Search Results (714)

Understanding species composition and forest dynamics is essential for predicting biomass productivity and informing conservation in tropical montane ecosystems. We evaluated floristic, demographic, and biomass changes in eighteen 0.1 ha permanent plots in the Colombian Sub-Andean forest, including both primary (ca. 60 y old) and secondary forests (ca. 30 years old). Two censuses of individuals (DBH ≥ 2.5 cm) were conducted over 7–13 years. We recorded 516 species across 202 genera and 89 families. Floristic composition differed significantly between forest types (PERMANOVA, p = 0.001), and black oak (Trigonobalanus excelsa Lozano, Hern. Cam. & Henao) forests formed distinct assemblages. Demographic rates were higher in secondary forests, with mortality (4.17% yr), recruitment (4.51% yr), and relative growth rate (0.02% yr) exceeding those of primary forests. The mean aboveground biomass accumulation and the rate of annual change were higher in primary forests (447.5 Mg ha⁻¹ and 466.8 Mg ha⁻¹ yr⁻¹, respectively) than in secondary forests (217.2 Mg ha⁻¹ and 217.2 Mg ha⁻¹ yr⁻¹, respectively). Notably, black oak forests showed the greatest biomass accumulation and rate of change in biomass. Annual net biomass production was higher in secondary forests (8.72 Mg ha⁻¹ yr⁻¹) than in primary forests (5.66 Mg ha⁻¹ yr⁻¹). These findings highlight the ecological distinctiveness and recovery potential of secondary Sub-Andean forests and underscore the value of multitemporal monitoring to understand forest resilience and assess vulnerability to environmental change. Full article

Human exploitation has been a major driver of marine turtle population declines, particularly affecting naturally scarce species such as the pantropical hawksbill turtle. Although hawksbill sea turtles have been documented in the Gulf of California since the early 20th century, data on their historical demography during periods of high exploitation in this region are nonexistent. We investigated the size structure of hawksbill turtles from the Western Central Gulf of California by examining a unique sample of decorative taxidermies, corresponding to 31 specimens captured during fishing operations near Santa Rosalía, Baja California Sur, Mexico, between 1980 and 1990. An analysis of the curved carapace measures revealed a length range (nuchal notch to posterior of supracaudals) of 29.5–59.5 cm (mean = 38.75 ± 6.67 cm) and a width range of 25.0–51.5 cm (mean = 33.63 ± 5.66 cm), with 87% of specimens having lengths between 30 and 45 cm. Based on the carapace length measurements, we estimated the ages to be between 7 and 20 years, indicating that the population included juveniles. Our findings provide baseline data for an understudied period and region, suggesting that this area previously served as an important juvenile habitat. These results contribute essential historical demographic information for conservation planning. Full article

The article addresses the question of the relative importance of human population size and growth in relation to the environmental problems of planetary heating and biodiversity loss in the current, Anthropocene era. To what extent could policies to encourage lower fertility be justified, while observing that this subject is an inherently contested one. It is proposed that a helpful distinction can be made between specific threats to habitats and biodiversity, as opposed to those related to global energy use and warming. Pressures of over-population can be important in relation to the former. But with regard to the latter—rising per capita energy usage—reduced fertility has historically been positively, not negatively correlated. A case can be made that the high-fertility nations of sub-Saharan Africa could benefit from culturally respectful fertility reduction policies. However, where planetary heating is concerned, it is the hydrocarbon-based, per capita energy-consumption patterns of already low-fertility populations on the other five inhabited continents that is rather more critical. While it will be helpful to stabilise global human population, this cannot be viewed as a solution to the climate crisis problem of this century. That requires relentless focus on reducing hydrocarbon use and confronting the rising inequality since c.1980 that has been exacerbating competitive materialist consumerism. This involves the ideological negotiation of values to promote a culture change that understands and politically embraces a new economics of both human and planetary balance, equity, and distribution. Students of populations can contribute by re-assessing what can be the appropriate demographic units and measures for policies engaging with the challenges of the Anthropocene. Full article

