Continued Population Decline Research Articles

A sacrifice for the greater good? On the main drivers of excessive land take and land use change in Hungary

Despite continuous population decline or stagnation, many Central and Eastern European cities experience urban sprawl and expansion, accompanied by excessive land take and land use change. This paper investigates recent trends in land take and land use change in Hungarian cities, aiming to identify the drivers of these processes. The study utilizes the Urban Atlas (UA) databases from 2006 and 2018 to analyze land use change in selected Hungarian cities, employing QGIS software to compile the database and MS Excel to conduct the statistical analysis. A linear trajectory model is employed to project land use change by 2026, based on 2006–2018 UA data. Additionally, via the in-depth analysis of Debrecen, the study highlights the recent acceleration of land use change to compare the projected trend with the forecasted one. Local climate strategies focus on addressing environmental concerns, including changes in land use at the city level. Therefore, this study reviews the relevant documents associated with each city to assess its commitment to reducing land take. The results indicate that despite its declining population, Hungary has seen a significant expansion in artificial surfaces, primarily due to industrialization and population policies introduced by the central government, which is likely to continue in the coming years. Unfortunately, local climate strategies have been insufficient in preventing cities from experiencing urban sprawl and expansion and preserving local ecosystem services. This underscores the inability of municipalities to defend local interests against central government directives. The findings of this study indicate that the current central policies are the main drivers of land take and urban sprawl and expansion. Prioritizing the compact city model and brownfield developments could effectively mitigate these issues. Finally, the paper advocates that complete jurisdiction over land use decisions be restored to local governments, enabling them to reject investments that may jeopardize local environmental goals.

Novel insight into the genetic diversity of strongylid nematodes infecting South-East and East Asian primates.

With many non-human primates (NHPs) showing continued population decline, there is an ongoing need to better understand their ecology and conservation threats. One such threat is the risk of disease, with various bacterial, viral and parasitic infections previously reported to have damaging consequences for NHP hosts. Strongylid nematodes are one of the most commonly reported parasitic infections in NHPs. Current knowledge of NHP strongylid infections is restricted by their typical occurrence as mixed infections of multiple genera, which are indistinguishable through traditional microscopic approaches. Here, modern metagenomics approaches were applied for insight into the genetic diversity of strongylid infections in South-East and East Asian NHPs. We hypothesized that strongylid nematodes occur in mixed communities of multiple taxa, dominated by Oesophagostomum, matching previous findings using single-specimen genetics. Utilizing the Illumina MiSeq platform, ITS-2 strongylid metabarcoding was applied to 90 samples from various wild NHPs occurring in Malaysian Borneo and Japan. A clear dominance of Oesophagostomum aculeatum was found, with almost all sequences assigned to this species. This study suggests that strongylid communities of Asian NHPs may be less species-rich than those in African NHPs, where multi-genera communities are reported. Such knowledge contributes baseline data, assisting with ongoing monitoring of health threats to NHPs.

지방소멸대응기금 성과분석에 따른 개선 방향 고찰

Two years have passed since the local extension reaction Fund was introduced and the budget was allocated to overcome the problem of continuous population decline. The government expects that the annual budget of 1 trillion won, focusing on 89 population-decreasing areas, will alleviate the serious population decline problem, especially in non-capital areas. Therefore, this study analyzed based on statistical data on the extent to which the fund performed in the population-decreasing area. As a result of the analysis, it was confirmed that the population decline in the population-decreasing area was significantly alleviated and the net outflow of young people decreased in size compared to before the input of the fund. Nevertheless, it was also confirmed that there is a limit to responding to the population decline in South Korea with this fund, considering the fact that the population has turned to a decline in areas that are not designated as a population-decreasing area or the scale of net outflow of young people has expanded. In the end, in order to overcome the problem of rapid population decline in South Korea, there are certain limitations in establishing investment plans and discovering projects at the level of basic local governments, so it would be desirable to approach it through regional planning and project discovery based on inter-regional cooperation. In addition, in terms of the financial system, it is necessary to overcome the population crisis by efficient financial input to enable the linkage of this fund project with the Special Account for Balanced National Development or other budget projects.

Genome sequences and population genomics provide insights into the demographic history, inbreeding, and mutation load of two 'living fossil' tree species of Dipteronia.

