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Bordoibam-Bilmukh is a small wetland located at the boundary of the Dhemaji and Lakhimpur districts of Assam, India that provides shelter and breeding ground to many resident and migratory birds. A survey was conducted between October 2022 and March 2024 on the avian diversity of Bordoibam-Bilmukh Bird Sanctuary. A total of 47 bird species under 16 orders and 29 families were recorded during the survey. Order Passeriformes, recorded with the highest number of avian species (15). Among the families, the highest number of species (5) was recorded under Ardeidae. Out of all the species recorded, three species, viz., Brown Shrike, Citrine Wagtail, and White Wagtail were winter migratory; one species, the Lesser Kestrel, was summer migratory, and the remaining 43 were resident species. Besides, two species, viz., Lesser Adjutant and Greater Adjutant are listed as 'Near Threatened' species on the IUCN Red List. Comparing the avian diversity from 1997 to 2024, a decline in the number of avian species from 167 (as per the 1997 record) to 47 (as per the present study) has been observed in the sanctuary. Various anthropogenic activities such as habitat destruction and disturbance, hunting of birds, are the major causes of the decline of avian diversity. For future species diversity restoration in the sanctuary, these negative anthropogenic activities should be addressed immediately for conservation strategies. [ABSTRACT FROM AUTHOR]

Bumblebees are a genus of pollinators (Bombus) that play important roles in natural ecosystem and agricultural production. Several bumblebee species have been recorded as under population decline, and the proportion of species experiencing population decline within subgenus Thoracobombus is higher than average. Bombus opulentus is 1 species in Thoracobombus, but little is known about its recent population dynamics. Here, we employed conservation genomics methods to investigate the population dynamics of B. opulentus during the recent past and identify the likely environmental factors that may cause population decline. Firstly, we placed the scaffold‐level of B. opulentus reference genome sequence onto chromosome‐level using Hi‐C technique. Then, based on this reference genome and whole‐genome resequencing data for 51 B. opulentus samples, we reconstructed the population structure and effective population size (Ne) trajectories of B. opulentus and identified genes that were under positive selection. Our results revealed that the collected B. opulentus samples could be divided into 2 populations, and 1 of them experienced a recent population decline; the declining population also exhibited lower genetic diversity and higher inbreeding levels. Genes related to high‐temperature tolerance, immune response, and detoxication showed signals of positive selection in the declining population, suggesting that climate warming and pathogen/pesticide exposures may contribute to the decline of this B. opulentus population. Taken together, our study provided insights into the demography of B. opulentus populations and highlighted that populations of the same bumblebee species could have contrasting Ne trajectories and population decline could be caused by a combination of various stressors. [ABSTRACT FROM AUTHOR]

Population decline due to low fertility and aging causes socioeconomic challenges such as a shrinking labour force and regional decline. In response to these challenges, there is a growing discussion about accepting immigrants to mitigate the side effects of population decline. This implies the importance of analyzing local peoples' perceptions as a basis of policy and planning in anticipation of demographic transitions toward a multicultural society. While there are many studies on local problems caused by depopulation and perceptions of immigrants based on contact theory and group threat theory, there has been relatively little research on the relationship between depopulation and individual perceptions of immigrants. This study fills this gap by using survey data of Seoul, Korea, the city experiencing both population decline and an increase in immigrants. It employs the multilevel ordered logit model to explore how the decrease in local population associates with individuals' perception on the need for multicultural immigration policies. The results suggest that individuals are more likely to have a positive view of multicultural immigration policies if their region is experiencing a higher population decline. This finding is significant as it demonstrates that a shift to an unfavourable demographic structure can have a positive impact on perceptions of immigrant acceptance, offering a new perspective on the relationship between immigrants and native residents. [ABSTRACT FROM AUTHOR]

Introduction: Hopea hainanensis Merrill & Chun is considered a keystone and indicator species in the tropical lowland rainforests of Hainan Island. Owing to its high-quality timber, H. hainanensis has been heavily exploited, leading to its classification as a first-class national protected plant in China and a plant species with extremely small populations (PSESPs). Methods: This study analyzed genome-wide single nucleotide polymorphisms obtained through restriction site-associated DNA sequencing from 78 adult trees across 10 H. hainanensis populations on Hainan Island. Results and discussion: The nucleotide diversity of the sampled populations ranged from 0.00096 to 0.00138, which is lower than that observed in several other PSESPs and endangered tree species. Bayesian unsupervised clustering, principal component analysis, and neighbor-joining tree reconstruction identified three to five genetic clusters in H. hainanensis, most of which were geographically widespread and shared by multiple populations. Demographic history analysis based on pooled samples indicated that the decline in the H. hainanensis population began approximately 20,000 years ago, starting from an ancestral population size of approximately 10,000 individuals. The reduction in population size accelerated approximately 4,000 years ago and has continued to the present, resulting in a severely reduced population on Hainan Island. Intensified genetic drift in small and isolated H. hainanensis populations may contribute to moderate differentiation between some of them, as revealed by pairwise Fst. In conclusion, our conservation genomic study confirms a severe population decline and an extremely low level of nucleotide variation in H. hainanensis on Hainan Island. These findings provide critical insights for the sustainable management and genetic restoration of H. hainanensis on Hainan Island. [ABSTRACT FROM AUTHOR]

Anthropogenic impact has transitioned from threatening already rare species to causing significant declines in once numerous organisms. Long‐tailed duck (Clangula hyemalis) and velvet scoter (Melanitta fusca) were once important quarry sea duck species in NW Europe, but recent declines resulted in their reclassification as vulnerable on the IUCN Red List. We sequenced and assembled genomes for both species and resequenced 15 individuals of each. Using analyses based on site frequency spectra and sequential Markovian coalescence, we found C. hyemalis to show more historical demographic stability, whereas M. fusca was affected particularly by the Last (Weichselian) Glaciation. This likely reflects C. hyemalis breeding continuously across the Arctic, with cycles of glaciation primarily shifting breeding areas south or north without major population declines, whereas the more restricted southern range of M. fusca would lead to significant range contraction during glaciations. Both species showed evidence of declines over the past thousands of years, potentially reflecting anthropogenic pressures with the recent decline indicating an accelerated process. Analysis of runs of homozygosity (ROH) showed low but nontrivial inbreeding, with FROH from 0.012 to 0.063 in C. hyemalis and ranging from 0 to 0.047 in M. fusca. Lengths of ROH suggested that this was due to ongoing background inbreeding rather than recent declines. Overall, despite demographically important declines, this has not yet led to strong inbreeding and genetic erosion, and the most pressing conservation concern may be the risk of density‐dependent (Allee) effects. We recommend monitoring of inbreeding using ROH analysis as a cost‐efficient method to track future developments to support effective conservation of these species. [ABSTRACT FROM AUTHOR]

