Influence Of Climatic Factors Research Articles

The influence of climatic and human-induced factors on the spatial distribution of invasive plant species richness across the Loess Plateau

Biological invasion poses a critical global issue, leading to substantial detrimental impacts on biodiversity, the environment, and the economy. The objective of the study is to offer a thorough understanding of how both climatic and human-induced elements impact the geographic richness of invasive plant species across the Loess Plateau. We evaluate the distribution of invasive plant species at the county level across the Loess Plateau by examining herbarium records from China. We incorporate 16 climatic and anthropogenic variables to depict the local environmental settings. Furthermore, we apply a classification and regression tree approach to investigate the correlation between the richness of invasive plant species and the identified factors. Our study demonstrates that a total of 401 invasive plant species are identified, which are spread across 249 genera and 61 families. Among these, the Asteraceae family stands out as the most prevalent, trailed by Poaceae and Fabaceae. The spatial distribution of invasive plant species richness reveals a notable trend, with the highest frequencies found in the southeastern parts of the region and the lowest in the northwestern areas. It is noteworthy that regions with higher levels of economic advancement tend to harbor a more significant abundance of invasive plant species. The richness of invasive plant species on the Loess Plateau is predominantly shaped by a combination of climatic and human variables, such as annual precipitation, gross domestic product, maximum temperature of warmest month, and minimum temperature of coldest month. To fully comprehend the ecological and biological mechanisms underlying the diversity of invasive plant species on the Loess Plateau, a pioneering conceptual framework has been established. Our study suggests that achieving a harmonious equilibrium among development, conservation, and invasion mitigation is essential for recognizing emerging risks associated with habitat alterations, climate change, and socio-economic advancements in arid regions.

Research on improving the efficiency of electricity transmission

A study of ways to modernize the current-carrying part of overhead lines to improve the efficiency of electricity transmission through the use of innovative types of wires was conducted. The technical and economic characteristics of AC, ACCR, and AERO-Z wires were analyzed. The results of the analysis revealed that further improvement of the design of AC wires should be based on new progressive developments that would meet such technical requirements as reliability, survivability and durability; corrosion resistance; high adhesion ability; resistance to vibration during operation under the influence of adverse climatic factors; resistance to environmental temperature effects. As an innovative solution to this issue, high-temperature (ACCR) and specially designed (AERO-Z) wires have been developed in foreign countries. A comparative analysis of the types of wires used in Ukrainian power grids with innovative types of wires used in power grids of foreign countries was performed. The results of the comparison of AC, ACCR, and AERO-Z wires show that the factor that limits the scope of application of ACCR wire, even for spans with extremely high requirements for power transmission characteristics, is its extremely high cost. This is because the technical characteristics of this wire are better than those of AC wire and it has a relatively low cost compared to ACCR wire, and its special design is adapted to adverse climatic conditions that affect the characteristics of electricity transmission.

Research on improving the efficiency of electricity transmission

A study of ways to modernize the current-carrying part of overhead lines to improve the efficiency of electricity transmission through the use of innovative types of wires was conducted. The technical and economic characteristics of AC, ACCR, and AERO-Z wires were analyzed. The results of the analysis revealed that further improvement of the design of AC wires should be based on new progressive developments that would meet such technical requirements as reliability, survivability and durability; corrosion resistance; high adhesion ability; resistance to vibration during operation under the influence of adverse climatic factors; resistance to environmental temperature effects. As an innovative solution to this issue, high-temperature (ACCR) and specially designed (AERO-Z) wires have been developed in foreign countries. A comparative analysis of the types of wires used in Ukrainian power grids with innovative types of wires used in power grids of foreign countries was performed. The results of the comparison of AC, ACCR, and AERO-Z wires show that the factor that limits the scope of application of ACCR wire, even for spans with extremely high requirements for power transmission characteristics, is its extremely high cost. This is because the technical characteristics of this wire are better than those of AC wire and it has a relatively low cost compared to ACCR wire, and its special design is adapted to adverse climatic conditions that affect the characteristics of electricity transmission.

