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- Agstam-Norlin, O., et al.
(author)
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A 25-year retrospective analysis of factors influencing success of aluminum treatment for lake restoration
- 2021
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In: Water Research. - : Elsevier BV. - 0043-1354 .- 1879-2448. ; 200
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Journal article (peer-reviewed)abstract
- For more than 50 years, aluminum (Al)-salts have been used with varying degrees of success to inactivate excess mobile phosphorus (P) in lake sediments and restore lake water quality. Here, we analyzed the factors influencing effectiveness and longevity of Al-treatments performed in six Swedish lakes over the past 25 years. Trends in post-treatment measurements of total phosphorus (TP), Chlorophyll a (Chl_a), Secchi disk depth (SD) and internal P loading rates (Li) were analyzed and compared to pre-treatment conditions. All measured water quality parameters improved significantly during at least the first 4 years post-treatment and determination of direct effects of Al-treatment on sediment P release (Li) was possible for three lakes. Improvements in TP (-29 to -80%), Chl_a (-50 to -78%), SD (7 to 121%) and Li (-68 to -94%) were observed. Treatment longevity, determined via decreases in surface water TP after treatment, varied from 7 to >47 years. Lake type, Al dose, and relative watershed area were related to longevity. In addition, greater binding efficiency between Al and P was positively related to treatment longevity, which has not previously been shown. Our findings also demonstrate that adequate, long-term monitoring programs, including proper determination of external loads, are crucial to document the effect of Al-treatment on sediment P release and lake water quality.
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| 2. |
- Smedmark, Jenny E. E., et al.
(author)
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A Phylogeny of Urophylleae (Rubiaceae) based on rps16 intron data
- 2008
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In: Taxon. - 0040-0262. ; 57:1, s. 24-32
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Journal article (peer-reviewed)abstract
- This is the first study of phylogenetic relationships within the pantropical group Urophylleae. Previous studies have included few representatives from this group and little is known about its phylogeny. Here we use sequence data from the rps16 intron to address the question of where the four genera Temnopteryx, Pentaloncha, Pleiocarpidia, and Poecilocalyx, which have sometimes been classified in this group belong. By using different outgroups we show that there is conflict regarding the resolution among lineages in Rubioideae, which partly affects the support for relationships within Urophylleae. Urophylleae is shown to consist of two sister groups, one larger consisting only of Old World taxa and one smaller including the New World genera Amphidasya and Raritebe, and as sister of these two groups the African monotypic genus Temnopteryx. Pentaloncha, Pleiocarpidia, and Poecilocalyx all belong in the large Old World clade, which only comprises taxa included in the original circumscription of Urophylleae. Relationships within this group are not completely resolved, but Poecilocalyx is found to be the sister of Stelechantha and Pleiocarpidia to be the sister of Urophyllum leucophleum. Urophyllum is paraphyletic, as it seems to include Maschalocorymbus, Pleiocarpidia, Praravinia, and Pravinaria. It is not clear from the present analysis whether Pauridiantha is monophyletic or not.
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| 3. |
- Berendse, F, et al.
(author)
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Raised atmospheric CO2 levels and increased N deposition cause shifts in plant species composition and production in Sphagnum bogs
- 2001
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In: Global Change Biology. - : Wiley. - 1354-1013 .- 1365-2486. ; 7:5, s. 591-598
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Journal article (peer-reviewed)abstract
- Part of the missing sink in the global CO2 budget has been attributed to the positive effects of CO2 fertilization and N deposition on carbon sequestration in Northern Hemisphere terrestrial ecosystems. The genus Sphagnum is one of the most important groups of plant species sequestrating carbon in temperate and northern bog ecosystems, because of the low decomposability of the dead material it produces. The effects of raised CO2 and increased atmospheric N deposition on growth of Sphagnum and other plants were studied in bogs at four sites across Western Europe. Contrary to expectations, elevated CO2 did not significantly affect Sphagnum biomass growth. Increased N deposition reduced Sphagnum mass growth, because it increased the cover of vascular plants and the tall moss Polytrichum strictum. Such changes in plant species composition may decrease carbon sequestration in Sphagnum-dominated bog ecosystems.
