Ecological Characteristics Research Articles

Geographic Variation and Environmental Predictors of Nontuberculous Mycobacteria in Laboratory Surveillance, Virginia, USA, 2021-20231.

Because epidemiologic and environmental risk factors for nontuberculous mycobacteria (NTM) have been reported only infrequently, little information exists about those factors. The state of Virginia, USA, requires certain ecologic features to be included in reports to the Virginia Department of Health, presenting a unique opportunity to study those variables. We analyzed laboratory reports of Mycobacterium avium complex (MAC) and M. abscessus infections in Virginia during 2021-2023. MAC/M. abscessus was isolated from 6.19/100,000 persons, and 2.37/100,000 persons had MAC/M. abscessus lung disease. M. abscessus accounted for 17.4% and MAC for 82.6% of cases. Saturated vapor pressure was associated with MAC/M. abscessus prevalence (prevalence ratio 1.414, 95% CI 1.011-1.980; p = 0.043). Self-supplied water use was a protective factor (incidence rate ratio 0.304, 95% CI 0.098-0.950; p = 0.041). Our findings suggest that a better understanding of geographic clustering and environmental water exposures could help develop future targeted prevention and control efforts.

Standing dead wood stocks in forest stands of Middle Dnieper region (Forest-Steppe of Ukraine)

Standing dead wood is an important component of forest ecosystems of temperate zone. The aim of the article is to study the forestry and ecological features of the distribution of standing dead wood stocks in forest stands of Middle Dnieper region (Forest-steppe of Ukraine). The study was carried out based on State forest inventory data of the part of territory of state forest enterprise with a total area of 24558.6 ha in northern part of Cherkasy region. According to forest inventory data standing dead wood was found on area of 3439.4 ha or 14.0% of the total forest area. The average standing dead wood volume was the highest in forests of nature conservation, scientific, historical and cultural purposes (13.0 m3∙ha–1), somewhat lower — in forests with commercial purpose (11.0 m3∙ha–1), in protective, and recreational and health-improving forests (9.8 m3∙ha–1). Standing dead wood was found in the forest stands of 15 tree species with a total stock of 34660 m3. In those forests the average volume of by tree species ranging from 5.0 m3∙ha–1 up to 20.0 m3∙ha–1, in general for all tree species — 10.1 m3∙ha–1. In the stands of the prevailing tree species — Scots pine (Pinus sylvestris L.), black locust (Robinia pseudoacacia L.) and Common oak (Quercus robur L.) the average volume of standing dead wood was 10.4, 9.0 m3∙ha–1 and 7.5 m3∙ha–1, respectively. In the stands of the first two specified tree species, a tendency to increase the average volume of standing dead wood with an increase in the age of the stand was revealed. Standing dead wood was found in 17 out of 32 forest types that are represented in the forest fund of the studied object, with an average volume of 5.7 m3∙ha–1 (fresh eroded hornbeam dibrova) to 22.4 m3∙ha–1 (damp black alder hrud). In general, standing dead wood stocks are low, which may be caused by forestry activities (cutting). The data we obtained are important for research into the peculiarities of the formation of woody detritus stocks in the forests of Middle Dnieper region of Ukraine and nature protection functions of dead wood.

Co-Ensiling Whole-Plant Cassava with Corn Stalk for Excellent Silage Production: Fermentation Characteristics, Bacterial Community, Function Profile, and Microbial Ecological Network Features

