AbstractThe fitness of immigrants and their descendants produced within recipient populations fundamentally underpins the genetic and population dynamic consequences of immigration. Immigrants can in principle induce contrasting genetic effects on fitness across generations, reflecting multifaceted additive, dominance, and epistatic effects. Yet full multigenerational and sex-specific fitness effects of regular immigration have not been quantified within naturally structured systems, precluding inference on underlying genetic architectures and population outcomes. We used four decades of song sparrow (Melospiza melodia) life history and pedigree data to quantify fitness of natural immigrants, natives, and their F1, F2, and backcross descendants and test for evidence of nonadditive genetic effects. Values of key fitness components (including adult lifetime reproductive success and zygote survival) of F1 offspring of immigrant-native matings substantially exceeded their parent mean, indicating strong heterosis. Meanwhile, F2 offspring of F1-F1 matings had notably low values, indicating surprisingly strong epistatic breakdown. Furthermore, magnitudes of effects varied among fitness components and differed between female and male descendants. These results demonstrate that strong nonadditive genetic effects on fitness can arise within weakly structured and fragmented populations experiencing frequent natural immigration. Such effects will substantially affect the net degree of effective gene flow and resulting local genetic introgression and adaptation.
Animals, Wild , Hybrid Vigor , Animals , Female , Male , Birds , Emigration and Immigration
Impacts of immigration on micro-evolution and population dynamics fundamentally depend on net rates and forms of resulting gene flow into recipient populations. Yet, the degrees to which observed rates and sex ratios of physical immigration translate into multi-generational genetic legacies have not been explicitly quantified in natural meta-populations, precluding inference on how movements translate into effective gene flow and eco-evolutionary outcomes. Our analyses of three decades of complete song sparrow (Melospiza melodia) pedigree data show that multi-generational genetic contributions from regular natural immigrants substantially exceeded those from contemporary natives, consistent with heterosis-enhanced introgression. However, while contributions from female immigrants exceeded those from female natives by up to three-fold, male immigrants' lineages typically went locally extinct soon after arriving. Both the overall magnitude, and the degree of female bias, of effective gene flow therefore greatly exceeded those which would be inferred from observed physical arrivals, altering multiple eco-evolutionary implications of immigration.
Emigrants and Immigrants , Passeriformes , Animals , Male , Humans , Female , Gene Flow , Population Dynamics
Ecological and evolutionary studies are currently failing to achieve complete and consistent reporting of model-related uncertainty. We identify three key barriers - a focus on parameter-related uncertainty, obscure uncertainty metrics, and limited recognition of uncertainty propagation - which have led to gaps in uncertainty consideration. However, these gaps can be closed. We propose that uncertainty reporting in ecology and evolution can be improved through wider application of existing statistical solutions and by adopting good practice from other scientific fields. Our recommendations include greater consideration of input data and model structure uncertainties, field-specific uncertainty standards for methods and reporting, and increased uncertainty propagation through the use of hierarchical models.
Ecology , Uncertainty , Ecology/methods
Quantifying uncertainty associated with our models is the only way we can express how much we know about any phenomenon. Incomplete consideration of model-based uncertainties can lead to overstated conclusions with real-world impacts in diverse spheres, including conservation, epidemiology, climate science, and policy. Despite these potentially damaging consequences, we still know little about how different fields quantify and report uncertainty. We introduce the "sources of uncertainty" framework, using it to conduct a systematic audit of model-related uncertainty quantification from seven scientific fields, spanning the biological, physical, and political sciences. Our interdisciplinary audit shows no field fully considers all possible sources of uncertainty, but each has its own best practices alongside shared outstanding challenges. We make ten easy-to-implement recommendations to improve the consistency, completeness, and clarity of reporting on model-related uncertainty. These recommendations serve as a guide to best practices across scientific fields and expand our toolbox for high-quality research.
Wetlands are among the most threatened habitats in the world, and so are their species, which suffer habitat loss due to climate and land use changes. Freshwater species, and especially arthropods, receive comparatively little attention in conservation plans, and the goals to stop and reverse the destruction of wetlands published 25 years ago in a manifesto by the Union of Concerned Scientists have not been reached. In this study, we investigated the occurrence and habitat requirements at two spatial scales of two species of European fishing spiders Dolomedes, which rely heavily on declining wetland habitats in Sweden and southern Norway. We collected occurrence data for Dolomedes plantarius and Dolomedes fimbriatus, using a live-determination method. We modelled the placement of nursery webs to describe fine-scale habitat requirements related to vegetation and micro-climate. Using a machine learning approach, we described the habitat features for each species and for co-occurrence sites, thus providing insight into variables relevant for the presence and detectability of Dolomedes. Nursery placement is mostly dependent on proximity to water, presence of Carex sp. (Sedges) and crossing vegetation structures, and on humidity, while detection can be affected by weather conditions. Furthermore, co-occurrence sites were more similar to D. plantarius sites than to D. fimbriatus sites, whereby surrounding forest, water type and velocity, elevation and latitude were of importance for explaining which species of Dolomedes was present. Overall, habitat requirements were narrower for D. plantarius compared to D. fimbiratus.