The objective of this research was to describe the variation in breeding practices in the population of Arabian horses in Algeria in relation to the population size drop observed in the 2000s, due to an increase in the cost of food and a change in interest in racing, related to the black decade. As a result, the breeders had to face two opposite constraints: enhancing reproduction to counter the population decline and preventing the loss of genetic diversity. The aim of the study was to evaluate the genetic consequences of the decisions taken over a period of 30 years, starting from 1988 to 2018. The study was based on the analyses of the stud-book and on 11 microsatellite markers in a group of 943 horses, distributed into 13 age classes. Between 2004 and 2008, the breeders purchased foreign sires and dams, allowing a relative stability in unbiased heterozygosity of about 71%, due to the high genetic distances between foreign and local horses. As these importations stopped from 2009 on, there was a decrease in allele numbers of about 20%. Moreover, from 2010 on, we observe an excess of inbreeding and an increase in genetic drift relative to the starting population, due to population size decline. From the analysis of genetic distances between local individuals, it seems that the only constraint for sires and dams allowed to mate was a null coefficient of inbreeding. [ABSTRACT FROM AUTHOR]

Farmland habitats witness steep declines in biodiversity. One rapidly declining farmland species is the ortolan bunting Emberiza hortulana. In Finland, a staggering 99% of the population has been lost during the past 30 years. Changes in the breeding habitats have been proposed as a reason for the decline, although hazards during migration and wintering may also play a role. We gathered a 19‐year data set of Finnish ortolan buntings and studied which spatial characteristics, habitat features, and climate factors might explain the population growth rate at the singing‐group level. As explanatory variables we used region, density of small‐scale structures, proportion of agricultural area in the landscape, diversity of crop types, proportion of bare ground, and temperature and precipitation of previous breeding season. Higher population growth rates were associated with higher crop type diversity and higher proportion of bare ground. The mosaic of various crop plants and bare ground may provide a wider array of feeding, hiding and nesting places, and an easier access to food. Higher growth rates were also associated with landscapes dominated by interconnected agricultural land, which may reflect the species' sociability and avoidance of forested areas. The North Ostrobothnia region had higher growth rates compared to other regions. We suggest that northern populations of ortolan bunting should be targeted for further studies on feeding and breeding ecology as well as for urgent conservation actions, such as increasing crop type diversity and bare ground. [ABSTRACT FROM AUTHOR]

The Caucasian Parsley Frog, Pelodytes caucasicus (Boulenger, 1896), is endemic to Caucasia, and its population is decreasing. Here, we present information on the genetic structure and diversity of populations from four provinces of Türkiye (Giresun, Trabzon, Rize, and Artvin) using microsatellite markers. Despite their small geographic range, the species' populations showed moderate genetic differentiation, which could be a result of rapid genetic drift. Our results show that Trabzon and Giresun populations are genetically different from those of Rize and Artvin. We found considerably low genetic diversity in Artvin, Trabzon, and Giresun populations. The inbreeding co-efficient is also high in those localities (HO

This study first examines changes in the amount of residential area on a regional scale, which is said to shrink following population decline, using Japan as an example, where population decline is already underway in most of the country. Second, it examines how the regional governments have set future targets for residential areas and whether these targets are consistent with the current trend. Third, it examines how prefectures, Japan's regional governments, are responding to this situation through regional land use planning. The methodologies of the paper are a combination of collecting and sorting out the related data, reviewing and extracting information from planning documents, and conducting interviews with persons in charge. In conclusion, residential areas have continued to increase on a regional scale, even as the population has declined. Shrinkage does not follow population decline on a regional scale. It was also found that the amount of residential area changed more closely with the change in households than with the population. National and regional land use plans generally set targets for more shrinkage than the actual trend. The underestimation of the amount of residential area was due to the rapid decline in the number of persons per household. Cases of the three prefectures showed that specific control is left to the individual acts, while the measures are indicated in the wording by the prefectural land use plans. [ABSTRACT FROM AUTHOR]

Abstract Background Many municipalities in rural areas of Korea are facing population decline due to the aging population phenomenon. This study examined the relationship between residing in municipalities facing population decline and satisfaction with nearby healthcare infrastructure in older aged adults. Methods The 2021 Korea Community Health Survey (KCHS) data were used. Municipalities were classified as those not facing population decline, those at risk, and those facing population decline based on the Population Decline Index. The association between residing in municipalities facing population decline and satisfaction with nearby healthcare infrastructure was examined cross-sectionally using a multi-level logistic regression analysis. Satisfaction with available public transportation was concomitantly examined as it is related to accessing healthcare services. Results Of the 58,568 individuals aged 65 years or above analyzed, 27,471 (46.9%) adults were residing in municipalities without population decline, 4,640 (7.9%) adults in municipalities at risk of population decline, and 26,457 (45.2%) in municipalities with population decline. Individuals living in municipalities with population decline were more likely to be dissatisfied with nearby healthcare infrastructure (OR 1.76, 95% CI 1.41–2.20). Similar tendencies were found for public transportation infrastructure (OR 1.67, 95% CI 1.38–2.03). Conclusions Individuals residing in municipalities with declining populations are more likely to report dissatisfaction with nearby healthcare infrastructure and public transportation. These findings emphasize the importance of providing adequate medical infrastructure to reduce potential health-related disparities.

The myxoma virus species jump from European rabbits (Oryctolagus cuniculus) to Iberian hares (Lepus granatensis) has raised concerns. We assess the decline suffered by Iberian hare populations on the Iberian Peninsula and discuss the association between the effect of myxomatosis and the average abundance index, which we estimated by using hunting bags.

Despite the numerous food studies conducted in Detroit, none have assessed changes in the food landscape over a decade. No previous study has systematically analyzed food store closures in the city either. We will address these oversights by examining the distribution of food outlets in the city ten years apart. This paper probes the following questions: (1) How has the distribution of Detroit's food outlets changed in the decade between 2013 and 2023? (2) Does Detroit fit the definition of a food desert in 2013 or 2023? (3) Does Detroit fit the definition of a food swamp in 2013 or 2023? (4) Has supermarket redlining occurred in Detroit in 2013 or 2023? (5) How is population decline related to food outlet distribution? (6) How do food store closures impact food store distribution? We conducted exhaustive searches to collect information on thousands of food outlets from Data Axle, Google, and Bing. The data were analyzed and mapped in SPSS 28 and ArcGIS 10.8. We compared 3499 food outlets identified in 2013 with 2884 identified in 2023. We expanded our search for food outlets in 2023 and found an additional 611 food outlets in categories not studied in 2013. The study's findings are significant as they unearth evidence of extensive population decline—driven by Black flight—and a vanishing food infrastructure. Detroit lost more than 600 food outlets between 2013 and 2023, a staggering number that underscores the severity of the issue. Moreover, in 2023, we documented food store closures and found 1305 non-operational or closed food outlets in the city. Regardless of the neighborhood's racial composition, the household median income, or the educational attainment of residents, food store closures were widespread in 2023; 27.3% of the food outlets identified that year were defunct. Despite the massive food store closures, Detroit did not fit the description of a food desert; each of the city's 54 neighborhoods had between 7 and 300 food outlets. The food swamp thesis did not accurately describe the city either, as supermarkets/large grocery stores were intermingled with convenience and corner stores in both study periods. The data did not find evidence of supermarket redlining, as supermarkets/large grocery stores were found in formerly redlined neighborhoods alongside dollar stores and variety stores in both study periods. [ABSTRACT FROM AUTHOR]

