichens), or in significant changes in other bryophyte or lichen species. The results suggest that bryophytes and lichens, both at the functional group and species level, to a large extent are resistant to the different climate change warming simulations that were applied.

  • 2.
    Alatalo, Juha, M.
    et al.
    Uppsala Universitet.
    Jägerbrand, Annika
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Molau, Ulf
    Göteborgs Universitet.
    Testing reliability of short-term responses to predict longer-term responses of bryophytes and lichens to environmental change2015In: Ecological Indicators, ISSN 1470-160X, E-ISSN 1872-7034, Vol. 58, p. 77-85Article in journal (Refereed)
    Abstract [en]

    Environmental changes are predicted to have severe and rapid impacts on polar and alpine regions. At high latitudes/altitudes, cryptogams such as bryophytes and lichens are of great importance in terms of biomass, carbon/nutrient cycling, cover and ecosystem functioning. This seven-year factorial experiment examined the effects of fertilizing and experimental warming on bryophyte and lichen abundance in an alpine meadow and a heath community in subarctic Sweden. The aim was to determine whether short-term responses (five years) are good predictors of longer-term responses (seven years). Fertilizing and warming had significant negative effects on total and relative abundance of bryophytes and lichens, with the largest and most rapid decline caused by fertilizing and combined fertilizing and warming. Bryophytes decreased most in the alpine meadow community, which was bryophyte-dominated, and lichens decreased most in the heath community, which was lichen-dominated. This was surprising, as the most diverse group in each community was expected to be most resistant to perturbation. Warming alone had a delayed negative impact. Of the 16 species included in statistical analyses, seven were significantly negatively affected. Overall, the impacts of simulated warming on bryophytes and lichens as a whole and on individual species differed in time and magnitude between treatments and plant communities (meadow and heath). This will likely cause changes in the dominance structures over time. These results underscore the importance of longer-term studies to improve the quality of data used in climate change models, as models based on short-term data are poor predictors of long-term responses of bryophytes and lichens.

  • 3.
    Alatalo, Juha M
    et al.
    Qatar University.
    Jägerbrand, Annika
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Čuchta, Peter
    Academy of Science of the Czech Republic.
    Collembola at three alpine subarctic sites resistant to twenty years of experimental warming2015In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 5, article id 18161Article in journal (Refereed)
    Abstract [en]

    This study examined the effects of micro-scale, site and 19 and 21 years of experimental warming on Collembola in three contrasting alpine subarctic plant communities (poor heath, rich meadow, wet meadow). Unexpectedly, experimental long-term warming had no significant effect on species richness, effective number of species, total abundance or abundance of any Collembola species. There were micro-scale effects on species richness, total abundance, and abundance of 10 of 35 species identified. Site had significant effect on effective number of species, and abundance of six species, with abundance patterns differing between sites. Site and long-term warming gave non-significant trends in species richness.

    The highest species richness was observed in poor heath, but mean species richness tended to be highest in rich meadow and lowest in wet meadow. Warming showed a tendency for a negative impact on species richness. This long-term warming experiment across three contrasting sites revealed that Collembola is capable of high resistance to climate change. We demonstrated that micro-scale and site effects are the main controlling factors for Collembola abundance in high alpine subarctic environments. Thus local heterogeneity is likely important for soil fauna composition and may play a crucial role in buffering Collembola against future climate change.

  • 4.
    Alatalo, Juha, M.
    et al.
    Uppsala Universitet.
    Little, Chelsea, J.
    Uppsala Universitet.
    Jägerbrand, Annika
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Molau, Ulf
    Göteborgs Universitet.
    Vascular plant abundance and diversity in an alpine heath under observed and simulated global change2015In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 5, p. 1-11, article id 10197Article in journal (Refereed)
    Abstract [en]

    Global change is predicted to cause shifts in species distributions and biodiversity in arctic tundra. We applied factorial warming and nutrient manipulation to a nutrient and species poor alpine/arctic heath community for seven years. Vascular plant abundance in control plots increased by 31%. There were also notable changes in cover in the nutrient and combined nutrient and warming treatments, with deciduous and evergreen shrubs declining, grasses overgrowing these plots. Sedge abundance initially increased significantly with nutrient amendment and then declined, going below initial values in the combined nutrient and warming treatment. Nutrient addition resulted in a change in dominance hierarchy from deciduous shrubs to grasses. We found significant declines in vascular plant diversity and evenness in the warming treatment and a decline in diversity in the combined warming and nutrient addition treatment, while nutrient addition caused a decline in species richness. The results give some experimental support that species poor plant communities with low diversity may be more vulnerable to loss of species diversity than communities with higher initial diversity. The projected increase in nutrient deposition and warming may therefore have negative impacts on ecosystem processes, functioning and services due to loss of species diversity in an already impoverished environment.