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| 9. |
- Fonturbel, Francisco E., et al.
(author)
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Cryptic interactions revisited from ecological networks : Mosses as a key link between trees and hummingbirds
- 2021
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In: Functional Ecology. - : John Wiley & Sons. - 0269-8463 .- 1365-2435. ; 35:1, s. 226-238
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Journal article (peer-reviewed)abstract
- Ecological interactions are the glue of biodiversity, structuring communities and determining their functionality. However, our knowledge about ecological interactions is usually biased against cryptic interactions (i.e. overlooked interactions involving inconspicuous species). Mosses are a neglected component in community ecology despite being diverse and abundant in boreal and temperate forests. Therefore, the cryptic relationships of trees as hosts for epiphytic mosses, and vertebrates using mosses as nesting material, may have important consequences for community structuring. We built species- and individual-based ecological networks to characterise tree-moss associations in 120 tree individuals representing 13 species, which hosted 19 moss species. We also used those ecological networks to simulate the effects of non-random extinctions due to selective logging, to assess the presence of moss species in hummingbird nests (30 nests), whether these mosses were a subset of those found on the trees if moss diversity varies with tree height and whether these moss-tree relationships are phylogenetically constrained. We found a nested pattern in the tree-moss network. Taller trees were the most connected, with tree height positively related to number of moss species, network degree and centrality. Extinction simulations showed changes in network topology, with the strongest effect from the removal of the most connected tree species. However, tree and moss networks were not influenced by phylogenetic relatedness. The hummingbirdSephanoides sephaniodesselectively collected mosses; the moss species used as nesting material by hummingbirds were a subset of available species. These complex relationships among trees, birds and mosses underpin the importance of neglected components in the community. We found that tree-moss associations were non-random, showing a positive relationship between tree height and moss diversity. Those associations are the reflection of preferences beyond relative abundances in the forest, and the removal of certain tree species (due to selective logging) may have cascade effects in the community. Furthermore, the lack of phylogenetic correspondence suggests that tree-moss associations are governed by ecological factors (host tree preferences). Moss-hummingbird associations are non-random, as hummingbirds (that pollinate these trees) are actively selecting mosses for nest building, stressing the importance of cryptic interactions as a community-structuring process. A freePlain Language Summarycan be found within the Supporting Information of this article.
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| 10. |
- Granath, Gustaf, et al.
(author)
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Tradeoffs and scaling of functional traits in Sphagnum as drivers of carbon cycling in peatlands
- 2014
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In: Oikos. - : Wiley. - 0030-1299 .- 1600-0706. ; 123:7, s. 817-828
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Journal article (peer-reviewed)abstract
- Growth and decomposition of Sphagnum controls turnover of a large global store of soil organic carbon. We investigated variation in morphological and physiological traits of Sphagnum shoots, and related this variation to canopy variables relevant to peatland carbon cycling. We sampled Sphagnum along a bog plateau-swamp forest gradient and measured a suite of shoot traits and canopy variables. Major axes of variation were identified using principal component analysis and correlated with canopy variables such as growth, biomass and decomposition. We also examined scaling of shoot traits with one another and with canopy variables. Two distinct tradeoffs in shoot traits emerged. From dry to wet habitats, individual metabolic rates and capitulum size increased while numerical density decreased, leading to faster growth and elongation on an individual basis. From treed to open habitats, photosynthetic efficiency decreased and photosynthetic biomass increased, driving faster growth on an area basis and slower litter mass loss. The tradeoffs identified have important implications for peatlands undergoing climate-related changes in water and light availability. Sphagnum trait comparisons, combined with scaling analyses, offer a promising approach to understanding and predicting the effects of environmental change on peatland carbon cycling.
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