Range Of Climates Research Articles

Environmental characterization and impact of climatic fluctuations on the diversity of extremophilic bacterial communities of a high-altitude seasonal meltwater pond on Ojos del Salado (Dry Andes, Chile)

Earth has unique environments where only microorganisms adapted to extreme conditions can survive. The focus of this study was a high-altitude seasonal meltwater pond on the Altiplano plateau at 5900 m (Dry Andes). The polyextremophilic bacteria of this habitat must adapt to a range of extremities, including cold and dry climate, high UV radiation, and low nutrient availability. A macro-scale analysis was performed to characterize the environment using satellite imagery. To study the composition of bacterial communities, samples were taken from permafrost, water, and sediment of a meltwater pond during three subsequent expedition years under different weather conditions (average, high precipitation, severe drought). The bacterial diversity of the samples was revealed by Illumina MiSeq 16S rRNA gene amplicon sequencing. The results showed that the relative abundance of dominant phyla, such as Pseudomonadota, Bacteroidota, Acidobacteriota, and Verrucomicrobiota varied according to sample types and weather conditions, supported by the satellite environmental state analysis that showed correlations between the availability of snow, water surfaces, and the corresponding surface temperature values. Strong moisture-dependent quantitative changes were detected in the phyla Cyanobacteriota and Actinomycetota. Predominant sequences were linked to orders Chitinophagales, Burkholderiales, Flavobacteriales, and Sphingomonadales, known for their ability to degrade various organic compounds.

On the occurrence of Sorbus tianschanica Rupr. (Rosaceae), a climate relict from Ladakh, Indian Trans Himalaya

ABSTRACT A new distribution record of Sorbus tianschanica Rupr., a tree or shrub native to the temperate northern hemisphere, is reported for Ladakh. Thirty-one individuals of S. tianschanica were seen growing on exposed cliffs and also on shadowed cliff bases in a remote valley in the western Ladakh region of Kargil. A detailed taxonomic description, diagnostic features and notes on the habitat of the species along with its distribution and climatic range in the adjacent phytogeographic regions (Gilgit-Baltistan, Tajikistan, Kyrgyzstan, Kazakhstan and some provinces of China) are provided. Further, information on the species palaeoecology and biogeography has been reviewed, and its conservation significance is discussed. Our findings emphasise the importance of keeping records of local biodiversity up to date. This is critical for implementing global biodiversity policies and meeting conservation goals.

Determination of the continuous grade of a binder in the South African performance grade binder specification

A Performance Grade (PG) Bitumen Specification, SATS-3208 (SATS 2019), was developed in South Africa during the period up to 2019. Since that time a period of implementation has begun on selected projects in South Africa. The implementation activities have included testing of data in accordance with the final anticipated standards. Formulation of a national standard is in the final stages and is expected to be published towards the end of 2024. The PG grade is specified using a high temperature number and a minimum temperature number that indicate the climate range within which a bitumen would be expected to perform. For example, a PG64-22 has a high temperature of 64°C and a minimum temperature of -22°C, from which intermediate and low operating temperatures are derived. A material meeting this grade will always have a performance range which is, ideally, just bigger than the specification grade and this is typically referenced as the continuous grade. A further definition is the difference between the two continuous grade numbers, referenced as the "Useful Temperature Interval" or UTI. As part of this implementation, it is required to determine the continuous grade for bitumen, including for modified binders, to ensure compliance with the specification. The UTI must be equal to or greater than 80°C. This technical note has been developed to demonstrate correct procedure to determine the continuous grade and UTI.

Understanding sediment and carbon accumulation in macrotidal minerogenic saltmarshes for climate resilience

