Early Mortality, Cardiovascular, and Renal Diseases in Women's Lives Following Hypertensive Disorders of Pregnancy: The Prospective Nationwide Study CONCEPTION.

BACKGROUND: We aimed to evaluate the impact of hypertensive disorders of pregnancy occurrence, recurrence, onset time, and severity on mortality and on a wide range of cardiovascular outcomes in France. METHODS AND RESULTS: CONCEPTION (Cohort of Cardiovascular Diseases in Pregnancy) is a French nationwide prospective cohort using data from the National Health Data System. We included all women in CONCEPTION with no history of a cardiovascular event who delivered in France for the first time between 2010 and 2018 (N=2 819 655). Hypertensive disorders of pregnancy and cardiovascular outcomes during the study follow-up were identified using algorithms combining International Classification of Diseases, Tenth Revision (ICD-10) coded diagnoses during hospitalization and purchases of medication between 2010 and 2021. We fitted Cox models with time-varying exposure to assess the associations of hypertensive disorders of pregnancy with mortality and cardiovascular events. Women with gestational hypertension had a 1.25- to 2-fold higher risk of stroke, acute coronary syndrome, peripheral arterial disease, pulmonary embolism, and chronic kidney disease, and a 2- to 4-fold higher risk of rhythm and conduction disorder and heart failure. Women with preeclampsia had a 1.35- to 2-fold higher risk of rhythm or conduction disorder and pulmonary embolism during follow-up; a 2- to 4-fold higher risk of stroke, acute coronary syndrome, and peripheral arterial disease; and a 7- to 9-fold higher risk of heart failure and chronic kidney disease. They were 1.8 times more likely to die and 4.4 times more likely to die of cardiovascular causes. CONCLUSIONS: Hypertensive disorders of pregnancy drastically increase the risk of mortality, cardiovascular, and renal events early after pregnancy. Recurrent, severe, and early-onset preeclampsia further increases this risk.

Hemorrhagic Strokes Attributable to Chronic Alcohol Consumption and Heavy Episodic Drinking in France.

OBJECTIVES: To estimate the number of cases and deaths related to hemorrhagic stroke (HS) attributable to a chronic alcohol consumption and to heavy episodic drinking (HED) in France. METHODS: A population-attributable fraction (PAF) estimation approach was used. Relative risks for HS with alcohol consumption were extracted from the INTERSTROKE study. Levels of alcohol consumption in the French population were collected from the 2017 Health Barometer. Data on HS morbidity and mortality were extracted from the French National Health Data System (SNDS). RESULTS: We estimated that 7.2% (n = 2,100) and 6.6% (n = 1,900) of cases with HS were attributable to chronic alcohol consumption and HED, respectively. PAFs were higher in men than in women with 11.5% vs 2.6% for a chronic consumption and 10.7% vs 2.1% for HED, respectively. We estimated that 7.0% of HS deaths (n = 1,100) were attributable to chronic alcohol consumption and 5.1% attributable to HED (n = 800). Finally, 16.3% of patients with HS (n = 4,700) and 14.1% of HS deaths (n = 2,300) were attributable to overall chronic alcohol consumption or to monthly HED. DISCUSSION: These results remind the importance of alcohol consumption in the occurrence of HS and the importance of implementing primary and secondary prevention measures, particularly among young people, where HED is most common.

Complexities of cerebral small vessel disease, blood pressure, and dementia relationship: new insights from genetics.