The objective of this study was to explore excellent silage production through co-ensiling whole-plant cassava and corn stalk, and different ratios of whole-plant cassava (0%, 10%, 20%, 30%, 40%, and 50%, fresh-matter basis) co-ensiled with corn stalk were analyzed based on the silage bacterial community, function profile, and microbial ecological network features. The results demonstrated that co-ensiling 30% whole-plant cassava with 70% corn stalk could be considered an efficient mode of production. The mixed silage showed great quality, as reflected by the reduced pH value and concentrations of acetic acid, butyric acid, and ammonia nitrogen and the enhanced lactic acid concentration, V-score, and nutritional value compared with corn stalk ensiled alone. Meanwhile, co-ensiling restricted the undesirable bacterial Acetobacter fabarum of corn stalk and Pseudomonas aeruginosa of whole-plant cassava and raised the abundance of lactic acid bacteria (LAB) such as Levilactobacillus brevis, Lactiplantibacillus plantarum, Lactobacillus harbinensis, etc. Besides that, the predicted functions of the bacterial community showed large differences in mixed silage compared with whole-plant cassava or corn stalk ensiled alone. Moreover, the analysis of co-occurrence networks showed that mixed silage affected microbial network features, module numbers, and bacterial relative abundances and weakened the complexity and stability of the networks compared with whole-plant cassava single silage. Furthermore, silage microbial community composition had a huge impact on the network properties, and undesirable Pseudomonas aeruginosa played a crucial role in the complexity and stability. Overall, this study revealed the characteristics of whole-plant cassava with corn stalk mixed-silage microbial communities and co-occurrence network modules, complexity, and stability and partly clarified the microbial mechanism of co-ensiling for producing high-quality silage. The findings of this study have important implications for deeply understanding the ensiling process and precisely regulating silage fermentation quality.

Distress Labour Migration from Western Odisha - An Overview

For the past few decades, distress labour migration from western Odisha has served as a coping mechanism for impoverished households. The extremely underdeveloped areas of the KBK region, characterized by uneven development, poverty concentration, and ecological features, together with the socio-political conditions, are significant sources of distressed migrants. Despite frequent coverage in the media, a thorough investigation of the conditions and outcomes of widespread distress labour migration is noticeably lacking. Hence the present study based on macro level information looks into the aspects of distress labour migration and its underlying socio-economic factors with special focus on western belts (KBK) of Odisha It also sheds light on the impact of the MGNREGA programme in regulating the distress labour migration from the these rural areas.

Nature-based solutions for coastal protection in sheltered and exposed coastal waters: integrated monitoring program for baseline ecological structure and functioning assessment

Nature-based solutions, such as shellfish reefs, can support natural coastal defence and be a potential solution for climate-resilient shorelines in the future. In the Belgian Part of the North Sea, the “Coastbusters” projects aim to develop nature-based coastal protection by favouring subtidal mussel bed establishment on the seafloor through typical longline aquaculture techniques. Mussel beds are dependent on environmental conditions, and both influence the physical and biogeochemical features in a soft-sediment environment. Therefore, a comprehensive ecological monitoring program is essential to assess the success of future mussel bed development and its influence on the surrounding ecosystem. For establishing a monitoring baseline of the two experimental areas, a combination of conventional benthic assessment methods (grab sampling and granulometry) and non-invasive techniques (sediment profile imaging and transect diving video surveys) were utilised. Although mussel reefs did not yet develop by the time of this study, clear differences in ecological and sedimentological characteristics were found between two experimental areas (sheltered and exposed), subjected to slightly different hydrodynamic conditions. The one sheltered by coastal sandbanks was dominated by fine-muddy sand, higher species richness, biomass, and higher biological activity (burrows, fauna, and biological beds) as observed by all methods in one or another way. Moreover, functional diversity indices revealed a higher partitioning of the total available resources, suggesting more complex ecological processes in the sheltered area. Conversely, the area more exposed to the open sea was dominated by more sandy sediments, and fewer organisms were found. The combination of those different monitoring tools provides an integrated, complementary view, from different perspectives, on the biological, physical and functional characteristics of the study areas.

Water–Rock Interaction Processes in Groundwater and Flows in a Maar Lake in Central Mexico

Tropical maar lakes are distinct ecosystems with unique ecological features. To comprehend, manage, and conserve these lakes, it is essential to understand their water sources, particularly groundwater, and the hydrogeochemical processes shaping their water chemistry. This research focuses on the maar lake Alchichica in central Mexico, known for harboring 18 new and endemic species and a ring of stromatolites. With groundwater discharge as the primary source, concerns arise over anthropic extraction impacts on water levels and stromatolite survival. Sampling six wells and one piezometer revealed major ion (Ca2+, Mg2+, K+, Na+, Cl−, HCO3−, SO42−) and trace element (Fe, Al3+, SiO2) concentrations. Geochemical evolution was explored through diagrams, geological sections, and inverse geochemical models using the PHREEQC code. Findings indicate groundwater evolving along controlled flow paths, and influencing chemical composition through water–rock interactions. The lake’s unique conditions, resulting from the mixing of two flows, enable stromatolite formation. Water level reduction appears unrelated to evaporation at the sampled sites, suggesting a need for a broader study in a larger area. Analyzing the maar lake’s hydrochemistry provides valuable insights into unique characteristics supporting high endemism in this ecosystem. This research enhances our understanding of groundwater’s geochemical processes and hydrogeochemical evolution in maar lakes, with potential applications worldwide.

