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Objectives: To evaluate the cost‐effectiveness of root canal treatment (RCT) compared with a tooth extraction in a general dental practice setting, with reference to cost per quality‐adjusted life‐year (QALY) gained over 1 year. Material and Methods: This is a prospective controlled cohort study based on patients either starting RCT or undergoing extraction at one of six Public Dental Service clinics in the county of Västra Götaland, Sweden. From a total of 65 patients, 2 comparable groups were formed: 37 started RCT and 28 underwent extraction. A societal perspective was used for the cost calculations. QALYs were estimated, based on the EQ‐5D‐5L given to the patients at their first treatment appointment and then after 1, 6, and 12 months. Results: The total mean cost of RCT ($689.1) was higher than for extraction ($280.1). For those patients whose extracted tooth was replaced, the costs were even higher ($1245.5). There were no significant intergroup differences in QALYs, but a significant improvement in health state values in the tooth‐preserving group. Conclusions: In the short term, extraction was cost‐effective compared with preserving a tooth with RCT. However, the potential need for future replacement of the extracted tooth, by an implant, fixed prosthesis, or removable partial dentures, may change the calculation in favor of RCT. [ABSTRACT FROM AUTHOR]

Macrophyte invasive alien species (IAS) fitness is often hypothesised to be associated with beneficial environmental conditions (environmental matching) or species‐poor communities. However, positive correlations between macrophyte IAS abundance and native plant richness can also arise, due to habitat heterogeneity (defined here as variation in abiotic and native biotic conditions over space and time). We analysed survey and palaeoecological data for macrophytes in satellite lakes along the Upper Lough Erne (ULE) system (Northern Ireland, UK), covering a gradient of eutrophication and connectivity to partition how environmental conditions, macrophyte diversity and habitat heterogeneity explained the abundance of Elodea canadensis, a widely distributed non‐native macrophyte in Europe. E. canadensis abundance positively correlated with macrophyte richness at both the within‐ and between‐lake scales indicating coexistence of native and invasive species over time. E. canadensis was also more prolific in highly connected and macrophyte‐rich lakes, but sparser in the more eutrophic‐isolated ones. Partial boosted regression trees revealed that in eutrophic‐isolated lakes, E. canadensis abundances correlated with water clarity (negatively), plant diversity (positively), and plant cover (negatively) whereas in diverse‐connected lakes, beta diversity (both positively and negatively) related to most greatly E. canadensis abundance. Dense macrophyte cover and unfavourable environmental conditions thus appear to confer invasibility resistance and sufficient habitat heterogeneity to mask any single effect of native biodiversity or environmental matching in controlling E. canadensis abundance. Therefore, in shallow lake landscapes, habitat heterogeneity variously enables the coexistence of native macrophytes and E. canadensis, reducing the often‐described homogenisation effects of invasive macrophytes. [ABSTRACT FROM AUTHOR]

Objectives: Direct cost for methods of prediction also named risk assessment in dentistry may be negligible compared with the cost of extensive constructions. On the other hand, as risk assessment is performed daily and for several patients in general dental practice, the costs may be considerable. The objective was to summarize evidence in studies of economic evaluation of prognostic prediction multivariable models and methods of caries and periodontitis and to identify knowledge gaps (PROSPERO registration number: CRD42020149763). Material and methods: Four electronic databases (PubMed, Web of Science, The Cochrane Library, NHS Economic Evaluation Database) and reference lists of included studies were searched. Titles and abstracts were screened by two reviewers in parallel. Full‐text studies reporting resources used, costs and cost‐effectiveness of prediction models and methods were selected and critically appraised using a protocol based on items from the CHEERS checklist for economic evaluations and the CHARMS checklist for evaluation of prediction studies. Results: From 38 selected studies, six studies on prediction fulfilled the eligibility criteria, four on caries and two on periodontitis. As the economic evaluations differed in method and perspective among the studies, the results could not be generalized. Our systematic review revealed methodological shortcomings regarding the description of predictive models and methods, and particularly of the economic evaluation. Conclusions: The systematic review highlighted a paucity of economic evaluations regarding methods or multivariable models for prediction of caries and periodontitis. Our results indicate that what we currently practice using models and methods to predict caries and periodontitis lacks evidence regarding cost‐effectiveness. [ABSTRACT FROM AUTHOR]

To test hypotheses concerning the applicability of the Rapoport effect (RE: "species that occur at higher latitudes tend to have greater geographical range‐size than species which have ranges limited to latitudes closer to the equator") to aquatic macrophytes at global scale, we analysed the world latitudinal distribution and range‐size of 1,083 vascular aquatic macrophyte species, from 91 genera in 11 families. We targeted macrophyte families strongly associated with inland aquatic habitats (i.e. with a zero, or only very low, proportion of constituent species which occur also in non‐aquatic habitats), and which are distributed across a substantial latitudinal gradient, a necessary condition to test our hypotheses.The macrophyte species present in these families include plants from all the normally accepted life form‐defined functional groups of macrophytes, namely submerged, free‐floating, floating‐leaf rooted and emergent species, and represent the three major vascular taxonomic groups occurring as aquatic macrophytes (ferns/fern allies, monocots, and dicots). For the analysis, we used both latitude‐only and areal measures of macrophyte species geographic range‐size, within a 10 × 10° (latitude × longitude) grid of 238 grid cells, covering the six world ecozones (Palaearctic, Orient, Australasia, Nearctic, Neotropics, Afrotropics) that primarily contain inland freshwater and brackish macrophyte habitats.The results provide new insight into the relationships between global range‐size of macrophytes, latitude, and other potential spatio‐environmental and anthropogenic drivers acting upon these plants at world scale. In particular, the outcomes indicated that: (1) the range‐size versus latitude distribution of macrophytes shows evidence of a strong RE influence, with significantly greater species range‐size at higher latitudes; and (2) the β‐diversity pattern of species distribution along this latitudinal gradient is poorly explained by nestedness organisation, and species turnover is a more likely explanation of the observed changes in species distribution with latitude.Spatio‐environmental and anthropogenic variables other than latitude may also influence the observed global geographical pattern of macrophyte range‐size, although their importance as predictors varies between individual families. Extent of agricultural land use, altitude, and historic (post‐Quaternary) climate change velocity were all significant predictor variables for some families. However, interestingly, neither the area of land nor the area of waterbody present per grid cell were major influences on macrophyte range‐size distribution.Our finding of evidence for an RE, acting at global scale in aquatic macrophytes, contributes to increasing the generality of conclusions so far reached about the large‐scale factors that drive patterns of species range‐size at global scale. The study also provides a baseline for future macroecological work on aquatic plants, and potentially other freshwater organisms, particularly in the context of predicting how the world ranges of freshwater biota will respond to ongoing global environmental change. [ABSTRACT FROM AUTHOR]

Understanding large‐scale migratory behaviours, local movement patterns and population connectivity are critical to determining the natural processes and anthropogenic stressors that influence population dynamics and for developing effective conservation plans. Atlantic tarpon occur over a broad geographic range in the Atlantic Ocean where they support valuable subsistence, commercial and recreational fisheries. From 2001 through 2018, we deployed 292 satellite telemetry tags on Atlantic tarpon in coastal waters off three continents to document: (a) seasonal migrations and regional population connectivity; (b) freshwater and estuarine habitat utilization; (c) spawning locations; and (d) shark predation across the south‐eastern United States, Gulf of Mexico and northern Caribbean Sea. These results showed that some mature tarpon make long seasonal migrations over thousands of kilometres crossing state and national jurisdictional borders. Others showed more local movements and habitat use. The tag data also revealed potential spawning locations consistent with those inferred in other studies from observations of early life stage tarpon leptocephalus larvae. Our analyses indicated that shark predation mortality on released tarpon is higher than previously estimated, especially at ocean passes, river mouths and inlets to bays. To date, there has been no formal stock assessment of Atlantic tarpon, and regional fishery management plans do not exist. Our findings will provide critical input to these important efforts and assist the multinational community in the development of a stock‐wide management information system to support informed decision‐making for sustaining Atlantic tarpon fisheries. [ABSTRACT FROM AUTHOR]