Importance: There is increasing recognition that vascular disease, which can be treated, is a key contributor to dementia risk. However, the contribution of specific markers of vascular disease is unclear and, as a consequence, optimal prevention strategies remain unclear. Objective: To disentangle the causal relation of several key vascular traits to dementia risk: (i) white matter hyperintensity (WMH) burden, a highly prevalent imaging marker of covert cerebral small vessel disease (cSVD); (ii) clinical stroke; and (iii) blood pressure (BP), the leading risk factor for cSVD and stroke, for which efficient therapies exist. To account for potential epidemiological biases inherent to late-onset conditions like dementia. Design Setting and Participants: This study first explored the association of genetically determined WMH, BP levels and stroke risk with AD using summary-level data from large genome-wide association studies (GWASs) in a two-sample Mendelian randomization (MR) framework. Second, leveraging individual-level data from large longitudinal population-based cohorts and biobanks with prospective dementia surveillance, the association of weighted genetic risk scores (wGRSs) for WMH, BP, and stroke with incident all-cause-dementia was explored using Cox-proportional hazard and multi-state models. The data analysis was performed from July 26, 2020, through July 24, 2022. Exposures: Genetically determined levels of WMH volume and BP (systolic, diastolic and pulse blood pressures) and genetic liability to stroke. Main outcomes and measures: The summary-level MR analyses focused on the outcomes from GWAS of clinically diagnosed AD (n-cases=21,982) and GWAS additionally including self-reported parental history of dementia as a proxy for AD diagnosis (ADmeta, n-cases=53,042). For the longitudinal analyses, individual-level data of 157,698 participants with 10,699 incident all-cause-dementia were studied, exploring AD, vascular or mixed dementia in secondary analyses. Results: In the two-sample MR analyses, WMH showed strong evidence for a causal association with increased risk of ADmeta (OR, 1.16; 95%CI:1.05-1.28; P=.003) and AD (OR, 1.28; 95%CI:1.07-1.53; P=.008), after accounting for genetically determined pulse pressure for the latter. Genetically predicted BP traits showed evidence for a protective association with both clinically defined AD and ADmeta, with evidence for confounding by shared genetic instruments. In longitudinal analyses the wGRSs for WMH, but not BP or stroke, showed suggestive association with incident all-cause-dementia (HR, 1.02; 95%CI:1.00-1.04; P=.06). BP and stroke wGRSs were strongly associated with mortality but there was no evidence for selective survival bias during follow-up. In secondary analyses, polygenic scores with more liberal instrument definition showed association of both WMH and stroke with all-cause-dementia, AD, and vascular or mixed dementia; associations of stroke, but not WMH, with dementia outcomes were markedly attenuated after adjusting for interim stroke. Conclusion: These findings provide converging evidence that WMH is a leading vascular contributor to dementia risk, which may better capture the brain damage caused by BP (and other etiologies) than BP itself and should be targeted in priority for dementia prevention in the population.

Dimethylpolysulfides production as the major mechanism behind wheat fungal pathogen biocontrol, by Arthrobacter and Microbacterium actinomycetes.

IMPORTANCE: As the management of wheat fungal diseases becomes increasingly challenging, the use of bacterial agents with biocontrol potential against the two major wheat phytopathogens, Fusarium graminearum and Zymoseptoria tritici, may prove to be an interesting alternative to conventional pest management. Here, we have shown that dimethylpolysulfide volatiles are ubiquitously and predominantly produced by wheat-associated Microbacterium and Arthrobacter actinomycetes, displaying antifungal activity against both pathogens. By limiting pathogen growth and DON virulence factor production, the use of such DMPS-producing strains as soil biocontrol inoculants could limit the supply of pathogen inocula in soil and plant residues, providing an attractive alternative to dimethyldisulfide fumigant, which has many non-targeted toxicities. Notably, this study demonstrates the importance of bacterial volatile organic compound uptake by inhibited F. graminearum, providing new insights for the study of volatiles-mediated toxicity mechanisms within bacteria-fungus signaling crosstalk.

Impact of interventions scenarios targeting three main vascular risk factors on the future burden of dementia in France.