'Living fossils', that is, ancient lineages of low taxonomic diversity, represent an exceptional evolutionary heritage, yet we know little about how demographic history and deleterious mutation load have affected their long-term survival and extinction risk. We performed whole-genome sequencing and population genomic analyses on Dipteronia sinensis and D. dyeriana, two East Asian Tertiary relict trees. We found large-scale genome reorganizations and identified species-specific genes under positive selection that are likely involved in adaptation. Our demographic analyses suggest that the wider-ranged D. sinensis repeatedly recovered from population bottlenecks over late Tertiary/Quaternary periods of adverse climate conditions, while the population size of the narrow-ranged D. dyeriana steadily decreased since the late Miocene, especially after the Last Glacial Maximum (LGM). We conclude that the efficient purging of deleterious mutations in D. sinensis facilitated its survival and repeated demographic recovery. By contrast, in D. dyeriana, increased genetic drift and reduced selection efficacy, due to recent severe population bottlenecks and a likely preponderance of vegetative propagation, resulted in fixation of strongly deleterious mutations, reduced fitness, and continuous population decline, with likely detrimental consequences for the species' future viability and adaptive potential. Overall, our findings highlight the significant impact of demographic history on levels of accumulation and purging of putatively deleterious mutations that likely determine the long-term survival and extinction risk of Tertiary relict trees.

Conservation genetics of endangered Trillium govanianum Wall. ex D. Don – A pharmaceutically prized medicinal plant from the Himalaya and implications for species recovery

Understanding the genetic diversity and population structure of pharmaceutically important endangered plant species is crucial for their conservation and sustainable use. Despite the continuous population decline in Trillium govanianum Wall. ex D. Don, a highly prized medicinal plant endemic to the Himalaya, information regarding its conservation genetics has been lacking. Here, we employed a conservation genetics approach to investigate how drastically declining populations in natural habitats impact population genetic diversity and structure of this endangered species across the Kashmir Himalaya. We used Start codon targeted (SCoT) and Simple sequence repeat (SSR) markers to assess the intra- and inter-population genetic variation in seven sites across the study region. Based on these markers, we found a very low genetic diversity in T. govanianum populations. Very low levels of observed heterozygosity (Ho = 0.000) and that expected (He = 0.064) in the populations indicate high heterozygote deficiency and high levels of inbreeding depression (FIS = 1.000). A high genetic differentiation was observed among the populations for both SCoT (Gst = 0.719) and SSR (Fst = 0.707) markers. Both the markers showed low gene flow, SCoT (Nm = 0.195) and SSR (Nm = 0.119), depicting high among-population variation than within-population variation. Analysis of molecular variance also indicated a higher genetic variation between the populations than within populations. We also observed a significant positive correlation between genetic divergence and geographical distance, indicating that genetic differentiation in T. govanianum follows a pattern of isolation by distance. Bayesian structure and cluster analysis grouped the populations according to their geographical proximity. Further, redundancy analysis (RDA) revealed the presence of one polymorphic locus for each marker with high discriminatory power. Overall, our findings reveal a very low genetic diversity, high levels of inbreeding, and high genetic differentiation among the populations; likely resulting from habitat fragmentation, population isolation, bottleneck effect, low gene flow, and predominantly asexual reproduction currently operative in the species. Finally, based on the insights gained, we discuss the potential implications of our findings in guiding species recovery and habitat rehabilitation of T. govanianum in the Himalaya with conservation lessons for elsewhere in the world.

The mitochondrial genome of the endemic and endangered trumpet-nosed bat Musonycteris harrisoni (Chiroptera: Phyllostomidae)

