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PloS One 2023Many gibbon species are threatened with extinction, including the endangered northern yellow-cheeked crested gibbon, Nomascus annamensis. Assessing gibbon populations...
Density and population size estimates of the endangered northern yellow-cheeked crested gibbon Nomascus annamensis in selectively logged Veun Sai-Siem Pang National Park in Cambodia using acoustic spatial capture-recapture methods.
Many gibbon species are threatened with extinction, including the endangered northern yellow-cheeked crested gibbon, Nomascus annamensis. Assessing gibbon populations and understanding how human disturbances and environmental factors impact these populations is vital for effective conservation planning. In 2010, auditory surveys revealed that Veun Sai-Siem Pang National Park (VSSP) in Cambodia contains one of the largest known N. annamensis populations in the world, with an estimated 456 (95% CI 421-490) gibbon groups. Illegal selective logging is common in the park, but the impact of continued logging on the gibbon population has not been investigated. To determine any change in the N. annamensis population since 2010, between January and April 2019 we conducted auditory surveys at 13 sites that were at least 4 km apart. We surveyed each site for three days, each day recording the gibbon calls heard over 3.25 hours from three listening posts located 500 m apart. At the same sites, we assessed the logging intensity using transects and ecological plots. Gibbon densities can be influenced by various environmental factors such as canopy height and forest type. Therefore, in addition to investigating the relationship between the density of N. annamensis groups and logging, we included five additional environmental variables in our acoustic spatial capture-recapture models. Our best fit model with the lowest AIC value included canopy height, forest type, distance to villages, and logging. We estimate that there are 389 (95% CI 284-542) N. annamensis groups currently in VSSP. Selective logging is widespread in the park, primarily targeting four tree species. The estimated felling time of these logged trees, together with previous reports, indicate that the species most targeted in VSSP varies over time. To conserve the N. annamensis population in VSSP, it is crucial that action is taken to reduce illegal logging.
Topics: Animals; Humans; Hylobates; Population Density; Cambodia; Parks, Recreational; Conservation of Natural Resources; Trees
PubMed: 38011169
DOI: 10.1371/journal.pone.0292386 -
Sensors (Basel, Switzerland) Sep 2023Farm tractors have become a key part of daily routine agriculture, converting complex and time-consuming tasks into tasks that are easier to perform and less dependent...
Farm tractors have become a key part of daily routine agriculture, converting complex and time-consuming tasks into tasks that are easier to perform and less dependent on human labor, contributing directly to increasing the economic value generated by this activity sector, either by increasing the productivity or by making certain agricultural crops viable, which otherwise would not be sustainable. However, despite all the advantages, accidents with this type of equipment are common, often with critical and sometimes fatal consequences. The evolution of safety requirements of these machines has occurred at a good level; however, a significant part of the agricultural tractors in use are older models that do not have such solutions. Even in the new models, which contain such solutions, these are not always correctly used, and it is even common that they are turned off or simply not used at all. It is therefore natural that accidents continue to occur, a situation that is aggravated by other factors. Lack of situational awareness of the operators, which can result from advanced age, inadequate training, reduced sensitivity/respect for safety rules, or working on irregular terrain like mountainous areas, contribute to high-risk contexts that end in the loss of human life. The consequences of such accidents are clearly aggravated by the time it takes to assist the victims-either because accidents are simply not identified/reported immediately, or by the time it takes to locate and provide help to the victims. This is a scenario that is more common in mountainous regions and regions with low population density. The current paper, using NB-IoT, a set of sensors, and a web application, presents a conceptual toolset conceived to prevent accidents and minimize consequences (human and material) that can be applied to old and new farm tractors. The development was carried out taking the characterization of the farmers and the land in the region in which the authors' research institution is located into account, which has the highest rate of fatal accidents with agricultural tractors in the country; it is a region of mountainous with a very low population density.
Topics: Humans; Farms; Population Density; Accidents; Agriculture; Awareness
PubMed: 37765868
DOI: 10.3390/s23187811 -
Journal of Biological Dynamics Dec 2023People's lifestyles play a major role in disease risk. Some employment sectors and transport modes involve fixed exposures regardless of community size, while in other...