The epidemiological and societal burden of dementia is expected to increase in the coming decades due to the world population aging. In this context, the evaluation of the potential impact of intervention scenarios aiming at reducing the prevalence of dementia risk factors is an active area of research. However, such studies must account for the associated changes in mortality and the dependence between the risk factors. Using micro-simulations, this study aims to estimate the changes in dementia burden in France in 2040 according to intervention scenarios targeting the prevention or treatment of hypertension, diabetes and physical inactivity. Accounting for their communality and their effects on mortality, the results show that the disappearance of hypertension, diabetes and physical inactivity in France in 2020 could decrease dementia prevalence by 33% among men and 26% among women in 2040 and increase the life expectancy without dementia at age 65 by 3.4 years (men) and 2.6 years (women). Among the three factors, the prevention of hypertension would be the most efficient. These projections rely on current estimates of the risk of dementia and death associated with risk factors. Thanks to the R package developed they could be refined for different countries or different interventions and updated with new estimates.

Estimating the Future Burden of Myocardial Infarction in France Until 2035: An Illness-Death Model-Based Approach.

Purpose: In France, myocardial infarction (MI) was the second leading cause of years of life lost in 2019. Estimating the burden of MI in future years could help policymakers and other actors anticipate care and prevention needs and guide them in public health decision-making. Materials and Methods: Using data from the French hospital discharge database from 2007 to 2015 (n = 519,400), demographic data, and an illness-death model, we projected incidence, prevalence, number of prevalent cases and mean age of incident MI cases in France. The methodology took into account the age-cohort effect on MI incidence, mortality of healthy and diseased subjects, and the time since disease onset. Results: Projections highlighted an increase in MI prevalence in men between 2015 and 2035 from 2.52% (95% uncertainty interval (UI): [2.48-2.56]) in 2015 to 4.02% ([3.92-4.12]) in 2035, and from 0.85% ([0.83-0.87]) to 1.44% ([1.38-1.50]) in women. This corresponds to an increase of 365,000 cases between 2015 and 2035 (+81.1%) for men and 146,000 cases for women (+88.0%). The difference in the mean age of incident cases between men and women decreased from 9.52 in 2015 to 5.49 years in 2035. Conclusion: Our projections forecast an increase in MI prevalence between 2015 and 2035 in men and women, especially in relatively younger women. Using statistical models such as ours can help assess the impact of prevention campaigns for the main cardiovascular disease risk factors on the future MI prevalence.

Antiherpetic drugs: a potential way to prevent Alzheimer's disease?

BACKGROUND: Considering the growing body of evidence suggesting a potential implication of herpesviruses in the development of dementia, several authors have questioned a protective effect of antiherpetic drugs (AHDs) which may represent a new means of prevention, well tolerated and easily accessible. Subsequently, several epidemiological studies have shown a reduction in the risk of dementia in subjects treated with AHDs, but the biological plausibility of this association and the impact of potential methodological biases need to be discussed in more depth. METHODS: Using a French medico-administrative database, we assessed the association between the intake of systemic AHDs and the incidence of (i) dementia, (ii) Alzheimer's disease (AD), and (iii) vascular dementia in 68,291 subjects over 65 who were followed between 2009 and 2017. Regarding potential methodological biases, Cox models were adjusted for numerous potential confounding factors (including proxies of sociodemographic status, comorbidities, and use of healthcare) and sensitivity analyses were performed in an attempt to limit the risk of indication and reverse causality biases. RESULTS: 9.7% of subjects (n=6642) had at least one intake of systemic AHD, and 8883 incident cases of dementia were identified. Intake of at least one systemic AHD during follow-up was significantly associated with a decreased risk of AD (aHR 0.85 95% confidence interval [0.75-0.96], p=0.009) and, to a lesser extent with respect to p values, to both dementia from any cause and vascular dementia. The association with AD remained significant in sensitivity analyses. The number of subjects with a regular intake was low and prevented us from studying its association with dementia. CONCLUSIONS: Taking at least one systemic AHD during follow-up was significantly associated with a 15% reduced risk of developing AD, even after taking into account several potential methodological biases. Nevertheless, the low frequency of subjects with a regular intake questions the biological plausibility of this association and highlights the limits of epidemiological data to evaluate a potential protective effect of a regular treatment by systemic AHDs on the incidence of dementia.

