| 1. |
- Hintz, William D., et al.
(författare)
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Current water quality guidelines across North America and Europe do not protect lakes from salinization
- 2022
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 119:9
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Tidskriftsartikel (refereegranskat)abstract
- Human-induced salinization caused by the use of road deicing salts, agricultural practices, mining operations, and climate change is a major threat to the biodiversity and functioning of freshwater ecosystems. Yet, it is unclear if freshwater ecosystems are protected from salinization by current water quality guidelines. Leveraging an experimental network of land-based and in-lake mesocosms across North America and Europe, we tested how salinization—indicated as elevated chloride (Cl−) concentration—will affect lake food webs and if two of the lowest Cl− thresholds found globally are sufficient to protect these food webs. Our results indicated that salinization will cause substantial zooplankton mortality at the lowest Cl− thresholds established in Canada (120 mg Cl−/L) and the United States (230 mg Cl−/L) and throughout Europe where Cl− thresholds are generally higher. For instance, at 73% of our study sites, Cl− concentrations that caused a ≥50% reduction in cladoceran abundance were at or below Cl− thresholds in Canada, in the United States, and throughout Europe. Similar trends occurred for copepod and rotifer zooplankton. The loss of zooplankton triggered a cascading effect causing an increase in phytoplankton biomass at 47% of study sites. Such changes in lake food webs could alter nutrient cycling and water clarity and trigger declines in fish production. Current Cl− thresholds across North America and Europe clearly do not adequately protect lake food webs. Water quality guidelines should be developed where they do not exist, and there is an urgent need to reassess existing guidelines to protect lake ecosystems from human-induced salinization.
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| 2. |
- Arnott, Shelley E., et al.
(författare)
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Widespread variation in salt tolerance within freshwater zooplankton species reduces the predictability of community-level salt tolerance
- 2023
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Ingår i: Limnology and Oceanography Letters. - : John Wiley & Sons. - 2378-2242. ; 8:1, s. 8-18
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Tidskriftsartikel (refereegranskat)abstract
- The salinization of freshwaters is a global threat to aquatic biodiversity. We quantified variation in chloride (Cl-) tolerance of 19 freshwater zooplankton species in four countries to answer three questions: (1) How much variation in Cl- tolerance is present among populations? (2) What factors predict intraspecific variation in Cl- tolerance? (3) Must we account for intraspecific variation to accurately predict community Cl- tolerance? We conducted field mesocosm experiments at 16 sites and compiled acute LC(50)s from published laboratory studies. We found high variation in LC(50)s for Cl- tolerance in multiple species, which, in the experiment, was only explained by zooplankton community composition. Variation in species-LC50 was high enough that at 45% of lakes, community response was not predictable based on species tolerances measured at other sites. This suggests that water quality guidelines should be based on multiple populations and communities to account for large intraspecific variation in Cl- tolerance.
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| 3. |
- Hebert, Marie-Pier, et al.
(författare)
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Lake salinization drives consistent losses of zooplankton abundance and diversity across coordinated mesocosm experiments
- 2023
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Ingår i: Limnology and Oceanography Letters. - : John Wiley & Sons. - 2378-2242. ; 8:1, s. 19-29
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Tidskriftsartikel (refereegranskat)abstract
- Human-induced salinization increasingly threatens inland waters; yet we know little about the multifaceted response of lake communities to salt contamination. By conducting a coordinated mesocosm experiment of lake salinization across 16 sites in North America and Europe, we quantified the response of zooplankton abundance and (taxonomic and functional) community structure to a broad gradient of environmentally relevant chloride concentrations, ranging from 4 to ca. 1400 mg Cl- L-1. We found that crustaceans were distinctly more sensitive to elevated chloride than rotifers; yet, rotifers did not show compensatory abundance increases in response to crustacean declines. For crustaceans, our among-site comparisons indicate: (1) highly consistent decreases in abundance and taxon richness with salinity; (2) widespread chloride sensitivity across major taxonomic groups (Cladocera, Cyclopoida, and Calanoida); and (3) weaker loss of functional than taxonomic diversity. Overall, our study demonstrates that aggregate properties of zooplankton communities can be adversely affected at chloride concentrations relevant to anthropogenic salinization in lakes.
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| 4. |
- Beisner, Beatrix E., et al.