Coastal saltmarshes play an essential role in providing services such as sediment and carbon storage, coastal protection and support for biodiversity. Despite their importance, understanding the factors controlling sediment and carbon accumulation in these minerogenic saltmarshes remains challenging due to their diversity and site-specific characteristics. Understanding the respective role of these drivers is essential for effective coastal management, particularly for mitigating the impacts of climate change. This study evaluates the control of forcing factors on the lateral and vertical morphological evolution and carbon burial rates of three minerogenic saltmarshes located on the French Atlantic coast (Pertuis Charentais region). By focusing on these sites, the study isolates specific factors such as wind and wave exposure, inundation frequency, and sediment availability, while minimizing confounding influences like climate and tidal range. Results reveal significant lateral expansion of saltmarsh boundaries towards the sea across all sites, with the highest rates of progradation observed in the protected areas influenced by geomorphological features such as sand spits and sheltered bay heads. Sediment and mass accumulation rates (SAR; MAR), derived from 210Pb and 137Cs profiles of sediment cores (n = 14), range from 0.48 to 2.22 cm yr−1, among the highest reported globally, with notable variability within and between sites. Inundation frequency and accommodation space explain SAR variability within sites, while sediment availability predominantly determines spatial differences in vertical accumulation rates between sites. Organic carbon burial rates range from 75 to 345 gC m−2 yr−1, and show a strong correlation with SAR (r = 0.9, p < 0.001, n = 13) but no dependence on carbon content or density (r = 0.2, p > 0.05, n = 13). This highlights the role of sediment input in the accumulation and sequestration of carbon by minerogenic saltmarshes. Furthermore, isotopic analysis indicates a marine source dominance in organic carbon sediment. This research provides insights into how different environmental conditions affect saltmarsh morphological evolution and carbon sequestration rates, informing targeted coastal management strategies focused on enhancing ecosystem resilience and climate resilience.

When do contemporary wildfires restore forest structures in the Sierra Nevada?

BackgroundFollowing a century of fire suppression in western North America, managers use forest restoration treatments to reduce fuel loads and reintroduce key processes like fire. However, annual area burned by wildfire frequently outpaces the application of restoration treatments. As this trend continues under climate change, it is essential that we understand the effects of contemporary wildfires on forest ecosystems and the extent to which post-fire structures are meeting common forest restoration objectives. In this study, we used airborne lidar to evaluate fire effects across yellow pine and mixed conifer (YPMC) forests of California’s Sierra Nevada. We quantified the degree to which forest structures in first-entry burned areas (previously unburned since ~ 1900s) and unburned controls aligned with restoration targets derived from contemporary reference sites. We also identified environmental conditions that contributed to more restorative fire effects.ResultsRelative to unburned controls, structural patterns in first-entry burned areas aligned more closely with reference sites. Yet, across all burn severities, first-entry wildfires were only moderately successful at meeting targets for canopy cover (48% total area) and ladder fuels (54% total area), and achieving these targets while also producing tree clump and opening patterns aligning with reference sites was less common (16% total area). Moderate-severity patches had the highest proportion of restorative fire effects (55–64% total area), while low- and high-severity patches were either too dense or too open, respectively. Our models (and publicly-available mapped predictions) indicated a higher probability of restorative effects within 1 km of previous fires, within the mid-upper climate range of the YPMC zone, and under moderate fire intensities (~ 1–2 m flame lengths).ConclusionsFirst-entry wildfires can sometimes restore structural conditions by reducing canopy cover and ladder fuels and increasing structural heterogeneity, especially within moderate-severity patches. However, these initial fires represent just one step toward restoring dry forest ecosystems. Post-fire landscapes will require additional low- to moderate-intensity fires and/or strategic management interventions to fully restore structural conditions. In yet unburned forests, managers could prioritize mechanical treatments at lower elevations, early-season burning at mid to high elevations, and resource objective wildfires in landscapes with mosaics of past wildfires.

Drivers of phenotypic variation and plasticity to drought in populations of a Mediterranean shrub along an environmental gradient

Assessing the factors driving intraspecific phenotypic variation is crucial to understand the evolutionary trajectories of plant populations and predict their vulnerability to climate change. Environmental gradients often lead to phenotypic divergence in functional traits and their plasticity across populations. We studied the entire environmental range of the Mediterranean gypsum endemic shrub Helianthemum squamatum to evaluate the factors underlying quantitative population differentiation and phenotypic plasticity to drought, using a common garden with 16 populations that covered the main geographic and the entire climatic range of the species. Sampling followed a hierarchical approach to assess trait genetic variation within and among four distinct geographical regions. We found high but similar plastic responses across populations, which were consistent with adaptive plasticity to drought, including advanced phenology, more sclerophyllous leaves, higher water use efficiency and larger seeds in dry conditions. Despite these generally similar plastic responses, we found significant population differentiation in quantitative traits, part of which was structured at the regional scale. Such differentiation was not associated with environmental variation, including differences in climate and soil conditions. This suggests that non-adaptive processes might have had a role on genetic differentiation in H. squamatum, likely due to the island-like configuration of gypsum habitats and the lack of effective seed dispersal of the study species. Our results emphasize the role of phenotypic plasticity in adaptive drought response and the importance of considering both adaptive and non-adaptive processes shaping intraspecific phenotypic variation, which is crucial for predicting plant population vulnerability to climate change.