Sex-related differences in aging rate are associated with sex chromosome system in amphibians.

Sex-related differences in mortality are widespread in the animal kingdom. Although studies have shown that sex determination systems might drive lifespan evolution, sex chromosome influence on aging rates have not been investigated so far, likely due to an apparent lack of demographic data from clades including both XY (with heterogametic males) and ZW (heterogametic females) systems. Taking advantage of a unique collection of capture-recapture datasets in amphibians, a vertebrate group where XY and ZW systems have repeatedly evolved over the past 200 million years, we examined whether sex heterogamy can predict sex differences in aging rates and lifespans. We showed that the strength and direction of sex differences in aging rates (and not lifespan) differ between XY and ZW systems. Sex-specific variation in aging rates was moderate within each system, but aging rates tended to be consistently higher in the heterogametic sex. This led to small but detectable effects of sex chromosome system on sex differences in aging rates in our models. Although preliminary, our results suggest that exposed recessive deleterious mutations on the X/Z chromosome (the "unguarded X/Z effect") or repeat-rich Y/W chromosome (the "toxic Y/W effect") could accelerate aging in the heterogametic sex in some vertebrate clades.

From Strain Characterization to Field Authorization: Highlights on Bacillus velezensis Strain B25 Beneficial Properties for Plants and Its Activities on Phytopathogenic Fungi.

Agriculture is in need of alternative products to conventional phytopharmaceutical treatments from chemical industry. One solution is the use of natural microorganisms with beneficial properties to ensure crop yields and plant health. In the present study, we focused our analyses on a bacterium referred as strain B25 and belonging to the species Bacillus velezensis (synonym B. amyloliquefaciens subsp. plantarum or B. methylotrophicus), a promising plant growth promoting rhizobacterium (PGPR) and an inhibitor of pathogenic fungi inducing crops diseases. B25 strain activities were investigated. Its genes are well preserved, with their majority being common with other Bacillus spp. strains and responsible for the biosynthesis of secondary metabolites known to be involved in biocontrol and plant growth-promoting activities. No antibiotic resistance genes were found in the B25 strain plasmid. In vitro and in planta tests were conducted to confirm these PGPR and biocontrol properties, showing its efficiency against 13 different pathogenic fungi through antibiosis mechanism. B25 strain also showed good capacities to quickly colonize its environment, to solubilize phosphorus and to produce siderophores and little amounts of auxin-type phytohormones (around 13,051 µg/mL after 32 h). All these findings combined to the fact that B25 demonstrated good properties for industrialization of the production and an environmental-friendly profile, led to its commercialization under market authorization since 2018 in several biostimulant preparations and opened its potential use as a biocontrol agent.

Analysis of time-to-event for observational studies: Guidance to the use of intensity models.

This paper provides guidance for researchers with some mathematical background on the conduct of time-to-event analysis in observational studies based on intensity (hazard) models. Discussions of basic concepts like time axis, event definition and censoring are given. Hazard models are introduced, with special emphasis on the Cox proportional hazards regression model. We provide check lists that may be useful both when fitting the model and assessing its goodness of fit and when interpreting the results. Special attention is paid to how to avoid problems with immortal time bias by introducing time-dependent covariates. We discuss prediction based on hazard models and difficulties when attempting to draw proper causal conclusions from such models. Finally, we present a series of examples where the methods and check lists are exemplified. Computational details and implementation using the freely available R software are documented in Supplementary Material. The paper was prepared as part of the STRATOS initiative.

Patterns of Benzodiazepine Use and Excess Risk of All-Cause Mortality in the Elderly: A Nationwide Cohort Study.