ABSTRACT The trumpet-nosed bat Musonycteris harrisoni (family Phyllostomidae) is endemic to the western Pacific slope of Mexico, and is considered endangered given prolonged and continuous population decline. This study, for the first time, assembled and characterised in detail the mitochondrial genome of this species that is in need of genomic resources. The mitogenome of Musonycteris harrisoni is 16,668 bp in length and encodes 13 protein-coding genes (PCGs), 22 transfer RNA genes (tRNAs), two ribosomal RNA genes (rRNAs), and a relatively long non-coding putative control region (CR) 1229 bp in length. Mitochondrial synteny is identical to that reported before in the family Phyllostomidae. As reported before in all phyllostomids, most mitochondrial genes are encoded on the heavy strand (H-strand), except for nad6 and eight tRNA genes that are encoded on the light strand (L-strand). All the tRNAs exhibit a ‘cloverleaf’ secondary structure, except tRNA Serine-1 that is missing the dihydrouridine (DHU) arm. All 13 mitochondrial PCGs are evolving under purifying selection, with atp8, nad4l and nad6 experiencing relaxed purifying selection in comparison to the other PCGs. Tandem repeats, microsatellites, and hairpin structures are observed in the CR of Musonycteris harrisoni, in agreement with what has been reported before in other cofamilial bats. The CR contains three functional domains: extended termination associated sequence (ETAS) domain, central domain, and conserved sequence block (CSB) domain. The mitochondrial genome sequence herein characterised completely and in detail represents a new genomic resource for M. harrisoni that will further the understanding of genetic diversity in this endangered species.

Computer-assisted semen analysis in large falcons (Falco spp.) and comparison to results of conventional semen analysis

Numerous raptor species including some falcon species are facing continuous population decline in the wild and some are threatened by extinction. To support these species, captive breeding and reintroduction programs are attempted. Besides conservation, some large falcon species are commonly used in falconry and therefore bred commercially. Assisted reproduction is established in falcon breeding since the 1970s and semen analysis is an integral part to enable assessment of breeding males, inclusion or exclusion of semen donors and quality control of semen prior to artificial insemination. Conventional methods for semen analysis are widely used, but are time consuming and depend on the investigator's experience and ability. Computer-assisted semen analysis (CASA) would offer an objective, fast and reproducible alternative, but as they have not been established in large falcon species, this was the aim of this study. To this end, we examined in 3 breeding seasons 109 semen samples of gyr-saker hybrid falcons (n=2) and peregrine falcons (n=4) in 940 fields of view using the Minitube CASA SpermVision and compared these results to results of conventional methods of semen analysis. We used a preprogrammed setting and adapted two settings of CASA according to specific semen characteristics of falcons. Sperm velocity, motility and viability parameters were recorded successfully using CASA. Correlation of conventional and computer-assisted motility analysis improved during the process of adaptation of CASA settings, but both methods differed significantly due to misinterpretation of round bodies and semen impurities by CASA. Viability values of conventional and computer assisted viability analysis using SYBR-PI correlated significantly while sperm concentration did not at all. CASA failed to replace conventional semen analysis regarding sperm motility and sperm concentration using 3 different settings, as a reliable differentiation between spermatozoa, spermatids and round bodies was not achieved. Using CASA, sperm velocity parameters were measured in spermatozoa of captive-bred large falcons for the first time and may be used as orientation values.

Using passive acoustic monitoring to estimate northern spotted owl landscape use and pair occupancy

AbstractManaging forests for biodiversity conservation while maintaining economic output is a major challenge globally and requires accurate and timely monitoring of imperiled species. In the Pacific Northwest, USA, forest management is heavily influenced by the status of northern spotted owls (Strix occidentalis caurina), which have been in continued population decline for the past four decades. The monitoring program for northern spotted owls is transitioning from mark–resight surveys to a passive acoustic framework, requiring development of alternative analysis approaches. To maintain relevance for conservation and management, these analyses must accurately track underlying population changes, identify responses to disturbance, and estimate occupancy of owl pairs. We randomly selected and surveyed 5‐km2 hexagons for 6 weeks using passive acoustic monitoring in the Olympic Peninsula of Washington and the Oregon Coast Range during the 2018 spotted owl breeding season. We used a convolutional neural network to identify spotted owl calls, followed by logistic regression to determine the sex of vocalizing owls to assign pair status. We implemented multistate occupancy models to estimate probabilities of detection, species‐level landscape use, and pair occupancy of spotted owls. We also quantified detections of barred owls (Strix varia), a congeneric competitor and important driver of spotted owl population declines. The overall rate of hexagon use by spotted owls was estimated at 0.21 (SD 0.04) after adjusting for imperfect detection, and pair occupancy was 0.07 (SD 0.02). The probability of detecting a pair (i.e., both female and male) during a weekly occasion was relatively low (0.03, SD 0.01), indicating that true pair occupancy was between 1.3 and 4.1 times greater than the proportion of hexagons with observed pair detections. Barred owls were ubiquitous, with a naïve occupancy rate of 0.97. The intensity of calling by barred owls had a weak, negative effect on the probability of spotted owls being paired when present but had little measurable effect on their detectability. This work establishes a framework that may be effective for spotted owl population monitoring and illustrates that pairs have very low detection probability, which—combined with increasingly low numbers of spotted owl pairs—is an important consideration for conservation and management.