Aim: To investigate if connectivity and zebra mussel (Dreissena polymorpha) occurrence can mitigate effects of eutrophication in a lowland lake landscape. Location: Upper Lough Erne, Northern Ireland, UK. Methods: Data on environment, macrophytes and invertebrates were assembled for three basins of a large central lake and its satellite floodplain lakes via field surveys and palaeolimnological analyses. Space–time interaction analyses of palaeoecological data were compared pre‐1950 and post‐1950. Multivariate analyses examined how connectivity, environment and zebra mussels influenced contemporary lake communities, and explain their divergence from historical communities in the past. Results: Pre‐1950, we found high community variation across sites and low within‐lake variation in macrophytes, but progressive eutrophication accentuated within‐lake community variation after 1950. Partitioning analysis showed larger effects of connectivity than nutrient enrichment on contemporary macrophyte composition, while local effects structured invertebrate communities. Three clusters of lakes were revealed according to variation in macrophyte composition, isolation from the central lake and nutrient enrichment: Group 1– the central lake and six nearby lakes were meso‐eutrophic (TP = 66.7 ± 47.6 μg/L; TN = 0.79 ± 0.41 mg/L) and had the highest zebra mussel abundances and organismal biodiversity; Group 2– Eight eutrophic (TP = 112±36.6 μg/L; TN = 1.25 ± 0.5 mg/L) and connected lakes; Group 3– Seven isolated and hypertrophic (TP = 163.2 ± 101.5 μg/L; TN = 1.55 ± 0.3 mg/L) lakes. Pre‐1950 palaeolimnological data for macrophytes and invertebrates for 5 lakes and a basin in the central lake most resembled extant lake communities of Group 1. However, palaeo‐records revealed that macrophytes and invertebrates subsequently converged towards those of Groups 2 and 3. Main conclusions: Our study reveals that the central "mother" lake acts as a hub for preserving biodiversity via shared hydrological connectivity with satellite lakes and high zebra mussel abundances. These may buffer the impoverishing effects of eutrophication and sustain unexpectedly high biodiversity in the short term. Such protective buffering, however, cannot be relied upon indefinitely to conserve biodiversity. [ABSTRACT FROM AUTHOR]

Background: We have previously reported inconclusive results from a randomized controlled trial in elderly with hip-fracture comparing intra-operative goal-directed therapy with routine fluid treatment. Now we aimed to describe and compare secondary outcomes at 4 months and 1 year follow-up and to analyze the cost-effectiveness.Methods: Patients with hip fracture (age ≥70) were randomized for GDT or routine fluid treatment (RFT). The secondary outcomes were long-term survival, complications, number of hospital readmissions, and quality of life (EQ-5D) changes. Additionally, cost effectiveness was analyzed by an analytic tool which combines the clinical effectiveness, quality of life changes and costs.Results: Patient data (GDT n = 74; RFT n = 75) were analyzed on an intention to treat basis. Statistically significant differences (GDT vs RFT) were not found considering survival (RR 0.76, 95%CI 0.45-1.28) and complications (RR 0.68, 95% CI 0.4-1.10) at 12 months. No statistically significant difference was found between hospital readmissions and quality of life changes.Conclusion: The statistical uncertainty of risk reduction of negative outcomes and the large variability of the collected data indicate the need of further research in large sample sizes. To enable future health economic evaluation for decision support surrounding implementation of GDT, we suggest adding patient-oriented outcomes in future trials. [ABSTRACT FROM AUTHOR]

Objectives: To examine the current knowledge on oral health status and dental care of older persons through a systematic mapping of systematic reviews of low or moderate risk of bias.Background: Geriatric dentistry covers all aspects of oral health and oral care of older persons. Oral health is part of general health and contributes to a person's physical, psychological and social wellbeing.Methods: A literature search was performed in three different databases (PubMed, The Cochrane Library and Cinahl) within 12 domains: Dental caries, periodontitis, Orofacial pain and temporomandibular joint (TMJ) pain, mucosal lesions, oral motor function, dry mouth, halitosis, interaction between oral status and other medical conditions, ability to interrelate and communicate, quality of life, ethics and organisation of dental care for older persons. Systematic reviews were identified and scrutinised, highlighting scientific knowledge and knowledge gaps.Results: We included 32 systematic reviews of which 14 were judged to be of low/moderate risk of bias. Most of the domains lack systematic reviews with low or moderate risk of bias. In two of the domains evidence was identified; in institutionalised people aged 65 or older, effective oral hygiene can prevent pneumonia. Furthermore, there is an evidence of a relationship between malnutrition (protein energy-related malnutrition, PEM) and poor appetite and edentulousness.Conclusions: There is an urgent need for further research and evidence-based knowledge within most domains in geriatric dentistry and in other fields related to oral health and dental care for older persons striving for multi-disciplinary research programmes. [ABSTRACT FROM AUTHOR]

This study assessed the hypothesis that spatial and environmental drivers of river macrophyte diversity and community composition differ in relative importance in calcareous river systems located in warm regions of America versus Africa., We collected aquatic vegetation and spatio-environmental data, during 2006-11, from >200 hardwater rivers, and associated floodplain waterbodies, located up to 30° north or south of the Equator, in México, Trinidad, Brazil, Argentina, U.S.A. (Florida), South Africa, Botswana and Zambia., Species rarefaction procedures were used to assess the impacts of differing sampling effort in the two continents upon estimation of γ-diversity ('species pool'). We then used a cluster analysis approach (two-way indicator species analysis: TWINSPAN) to classify samples into groups based upon species composition. Variation in species richness, community composition and six spatial and environmental variables, among samples making up these groups, were compared using ANOVA and Kruskal-Wallis procedures. Regression trees and redundancy analysis were used to infer the relative importance of spatial and environmental drivers in explaining variation in local species richness and species community composition between the two continents. Sorensen's index ( Cs) was calculated to estimate species turnover (β-diversity) between African and American samples., In total, 378 macrophyte taxa were recorded, with no significant difference in mean macrophyte α-diversity between African and American sites, but with evidence for high species turnover between the two continents ( Cs = 0.17). Rarefaction analysis confirmed the existence of a larger macrophyte species pool in the hardwater rivers sampled in Africa compared to America. TWINSPAN classification identified seven sample end-groups, only one of which contained a mix of sites from both continents. PERMANOVA and non-metric multidimensional scaling ordination analysis confirmed significant differences in community composition present in these sample-groups. There were substantial differences between the sample-groups for α-diversity, and for spatial and environmental variables., The high species turnover between Africa and America may be accounted for by geographical segregation, along with differences in aquatic habitat characteristics, and varying long-distance dispersal capacities of individual species. The relative importance of spatial and physicochemical drivers (latitude, pH, altitude, alkalinity and electrical conductivity but not flow) differed between the continents in influencing variation in both macrophyte diversity and community composition. Latitude was a significant, although nonlinear and rather complex, spatial driver of macrophyte α-diversity in both American and African hardwater rivers. Water chemistry variables varied in relative importance as drivers of macrophyte α-diversity for African and American sites individually, and for all sites combined, but pH and/or electrical conductivity were more important than alkalinity in each case. In all three cases, altitude was consistently the third most important driver of α-diversity. Spatial and environmental variables played important roles in structuring macrophyte community composition in warm-water calcareous rivers in both America and Africa, with latitude being the strongest individual driver. Thus, this spatial variable, which is a surrogate for numerous enviro-climatic variables, appears to be of importance in determining macrophyte distributions at large spatial scales, for the ecosystem type examined here. [ABSTRACT FROM AUTHOR]