Temporal and spatial evolution of net primary productivity in the Three-River Headwaters Region under phenological changes and anthropogenic influence.

Understanding the spatiotemporal changes in net primary productivity (NPP) and the driving factors behind these changes in climate-vulnerable regions is crucial for ecological conservation. This study simulates the actual NPP (NPPA) and climate potential NPP (NPPC) in the Three-River Headwaters Region from 2000 to 2020. The Theil-Sen Median method and Mann-Kendall mutation analyses are employed to explore their spatiotemporal variation patterns, while geographic weighted regression and machine learning are used to investigate the influence of anthropogenic activities and climatic factors on NPPA, the results indicate that the average NPPA across the entire region over multiple years is 382.506 , which is 0.132 times the average annual NPPC over the past 21years, showing an overall distribution pattern of low in the northwest and high in the southeast. The annual increase in NPPA from 2000 to 2020 is approximately 1.034 . The source region of the Yangtze River shows the largest improvement in vegetation, with 74.1% of the area showing improvement. Between 2002 and 2003, the annual NPPA in the Three-River Headwaters Region experienced a sudden change, lagging behind the NPPC change by 1year, and after 2005, the upward trend in NPPA became more pronounced. The impact of anthropogenic activities on NPPA shifted from positive to negative to positive from 2000 to 2020, with significant impact areas mainly concentrated in the northeast and a few areas in the central and southern parts. The proportion of areas with extremely significant impact increased from 1.9% in 2000 to 3.7% in 2020. Over the past 21years, the main factors influencing NPPA changes in the Three-River Headwaters Region have been soil moisture and precipitation, with the influence of different climate factors on NPP changing over time. Additionally, NPP is more sensitive to changes in altitude in low-altitude areas. This study can provide more accurate theoretical support for ecological environment assessment and subsequent protection efforts in the Three-River Headwaters Region.

The influence of climatic and human-induced factors on the spatial distribution of invasive plant species richness across the Loess Plateau

The influence of climatic and human-induced factors on the spatial distribution of invasive plant species richness across the Loess Plateau

Relationship between climatic factors and the flea index of two plague hosts in Xilingol League, Inner Mongolia Autonomous Region

Climatic factors are closely associated with the occurrence of vector-borne diseases, and they also influence the distribution of vectors. The occurrence of plague is closely related to the population dynamics of fleas and their host animals, as well as climatic conditions. This study focuses on Xilingol League, utilizing climatic and flea index data from 2012 to 2021. Spearman correlation and "Boruta" importance analysis are conducted to screen for climatic variables. A generalized additive model (GAM) is employed to investigate the influence of climatic factors and rodent density on the flea index. GAM analysis reveals distinct trends in flea index among different rodent hosts. For Meriones unguiculatus, the flea index declines with increased density and with higher humidity, yet rises with greater lagged sunshine duration. For Spermophilus dauricus, an initial increase in flea index with density is observed, followed by a decrease, and a rise in the index is noted when ground temperatures are low. This study reveals the nonlinear interactions and lag effects among climatic factors, density, and flea index. Climatic factors and density variably influence the flea index of two Yersinia pestis hosts. This research advances the prediction and early warning efforts for plague control, providing a theoretical basis for rodent and flea eradication strategies.

Features of the Development of the Circular Economy in Livestock Production of the Agricultural Sector in the Context of Climate Change

The goal is to analyze the current state of development of agro-industrial production in the context of circular and climate economy of Kazakhstan with emphasis on identifying the elements of its key aspects in livestock farming and determining the influence of climatic factors on this economic system. Methods – statistical analysis and graphical interpretation of data, comparative assessment of linear and circular economic models. Materials from scientific publications, regulations, as well as interviews with experts were used. Results - recommendations for transition to sustainable circular economy structure in agricultural sector of Kazakhstan have been developed, aimed at increasing the efficiency of resource potential, reducing negative impact on environment and creating new opportunities for business and innovation in the country's agro-industrial complex. Measures have been proposed to improve the infrastructure for processing and disposal of agricultural waste and use of modern technologies in the industry. Conclusions - implementation of the principles of circular economy helps to increase energy efficiency and reduce negative impact on biosphere and ecosystems, creating conditions for expanding the scope of innovative entrepreneurship - “green” business: new jobs, appropriate infrastructure, “green” logistics, etc. Principles of circular economy: circular supply (limited resources are replaced by completely renewable sources); extending the life cycle of products through modernization and reconstruction; recycling (restoration and recycling of product residues). Resourceefficient modification is an opportunity for innovation at all stages of new value formation, which gives not only good final results, but also leads to them with lower material, energy and environmental costs.