Leeches hold significant medical and pharmaceutical value for antithrombotic treatments, yet their genetic diversity patterns remain poorly understood. We performed population genetic analyses on seven Hirudinaria manillensis populations from southern China using mitochondrial protein-coding genes (MitPCGs). Complete sequences of all 13 MitPCGs were obtained from 74 individuals. Haplotype diversity exhibited a logarithmic relationship with the gene length (R² = 0.858, p < 0.001), while nucleotide diversity showed a near-perfect alternating low-high pattern (Z = 2.938, p = 0.003). Concatenated sequence analyses indicated high haplotype diversity (>0.5) and low nucleotide diversity (<0.005) across all populations, suggesting a historical bottleneck followed by rapid expansion and mutation accumulation. The haplotype network, haplotype phylogenetics, and genetic structure analyses revealed moderate genetic differentiation across populations, dividing them into three clades: a basal Yunnan population (YNHH), sub-basal Guangxi populations (GXGG, GXLZ, and GXYL), and distal Guangdong/Hainan populations (GDMM, GDZJ, and HNDA). Analysis of historical population demography revealed five phases from ancient to recent times (P1–5): growth, prolonged stability, rapid decline, rapid growth, and secondary decline. These phases correlate strongly with past climatic events, demonstrating that glacial–interglacial cycles profoundly impacted the leech’s effective population size. This study provides a key scientific basis for H. manillensis resource conservation and utilization. Full article

This article presents a new evaluation and analysis of the five censuses undertaken at the initiative of philanthropist Sir Moses Montefiore among the Jewish population of Palestine/the Land of Israel between 1839 and 1875. The main purpose of the censuses was to ascertain the composition and needs of a generally poor Jewish population in order to better provide to its welfare. The information collected concerned basic demographic characteristics, countries of origin—namely along the main divide of Ashkenazi and Sephardi/Mizrahi Jews—and periods of immigration, social composition, and religiosity. By combining the different censuses into an integrated database, the authors are able to show changes intervening over time not only regarding the aggregate population, but also concerning individual and household profiles. The data aggregation allows us to better understanding the material conditions of the Jewish population and to outline with greater accuracy the relationship between socio-cultural communities and socio-economic stratification. The analysis unveiled the patterns of Jewish immigration all along the surveyed period and its variations by size and by countries of origin. These data provide important evidence concerning the overall Jewish presence in the Land of Israel and demonstrate that immigration was a significant factor well before the formal beginning of Aliyah in the early 1880s. No such analysis of the whole set of Montefiore censuses had been performed previously. The findings will prove very useful to historians and social scientists in their further investigation of the area and its populations in the 19th century. Full article

Studies on the demography and health of racially diverse African populations are scarce, particularly due to lingering data challenges. Generative data modelling has emerged as a valuable solution to this burden. The study, therefore, examined the efficacy of Conditional Tabular GAN (CTGAN), CopulaGAN, and Tabula Variational Autoencoder (TVAE) for generating synthetic but realistic demographic and health data. This study employed the World Health Organisation stigy on global ageing and adult health survey (SAGE) Wave 1 South African data (n = 4227). Information missing from SAGE Wave 1, including demographic (e.g., race, age) and health (e.g., hypertension, blood pressure) indicators, were imputed using Generative Adversarial Imputation Nets (GAIN). CopulaGAN, CTGAN, and TVAE, sourced from the sdv 1.24.1 python library, generated 104,227 synthetic records based on the SAGE data constituents. The outcomes were accessed with similarity and machine learning (XGBoost) augmentation metrics (sourced from the sdmetrics 0.21.0 python library), including column shapes and overall and precision ratio scores. Generally, the GAIN imputations resulted in data with properties that were comparable to original and with no missing information. CTGAN’s (89.20%) overall quality of performance was above that of TVAE (86.50%) and CopulaGAN (88.45%). These findings underscore the usefulness of generative data modelling in addressing data quality challenges in diverse populations to enhance actionable health research and policy implementation. Full article