Shallow lakes may play an important role for the nitrogen (N) balance in drainage basins by processing, transferring and retaining N inputs. An increase in the frequency of storm-induced short-term N pulses and increased water temperatures are both likely outcomes of climate change, potentially affecting the N processing in lakes., An experiment with a K15 NO3− pulse addition (increase in NO3− concentration from c. 0.1 to 2 mg/L) was carried out in 12 mesocosms with relatively low (applies to Danish lakes) total N ( TN) and total phosphorus ( TP) concentrations ( c. 0.3 mg N L−1 and 0.04 mg P L−1) to assess the effects of an N pulse on N processing and storage in shallow lake ecosystems. The mesocosms have a hydraulic retention time of approximately two and a half months, and at the time of the experiment, they had been adapted to contrasting temperatures for a period of 10 years: ambient, T3 (heating according to the Intergovernmental Panel on Climate Change 2007 A2 scenario, +3.7-4.5°C, depending on season) and T5 (heating with A2 + 50%, +4.9-6.6°C)., Macrophytes and filamentous algae retained up to 40% and 30% of the added 15N, respectively, reflecting their high biomass in the mesocosms. Macrophytes and filamentous algae constituted between 70% and 80% of the biomass of all primary producers during the experiment in the T3 and ambient treatments and between 20% and 40% in T5. By comparison, less than 1% of the added 15N diffused to the sediment and less than 5% was lost to the atmosphere as N2 gas. Snails represented the long-term storage of 15N, retaining up to 6% of the tracer and with detectable enrichment 100 days after tracer addition., We found no significant differences among the temperature treatments in the 15N turnover after pulse dosing. However, a larger percentage of 15N was stored in macrophytes in the ambient and T3 mesocosms, reflecting higher biomasses than in T5 where filamentous algae were more abundant. Macrophytes and filamentous algae rather than temperature were therefore key controllers of N processing during the summer N pulse in these shallow, relatively low TP lakes. [ABSTRACT FROM AUTHOR]

Shallow lakes are a key component of the global carbon cycle. It is, therefore, important to know how shallow lake ecosystems will respond to the current climate change. Global warming affects not only average temperatures, but also the frequency of heat waves (HW). The impact of extreme events on ecosystems processes, particularly greenhouse gas ( GHG) emissions, is uncertain., Using the world's longest-running shallow lake experiment, we studied the effects of a simulated summer HW on the fluxes of carbon dioxide ( CO2), methane ( CH4) and nitrous oxide (N2O). The experimental mesocosms had been exposed to different temperature treatments and nutrient loading for 11 years prior to the artificial HW., In general, there was an increase in total GHG emissions during the 1-month artificial HW, with a significant increase in CO2, CH4 and N2O being observed in the shallow lake mesocosms. No significant effect of the HW on CO2 emissions could be traced, though, in the mesocosms with high nutrient levels. Furthermore, the data suggested that in addition to the direct effect of increased temperature on metabolic processes during the HW, biotic interactions exerted a significant control of GHG emissions. For example, at low nutrient levels, increased CO2 emissions were associated with low macrophyte abundance, whereas at high nutrient levels, decreased phytoplankton abundance was linked to increased emissions of CO2 and CH4., In contrast to the observable heat-wave effect, no clear general effect of the long-term temperature treatments could be discerned over the summer, likely because the potential effects of the moderate temperature increase, applied as a press disturbance, were overridden by biotic interactions. This study demonstrates that the role of biotic interactions needs to be considered within the context of global warming on ecosystem processes. [ABSTRACT FROM AUTHOR]

Introduction: The aim of this study was to review the performance of non-invasive prenatal testing (NIPT) for detection of trisomy 21, 18 and 13 (T21, T18 and T13) in a general pregnant population as well as to update the data on high-risk pregnancies.Material and Methods: Systematic review and meta-analysis. PubMed, Embase and the Cochrane Library were searched. Methodological quality was rated using QUADAS and scientific evidence using GRADE. Summary measures of diagnostic accuracy were calculated using a bivariate random-effects model.Results: In a general pregnant population, there is moderate evidence that the pooled sensitivity is 0.993 (95% CI 0.955-0.999) and specificity was 0.999 (95% CI 0.998-0.999) for the analysis of T21. Pooled sensitivity and specificity for T13 and T18 was not calculated in this population due to the low number of studies. In a high-risk pregnant population, there is moderate evidence that the pooled sensitivities for T21 and T18 are 0.998 (95% CI 0.981-0.999) and 0.977 (95% CI 0.958-0.987) respectively, and low evidence that the pooled sensitivity for T13 is 0.975 (95% CI 0.819-0.997). The pooled specificity for all three trisomies is 0.999 (95% CI 0.998-0.999).Conclusions: This is the first meta-analysis using GRADE that shows that NIPT performs well as a screen for trisomy 21 in a general pregnant population. Although the false positive rate is low compared with first trimester combined screening, women should still be advised to confirm a positive result by invasive testing if termination of pregnancy is under consideration. [ABSTRACT FROM AUTHOR]

One of the most prominent manifestations of the ongoing climate warming is the retreat of glaciers and ice sheets around the world. Retreating glaciers result in the formation of new ponds and lakes, which are available for colonization. The gradual appearance of these new habitat patches allows us to determine to what extent the composition of asexual Daphnia (water flea) populations is affected by environmental drivers vs. dispersal limitation. Here, we used a landscape genetics approach to assess the processes structuring the clonal composition of species in the D. pulex species complex that have colonized periglacial habitats created by ice-sheet retreat in western Greenland. We analysed 61 populations from a young (<50 years) and an old cluster (>150 years) of lakes and ponds. We identified 42 asexual clones that varied widely in spatial distribution. Beta-diversity was higher among older than among younger systems. Lineage sorting by the environment explained 14% of the variation in clonal composition whereas the pure effect of geographical distance was very small and statistically insignificant ( [ABSTRACT FROM AUTHOR]

Fresh waters make a disproportionately large contribution to greenhouse gas ( GHG) emissions, with shallow lakes being particular hot spots. Given their global prevalence, how GHG fluxes from shallow lakes are altered by climate change may have profound implications for the global carbon cycle. Empirical evidence for the temperature dependence of the processes controlling GHG production in natural systems is largely based on the correlation between seasonal temperature variation and seasonal change in GHG fluxes. However, ecosystem-level GHG fluxes could be influenced by factors, which while varying seasonally with temperature are actually either indirectly related (e.g. primary producer biomass) or largely unrelated to temperature, for instance nutrient loading. Here, we present results from the longest running shallow-lake mesocosm experiment which demonstrate that nutrient concentrations override temperature as a control of both the total and individual GHG flux. Furthermore, testing for temperature treatment effects at low and high nutrient levels separately showed only one, rather weak, positive effect of temperature ( CH4 flux at high nutrients). In contrast, at low nutrients, the CO2 efflux was lower in the elevated temperature treatments, with no significant effect on CH4 or N2O fluxes. Further analysis identified possible indirect effects of temperature treatment. For example, at low nutrient levels, increased macrophyte abundance was associated with significantly reduced fluxes of both CH4 and CO2 for both total annual flux and monthly observation data. As macrophyte abundance was positively related to temperature treatment, this suggests the possibility of indirect temperature effects, via macrophyte abundance, on CH4 and CO2 flux. These findings indicate that fluxes of GHGs from shallow lakes may be controlled more by factors indirectly related to temperature, in this case nutrient concentration and the abundance of primary producers. Thus, at ecosystem scale, response to climate change may not follow predictions based on the temperature dependence of metabolic processes. [ABSTRACT FROM AUTHOR]