Influence of climatic factors on spatio-temporal variabilities in the occurrence of aflatoxins in major food grains available at retail shops in Bangladesh

In Bangladesh, little is known about the role of climatic factors influencing spatio-temporal occurrence among different food grains of aflatoxins, which have been linked to liver cancer cases and other health hazards. In this study, 252 food grain samples of 10 types were collected from retail markets at 18 districts, pre-monsoon, monsoon and post-monsoon seasons during February-September, 2018. Occurrence and concentration of total aflatoxins in the samples were analysed by a direct competitive enzyme-linked immunosorbent assay, and compared with climatic data (temperature, humidity, rainfall, and sunshine hours). Contamination of aflatoxins was found in approx. 38% (n=96) of the total samples, with highest occurrence in groundnuts (82%), followed by corn grains (70%), chick pea (54.5%), wheat grain (50%) and green gram (42.9%). Aflatoxins occurrence was moderate in split chick pea (30.8%), yellow pea (28.2%), black gram (27.8%), and lentils (27.6%), while the lowest in grass pea (17.6%). Aflatoxins concentration was found to exceed the European Union permissible limit (≤5 µg kg-1) in 33 (13.1%) samples. Overall, approximately 5.6%, 7.5%, and 25.0% samples were contaminated with high (10-19 ppb), medium (5-9 ppb) and low (1-4 ppb) concentrations of aflatoxins, respectively. High level concentration of aflatoxins was more frequent in groundnut (36%) and wheat grain (20%), in comparison to other types. Occurrence of aflatoxins during pre-monsoon was detected among 21% (19/91) samples, which increased to ca. 30% (36/119) during monsoon, and 98% (41/42) during post-monsoon. However, aflatoxins mean concentration during post-monsoon was comparatively low than the other seasons. Variations in aflatoxins monthly prevalence correlated significantly with relative humidity (p ≤ 0.01) and rainfall (p≤ 0.05), when a 1-month time lag was considered. Therefore, predisposing climatic conditions, i.e., rainfall incidences and persistence of higher relative humidity in the previous month(s), have salient influence on aflatoxins occurrence, potentially impacting both pre-harvest and stored food grains. This study underscores the need of a more holistic monitoring of aflatoxins in agricultural products for a longer term, and adoption of proper intervention measures for food grains while being stored and before consumption. Asian Australas. J. Food Saf. Secur. 2024, 8(2), 32-47

The Influence of Climatic Factors on the Provocation of Epileptic Seizures.

Background/Objectives: Recent studies provide the first indications of the impact of climate factors on human health, especially with individuals already grappling with internal and neurological conditions being particularly vulnerable. In the face of escalating climate change, our research delves into the specific influence of a spectrum of climatic factors and seasonal variations on the hospital admissions of patients receiving treatment for epileptic seizures at our clinic in Kaiserslautern. Methods: Our study encompassed data from 9366 epilepsy patients who were admitted to hospital due to epileptic seizures. We considered seven climate parameters that Germany's National Meteorological Service made available. We employed the Kruskal-Wallis test to examine the correlation between the frequency of admittance to our hospital in the mentioned patient group and seasons. Furthermore, we used conditional Poisson regression and distributed lag linear models (DLMs) to scrutinize the coherence of the frequency of patient admittance and the investigated climate parameters. The mentioned parameters were also analyzed in a subgroup analysis regarding the gender and age of patients and the classification of seizures according to ILAE 2017. Results: Our results demonstrate that climatic factors, such as precipitation and air pressure, can increase the frequency of hospital admissions for seizures in patients with general-onset epilepsy. In contrast, patients with focal seizures are less prone to climatic changes. Consequently, admittance to the hospital for seizures is less affected by climatic factors in the latter patient group. Conclusions: The present study demonstrated that climatic factors are possible trigger factors for the provocation of seizures, particularly in patients with generalized seizures. This was determined indirectly by analyzing the frequency of seizure-related emergency admissions and their relation to prevailing climate factors. Our study is consistent with other studies showing that climate factors, such as cerebral infarcts or cerebral hemorrhages, influence patients' health.