Hunting , Spiders , Animals , Ecosystem , Forests , Water
Immigration into small recipient populations is expected to alleviate inbreeding and increase genetic variation, and hence facilitate population persistence through genetic and/or evolutionary rescue. Such expectations depend on three standard assumptions: that immigrants are outbred, unrelated to existing natives at arrival, and unrelated to each other. These assumptions are rarely explicitly verified, including in key field systems in evolutionary ecology. Yet, they could be violated due to non-random or repeated immigration from adjacent small populations. We combined molecular genetic marker data for 150-160 microsatellite loci with comprehensive pedigree data to test the three assumptions for a song sparrow (Melospiza melodia) population that is a model system for quantifying effects of inbreeding and immigration in the wild. Immigrants were less homozygous than existing natives on average, with mean homozygosity that closely resembled outbred natives. Immigrants can therefore be considered outbred on the focal population scale. Comparisons of homozygosity of real or hypothetical offspring of immigrant-native, native-native and immigrant-immigrant pairings implied that immigrants were typically unrelated to existing natives and to each other. Indeed, immigrants' offspring would be even less homozygous than outbred individuals on the focal population scale. The three standard assumptions of population genetic and evolutionary theory were consequently largely validated. Yet, our analyses revealed some deviations that should be accounted for in future analyses of heterosis and inbreeding depression, implying that the three assumptions should be verified in other systems to probe patterns of non-random or repeated dispersal and facilitate precise and unbiased estimation of key evolutionary parameters.
Emigrants and Immigrants , Inbreeding Depression , Biological Evolution , Humans , Inbreeding , Pedigree
Ongoing adaptive evolution, and resulting "evolutionary rescue" of declining populations, requires additive genetic variation in fitness. Such variation can be increased by gene flow resulting from immigration, potentially facilitating evolution. But, gene flow could in fact constrain rather than facilitate local adaptive evolution if immigrants have low additive genetic values for local fitness. Local migration-selection balance and micro-evolutionary stasis could then result. However, key quantitative genetic effects of natural immigration, comprising the degrees to which gene flow increases the total local additive genetic variance yet counteracts local adaptive evolutionary change, have not been explicitly quantified in wild populations. Key implications of gene flow for population and evolutionary dynamics consequently remain unclear. Our quantitative genetic analyses of long-term data from free-living song sparrows (Melospiza melodia) show that mean breeding value for local juvenile survival to adulthood, a major component of fitness, increased across cohorts more than expected solely due to drift. Such micro-evolutionary change should be expected given nonzero additive genetic variance and consistent directional selection. However, this evolutionary increase was counteracted by negative additive genetic effects of recent immigrants, which increased total additive genetic variance but prevented a net directional evolutionary increase in total additive genetic value. These analyses imply an approximate quantitative genetic migration-selection balance in a major fitness component, and hence demonstrate a key mechanism by which substantial additive genetic variation can be maintained yet decoupled from local adaptive evolutionary change.
PURPOSE: This study aimed to investigate the supportive care needs of family caregivers (FCs) of advanced cancer patients and their support service use at the beginning of specialist inpatient palliative care (SIPC), near the patient's death, and during bereavement. METHODS: FCs reported their needs using the Family Inventory of Needs (FIN), along with their utilization of psychosocial and bereavement support services at the beginning (N = 232) and 6-9 months after SIPC (N = 160). RESULTS: At the beginning of SIPC, mean of 16.9 of 20 needs were reported to be highly important, and 12.2 were reported to be met. At the time of the patient's death, 16.8 needs were highly important, and 13.8 were met. At both time points, the highest ranked need was related to information about changes in the patient's condition (100% vs. 99%), and the most frequently unmet need was related to feeling hope (73% vs. 71%). Multivariate linear regression analysis revealed a low education level to be consistently related to a greater number of highly important needs. Higher satisfaction with care and better social support was related to a greater number of met needs. Twenty-five percent of FCs had accessed at least one psychosocial support service prior to SIPC, and 30% had done so during bereavement. Among non-users of support services, > 75% indicated sufficient informal support as a barrier to service use. CONCLUSIONS: The findings offer a useful guide for adequately addressing FCs' needs in an effort to optimize FC support. However, only a subgroup of the FCs used support services. Better information and provision of tailored services might improve FCs' situations in the future.