Ecological pollution features and health risk exposure to heavy metals via street dust and topsoil from Nkpor and Onitsha in Anambra, Nigeria.

The manuscript presents the investigation results on the pollution and risk of metal mines, and it is considered an important report on environmental pollution near mines in Nigeria, with archival value. The research involved soil sampling and heavy metal analysis for about 12 months in three metal mines. Based on these results, the paper provides information on pollution levels and hazards using well-known methods like pollution and ecological risk indexes. The increasing population in urban communities attracted by various industrial, economic and social activities causes contamination of atmospheric environment that can affect human health. We investigated heavy metal distributions, correlation coefficient among elements, ecological indices and probable health risk assessment in street dust and topsoil from Nkpor and Onitsha urban suburb, Nigeria. The mean concentration of heavy metals in car dust from Onitsha and Nkpor suburb follows thus: Fe > Mn > Cu > As > Pb > Ni > Cr. The decreasing trend of heavy metal in rooftop dust from both area: Fe > Mn > Cu > Pb > As > Ni > Cr whereas metal contents in topsoil were: Fe > Mn > Cu > Pb > Ni > Cr > As for both areas. The degree of pollution indices was characterized by contamination factor (CF), geo-accumulation factor (I-geo), pollution load index (PLI), Nemerow (PN), ecological and potential ecological risk index (ER and PERI) which indicated low pollution in the urban street environment. The results of Principal Component Analysis (PCA) and Hierarchical Cluster Analysis (HCA) showed that the estimated heavy metals displayed sources from atmospheric deposition, natural origin and anthropogenic sources. Risk assessment revealed that ingestion of dust and soil was the significant route for heavy metals exposure to the populace followed by inhalation, then dermal contact. Considering all factors, non-cancer risk was more prominent in children than adults and no significant health hazard could be attributed to both aged groups as of the period of study except for As and Ni that needs constant monitoring to avoid exceeding organ damaging threshold limit of 1 × 10-4.

The effectiveness of intercropping and agri-environmental schemes on ecosystem service of biological pest control: a meta-analysis

Plant diversification contributes to the ecological intensification of agroecosystems through pest biocontrol services provision. However, the existing evidence for the effectiveness of plant diversification in enhancing pest biocontrol services is highly uncertain across features of plant diversity and biodiversity characteristics. We undertook a comparative meta-analysis focusing on three essential crops (wheat, maize, and soybean) to investigate how diversification schemes in-field (intercropping) and Agri-environmental scheme (AES) around the field (flower strip, hedgerow and field margin) affect arthropod abundance. A random effects analysis was used to determine the role of 10 key factors underlying the effectiveness of plant diversification including biodiversity level and habitat, main and companion plant species, intercropping arrangement, the growth stage of the main crops, type of AES planting scheme, AES planting width, distance from AES plantings and geographical latitude. The overall results revealed that intercropping reduced herbivore and boosted predators and parasitoids abundance significantly, while AES successfully increased predators but not herbivores. Maize intercropping with legume and non-legume plants and row intercropping allowed for effective pest management. The abundance of predators increased in wheat fields immediately adjacent to planting around the field (AES), but this effect declined beyond 5 m from the flower strips. Our results suggest that the response of arthropod abundance to plant diversification is a compromise between spatial management scale, ecological characteristics of arthropod and plant diversification features. These results offer promising pathways for optimizing plant diversification schemes that include functional farm biodiversity across spatial and temporal scales and designing multi-functional landscapes.