Highly calcareous (marl) lakes are infrequent but important freshwater ecosystems, protected under the EU Habitats and Species Directive. Chara lakes have been considered resistant to eutrophication owing to the self-stabilising properties of charophyte meadows. However, the opposite is suggested by the large-scale biodiversity declines in marl lake taxa in Europe, and evidence of charophyte sensitivity to eutrophication. We combined contemporary, palaeolimnological and archival methods to investigate the eutrophication of Hawes Water, a shallow marl lake in north-west England ( U.K.)., Changes in aquatic macrophyte and invertebrate communities were reconstructed through the analysis of historical macrophyte surveys and sedimentary plant and animal macrofossils in two dated sediment cores from the littoral and deep zones of the lake. In addition, chlorophyll and carotenoid pigments were analysed to track changes in primary production from benthic and pelagic areas. Substantial changes in macrophyte communities were detected over centennial timescales, suggesting high ecosystem sensitivity considering the presently moderate phosphorus concentrations in Hawes Water (mean annual total phosphorus 20 μg L−1)., Two apparent periods of threshold-like change were identified from the sediment record: (i) changes in cyanobacteria (aphanizophyll + myxoxanthophyll to canthaxanthin + zeaxanthin) and potentially in nutrient stoichiometry, reductions in the maximum macrophyte colonisation depth and water clarity, reduced charophyte and Potamogeton diversity, and increases in Nymphaeaceae; and (ii) severe reductions in light availability inferred from subdecadal doubling in phytoplankton abundance, substantial increases in Daphnia abundance and the extinction of charophytes from higher water depths., Further, change in both the littoral and deeper water has confined key marl lake taxa to smaller niches. In the littoral, increasing siltation and reed and Nymphaeaceae densities caused extinction of Littorella uniflora in the early 1900s and have reduced the evenness of Characeae with suspected imminent extinction of two highly localised Chara spp. In the deeper water, upslope creep of maximum colonisation depth has reduced habitat for intermediate-depth marl lake taxa leading to the loss of four Potamogeton and one Chara species, and replacement of these taxa by Nuphar lutea., The large changes in macrophyte community composition and increased incidences of turbid water have reduced the distinctive and valued marl lake features of Hawes Water, indicating that marl lakes can, as a habitat type, be highly sensitive to eutrophication. The persistence of abundant generalist macrophyte species at considerable water depth may be a feature of high-alkalinity lakes in clearwater, macrophyte-dominated states, but is a distinct eutrophication response in marl lakes rather than an indication of resistance to eutrophication. [ABSTRACT FROM AUTHOR]

Multi-indicator palaeoecological studies have become increasingly popular over the last decade as the need for a more complete understanding of lake ecological histories has increased. However, the true potential of the full biological record for assessing the potential drivers of observed ecological shifts in lake sediment records has rarely been demonstrated., Here, we examine the remains of a range of food-web components including algae (diatoms), macrophytes (plant macrofossils), zooplankton (chitinous and ephippial Cladocera remains), invertebrates (including chironomids, bryozoans, Mollusca) and fish (fish scales and fish leech egg cocoons) in multiple sediment cores from Groby Pool, an enriched English shallow lake, to assess whole-ecosystem response to eutrophication over the last two centuries. We focus on three striking changes in the palaeorecord, namely the post-1900 increase in Daphnia spp., the post-1840 decline in Cristatella mucedo and the post-1940 increase in Cocconeis placentula, and utilise the multi-indicator palaeoecological data to evaluate possible explanations for these patterns., Principal curves analysis revealed marked and broadly simultaneous changes in the plant macrofossils, cladocerans, diatoms and chironomids (as well as in other animal remains such as bryozoans and Mollusca), indicating an early period of enrichment most likely associated with land-use change in the late 18th century, followed by a more recent eutrophication phase coincident with the discharge of sewage effluent to the lake from 1935., Ecological change, resulting from eutrophication, was shown to have progressed slowly and steadily and to have occurred at all trophic levels with a shift from a relatively diverse 'mesotrophic' macrophyte assemblage, dominance by benthic diatoms and plant-associated Chydoridae and chironomids towards a relatively species-poor, 'eutrophic' macrophyte community with dominance by planktonic algae (e.g. Cyclostephanoid diatom taxa), planktonic Cladocera ( Bosmina, Daphnia) and a chironomid fauna dominated by mud-associated taxa. The inferred shift in the macrophyte community from charophyte to fine-leaved pondweed and Callitriche truncata suggests a reduction in the seasonal duration of plant dominance., The multi-indicator analysis indicates that a combination of increased phytoplankton biomass and low zooplanktivorous fish predation is likely to explain the recent increases in Daphnia spp., while loss of plant habitat and increased competition for food appear to be the most likely causes of the observed decline in C. mucedo, and resistance to increased grazing pressure from invertebrates is the most probable driver of the C. placentula increase., Our study illustrates the potential of using the full array of fossil groups preserved in lake sediment cores to infer ecosystem dynamics over centennial timescales and to contribute to our understanding of the mechanisms that may link biological assemblages to a range of forcing factors. Further, this paper provides methodological guidance by demonstrating the ability of amalgamated records from three cores to reveal a strong sequence of events and coherent patterns. [ABSTRACT FROM AUTHOR]

Eutrophication alters the trophic dynamics in lakes and may result in homogenisation of biotic communities. How nutrient enrichment drives patterns of homogenisation of fish species composition at within-lake (local) and among-lake (regional) scales is, however, not well studied., To test for homogenisation in fish communities, we analysed number, biomass and individual mean body mass of the different fish species present in 53 Danish lakes with contrasting depths, surface area and eutrophication., A combination of uni- and multivariate techniques revealed that eutrophication homogenises fish community composition in the littoral zone of both shallow and deep lakes at within- and among-lake scales, a notable contrast being that community composition was not homogenised in the offshore in deep lakes., In addition, fish species richness and diversity converged with progressive eutrophication and mean lake depth in all lake zones. For deep lakes, surface area was positively related to increasing differences in fish species richness and diversity., Increased homogeneity of this key assemblage may have profound implications for ecosystems and their stability (such as decreased resilience to disturbance, reduced biological complexity and increased vulnerability to large-scale and stochastic environmental events)., Thus, to fully understand the impacts of eutrophication on aquatic communities at both local and regional scales, the effects of nutrient enrichment on compositional heterogeneity should be considered. [ABSTRACT FROM AUTHOR]