Caregivers/psychology , Palliative Care/psychology , Social Support , Terminal Care/psychology , Female , Humans , Longitudinal Studies , Male , Middle Aged , Prospective Studies
OBJECTIVE: To investigate prevalence and predictors of postloss distress, depressive and anxiety symptoms, and quality of life among bereaved family caregivers of patients with advanced cancer. METHODS: Prospective multicenter study. Family caregivers (N = 160, mean age 56.8 years, 66% female) completed validated outcome measures (Distress Thermometer, Generalized Anxiety Disorder 7-item scale, Patient Health Questionnaire depression module 9-item scale, SF-8 Health Survey Questionnaire) 6 months after patient's discharge or death at specialist inpatient palliative care ward. RESULTS: Clinically relevant distress was observed in 82% with sadness (89%), exhaustion (74%), sleeping problems (68%), loneliness (53%), and sorrows (52%) being the most common distress-causing problems. Moderate/severe anxiety and depressive symptoms were observed in 27% and 35%, respectively. Compared to an adjusted norm sample, quality of life was significantly impaired with exception of "bodily pain" and physical component score. Preloss caregiving (odds ratio [OR] 2.195) and higher preloss distress (OR 1.345) predicted high postloss distress. Utilization of psychosocial support services (OR 2.936) and higher preloss anxiety symptoms (OR 1.292) predicted moderate/severe anxiety symptoms, lower preloss physical quality of life (OR 0.952), and higher preloss depressive symptoms (OR 1.115) predicted moderate/severe depressive symptoms. CONCLUSION: Preloss mental burden showed to be a consistent predictor for postloss burden and should be addressed during palliative care. Future research should examine specific caregiver-directed interventions during specialist palliative care.
Caregivers/psychology , Family/psychology , Grief , Neoplasms/mortality , Neoplasms/psychology , Quality of Life/psychology , Adult , Aged , Aged, 80 and over , Anxiety Disorders/epidemiology , Depressive Disorder/epidemiology , Female , Forecasting , Humans , Male , Middle Aged , Prevalence , Prospective Studies , Stress, Psychological/epidemiology , Surveys and Questionnaires
BACKGROUND: This study prospectively evaluated distress, depressive and anxiety symptoms as well as associated factors in family caregivers (FC) of advanced cancer patients at initiation of specialist inpatient palliative care. METHODS: Within 72 h after the patient's first admission, FCs were asked to complete German versions of the Distress Thermometer, Generalized Anxiety Disorder 7-item scale (GAD-7), Patient Health Questionnaire depression module 9-item scale (PHQ-9) for outcome measure. Multivariate logistic regression analyses were used to identify associated factors. RESULTS: In 232 FCs (62% spouses/partners), mean level of distress was 7.9 (SD 1.8; range, 2-10) with 95% presenting clinically relevant distress levels. Most frequent problems were sadness (91%), sorrows (90%), anxiety (78%), exhaustion (77%) and sleep disturbances (73%). Prevalence rates of moderate to severe anxiety and depressive symptoms were 47 and 39%, respectively. Only 25% of FCs had used at least one source of support previously. In multivariate regression analysis, being female (OR 2.525), spouse/partner (OR 2.714), exhaustion (OR 10.267), and worse palliative care outcome ratings (OR 1.084) increased the likelihood for moderate to severe anxiety symptom levels. Being female (OR 3.302), low socio-economic status (OR 6.772), prior patient care other than home-based care (OR 0.399), exhaustion (OR 3.068), sleep disturbances (OR 4.183), and worse palliative care outcome ratings (OR 1.100) were associated with moderate to severe depressive symptom levels. CONCLUSIONS: FCs of patients presenting with indication for specialist palliative care suffer from high distress and relevant depressive and anxiety symptoms, indicating the high need of psychological support not only for patients, but also their FCs. Several socio-demographic and care-related risk-factors influence mental burden of FCs and should be in professional caregivers' focus in daily clinical practice.
Caregivers/psychology , Inpatients , Mental Health , Palliative Care/psychology , Adult , Aged , Aged, 80 and over , Anxiety/epidemiology , Depression/epidemiology , Female , Germany , Humans , Male , Middle Aged , Prospective Studies , Risk Factors , Sadness , Socioeconomic Factors , Stress, Psychological/epidemiology , Young Adult