Indonesian Climatic Factors and Its Effect on Cocoa Productivity

One of the important aspects in cocoa cultivation is productivity, as it is related to the ability of national cocoa producers to meet market demand. Cocoa productivity is affected by many factors, including climate factors. On this basis, this study aims to determine the trend of national cocoa productivity and climatic factors (maximum temperature, minimum temperature, mean temperature, and rainfall) and to determine the influence of climatic factors on cocoa productivity. By applying a descriptive method, this research utilized secondary data with a time span between 1961-2021, which were analyzed using quadratic regression model. From the analysis, it was clear that there had been increasing tendency for national cocoa productivity, maximum temperature, minimum temperature, mean temperature and rainfall from year to year. Meanwhile, the climatic factors that affect cocoa productivity are the maximum temperature, minimum temperature, and mean temperature with an optimum point of 30.53°C; 21.31°C and 25.87°C respectively. Temperature generally has a negative effect on cocoa productivity, although it does not have a big impact. However, continuous exposure to temperature will lead to a more harmful threat to cocoa productivity. This research contributes to the use of non-linear regression analysis, especially quadratic regression model in determining climatic factors that influence cocoa productivity in Indonesia, considering that not many studies have used similar model.

Climate Trends and Wheat Yield in Punjab, Pakistan: Assessing the Change and Impact

Climate change has made weather patterns less predictable, making situations more challenging for farmers throughout the production process. This study investigates the impact of climatic variables (maximum and minimum temperature, rainfall, humidity at 8 AM and 5 PM) and fertilizer application on wheat production in Bahawalnagar district, a major wheat producing region of Punjab, Pakistan. The study utilizes the Mann–Kendall and multiple linear regression analysis to check climatic trends and identify the factors influencing wheat yield from 1991 to 2022. The study utilized a regression model to compare actual and predicted wheat yields. The results showed a decreasing trend in rainfall and an increasing trend in both maximum and minimum temperatures during the wheat growing season. Sen’s slope values for maximum temperature (0.037), minimum temperature (0.007), humidity at 8 AM (0.275), and humidity at 5 PM (0.167) indicate the direction and magnitude of trends. The regression model explained about 92% of the variance in the wheat yield. The regression analysis of humidity at both 8 AM (p = 0.001) and 5 PM (p = 0.001) shows a significant positive correlation with wheat yield. Fertilizer use exhibited a significant positive association with wheat yield (β = 9.58). Fertilizer application for wheat crops increased from 112.4 kg/ha in 1991 to 284.3 kg/ha in 2021. The regression model identifies that the average wheat yield loss from 1991 to 2022 is approximately 0.1208 t/ha per year because of the influence of climatic factors. The study findings underscore the importance of the utilization of adaptive agricultural practices that can ensure food security and improve agricultural sustainability in the region.

Influence of climatic factors on the life stages of Aedes mosquitoes and vectorial transmission: A review.

