Global Change Scenarios Research Articles

Beyond resource limitation: an expanded test of the niche dimension hypothesis for multiple types of niche axes.

The niche dimension hypothesis predicts that more species can coexist given a greater number of niche axes along which they partition the environment. Although this hypothesis has been broadly supported by nutrient enrichment experiments, its applicability to other ecological factors, such as natural enemies and abiotic stresses, has not been vigorously tested. Here, we examined the generality of the niche dimension hypothesis by experimentally manipulating both resource and non-resource niche dimensions-nitrogen limitation, pathogens and low-temperature stress-in a Tibetan alpine meadow. We found that decreases in niche dimensions led to a significant reduction in species richness, consistent with results from nutrient addition studies. However, different niche variables uniquely affected the plant communities. While nitrogen had largest effects on both community biomass and species richness, pathogens and low-temperature stress, in combination with nitrogen, had synergistic effects on them. Our results provide direct evidence demonstrating that both resource and non-resource niche dimensions can influence species coexistence. These findings suggest that other non-resource factors need to be taken into consideration to better predict the community assembly and control over biodiversity, particularly under the future multifaceted global change scenarios.

New localities and distribution models inform the conservation status of the endangered lizard Anolis guamuhaya (Squamata: Dactyloidae) in central Cuba

New localities and distribution models inform the conservation status of the endangered lizard Anolis guamuhaya (Squamata: Dactyloidae) from central Cuba. Anolis guamuhaya is known from seven localities restricted to the Guamuhaya Massif in central Cuba and is always associated with mountane ecosystems above 300 m a.s.l. Previous evaluations of the conservation status of the species based on the estimated number of mature individuals have categorized the anole as Endangered. Eight new records of A. guamuhaya are provided here. These double the number of known localities, and two represent the first records of the species in lowland areas, apart from the Guamuhaya Massif. The new records extend the elevational range of the species from 15 m to above 1000 m. We used ecological niche modeling based on all of the locality records, along with what we considered the most appropriate IUCN criteria according to the available information (Criterion B) to reevaluate the conservation status of the species. These new records of A. guamuhaya increase its area of occupancy up to a total of 60 km2 , and its extent of occurrence up to 648 km2 . Despite this increase in geographic range, the species meets the IUCN criteria in the category of Endangered. We used ecological niche modeling to predict possible trends for the species under differing scenarios of global climate change, all of which portend a drastic reduction in area climatically suitable for A. guamuhaya.

Eutrophication, biodiversity loss, and species invasions modify the relationship between host and parasite richness during host community assembly

Host and parasite richness are generally positively correlated, but the stability of this relationship in response to global change remains poorly understood. Rapidly changing biotic and abiotic conditions can alter host community assembly, which in turn, can alter parasite transmission. Consequently, if the relationship between host and parasite richness is sensitive to parasite transmission, then changes in host composition under various global change scenarios could strengthen or weaken the relationship between host and parasite richness. To test the hypothesis that host community assembly can alter the relationship between host and parasite richness in response to global change, we experimentally crossed host diversity (biodiversity loss) and resource supply to hosts (eutrophication), then allowed communities to assemble. As previously shown, initial host diversity and resource supply determined the trajectory of host community assembly, altering post-assembly host species richness, richness-independent host phylogenetic diversity, and colonization by exotic host species. Overall, host richness predicted parasite richness, and as predicted, this effect was moderated by exotic abundance-communities dominated by exotic species exhibited a stronger positive relationship between post-assembly host and parasite richness. Ultimately, these results suggest that, by modulating parasite transmission, community assembly can modify the relationship between host and parasite richness. These results thus provide a novel mechanism to explain how global environmental change can generate contingencies in a fundamental ecological relationship-the positive relationship between host and parasite richness.

Plasticity of adult coralline algae to prolonged increased temperature and pCO2 exposure but reduced survival in their first generation.

Crustose coralline algae (CCA) are vital to coral reefs worldwide, providing structural integrity and inducing the settlement of important invertebrate larvae. CCA are known to be impacted by changes in their environment, both during early development and adulthood. However, long-term studies on either life history stage are lacking in the literature, therefore not allowing time to explore the acclimatory or potential adaptive responses of CCA to future global change scenarios. Here, we exposed a widely distributed, slow growing, species of CCA, Sporolithon cf. durum, to elevated temperature and pCO2 for five months and their first set of offspring (F1) for eleven weeks. Survival, reproductive output, and metabolic rate were measured in adult S. cf. durum, and survival and growth were measured in the F1 generation. Adult S. cf. durum experienced 0% mortality across treatments and reduced their O2 production after five months exposure to global stressors, indicating a possible expression of plasticity. In contrast, the combined stressors of elevated temperature and pCO2 resulted in 50% higher mortality and 61% lower growth on germlings. On the other hand, under the independent elevated pCO2 treatment, germling growth was higher than all other treatments. These results show the robustness and plasticity of S. cf. durum adults, indicating the potential for them to acclimate to increased temperature and pCO2. However, the germlings of this species are highly sensitive to global stressors and this could negatively impact this species in future oceans, and ultimately the structure and stability of coral reefs.