The study of plant demography is important for identifying ongoing population processes and trends. While single-census studies have limited ability to capture long-term dynamics, they are crucial for establishing baseline data on the status of plant populations. In 2022, four populations of Cephalanthera longifolia (Orchidaceae) in Lithuania were studied using a standardised sampling plot method. Within each population, 20 plots were established along a transect. All plant species within each plot were recorded, and their coverage was estimated. Additionally, the height of the plants, the cover of plant debris, and the amount of bare soil in the sampling plot were assessed. Vegetative individuals of C. longifolia were dominant across all populations, comprising between 58.7% and 85.1% of all individuals. Combining data from all populations revealed that vegetative individuals accounted for 71.8% of the total population, while generative individuals accounted for the remaining 28.2%. The mean density of individuals in the studied populations ranged from 3.8 ± 2.3 to 11.1 ± 4.3 individuals per square metre. A comparison of plant traits (plant height, inflorescence length, number of flowers in inflorescence, number of fruits set, and number of leaves) was performed between populations. Increased cover of plant debris was found to have the strongest negative effect on the number of individuals. We believe that the demographic type of a population (dynamic, normal or regressive) should be assessed in the context of the life cycle of certain species and their ecological traits, rather than mechanistically. Under reduced light availability, most individuals remained in a vegetative state. Therefore, the ratio of generative to vegetative individuals reflects current habitat conditions rather than long-term population trends. Full article

This study examines the feasibility of implementing circles of support for persons with disabilities within social service centers in Poland as a systemic solution promoting community-based support. The research follows the action research approach, combining theory and practice through participant involvement, reflection, cooperation, and change-oriented actions to address analyzed problems. The authors developed and tested the model in two diverse municipalities, analyzing legal, financial, and organizational dimensions. Results demonstrate that circles of support are legally feasible and financially sustainable, with approximate annual costs per participant comparable across different organizational models. Main challenges include limited funding and staff, especially in rural areas. Despite this, the model supports deinstitutionalization and can improve social inclusion, independence, and quality of life for people with disabilities. The study highlights the need for stable funding, thorough staff training, and coordination of formal and informal support, offering practical recommendations for scaling up such services in Poland. Full article

The role of abiotic factors in the allelopathic interactions between copepods and rotifers is poorly documented. Temperature has a marked effect on the metabolism of zooplankton. Therefore, the release of allelochemicals by copepods and the response of rotifers to them may change as temperatures increase. Here, we tested the effect of two temperatures (20 and 25 °C) on the population growth of Brachionus havanaensis cultured on a conditioned medium (CM) of Arctodiaptomus dorsalis and Eucyclops sp. The CM was obtained daily, separately, for the males and females of both copepod species at a density of 0.1 ind. mL⁻¹ for 24 h prior to experiments. In the controls and CM treatments, higher temperatures had a stimulatory effect on the population growth and the rate of population increase (r) of B. havanaensis. At 25 °C, the CM from the females and males of A. dorsalis caused >30% increase in r, but for the CM from Eucyclops sp., this effect was lower (<21%). At 20 °C, the r in the controls and CM treatments was not significantly different. The morphometry of B. havanaensis varied depending on the treatments. Compared to controls, longer loricae were recorded in the CM of male A. dorsalis at both temperatures. However, in the CM of female calanoids, longer rotifers were observed only at higher temperatures. At 20 °C, the CM from Eucyclops produced smaller loricae. The relationship between the lorica length and width of rotifers showed a linear relation but the slope differed among the treatments. Full article

The age-based life history of two commercially important parrotfishes (Labridae: tribe Scarinae) and one goatfish (Mullidae) were characterized based on the commercial nearshore fishery in Saipan, Commonwealth of the Northern Mariana Islands. Age, growth, reproduction, and mortality were derived from fishery-dependent samples using sagittal otoliths and gonads for the stareye parrotfish Calotomus carolinus, pacific bullethead parrotfish Chlorurus spilurus, and yellowfin goatfish Mulloidichthys vanicolensis. All three species had short lifespans of 10 years or less, with a maximum age of 4 years for C. carolinus, 10 years for C. spilurus, and 7 years for M. vanicolensis. All three species had a fast initial growth to terminal body sizes, early maturation, and spawned throughout the year. The age-based demographic information presented here can be used to inform future stock assessments, fisheries management, and population models. Full article