Addressing Peripherality in Italy: A Critical Comparison between Inner Areas and Territorial Capital-Based Evaluations

As highlighted by the UN 2030 Agenda, sustainable development is a complex and multidimensional issue that can be effectively implemented and reached at the local level. This implies the evaluation of differences and disparities between territories in order to define local priorities and support cohesion policy objectives. This need has been addressed by the Italian “National Strategy for Inner Areas”, which aims to support the growth of territories with a continuous economic and population decline. However, Inner Areas are identified by a set of indicators related to the low accessibility to Services of General Interest, neglecting other important factors that contribute to this condition. This paper proposes a critical analysis of this measurement and of the related “territorialization” of Inner Areas, by introducing a more comprehensive assessment model based on the concept of Territorial Capital (TC), which highlights a more nuanced understanding of complexities and diversities related to the potential development of a territory. In particular, the proposed model evaluates eight TC dimensions (human, social, cognitive, infrastructural, productive, relational, environmental and settlement capital), which cover a broad spectrum of Sustainable Development Goals (SDGs). In order to accurately demonstrate the differences between the results of the two evaluation methods, this paper presents the results of a case study application concerning all 377 municipalities, which compose the Autonomous Region of Sardinia (Italy). The findings of this study confirm the potential of an approach based on the Territorial Capital for place-based policymaking. TC, in fact, can become relevant for defining local priorities and supporting complex decisions, allowing governments to better design and tailor interventions for the effective and efficient management of available resources. Furthermore, these results pose new questions for future research developments in the field of sustainable and equitable development.

Effect of Manila clam Ruditapes philippinarum on burial depth of eelgrass Zostera marina seeds and sediment porosity

Eelgrass Zostera marina is widely distributed in coastal areas of the Northern Hemisphere; however, its continuous population decline is increasingly serious. Besides exogenous stresses, there are endopathic reasons for the decline, e.g., its seedling establishment rate, which is affected by burial depth of seeds and sediment types, is extremely low. Studies have shown that eelgrass seedlings in bivalve distribution areas are easier to establish. Moreover, large-scale bottom sowing culture for bivalves affects the bulk density of sediments which affects seed germination and seedling establishment of eelgrass. This study sought to examine the relationship between sediment modification induced by Manila clams with different body size and stocking density and the burial depth of eelgrass seeds caused by clams. The porosity of surface sediments varied with Manila clam biomass and was mainly affected by clam body size. Clams with a weight of 2.56 ± 0.12 g created more porosity. Clams with a weight of 3.71 ± 0.10 g caused more porosity than clam with a weight of 7.47 ± 0.22 g did. The sand diving of Manila clams affected the distribution of eelgrass seeds in sediments at different depths. The moderately abundant and large Manila clams promoted the burial depth of eelgrass seeds in sediments, and this effect was more obvious at 1–3 cm near the burial depth of 2 cm which is conducive to germination of eelgrass seeds and seedlings establishment. Thus, based on the bioturbation of Manila clams, the efficiency of sowing methods to restore the eelgrass population can potentially be improved.

Induced pluripotent stem cells and cerebral organoids from the critically endangered Sumatran rhinoceros

Less than 80 Sumatran rhinos (SR, Dicerorhinus sumatrensis) are left on earth. Habitat loss and limited breeding possibilities are the greatest threats to the species and lead to a continuous population decline. To stop the erosion of genetic diversity, reintroduction of genetic material is indispensable. However, as the propagation rate of captive breeding is far too low, innovative technologies have to be developed. Induced pluripotent stem cells (iPSCs) are a powerful tool to fight extinction. They give rise to each cell within the body including gametes and provide a unique modality to preserve genetic material across time. Additionally, they enable studying species-specific developmental processes. Here, we generate iPSCs from the last male Malaysian SR Kertam, who died in2019, and characterize them comprehensively. Differentiation in cells of thethree germ layers and cerebral organoids demonstrate their high quality and great potential for supporting the rescue of this critically endangered species.