LCA and economic cradle-to-gate analysis on the reuse of a temporary building.

In recent decades, the significant negative environmental impacts of the construction industry have caused a lot of concern, especially from the large number of temporary buildings required for mega projects. Reusing building components can help reduce pollution and preserve resources, but the economic and environmental effects are not well understood. This study has addressed the economic and environmental effects of reusing temporary building elements using life cycle assessment (LCA). The product system and functional unit in the current study is an office building equipment workshop with an area of 80 m2 and the system boundary is from cradle to gate. Life cycle assessment was accomplished using Simapro software and several life cycle assessment methods such as CML-la Baseline, BEES + , and IPCC was used to verify the results. The findings show that reusing disassembled building parts can reduce environmental damage by 79% and environmental damage costs by 77%. These results are important for construction managers seeking to make sustainable decisions that minimize environmental harm. Future research should expand the system boundary to include the entire building life cycle and apply the methodology to a wider range of building types and climates. Developing design guidelines for disassembly and reuse would also help promote sustainable construction practices. Overall, this study provides a robust framework for assessing the environmental and economic impacts of reusing building components, which is crucial for achieving sustainable development in the construction industry.

Geography and associated bioclimatic factors differentially affect leaf phenolics in three ivy species (Hedera L.) across the Iberian Peninsula

The biosynthesis of secondary metabolites in plants, especially that of phenolic compounds, is stimulated to protect against several environmental stress factors such as cold temperatures, drought, and UV-irradiance. As a result, when a species occurs under different climatic conditions, differences in phenolic accumulation are expected across species distribution in response to the environmental cues. However, our understanding of phenolic compounds' natural variation is limited, as most of our knowledge on secondary metabolite biosynthesis stems from experimental studies conducted under controlled conditions. In this study we analyze phenolic content and its relation to climatic and geographic variation in three closely related Hedera species (H. helix, H. hibernica and H. iberica) across their southwestern range limits in the Iberian Peninsula (82 populations, 401 individuals). The Iberian Peninsula concentrates the highest global species richness of Hedera, with the three species sharing range boundaries along the latitudinal and longitudinal climatic gradient of the region. We found that the three species exhibited different climatic and geographic patterns of phenolic content variation in the study area. The phenolic production in H. helix increased with elevation in relation to the decrease of temperature and the increase of temperature contrast, whereas in H. hibernica varies with latitude in relation to summer temperature and precipitation regimes, increasing in areas with no summer drought. In contrast, we did not find any environmental variables associated with phenolic content in H. iberica, likely due to its narrow geographic and climatic range and a higher influence of microclimatic conditions. Although the three Hedera species are closely related, our results suggest that leaf phenolic production may be triggered by different environmental conditions in each species. Our study underscores the species-specific nature of phenolic compounds' role in plant stress response.

Global Health Governance and International Law in India: A Socio-Legal Study

India is a culturally and historically rich nation. India has hosted several ancient civilizations that differed greatly from one another in many aspects of life due to its large geographic expanse, varied climate, and unique environmental conditions. India boasts a vast diversity and cultural ethos that is unmatched in comparison to other regions of the world, encompassing a wide range of faiths, dialects, cuisines, climates, cultures, and social systems. It is a well-established truth that health problems existed wherever there were humans. Given that India is the starting point of early organised communities and historical civilizations, it is evident that healthcare and health were prevalent there long before. Since the beginning of time, historical texts have been filled with references to a wide range of health-related topics. An attempt will be made to conduct a study on court rulings and reports of the Government of India in the proper places in order to support the proposed study and determine how the law pertaining to the right to health is being implemented. Thus, the study's technique, which is an analytical doctrinal approach, has been used.