A dataset of genetic diversity studies in the China Seas

Genetic diversity, a fundamental aspect of biodiversity, greatly influences the ecological and evolutionary characteristics of populations and species. Compiling genetic data is crucial as the initial step in comprehending and applying genetic resources; however, regional collating work is still insufficient, especially in marine ecosystems. Here, by conducting a thorough literature search and quality-control procedures, we provide a dataset of genetic diversity studies on marine species in the China Seas. The final dataset comprised a total of 746 studies (encompassing 840 data sets and 3658 populations) across 343 species from 1998 to 2022. For each data set, information including publication year, publication language, studied species, belonged taxonomic group, applied molecular markers, and sampling strategies (number of populations, total number of individuals, etc.) was collated to analyse the scope, strengths, and omissions of these works. This dataset offers a comprehensive overview of genetic diversity studies in the China Seas, which may help to adjust future research focuses, promote conservation and macrogenetics studies in this region, and also facilitate regional cooperation.

Stomatal response to VPD is not triggered by changes in soil-leaf hydraulic conductance in Arabidopsis or Callitris.

Stomatal closure under high VPDL (leaf to air vapour pressure deficit) is a primary means by which plants prevent large excursions in transpiration rate and leaf water potential (Ψleaf) that could lead to tissue damage. Yet, the drivers of this response remain controversial. Changes in Ψleaf appear to drive stomatal VPDL response, but many argue that dynamic changes in soil-to-leaf hydraulic conductance (Ks-l) make an important contribution to this response pathway, even in well-hydrated soils. Here, we examined whether the regulation of whole plant stomatal conductance (gc) in response to typical changes in daytime VPDL is influenced by dynamic changes in Ks-l. We use well-watered plants of two species with contrasting ecological and physiological features: the herbaceous Arabidopsis thaliana (ecotype Columbia-0) and the dry forest conifer Callitris rhomboidea. The dynamics of Ks-l and gc were continuously monitored by combining concurrent in situ measurements of Ψleaf using an open optical dendrometer and whole plant transpiration using a balance. Large changes in VPDL were imposed to induce stomatal closure and observe the impact on Ks-l. In both species, gc was observed to decline substantially as VPDL increased, while Ks-l remained stable. Our finding suggests that stomatal regulation of transpiration is not contingent on a decrease in Ks-l. Static Ks-l provides a much simpler explanation for transpiration control in hydrated plants and enables simplified modelling and new methods for monitoring plant water use in the field.

Phyllosticta taxa (Botryosphaeriales, Phyllostictaceae) from northern Thailand and southern European Russia: New host and geographical records

Phyllosticta is a cosmopolitan group of fungi found on various host plants, occurring as pathogens, endophytes and saprobes. Diseases caused by Phyllosticta commonly include leaf and fruit spots that can affect economically important plants. The genus is characterized mainly by aseptate and hyaline conidia and ascospores. Its conidia are surrounded by a mucilaginous sheath, with a single mucoid apical appendage while ascospores exhibit a mucoid cap at both ends. Given that many Phyllosticta taxa are cryptic and share similar morphologies, it is arduous to depict taxonomically relevant characters solely on the basis of morphological or ecological features. Coupled with morphological description, multi-locus phylogenetic analyses of species comprising complexes are used to broadly describe this genus and understand species boundaries. Despite several published taxonomic revisions and enumerations of Phyllosticta species, there is still considerable confusion when identifying these taxa. Herein, we establish three new host records for P. capitalensis, and one new geographical record for P. musaechinensis in Thailand, and one new host and geographical record for P. citribrasiliensis in Russia. We provide an updated phylogenetic tree based on several gene markers: ITS, LSU, ACT, GAPDH, RPB2, and TEF-1α. This includes all Phyllosticta species for which sequence data is available. Six individual Phyllosticta species complexes are accepted. In addition, we synonymize P. ericarum with P. citribrasiliensis.