INTRODUCTION: Despite the risks associated with their use, benzodiazepines remain used more widely than wisely. In this context, a better understanding of how their patterns of use can be associated with an increased risk of death appears essential. Indeed, the studies that investigated this association so far are inconsistent and question the influence of potential biases. OBJECTIVE: The objective of this study was to investigate the association of various patterns of benzodiazepine use with all-cause mortality. METHODS: A nationwide cohort of non-prevalent benzodiazepine users aged ≥ 65 years was identified using French healthcare insurance system claims databases. Exposure to benzodiazepines considered short-term, chronic (defined as a cumulated ≥ 6-month period over the previous 12 months), ongoing, and discontinued use. Using a Cox model, adjusted hazard ratios for all-cause mortality were estimated according to benzodiazepine patterns of use; exposure and confounders were treated as time-dependent variables. RESULTS: In the cohort of 54,958 individuals aged ≥ 65 years, adjusted hazard ratios for all-cause mortality and benzodiazepines were 2.26 (95% confidence interval 1.96-2.61) for short-term use, 3.86 (3.04-4.90) for chronic use-discontinued, and 3.05 (2.17-4.29) for chronic use-ongoing. At age 80 years, these were 1.62 (1.48-1.79), 2.00 (1.82-2.19) and 1.13 (1.02-1.26), respectively. Adjusted hazard ratios show similar decreases with age for all patterns of benzodiazepine use. CONCLUSIONS: These findings confirm the existence of an excess risk of mortality associated with benzodiazepine use and provide pattern- and age-specific estimates. Higher risks were observed for patients aged < 80 years, short-term use, or chronic use recently interrupted. If the two latter can relate to an indication bias, the associations found for ongoing chronic use and short-term use conversely support a potential causal hypothesis.

Impact of benzodiazepine consumption reduction on future burden of dementia.

Dementia is a major public health issue worldwide and chronic use of benzodiazepine, which is very frequent in northern countries, was found to be a risk factor of dementia. This work aims at evaluating the impact of a reduction in chronic use of benzodiazepine on the future burden of dementia in France. Using estimations of dementia incidence and of benzodiazepine use and nation-wide projections of mortality and population sizes, a Monte Carlo approach based on an illness-death model provided projections of several indicators of dementia burden. With no change in benzodiazepine consumption, the prevalence of dementia between age 65 and 99 in France in 2040 was estimated at 2.16 millions (95% confidence interval (CI) 1.93-2.38), with a life expectancy without dementia at 65 years equal to 25.0 years (24.7-25.3) for women and 23.8 years (23.5-24.2) for men. Assuming a disappearance of chronic use of benzodiazepine in 2020, the prevalence would be reduced by about 6.6% in 2040 and the life expectancy without dementia would increase by 0.99 (0.93-1.06) year among women and 0.56 (0.50-0.62) among men. To conclude, a modest but significant reduction in future dementia burden could be obtained by applying current recommendation for duration of benzodiazepine use.

Excess cumulative incidence estimation for matched cohort survival studies.

We suggest a regression approach to estimate the excess cumulative incidence function (CIF) when matched data are available. In a competing risk setting, we define the excess risk as the difference between the CIF in the exposed group and the background CIF observed in the unexposed group. We show that the excess risk can be estimated through an extended binomial regression model that actively uses the matched structure of the data, avoiding further estimation of both the exposed and the unexposed CIFs. The method naturally deals with two time scales, age and time since exposure and simplifies how to deal with the left truncation on the age time-scale. The model makes it easy to predict individual excess risk scenarios and allows for a direct interpretation of the covariate effects on the cumulative incidence scale. After introducing the model and some theory to justify the approach, we show via simulations that our model works well in practice. We conclude by applying the excess risk model to data from the ALiCCS study to investigate the excess risk of late events in childhood cancer survivors.

Drivers of amphibian population dynamics and asynchrony at local and regional scales.

