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- Tyler, Torbjörn, et al.
(author)
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Nu startar projekt Skånes Mossor!
- 2007
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In: Botaniska Notiser. - 0006-8195. ; 140:2, s. 1-6
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Journal article (peer-reviewed)abstract
- The Lund Botanical Society 2007-03-23 decided to launch a project with the following aims: 1) to map the frequency and distribution of all bryophytes in the province of Skåne, southernmost Sweden, thereby making way for future studies of changes in the flora, 2) to find and document as many sites as possible for nationally and regionally rare or endangered bryophytes and initiate conservation actions at these sites, 3) to increase our knowledge of the ecological demands of individual taxa, and 4) to enhance the level of knowledge concerning bryophytes among both amateur botanists and professional nature conservationists. The province has been divided into 534 5 x 5 km grid-squares. The central square kilometre within each grid-square will be surveyed and the result used for unbiased estimates of the frequency of each taxon. In addition, within each grid-square, a variable number of special areas which may be presumed to have a rich or unusual bryophyte flora have been preselected for the survey. Additional areas may be selected by the recorders themselves, but the ultimate goal is not to survey the grid-square as a whole. A special determination key and nomenclatural check-list to all 658 taxa hithereto known from the province, as well as various instructions and forms for the volonteer recorders, have been made available on the Internet and a central database with an Internet interface is under way. Various kinds of courses have been initiated with the aim of educating future recorders. The aim is to survey all grid-squares during a 20 year period and the project is now calling for support from bryologists world-wide.
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- Tyler, Torbjörn, et al.
(author)
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Projekt Skånes Mossor 2008-2013 - en deltidsrapport
- 2014
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In: Nordic Journal of Botany. - 0107-055X. ; 147:2, s. 1-32
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Journal article (peer-reviewed)abstract
- About 25% of the 531 5x5 km grid squares have been investigated during the six first years of the ongoing survey of the bryophyte flora of the province of Skåne, c. 50 persons have participated and 65,539 records and 21,135 vouchers have been collected. Of the 687 taxa that have ever been reported from the province, 591 have been recorded since 1995 and 34 have been found as new to the province since then. In this part-time report, the records and our present knowledge about each taxon ever found in the province are briefly summarized and it is concluded that our knowledge of the bryophyte flora of the province has increased multifold during these six years of intense surveying.
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- Bengtsson, Bengt Olle, et al.
(author)
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The effective size of bryophyte populations.
- 2009
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In: Journal of Theoretical Biology. - : Elsevier BV. - 1095-8541 .- 0022-5193. ; 258:Available online 8 January 2009, s. 121-126
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Journal article (peer-reviewed)abstract
- Bryophytes with their dominant haploid stage conform poorly to the life cycles generally treated in population genetical models. Here we make a detailed analysis of what effective sizes bryophyte model populations have as a function of their breeding system. It is found that the effective size is rarely much smaller than the scored number of haploid gametophytic individuals, even when the limited number of diploids (sporophytes) formed is taken into account. The most severe decrease in effective size occurs when unisexual gametophytic females produce only a small number of fertile diploid sporophytes in male biased populations; this effect is due to the restricted sampling of male gametophytic individuals that then occurs. It is shown that the harmonic mean of diploid sporophytes formed per haploid gametophytic individuals is the relevant measure in these calculations and not the standard (and generally larger) arithmetic mean.
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- Bengtsson, Fia, 1986-
(author)
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Functional Traits in Sphagnum
- 2019
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Doctoral thesis (other academic/artistic)abstract
- Peat mosses (Sphagnum) are ecosystem engineers that largely govern carbon sequestration in northern hemisphere peatlands. I investigated functional traits in Sphagnum species and addressed the questions: (I) Are growth, photosynthesis and decomposition and the trade-offs between these traits related to habitat or phylogeny?, (II) Which are the determinants of decomposition and are there trade-offs between metabolites that affect decomposition?, (III) How do macro-climate and local environment determine growth in Sphagnum across the Holarctic?, (IV) How does N2 fixation vary among different species and habitats?, (V) How do species from different microtopographic niches avoid or tolerate desiccation, and are leaf and structural traits adaptations to growth high above the water table?Photosynthetic rate and decomposition in laboratory conditions (innate growth and decay resistance) were related to growth and decomposition in their natural habitats. We found support for a trade-off between growth and decay resistance, but innate qualities translated differently to field responses in different species. There were no trade-offs between production of different decay-affecting metabolites. Their production is phylogenetically controlled, but their effects on decay are modified by nutrient availability in the habitat. Modelling growth of two species across the Holarctic realm showed that precipitation, temperature and vascular plant cover are the best predictors of performance, but responses were stronger for the wetter growing species. N2 fixation rates were positively related to moss decomposability, field decomposition and tissue phosphorus concentration. Hence, higher decomposition can lead to more nutrients available to N2-fixing microorganisms, while higher concentrations of decomposition-hampering metabolites may impede N2 fixation. A mesocosm experiment, testing effects of water level drawdown on water content and chlorophyll fluorescence, showed that either slow water loss or high maximum water holding capacity can lead to desiccation avoidance. Furthermore, leaf anatomical traits rather than structural traits affected the water economy.This thesis has advanced the emerging field of trait ecology in Sphagnum by comparing many species and revealing novel mechanisms and an ever more complex picture of Sphagnum ecology. In addition, the species-specific trait measurements of this work offers opportunities for improvements of peatland ecosystem models.