Empirical Examinations of Whether Rural Population Decline Improves the Rural Eco-Environmental Quality in a Chinese Context

Rural population has continually declined in response to the rapid urbanization process occurring in China, and the related negative socioeconomic impacts on rural development have attracted considerable attention from scholars. Currently, few studies have investigated the eco-environmental impact of rural population decline. By employing remote-sensing data, including land-use and normalized difference vegetation index (NDVI) data, this study proposed a method based on the eco-environmental quality index (EQI) to measure the changes in the rural eco-environmental quality (REQ) at the prefectural level from 2000 to 2020. Then, we examined the impacts of rural population decline on REQ variations. We found that (1) most of the research units experienced continuous rural population decline during the research period, with the rural population density declining more than 25% from 2010 to 2020 in approximately half of the research units; (2) the REQ improved in most of the units, especially in the western region, but there were still many units that experienced a decline in the REQ, which were primarily concentrated in the coastal and central regions; (3) rural population decline improved the REQ, but its impacts varied regionally; and (4) rural population density, natural factors, and eco-environmental protection programs had significant influences on REQ variations. These findings may provide a reference for sustainable-development policies in rural China and other developing countries.

African wild dogs (Lycaon pictus) from the Kruger National Park, South Africa are currently not inbred but have low genomic diversity

African wild dogs (Lycaon pictus) have undergone severe population reductions and are listed as endangered on the International Union for Conservation of Nature Red List. Small, isolated populations have the potential to suffer from threats to their genetic diversity that may impact species viability and future survival. This study provides the first set of population-wide genomic data to address conservation concerns for this endangered species. Whole genome sequencing data were generated for 71 free-ranging African wild dogs from the Kruger National Park (KNP), South Africa, and used to estimate important population genomic parameters. Genomic diversity metrics revealed that variation levels were low; however, this African wild dog population showed low levels of inbreeding. Very few first- and second-order relationships were observed in this cohort, with most relationships falling into the third-order or distant category. Patterns of homozygosity could have resulted from historical inbreeding or a loss in genome variation due to a population bottleneck. Although the results suggest that this stronghold African wild dog population maintains low levels of inbreeding, likely due to their cooperative breeding system, it may lead to a continuous population decline when a reduced number of suitable mates are available. Consequently, the low genomic variation may influence species viability over time. This study highlights the importance of assessing population genomic parameters to set conservation priorities. Future studies should include the investigation of the potential of this endangered species to adapt to environmental changes considering the low genomic diversity in this population.

Gastrointestinal symbiont diversity in wild gorilla: A comparison of bacterial and strongylid communities across multiple localities

Western lowland gorillas (Gorilla gorilla gorilla) are Critically Endangered and show continued population decline. Consequently, pressure is mounting to better understand their conservation threats and ecology. Gastrointestinal symbionts, such as bacterial and eukaryotic communities, are believed to play vital roles in the physiological landscape of the host. Gorillas host a broad spectrum of eucaryotes, so called parasites, with strongylid nematodes being particularly prevalent. While these communities are partially consistent, they are also shaped by various ecological factors, such as diet or habitat type. To investigate gastrointestinal symbionts of wild western lowland gorillas, we analysed 215 faecal samples from individuals in five distinct localities across the Congo Basin, using high-throughput sequencing techniques. We describe the gut bacterial microbiome and genetic diversity of strongylid communities, including strain-level identification of amplicon sequence variants (ASVs). We identified strongylid ASVs from eight genera and bacterial ASVs from 20 phyla. We compared these communities across localities, with reference to varying environmental factors among populations, finding differences in alpha diversity and community compositions of both gastrointestinal components. Moreover, we also investigated covariation between strongylid nematodes and the bacterial microbiome, finding correlations between strongylid taxa and Prevotellaceae and Rikenellaceae ASVs that were consistent across multiple localities. Our research highlights the complexity of the bacterial microbiome and strongylid communities in several gorilla populations and emphasizes potential interactions between these two symbiont communities. This study provides a framework for ongoing research into strongylid nematode diversity, and their interactions with the bacterial microbiome, among great apes.