The introduced Japanese weasel, Mustela itatsi, has had a significant negative impact on indigenous terrestrial vertebrates across several islands in the Miyako Group. The present study aimed to assess the current population status of squamate reptiles by investigating the distributions and abundances of three endangered lizards, Plestiodon kishinouyei, Takydromus toyamai, and Emoia atrocostata atrocostata, on Shimojijima Island and Irabujima Island. Route censuses for these species were conducted in the periods from 30 July to 4 August and 8–13 October 2022. Additionally, opportunistic sightings of lizards outside of the designated censuses were recorded. Eight P. kishinouyei, 20 T. toyamai, and seven E. a. atrocostata were recorded along four out of 101 survey routes, six out of 76, and two out of 39, respectively, with one additional E. a. atrocostata sighting at a non-census site. Plestiodon kishinouyei and E. a. atrocostata exhibited highly restricted distribution: the former was exclusively found in the northwestern part of Shimojijima Island, whereas the latter was confined to the southwestern part, with no presence on Irabujima Island. Takydromus toyamai was observed on both Shimojijima Island and Irabujima Island. The frequency of occurrence was low for the two skink populations on Shimojijima Island and T. toyamai on Irabujima Island, suggesting a potential population decline. These findings provide baseline data on the population status of these three lizard species. Such data will be crucial for evaluating their prospects for recovery, particularly considering the ongoing extensive eradication project targeting the introduced Japanese weasel on these islands. [ABSTRACT FROM AUTHOR]

Records from online biodiversity databases (including citizen science data) can play a crucial role in enhancing scientific knowledge about the abundance, distribution, and population trends of poorly studied species which are usually not properly monitored. This study aims to demonstrate the utility of data hosted in GBIF in detecting the likely decline of species common and widely distributed in the past, but whose conservation status is now uncertain, such as the weasel (Mustela nivalis) in Spain. To address this, we analyzed data on its presence in Spain from 2008 to 2022 available on GBIF.org, and compared it with the distribution data from the Atlas of Mammals of Spain published in 2007. The results indicate that: (i) data from GBIF.org reveal a moderate decline (negative trend) in the weasel population in Spain during the study period; (ii) the species has been recorded in a limited number of 10 × 10 km UTM-squares (Universal Transverse Mercator) within its distribution range as defined by the 2007 atlas; and (iii) there are large areas of Spain in which the species has not been detected in recent years. These findings highlight the concerning conservation status of this carnivorous species and underscore the value of data from open access platforms such as GBIF in identifying potential silent extinctions. [ABSTRACT FROM AUTHOR]

Background: Many municipalities in rural areas of Korea are facing population decline due to the aging population phenomenon. This study examined the relationship between residing in municipalities facing population decline and satisfaction with nearby healthcare infrastructure in older aged adults. Methods: The 2021 Korea Community Health Survey (KCHS) data were used. Municipalities were classified as those not facing population decline, those at risk, and those facing population decline based on the Population Decline Index. The association between residing in municipalities facing population decline and satisfaction with nearby healthcare infrastructure was examined cross-sectionally using a multi-level logistic regression analysis. Satisfaction with available public transportation was concomitantly examined as it is related to accessing healthcare services. Results: Of the 58,568 individuals aged 65 years or above analyzed, 27,471 (46.9%) adults were residing in municipalities without population decline, 4,640 (7.9%) adults in municipalities at risk of population decline, and 26,457 (45.2%) in municipalities with population decline. Individuals living in municipalities with population decline were more likely to be dissatisfied with nearby healthcare infrastructure (OR 1.76, 95% CI 1.41–2.20). Similar tendencies were found for public transportation infrastructure (OR 1.67, 95% CI 1.38–2.03). Conclusions: Individuals residing in municipalities with declining populations are more likely to report dissatisfaction with nearby healthcare infrastructure and public transportation. These findings emphasize the importance of providing adequate medical infrastructure to reduce potential health-related disparities. [ABSTRACT FROM AUTHOR]

Kaghaznagar and Sironcha Forest Divisions in the Deccan Plateau of India support large breeding colonies of critically endangered species of long-billed Gyps indicus (LBV) and white-rumped G. bengalensis (WRV) vultures. To assess their abundance and age-structure, that are important population parameters, they were surveyed every month at their breeding colonies; LBV at Palarapu cliff during 2010–2021 and Lakkameda cliff during 2015–2021, and WRV at Dechilpeta during 2014–2021. Breeding colonies of LBV supported a mean of 32 ± 1.3 individuals during 2015–2021. Although its number increased from 34 individuals in 2015 to 42 in 2017, it declined significantly to 10 in 2021. In contrast, WRV with a mean of 49 ± 3.35 individuals between 2014 and 2021 increased from 22 to 66. Data on the population structure show that adults constitute bulk of the population in both LBV (78 ± 1.2%) and WRV (80 ± 2.1%) with a low proportion of young age-classes of sub-adults, juveniles and chicks. With a declining trend and low proportion of young-age classes, the LBV breeding colonies are likely to decrease over time. Although WRV showed an increasing trend during the study period, the high adult proportion (80%) cannot guarantee its sustained growth. [ABSTRACT FROM AUTHOR]

ABSTRACT Anthropogenic impact has transitioned from threatening already rare species to causing significant declines in once numerous organisms. Long‐tailed duck (Clangula hyemalis) and velvet scoter (Melanitta fusca) were once important quarry sea duck species in NW Europe, but recent declines resulted in their reclassification as vulnerable on the IUCN Red List. We sequenced and assembled genomes for both species and resequenced 15 individuals of each. Using analyses based on site frequency spectra and sequential Markovian coalescence, we found C. hyemalis to show more historical demographic stability, whereas M. fusca was affected particularly by the Last (Weichselian) Glaciation. This likely reflects C. hyemalis breeding continuously across the Arctic, with cycles of glaciation primarily shifting breeding areas south or north without major population declines, whereas the more restricted southern range of M. fusca would lead to significant range contraction during glaciations. Both species showed evidence of declines over the past thousands of years, potentially reflecting anthropogenic pressures with the recent decline indicating an accelerated process. Analysis of runs of homozygosity (ROH) showed low but nontrivial inbreeding, with FROH from 0.012 to 0.063 in C. hyemalis and ranging from 0 to 0.047 in M. fusca. Lengths of ROH suggested that this was due to ongoing background inbreeding rather than recent declines. Overall, despite demographically important declines, this has not yet led to strong inbreeding and genetic erosion, and the most pressing conservation concern may be the risk of density‐dependent (Allee) effects. We recommend monitoring of inbreeding using ROH analysis as a cost‐efficient method to track future developments to support effective conservation of these species.

Farmland habitats witness steep declines in biodiversity. One rapidly declining farmland species is the ortolan bunting Emberiza hortulana. In Finland, a staggering 99% of the population has been lost during the past 30 years. Changes in the breeding habitats have been proposed as a reason for the decline, although hazards during migration and wintering may also play a role. We gathered a 19‐year data set of Finnish ortolan buntings and studied which spatial characteristics, habitat features, and climate factors might explain the population growth rate at the singing‐group level. As explanatory variables we used region, density of small‐scale structures, proportion of agricultural area in the landscape, diversity of crop types, proportion of bare ground, and temperature and precipitation of previous breeding season. Higher population growth rates were associated with higher crop type diversity and higher proportion of bare ground. The mosaic of various crop plants and bare ground may provide a wider array of feeding, hiding and nesting places, and an easier access to food. Higher growth rates were also associated with landscapes dominated by interconnected agricultural land, which may reflect the species' sociability and avoidance of forested areas. The North Ostrobothnia region had higher growth rates compared to other regions. We suggest that northern populations of ortolan bunting should be targeted for further studies on feeding and breeding ecology as well as for urgent conservation actions, such as increasing crop type diversity and bare ground.