Identifying the drivers of population fluctuations in spatially distinct populations remains a significant challenge for ecologists. Whereas regional climatic factors may generate population synchrony (i.e. the Moran effect), local factors including the level of density dependence may reduce the level of synchrony. Although divergences in the scaling of population synchrony and spatial environmental variation have been observed, the regulatory factors that underlie such mismatches are poorly understood. Few previous studies have investigated how density-dependent processes and population-specific responses to weather variation influence spatial synchrony at both local and regional scales. We addressed this issue in a pond-breeding amphibian, the great crested newt Triturus cristatus. We used capture-recapture data collected through long-term surveys in five T. cristatus populations in Western Europe. In all populations-and subpopulations within metapopulations-population size, annual survival and recruitment fluctuated over time. Likewise, there was considerable variation in these demographic rates between populations and within metapopulations. These fluctuations and variations appear to be context-dependent and more related to site-specific characteristics than local or regional climatic drivers. We found a low level of demographic synchrony at both local and regional levels. Weather has weak and spatially variable effects on survival, recruitment and population growth rate. In contrast, density dependence was a common phenomenon (at least for population growth) in almost all populations and subpopulations. Our findings support the idea that the Moran effect is low in species where the population dynamics more closely depends on local factors (e.g. population density and habitat characteristics) than on large-scale environmental fluctuation (e.g. regional climatic variation). Such responses may have far-reaching consequences for the long-term viability of spatially structured populations and their ability to respond to large-scale climatic anomalies.

Regression analysis in an illness-death model with interval-censored data: A pseudo-value approach.

Pseudo-values provide a method to perform regression analysis for complex quantities with right-censored data. A further complication, interval-censored data, appears when events such as dementia are studied in an epidemiological cohort. We propose an extension of the pseudo-value approach for interval-censored data based on a semi-parametric estimator computed using penalised likelihood and splines. This estimator takes interval-censoring and competing risks into account in an illness-death model. We apply the pseudo-value approach to three mean value parameters of interest in studies of dementia: the probability of staying alive and non-demented, the restricted mean survival time without dementia and the absolute risk of dementia. Simulation studies are conducted to examine properties of pseudo-values based on this semi-parametric estimator. The method is applied to the French cohort PAQUID, which included more than 3,000 non-demented subjects, followed for dementia for more than 25 years.

Does in vitro selection of biocontrol agents guarantee success in planta? A study case of wheat protection against Fusarium seedling blight by soil bacteria.

Biological control is a great hope for reducing the overutilization of pesticides in agricultural soils. It often involves microorganisms or molecules produced by microorganisms that will be able to interact with either a plant or pathogens of this plant to reduce the growth of the pathogen and limit its negative impact on the host plant. When new biocontrol products are developed, strains were mostly selected based on their ability to inhibit a pathogen of interest under in vitro conditions via antagonistic effects. Strains with no in vitro effect are often discarded and not tested in planta. But is the in vitro selection of bacterial agents according to their antagonism activities towards a plant pathogen the best way to get effective biocontrol products? To answer this question, we used wheat and the fungal pathogen Fusarium graminearum as a study pathosystem model. A library of 205 soil bacteria was screened in 2 types of in vitro growth inhibition tests against F. graminearum, and in an in planta experiment. We find strains which do not have inhibition phenotypes in vitro but good efficacy in planta. Interestingly, some strains belong to species (Microbacterium, Arthrobacter, Variovorax) that are not known in the literature for their ability to protect plants against fungal pathogens. Thus, developing a biocontrol product against F. graminearum must be preferentially based on the direct screening of strains for their protective activity on wheat plants against fungal diseases, rather than on their in vitro antagonistic effects on fungal growth.

Secular trends of mortality and dementia-free life expectancy over a 10-year period in France.