Groups of organisms often have congruent patterns of diversity or community structure due to similar environmental requirements. However, ecological interactions across trophic levels may also promote congruence independent of environmental drivers through selective predation, niche partitioning, or facilitation. We examined congruence between phytoplankton and zooplankton communities using 20 years of monitoring data from 17 Danish lakes, most of which were subject to external nutrient loading reduction after a period of eutrophication. Linear mixed effect models and partial Mantel tests were used to elucidate the extent to which congruence in genus richness and composition was driven by environmental factors. Congruence not explained by environmental controls might indicate ecological interactions across trophic levels of lake plankton. Genus richness and composition of phyto- and zooplankton were significantly congruent. Environmental factors had limited power to explain the genus richness of phyto- and zooplankton (R²: 6% and 12%, respectively). Including richness of the reciprocal group among the predictors markedly improved each respective model and explanatory power (R²: 11% and 17%, respectively). Similarly, a large proportion of the congruence in genus composition was independent of environmental dissimilarity (Mantel r: 0.29 and partial Mantel r after accounting for environmental control: 0.17). The strength of the congruence varied among different groups of phyto- and zooplankton, likely reflecting that the different zooplankton groups differ in their grazing size spectra and thus in the strength of their coupling with the phytoplankton assemblages. Remarkably, congruence with phytoplankton was strongest for the smallest group of zooplankton, rotifers, which graze on a limited size spectrum of phytoplankton. Moreover, congruence was stronger in low-nutrient lakes, suggesting that the strength of the interactions between the two groups weakens with eutrophication. This is likely due to changes in trophic dynamics, where enhanced fish predation on large-bodied zooplankton with increasing nutrient levels results in reduced zooplankton grazing control of phytoplankton assemblages. [ABSTRACT FROM AUTHOR]

Climate warming in (sub)arctic regions is expected to increase freshwater fish overwinter survival and dispersal, potentially with strong implications for macroinvertebrate assemblage composition and ecosystem processes. Several studies worldwide have shown large effects of top predators (usually fish) on macroinvertebrates in streams. However, the influence of top predators on trophic diversity, the range of food resources exploited and trophic niche redundancy is less well studied, particularly in cold regions., Using stable isotopes (13C and 15N) and fish gut content analysis, we investigated the effect of top predators on macroinvertebrate food webs in streams in Greenland by comparing adjacent sites with and without fish ( Gasterosteus aculeatus)., Food-web metrics estimated from stable isotope data showed that the presence of fish reduced the diversity of food sources exploited by macroinvertebrates as well as their trophic diversity. In addition, fish presence increased packing and trophic redundancy of macroinvertebrate taxa in the food web, possibly due to behavioural changes in foraging activity. Furthermore, predatory macroinvertebrate taxa were unable to attain the trophic position of fish so that food webs were one trophic level longer in streams with fish. Focusing on macroinvertebrate food webs alone, predatory macroinvertebrates did not change their trophic position in the presence of fish., Filter feeders dominated the macroinvertebrate assemblage when fish were present, while the relative abundance of collector-gatherers was marginally higher in the fishless streams. This pattern was consistent with stronger selectivity for collector-gatherers by fish., Climate-driven fish colonisation in currently fishless Greenland streams may induce a shift in macroinvertebrate food webs, with a reduction in both trophic diversity and the variety of food sources consumed. To some extent, this might counteract a change towards a broader use of food resources by macroinvertebrates that might otherwise be expected at higher temperatures. In addition, a shift in the macroinvertebrate assemblage towards dominance of filter feeders can be expected to promote an increase in periphyton biomass in streams with fish. [ABSTRACT FROM AUTHOR]

Ponds have significant conservation value due to their potentially high contribution to local and regional diversity. However, most ponds are located in anthropogenically influenced areas, and their biodiversity is constantly threatened by human activities. Thus, knowledge of the effect of pond management on biodiversity is essential for designing effective conservation strategies., Here, we study the main drivers of diversity of three functional groups of primary producers (phytoplankton, filamentous green algae and submerged macrophytes) in 87 ponds distributed across a large region (c. 90000 km2) in Southern Spain. We hypothesised that spatial effects would increase with increasing propagule size. However, given the regional extent of the study, we anticipated that both spatial and environmental controls would be significant., We determined α -, β - and γ-components of biodiversity for each functional group and pond type (embankment ponds, excavated ponds and artificial ponds) and assessed the influence of environmental and spatial drivers on diversity with generalised additive models ( GAMs). Redundancy analyses ( RDAs) with variation partitioning were used to determine the relative contribution of environmental and spatial predictors of the community assembly. Spatial variables were calculated by applying distance-based Moran's eigenvector maps (db- MEM)., Both α - and β -diversities of phytoplankton and filamentous green algae varied significantly with pond type. Generally, environmental predictors of diversity were more important than spatial variables. Assemblage structure was controlled by water chemistry and eutrophication, with a marked influence of pond type. Spatial variables included broad-scale variation for the three groups of primary producers, which were also strongly influenced by the management regime., Limited management activities, as occurs at embankment ponds, promoted the local richness of phytoplankton and contributed importantly to the regional diversity of macrophytes. Moreover, the relative contribution of environmental and spatial variables was similar between embankment ponds and natural ecosystems, that is, dispersal limitation increasing with propagule size. Excavated and artificial ponds also contributed importantly to regional diversity by enhancing phytoplankton and filamentous green algal β-diversity. However, spatial patterns in the latter pond type did not meet our expectations, most likely due to the intensive disturbance from pond management hampering the development of macrophytes. [ABSTRACT FROM AUTHOR]

Aquatic macrophytes are commonly used to assess the ecological condition of lakes. Little is known, however, about long-term macrophyte dynamics in shallow lakes. In the absence of historical data, the remains of macrophytes (fruits, seeds and vegetative fragments) found in lake sediments may provide just such information. In order to interpret confidently past change in aquatic plant communities from their sedimentary remains, it is vital to establish the similarity between the contemporary and fossil assemblages., We investigated the relationship between present lake vegetation and plant macrophyte remains in surface sediments. Thirty-five shallow lakes, spanning around six degrees of latitude and mostly located in the semi-arid Mediterranean climatic zone of Turkey, were sampled for aquatic plants, surface sediment plant remains and a range of other key environmental variables., Around 50% of the taxa recorded in the modern vegetation were represented in the sediment. Sedimentary macrofossils of some taxa were under- or over-represented relative to their frequency in the modern vegetation, for example Potamogeton spp. and Characeae, respectively. Despite this disparity, there was good agreement between the assemblage composition of the modern and sedimentary samples. Furthermore, conductivity and trophic state (as indicated by total nitrogen, total phosphorus and chlorophyll- a) were the environmental variables most clearly correlated with both the contemporary and macrofossil assemblages in these lakes., We conclude that aquatic macrophyte macrofossils can be used as reliable indicators of ecological status and to determine qualitative changes in assemblages of aquatic plants consequent to environmental change (e.g. in lake trophic status and/or salinity). This may be especially useful for lakes in arid and semi-arid Mediterranean regions, which are particularly vulnerable to hydrological constraints under climate change. [ABSTRACT FROM AUTHOR]

ABSTRACT The principal aim of this study was to disentangle hydrochemical influences on primary producers in a pristine, flood-pulse ecosystem. This was undertaken by analysing diatoms from 100 sample points from hydrologically distinct regions in the Okavango Delta, Botswana. Cluster analysis was undertaken using two-way indicator species analysis (TWINSPAN), and groups used to classify sample points in a principal components analysis (PCA) biplot. Linear discriminant analysis (LDA) was performed using hydrological data and diatom guilds as explanatory variables. A series of ordinations using redundancy analysis (RDA) was undertaken to assess which variables significantly accounted for diatom variation across the Delta. Species-response curves for major taxa were generated using generalized additive models (GAMs). Cluster analysis revealed six distinct groups. Groups 5 and 6 consisted mainly of seasonally inundated floodplain sites, which lay at one end of a significant gradient revealed by PCA. Floodplain diatoms were characteristically N-heterotrophs, requiring elevated concentrations of key resources such as total nitrogen (TN) and SiO2. Using forward selection, constrained RDA reveals five variables were significant in explaining diatom distributions across the Delta: hydroperiod class, flood frequency, flow velocity and nutrients SiO2 and TN. Species-response curves show that motile diatoms were most abundant in seasonally inundated floodplains. Species diversity was significantly higher in the upper Panhandle region of the Delta, which may be related to moderate levels of disturbance and increased resource limitation. Species diversity was significantly lower during the period of maximum flood extent, which may in turn be related to fewer limiting resources. Copyright © 2011 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

