Hasil untuk "General. Including nature conservation, geographical distribution"

L. Tedersoo, M. Bahram, Sergei Põlme et al.

Introduction The kingdom Fungi is one of the most diverse groups of organisms on Earth, and they are integral ecosystem agents that govern soil carbon cycling, plant nutrition, and pathology. Fungi are widely distributed in all terrestrial ecosystems, but the distribution of species, phyla, and functional groups has been poorly documented. On the basis of 365 global soil samples from natural ecosystems, we determined the main drivers and biogeographic patterns of fungal diversity and community composition. Direct and indirect effects of climatic and edaphic variables on plant and fungal richness. Line thickness corresponds to the relative strength of the relationships between the variables that affect species richness. Dashed lines indicate negative relationships. MAP, mean annual precipitation; Fire, time since last fire; Dist. equator, distance from the equator; Ca, soil calcium concentration; P, soil phosphorus concentration; pH, soil pH. Rationale We identified soil-inhabiting fungi using 454 Life Sciences (Branford, CN) pyrosequencing and through comparison against taxonomically and functionally annotated sequence databases. Multiple regression models were used to disentangle the roles of climatic, spatial, edaphic, and floristic parameters on fungal diversity and community composition. Structural equation models were used to determine the direct and indirect effects of climate on fungal diversity, soil chemistry, and vegetation. We also examined whether fungal biogeographic patterns matched paradigms derived from plants and animals—namely, that species’ latitudinal ranges increase toward the poles (Rapoport’s rule) and diversity increases toward the equator. Last, we sought group-specific global biogeographic links among major biogeographic regions and biomes using a network approach and area-based clustering. Results Metabarcoding analysis of global soils revealed fungal richness estimates approaching the number of species recorded to date. Distance from equator and mean annual precipitation had the strongest effects on richness of fungi, including most fungal taxonomic and functional groups. Diversity of most fungal groups peaked in tropical ecosystems, but ectomycorrhizal fungi and several fungal classes were most diverse in temperate or boreal ecosystems, and many fungal groups exhibited distinct preferences for specific edaphic conditions (such as pH, calcium, or phosphorus). Consistent with Rapoport’s rule, the geographic range of fungal taxa increased toward the poles. Fungal endemicity was particularly strong in tropical regions, but multiple fungal taxa had cosmopolitan distribution. Conclusions Climatic factors, followed by edaphic and spatial patterning, are the best predictors of soil fungal richness and community composition at the global scale. Richness of all fungi and functional groups is causally unrelated to plant diversity, with the exception of ectomycorrhizal root symbionts, suggesting that plant-soil feedbacks do not influence the diversity of soil fungi at the global scale. The plant-to-fungi richness ratio declined exponentially toward the poles, indicating that current predictions—assuming globally constant ratios—overestimate fungal richness by 1.5- to 2.5-fold. Fungi follow similar biogeographic patterns as plants and animals, with the exception of several major taxonomic and functional groups that run counter to overall patterns. Strong biogeographic links among distant continents reflect relatively efficient long-distance dispersal compared with macro-organisms. Fungi play major roles in ecosystem processes, but the determinants of fungal diversity and biogeographic patterns remain poorly understood. Using DNA metabarcoding data from hundreds of globally distributed soil samples, we demonstrate that fungal richness is decoupled from plant diversity. The plant-to-fungus richness ratio declines exponentially toward the poles. Climatic factors, followed by edaphic and spatial variables, constitute the best predictors of fungal richness and community composition at the global scale. Fungi show similar latitudinal diversity gradients to other organisms, with several notable exceptions. These findings advance our understanding of global fungal diversity patterns and permit integration of fungi into a general macroecological framework. Global metagenomics detects hotspots of fungal diversity and macroecological patterns and indicates that plant and fungal diversity are uncoupled. [Also see Perspective by Wardle and Lindahl] Assessing fungal diversity worldwide Fungi are hyperdiverse but poorly known, despite their ecological and economic impacts. Tedersoo et al. collected nearly 15,000 topsoil samples from 365 sites worldwide and sequenced their genomes (see the Perspective by Wardle and Lindahl). Overall, they found a striking decline in fungal species richness with distance from the equator. For some specialist groups though, diversity depended more on the abundance of host plants than host diversity or geography. The findings reveal a huge gap between known and described species and the actual numbers of distinct fungi in the world's soils. Science, this issue 10.1126/science.1256688; see also p. 1052