Aedes aegypti and Aedes albopictus are two sympatric mosquito species that compete with each other for resources when their breeding habitats overlap. This study examines what happens when sympatric Aedes aegypti and Aedes albopictus mosquitoes' mate with each other and other species by looking at insemination rates, fecundity, and hatchability rate. We performed controlled mating experiments in laboratory setting, assessing both conspecific and interspecific crosses. We measured insemination rates, egg numbers, and hatching success to examine the reproductive interference dynamics between these two distinct mosquito species. In the context of conspecific mating, it was observed that both female Ae. aegypti and Ae. albopictus exhibited high insemination rates, with percentages of 98% and 94%, respectively. However, interspecific mating exhibited interesting asymmetries: Ae. albopictus males achieved a notable insemination success rate of 28% when mating with Ae. aegypti females, while Ae. aegypti males achieved only 8% insemination success with Ae. albopictus females. Additionally, females that mated with interspecific males had reduced production of viable eggs compared to conspecific mating. Most notably, interspecific mating resulted in the production of infertile eggs, while conspecific mating led to successful hatching. The study reveals that, Ae. aegypti and Ae. albopictus can asymmetrically interfere with each other's reproduction, causing a 'satyr' effect. This understanding of interspecific competition and reproductive interference in these mosquito species could impact their coexistence in shared breeding habitats.

Meta-analysis of the climate change-tourism demand relationship

As climate change urgency intensifies, understanding its impact on destinations and the development of adaptation strategies becomes critical for sustainable tourism. This article, through a meta-analysis of 290 climate change elasticity estimates in tourism from 34 studies, examines the influence of climate factors and tourists’ adaptive behaviours on tourism demand. It also projects the situations countries will face by 2050 under ongoing climate change scenarios. Findings suggest that low- and middle-income economies and Small Island Developing States, despite their minimal carbon contributions, will face significant tourism losses. In contrast, high-income countries might see increased travel demand and lead to more emissions. This will aggravate climatic conditions and inflict greater losses on less-developed communities. This finding exemplifies a vicious cycle of climate injustice, highlighting the disparities in climate-related social costs globally.

Changes in water conservation and possible causes in the Yellow River Basin of China during the recent four decades

As water quality declines and water resources become scarce, water conservation emerges as the central challenge of water resource management and sustainable development in the watershed ecosystem. The Yellow River, known as the “mother river” of China, of which the water conservation function has received significant public attention in the changing environmental conditions. In the study, the InVEST water yield model was utilized to evaluate the spatiotemporal dynamics of water conservation; the MK trend test and Sen’s slope were used to examine the trends of precipitation and water conservation, respectively. Additionally, the response of water conservation to climate, land use, and soil changes during the period 1981–2020 was also discussed. The results showed that under the comprehensive influence of various factors, the water conservation of the YRB showed a decreasing and then increasing trend, which was presumed to be associated with the Grain for Green Project. Water conservation showed an increasing trend in the upstream area of the study area while decreasing in the lower reaches in recent decades. The changes in water conservation function in the YRB resulted from the comprehensive influence of climate factors, soil conditions, and land use types. Besides, woodland and grassland provide the highest water conservation capacity, which initially increased and then decreased with the increase of slope. The spatial analysis emphasized the critical role of water conservation in the Yellow River Basin, particularly highlighting the source area (above Lanzhou Station), the southern tributaries of the Wei River, and the upper reaches of the Yiluo River as significant water conservation zones. These areas should be considered crucial and given priority in regional water resource management and ecological protection efforts. The findings of this study could provide a theoretical foundation for ecological protection and water security in the YRB, which are essential for sustainable development.

Vertical structures and microphysical characteristics of summer precipitation in North China detected by GPM-DPR

The vertical structure and microphysical characteristics of stratiform precipitation (SP) and convective precipitation (CP) in North China are revealed based on the GPM-DPR product during boreal summer of 2014–2021 in this study. Additionally, the differences in precipitation features between the mountain and the plain are investigated. Under the combined influence of climatic factors and local topography, the precipitation amount is larger in the plain than in the mountain while precipitation frequency exhibits an opposite pattern. The proportions of the two precipitation types are similar in the mountain and the plain, with CP contributing to approximately a quarter of total precipitation frequency. In terms of mean intensity, both SP and CP are roughly 20 % more intense in the plain than in the mountain. The greater number of light SPs is a major contributor to higher precipitation frequency in the mountain, while more intense CPs result in larger precipitation amount in the plain. Compared to the mountain, the precipitation system is deeper in the plain, where higher storm top altitudes (STAs) and larger freezing level heights contribute to more intense CPs. Besides, it is observed that for the STA, more intense CPs occur in the plain compared to the mountain. In both the mountain and the plain, the coalescence process is dominant in the low-level layers for heavy (8–20 mm/h) to storm-level (>20 mm/h) CPs. Compared to the mountain, the low-level growth of hydrometeor size and radar reflectivity is more significant in the plain. These findings are important to quantitative precipitation estimation and precipitation prediction in the mountainous region, and can help understand the influence of local topography on precipitation.