1. Flood-pulsed wetlands make vital contributions to local and global biodiversity. However, the patterns and controls of spatial and temporal variation in aquatic biodiversity in flood-pulsed wetlands are not well understood. We analysed the relationship between variation in hydrological regime and the patterns of aquatic biodiversity in a large pristine flood-pulsed wetland, the Okavango Delta, Botswana. 2. Surveys of water chemistry, diatoms and macroinvertebrates were conducted over the seasonal phases of the flood pulse. Hydrological variables of flood frequency and hydroperiod class were collated from 16 years of satellite images. Multivariate regression trees and generalised least squares regression were used to determine the chief controls of community composition and taxon richness. 3. Hydroperiod class, phase of the flood and conductivity explained 32% and 43% of the variation in diatom and invertebrate taxon richness, respectively. There was a negative relationship between hydroperiod class and invertebrate taxon richness on the rising, peak and receding flood, whereas at low flood there was no significant relationship. Multivariate regression tree analysis revealed hydroperiod class, phase of the flood and conductivity as the dominant forces shaping invertebrate and diatom community composition. 4. Seasonal and spatial variation in hydrological conditions are the principal drivers of variation in aquatic biodiversity in flood-pulsed wetlands. In pristine flood-pulsed wetlands, increased productivity caused by the arrival of the flood waters appears to override disturbance and connectivity in shaping taxon richness and community composition. Thus, these data suggest that the maintenance of a rich mosaic of habitats covering a broad range of hydroperiod is the key to preserving aquatic biodiversity and natural ecosystem function in flood-pulsed wetlands. [ABSTRACT FROM AUTHOR]

ABSTRACT [ABSTRACT FROM AUTHOR]

The purpose of this study was to estimate the cost-effectiveness of using individual-donor nucleic acid testing (ID-NAT) in addition to serologic tests compared with the sole use of serologic tests for the identification of hepatitis B virus (HBV), hepatitis C virus (HCV), and human immunodeficiency virus (HIV) among blood donors in Sweden. The two strategies analyzed were serologic tests and ID-NAT plus serologic tests. A health-economic model was used to estimate the lifetime costs and effects. The effects were measured as infections avoided and quality-adjusted life-years (QALYs) gained. A societal perspective was used. The largest number of viral transmissions occurred with serologic testing only. However, the risks for viral transmissions were very low with both strategies. The total cost was mainly influenced by the cost of the test carried out. The cost of using ID-NAT plus serologic tests compared to serologic tests alone was estimated at Swedish Krona (SEK) 101 million (USD 12.7 million) per avoided viral transmission. The cost per QALY gained was SEK 22 million (USD 2.7 million). Using ID-NAT for testing against HBV, HCV, and HIV among blood donors leads to cost-effectiveness ratios that are far beyond what is usually considered cost-effective. The main reason for this is that with current methods, the risks for virus transmission are very low in Sweden. [ABSTRACT FROM AUTHOR]

1. Seasonal relationships between macrophyte and phytoplankton populations may alter considerably as lakes undergo eutrophication. Understanding of these changes may be key to the interpretation of ecological processes operating over longer (decadal-centennial) timescales. 2. We explore the seasonal dynamics of macrophytes (measured twice in June and August) and phytoplankton (measured monthly May–September) populations in 39 shallow lakes (29 in the U.K. and 10 in Denmark) covering broad gradients for nutrients and plant abundance. 3. Three site groups were identified based on macrophyte seasonality; 16 lakes where macrophyte abundance was perennially low and the water generally turbid (‘turbid lakes’); 7 where macrophyte abundance was high in June but low in August (‘crashing’ lakes); and 12 where macrophyte abundance was high in both June and August (‘stable’ lakes). The seasonal behaviour of the crashing and turbid lakes was extremely similar with a consistent increase in nutrient concentrations and chlorophyll- a over May–September. By contrast in the stable lakes, seasonal changes were dampened with chlorophyll- a consistently low (<10–15 μg L−1) over the entire summer. The crashing lakes were dominated by one or a combination of Potamogeton pusillus, Potamogeton pectinatus and Zannichellia palustris, whereas Ceratophyllum demersum and Chara spp. were more abundant in the stable lakes. 4. A long-term loss of macrophyte species diversity has occurred in many shallow lakes affected by eutrophication. One common pathway is from a species-rich plant community with charophytes to a species-poor community dominated by P. pusillus, P. pectinatus and Z. palustris. Such compositional changes may often be accompanied by a substantial reduction in the seasonal duration of plant dominance and a greater tendency for incursions by phytoplankton. We hypothesise a slow-enacting (10–100 s years) feedback loop in nutrient-enriched shallow lakes whereby increases in algal abundance are associated with losses of macrophyte species and hence different plant seasonal strategies. In turn such changes may favour increased phytoplankton production thus placing further pressure on remaining macrophytes. This study blurs the distinction between so-called turbid phytoplankton-dominated and clear plant-dominated shallow lakes and suggests that plant loss from them may be a gradual process. [ABSTRACT FROM AUTHOR]

1. Quantitative palaeolimnology has traditionally sought to quantify species-environment relationships to use alterations in biological assemblages to reflect past environmental change. Transfer functions have used regression techniques, such as weighted averaging, to define taxon optima and tolerance for a single chemical or biological variable. 2. Cladoceran assemblages and their sub-fossil remains in shallow lakes are shaped by a combination of interacting factors. Partial constrained ordination of sub-fossil cladoceran assemblages from 39 shallow lakes (29 in Norfolk, U.K. and 10 in Denmark) indicated that both zooplanktivorous fish (ZF) density and submerged macrophyte abundance significantly influenced community composition. These dual structuring forces precluded the use of a transfer function as one of the key assumptions of this approach was not met, namely that environmental variables apart from the variable being modelled have negligible influence on species distribution or that there is a linear relationship between the two. Separate transfer functions for ZF and macrophyte abundance were developed but had poor performance diagnostics with low bootstrapped r2, high root mean square error of prediction (RMSEP) and large bias. 3. To obviate the problem of multiple structuring forces a multivariate regression tree (MRT) was employed, which allows for more than one explanatory variable within a model. The MRT analysis defined six groups with discrete ranges of ZF and macrophyte densities. The technique identified critical values or ‘break points’ in ZF and macrophyte abundances which result in significant alterations in the sub-fossil cladoceran assemblage. In addition, the MRT groups had different summer mean values for chlorophyll-a, Secchi depth, total phosphorus and nitrate-nitrogen. 4. The predictive abilities of the model were assessed by comparing the observed versus predicted MRT group membership. In general group membership was reliably predicted, suggesting sub-fossil cladoceran assemblages reliably reflect ZF and macrophyte density in shallow lakes. For a relatively small number of sites there were differences between the observed and predicted MRT group membership. These failures of prediction may result, at least in part, from the disparity of the time period represented by the environmental data and the surface sediment cladoceran assemblage. [ABSTRACT FROM AUTHOR]