N. Bassi, M. Kumar, Anuradha Sharma et al.

Abstract Study region India. Study focus India has a wealth of wetland ecosystems that support diverse and unique habitats. These wetlands provide numerous ecological goods and services but are under tremendous stress due to rapid urbanization, industrialization and agricultural intensification, manifested by the shrinkage in their areal extent, and decline in the hydrological, economic and ecological functions they perform. This paper reviews the wetland wealth of India in terms of their geographic distribution and extent, ecosystem benefits they provide, and the various stresses they are exposed to. The paper also discusses the efforts at management of these fragile ecosystems, identifies the institutional vacuum and suggests priority area where immediate attention is required in order to formulate better conservation strategies for these productive systems. New hydrological insights for the region It has been found that management of wetlands has received inadequate attention in the national water sector agenda. As a result, many of the wetlands are subject to anthropogenic pressures, including land use changes in the catchment; pollution from industry and households; encroachments; tourism; and over exploitation of their natural resources. Further, majority of research on wetland management in India relates to the limnological aspects and ecological/environmental economics of wetland management. But, the physical (such as hydrological and land use changes in the catchment) and socio-economic processes leading to limnological changes have not been explored substantially.

موسی عنبری, مرجان خاکساری رنانی

امروزه وجود نابرابری‌های فضایی و فاصله‌های درآمدی و سرمایه‌ای میان نواحی مختلف جامعه، به‌عنوان یکی از موانع مهم توسعۀ پایدار به‌حساب می‌آید. نابرابری‌های میان مناطق کم‌برخوردار (مرزی یا غیرمرزی) و مناطق برخوردار از توسعه، و شکاف‌های شهری ‌ـ ‌روستایی، مهم‌ترین مصداق نابرابری‌های فضایی و منطقه‌ای هستند. این مقاله با روش توصیفی ـ تحلیلی، بر مبنای تحلیل ثانویۀ داده‌های موجود، میزان یکپارچگی یا شکاف مناطق شهری و روستایی ایران را برحسب چهار متغیر مکان‌های استقرار جمعیت، بخش‌های عمدۀ اقتصادی و تولیدی، میزان و توزیع فقر، و شکاف درآمدی و هزینه‌ای در چهار دهۀ اخیر مورد مطالعه قرار داده ‌است. ارزیابی عملکرد نظام برنامه‌ریزی فضایی در کشور نشان می‌دهد این نظام با نوعی رویکرد بخشی و غیرآمایشی، با تأکید بر دو محور «تمرکزگرایی» و «شهرگرایی»، بر نابرابری‌ و فاصلۀ میان مناطق پیرامونی و مناطق مرکزی کشور از یک سو و مناطق شهری و روستایی از سوی دیگر افزوده ‌‌است. طی چهار دهۀ اخیر، نوعی شهرنشینی روزافزون، بی‌رویه و گاهی ناموزون به ‌ضرر پایداری و تعادل جمعیت در مناطق شهری کوچک و مناطق روستایی اتفاق افتاده که لزوماً با ظرفیت‌های منطقه‌ای متناسب نبوده ‌‌است. شهرهای بزرگ جاذب جمعیت کار، نوعی زندگی توأم با فقر را در بخش‌های حاشیه‌ای و روستایی ایجاد کرده ‌‌است. در طی این سال‌ها، با وجود کاهش معنادار فقر مطلق در جامعه، همچنان بار فقر بر دوش روستاییان، آن‌هم بیشتر در مناطق کم‌برخوردار سنگینی می‌کند. شاخص‌های درآمد و هزینه نیز به نفع شهرنشینان بوده‌‌ است. به‌طور‌ کلی داده‌های کلان در کشور نشان می‌دهد هرجا پیوندهای شهری‌ ـ ‌روستایی برقرار و تقویت شده، نابرابری‌های منطقه‌ای و شهری ـ‌ روستایی کاهش یافته ‌است.

Aleksandra Krasilnikova, Michele Di Iorio, Emanuele Antenucci et al.

