| 1. |
- During, Heinjo J, et al.
(författare)
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Biomechanical properties of the terrestrial mosses Pleurozium schreberi (Brid.) Mitt. and Pogonatum japonicum Sull. & Lesq. along altitudinal gradients in northern Japan
- 2015
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Ingår i: Arctoa. - : KMK Scientific Press Ltd.. - 0131-1379. ; 24, s. 375-381
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 2. |
- Jägerbrand, Annika K, 1972-, et al.
(författare)
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Effects of simulated shade on growth, number of branches and biomass in Hylocomium splendens and Racomitrium lanuginosum
- 2005
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Ingår i: Lindbergia. - 0105-0761 .- 2001-5909. ; 30:3, s. 117-124
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Tidskriftsartikel (refereegranskat)abstract
- The effects of simulated shade in terms of reduced light quantity (PPFD) and changed red:far-red ratio (R:FR ratio) on the growth in length, in number of branches and in biomass, were examined in a greenhouse experiment with Hylocomium splendens and Racomitrium lanuginosum, two species from habitats with different light conditions (with H. splendens often in more shaded microsites). Using ten intact moss turfs per species which had been collected on Iceland at 4 m distance between replicate turfs, we tested, whether light quantity affected growth and biomass, whether changes in light quantity and red:far-red ratio affected the number of branches, and whether the two species differed in these responses. Reduced light quantity (i.e. PPFD level) caused a greater length increase, decreased biomass, and biomass:length ratio in both species, but the magnitude of response varied greatly between species. Furthermore, in R. lanuginosum spectral shade (i.e. reduced PPFD and a lower R:FR ratio) generally caused stronger responses than neutral shade, with only a reduction in PPFD. H. splendens (from the shaded habitat) responded less strongly to the shade treatments than R. lanuginosum (from the open habitat) did. In addition to these effects of shading, there were strong effects of the turf of origin in both species, and in many cases the interaction between turf of origin and shading treatment was significant as well. Copyright © Lindbergia 2006.
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| 3. |
- Lett, Signe, et al.
(författare)
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Can bryophyte groups increase functional resolution in tundra ecosystems?
- 2022
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Ingår i: Arctic Science. - Ottawa : Canadian Science Publishing. - 2368-7460. ; 8:3, s. 609-637
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Tidskriftsartikel (refereegranskat)abstract
- The relative contribution of bryophytes to plant diversity, primary productivity, and ecosystem functioning increases towards colder climates. Bryophytes respond to environmental changes at the species level, but because bryophyte species are relatively difficult to identify, they are often lumped into one functional group. Consequently, bryophyte function remains poorly resolved. Here, we explore how higher resolution of bryophyte functional diversity can be encouraged and implemented in tundra ecological studies. We briefly review previous bryophyte functional classifications and the roles of bryophytes in tundra ecosystems and their susceptibility to environmental change. Based on shoot morphology and colony organization, we then propose twelve easily distinguishable bryophyte functional groups. To illustrate how bryophyte functional groups can help elucidate variation in bryophyte effects and responses, we compiled existing data on water holding capacity, a key bryophyte trait. Although plant functional groups can mask potentially high interspecific and intraspecific variability, we found better separation of bryophyte functional group means compared with previous grouping systems regarding water holding capacity. This suggests that our bryophyte functional groups truly represent variation in the functional roles of bryophytes in tundra ecosystems. Lastly, we provide recommendations to improve the monitoring of bryophyte community changes in tundra study sites.
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