Intersectionality, especially with a race–class–gender focus, has been used to study many facets of women’s experiences. However, this framework has been underutilized in the study of breastfeeding prevalence. Our study is the first of its kind to use intersectionality to illuminate breastfeeding network prevalence disparities with empirical data. We use insights from this theory to examine breastfeeding patterns reported by women living on the Mississippi Gulf Coast. Mississippi makes an excellent site for such an examination, given its history of racial discrimination, entrenched poverty, and strikingly low rates of breastfeeding, particularly for African American women. We identify a series of factors that influence racial disparities in lactation network prevalence, that is, breastfeeding among friends and family of the women we surveyed. Our investigation relies on survey data drawn from a random sample of adult women who are representative of the Mississippi Gulf Coast population supplemented by a non-random oversample of African American women in this predominantly rural tri-county area. Results from the first wave of the CDC-funded 2019 Mississippi REACH Social Climate Survey reveal that Black-White differentials in breastfeeding network prevalence are significantly reduced for African American women who report (1) higher income levels and (2) more robust community support for breastfeeding. We conclude that breastfeeding is subject to two key structural factors: economic standing and community context. An appreciation of these intersecting influences on breastfeeding and long-term efforts to alter them could bring about greater breastfeeding parity among African American and White women in Mississippi and perhaps elsewhere. We end by identifying the practical implications of our findings and promising directions for future research. Full article

The diverse topography and mild monsoon climate in East Asia are considered to be important drivers for the long-term ecological success of the Tertiary relict ‘living fossil’ plants during the glacial/interglacial cycles. Here we investigated the phylogeographic pattern and demographic history of a hamamelidaceous Tertiary relict ‘living fossil’ tree (Parrotia subaequalis) endemic to the subtropical forests of eastern China, employing molecular data and ecological niche modeling. In the long evolutionary history, P. subaequalis has accumulated a high haplotype diversity. Weak gene flow by seeds, geographical isolation, and heterogeneous habitats have led to a relatively high level of genetic differentiation in this species. The divergence time of two cpDNA lineages of P. subaequalis was dated to the late Miocene of the Tertiary period, and the diversification of haplotypes occurred in the Quaternary period. Paleo-distribution modeling suggested that P. subaequalis followed the pattern of ‘glacial expansion-interglacial compression’. The Dabie Mountain and Yellow Mountain in Anhui Province and the Tianmu Mountain and Simin Mountain in Zhejiang Province were inferred to be multiple glacial refugia of P. subaequalis in East Asia and have been proposed to be protected as ‘Management Units’. Collectively, our study offers insights into the plant evolution and adaptation of P. subaequalis and other Tertiary relict ‘living fossil’ trees endemic to East Asia refugia. Full article

The increasing prevalence of emergency room (ER) visits for mental health concerns presents a significant challenge for healthcare systems. This study aimed to analyze the socio-demographic and clinical characteristics associated with frequent users of psychiatric consultations in the ER of Maggiore della Carità University Hospital in Novara, Italy. A retrospective observational study was conducted over a six-year period (2017–2022), including all psychiatric consultations recorded in a hospital database. Frequent users were defined as individuals undergoing at least three psychiatric consultations in the ER within a year. Univariable and multivariable logistic models were employed to identify significant socio-demographic and clinical predictors of frequent use. Of the 1565 individuals who received psychiatric consultations in the ER, 92 (5.88%) were identified as frequent users. Factors associated with higher ER utilization included being unmarried (aOR 1.35, 95% CI 1.02–1.79), younger age (aOR 1.32, 95% CI 1.02–1.72), homelessness, diagnosis of schizophrenia, substance use disorder (aOR 1.49, 95% CI 1.06–2.09), and ongoing psychopharmacological treatment (aOR 1.56, 95% CI 1.12–2.18). These findings highlight the need for targeted interventions to improve care continuity and community-based support for individuals at risk of frequent ER visits for psychiatric reasons. Full article