  • 5.
    Ali, Arshad
    et al.
    East China Normal University.
    Molau, Ulf
    Göteborgs Universitet.
    Bai, Yang
    Chinese Academy of Sciences.
    Jägerbrand, Annika K
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Alatalo, Juha M.
    Qatar University.
    Diversity-productivity dependent resistance of an alpine plant community to different climate change scenarios2016In: Ecological research, ISSN 0912-3814, E-ISSN 1440-1703, Vol. 31, no 6, p. 935-945Article in journal (Refereed)
    Abstract [en]

    Here we report from a experiment imposing different warming scenarios [control with ambient temperature, constant level of moderate warming for 3 years, stepwise increase in warming for 3 years, and one season of high level warming (pulse) simulating an extreme summer event] on an alpine ecosystem to study the impact on species diversity–biomass relationship, and community resistance in terms of biomass production.

    Multiple linear mixed models indicate that experimental years had stronger influence on biomass than warming scenarios and species diversity. Species diversity and biomass had almost humpback relationships under different warming scenarios over different experimental years. There was generally a negative diversity–biomass relationship, implying that a positive diversity–biomass relationship was not the case.

    The application of different warming scenarios did not change this tendency. The change in community resistance to all warming scenarios was generally negatively correlated with increasing species diversity, the strength of the correlation varying both between treatments and between years within treatments. The strong effect of experimental years was consistent with the notion that niche complementarity effects increase over time, and hence, higher biomass productivity over experimental years. The strongest negative relationship was found in the first year of the pulse treatment, indicating that the community had weak resistance to an extreme event of one season of abnormally warm climate.

    Biomass production started recovering during the two subsequent years. Contrasting biomass-related resistance emerged in the different treatments, indicating that micro sites within the same plant community may differ in their resistance to different warming scenarios.

  • 6.
    During, Heinjo J
    et al.
    Utrecht University.
    Verduyn, Betty
    Utrecht University.
    Jägerbrand, Annika K
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment. Hokkaido University.
    Biomechanical properties of the terrestrial mosses Pleurozium schreberi (Brid.) Mitt. and Pogonatum japonicum Sull. & Lesq. along altitudinal gradients in northern Japan2015In: Arctoa: A Journal of Briology, ISSN 0131-1379, Vol. 24, p. 375-381Article in journal (Refereed)
    Abstract [en]

    Altitudinal gradients along mountain slopes provide valuable opportunities to study variation in plant traits in response to changes in environmental conditions along such  gradients. This study focused on biomechanical traits of two moss species, the more or less horizontally growing Pleurozium schreberi and the erect-growing Pogonatum japonicum, along altitudinal gradients on two mountains in Hokkaido, northern Japan.

    We measured stem diameter in two directions to determine the second moment of area I, used three-point bending tests with free stem ends to determine the slope of the force-deflection curve dF/dx, and used these data to calculate Young’s modulus and flexural rigidity of the stems. Both species showed much variation in all traits among replicates in the samples at each altitude. Environmental variation associated with altitude had more effect on the biomechanical traits of P. japonicum than on those of P. schreberi. Stems of P. japonicum were thicker (larger I) than those of P. schreberi and had a larger Young’s modulus and flexural rigidity. Stems tended to become thinner (lower second moment of area) and less rigid (lower flexural rigidity) at increasing altitude in both species.