Foundation species, such as trees, corals, grasses, oysters, and rockweeds, must be common and abundant to effectively modify the physical environment and increase biodiversity by buffering environmental stress. Yet many of these important species have been declining due to disease, climate change, and other factors. A prime example is the precipitous population decline of marine rockweeds, which is attributed to increased urbanization and its accompanying impacts. Rockweeds provide three-dimensional habitat in harsh rocky intertidal environments and regulate ecosystem functioning, essential roles that no substitute species are capable of filling. Recovery of impacted rockweed populations is typically slow and unpredictable due to their limited dispersal capacity. These issues have motivated efforts to conserve remaining populations of rockweeds and reestablish or enhance depleted ones. Successfully doing so requires a robust understanding of factors that affect survival of the species and the processes that influence ecosystem structure, along with rigorous scientific testing of restoration methods and the factors that affect restoration success. In this comprehensive review, we summarize the current knowledge of rockweed ecology, highlight studies that could inform restoration practices, and recommend ways to improve our ability to implement scalable restoration of rockweeds and accompanying ecosystem-wide benefits.

The McKay's Bunting (Plectrophenax hyperboreus) is endemic to Alaska, breeds solely on the remote and uninhabited St. Matthew and Hall islands (332 km2) in the central Bering Sea, and is designated as a species of high conservation concern due to its small population size and restricted range. A previous hypothesized population estimate (~2,800 to 6,000 individuals) was greatly increased (~31,200 individuals) after systematic surveys of the species' entire breeding range in 2003, establishing McKay's Bunting as one of the rarest passerines in North America. In 2018, we replicated the 2003 surveys and used density surface models to estimate breeding season densities, distributions, and population change over the intervening time period. Our results indicate that the McKay's Bunting population declined by 38% (95% CI: 27 to 48%) from ~31,560 to 19,481 individuals since 2003. Spatial model predictions showed no areas with an increase of birds on either St. Matthew or Hall islands but revealed declines across 13% (42 km2) of St. Matthew Island. Declines disproportionately occurred both in marginal habitats with reduced rocky nesting substrate and in high-density hotspots along the coast of St. Matthew Island. The total area occupied by breeding adults decreased by 8%, and high-density hotspots shifted inland from the coast of St. Matthew Island to higher elevations on both islands, the latter potentially responses to exceptionally warm weather and reduced spring snow cover in 2018. Additionally, we observed low numbers of predators and interspecific competitors in 2018, suggesting that these did not cause the decline. Our findings indicate that McKay's Bunting meets international standards for elevating its conservation status from Least Concern to Endangered based on the International Union for Conservation of Nature Red List of Threatened Species ranking criteria. Additional population monitoring and studies to identify the causal mechanisms of the recent population decline of this rare species could assist future population assessments. [ABSTRACT FROM AUTHOR]

Titanium dioxide nanoparticle (TiO2-NP) exposure has raised significant concern due to their potential toxicity and adverse ecological impacts. Despite their ubiquitous presence in various environmental compartments, the long-term consequences of TiO2-NPs remain poorly understood. In this study, we combined data of in vivo toxicity and modeling to investigate the potential negative impacts of TiO2-NP exposure. We employed the nematode Caenorhabditis elegans, an environmental organism, to conduct a full life cycle TiO2-NP toxicity assays. Moreover, to assess the potential impact of TiO2-NP toxicity on population dynamics, we applied a stage-constructed matrix population model (MPM). Results showed that TiO2-NPs caused significant reductions in reproduction, survival, and growth of parental C. elegans (P0) at the examined concentrations. Moreover, these toxic effects were even more pronounced in the subsequent generation (F1) when exposed to TiO2-NPs. Furthermore, parental TiO2-NP exposure resulted in significant toxicity in non-exposed C. elegans progeny (TiO2-NPs free), adversely affecting their reproduction, survival, and growth. MPM analysis revealed decreased transition probabilities of surviving (Pi), growth (Gi), and fertility (Fi) in scenarios with TiO2-NP exposure. Additionally, the population growth rate (λmax) was found to be less than 1 in both P0 and F1, indicating a declining population trend after successive generations. Sensitivity analysis pinpointed L1 larvae as the most vulnerable stage, significantly contributing to the observed population decline in both P0 and F1 generations under TiO2-NP exposure. Our findings provide insight into the potential risk of an environmental organism like nematode by life cycle exposure to TiO2-NPs. [ABSTRACT FROM AUTHOR]

The United Nations' 2022 World Population Prospects suggests the global population will reach 10 billion people in 2058 and will peak in 2086. Aggregated data do not account for regional and age-group realities, which draw a more pressing picture. We analyze the World Population Prospects 2022 data according to age groups and regions and show that population peaks are going to occur sooner in some regions of the world than others, and the working-age population will peak on average 10 to 20 years before the overall population peaks. Africa is the only world region expected to continue to experience significant population growth. The population will be increasingly made up of larger proportions of older ages than younger, thereby shifting the dependency ratio. Reflections on the implications of an aging and shrinking population on policy regarding fertility, aging, migration, urban planning and economic development are needed. The challenge is not to be left for future generations to face; it is happening tomorrow. [ABSTRACT FROM AUTHOR]

The Northern Bobwhite (Colinus virginianus) has been undergoing a range-wide population decline. Potential causes for declines across its historic range have been investigated for decades and include habitat loss and fragmentation and a variety of parasitic and infectious diseases. Although there have been studies on bobwhite ecology in Oklahoma, USA, relatively little is known about parasites and pathogens in the region. We evaluated the health of free-ranging bobwhites from nine sites in western Oklahoma. From 2018 to 2020, 206 bobwhites were evaluated for gross and microscopic lesions and tested for selected pathogens. In general, bobwhites were in good nutritional condition with ample muscle mass and fat stores. No significant gross lesions were observed in any bobwhite and no significant histologic lesions were detected in a subset. There was no evidence of infection with or exposure to reticuloendotheliosis virus, West Nile virus, respiratory Mycoplasmataceae species, Pasteurella multocida, intestinal Eimeria spp., or oral Trichomonas spp. Several pathogens of potential concern were detected, including avian adenovirus (8.6%), Toxoplasma gondii (2.3%), and haemosporidians (a Haemoproteus sp. (1.5%), Leucocytozoon schoutedeni (1.5%), and Plasmodium homopolare haplotype 2 [lineage LAIRI01; 3.6%]). Physaloptera sp. (12%) and Sarcocystis sp. (1%) were detected in the breast muscle. Low intraspecific genetic diversity was noted for Physaloptera sp., and sequences were most similar to Physaloptera sequences from bobwhites and grasshoppers (Orthoptera) in Texas. Low intensities of chewing lice, chiggers, and ticks were observed. A subset of bobwhites had evidence of exposure to selected toxicants and heavy metals; a small number had low levels of iron, manganese, zinc, molybdenum, and copper, which were not considered diagnostically relevant. In general, bobwhites from western Oklahoma appeared to be in good health with a low diversity of pathogens detected, but future work is needed to understand potentially changing disease risks for this population. [ABSTRACT FROM AUTHOR]