The seahills and seahills ecosystems in the nearshore of Thua Thien-Hue province (Central Vietnam)

At the seabed in the nearshore, Vietnam has sandbars, shoals, bedrock knobs, rock reefs, and other landforms with elevations a few to several tens of meters higher than the seabed, which is always under the lowest astronomical tide (chart datum) and material structure of diverse compositions such as sands, gravel, boulders, blocks, etc. They have determined and warned on the chart map for the safety of navigation and the navy. These areas are significant fishing grounds due to abundant fish, shrimp, and benthic organisms. However, until now, investigation, research, and knowledge regarding these landforms’ environment, biomes, and naturals have yet to be explored. This paper presents some initial results of natural features (morphology, genetic terrain, material compositions, and types), environmental features, ecological community features (diversity, major groups of organisms, marine fish resources), and their significance in marine biomes (distribution of organisms, ecological linkage, habitats of endemic species) of a sandbar, bedrock in the nearshore in Thuan An, Tu Hien - Chan May and Lang Co - Hai Van - Son Cha of Thua Thien Hue province in the framework project of Thua Thien Hue province and National Independent Project belongs to the National Program 562 with Code Number is ĐTĐLCN.78/22. Based on these findings, the authors proposed naming this terrain “seahill” and the accompanying ecosystem “seahill ecosystems” in the nearshore of Vietnam while continuing to investigation, survey, and research.

Macroevolutionary drivers of morphological disparity in the avian quadrate.

In birds, the quadrate connects the mandible and skull, and plays an important role in cranial kinesis. Avian quadrate morphology may therefore be assumed to have been influenced by selective pressures related to feeding ecology, yet large-scale variation in quadrate morphology and its potential relationship with ecology have never been quantitatively investigated. Here, we used geometric morphometrics and phylogenetic comparative methods to quantify morphological variation of the quadrate and its relationship with key ecological features across a wide phylogenetic sample. We found non-significant associations between quadrate shape and feeding ecology across different scales of phylogenetic comparison; indeed, allometry and phylogeny exhibit stronger relationships with quadrate shape than ecological features. We show that similar quadrate shapes are associated with widely varying dietary ecologies (one-to-many mapping), while divergent quadrate shapes are associated with similar dietary ecologies (many-to-one mapping). Moreover, we show that the avian quadrate evolves as an integrated unit and exhibits strong associations with the morphologies of neighbouring bones. Our results collectively illustrate that quadrate shape has evolved jointly with other elements of the avian kinetic system, with the major crown bird lineages exploring alternative quadrate morphologies, highlighting the potential diagnostic value of quadrate morphology in investigations of bird systematics.

Genotypic Variation in Agronomic Traits and Molecular Markers among Chinese Luobuma (Apocynum spp.) Germplasm Accessions

Apocynum spp., known as Chinese Luobuma species, are perennial herbaceous plants that not only have good ecological characteristics, such as drought resistance, salt resistance, freezing resistance, high-temperature resistance and wind sand resistance, but also have good medicinal and textile value. However, studies on the genetic variation in Chinese Luobuma are rare. In this study, the genotypic variation in the agronomic traits and molecular markers among eight germplasm accessions (referred to as genotypes) of Apocynum spp. was investigated. The accessions were evaluated at two locations in China, Altay and Yuzhong, during a three-year period. Analysis of the variance in yield-related traits revealed significant genotypic variation (p < 0.05) among the eight genotypes at the early flowering and full flowering stages. There were also significant (p < 0.05) genotype × year and genotype × location × year interactions for all the traits except leaf dry weight. In comparison to those evaluated at Yuzhong, the plant height, number of branches, leaf dry weight and stem dry weight at the early flowering stage were greater in Altay, with averages of 991.0 mm, 5.52, 26.41 g and 25.35 g, respectively. There were significant (p < 0.05) differences among genotypes in terms of the quality traits measured at the early and full flowering stages. The crude protein and crude fat content for each genotype at different locations at the early flowering stage in different years ranged from 8.64 to 10.07%. The average flavone (FLA) content was 2.31 mg/100 g. Principal component analysis (PCA) revealed that the G1 genotype in Altay had a higher neutral detergent fiber content and leaf dry weight, and the G2 genotype had a larger stem thickness, branch number and stem-to-leaf ratio. Five DNA sequences, ITS, matK, psbA-trnH, rbcL and trnL-F, were selected for analysis of the molecular variance in Chinese Luobuma. Analyses of molecular variance (AMOVA) based on the nuclear DNA sequences and chloroplast DNA sequences showed that most of the variation occurred within species. Our study indicated the significant genetic variation in Chinese Luobuma for future cultivar domestication. Genotypes with high leaf dry weights and many branches are beneficial for tea production, while tall plants with long internode lengths are valuable for the production of hemp.