We report a landscape-scale natural experiment that followed the abundance and demography of forest-floor small mammals and the activity of small mustelids over a 4-year period of an extreme heat wave and abundant coniferous cone crops. Deer mice (Peromyscus maniculatus) and southern red-backed voles (Myodes gapperi) are major species in the coniferous forest-floor small mammal community near Summerland in southern British Columbia, Canada. Their major mammalian predators include the short-tailed weasel (Mustela richardsonii), long-tailed weasel (Neogale frenata), and American marten (Martes americana). We evaluated three hypotheses (H) that may explain the changes in these mammals from 2021 to 2024: (H₁) that large coniferous cone crops in 2022 would have generated high populations of forest-floor small mammals in 2023 owing to enhanced reproductive output and overwinter survival; (H₂) that increased activity of mustelids would have followed population increases, resulting in the decline of small mammal prey in 2024; and (H₃) that the widespread occurrence of cone crops in 2022 would also have elicited the same mammalian responses in 2023 at a second study area (Golden, BC) 276 km and three mountain ranges from Summerland. During the summer periods of each year, small mammal populations were monitored by intensive live-trapping, and mustelid presence was measured via an index of activity based on live traps, fecal scats, and predation events. The mean abundance and reproductive performance of the P. maniculatus and M. gapperi populations increased in response to the coniferous seedfall, thereby supporting H₁. The activity of small mustelids responded positively to increased numbers of small mammal prey and potentially acted in a regulatory and top–down function in these communities, and hence partially support H₂. Similar responses at Summerland and Golden indicated that this seedfall event and changes in the mammalian community occurred at a landscape-scale, thereby providing partial support for H₃. Potential differential effects of large seed crops on consumers did not affect the mean abundance patterns for P. maniculatus but apparently reduced this metric for M. gapperi. Heat waves, induced by anthropogenic climate change, may alter the frequency of coniferous masting events, and their effects may temporarily change the number and species of mammalian seed consumers and their predators. Full article

Objective: This study aimed to explore the association between adolescents’ health risk behaviours (excessive use of alcohol, (e)cigarette smoking, cannabis use) and familial factors. A special objective of this study was to compare findings between Bulgarian and Lithuanian adolescents aged 15 years. Material and Methods: National samples from the WHO Health Behaviour in School-aged Children (HBSC) survey in 2021/2022 were analysed. The focus was on adolescents aged 15 (n = 64,349), including those from Bulgaria (n = 793) and Lithuania (n = 1137). The set of outcome variables included drunkenness, smoked cigarettes, e-cigarettes, and used cannabis (all variables were measured during the last 30 days); their indicators were child’s talking separately to their father and separately to their mother, as well as the four-item family support scale. All variables were dichotomised and their associations were analysed using Structural Equation Modelling with a WLSMV estimator. Results: In the total sample, the prevalence of drunkenness was 14.9%, cigarette smoking at 12.6%, e-cigarette smoking at 18.4%, and cannabis use at 5.9%; while in Bulgaria, in contrast to Lithuania, these behaviours were much more prevalent, at 27.0%, 29.9%, 29.8%, and 11.1%, respectively. The use of substances was significantly associated with selected familial factors, which were more pronounced among girls than boys in most subsamples. Low family support showed the strongest association with increased substance use (in the total sample, regression weight B varied from 0.231 to 0.382). Adolescents’ difficulty in talking to mother was more pronounced (B = 0.123 to 0.204) than difficulty in talking to their father (B = 0.058 to 0.140). Comparison of data samples from Bulgaria and Lithuania showed stronger relationships in Bulgarian adolescents compared to other countries, which are more pronounced among boys. In addition, among Bulgarian adolescents, easy communication with their father had an inverse association (increasing prevalence) with cannabis use. Conclusions: Adolescent health risk behaviours, such as use of substances, are associated with familial factors, including parent–teen communication and family support. Generally, these associations are more pronounced among girls than boys, and more evident among Bulgarian adolescents than their Lithuanian counterparts. Identifying environmental factors in families helps to plan interventions to prevent development of multiple health risk behaviours in adolescents. Full article