| 1. |
- Cazelles, Kevin, et al.
(author)
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Homogenization of freshwater lakes : Recent compositional shifts in fish communities are explained by gamefish movement and not climate change
- 2019
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In: Global Change Biology. - : John Wiley & Sons. - 1354-1013 .- 1365-2486. ; 25:12, s. 4222-4233
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Journal article (peer-reviewed)abstract
- Globally, lake fish communities are being subjected to a range of scale-dependent anthropogenic pressures, from climate change to eutrophication, and from overexploitation to species introductions. As a consequence, the composition of these communities is being reshuffled, in most cases leading to a surge in taxonomic similarity at the regional scale termed homogenization. The drivers of homogenization remain unclear, which may be a reflection of interactions between various environmental changes. In this study, we investigate two potential drivers of the recent changes in the composition of freshwater fish communities: recreational fishing and climate change. Our results, derived from 524 lakes of Ontario, Canada sampled in two periods (1965-1982 and 2008-2012), demonstrate that the main contributors to homogenization are the dispersal of gamefish species, most of which are large predators. Alternative explanations relating to lake habitat (e.g., area, phosphorus) or variations in climate have limited explanatory power. Our analysis suggests that human-assisted migration is the primary driver of the observed compositional shifts, homogenizing freshwater fish community among Ontario lakes and generating food webs dominated by gamefish species.
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| 2. |
- Kadoya, Taku, et al.
(author)
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Common processes drive metacommunity structure in freshwater fish
- 2024
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In: Global Ecology and Biogeography. - : John Wiley & Sons. - 1466-822X .- 1466-8238. ; 33:5, s. 1-14
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Journal article (peer-reviewed)abstract
- Aim: Environmental change affects metacommunity structure both directly—via abiotic factors and dispersal that affect species occurrence—and indirectly—via complex interactions among co-occurring species. We examined how the three main metacommunity factors—environmental conditions, spatial processes and species associations—affect metacommunity structure and whether responses are predictable in real-world systems by using novel methods to disentangle the drivers.Location: Eastern Asia, northern Europe and central North America.Time period: Contemporary.Major taxa studied: Freshwater fish. Methods: We used a dataset of freshwater fish species occurrences in temperate lakes in three countries in different biogeographic regions. We analysed co-occurrence patterns by using a joint species distribution model.Results: We demonstrated that environmental processes are the main drivers of species' distribution and diversity, suggesting that future climate change (anthropogenic alteration of abiotic factors) will heavily influence the structure of metacommunities. We also showed that spatial processes and species interactions mediated the influence of environmental processes, especially at the lake level.Main conclusions: Our results indicate that ongoing changes in metacommunity structure are modulated not only by the direct impacts of shifting abiotic factors but also by indirect effects of species interactions. Our global analysis indicates that even under the current high rate of environmental change, an identifiable set of underlying processes can be used to predict impacts of this change on metacommunity structure.
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| 3. |
- MacDougall, Andrew S., et al.
(author)
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Comparison of the distribution and phenology of Arctic Mountain plants between the early 20th and 21st centuries
- 2021
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In: Global Change Biology. - : John Wiley & Sons. - 1354-1013 .- 1365-2486. ; 27:20, s. 5070-5083
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Journal article (peer-reviewed)abstract
- Arctic plants are adapted to climatic variability, but their long-term responses to warming remain unclear. Responses may occur by range shifts, phenological adjustments in growth and reproduction, or both. Here, we compare distribution and phenology of 83 arctic and boreal mountain species, sampled identically in the early 20th (1917-1919) and 21st centuries (2017-2018) from a region of northern Sweden that has warmed significantly. We test two compensatory hypotheses to high-latitude warming-upward shifts in distribution, and earlier or extended growth and reproduction. For distribution, we show dramatic upward migration by 69% of species, averaging 6.1 m per decade, especially boreal woodland taxa whose upward expansion has reduced arctic montane habitat by 30%. Twenty percent of summit species showed distributional shifts but downward, especially moisture-associated snowbed flora. For phenology, we detected wide inter-annual variability in the onset of leafing and flowering in both eras. However, there was no detectable change in growing-season length, relating to two mechanisms. First, plot-level snow melt data starting in 1917 demonstrated that melt date, rather than vernal temperatures, better predicts plant emergence, with snow melt influenced by warmer years having greater snowfall-warmer springs did not always result in earlier emergence because snowbeds can persist longer. Second, the onset of reproductive senescence between eras was similar, even when plant emergence was earlier by a month, possibly due to intensified summer heat stress or hard-wired 'canalization' where senescence occurs regardless of summer temperature. Migrations in this system have possibly buffered arctic species against displacement by boreal expansion and warming, but ongoing temperature increases, woody plant invasion, and a potential lack of flexibility in timing of senescence may foreshadow challenges.