The aim of this paper was to investigate the evolution of mortality and life expectancy according to dementia in two French populations 10 years apart. Two different populations of subjects aged 65 or older included in PAQUID from 1988 to 1989 (n = 1342) and 3C from 1999 to 2000 (n = 1996) and initially not demented were followed over 10 years. Dementia was assessed using an algorithmic approach, and participants were considered to have dementia if they had an MMSE score < 24 AND a 4IADL score > 1. Illness-death models were used to compare mortality with and without dementia and to provide total life expectancy (LE), dementia-free life expectancy (DemFreeLE), life expectancy with dementia (DemLE), and survival with dementia. Mortality without dementia has decreased between the two populations among men [HR = 0.63 (0.49-0.81)] and women [HR = 0.67 (0.50-0.90)], whereas mortality with dementia has decreased for women only [HR = 0.59 (0.41-0.87)]. Total LE and DemFreeLE have increased between the 1990s and the 2000s populations (total LE: + 2.5 years; DemFreeLE: + 2.2 years); DemLE only slightly increased between the populations (DemLE: + 0.3 years). For survival with dementia, an increase in survival has been evidenced (mean survival: + 1.3 years) for women only. The improvement in DemFreeLE is promising. However, as the duration of life with dementia tends to increase for women, efforts to delay the onset of dementia should be reinforced.

Multiple density-dependent processes shape the dynamics of a spatially structured amphibian population.

Understanding the mechanisms that regulate the dynamics of spatially structured populations (SSP) is a critical challenge for ecologists and conservation managers. Internal population processes such as births and deaths occur at a local level, while external processes such as dispersal take place at an inter-population level. At both levels, density dependence is expected to play a critical role. At a patch scale, demographic traits (e.g., survival, breeding success) and the population growth rate can be influenced by density either negatively (e.g., competition effect) or positively (e.g., Allee effects). At the scale of an SSP, although positive density-dependent dispersal has been widely reported, an increasing number of studies have highlighted negative density-dependent dispersal. While many studies have investigated the effects of density on population growth or on dispersal, few have simultaneously examined density-dependent effects at the scale of both the local population and the entire SSP. In this study, we examine how density is related to demographic processes at both the pond level (survival and population growth) and the SSP level (between-pond dispersal) in a pond-breeding amphibian, the great crested newt (Triturus cristatus). The study was based on 20 years of individual capture-recapture (CR) data (from 1996 to 2015) gathered from an SSP made up of 12 experimental ponds ("patches"). We first used a CR multievent model to estimate both survival and dispersal rates in specific ponds as a function of distance between ponds. Then, using a second CR multievent model, we examined whether survival and recapture rates were influenced by population density in a pond. Lastly, we used state-space time series models to investigate whether density affected population growth in each pond. Our results found a positive density-dependent effect on survival and a negative density-dependent effect on departure. In addition, the findings indicate that population growth was negatively related to density in all 12 ponds. These results support the hypothesis that in SSPs, density may have multiple and contrasting effects on demographic parameters and growth rates within local populations as well as on dispersal. This study underlines the need to better understand how density dependence may influence potential trade-offs between life-history strategies and life-history stages.

Context-dependent dispersal, public information, and heterospecific attraction in newts.

Dispersal is one of the main processes that determine community structure. Individuals make dispersal decisions according to environmental and/or social cues that reflect the fitness prospects in a given patch. The presence and abundance of heterospecifics within the same ecological guild, and/or their breeding success, may act as public information that influences movement decisions. To date, most studies investigating the role of heterospecific attraction have focused on habitat choice, using both experimental and correlational approaches. The present study is the first to examine how long-term variation in heterospecific density in breeding patches may affect dispersal patterns in spatially structured populations. We investigate how the dispersal decisions of the great crested newt (Triturus cristatus) are related to the variable density of two other newt species, the alpine newt (Ichthyosaura alpestris) and the palmate newt (Lissotriton helveticus). To examine this issue, we used capture-recapture data collected in an experimental pond network over a 20-year period. The results revealed that the great crested newt's dispersal is context dependent and is affected by variation in heterospecific density: individuals were less likely to emigrate from ponds with high heterospecific density and were more likely to immigrate to ponds with high heterospecific density. These findings suggest that individuals adjust their dispersal decisions at least partly based on public information provided by heterospecifics. This mechanism may play a critical role in the dynamics of spatially structured populations and community functioning.