  • 7.
    Gren, Ing-Marie
    et al.
    Sveriges Lantbruksuniversitet.
    Häggmark-Svensson, Tobias
    Sveriges Lantbruksuniversitet.
    Andersson, Hans
    Sveriges Lantbruksuniversitet.
    Jansson, Gunnar
    Sveriges Lantbruksuniversitet.
    Jägerbrand, Annika
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Using traffic data to estimate wildlife populations2015In: Journal of Bioeconomics, ISSN 1387-6996, E-ISSN 1573-6989, Vol. 18, no 1, p. 17-31Article in journal (Refereed)
    Abstract [en]

    Wildlife populations are threatened worldwide by, among others, habitat fragmentation and hunting pressure. An important impediment for the large scale, national and regional, management of the populations is the difficulty to quantify population dynamics. The purpose of this study is to present a tool for such estimations which is based on available data in several countries; traffic load and traffic accidents with wildlife. An econometric model is developed, which accounts for landscape characteristics. It is applied to wild boar in Sweden, for which data on traffic load and accidents for different counties and years are available. Landscape characteristics are introduced with direct or indirect effects on population growth. The indirect landscape model gives the best statistical performance, and the results show relatively small differences in calculated intrinsic growth rate among counties but considerable differences in predicted population developments.

  • 8. Jonsdottir, I.S.
    et al.
    Crittenden, P
    Jägerbrand, Annika
    Göteborg University.
    Measuring growth rates in bryophytes and lichens1997In: Summary document of 8th Annual ITEX Workshop. Royal Holloway Institute for Environmental Research, 19-22 April, 1997, 1997, , p. 10-15Conference paper (Other academic)
  • 9.
    Jägerbrand, A.K.
    et al.
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Alatalo, Juha M.
    Campus Gotland, Uppsala Universitet.
    Native roadside vegetation that enances soil erosion control in boreal Scandinavia2014In: Environments, ISSN 2076-3298, Vol. 1, p. 31-41Article in journal (Refereed)
    Abstract [en]

    This study focused on identifying vegetation characteristics associated with erosion control at nine roadside sites in mid-West Sweden. A number of vegetation characteristics such as cover, diversity, plant functional type, biomass and plant community structure were included. Significant difference in cover between eroded and non-eroded sub-sites was found in evergreen shrubs, total cover, and total above ground biomass. Thus, our results support the use of shrubs in order to stabilize vegetation and minimize erosion along roadsides. However, shrubs are disfavored by several natural and human imposed factors. This could have several impacts on the long-term management of roadsides in boreal regions. By both choosing and applying active management that supports native evergreen shrubs in boreal regions, several positive effects could be achieved along roadsides, such as lower erosion rate and secured long-term vegetation cover. This could also lead to lower costs for roadside maintenance as lower erosion rates would require less frequent stabilizing treatments and mowing could be kept to a minimum in order not to disfavor shrubs.                                                                                                             

  • 10.
    Jägerbrand, Annika
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Dead or alive? Testing the use of C:N ratios and chlorophyll fluorescence in vertical shoot profiles to determine depth of vitality and point of senescence in populations of bryophytes2015In: Lindbergia, ISSN 0105-0761, E-ISSN 2001-5909, Vol. 38, p. 4-13Article in journal (Refereed)
    Abstract [en]

    Bryophytes with indeterminate growth rarely exhibit clearly identifiable modules or age segments, but can be vertically divided into different physiologically active zones, since physiological activity normally declines vertically along the shoot profile depth. The aim of this study was to investigate whether it is possible to use C:N ratios (C/N)and/or parameters from chlorophyll fluorescence measurements (e.g. Fv/Fm, Fm or qN)to determine if bryophyte tissue is alive, senescent or dead, and at what distance along the shoot segment profile the moss tissue cease to live. Variation in C:N ratios and chlorophyll fluorescence between sites was also examined. This study shows that it is possible to separate alive, senescing and dead parts of the moss shoots in Pleurozium schreberi, and that chlorophyll fluorescence is a good method to use, whereas C/N varies between sites and species (for Hylcomium splendens and Racomitrium lanuginosum)and does not seem to reflect physiological activity to the same degree.