People's lifestyles play a major role in disease risk. Some employment sectors and transport modes involve fixed exposures regardless of community size, while in other settings exposure tracks with population density. MERS-CoV, a coronavirus discovered in Saudi Arabia in 2012 closely related to those causing SARS and COVID-19, appears to need extended contact time for transmission, making some segments of a community at greater risk than others. We model mathematically how heterogeneity in contact rate structure impacts disease spread, using as a case study a MERS outbreak in two Saudi Arabian communities. We divide the at-risk population into segments with exposure rates either independent of population density or density-dependent. Analysis shows disease spread is minimized for intermediate size populations with a limited proportion of individuals in the density-independent group. In the case study, the high proportion of density-independent exposure may explain the historical outbreak's extinction in the larger city.
Topics: Humans; COVID-19; Saudi Arabia; Models, Biological; Disease Outbreaks; Life Style
PubMed: 37523233
DOI: 10.1080/17513758.2023.2242389 -
Proceedings. Biological Sciences Aug 2023Climate change can severely impact species that depend on temporary resources by inducing phenological mismatches between consumer and resource seasonal timing. In the...
Climate change can severely impact species that depend on temporary resources by inducing phenological mismatches between consumer and resource seasonal timing. In the winter moth, warmer winters caused eggs to hatch before their food source, young oak leaves, became available. This phenological mismatch changed the selection on the temperature sensitivity of egg development rate. However, we know little about the fine-scale fitness consequences of phenological mismatch at the individual level and how this mismatch affects population dynamics in the winter moth. To determine the fitness consequences of mistimed egg hatching relative to timing of oak budburst, we quantified survival and pupation weight in a feeding experiment. We found that mismatch greatly increased mortality rates of freshly hatched caterpillars, as well as affecting caterpillar growth and development time. We then investigated whether these individual fitness consequences have population-level impacts by estimating the effect of phenological mismatch on population dynamics, using our long-term data (1994-2021) on relative winter moth population densities at four locations in The Netherlands. We found a significant effect of mismatch on population density with higher population growth rates in years with a smaller phenological mismatch. Our results indicate that climate change-induced phenological mismatch can incur severe individual fitness consequences that can impact population density in the wild.
Topics: Animals; Population Growth; Moths; Seasons; Population Dynamics; Climate Change
PubMed: 37608720
DOI: 10.1098/rspb.2023.0414 -
Journal of Women's Health (2002) Jun 2024Published studies have revealed challenges for people with human immunodeficiency virus (HIV) living in rural areas compared to those in urban areas, such as poor...
Published studies have revealed challenges for people with human immunodeficiency virus (HIV) living in rural areas compared to those in urban areas, such as poor access to HIV care, insufficient transportation, and isolation. The purpose of this study was to examine associations between population density and multiple psychosocial and clinical outcomes in the largest cohort of women with HIV (WWH) in the United States. Women's Interagency HIV Study (WIHS) participants from Southern sites ( = 561) in 2013-2018 were categorized and compared by population density quartiles. The most urban quartile was compared with the most rural quartile in several psychosocial and clinical variables, including HIV viral load suppression, HIV medication adherence, HIV care attendance, depression, internalized HIV stigma, and perceived discrimination in healthcare settings. Although women in the lowest density quartile were unexpectedly more highly resourced, women in that quartile had greater odds of not attending an HIV care visit in the last six months (odds ratio [OR] = 0.64, 95% confidence interval [CI] [0.43-0.95]), yet higher odds for having fully suppressed HIV when compared to women in the highest density quartile (OR = 1.64, 95% CI [1.13-2.38]). Highly urban WWH had greater likelihood of unsuppressed HIV, even after controlling for income, employment, and health insurance, despite reporting greater HIV care adherence and similar medication adherence. Further investigation into the reasons for these disparities by population density is needed, and particular clinical attention should be focused on individuals from high population density areas to help maximize their health outcomes.
PubMed: 38864119
DOI: 10.1089/jwh.2023.0698 -
PloS One 2023The present study aimed to assess the population density, structure, and population change of nine wild prey species in the semi-arid landscape of Saurashtra, Gujarat,...