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| 4. |
- MacDougall, Andrew S., et al.
(author)
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Context-dependent interactions and the regulation of species richness in freshwater fish
- 2018
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In: Nature Communications. - : Nature Publishing Group. - 2041-1723. ; 9
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Journal article (peer-reviewed)abstract
- Species richness is regulated by a complex network of scale-dependent processes. This complexity can obscure the influence of limiting species interactions, making it difficult to determine if abiotic or biotic drivers are more predominant regulators of richness. Using integrative modeling of freshwater fish richness from 721 lakes along an 11 degrees latitudinal gradient, we find negative interactions to be a relatively minor independent predictor of species richness in lakes despite the widespread presence of predators. Instead, interaction effects, when detectable among major functional groups and 231 species pairs, were strong, often positive, but contextually dependent on environment. These results are consistent with the idea that negative interactions internally structure lake communities but do not consistently 'scale-up' to regulate richness independently of the environment. The importance of environment for interaction outcomes and its role in the regulation of species richness highlights the potential sensitivity of fish communities to the environmental changes affecting lakes globally.
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| 5. |
- Ochoa-Hueso, Raúl, et al.
(author)
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Microbial processing of plant remains is co-limited by multiple nutrients in global grasslands
- 2020
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In: Global Change Biology. - : John Wiley & Sons. - 1354-1013 .- 1365-2486. ; 26:8, s. 4572-4582
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Journal article (peer-reviewed)abstract
- Microbial processing of aggregate-unprotected organic matter inputs is key for soil fertility, long-term ecosystem carbon and nutrient sequestration and sustainable agriculture. We investigated the effects of adding multiple nutrients (nitrogen, phosphorus and potassium plus nine essential macro- and micro-nutrients) on decomposition and biochemical transformation of standard plant materials buried in 21 grasslands from four continents. Addition of multiple nutrients weakly but consistently increased decomposition and biochemical transformation of plant remains during the peak-season, concurrent with changes in microbial exoenzymatic activity. Higher mean annual precipitation and lower mean annual temperature were the main climatic drivers of higher decomposition rates, while biochemical transformation of plant remains was negatively related to temperature of the wettest quarter. Nutrients enhanced decomposition most at cool, high rainfall sites, indicating that in a warmer and drier future fertilized grassland soils will have an even more limited potential for microbial processing of plant remains.
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| 6. |
- Van Der Laan, Eveline A.N.Zeeuw, et al.
(author)
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Biological and structural characterization of murine TRALI antibody reveals increased Fc-mediated complement activation
- 2020
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In: Blood Advances. - : American Society of Hematology. - 2473-9529 .- 2473-9537. ; 4:16, s. 3875-3885
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Journal article (peer-reviewed)abstract
- Transfusion-related acute lung injury (TRALI) remains a leading cause of transfusionrelated deaths. In most cases, anti-leukocyte antibodies in the transfusion product trigger TRALI, but not all anti-leukocyte antibodies cause TRALI. It has been shown that the anti-major histocompatibility complex (MHC) class I antibody 34-1-2S (anti-H-2Kd) causes TRALI in BALB/c mice (MHC class I haplotype H-2Kd), whereas SF1.1.10 (anti-H-2Kd) does not. In C57BL/6 mice (MHC class I haplotype H-2Kb), TRALI only occurs when anti-MHC class I antibody AF6-88.5.5.3 (anti-H-2Kb) is administered together with a high dose of 34-1-2S. It remains unknown which specific antibody characteristics are responsible for eliciting TRALI. We therefore investigated several biological and structural features of 34-1-2S compared with other anti-MHC class I antibodies, which on their own do not cause TRALI: SF1.1.10 and AF6-88.5.5.3. No substantial differences were observed between the TRALIcausing 34-1-2S and the TRALI-resistant SF1.1.10 regarding binding affinity to H-2Kd. Regarding binding affinity to H-2Kb, only AF6-88.5.5.3 potently bound to H-2Kb, whereas 34-1-2S exhibited weak but significant cross-reactivity. Furthermore, the binding affinity to FcgRs as well as the Fc glycan composition seemed to be similar for all antibodies. Similar Fc glycosylation profiles were also observed for human TRALI-causing donor anti-HLA antibodies compared with human anti-HLA antibodies from control donors. 34-1-2S, however, displayed superior complement activation capacity, which was fully Fc dependent and not significantly dependent on Fc glycosylation. We conclude that TRALI induction is not correlated with Fab- A nd Fc-binding affinities for antigen and FcgRs, respectively, nor with the composition of Fc glycans; but increased Fc-mediated complement activation is correlated with TRALI induction.
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