  • 11.
    Jägerbrand, Annika
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    LED och ekologiska effekter2015In: Ceebel Nyhetsbrev, Vol. 1, p. 1-3Article in journal (Other (popular science, discussion, etc.))
    Abstract [sv]

    LED har olika typer av ekologisk påverkan och kan i vissa fall leda till större effekter än traditionellt använd belysning. Samtidigt har LED potential att kunna utvecklas till en ekologisk neutral belysning. Det finns en rad olika saker man kan tänka på vid inköp av LED-lampor för att minimera ekologisk påverkan, såsom låg effektnivå, använda dimringsteknik, undvika oönskad ljusspridning och att försöka undvika lampor som har höga nivåer av våglängder under 500 nm.

  • 12.
    Jägerbrand, Annika
    Göteborg University.
    Patterns of species richness and vegetative performance in heath ecosystems at Thingvellir, Southwest Iceland2004In: Icelandic Agricultural Sciences, ISSN 1670-567X, Vol. 16-17, p. 29-38Article in journal (Refereed)
    Abstract [en]

    The Racomitrium lanuginosum (Hedw.) Brid. moss heath is a unique environment and is of great importance for co-occurring established vascular plants. A thick moss carpet can prevent or restrict the growth of vascular plants as they are exposed to more unfavourable growth conditions, but the effect on species richness and abundance is less known. To investigate the negative effects of a well-developed moss carpet on established vascular plants, patterns of species richness, shoot density, and number of leaves (Carex bigelowii Schwein. and Thalictrum alpinum L.) were studied in two different vegetation types, Racomitrium lanuginosum moss heath, and dwarf shrub heath in Þingvellir National Park, Southwest Iceland.

    Species richness was higher in dwarf shrub heath and increased proportionally with the size of the shrub patches. Total species richness and plant functional dominance did not differ between vegetation types. There were no differences found in shoot density, percentage of flowering and juveniles, number of leaves in Carex bigelowii, or shoot density, flowering percentage or number of leaves in Thalictrum alpinum between the vegetation types. However, leaf length of Carex bigelowii was higher in the dwarf shrubs heath, indicating more favourable growth conditions, shade or shelter effects. It is possible that translocation is taking place between the shoots of the clonal vascular plants in this study so that the plants themselves are counteracting unfavourable effects in the different vegetation types. The effect of global climatic change on moss heaths in Iceland is briefly discussed.

  • 13.
    Jägerbrand, Annika
    et al.
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Alatalo, Juha M.
    Uppsala Universitet.
    Effects of human trampling on abundance and diversity of vascular plants, bryophytes and lichens in alpine heath vegetation, Northern Sweden2015In: SpringerPlus, E-ISSN 2193-1801, Vol. 4, no 95Article in journal (Refereed)
    Abstract [en]

    This study investigated the effects of human trampling on cover, diversity and species richness in an alpine heath ecosystem in northern Sweden. We tested the hypothesis that proximity to trails decreases plant cover, diversity and species richness of the canopy and the understory. We found a significant decrease in plant cover with proximity to the trail for the understory, but not for the canopy level, and significant decreases in the abundance of deciduous shrubs in the canopy layer and lichens in the understory. Proximity also had a significant negative impact on species richness of lichens. However, there were no significant changes in species richness, diversity or evenness of distribution in the canopy or understory with proximity to the trail. While not significant, liverworts, acrocarpous and pleurocarpous bryophytes tended to have contrasting abundance patterns with differing proximity to the trail, indicating that trampling may cause shifts in dominance hierarchies of different groups of bryophytes. Due to the decrease in understory cover, the abundance of litter, rock and soil increased with proximity to the trail. These results demonstrate that low-frequency human trampling in alpine heaths over long periods can have major negative impacts on lichen abundance and species richness. To our knowledge, this is the first study to demonstrate that trampling can decrease species richness of lichens. It emphasises the importance of including species-level data on non-vascular plants when conducting studies in alpine or tundra ecosystems, since they often make up the majority of species and play a significant role in ecosystem functioning and response in many of these extreme environments.

  • 14.
    Jägerbrand, Annika
    et al.
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment. Hokkaido University.
    Alatalo, Juha M.
    Uppsala Universitet.
    Kudo, Gaku
    Hokkaido University.
    Variation in responses to temperature treatments ex situ of the moss Pleurozium schreberi (Willd. ex Brid.) Mitt.originating from eight altitude sites in Hokkaido, Japan2014In: Journal of Bryology, ISSN 0373-6687, E-ISSN 1743-2820, Vol. 36, no 3, p. 209-216Article in journal (Refereed)
    Abstract [en]

    Thermal acclimatisations are important for the survival and growth of individuals and populations but seldom studied for different populations of bryophytes. The aims of this study were to (I) investigate if responses to temperature treatments were independent of the site sampled or if the intra- and interpopulation variation in responses were larger than the responses to the temperature treatments (control, press, and pulse), and to (II) examine if experimental responses varied, depending on the sampled sites.