Additional data on the ongoing naturalization of the non-native woody plant Duranta erecta ( Verbenaceae) in Sicily, Italy

We recorded the occurrence of Duranta erecta L. in the Aeolian Islands (Sicily, Italy), where it currently behaves as a casual alien. At the global scale, however, this woody species has shown highly invasive behaviour in different island ecosystems. On the basis of this evidence, we have investigated which ecological and biological traits may have allowed its establishment and spread, and could trigger its further expansion in the Aeolian Islands in the near future. Several factors seem to have favoured its success on a global scale, such as the wide edaphic and climatic range, the tolerance to anthropogenic disturbance, and the production of toxic metabolites that protect it from herbivore browsing and from competition with other plants. The study of the organisms that perform pollination and seed dispersal is probably the key to understanding the local naturalization of this plant, introduced about three centuries ago in Europe and the Mediterranean, here discussed in detail for the first time.

Spatiotemporal analysis of landscape dynamics and their use as input for the design of a habitat suitability index: A case study of Oryctolagus cuniculus in a Mediterranean region

The connectivity of landscapes is increasingly threatened by urban sprawl, which leads to the fragmentation of habitats and thus endangers the species that live there. To address this situation, landscape dynamics in the literature have mostly been analyzed using predefined land cover classes, which were then not used to assess habitat suitability, but instead relied on physical variables. As a bridge between both aspects, this study aimed to model the spatiotemporal patterns of landscape fragmentation by analyzing the landscape metrics associated with four land cover groups classified according to their naturalness. Landscape metrics were then combined with a range of terrain, climate and proximity variables to develop a Habitat Suitability Index (HSI) for terrestrial animal species. The proposed methodology was tested using a case study in the Mediterranean region of the Valencian Community (Spain): landscape dynamics were assessed over the period 1992–2015, while the HSI was tested with the European rabbit (Oryctolagus cuniculus) as the target species. The results obtained in terms of landscape dynamics showed a growing presence of artificial surfaces at the expense of fewer transformed areas, which became progressively fragmented over time. Moreover, the results of the developed HSI were highly concordant with observations of rabbit abundance in the region, based in particular on variables related to the temperature in the area and the patch shape in the preferred habitats of this species. These outputs can be used to support the implementation of habitat restoration strategies aimed at increasing ecological connectivity through measures such as wildlife crossings.

Comparative genomics and stable isotope analysis reveal the saprotrophic-pathogenic lifestyle of a neotropical fungus.

This is the first genomic description for Phellinotus piptadeniae. This basidiomycete is found across a broad range of climates and ecosystems in South America, including regions threatened by extensive agriculture. This fungus is also relevant considering its pathotrophic-saprotrophic association with Piptadenia goanocantha, which we began to understand with these new results that locate this species among biotrophic and necrotrophic fungi.

Taxonomic diversity and environmental tolerance of cultivable extremophilic bacteria from a high-altitude meltwater pond on Ojos del Salado (Chile).

Earth harbors unique environments where only microorganisms adapted to extreme conditions, known as extremophiles, can survive. This study focused on a high-altitude meltwater pond, located in the Puna de Atacama, Dry Andes. The extremophilic bacteria of this habitat must adapt to a range of extremities, including cold and dry climate, high UV radiation, high daily temperature fluctuations, low-nutrient availability, and negative water balance. This study aimed to explore the taxonomic diversity of cultivable extremophilic bacteria from sediment samples of a desiccated, high-altitude, meltwater pond using media with different organic matter contents and different incubation temperatures. Based on the 16S rRNA gene sequence analysis, the isolates were identified as members of the phyla Actinobacteria, Proteobacteria, and Firmicutes. The most abundant genera were Arthrobacter and Pseudoarthrobacter. The isolates had oligocarbophilic and psychrotrophic properties, suggesting that they have adapted to the extreme environmental parameters of their natural habitats. The results indicate a positive correlation between nutrient concentration and temperature tolerance.