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- Bengtsson, Fia, et al.
(author)
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Mechanisms behind species-specific water economy responses to water level drawdown in peat mosses
- 2020
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In: Annals of Botany. - : Oxford University Press (OUP). - 0305-7364 .- 1095-8290. ; 126:2, s. 219-230
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Journal article (peer-reviewed)abstract
- Background and AimsThe ecosystem engineers Sphagnum (peat mosses) are responsible for sequestering a large proportion of carbon in northern peatlands. Species may respond differently to hydrological changes, and water level changes may lead to vegetation shifts in peatlands, causing them to revert from sinks to sources of carbon. We aimed to compare species-specific responses to water level drawdown within Sphagnum, and investigate which traits affect water economy in this genus.MethodsIn a mesocosm experiment, we investigated how water level drawdown affected water content (WC) in the photosynthetically active apex of the moss and maximum quantum yield of photosystem II (i.e. Fv/Fm) of 13 Sphagnum species. Structural traits were measured, and eight anatomical traits were quantified from scanning electron microscopy micrographs.Key ResultsMixed-effects models indicated that at high water level, large leaves were the most influential predictor of high WC, and at low water level WC was higher in species growing drier in the field, with larger hyaline cell pore sizes and total pore areas associated with higher WC. Higher stem and peat bulk density increased WC, while capitulum mass per area and numerical shoot density did not. We observed a clear positive relationship between Fv/Fm and WC in wet-growing species.ConclusionsWhile we found that most hummock species had a relatively high water loss resistance, we propose that some species are able to maintain a high WC at drawdown by storing large amounts of water at a high water level. Our result showing that leaf traits are important warrants further research using advanced morphometric methods. As climate change may lead to more frequent droughts and thereby water level drawdowns in peatlands, a mechanistic understanding of species-specific traits and responses is crucial for predicting future changes in these systems.
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- Bisang, Irene, et al.
(author)
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Can the meiotic sex ratio explain the sex ratio bias in adult populations in the dioicous moss Drepanocladus lycopodioides?
- 2017
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In: Journal of Bryology. - : Informa UK Limited. - 0373-6687 .- 1743-2820. ; 39:2, s. 115-120
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Journal article (peer-reviewed)abstract
- Sex ratio variation is commonly observed in natural populations of many organisms with separate sexes and genetic sex determination, including bryophytes. Most bryophyte populations exhibit female-skewed expressed adult sex ratios, generally inferred from counts of sexually mature plants. For the rarely sexually reproducing perennial dioicous moss Drepanocladus lycopodioides, we showed that a female bias also exists in the genetic adult sex ratio, using a specifically designed molecular sex-associated marker. Here, we investigated whether the meiotic spore sex ratio contributes to the observed bias in genetic adult sex ratio in natural populations. Earlier attempts to study meiotic sex ratios have involved commonly cultivated ruderals that rapidly express sex in the laboratory. We established single-spore cultures from field-collected sporophytes from these populations and used the marker to assess the sex of individual sporelings. Spore germinability was (near) complete, and mortality among sporelings was virtually absent. The true meiotic sex ratio did not differ from equality, but strongly differed both from the observed genetic sex ratios in the natural adult populations, and from the European scale genetic sex ratio. We conclude that the biased population sex ratios in this species arise at life cycle stages after spore germination. Sexual dimorphism may selectively favour female proliferation during some phase of gametophyte development. Based on methodological progress, we successfully used a perennial study species with rare sexual reproduction, which significantly broadens the life history spectrum investigated in bryophyte sex ratio studies.
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