    We collected samples of the circumpolar bryophyte species, Pleurozium schreberi (Willd. ex Brid.) Mitt., originating from eight altitude sites on Mt. Oakan in Hokkaido, Japan, and exposed them to three different temperature treatments ex situ for four weeks. Thermal acclimatisation was estimated by measuring responses in growth length increase, biomass increase, number of branches, and the maximum quantum yield of PS II (Fv/Fm). We found that responses to temperature treatments were dependent of the site sampled, and that differences were most pronounced in the length increase. Results also shows that the responses to experimental treatments may differ between sites. Our results therefore raise important concerns regarding the general validity of both ex situ and in situ experiments when performed on a single or a limited number of sites.

  • 15.
    Jägerbrand, Annika K
    et al.
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment. Göteborgs Universitet.
    Alatalo, Juha M
    Jönköpings Universitet.
    Chrimes, Dillon
    University of Tokyo.
    Molau, Ulf
    Göteborgs Universitet.
    Plant community responses to 5 years of simulated climate change in meadow and heath ecosystems at a subarctic-alpine site2009In: Oecologia, ISSN 0029-8549, E-ISSN 1432-1939, Vol. 161, no 3, p. 601-610Article in journal (Refereed)
    Abstract [en]

    Climate change was simulated by increasing temperature and nutrient availability in an alpine landscape. We conducted a field experiment of BACI-design (before/after control/impact) running for five seasons in two alpine communities (heath and meadow) with the factors temperature (increase of ca. 1.5-3.0°C) and nutrients (5 g N, 5 g P per m 2) in a fully factorial design in northern Swedish Lapland. The response variables were abundances of plant species and functional types. Plant community responses to the experimental perturbations were investigated, and the responses of plant functional types were examined in comparison to responses at the species level. Nutrient addition, exclusively and in combination with enhanced temperature increase, exerted the most pronounced responses at the species-specific and community levels. The main responses to nutrient addition were increases in graminoids and forbs, whereas deciduous shrubs, evergreen shrubs, bryophytes, and lichens decreased. The two plant communities of heath or meadow showed different vegetation responses to the environmental treatments despite the fact that both communities were located on the same subarctic-alpine site. Furthermore, we showed that the abundance of forbs increased in response to the combined treatment of temperature and nutrient addition in the meadow plant community. Within a single-plant functional type, most species responded similarly to the enhanced treatments although there were exceptions, particularly in the moss and lichen functional types. Plant community structure showed BACI responses in that vegetation dominance relationships in the existing plant functional types changed to varying degrees in all plots, including control plots. Betula nana and lichens increased in the temperature-increased enhancements and in control plots in the heath plant community during the treatment period. The increases in control plots were probably a response to the observed warming during the treatment period in the region. © Springer-Verlag 2009.

  • 16.
    Jägerbrand, Annika K
    et al.
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Björk, Robert
    Göteborgs Universitet.
    Callaghan, Terry
    Seppelt, Rod
    Effects of climate change on tundra bryophytes2011In: Bryophyte ecology and climate change / [ed] Nancy Slack, Zoltan Tuba and Lloyd Stark, Cambridge University Press, 2011, 1, p. 211-236Chapter in book (Other academic)
  • 17.
    Jägerbrand, Annika K
    et al.
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Kudo, Gaku
    Hokkaido University.
    Alatalo, Juha M
    Högskolan på Gotland.
    Molau, Ulf
    Göteborgs Universitet.
    Effects of neighboring vascular plants on the abundance of bryophytes in different vegetation types2012In: Polar Science, ISSN 1873-9652, E-ISSN 1876-4428, Vol. 6, no 2, p. 200-208Article in journal (Refereed)
    Abstract [en]