Factors driving microbial biomass and necromass relationships display ecosystem‐dependent responses

AbstractMicroorganisms help govern soil organic carbon (SOC) turnover and accumulation. Whilst it is increasingly clear that microbial necromass is a precursor of SOC formation, the relationship between living microorganisms, necromass turnover and SOC persistence remains elusive. In this study, we used phospholipid fatty acids and amino sugars to quantify living versus dead microbial carbon concentrations and evaluated the utility of each pool as an indicator of SOC persistence across a range of climates (low‐, mid‐ and high‐latitude sites) and ecotypes (old‐growth forests vs. managed croplands). We found that microbial necromass was higher in forest than in cropland soils and was positively correlated with soil moisture, SOC and total nitrogen (TN). However, the flow of microbial biomass into necromass and SOC was decoupled in forest sites, likely because the high soil SOC/TN ratio accelerated necromass turnover and recycling by living microorganisms. In contrast, microbial biomass and necromass pools were tightly coupled in croplands and influenced by multiple environmental and biological factors (e.g., necromass concentrations exhibited greater variability in soils with more bacteria than fungi, and those with more gram‐positive than gram‐negative taxa). Contrasting our expectations, the proportion of microbially‐derived necromass in SOC was decoupled from soil properties and microbial biomass in both ecotypes. Whilst SOC and pH appear to be universal drivers of necromass cycling, feedbacks between living biomass, necromass and SOC are shaped by local factors. Our results contribute to ecological theory by highlighting the environmental and biological factors underpinning SOC formation and turnover that can be used to inform land‐management practices that optimize below‐ground carbon sequestration.

Local climate change velocities and evolutionary history explain multidirectional range shifts in a North American butterfly assemblage.

Species are often expected to shift their distributions either poleward or upslope to evade warming climates and colonise new suitable climatic niches. However, from 18-years of fixed transect monitoring data on 88 species of butterfly in the midwestern United States, we show that butterflies are shifting their centroids in all directions, except towards regions that are warming the fastest (southeast). Butterflies shifted their centroids at a mean rate of 4.87 km year-1. The rate of centroid shift was significantly associated with local climate change velocity (temperature by precipitation interaction), but not with mean climate change velocity throughout the species' ranges. Species tended to shift their centroids at a faster rate towards regions that are warming at slower velocities but increasing in precipitation velocity. Surprisingly, species' thermal niche breadth (range of climates butterflies experience throughout their distribution) and wingspan (often used as metric for dispersal capability) were not correlated with the rate at which species shifted their ranges. We observed high phylogenetic signal in the direction species shifted their centroids. However, we found no phylogenetic signal in the rate species shifted their centroids, suggesting less conserved processes determine the rate of range shift than the direction species shift their ranges. This research shows important signatures of multidirectional range shifts (latitudinal and longitudinal) and uniquely shows that local climate change velocities are more important in driving range shifts than the mean climate change velocity throughout a species' entire range.

Symbionts out of sync: Decoupled physiological responses are widespread and ecologically important in lichen associations.

A core vulnerability in symbioses is the need for coordination between the symbiotic partners, which are often assumed to be closely physiologically integrated. We critically re-examine this assumed integration between symbionts in lichen symbioses, recovering a long overlooked yet fundamental physiological asymmetry in carbon balance. We examine the physiological, ecological, and transcriptional basis of this asymmetry in the lichen Evernia mesomorpha. This carbon balance asymmetry depends on hydration source and aligns with climatic range limits. Differences in gene expression across the E. mesomorpha symbiosis suggest that the physiologies of the primary lichen symbionts are decoupled. Furthermore, we use gas exchange data to show that asymmetries in carbon balance are widespread and common across evolutionarily disparate lichen associations. Using carbon balance asymmetry as an example, we provide evidence for the wide-ranging importance of physiological asymmetries in symbioses.