The present study aimed to assess the population density, structure, and population change of nine wild prey species in the semi-arid landscape of Saurashtra, Gujarat, India. A total of eight sites, representing a gradient from highly protected woodlands and grasslands to unreserved grasslands, were selected for sampling. We employed the road transect methodology under a distance sampling framework to achieve our objectives. We evaluated the realized growth rate of the Gir ungulate population through linear regression analysis. Our findings revealed that deer species exhibited higher density and biomass in woodlands compared to grasslands and coastal forests. On the other hand, antelopes showed higher density and biomass in grasslands and coastal forests compared to woodlands. The density gradient of wild prey species was influenced by various factors, including habitat structure, social organization, grouping tendencies, and topography. Over the last four decades, the population of wild prey species in Gir showed minimal changes. Our study provides a comprehensive understanding of wild prey species' density and biomass patterns at the landscape level. The inclusion of findings from ecologically significant and unique areas, such as coastal forests, further enhances the importance of this study. The implications of this study extend beyond the conservation of wild prey species alone; they also contribute to the conservation of the large carnivore guild in the Saurashtra landscape.
Topics: Animals; Ecosystem; Biomass; Lions; Population Density; Conservation of Natural Resources; Deer; Forests; Carnivora
PubMed: 37768920
DOI: 10.1371/journal.pone.0292048 -
Public Health Nutrition Sep 2023Physical access to food may affect diet and thus obesity rates. We build upon existing work to better understand how socio-economic characteristics of locations are...
OBJECTIVE
Physical access to food may affect diet and thus obesity rates. We build upon existing work to better understand how socio-economic characteristics of locations are associated with childhood overweight.
DESIGN
Using cross-sectional design and publicly available data, the study specifically compares rural and urban areas, including interactions of distance from supermarkets with income and population density.
SETTING
We examine cross-sectional associations with obesity prevalence both in the national scale and across urban and rural areas differing in household wealth.
PARTICIPANTS
Children in reception class (aged 4-5) from all state-maintained schools in England taking part in the National Child Measurement Programme ( 6772).
RESULTS
Income was the main predictor of childhood obesity (adj. R-sq=.316, p<.001), whereas distance played only a marginal role (adj. R-sq=.01, p<.001). In urban areas, distance and density correlate with obesity directly and conditionally. Urban children were slightly more obese, but the opposite was true for children in affluent areas. Association between income poverty and obesity rates was stronger in urban areas (7·59 %) than rural areas (4·95 %), the former which also showed stronger association between distance and obesity.
CONCLUSIONS
Obesogenic environments present heightened risks in deprived urban and affluent rural areas. The results have potential value for policy making as for planning and targeting of services for vulnerable groups.
Topics: Child; Humans; Pediatric Obesity; Cross-Sectional Studies; Diet; Socioeconomic Factors; Rural Population; England; Urban Population; Overweight; Prevalence
PubMed: 37271723
DOI: 10.1017/S1368980023000952 -
PloS One 2023Roadways and railways can reduce wildlife movements across landscapes, negatively impacting population connectivity. Connectivity may be improved by structures that...
Roadways and railways can reduce wildlife movements across landscapes, negatively impacting population connectivity. Connectivity may be improved by structures that allow safe passage across linear barriers, but connectivity could be adversely influenced by low population densities. The Mojave desert tortoise is threatened by habitat loss, fragmentation, and population declines. The tortoise continues to decline as disturbance increases across the Mojave Desert in the southwestern United States. While underground crossing structures, like hydrological culverts, have begun receiving attention, population density has not been considered in tortoise connectivity. Our work asks a novel question: How do culverts and population density affect connectivity and potentially drive genetic and demographic patterns? To explore the role of culverts and population density, we used agent-based spatially explicit forward-in-time simulations of gene flow. We constructed resistance surfaces with a range of barriers to movement and representative of tortoise habitat with anthropogenic disturbance. We predicted connectivity under variable population densities. Simulations were run for 200 non-overlapping generations (3400 years) with 30 replicates using 20 microsatellite loci. We evaluated population genetic structure and diversity and found that culverts would not entirely negate the effects of linear barriers, but gene flow improved. Our results also indicated that density is important for connectivity. Low densities resulted in declines regardless of the landscape barrier scenario (> 75% population census size, > 97% effective population size). Results from our simulation using current anthropogenic disturbance predicted decreased population connectivity over time. Genetic and demographic effects were detectable within five generations (85 years) following disturbance with estimated losses in effective population size of 69%. The pronounced declines in effective population size indicate this could be a useful monitoring metric. We suggest management strategies that improve connectivity, such as roadside fencing tied to culverts, conservation areas in a connected network, and development restricted to disturbed areas.