The current study aimed to compare the effects of decreasing osmolality in glucose-based extenders containing methanol alone versus a methanol-ethylene glycol combination on the post-thaw motility of Mediterranean brown trout (Salmo cettii) spermatozoa. Milt was collected from mature males in the Biferno River, Southern Italy, and cryopreserved using a control cryomedium (150 mM glucose with 7.5% methanol) and experimental variants with reduced glucose (100 mM, 50 mM) paired with methanol alone or combined with 2.5% ethylene glycol. Samples were cryopreserved in 0.25 mL straws with a final sperm concentration of 3.0 × 109 spermatozoa/mL, corresponding to 750 × 106 spermatozoa/straw. Sperm motility and kinematic parameters of Mediterranean brown trout were assessed for fresh sperm and post-thaw samples cryopreserved in various cryomedia. Fresh sperm exhibited robust motility (89.0 ± 8.4%) and curvilinear velocity (VCL, 121.2 ± 22.4 µm/s), while the control cryomedium preserved motility at 65.9 ± 12.9% and VCL at 117.6 ± 26.1 µm/s; the experimental 100 mM glucose with 7.5% methanol and 2.5% ethylene glycol treatment yielded comparable motility (65.6 ± 11.6%) but reduced VCL (81.5 ± 16.1 µm/s, p < 0.05). Other treatments showed diminished efficacy, particularly at 50 mM glucose. These findings reveal that a hypotonic extender with methanol-ethylene glycol synergy sustains motility after cryopreservation despite lower glucose levels, demonstrating that the osmotic threshold of extender can be lowered to 100 mOsm/kg without compromising salmonid sperm function. This approach offers a practical tool for conserving S. cettii, supporting broader restoration efforts amid escalating environmental pressures.

Jian Wang, Zhuo Zhao, Zeng Jie Wang et al.

Geographic Question Answering (GeoQA) addresses natural language queries in geographic domains to fulfill complex user demands and improve information retrieval efficiency. Traditional QA systems, however, suffer from limited comprehension, low retrieval accuracy, weak interactivity, and inadequate handling of complex tasks, hindering precise information acquisition. This study presents GeoRAG, a knowledge-enhanced QA framework integrating domain-specific fine-tuning and prompt engineering with Retrieval-Augmented Generation (RAG) technology to enhance geographic knowledge retrieval accuracy and user interaction. The methodology involves four components: (1) A structured geographic knowledge base constructed from 3267 corpora (research papers, monographs, and technical reports), categorized via a multi-agent approach into seven dimensions: semantic understanding, spatial location, geometric morphology, attribute characteristics, feature relationships, evolutionary processes, and operational mechanisms. This yielded 145234 classified entries and 875432 multi-dimensional QA pairs. (2) A multi-label text classifier based on BERT-Base-Chinese, trained to analyze query types through geographic dimension classification. (3) A retrieval evaluator leveraging QA pair data to assess query-document relevance, optimizing retrieval precision. (4) GeoPrompt templates engineered to dynamically integrate user queries with retrieved information, enhancing response quality through dimension-specific prompting. Comparative experiments demonstrate GeoRAG's superior performance over conventional RAG across multiple base models, validating its generalizability. This work advances geographic AI by proposing a novel paradigm for deploying large language models in domain-specific contexts, with implications for improving GeoQA systems scalability and accuracy in real-world applications.

Anjana S, Sudheesh Kattumannil

Log symmetric distributions are useful in modeling data which show high skewness and have found applications in various fields. Using a recent characterization for log symmetric distributions, we propose a goodness of fit test for testing log symmetry. The asymptotic distributions of the test statistics under both null and alternate distributions are obtained. As the normal-based test is difficult to implement, we also propose a jackknife empirical likelihood (JEL) ratio test for testing log symmetry. We conduct a Monte Carlo Simulation to evaluate the performance of the JEL ratio test. Finally, we illustrated our methodology using different data sets.

R. Elmhirst

Roller MaMing

Our recent investigation in China encompasses the species and number studies of eagles in captivity, study of methods and tools used to capture raptors in the field, investigation into whether there is trade (and at which level), estimation of damage to wild populations and their resources, assessment of the current situation in the field, negative factors, conflicts between laws and traditional culture (such as the Intangible Cultural Heritage), and how to solve and effectively manage them.