    Due to the climate change, vegetation of tundra ecosystems is predicted to shift toward shrub and tree dominance, and this change may influence bryophytes. To estimate how changes in growing environment and the dominance of vascular plants influence bryophyte abundance, we compared the relationship of occurrence of bryophytes among other plant types in a five-year experiment of warming (T), fertilization (F) and T. +. F in two vegetation types, heath and meadow, in a subarctic-alpine ecosystem. We compared individual leaf area among shrub species to confirm that deciduous shrubs might cause severe shading effect. Effects of neighboring functional types on the performance of Hylocomium splendens was also analyzed.Results show that F and T. +. F treatments significantly influenced bryophyte abundance negatively. Under natural conditions, bryophytes in the heath site were negatively related to the abundance of shrubs and lichens and the relationship between lichens and bryophytes strengthened after the experimental period. After five years of experimental treatments in the meadow, a positive abundance relationship emerged between bryophytes and deciduous shrubs, evergreen shrubs and forbs. This relationship was not found in the heath site. Our study therefore shows that the abundance relationships between bryophytes and plants in two vegetation types within the same area can be different. Deciduous shrubs had larger leaf area than evergreen shrubs but did not show any shading effect on H. splendens. © 2012 Elsevier B.V. and NIPR.

  • 18.
    Jägerbrand, Annika K
    et al.
    Göteborgs Universitet.
    Lindblad, Karin E M
    Göteborgs Universitet.
    Björk, Robert G
    Göteborgs Universitet.
    Alatalo, Juha M
    Vinnova.
    Molau, Ulf
    Göteborgs Universitet.
    Bryophyte and lichen diversity under simulated environmental change compared with observed variation in unmanipulated alpine tundra2006In: Biodiversity and Conservation, ISSN 0960-3115, E-ISSN 1572-9710, Vol. 15, no 14, p. 4453-4475Article in journal (Refereed)
    Abstract [en]

    Effects of simulated environmental change on bryophyte and lichen species richness and diversity in alpine tundra were investigated in a 5-year experiment at Latnjajaure, northern Sweden. The experiment had a factorial design including fertilisation and temperature enhancement in one meadow and one heath plant community. Responses in species richness, biodiversity, and species composition of bryophytes and lichens to experimental treatments were compared to the observed variation in six naturally occurring plant communities. The combination of fertilisation and enhanced temperature resulted in a species impoverishment, for bryophytes in the bryophyte-dominated community, and for lichens in the lichen-dominated communities, but the species composition stayed within the observed natural variation. During the course of the study, no species new to the investigated mid-alpine landscape were recorded, but that scenario is realistic within a decade when comparing with the processes seen in vascular plants.

  • 19.
    Jägerbrand, Annika K
    et al.
    Göteborgs Universitet.
    Molau, Ulf
    Göteborgs Universitet.
    Alatalo, Juha M
    Göteborgs Universitet.
    Responses of bryophytes to simulated environmental change at Latnjajaure, northern Sweden2003In: Journal of Bryology, ISSN 0373-6687, E-ISSN 1743-2820, Vol. 25, no 3, p. 163-168Article in journal (Refereed)
    Abstract [en]

    We simulated a predicted environmental change in a subarctic-alpine plant community to study short-term growth in Hylocomium splendens, and three-year effects in abundance changes of the five most common bryophytes at Latnjajaure, northern Sweden. The experiment had a factorial design with increased temperature and nutrients, alone and in combination. Moss growth was measured during the 1995 growing season, and we measured species abundance before and after three years of environmental perturbation. The combined treatments of fertilizer and temperature enhancement caused a decreased growth in length and dry weight in H. splendens. There was a significant decrease in abundance of Rhytidium rugosum in the combined temperature and fertilizer treatment. The other four common bryophyte species (Aulacomnium turgidum, Dicranum groenlandicum, Hylocomium splendens, and Ptilidium ciliare) showed weaker, but not significant trends in the same direction. As the bryophytes are an important component of arctic and subarctic vegetation, we expect that they will play a key role in the impact of anticipated Global Change on the ecosystems.