When will the human population peak? In this article, we build on classical results by Ansley Coale, who showed that when fertility declines steadily, births reach their maximum before fertility reaches replacement level, and the decline in total population size does not occur until several decades after fertility has reached that level. We extend Coale's results by modeling longevity increases, net immigration, and a slowdown in fertility decline that resembles current projections. With these extensions, our models predict a typical lag between replacement-level fertility and population decline of about 35 to 40 years, consistent with projections by the United Nations and about 15 years longer than the lag predicted by Coale. Our analysis helps reveal underlying factors in the timing of peak population. [ABSTRACT FROM AUTHOR]

The question of Tahiti population at contact was first addressed by assessing the reliability of early and later estimates, and then by a retrodiction based on the first reliable censuses and data on trends. Cook's famous estimate of 204,000 Tahitians, affected by a wrong number of districts, has been reworked based on his own and the Forsters' observations, using coast length and the age and sex structure of Tahiti population at contact in relation to infanticide, resulting in a range of 156,000-188,000 persons in 1774, before Boenechea's flu in 1772 and the 1774 flu epidemics. The discrepancies between Wilson's 16,050 and other missionaries' estimate of 50,000 as of 1797 are puzzling, but the 1829-1830 missionary estimates were strongly affected by Tahitians' resistance to Christianization. The twentieth century estimates are affected by a political context related to colonization - decolonisation, leading to the fact that researchers favour low estimates. McArthur uses missionary data, assuming that baptisms are births, although before the conversion was completed, baptisms included adults and children of all ages. She bases her estimate of 30,000 Tahitians at contact in 1767 on Wilson's number of 16,050, who applied the size of nuclear households, 6 persons, to clans. Oliver followed her, however not excluding numbers twice as high or more. Our retrodiction on the 1848 and 1881 censuses, based on qualitative missionary reports on sanitary situation and data of Rarotonga that experienced similar events as Tahiti, yield, with conservative assumptions, 180,000 persons at contact, showing consistent results with early navigators' estimates. My own PhD experience in the late 1980s shows that scholars' re-estimates were constrained, directly or indirectly, by political considerations related to the guilt syndrome and colonialist ideology. This appears in the frequent contradictions found in their works to support low estimates in order to reduce the decline, despite evidence of dramatic epidemics and a steady decline extending almost throughout the 19th century. The same attitude of denial is found in some missionary, administrative and medical reports, particularly on the Marquesas in the late 19th century. Colonisation was associated with various ideologies, related to anthropology's early attempts based on theories of evolutionism, functionalism and structuralism, occasionally resulting in fictions such as "primitive thinking", "ahistorical societies" and "collective unconscious", that were part of the justification of colonisation and its mistakes. [ABSTRACT FROM AUTHOR]

Over the past half a century many countries have witnessed a rapid fall in total fertility rates, particularly in the world's most advanced economies including the industrial powerhouses of Eastern Asia and Europe. Such nations have now passed through the first and second demographic transitions and are currently exhibiting fertility rates well below the replacement threshold of 2.1, with no sign of recovery. This paper examines the factors responsible for driving these demographic transitions and considers their impact on both fertility and fecundity (our fundamental capacity to reproduce). I argue that because the first demographic transition was extremely rapid and largely driven by socioeconomic factors, it has had no lasting impact on the genetic/epigenetic underpinnings of human fecundity. However, the second demographic transition will be different. A series of conditions associated with low fertility societies, including relaxed selection pressure for high-fertility genotypes, the indiscriminate use of assisted reproductive technologies to treat human infertility, and environmental contamination with reproductive toxicants, may impact our genetic constitution in ways that compromise the future fecundity of our species. Since any fundamental change in the genetic foundations of human reproduction will be difficult to reverse, we should actively pursue methods to monitor human fecundity, as sub-replacement fertility levels become established across the globe. [ABSTRACT FROM AUTHOR]

Depopulation is caused by low fertility rates and out-migration, and it applies to countries, regions and smaller areas. Rural depopulation is defined as a sharp population decline that falls well below an adequate population size and indicates that an area has lost its demographic reproductive capacity. This paper discusses the socioeconomic and territorial aspects of rural depopulation, attempting to do justice to the spatial dimensions of the phenomenon. Greece exhibits all the symptoms of demographic transition, leading to labour shortages, declining economic productivity, and increasing demands on the health and welfare system. The study on rural depopulation in Greece focuses on the changes and dynamics observed at the municipal and regional levels. A typology has been developed to identify rural communities in Greece. The main source of demographic data for our study is the Greek censuses (1991, 2001, 2011, and 2021). Demographic and socioeconomic trends in Greece are interlinked and show different regional and local dynamics. Rural depopulation is closely related to the study of (international and internal) migration, even though the latter does not provide a permanent solution to depopulation. An empirical analysis has shown that there is a need to revitalise rural areas through socioeconomic improvements, infrastructure investments, and policies that directly impact rural communities. [ABSTRACT FROM AUTHOR]

In the last thirty years, the countries of south-eastern and eastern Europe have experienced significant population decline, and Croatia is no exception to that. This paper revisits the problem of depopulation in Croatia in the last two intercensal periods (2001–2011 and 2011–2021). The aim was to analyze the impact of emigration on depopulation in Croatia and investigate whether it had a greater impact on depopulation than natural decrease. Additionally, the aim was to investigate whether the number of emigrants was underreported in the official statistics. The results show that Croatia lost more population due to negative net migration than the official statistical data indicate. Recent migrations in Croatia did not only affect the population decline, but also age composition of the population, particularly in the last intercensal period due to emigration of families with children and population in their working and reproductive ages, as they composed a large proportion of emigrants. The paper provides an elaborate insight into the recent migration patterns in Croatia while highlighting the underestimation of the proportions of emigration from Croatia by the official statistics.

AbstractA rapid decline of Abies koreana has been reported in most of the natural alpine habitats in Korea. It is generally accepted that this phenomenon is due to climate change even though no clear conclusions have been drawn. Most research has focused on abiotic environmental factors, but studies on the relationships between A. koreana and soil fungal microbiomes are scarce. In this study, the rhizoplane and rhizosphere fungal communities in the alive and dead Korean fir trees from its three major natural habitats including Mt. Deogyu, Mt. Halla, and Mt. Jiri in Korea were investigated to identify specific soil fungal groups closely associated with A. koreana. Soil fungal diversity in each study site was significantly different from another based on the beta diversity calculations. Heat tree analysis at the genus level showed that Clavulina, Beauveria, and Tomentella were most abundant in the healthy trees probably by forming ectomycorrhizae with Korean fir growth and controlling pests and diseases. However, Calocera, Dacrymyces, Gyoerffyella, Hydnotrya, Microdochium, Hyaloscypha, Mycosymbioces, and Podospora were abundant in the dead trees. Our findings suggested that Clavulina, Beauveria, and Tomentella are the major players that could be considered in future reforestation programs to establish ectomycorrhizal networks and promote growth. These genera may have played a significant role in the survival and growth of A. koreana in its natural habitats. In particular, the genus Gyoerffyella may account for the death of the seedlings. Our work presented exploratory research on the specific fungal taxa associated with the status of A. koreana.