Pavel M. Shukov

The article presents current results of a study of Short-Toed Eagle (Circaetus gallicus) distribution, abundance, and ecology in Nizhny Novgorod region. We designed a network of auto routes to survey the area and subsequently covered it in a four-wheel drive vehicle combined with walking through upland bogs and forest margins by foot. Observations were carried out in 30 districts of the region. Hunting Short-Toed Eagles were observed from natural hills through binoculars. Nests were detected based on adult birds’ observations and analysis of satellite images of the surveyed areas. Photo and video recording of birds and nests was carried out using a SLR camera and a quadcopter. In 2015–2023 observations were carried out on 49 breeding territories.

Mona Schirmer, Dan Zhang, Eric Nalisnick

Knowing if a model will generalize to data 'in the wild' is crucial for safe deployment. To this end, we study model disagreement notions that consider the full predictive distribution - specifically disagreement based on Hellinger distance, Jensen-Shannon and Kullback-Leibler divergence. We find that divergence-based scores provide better test error estimates and detection rates on out-of-distribution data compared to their top-1 counterparts. Experiments involve standard vision and foundation models.

Victor Monzon Baeza, Flor Ortiz, Eva Lagunas et al.

Among the recent advances and innovations in satellite communications, Non-Geostationary Orbit (NGSO) satellite constellations are gaining popularity as a viable option for providing widespread broadband internet access and backhauling services. However, a more complex ground segment with multiple ground stations is necessary due to these satellites' high speeds and low altitudes. The complete dimensioning of the ground segment, including gateway optimal placement and the number of ground access points, remains a relevant open challenge. In this article, we provide an overview of the key factors that shall be considered for NGSO gateway station geographical planning. Subsequently, we propose a ground segment dimensioning approach that combines several criteria, such as rain attenuation, elevation angle, visibility, geographical constraints, and user traffic demands. The operational concept is first discussed, followed by a methodology that combines all these constraints into a single map-grid to select the best position for each gateway. Furthermore, a case study is presented, which demonstrates the performance of the proposed methodology, for one example constellation. Finally, we highlight relevant open challenges and key research directions in this area.

Niu Li, Niu Li, Ming Nie et al.

Grazing prohibition has been used for some conservation purposes in salt marshes. However, the impact of this measure on microbe-mediated key nitrogen removal processes remains poorly understood. Therefore, this study assessed the impact of grazing prohibition on potential rates of nitrification and denitrification under short- and long-term grazing prohibition in high and middle elevation of the Dongtan salt marsh on Chongming Island, China. Compared with short-term grazing prohibition, we found that long-term grazing prohibition significantly increased nitrification and denitrification (except for nitrification in the high marsh), which indicates that the nitrogen removal ability of the salt marsh was improved along with the grazing prohibition time. Furthermore, we found that nitrification and denitrification in the high marsh were largely affected by NH4+ and soil moisture, respectively. Nitrification and denitrification in the middle marsh were mainly controlled by soil organic carbon (SOC) and nirS gene abundances, respectively. Our results indicate that the implementation of scientific and reasonable grazing prohibition policies in salt marshes has great potential to restore their ecosystem functions, maintain their ecosystem balance and realize their sustainable development.

Rachel A. Farrow, Helen E. Roy, Peter M. J. Brown

The invasive alien species Harmonia axyridis (Coleoptera: Coccinellidae) was first observed in the UK in 2004. Previous studies have demonstrated the adverse effects on other species of H. axyridis during its early stages of establishment. However, habitat factors are important in determining distribution and population trends of ladybirds. Whilst the abundance of H. axyridis is well known in the UK within urban and other managed habitats, much less is known about its abundance in the wider countryside. Here we present the results of surveys from rural woodland habitats to assess whether or not H. axyridis dominates coccinellid communities in these rural habitats. Additionally, we explored the relationship between coccinellid and aphid abundance within these habitats. All field sites were in Cambridgeshire or Suffolk, East Anglia, UK and were surveyed between May and October 2016 and 2017. Three deciduous sites and three coniferous sites were included in the study. Surveys were conducted using a standardised approach involving sweep-netting within grass margins and tree beating to sample ladybirds from trees. Three distinct vegetation structures or layers were surveyed within both the coniferous and deciduous sites; tree, shrub and herb layer. All captured coccinellids were identified to species-level. Seventeen species of coccinellid and over 1300 individuals were recorded during the study period from two distinct site types (deciduous, coniferous). Species richness was lower at deciduous sites (n = 12) in comparison to coniferous (n = 16) sites. The coccinellid community also did not appear to be dominated by H. axyridis at rural sites, in contrast to urban areas. Deciduous woodland appeared to be a lesser preferred habitat of H. axyridis than coniferous woodland. Additionally, there was a distinct difference in the coccinellid community in relation to vegetation structure (across the tree, shrub and herb layers) between coniferous and deciduous sites. Our results indicate that there appear to be distinct native coccinellid communities at deciduous and coniferous sites. We discuss the way in which rural woodlands could act as a refuge for some native coccinellids.