  • 20.
    Jägerbrand, Annika
    et al.
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment. Hokkaido University.
    Kudo, Gaku
    Hokkaido University.
    Short-term responses in maximum quantum yield of PSII (Fv/Fm) to ex situ temperature treatment of populations of bryophytes originating from different sites in Hokkaido, Northern Japan2016In: Plants, ISSN 2223-7747, Vol. 5, no 2, p. 455-465Article in journal (Refereed)
    Abstract [en]

    There is limited knowledge available on the thermal acclimation processes for bryophytes, especially when considering variation between populations or sites. This study investigated whether short-term ex situ thermal acclimation of different populations showed patterns of site dependency and whether the maximum quantum yield of PSII (Fv/Fm) could be used as an indicator of adaptation or temperature stress in two bryophyte species: Pleurozium schreberi (Willd. ex Brid.) Mitt. and Racomitrium lanuginosum (Hedw.) Brid.

    We sought to test the hypothesis that differences in the ability to acclimate to short-term temperature treatment would be revealed as differences in photosystem II maximum yield (Fv/Fm). Thermal treatments were applied to samples from 12 and 11 populations during 12 or 13 days in growth chambers and comprised: (1) 10/5 °C; (2) 20/10 °C; (3) 25/15 °C; (4) 30/20 °C (12 hours day/night temperature).

    In Pleurozium schreberi, there were no significant site-dependent differences before or after the experiment, while site dependencies were clearly shown in Racomitrium lanuginosum throughout the study. Fv/Fm in Pleurozium schreberi decreased at the highest and lowest temperature treatments, which can be interpreted as a stress response, but no similar trends were shown by Racomitrium lanuginosum.

  • 21.
    Korpelainen, Helena
    et al.
    University of Helsinki.
    Jägerbrand, Annika K
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    von Cräutlein, Maria
    University of Helsinki.
    Genetic structure of mosses Pleurozium schreberi (Willd. ex Brid.) Mitt. and Racomitrium lanuginosum (Hedw.) Brid. along altitude gradients in Hokkaido, Japan2012In: Journal of Bryology, ISSN 0373-6687, E-ISSN 1743-2820, Vol. 34, no 4, p. 309-312Article in journal (Refereed)
  • 22.
    Little, Chelsea J
    et al.
    Uppsala Universitet.
    Jägerbrand, Annika K
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Molau, Ulf
    Göteborgs Universitet.
    Alatalo, Juha M
    Uppsala Universitet.
    Community and species-specific responses to simulated global change in two subarctic-alpine plant communities2015In: Ecosphere, ISSN 2150-8925, E-ISSN 2150-8925, Vol. 6, no 11, article id 227Article in journal (Refereed)
    Abstract [en]

    Long-term observational studies have detected greening and shrub encroachment in the subarctic attributed to current climate change, while global change simulations have showed that community composition and productivity may shift drastically in arctic, subarctic, and alpine tundra plant communities in the future. However, responses to global change can be highly species- and contextdependent. We examined community-level and species-specific responses to a six-year factorial temperature and nutrient (nitrogen and phosphorus) amendment experiment in two alpine plant communities in northern Sweden: a species-poor dwarf shrub heath, and a more species-rich meadow. We hypothesized that abundance responses to global change would be variable within commonly defined vascular plant functional groups (e.g., forbs, evergreen shrubs, deciduous shrubs) and that new species would appear in experimental plots over time due to the ameliorated growing conditions. We found that within most functional groups, species were highly individualistic with respect to the global change simulation, particularly within the forbs, whereas within the shrubs, responses were neutral to negative and widely variable in magnitude. In the heath community the response of the graminoid functional group was driven almost entirely by the grass Calamagrostis lapponica, which increased in abundance by an order of magnitude in the combined temperature and nutrient treatment. Furthermore, community context was important for species' responses to the simulations. Abundance of the pan-arctic species Carex bigelowii and Vaccinium vitis-idaea responded primarily to the temperature treatment in the meadow community whereas the nutrient treatment had stronger effects in the heath community. Over six growing seasons, more new species appeared in the experimental plots than in control plots in the meadow community, whereas in the heath community only one new species appeared. Our results from two closely situated but different plant communities show that functional groups do not predict individual species responses to simulated global change, and that these responses depend to a large extent on pre-existing physical conditions as well as biotic interactions such as competition and facilitation. It may be difficult to apply general trends of global change responses to specific local communities. Copyright: © 2015 Little et al.

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