Eocene–Oligocene vegetation and climate changes in southeastern Brazil

The Eocene–Oligocene Transition (EOT) marks the onset of a major phase of global cooling with significant consequences to the vegetation worldwide. Here, we present palynological analyses from a site in southern São Paulo basin, southeastern Brazil (23.67°S; 46.58°W). An Oligocene age was constrained by the abundance of Dacrydiumites florinii and Podocarpidites spp., alongside the presence of taxa such as Cicatrocosisporites dorogensis and Polypodiisporites usmensis. Autochthonous elements including Paleoazolla, Corsinipollenites spp., Monoporopollenites annulatus, and Zygnemataceae algae spores are indicative of a low-energy freshwater depositional environment. In addition, we performed a comparison of Eocene and Oligocene temperature and precipitation estimates from records in southeastern Brazil using the weighted Mutual Climate Range approach. Results support global trends with a cooling of ca. 3–4 °C from the Eocene to the Oligocene accompanied by slightly drier regional conditions. Oligocene environmental changes drove a vegetation turnover by local extinction of warm-tropical taxa or a significant retreat of species unable to stand comparatively colder and drier climates under lower CO2atm concentrations. Our data are consistent with previous estimates and verify the impact of global cooling on the vegetation of mid-low latitudes of the Southern Hemisphere.

Demonstrating a Hybrid Machine Learning Approach for Snow Characteristic Estimation Throughout the Western United States

AbstractSnow is a critical component of global climate and provides water resources to over 1 billion people worldwide. Yet current measurement methods and modeling techniques lack the ability to fully capture snow characteristics such as snow water equivalent (SWE) and density across variable landscapes. In recent years, physics‐informed machine learning (ML) methods have demonstrated promise for combining data‐driven learning and physical information. However, this capability has not been widely explored within snow hydrology. Here, we develop a “hybrid” model that applies ML informed by outputs from a physical model and assess whether it provides more accurate estimations of SWE and snow density. We trained and evaluated models at 49 SNOw TELemetry locations spanning a range of snow climates in the western US using 9 years of daily data. The research addressed two questions. In the first, the performance of the hybrid model was compared against a plain neural network (long short‐term memory, Long‐Short Term Memory), a high‐quality physical model, and a statistical snow density model. The second question focused on how regionally trained hybrid models compared to a westwide model as well as their transferability between multiple snow regions. The results showed that combining physical information and ML reduced SWE Root Mean Square Error by 35% compared to a physical model and 51% compared to a neural network. Additionally, regional training only provided minimal benefits compared with a westwide model. These findings indicate that a hybrid approach can yield more accurate snowpack characterization than either physical snow models or ML alone.

Inundation dynamics in seasonally dry floodplain forests in southeastern Brazil

AbstractFloodplains are one of the most threatened ecosystems. Even though the vegetation composition in floodplain forests is expected to reflect the variation in groundwater levels and flood duration and frequency, there is little field data on the inundation dynamics (e.g., the variability in flood duration and flood frequency), especially for the understudied seasonally dry tropics. This limits our understanding of these ecosystems and the mechanisms that cause the flooding. We, therefore, investigated six floodplain forests in the state of Minas Gerais in Brazil for 1.5 years (two wet seasons): Capivari, Jacaré, and Aiuruoca in the Rio Grande basin, and Jequitaí, Verde Grande, and Carinhanha in the São Francisco basin. These locations span a range of climates (humid subtropical to seasonal tropical) and biomes (Atlantic forest to Caatinga). At each location, we continuously measured water levels in five geomorphologically distinct eco‐units: marginal levee, lower terrace, higher terrace, lower plain, and higher plain, providing a unique hydrological dataset for these understudied regions. The levees and terraces were flooded for longer periods than the plains. Inundation of the terraces lasted around 40 days per year. The levees in the Rio Grande basin were flooded for shorter durations. In the São Francisco basin, the flooding of the levees lasted longer and the water level regime of the levees was more similar to that of the terraces. In the Rio Grande basin, flooding was most likely caused by rising groundwater levels (i.e., “flow pulse”) and flood pulses that caused overbank flooding. In the São Francisco basin, inundation was most likely caused by overbank flooding (i.e., “flood pulse”). These findings highlight the large variation in inundation dynamics across floodplain forests and are relevant to predict the impacts of changes in the flood regime due to climate change and other anthropogenic changes on floodplain forest functioning.

Botany of the Valley of Flowers National Park and its Environs

The Valley of Flowers National Park is in the Garhwal Himalayas and this paper provides a list of plant species found there with their flowering time, altitude range of distribution, habit vegetation, climate and topography. The rare plants deserving conservation have also been listed.