Depopulation is caused by low fertility rates and out-migration, and it applies to countries, regions and smaller areas. Rural depopulation is defined as a sharp population decline that falls well below an adequate population size and indicates that an area has lost its demographic reproductive capacity. This paper discusses the socioeconomic and territorial aspects of rural depopulation, attempting to do justice to the spatial dimensions of the phenomenon. Greece exhibits all the symptoms of demographic transition, leading to labour shortages, declining economic productivity, and increasing demands on the health and welfare system. The study on rural depopulation in Greece focuses on the changes and dynamics observed at the municipal and regional levels. A typology has been developed to identify rural communities in Greece. The main source of demographic data for our study is the Greek censuses (1991, 2001, 2011, and 2021). Demographic and socioeconomic trends in Greece are interlinked and show different regional and local dynamics. Rural depopulation is closely related to the study of (international and internal) migration, even though the latter does not provide a permanent solution to depopulation. An empirical analysis has shown that there is a need to revitalise rural areas through socioeconomic improvements, infrastructure investments, and policies that directly impact rural communities.

This study first examines changes in the amount of residential area on a regional scale, which is said to shrink following population decline, using Japan as an example, where population decline is already underway in most of the country. Second, it examines how the regional governments have set future targets for residential areas and whether these targets are consistent with the current trend. Third, it examines how prefectures, Japan’s regional governments, are responding to this situation through regional land use planning. The methodologies of the paper are a combination of collecting and sorting out the related data, reviewing and extracting information from planning documents, and conducting interviews with persons in charge. In conclusion, residential areas have continued to increase on a regional scale, even as the population has declined. Shrinkage does not follow population decline on a regional scale. It was also found that the amount of residential area changed more closely with the change in households than with the population. National and regional land use plans generally set targets for more shrinkage than the actual trend. The underestimation of the amount of residential area was due to the rapid decline in the number of persons per household. Cases of the three prefectures showed that specific control is left to the individual acts, while the measures are indicated in the wording by the prefectural land use plans.

This study investigated the ethnobotanical uses of Afzelia africana Sm. ex Pers., a threatened tree species in Nigeria to determine the impact of uses of this species on the risk of its extinction. Ethnobotanical surveys were conducted by means of semi-structured questionnaires with the local community called Ijebu Igbo in Ogun state of Nigeria and a total of 60 respondents were interviewed from this community. Herbalists, artisans, Islamic scholars, traders, and retirees were interviewed to document their knowledge of the uses of A. africana. This study revealed that there are different uses of A. africana, among which its spiritual and medicinal uses were the most dominant. An unsustainable harvest of A. africana for these uses will aggravate the decline of its population, thereby increasing the risk of extinction. This study recommends local awareness of the indigenous people of possible ways this species can be utilized in a sustainable manner to prevent its extinction. [ABSTRACT FROM AUTHOR]

Garra cambodgiensis (stonelapping minnow) has experienced significant population declines, prompting intensive research and management, although its distribution in river systems such as the Mekong remains obscure. Effective conservation and management necessitate accurate monitoring and survey data on the distribution of freshwater species. Traditional surveying techniques for fish may be challenging and generate insufficient data on species distribution. This study developed an eDNA‐based method for detecting G. cambodgiensis to address this void. Twenty‐one locations were surveyed. Water samples were collected in triplicate from the river's surface at each site and processed within 48 h in a dedicated laboratory. Primers and probes for G. cambodgiensis were meticulously designed and species‐specificity tested to ensure accurate detection without interference from co‐occurring species in the same geographic range. Each water sample was analysed by qPCR using six technical replicates. The results of qPCR were reported as positive with quantifiable eDNA concentration (copies/mL), below the limit of quantification, or non‐detectable. G. cambodgiensis eDNA was detected in water samples collected from 10 out of 21 sampling sites, with concentrations ranging from 8.5 to 2990.0 copies/mL. Importantly, G. cambodgiensis eDNA was consistently detected in all three replicate water samples at each site where the qPCR experiment yielded positive results. The findings of this study demonstrate the feasibility and effectiveness of incorporating eDNA‐based monitoring or surveys for G. cambodgiensis in the ecologically diverse Mekong River. Monitoring based on eDNA can aid in targeting and informing conservation and management of G. cambodgiensis in its natural habitat. Comprehensive and robust information on species distribution can be obtained via an eDNA‐based survey, which could contribute to more efficient and informed decision‐making processes in fisheries management and conservation efforts. [ABSTRACT FROM AUTHOR]

A rapid decline of Abies koreana has been reported in most of the natural alpine habitats in Korea. It is generally accepted that this phenomenon is due to climate change even though no clear conclusions have been drawn. Most research has focused on abiotic environmental factors, but studies on the relationships between A. koreana and soil fungal microbiomes are scarce. In this study, the rhizoplane and rhizosphere fungal communities in the alive and dead Korean fir trees from its three major natural habitats including Mt. Deogyu, Mt. Halla, and Mt. Jiri in Korea were investigated to identify specific soil fungal groups closely associated with A. koreana. Soil fungal diversity in each study site was significantly different from another based on the beta diversity calculations. Heat tree analysis at the genus level showed that Clavulina, Beauveria, and Tomentella were most abundant in the healthy trees probably by forming ectomycorrhizae with Korean fir growth and controlling pests and diseases. However, Calocera, Dacrymyces, Gyoerffyella, Hydnotrya, Microdochium, Hyaloscypha, Mycosymbioces, and Podospora were abundant in the dead trees. Our findings suggested that Clavulina, Beauveria, and Tomentella are the major players that could be considered in future reforestation programs to establish ectomycorrhizal networks and promote growth. These genera may have played a significant role in the survival and growth of A. koreana in its natural habitats. In particular, the genus Gyoerffyella may account for the death of the seedlings. Our work presented exploratory research on the specific fungal taxa associated with the status of A. koreana. [ABSTRACT FROM AUTHOR]

Measures of the area occupied by overwintering monarchs in México since the mid‐1990s show a decline. Summer surveys of monarchs, however, do not show a similar decline. This discrepancy has led to the proposition that summer monarch numbers are actually stable and that increasing mortality during migration has led to declining overwintering numbers. A competing hypothesis is that this discrepancy is due to a sampling bias in the summer counts and that the summer population has declined because of the eradication of milkweed habitat from crop fields that occurred in the late 1990s through mid‐2000s.We posit that the sampling bias occurred during the period when milkweeds were declining in crop fields and resulted from not sampling in the crop fields.We examined three measures of the size of the population made in the fall during migration and four summer survey measures and compared them to the overwintering measures. Counts of migrating monarchs are not expected to have this sampling bias since migrants come from all habitats, including crop fields.During the period of milkweed eradication, counts of the migrating population were correlated with the size of the overwintering population, whereas summer survey counts were not. After milkweed eradication from crop fields, all population measures were correlated with one another.These results indicate that during the pre‐eradication period, summer counts were not an accurate measure of summer population size. Population trends observed at the overwintering site reflect factors, principally milkweed loss, that affect summer population size. [ABSTRACT FROM AUTHOR]