PubMed: 37768995
DOI: 10.1371/journal.pone.0286820 -
Environmental Pollution (Barking, Essex... Aug 2023Green space is increasingly known to improve physical and mental health. Based on these benefits, green space might also be expected to help mitigate related harmful...
Green space is increasingly known to improve physical and mental health. Based on these benefits, green space might also be expected to help mitigate related harmful behavioral patterns, such as obsessive Internet use and relevant addictions. In response, we conducted a study on smartphone addiction, a new form of Internet addiction. We carried out a cross-sectional investigation in August 2022. We recruited 1011 smartphone users across China in August 2022, measured the Normalized Difference Vegetation Index (NDVI) in their residential neighborhoods (in 1, 2, and 3 km buffers), and captured data on smartphone addiction via the Smartphone Addiction Scale - Short version (SAS-SV). Potential mediators between green space and smartphone addiction, including physical activity, stress, and loneliness, were also reported by participants using the Physical Activity Rating Scale-3 (PRS-3), Depression, Anxiety and Stress Scale-21 (DASS-21), and 8-items UCLA Loneliness Scale (ULS-8). Multiple linear regression was employed to examine the relationships between green space and smartphone addiction. Structural equation modeling was performed to examine the potential pathways between these variables. Unexpectedly, NDVI in 1 km buffers was positively associated with smartphone addiction. By contrast, population density, an indicator of urbanization, was associated with lower levels of smartphone addiction in all NDVI buffer sizes. Meanwhile, we found NDVI was strongly associated with population density as well as other indicators of urbanization. Our findings are unexpected and suggest that greenness may serve as an indicator of urbanization at national levels and that urbanization may buffer against smartphone addiction. During the hot summer, green space and indoor facilities may have competitive land uses, so future research should examine whether this association exists in other seasons and scenarios. We also recommend alternative models to systematically evaluate the effects of different components of residential environments.
Topics: Humans; Internet Addiction Disorder; Cross-Sectional Studies; Parks, Recreational; Mental Health; Anxiety
PubMed: 37230169
DOI: 10.1016/j.envpol.2023.121852 -
Tropical Animal Health and Production Nov 2023Pedigree analysis is required to assess the genetic diversity and population structure of a close breeding population in order to effectively manage the breeding program...
Pedigree analysis is required to assess the genetic diversity and population structure of a close breeding population in order to effectively manage the breeding program and keep inbreeding under acceptable limits. Saanen × Beetal is a crossbred population of goats, reared at the National Dairy Research Institute (NDRI), Karnal, for the last five decades. This germplasm has been acclimated to a tropical climate and has a higher milk potential and prolificacy. The objective of this study was to elucidate the genetic diversity, population structure, and inbreeding in the flock of the Saanen × Beetal goats. The data were collected from the Animal Genetics and Breeding Division of ICAR-NDRI, Karnal, for 2603 animals from the year 1971 to 2021. Animals born between 2014 and 2017 were considered as a reference cohort. Results revealed that the average generation interval was 3.44 years for the complete pedigree. The average inbreeding coefficient and the average relatedness were 4.20% and 6.87%, respectively, for the complete pedigree and 10.78% and 10.80% for the reference population. Higher inbreeding coefficient and average relatedness in the reference cohort demonstrated the impact of the enclosed gene pool and demands immediate intervention for managing diversity in the closed nucleus under study. Ancestors contributing 50% of the gene pool were 8 and 3 for the complete pedigree and reference cohort, respectively, which illustrates the fact that very few ancestors were responsible for genetic diversity in the flock, which results in the decline of effective population size. Effective numbers of founders (f), ancestors (f), and founder genome equivalents (f) were 15, 7, and 3.11, respectively. The (f/f) ratio in the reference population was 2.14, indicating the occurrence of the bottleneck effect in the flock. We observed that inbreeding was non-significant for all reproductive traits except for age at first service and age at first kidding. To lessen inbreeding and augment genetic diversity in the flock, the stratified breeding plan needs to be followed, where mate selection would be based on relatedness. Furthermore, the introduction of unrelated Saanen and Beetal crosses will help alleviate the inbreeding accumulation.
Topics: Humans; Female; Animals; Genetic Variation; Pedigree; Goats; Inbreeding; Breeding; Population Density; Dermatitis; Goat Diseases
PubMed: 37921897
DOI: 10.1007/s11250-023-03807-w