Energy Compensation for Crop Growth under Plastic Mulching: Theories, Models, and Limitations

Plastic film mulching (PM) is a useful agronomic means to adapt to the environmental conditions of dryland agriculture and improve crop production. To improve the theoretical framework of PM technology, this study focuses on the interaction between the soil temperature change caused by PM and crop growth. The definition, action mechanism, and simulation of the compensatory effect of PM on growing degree days are introduced to reveal the effect of soil temperature under PM on crop development and growth. Our summary shows that the strength of the warming effect changes with the growth and development of crops, strengthening during the early stage of crop growth and gradually weakening as a crop canopy develops. Generally, the warming effect has a good promotion effect on crop growth, but the crop growth is hampered even with a yield reduction when the increased soil temperature caused by PM exceeds the tolerant temperature for plant growth. Moreover, the compensatory effect of PM could be used to quantify the growth and development of crops under PM and has been widely applied to cotton, corn, winter wheat, and rice. The compensation coefficient is larger in the early stage of crop growth than in the later stage. The compensation coefficient has certain differences for the same crop because of the influence of climate factors, soil moisture content, and soil microtopography. In future research, the theoretical integration of the safety period of PM and the time threshold of the compensatory effect could be theoretically interpreted, and the construction of the compensatory effect module in the crop models will also be an important issue.

Influence of forest age, tree size, and climate factors on biomass and carbon storage allocation in Chinese fir forests

Biomass and carbon allocation among plant organs are influenced by the individual tree's development and climate conditions. Chinese fir forests play an important role in the carbon cycle and climate change mitigation in China. Understanding how forest age, tree size, and climate factors affect biomass and carbon allocation in Chinese fir forests is crucial to fully utilize the carbon sequestration potential. We analyzed the response of Chinese fir biomass allocation fractions (BAFs) and carbon stock allocation fractions (CAFs) to forest age, tree size, and climate factors, utilizing field survey data on biomass of 93 trees in Fujian, Sichuan, Guangxi, and Jiangxi provinces and carbon storage of 40 trees in Fujian, Sichuan, and Guangxi provinces in China. Our results showed that BAFs depend on individual development. In young and middle-aged forests, BAFs were unaffected by diameter at breast height (DBH), whereas branch and root biomass fractions displayed a significant positive correlation with DBH, and stem biomass fraction displayed a negative correlation with DBH in mature forests. Carbon concentration exhibited substantial variation among distinct components and regions. Overall, the carbon concentration of each organ ranked as Guangxi > Sichuan > Fujian. BAFs of dominant trees are almost independent of climatic factors, while suppressed trees will alter their strategies for biomass allocation in response to climate change. Stem biomass fraction exhibited a significant positive correlation with maximum growing season temperature, mean summer temperature, and maximum summer temperature, whereas leaf biomass fraction showed the opposite trend. Under future climate warming, Chinese fir will allocate more biomass to the stem, at the expense of leaf biomass. These findings support the idea that biomass allocation patterns serve as adaptive patterns to address fluctuations in internal and external conditions. The interaction between climate factors and tree size shows promise for predicting trends in forest biomass and carbon accumulation in the context of future climate change.