Identifying genetic conservation units (CUs) in threatened species is critical for the preservation of adaptive capacity and evolutionary potential in the face of climate change. However, delineating CUs in highly mobile species remains a challenge due to high rates of gene flow and genetic signatures of isolation by distance. Even when CUs are delineated in highly mobile species, the CUs often lack key biological information about what populations have the most conservation need to guide management decisions. Here we implement a framework for CU identification in the Canada Warbler (Cardellina canadensis), a migratory bird species of conservation concern, and then integrate demographic modelling and genomic offset to guide conservation decisions. We find that patterns of whole genome genetic variation in this highly mobile species are primarily driven by putative adaptive variation. Identification of CUs across the breeding range revealed that Canada Warblers fall into two evolutionarily significant units (ESU), and three putative adaptive units (AUs) in the South, East, and Northwest. Quantification of genomic offset, a metric of genetic changes necessary to maintain current gene–environment relationships, revealed significant spatial variation in climate vulnerability, with the Northwestern AU being identified as the most vulnerable to future climate change. Alternatively, quantification of past population trends within each AU revealed the steepest population declines have occurred within the Eastern AU. Overall, we illustrate that genomics‐informed CUs provide a strong foundation for identifying current and future regional threats that can be used to inform management strategies for a highly mobile species in a rapidly changing world. [ABSTRACT FROM AUTHOR]

The Diécké Forest is the second largest classified forest in Guinea and is an area of high conservation significance for many species including the western chimpanzee, Pan troglodytes verus. It has attracted several research expeditions focusing on chimpanzee presence and tool use since 1993. These studies also identified several instances of human activities impacting primates and other wildlife. Aside from Bossou, Diécké is the only other locality in Guinea where chimpanzees are known to crack nuts with tools. We visited the Diécké Forest in November 2018 to review the status of chimpanzee presence, nut-cracking activity, and conservation threats. We report our findings along with an up-to-date overview of relevant historical, sociopolitical, environmental, and scientific developments in the vicinity. Our survey took place in the vicinity of Korohouan village where research on chimpanzee nut-cracking had previously been conducted. We found scarce evidence of chimpanzee presence in the area (n = 3) with no recent traces of nut-cracking or other activities. Conversely, we found a high incidence of hunting (6.31/km) within the protected area, with smallscale agriculture and commercial activities predominating forest fragments outside the protected area. The intensification of human activities in Diécké pose a serious threat to one of the largest remaining lowland evergreen forests of West Africa and the endangered species that inhabit it, such as the Western chimpanzee. Our study highlights the need for urgent and concerted conservation action and provides an important case study on the disappearing cultural heritage of a chimpanzee population in a human-impacted habitat. [ABSTRACT FROM AUTHOR]

The Mediterranean Shag Gulosus aristotelis desmarestii is a conservation priority seabird endemic to the Mediterranean and Black Seas that is considered a valuable sentinel of marine ecosystem health. However, knowledge of its population size and dynamics in the Adriatic Sea is limited. Here, the majority of the population breeds in Croatia, with a high proportion of birds migrating northwards to the Gulf of Trieste and Venice Lagoon during the non-breeding period. To bridge this knowledge gap, a first coordinated census was undertaken in 2020 and 2021 in the Adriatic region (Italy, Slovenia and Croatia), which supports 20-33% of the total non-breeding Mediterranean subspecies population. In 2020 a total of 4,993 birds were counted while in 2021 the count was 4,871. Italy hosted the largest number of birds (x̄ = 3,040), followed by Croatia (x̄ = 951) and Slovenia (x̄ = 941), with most of the birds (c. 69%) roosting on mussel farms. To fully comprehend the non-breeding population dynamics, we conducted an estimation of the 13-year (2010-2022) population trend in the Gulf of Trieste. During this period, the population strongly declined (–44.7%) for reasons yet to be identified. In 2012-2014, a population fluctuation coincided with an exceptionally wet winter and spring at the Croatian breeding colonies. It is possible that changes in migration strategy, such as new migratory routes, by this partial migrant may have partially offset the decline of birds in the Gulf of Trieste, as the Venice Lagoon population increased during the same period. Overall, the Adriatic population appears to be declining and yet subject to dynamic changes in its non-breeding distribution. To fully comprehend the reasons behind this trend, further research of both breeding and non-breeding populations is necessary. —Scridel, D., Utmar, P., Koce, U., Kralj, J., Baccetti, N., Candotto, S., Ciriaco, S., De Luca, M., Pascucci, M., Sartori, A., Tinarelli, R., Sava, S., Vicario, G. & Spoto, M. (2024). Conservation status of the Mediterranean Shag Gulosus aristotelis desmarestii in the Adriatic Sea during the non-breeding period: baseline population, trends, threats and knowledge gaps. Ardeola, 71: 19-42. El cormorán moñudo mediterráneo Gulosus aristotelis desmarestii es una especie prioritaria de conservación, endémica del mar Mediterráneo y el Mar Negro, y se considera un valioso centinela de la salud del ecosistema marino. Sin embargo, el conocimiento sobre el tamaño y la dinámica de la población de G. a. desmarestii en el Mar Adriático es limitado. Aquí, la mayoría de la población se reproduce en Croacia, con una alta proporción de aves que migran hacia el norte hasta el golfo de Trieste y la laguna de Venecia durante el período no reproductivo. Para cerrar esta brecha de conocimiento, se realizó un primer censo coordinado en 2020 y 2021 en la región del Adriático (Italia, Eslovenia y Croacia), que alberga del 20% al 33% de la población total de la subespecie mediterránea en el período no reproductivo. En 2020 se contabilizaron un total de 4.993 aves, mientras que en 2021 la cifra fue de 4.871. Italia albergó el mayor número de aves (x̄ = 3,040), seguida de Croacia (x̄ = 951) y Eslovenia (x̄ = 941), y la mayoría de las aves (aproximadamente el 69%) se posaron en granjas de mejillones. Para comprender completamente la dinámica de la población en el período no reproductivo, se realizó una estimación de la tendencia de la población en el golfo de Trieste durante 13 años (2010-2022). Durante este período, la población ha experimentado un fuerte declive (–44.7%) por razones aún por identificar. En 2012-2014, se observó una fluctuación temporal de la población coincidiendo con un invierno y primavera excepcionalmente húmedos en las colonias de reproducción croatas. Además, es posible que los cambios en la estrategia de migración (es decir, nuevas rutas migratorias) de esta especie parcialmente migratoria hayan contrarrestado la disminución de las aves en el golfo de Trieste, ya que hubo un aumento de la población en la laguna de Venecia durante el mismo período. En general, la población del Adriático parece estar disminuyendo y su distribución en el período no reproductivo está sujeta a cambios dinámicos. Para comprender completamente las razones detrás de esta tendencia, se necesitan investigaciones adicionales sobre la población en período reproductivo y no reproductivo.—Scridel, D., Utmar, P., Koce, U., Kralj, J., Baccetti, N., Candotto, S., Ciriaco, S., De Luca, M., Pascucci, M., Sartori, A., Tinarelli, R., Sava, S., Vicario, G. y Spoto, M. (2024). Estado de conservación del cormorán moñudo mediterráneo Gulosus aristotelis desmarestii en el mar Adriático durante el período no reproductivo: población de referencia, tendencias, amenazas y lagunas de conocimiento. Ardeola, 71: 19-42. [ABSTRACT FROM AUTHOR]