Use of ecosystem services and land ownership to prioritize conservation areas on Jeju Island, Republic of Korea

In the face of ecological challenges, sustainable implementation of conservation strategies necessitates a delicate balance between ecosystem services, biodiversity, land ownership, and cost considerations. This study presents a conservation strategy for Jeju Island, Republic of Korea, an area renowned for its unique ecological features. We developed the strategy by evaluating 12 scenarios involving the establishment of protected areas (PAs) and the use of other effective area-based conservation measures (OECMs). The purpose of this evaluation was not to enhance ecosystem services and biodiversity directly but rather to identify strategies that could achieve these goals in a financially feasible way, considering the various cost and land ownership factors. Our findings revealed that conservation prioritization targets are primarily located in the central and eastern regions of Jeju Island, where ecosystem services are concentrated, and levels of biodiversity are high. The expansion of conservation targets from 17% to 30% entailed increased costs, largely due to the increased inclusion of private lands and agricultural areas. The introduction of OECMs provided a means to improve ecological network and representation within conservation networks. We also found that applying penalties to improve the boundary lengths of PAs could lead to more cost-effective conservation strategies. Although expanding conservation targets to 30% led to significant shifts in land ownership patterns and increased conservation costs, the benefits to biodiversity and provision of ecosystem services were substantial. This study provided valuable insights into the determination of conservation planning through the harmonization of biodiversity prot ection, provision of ecosystem services, and consideration of economic costs related to patterns of land use and ownership. The results can aid policymakers and stakeholders in making informed decisions about resource allocation in biodiversity conservation.

Forest communities of the relict Balkan endemic Aesculus hippocastanum

Aesculus hippocastanum L. (European Horse-chestnut) constitutes a biogeographical relict species of the Balkan Peninsula, occurring in isolated and topographically distinct localities in Albania, Bulgaria, Greece and North Macedonia. Despite its great botanical, ornamental and pharmaceutical value, a thorough investigation of Ae. hippocastanum habitat diversity in its native distribution range has not been conducted yet. The present study aims at the syntaxonomic classification and ecological features of plant communities dominated by this species across its overall native distribution range. On the basis of 55 phytosociological relevés, five ecologically, floristically, and spatially well differentiated clusters were identified, with the main revealed gradients of differentiation being geographic location (longitude, latitude), altitude, annual precipitation and precipitation seasonality. The distinct microhabitats with a special refugial character where these plant communities occur meet the species’ requirement for relatively high air and soil humidity. They have allowed the preservation of Ae. hippocastanum through time highlighting their great conservational value. The last one could be useful for the implementation of some appropriate measures for effective conservation of these communities.

Kenyan Free-Tailed Bats Demonstrate Seasonal Birth Pulse Asynchrony with Implications for Virus Maintenance

Ecological information on wildlife reservoirs is fundamental for research targeting prevention of zoonotic infectious disease, yet basic information is lacking for many species in global hotspots of disease emergence. We provide the first estimates of synchronicity, magnitude, and timing of seasonal birthing in Mops condylurus, a putative ebolavirus host, and a co-roosting species, Mops pumilus (formerly Chaerephon pumilus). We show that population-level synchronicity of M. condylurus birthing is wide (~ 8.5 weeks) and even wider in M. pumilus (> 11 weeks). This is predicted to promote the likelihood of filovirus persistence under conditions of bi-annual birthing (two births per year). Ecological features underlying the magnitude of the birth pulse—relative female abundance (higher than expected for M. condylurus and lower for M. pumilus, based on literature) and reproductive rate (lower than expected)—will have countering effects on birthing magnitude. Species-specific models are needed to interpret how identified birth pulse attributes may interact with other features of molossid ebolavirus ecology to influence infection dynamics. As a common feature of wildlife species, and a key driver of infection dynamics, detailed information on seasonal birthing will be fundamental for future research on these species and will be informative for bat-borne zoonoses generally.