Promotion of Child Health and Development Care in Pharmacy Education

Japan is simultaneously facing both an aging society and low birth rates, causing a continuing population decline. To cope with the declining birthrate, it is urgent to make child health and development medicine a natural accompaniment to all life stages. As pharmacists and pharmacies have a major role to play in this, it is necessary to position child health and development medicine in training for student pharmacists. On the other hand, student pharmacists are young adults who may be directly involved in child health and development, and this is not only an issue for women, but also needs to be understood by men. This symposium provides an opportunity to build a consensus on the role of pharmacists in the increasingly diverse and sophisticated support for child development in terms of pharmaceutical education.

Long-term increase in mortality of Indo-Pacific humpback dolphins (Sousa chinensis) in the Pearl River Estuary following anthropic activities: Evidence from the stranded dolphin mortality analysis from 2003 to 2017

With the dramatic increase in anthropogenic threats to the Pearl River Estuary (PRE), the population size of the Indo-Pacific humpback dolphins (Sousa chinensis) has significantly decreased over the past decade. To understand the impact and potential risks of intense human activities on these dolphins, factors related to the mortality of humpback dolphins in the PRE were investigated by a detailed examination of 343 dolphin specimens stranded during 2003–2017. There was a significant (p < 0.01) increasing trend for humpback dolphin stranding, reflecting the accelerating rate of the population decline. A large proportion of strandings (35.88%) were neonates. A low recruitment rate implies slow population growth, and hence, limited capacity to resist anthropogenic stress. The most commonly diagnosed causes of death were vessel collision and net entanglement. The concentrations of trace metals, polychlorinated biphenyl (PCB) congeners, dichlorodiphenyltrichloroethane, polycyclic aromatic hydrocarbons, and most of per- and polyfluoroalkyl substances (PFASs) in the dolphin samples were greater than those previously reported in cetaceans globally. Furthermore, Cu, PCB77, PCB169, PCB81, PCB37, and PFASs (excluding PFBA, PFPeA, PFHxA, PFHxDA, and PFODA) were the major pollutants accumulated in neonates. 67% of PCB, 78% of Cu, and 100% of perfluorooctane sulfonate concentrations in the neonates exceeded the threshold for toxicological effects in marine mammals, suggesting that these compounds could be important factors contributing to the low survival rate of calves in this area. This study revealed that vessel transportation, fishing activities, and pollutant bioaccumulation are the three major causes of humpback dolphin mortality in the PRE. These results highlight the need for more efforts to restrict anthropogenic activities, especially vessel traffic, the catching of these marine animals and fishing, and pollutant discharge, in order to prevent vulnerable species from continuous population decline and further extinction.

Dynamic simulations of compact city development to counter future population decline

The study simulated the impact of compact city policies on urban services and urban finances by employing a dynamic and spatial land use/transport model. The Metropolitan Activity Relocation Simulator (MARS) was selected as the dynamic and spatial land use/transport model to analyze dynamic urban aggregation changes over time. However, it was not possible to simulate the compact city policies under population decline using the existing MARS. Thus, to dynamically simulate the compact city policies, the MARS was adapted by adding two additional sub-models focused on urban service levels and urban finances. The urban service levels and urban finances were then analyzed during the aggregation process to simulate the policies for a compact city with a declining population. Subsequently, the urban service levels and urban finances were analyzed during the consolidation by simulating the policies for a compact city with a declining population. The findings showed that the disparities in urban areas and suburban public service levels widened, and the local government costs increased by implementing the policy. It was, therefore, concluded that the development of a compact city might be a relief to this situation under continuing population decline, and the implementation of subsidy and preferential treatment policies are greatly required to move residents to urban areas and encourage the compact city.

Dysbiosis in the Rhizosphere Microbiome of Standing Dead Korean Fir (Abies koreana).