1. Palaeolimnology and contemporary ecology are complementary disciplines but are rarely combined. By reviewing the literature and using a case study, we show how linking the timescales of these approaches affords a powerful means of understanding ecological change in shallow lakes. 2. Recently, palaeolimnology has largely been pre-occupied with developing transfer functions which use surface sediment-lake environment datasets to reconstruct a single environmental variable. Such models ignore complex controls over biological structure and can be prone to considerable error in prediction. Furthermore, by reducing species assemblage data to a series of numbers, transfer functions neglect valuable ecological information on species’ seasonality, habitat structure and food web interactions. These elements can be readily extracted from palaeolimnological data with the interpretive assistance of contemporary experiments and surveys. For example, for one shallow lake, we show how it is possible to infer long-term seasonality change from plant macrofossil and fossil diatom data with the assistance of seasonal datasets on macrophyte and algal dynamics. 3. On the other hand, theories on shallow lake functioning have generally been developed from short-term (<1–15 years) studies as opposed to palaeo-data that cover the actual timescales (decades–centuries) of shallow lake response to stressors such as eutrophication and climate change. Palaeolimnological techniques can track long-term dynamics in lakes whilst smoothing out short-term variability and thus provide a unique and important means of not only developing ecological theories, but of testing them. 4. By combining contemporary ecology and palaeolimnology, it should be possible to gain a fuller understanding of changing ecological patterns and processes in shallow lakes on multiple timescales. [ABSTRACT FROM AUTHOR]

1. Eutrophication has a profound effect on the biological structure and function of shallow lakes, altering the composition and abundance of submerged macrophyte and fish assemblages. Relatively little is known, however, about decadal to centennial-scale change in these important aspects of shallow lake ecology. 2. Established palaeolimnological inference models are limited to reconstructing a single variable. As macrophyte and zooplanktivorous fish abundance exert dual and interacting controls on cladoceran assemblages a single variable inference model may contain significant error. To obviate this problem, we applied a new cladoceran-based multivariate regression tree (MRT) model to cladoceran subfossil assemblages from dated cores from a small shallow lake (Felbrigg Lake, U.K.) to assess long-term change in fish and submerged macrophyte abundance. Plant macrofossil, chironomid and mollusc subfossil assemblages were also analysed to track changes in biological structure and function and to evaluate the inferences of the MRT model. 3. Over the 200+ year period covered by the sediment cores, there was good agreement in the timing and nature of ecological change reflected by the plant macrofossil, mollusc, chironomid and cladoceran data. The sediment sequence was divided into three dated zones: c. 1797–1890, c. 1890–1954 and c. 1954–present. Prior to 1890 plant-associated mollusc, cladoceran and chironomid assemblages indicated a species-rich macrophyte community; a scenario confirmed by the plant macrofossil data. From c. 1890 to 1954 macrophyte-associated species of all three invertebrate groups remained abundant but the proportion of pelagic cladocerans rose. Post-1954 mollusc and chironomid assemblages changed to sediment associated detrital feeders and the proportion of pelagic cladoceran taxa increased further. 4. The cladoceran-based MRT model indicated a long period of stability, c. 1790–1927, characterised by abundant submerged macrophytes and zooplanktivorous fish. From c. 1927 to 1980, the MRT model inferred a decline in zooplanktivorous fish density (ZF) but relative stability in August macrophyte abundance. From 1980 to 2000, an increase in zooplanktivorous fish was inferred tallying well with available data on the fish population (since the 1970s), which indicated extirpation of perch in the 1970s and a subsequent increase in the rudd population. The model inferred little change in August macrophyte abundance until post- c. 1980 at which point it indicated a decline. The surface sediment assemblage was placed in MRT group A, where submerged plants are absent or very rare in late summer in good agreement with current conditions at the site. 5. The MRT model, applied here for the first time, appears to have successfully tracked changes in macrophyte abundance and ZF over the last 200 years at Felbrigg Lake. The inferences agreed with historical observations on the fish community and the supporting palaeolimnological data. Given that multiple structuring forces shape most biological communities, the application of a model capable of allowing for this represents a significant advance in palaeolimnology. [ABSTRACT FROM AUTHOR]

1. Shallow lakes are often cited as classic examples of systems that exhibit trophic cascades but, whilst they provide good model systems with which to test general ecological theory and to assess long-term community change, their food web linkages have rarely been resolved, so changes associated with the structure and dynamics of the ecological network as a whole are still poorly understood. 2. We sought to redress this, and to demonstrate the potential benefits of integrating palaeolimnological and contemporary data, by constructing highly resolved food webs and stable isotope derived measures of trophic interactions and niche space, for the extant communities of two shallow U.K. lakes from different positions along a gradient of eutrophication. The contemporary surface sediment cladoceran and submerged macrophyte assemblages in the less enriched site, Selbrigg Pond, matched the palaeolimnological assemblages of the more enriched site, Felbrigg Hall Lake, in its more pristine state during the 1920s. Thus, Selbrigg was a temporal analogue for Felbrigg, from which the consequences of long-term eutrophication on food web structure could be inferred. These data represent the first steps towards reconstructing not only past assemblages (i.e. nodes within a food web), but also past interactions (i.e. links within a food web): a significant departure from much of the previous research in palaeolimnology. 3. The more eutrophic food web had far fewer nodes and links, and thus a less reticulate network, than was the case for the more pristine system. In isotopic terms, there was vertical compression in δ15N range (NR) and subsequent increased overlap in isotopic niche space, indicating increased trophic redundancy within Felbrigg. This structural change, which was associated with a greater channelling of energy through a smaller number of nodes as alternative feeding pathways disappear, could lead to reduced dynamic stability, pushing the network towards further simplification. These changes reflected a general shift from a benthic-dominated towards a more pelagic system, as the plant-associated subweb eroded. 4. Although these data are among the first of their kind, the palaeo-analogue approach used here demonstrates the huge potential for applying food web theory to understand how and why these ecological networks change during eutrophication. Furthermore, because of the rich biological record preserved in their sediments, shallow lakes represent potentially important models for examining long-term intergenerational dynamics, thereby providing a means by which models and data can be integrated on meaningful timescales – a goal that has long proved elusive in food web ecology. [ABSTRACT FROM AUTHOR]

1. Submerged macrophyte and phytoplankton components of eutrophic, shallow lakes have frequently undergone dynamic changes in composition and abundance with important consequences for lake functioning and stability. However, because of a paucity of long-term survey data, we know little regarding the nature, direction and sequencing of such changes over decadal–centennial or longer timescales. 2. To circumvent this problem, we analysed multiple ( n = 5) chronologically correlated sediment cores for plant macro-remains and a single core for pollen and diatoms from one small, shallow, English lake (Felbrigg Hall Lake, Norfolk, U.K.), documenting 250 years of change to macrophyte and algal communities. 3. All five cores showed broadly similar stratigraphic changes in macrophyte remains with three distinct phases of macrophyte development: Myriophyllum–Chara–Potamogeton ( c. pre-1900), to Ceratophyllum–Chara–Potamogeton ( c. 1900–1960) and finally to Zannichellia–Potamogeton ( c. post-1960). Macrophyte species richness declined from at least 10 species pre-1900 to just four species at the present day. Additionally, in the final Zannichellia–Potamogeton phase, a directional shift between epi-benthic and phytoplankton-based primary production was indicated by the diatom data. 4. Based on macrophyte–seasonality relationships established for the region, concomitant with the final shift to Zannichellia–Potamogeton, we infer a reduction in the seasonal duration of plant dominance (plant-covered period). Furthermore, we hypothesise that this change in species composition resulted in a situation whereby macrophyte populations were seasonally ‘sandwiched’ between two phytoplankton peaks in spring and late summer as observed in the contemporary lake. 5. We suggest that eutrophication-induced reductions in macrophyte species richness, especially if the number of plant-seasonal strategies is reduced, may constrict the plant growing season. In turn, this may render a shallow lake increasingly vulnerable to seasonal invasions of phytoplankton resulting in further species losses in the plant community. Thus, as part of a slow (over perhaps 10–100s of years) and self-perpetuating process, macrophytes may be gradually pushed out by phytoplankton without the need for a perturbation as required in the alternative stable states model of plant loss. [ABSTRACT FROM AUTHOR]