Spatial-temporal heterogeneity of ecological quality changes across the Qinghai-Tibet Plateau under the influence of climate factors and human activities

Over the last few decades, the ecological quality of the Qinghai–Tibet Plateau (QTP) has significantly changed due to climate warming, humidification, and increasing human activities. Thus, evaluating this region's ecological quality and dominant factors is crucial for sustainable development. In this study, the changes in the ecological quality on the QTP from 2000 to 2020 were evaluated based on aggregated indices and Sen–MK trend analyses, and the dominant factors affecting the ecological quality of the QTP were quantitatively analyzed using decision tree classification. The results revealed that (1) the ecological quality of the QTP exhibited an overall high trend in the east and a low pattern in the west; (2) the ecological quality of the QTP significantly increased from 2000 to 2020, and human activities were the dominant factors causing this change; and (3) the changes in the ecological quality and dominant factors exhibited obvious spatiotemporal heterogeneity. The area with an improved ecological quality occurred mainly in the northern QTP region. It was governed by human activities and precipitation. In contrast, the area with a deteriorated ecological quality occurred largely in the southern QTP region and was dominated by human activities and temperature. The 2000–2010 period was the most significant period of heterogeneity regarding of ecological quality and its driving factors. (4) The change in the ecological quality was mainly affected by the synergistic relationship between human activities and climate change in this region, which encompassed multiple dominant factors. This study provides important information on the spatiotemporal heterogeneity of ecological quality change and its dominant factors on the QTP and offers systematic guidance for the planning and implementation of ecological protection projects.

Dendroclimatology of Araucaria angustifolia: Assessing climatic responses in sites under similar ecological conditions

Dendrochronological studies have increasingly explored tropical and subtropical trees, mainly focusing on their climatic signals. In the neotropics, growth ring width chronologies of Araucaria angustifolia have been developed at several localities in the south of its distribution, in the Atlantic forest biome. However, the signals identified in these studies indicate different patterns of growth response to climate. Understanding the causes of this variability in dendroclimatic signals is important to guide future dendrochronological studies with A. angustifolia. In this work we test the premise that at independent sites, but under similar environmental conditions, chronologies of A. angustifolia exhibit a common growth signal determined by limiting climatic conditions. We developed a new ring width chronology and correlated it with another one already published, both located in Curitibanos municipality, Santa Catarina state, Brazil and with similar climatic, edaphic and vegetational conditions. The chronologies, with reasonable level of internal growth synchrony and sampling effort, showed a common growth signal of moderate magnitude. This common growth pattern between the sites, represented by a regional chronology, showed significant correlations with local climatic variable and with El Niño Southern Oscillation (ENSO), with weak magnitudes. Partial correlations showed that this set of climatic variables was determinant of the common signal between the sites. Our results confirm the validity of the tested premise. Under the conditions studied, the growth response of A. angustifolia to climate is driven by yearly variation in temperature, which operate at different stages of the annual growth cycle and are influenced by ENSO. The low sensitivity of growth to climate is possibly related to the combined influence of multiple climatic factors and/or to moderate growth variability within sites. The multiplicity of climatic factors influencing growth of A. angustifolia trees may also explain some variability of climatic signals reported for with this species.

Global richness patterns of alpine genus Gentiana depend on multiple factors.

Environmental factors impact species richness differently across taxonomic groups, and understanding the geographic patterns and drivers influencing alpine plant richness remains limited. This study compiled global distribution data of 404 species of Gentiana, an alpine genus, and analyzed the relative effects of different environmental factors and several previously proposed models on the variation of Gentiana richness. By evaluating the effects of range size and regions on the relationships between Gentiana richness and environmental factors, we found that all tested environmental factors had weak effects on richness variation for all species and wide-ranging species, while habitat heterogeneity was the best predictor for narrow-ranging species. Habitat heterogeneity was the main driver of richness variation in Europe and Asia, but not in North America. The multiple regression model that included variables for energy, water, seasonality, habitat heterogeneity and past climate change had the highest explanatory power, but it still explained less than 50% of the variation in species richness for all Gentiana species at both global and regional scale, except for Europe. The limited explanatory power of environmental factors in explaining species richness patterns for all species, along with the variations observed among regions, suggest that other factors, such as evolutionary processes and biogeographic history may have also influenced the geographic patterns of Gentiana species richness. In conclusion, our results indicate a limited influence of climate factors on alpine species richness, while habitat heterogeneity, along with its impacts on speciation and dispersal, likely play significant roles in shaping the richness of alpine Gentiana species.