Federico Pinna, Annalisa Caragnano, Annalisa Caragnano et al.

Understanding how coralline algae may acclimatize to ocean warming is important to understand their survival over the coming century. Taking advantage of natural differences in temperature conditions between coastal areas in Sardinia (Italy) and between depths, the responses in terms of biological traits to warming of the crustose coralline alga Lithophyllum stictiforme, a key bioconstructor of coralligenous reefs in the Mediterranean, were evaluated in the field by two innovative transplant experiments where translocated specimens were used as controls. Results of the first experiment (algae cross transplanted between a cold and a warm site at two depths, 23 and 34 m) showed that the marginal growth of the alga and production of conceptacles were higher in the cold site, regardless of the treatment (transplant and translocation) and depth. However, growth in thickness in algae transferred from the cold to the warm site was higher at 34 m of depth, where they had a better performance than the local (translocated) algae. Results of the second experiment (algae transplanted from 34 m to 15 m of depth under different light irradiance manipulations) evidenced that the increase in temperature of +4°C was tolerated by thalli transplanted at 15 m, but that thallus growth and conceptacles production was negatively affected by the higher light irradiance. These results suggest an overall good adaptability of L. stictiforme under warmer conditions, even those due to thermocline deepening. Overall, these results encourage consideration of the use of transplants of this bioconstructor in future restoration actions of coralligenous habitats.

Gaowei Cao, Gui-Qiang G. Chen

We are concerned with the minimal entropy conditions for one-dimensional scalar conservation laws with general convex flux functions. For such scalar conservation laws, we prove that a single entropy-entropy flux pair $(η(u),q(u))$ with $η(u)$ of strict convexity is sufficient to single out an entropy solution from a broad class of weak solutions in $L^\infty_{\rm loc}$ that satisfy the inequality: $η(u)_t+q(u)_x\leq μ$ in the distributional sense for some non-negative Radon measure $μ$. Furthermore, we extend this result to the class of weak solutions in $L^p_{\rm loc}$, based on the asymptotic behavior of the flux function $f(u)$ and the entropy function $η(u)$ at infinity. The proofs are based on the equivalence between the entropy solutions of one-dimensional scalar conservation laws and the viscosity solutions of the corresponding Hamilton-Jacobi equations, as well as the bilinear form and commutator estimates as employed similarly in the theory of compensated compactness.

Jonathan D. Cook, Evan H. C. Grant, Jeremy T. H. Coleman et al.

Abstract The virus that causes COVID‐19 likely evolved in a mammalian host, possibly Old‐World bats, before adapting to humans, raising the question of whether reverse zoonotic transmission to bats is possible. Wildlife management agencies in North America are concerned that the activities they authorize could lead to transmission of SARS‐CoV‐2 to bats from humans. A rapid risk assessment conducted in April 2020 suggested that there was a small but significant possibility that SARS‐CoV‐2 could be transmitted from humans to bats during summer fieldwork, absent precautions. Subsequent challenge studies in a laboratory setting have shed new information on these risks, as has more detailed information on human epidemiology and transmission. This inquiry focuses on the risk to bats from winter fieldwork, specifically surveys of winter roosts and handling of bats to test for white‐nose syndrome or other research needs. We use an aerosol transmission model, with parameter estimates both from the literature and from formal expert judgment, to estimate the risk to three species of North American bats, as a function of several factors. We find that risks of transmission are lower than in the previous assessment and are notably affected by chamber volume and local prevalence of COVID‐19. Use of facemasks with high filtration efficiency or a negative COVID‐19 test before field surveys can reduce zoonotic risk by 65 to 88%.