(författare)
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The role of environmental and spatial processes in structuring lake communities from bacteria to fish
- 2006
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Ingår i: Ecology. - 0012-9658 .- 1939-9170. ; 87:12, s. 2985-2991
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Tidskriftsartikel (refereegranskat)abstract
- We assessed the relative roles of local environmental conditions and dispersal on community structure in a landscape of lakes for the major trophic groups. We use taxonomic presence–absence and abundance data for bacteria, phytoplankton, zooplankton, and fish from 18 lakes in southern Quebec, Canada. The question of interest was whether communities composed of organisms with more limited dispersal abilities, because of size and life history (zooplankton and fish) would show a different effect of lake distribution than communities composed of good dispersers (bacteria and phytoplankton). We examine the variation in structure attributable to local environmental (i.e., lake chemical and physical variables) vs. dispersal predictors (i.e., overland and watercourse distances between lakes) using variation partitioning techniques. Overall, we show that less motile species (crustacean zooplankton and fish) are better predicted by spatial factors than by local environmental ones. Furthermore, we show that for zooplankton abundances, both overland and watercourse dispersal pathways are equally strong, though they may select for different components of the community, while for fish, only watercourses are relevant dispersal pathways. These results suggest that crustacean zooplankton and fish are more constrained by dispersal and therefore more likely to operate as a metacommunity than are bacteria and phytoplankton within this studied landscape.
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| 5. |
- Herzog, Laura, et al.
(författare)
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Studying human-nature relations in aquatic social-ecological systems using the social-ecological action situations framework : how to move from empirical data to conceptual models
- 2022
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Ingår i: Ecology & Society. - 1708-3087. ; 27:3
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Tidskriftsartikel (refereegranskat)abstract
- Various analytical frameworks have been developed to examine the interactions between humans and nature in social-ecological systems (SES). When studies of SES do not make explicit how a framework is used to build conceptual models, they leave a black box for scholars aiming to use such frameworks. Our study highlights such a process, focusing on the analytical step of transitioning from empirical data to categories of the recently developed social-ecological action situations (SE-AS) framework. This framework, which proposes to study SES along configurations of action situations (AS), has so far been applied in few studies. Clarifying how data are analyzed and adapted within this framework is thus of relevance for anyone interested in using it. We compare two analytical methods used to identify AS configurations, each method serving for the analysis of one of two lake-catchment areas, located in Northern Germany and Canada. The first method is a qualitative interview content analysis based on text coding; the second is the analysis of causal loop diagrams (CLD) derived from interviews. Both data sources outline stakeholder social representations of their SES. We compare: (1) the suitability of the two analytical methods for identifying configurations of AS and their linkages, and (2) the potential and limitations of the SE-AS framework for assessing the inherent dynamics of emergent phenomena within SES. Our two-pronged data analysis methodology led to similar results despite the different analytical methods used. We conclude that the SE-AS framework can help illustrate different interactions within an SES while allowing for relatively simple, yet comprehensible system representations. We also identify challenges and limitations that we encountered. Challenges revolve around identifying AS and differentiating them from outcomes. Limitations include the representation of time and levels of governance, and weighting the relative importance of AS.
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| 6. |
- Tanguay, Louis, et al.
(författare)
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Opportunities for and barriers to anticipatory governance of two lake social–ecological systems in Germany and Canada
- 2023
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Ingår i: People and Nature. - 2575-8314. ; 5:3, s. 911-928
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Tidskriftsartikel (refereegranskat)abstract
- Climate change effects are already being felt around the globe, and governance systems need to adapt to this new reality to foster greater resilience in social–ecological systems (SES). Anticipatory governance is a concept proposed for such a purpose. However, its definition remains rather vague in the literature, as is its practical use for decision makers. In this paper, we contribute to filling these two shortcomings.First, we conducted a systematic literature review of the concept and derived the following main criteria: foresight, networked engagement, integration and feedback. Second, we use the identified criteria to analyse two social–ecological systems around lakes in Lower Saxony, Germany and in Quebec, Canada.In both cases, data were generated using a participatory approach (interviews and workshops) with local stakeholders. We examined these data, identifying opportunities and barriers to anticipatory governance. Our findings support, with empirical data for the first time, the claim in the literature that ensemble-ization—the fact that all anticipatory governance criteria must be put forward jointly and not in isolation—is a facilitator for the emergence of anticipation.Furthermore, by highlighting opportunities and barriers to anticipatory governance within two temperate lake SES cases, we illustrate how to understand a given system's limitations with respect to anticipatory governance, as well as how to engage with the concept through concrete, already existing opportunities. The proposed course of actions could help design more anticipatory governance systems to support decision-making processes that could enhance SES resilience.
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