Geographical distribution and ecological niche dynamics of Crassostrea sikamea (Amemiya, 1928) in China's coastal regions under climate change

Global climate change drives species redistribution, threatening biodiversity and ecosystem heterogeneity. The Kumamoto oyster, Crassostrea sikamea (Amemiya, 1928), one of the most promising aquaculture species because of its delayed reproductive timing, was once prevalent in southern China. In this study, an ensemble species distribution model was employed to analyze the distribution range shift and ecological niche dynamics of C. sikamea along China's coastline under the current and future climate scenarios (RCP 2.6–8.5 covering 2050 s and 2100 s). The model results indicated that the current habitat distribution for C. sikamea consists of a continuous stretch extending from the coastlines of Hainan Province to the northern shores of Jiangsu Province. By the 2050 s, the distribution range will stabilize at its southern end along the coast of Hainan Province, while expanding northward to cover the coastal areas of Shandong Province, showing a more dramatic trend of contraction in the south and invasion in the north by the 2100 s. In RCP8.5, the southern end retracts to the coasts of Guangdong, whereas the northern end covers all of China's coastal areas north of 34°N. C. sikamea can maintain relatively stable ecological niche characteristics, while it may occupy different ecological niche spaces under future climate conditions. Significant niche expansion will occur in lower temperature. We concluded C. sikamea habitats are susceptible to climate change. The rapid northward expansion of C. sikamea may open new possibilities for oyster farming in China, but it will also have important consequences for the ecological balance and biodiversity of receiving areas. It's imperative that we closely examine and strategize to address these repercussions for a win-win situation.

Population genetic structure in the critically endangered Crocodylus intermedius (Crocodilia: Crocodylidae): a shift in perspective for conservation actions in Colombia

Abstract Conservation actions for threatened species and populations aim to preserve their genetic diversity and prevent issues such as inbreeding or outbreeding depressions. This perspective has been incorporated into the management plans proposed for the critically endangered Orinoco crocodile (Crocodylus intermedius) in Colombia. A previous study, which used mitochondrial cytochrome b and cytochrome c oxidase subunit I, suggested that the in situ population management of the Orinoco crocodile in Colombia does not face genetic restrictions. In this research, we re-evaluated this proposal by using an expanded sampling and additional molecular markers (microsatellite nuclear DNA and the mitochondrial D-loop) that have successfully identified crucial information at the population level in other crocodilians. Our findings reveal, for the first time, a pattern of population structure consisting of three genetic clusters with geographical correspondence, matching three ecoregions in the Colombian Orinoco basin. This pattern might be a historical and current consequence of the ecological, bioclimatic, and/or geographical features of the ecoregion. Additionally, we examined the correspondence with the genetic clusters of the confiscated individuals that formed part of the initial population (F0) of the Colombian ex situ species population and successfully assigned most of them to one of these clusters. The genetically distinct clusters should be regarded as independent management units for conserving and managing the species in Colombia.

Determining the response of ecological drought to meteorological and groundwater droughts in Northwest China using a spatio-temporal matching method

Meteorological drought and groundwater drought in ecologically fragile regions may induce ecological drought. Currently, there is no effective method for revealing the response mechanism of ecological drought to meteorological drought and groundwater drought. Taking Northwest China (NWRC) as an example, meteorological drought, groundwater drought and ecological drought were evluated by standardized pricipitation index, standardized groundwater storage anomaly index, and standardized ecological water deficit index, respectively. The spatio-temporal matching method was improved for identifying propagation between three types of drought events. Then, a model of ecological drought characteristics in response to meteorological drought and groundwater drought characteristics was constructed based on the copula function. Finally, the Bayesian model was used to determine the thresholds of meteorological drought and groundwater drought that trigger ecological drought events at different drought levels. The key findings are as follows. (1) A total of 31 pairs of meteorological-groundwater-ecological drought events with a genetic relationship were identified. The ecological drought events with larger severity were caused by the joint effect of meteorological and groundwater drought, and most of them occurred before the 21st century. (2) The optimal response models of the affected area, duration, and intensity of ecological drought events were Gumbel copula driven by the affected area of meteorological drought, the Student t copula driven by the duration of groundwater drought, and the Joe copula driven by the severity of meteorological and ecological drought, respectively. (3) The thresholds and the corresponding curves of meteorological drought and groundwater drought to trigger mild, moderate, severe, and extreme ecological drought events were obtained. Results of this study can provide valuable information for early warning of ecological drought.