1. To correctly interpret chironomid faunas for palaeoenvironmental reconstruction, it is essential that we improve our understanding of the relative influence of ecosystem variables, biotic as well as physicochemical, on chironomid larvae. To address this, we analysed the surface sediments from 39 shallow lakes (29 Norfolk, U.K., 10 Denmark) for chironomid head capsules, and 70 chironomid taxa (including Chaoborus) were identified. 2. The shallow lakes were selected over large environmental gradients of aquatic macrophytes, total phosphorus (TP) and fish communities. Redundancy analysis (RDA) identified two significant variables that explained chironomid distribution: macrophyte species richness ( P < 0.001) and TP ( P < 0.005). Generalised linear models (GLM) identified specific taxa that had significant relationships with both these variables. Macrophyte percentage volume infested (PVI) and species richness were significant in classifying the lake types based on chironomid communities undertwinspan analysis, although other factors, notably nutrient concentrations and fish communities, were also important, illustrating the complexities of classifying shallow lake ecosystems. Lakes with plant species richness >10 all had relatively diverse (Hill’s N2) chironomid assemblages, and lakes with Hill’s N2 >10 all had TP <250 μg L−1 and total fish densities <2 fish per m2. 3. Plant density (PVI), and perhaps more importantly species richness, were primary controls on the distribution of chironomid communities within these lakes. This clearly has implications for palaeoenvironmental reconstructions using zoobenthos remains (i.e. chironomids) and suggests that they could be used to track changes in benthic/pelagic production and could be used as indicators of changing macrophyte habitat. 4. Measuring key biological gradients, in addition to physicochemical gradients, allowed the major controls on chironomid distribution to be assessed more directly, in terms of plant substrate, food availability, competition and predation pressure, rather than implying indirect mechanisms through relationships with nutrients. Many of these variables, notably macrophyte abundance and species richness, are not routinely measured in such studies, despite their importance in determining zoobenthos in temperate shallow lakes. 5. When physical, chemical and ecological gradients are considered, as is often the case with palaeo-reconstructions rather than training sets chosen to maximise one gradient, complex relationships exist, and attempting to reconstruct a single trophic variable quantitatively may not be appropriate or reliable. [ABSTRACT FROM AUTHOR]

1. Sedimentary remains of aquatic plants, both vegetative (turions, leaves, spines) and reproductive (fruits, seeds, pollen), may provide a record of temporal changes in the submerged vegetation of lakes. An independent assessment of the degree to which these remains reflect past floristic change is, however, rarely possible. 2. By exploiting an extensive series of historical plant records for a small shallow lake we compare plant macrofossil (three cores) and pollen (one core) profiles with the documented sequence of submerged vegetation change since c. 1750 AD. The data set is based on 146 site visits with 658 observations including 42 taxa classified as aquatic, spanning 250 years. 3. Approximately 40% of the historically recorded aquatic taxa were represented by macro-remains. In general macrofossils underestimated past species diversity, with pondweeds (three of eight historically recorded Potamogeton species were found) particularly poorly represented. Nonetheless, several taxa not reported from historical surveys (e.g. Myriophyllum alterniflorum and Characeae) were present in the sediment record. 4. The pollen record revealed taxa which left no macro-remains (e.g. Littorella uniflora), and the macrofossil record provided improved taxonomic resolution for some taxa (e.g. Potamogeton) and a more reliable record of persistence, appearance and loss of others (e.g. Myriophyllum spp. and Nymphaeaceae). 5. Detrended correspondence analysis indicated that changes in the community composition evidenced by the palaeolimnological and historical records were synchronous and of a similar magnitude. Both records pointed to a major change at around 1800, with the historical record suggesting a more abrupt change than the sedimentary data. There was good agreement on a subsequent change c. 1930. 6. The palaeolimnological data did not provide a complete inventory of historically recorded species. Nevertheless, these results suggest that combined macrofossil and pollen records provide a reliable indication of temporal change in the dominant components of the submerged and floating-leaved aquatic vegetation of shallow lakes. As such palaeolimnology may provide a useful tool for establishing community dynamics and successions of plants over decadal to centennial timescales. [ABSTRACT FROM AUTHOR]

The continued chemotherapeutic application of cisplatin ( cis-diamminedichloroplatinum [II]) necessitates reduction of its doselimiting toxicity without decreasing its tumoricidal effect. This research project evaluated the efficacy of fosfomycin, a phosphonic acid antibiotic, in decreasing or ameliorating the ototoxicity (high frequency sensorineural hearing loss) and nephrotoxicity (renal tubular necrosis and interstitial nephritis) of cisplatin. Experimentally, fosfomycin effectively inhibits aminoglycoside-induced ototoxicity and nephrotoxicity in animals and humans. The efficacy of fosfomycin in blocking platinum-induced toxicity in the guinea pig was evaluated histologically and functionally using cytocochleography and light microscopy of the organ of Corti and the auditory brain stem evoked response (ABR), and light microscopy of renal corticomedullary tissues, small bowel, liver, lung, and peripheral nerve. The results demonstrate that fosfomycin ameliorates the acute renal tubular necrosis and interstitial nephritis and markedly inhibits the elevation of ABR thresholds and simultaneous outer hair cell loss that can result from cisplatinum administration. Fosfomycin should be considered apotential antidote for the dose-limiting ototoxicity and nephrotoxicity of cisplatin chemotherapy. [ABSTRACT FROM AUTHOR]

Eutrophication is commonly implicated in the reduction in macrophyte species richness in shallow lakes. However, the extent to which other more nuanced measures of macrophyte diversity, such as assemblage heterogeneity, are impacted concurrently by eutrophication over space and time and the joint influences of other factors (e.g., species invasions and connectivity) remains relatively poorly documented. Using a combination of contemporary and paleoecological data, we examine how eutrophication influences macrophyte assemblage heterogeneity and how nutrient enrichment interacts with watercourse connectivity, lake surface area, and relative zebra mussel abundance over space (within and among lakes) and time (decades to centuries) at the landscape scale. The study system is the Upper Lough Erne, Northern Ireland, UK, which is composed of a large main lake and several smaller satellite lakes that vary in their hydrological connectivity to the main lake. By applying homogeneity analysis of multivariate dispersions and partial redundancy analysis, we demonstrate that contemporary lake macrophyte heterogeneity and species richness are reduced in lakes with intensified eutrophication but are increased in lakes with greater zebra mussel abundance and lake surface area. Watercourse connectivity positively influenced assemblage heterogeneity and explained larger proportions of the variation in assemblage heterogeneity than local environmental factors, whereas variation in species richness was better related to local abiotic factors. Macrophyte fossil data revealed within‐ and among‐lake assemblage homogenization post‐1960, with the main lake and connected sites showing the highest rates of homogenization due to progressive eutrophication. The long‐term and contemporary data collectively indicate that eutrophication reduces assemblage heterogeneity over time by overriding the importance of regional processes (e.g., connectivity) and exerts stronger pressure on isolated lakes. Our results suggest further that in connected lake systems, assemblage heterogeneity may be impacted more rapidly by eutrophication than species richness. This means that early effects of eutrophication in many systems may be underestimated by monitoring that focuses solely on species richness and is not performed at adequate landscape scales. [ABSTRACT FROM AUTHOR]