The Korean fir (Abies koreana), a native coniferous tree species mainly found on Mt. Halla in Jeju, South Korea, is suffering from continuous population decline and has been declared an endangered species. Research efforts have focused on the possible abiotic causes behind this worrying decline. However, the potential link between tree vitality and the rhizosphere microbiome remains unclear. In this study, a comparative metagenomic 16S rRNA sequence analysis was used to investigate the composition of the rhizosphere microbiota of samples collected from healthy and die-back-affected trees on Mt. Halla. The results indicated a significant reduction in the richness and diversity of microbiota in the rhizosphere of die-back-affected trees. Moreover, the relative abundance of Proteobacteria, Actinobacteria, and Bacteroidetes were significantly higher in healthy trees than in standing dead trees. Many bacterial genera were significantly more abundant in the rhizosphere of healthy trees, including those known for promoting plant growth and tolerance to biotic and abiotic stresses (e.g., Bradyrhizobium, Rhizomicrobium, Caulobacter, Nitrosospira, Rhizobacter, Paraburkholderia, Rhizobium, Devosia, Caballeronia, Niveispirillum, Dyella, Herbaspirillum, Frankia, Streptomyces, Actinoallomurus, Lysobacter, Luteibacter, Mucilaginibacter, and Variovorax). To our knowledge, this is the first report on rhizosphere bacterial microbiome dysbiosis in die-back-affected Korean fir trees, suggesting that the influence of rhizosphere microbiota should be considered to save this endangered species by investigating possible intervention strategies in future work.

Acute and lagged fitness consequences for a sagebrush obligate in a post mega-wildfire landscape.

Species responses to disturbance influence their extinction risks. Greater sage‐grouse (Centrocercus urophasianus) are bioindicators of sagebrush ecosystem health and the loss of sagebrush (Artemisia spp.) due to wildfire, can cause long‐term declines in sage‐grouse populations and other sagebrush obligate species. We examined the demographic response of a greater sage‐grouse population following a mega‐wildfire using stochastic age‐structured female‐based matrix models over 6 years (2013–2018). Notably, chick survival (range = 0.18–0.38) and female survival (yearling range: 0.20–0.68; adult range: 0.27–0.75) were low compared to values reported for greater sage‐grouse in other parts of their distribution. Greater sage‐grouse displayed variation in demographic tactics after the fire; however, adult female survival explained most of the variation in λ during each year, which reflected a declining population in 3 of 6 years with more uncertainty observed in 2015 when populations may have been increasing, and 2017 and 2018, when populations may have been declining. The continued annual population decline observed since 2016 suggested there were additional strong environmental impacts that may have been compounded by the fire effects, prolonging recovery of greater sage‐grouse. Our results support others that reported negative effects to greater sage‐grouse demographics from broad‐scale fire and provide a baseline for understanding how this species responds to loss of sagebrush cover based on their life history strategy.

Historic changes of polychlorinated biphenyls (PCBs) in juvenile and adult cetaceans from the Pearl River estuary from 2003 to 2020

Polychlorinated biphenyls (PCBs), as a type of legacy persistent organic pollutants, pose significant health threats to wildlife. However, long-term residue changes and profiles of PCBs in cetaceans have not been extensively studied in the Pearl River Estuary (PRE), an important marine mammal area in China. Here, the body burdens, spatiotemporal trends, and health risks of 21 chlorobiphenyl congeners (∑21CBs) were analyzed in blubber samples collected from twelve cetacean species (n = 172) in the PRE from 2003 to 2020. Our results revealed medium levels of PCBs (316–96,233 ng g−1 lipid) compared to those reported for cetaceans elsewhere (70–370,000 ng g−1 lipid). Clear differences in PCB distribution patterns between inshore and offshore cetaceans and between odontocetes and mysticetes were also found. Both the coastal Indo-Pacific humpback dolphins (Sousa chinensis) and Indo-Pacific finless porpoises (Neophocaena phocaenoides) displayed similarly fine-scale spatial distribution patterns of PCBs, suggesting that the two cetaceans could serve as bioindicators of PCB pollution in the PRE. Additionally, both cetaceans exhibited decreasing trends in their blubber PCB concentrations over the past 20 years, likely reflecting the effective regulation of PCBs in the PRE Delta. Nevertheless, the relatively high and stable PCB-toxic equivalent (TEQ) levels detected in calf humpback dolphins during the sampling period suggested that the calves are still under the stresses of high PCB-related health risks. Our results highlight the need for more efforts to eliminate PCB contamination to prevent these cetaceans from continuous population decline and further extinction.