Breeding habitat loss and depletion of genetic diversity can have critically negative impacts on species, and especially so for habitat specialists. The Aquatic Warbler Acrocephalus paludicola is a threatened European songbird that breeds in fens, which have been lost and fragmented over centuries. We used microsatellite loci to perform a spatial and longitudinal comparison, comparing samples collected recently (contemporary) with those obtained about two decades earlier (historical) from c. 25% of the breeding range (Biebrza and Polesie) of the Aquatic Warbler. With these data we explored changes in genetic diversity, expansions and reductions of population size, population structure, and gene flow. Allelic richness, expected heterozygosity, the number of effective and private alleles, and effective population size (NE ≈ 200) were low and comparable across time and space. We detected a genetic bottleneck in contemporary Biebrza, and a less certain bottleneck in both historical and contemporary Polesie. Across space, Biebrza and Polesie were not genetically differentiated in either period. All the historical samples clustered together, but in the contemporary samples a small part of Polesie clustered separately (FST = 0.011). Across time, Biebrza and Polesie showed low but significant differentiation (FST = 0.026–0.064), and historical and contemporary groups clustered apart. A principal coordinate analysis on genetic distance detected three groups, which spanned sampling locations. In the temporal comparison, the contemporary group and contemporary Biebrza had elevated mean within‐group pairwise relatedness. We did not recover signals for sex‐biased dispersal, asymmetric gene flow or isolation‐by‐distance using the molecular data. Our results suggest that the studied populations show: (1) impoverished genetic diversity, (2) a change in allele frequencies over the two decades studied and (3) high gene flow between distant breeding sites, implying high resilience to habitat fragmentation that should facilitate the success of recolonising restored habitat patches by Aquatic Warblers. [ABSTRACT FROM AUTHOR]

Context. Over the past few decades, many mammalian species have experienced range shifts, due to either local extinction or expansion, under accelerating global climate change. However, the distinct effects and ecological mechanisms behind the anthropogenic and climate pressures on range shifts have not been fully studied. Aims. Our aim was to examine the impacts of climate warming and human disturbance on the local disappearance probability and northwards range contraction at the southern distribution boundary of the greater long-tailed hamster (Tscherskia triton), a rodent pest, in northern China. The assessment was based on historical records from 1963 to 2018. Methods. Logistic generalised additive models were used to quantify the association between local disappearance probability and environmental variables in the greater long-tailed hamsters. The air temperature threshold for local disappearance of the greater longtailed hamsters (defined as the disappearance threshold) was estimated using the year following the last observation year. We also predicted changes in the distribution of the greater longtailed hamsters under future warming scenarios. Key results. The greater long-tailed hamster population has experienced notable population decline and range contraction along its southern boundary during the past 48 years. The probability of local disappearance is closely associated with climate warming (indexed by the annual air temperature), drought (indexed by annual precipitation), and human disturbance (indexed by the population density). The threshold of the yearly maximum temperature for local disappearance was 15.8 ± 3.87°C, and the average maximum temperature of the warmest months (from June to August) was 28.21 ± 2.71°C. Our projection model indicates that ongoing climate warming will cause more range contraction of the plain areas at the southern boundary of the greater long-tailed hamster distribution. Conclusions. Over recent decades, rapid climate change and human disturbance have been associated with population decline and northwards range contraction of the southern boundary for the greater long-tailed hamster population in China. Implications. Our study has significant implications for managing the damage done to farmland crops by this species, as well as the future conservation of this species in natural ecosystems. [ABSTRACT FROM AUTHOR]

In contrast to the overpopulation predicted by the population explosion theory in the 1960s, the issue of depopulation has attracted increasing attention from governments and scholars around the world. To explore the driving factors that have affected the birth rate in China, we obtained data on the birth rates in 31 Chinese provinces from 1990 to 2019. We then conducted feasible generalized least-squares regression analysis to identify the key factors. The results show that marketization, education level, and the proportions of secondary and tertiary industries were the key factors contributing to the decreasing birth rate, whereas improvements of transportation and medical services supported the desire to have children. Although the degree of influence of different factors differed over time and across regions, the economic and educational factors remained important and should not be underestimated. We propose that if the government wants to increase the willingness of young men and women to have children and help China to maintain a sustainable population, it should reduce the economic and opportunity costs of childbearing and the burden of raising children. Our methodology and outcomes will provide a reference for other countries that must identify key driving factors to support the development of their own population policies. [ABSTRACT FROM AUTHOR]

We report a recent record of the elusive Eurasian Otter Lutra lutra from Kerala, through a direct observation in the higher reaches of the Chinnar Wildlife Sanctuary within the Western Ghats, southern India. Field observation involved the sighting of two Eurasian Otters in a rocky-torrential stream in March 2020. The otters displayed a hyperactive foraging behaviour, searching among submerged rocks and crevices, followed by occasional dives. They seemed particularly interested in areas where water rushed with force, avoiding locations with low water flow or shallow pools. The observation site, at 1,275 m altitude in Chinnar Wildlife Sanctuary, located in the Western Ghats of Kerala region, featured wet evergreen vegetation, transitional sholas (stunted evergreen forests), and riparian patches along a stream characterised by rapid water flow, boulders, and fallen trees. This habitat, as observed by others, was also indicative of Asian Small-clawed Otter Aonyx cinereus suitability, suggesting potential resource partitioning between the two otter species. This discovery challenges previous assumptions about the preferred habitat of Eurasian Otters in the Western Ghats and emphasizes the need for comprehensive research on the taxonomy, distribution, population status, and behaviour of these possibly sympatric species of otters, the Asian Small-clawed Otter and the Eurasian Otter. Such studies are crucial for the conservation of both these species, which face threats from habitat loss, sand mining, hunting, and population decline. Preserving and restoring riparian vegetation in the higher reaches of the Western Ghats is essential for their protection within this biodiversity hotspot. [ABSTRACT FROM AUTHOR]

The extent of shrinkage in the Netherlands is rather limited so far. Still, the Netherlands was one of the first European countries that introduced a national-level policy for regions facing structural population decline and shrinkage in 2009: the Population Decline Action Plan. This happened in response to local and regional policy initiatives and a lobby of local and regional governments, but also because the Minister of the Interior perceived shrinkage as a national policy challenge. This action plan was an attempt to arrange a multiscalar governance of shrinkage at national, regional, and local scales. However, this policy ended in 2019, and its last remaining element, a targeted subsidy for regions facing structural population decline, ended in 2022. This article will discuss (a) how and why the policy was introduced and how its governance was arranged, (b) how the policy changed between 2009 and 2022, (c) why it ended, (d) which new regional policies have been developed recently instead, and (e) what this could mean for the governance of shrinkage in the Netherlands.

The saiga antelope (Saiga tatarica tatarica L., 1766, S) is a prominent ungulate mammal species inhabiting Central Asia. Over the latter half of the 20th century, saiga populations, including the Volga-Ural (Kazakhstan) population, experienced a continuous decline. However, there was a resurgence in their numbers in the 1980s. This study aims to assess the present status of saiga populations, particularly the Volga-Ural (V-U) population, by analyzing existing retrospective data. Our findings reveal that during the 21st century, the saiga population has increased in two key regions: the Volga-Ural and Betpak-Dala (B) populations. Notably, the Northern-Western Population (NWP) habitat saw a drastic 50-fold decline in population, while other populations decreased by 2.0-5.0 times. Despite this decline, the NWP habitat exhibited higher juvenile saiga yields compared to other regions. The resurgence of saiga populations has been significantly influenced by the support of the Government of Kazakhstan, along with the effective efforts of international wildlife conservation organizations and local community engagement.