The gaseous gastrointestinal tract of a seawater teleost, the English sole (Parophrys vetulus)

There has been considerable recent progress in understanding the respiratory physiology of the gastrointestinal tract (GIT) in teleosts, but the respiratory conditions inside the GIT remain largely unknown, particularly the luminal PCO2 and PO2 levels. The GIT of seawater teleosts is of special interest due to its additional function of water absorption linked to HCO3− secretion, a process that may raise luminal PCO2 levels. Direct measurements of GIT PCO2 and PO2 using micro-optodes in the English sole (Parophrys vetulus; anaesthetized, artificially ventilated, 10–12 °C) revealed extreme luminal gas levels. Luminal PCO2 was 14–17 mmHg in the stomach and intestinal segments of fasted sole, considerably higher than arterial blood levels of 5 mmHg. Moreover, feeding, which raised intestinal HCO3− concentration, also raised luminal PCO2 to 34–50 mmHg. All these values were higher than comparable measurements in freshwater teleosts, and also greater than environmental CO2 levels of concern in aquaculture or global change scenarios. The PCO2 values in subintestinal vein blood draining the GIT of fed fish (28 mmHg) suggested some degree of equilibration with high luminal PCO2, whereas subintestinal vein PO2 levels were relatively low (9 mmHg). All luminal sections of the GIT were virtually anoxic (PO2 ≤ 0.3 mmHg), in both fasted and fed animals, a novel finding in teleosts.

Prioritizing landscape connectivity of a tropical forest biodiversity hotspot in global change scenario

The probability that a propagule reaches, establishes and persists in a certain site is affected by the distance and quality of the environment. Fragmented landscapes promote the isolation of forests surrounded by a matrix that hinders or impedes the movement of species, affecting their distribution and threatening their conservation. Studies of landscape connectivity are essential to provide information for ecological conservation planning. Based on the classification of the landcover of the Rio Doce Basin - RDB and on the circuit theory, we used a habitat / non-habitat approach to assess the connectivity of the RDB to tree species. We built six resistance surface models based on habitat and non-habitat areas, using the GIS plug-in and Linkage Mapper to generate least cost paths maps. Three models explained the Jaccard similarity index matrix of 78 fragments used as a proxy of connectivity to test the models by GLMs, and one out the three was the simplest and most parsimonious. The map generated by the chosen model showed that the RDB is very fragmented but still has well-connected regions. The west to northwestern and southeastern portions of the RDB are well-connected and demand conservation of remaining fragments as well as the creation of reserves, while the center-north, east, and the far southwest of the basin are regions with greater resistance to connectivity as a result of anthropic pressures that reduced and fragmented the forests, requiring intervention through restoration projects to re-establish landscape connectivity.

110 - Emerging adults – a challenge for an integrated psychosomatic approach

There has been considerable recent progress in understanding the respiratory physiology of the gastrointestinal tract (GIT) in teleosts, but the respiratory conditions inside the GIT remain largely unknown, particularly the luminal PCO2 and PO2 levels. The GIT of seawater teleosts is of special interest due to its additional function of water absorption linked to HCO3− secretion, a process that may raise luminal PCO2 levels. Direct measurements of GIT PCO2 and PO2 using micro-optodes in the English sole (Parophrys vetulus; anaesthetized, artificially ventilated, 10–12 °C) revealed extreme luminal gas levels. Luminal PCO2 was 14–17 mmHg in the stomach and intestinal segments of fasted sole, considerably higher than arterial blood levels of 5 mmHg. Moreover, feeding, which raised intestinal HCO3− concentration, also raised luminal PCO2 to 34–50 mmHg. All these values were higher than comparable measurements in freshwater teleosts, and also greater than environmental CO2 levels of concern in aquaculture or global change scenarios. The PCO2 values in subintestinal vein blood draining the GIT of fed fish (28 mmHg) suggested some degree of equilibration with high luminal PCO2, whereas subintestinal vein PO2 levels were relatively low (9 mmHg). All luminal sections of the GIT were virtually anoxic (PO2 ≤ 0.3 mmHg), in both fasted and fed animals, a novel finding in teleosts.

Assessment of Coastal Inundation due to Storm Surge under Future Sea-Level Rise Conditions

Kim, Y.H., 2020. Assessment of coastal inundation due to storm surge under future sea-level rise condition. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 845–849. Coconut Creek (Florida), ISSN 0749-0208.Coastal communities, transportation systems, and energy infrastructures will be at increasing risk of impact from the extreme events like storm surge. Coastal areas are at risk for worse inundation in the near future due to coupled effects of sea-level rise and surge under the future global climate change scenarios. In order to assess the impact of coastal inundation due to the combined effect of sea-level rise and tropical storms, Sea, Lake and Overland Surge from Hurricanes (SLOSH) model was implemented to coastal areas of Korea. SLOSH calculates water level from depth-integrated, quasi-linear, shallow-water equations. In this study, a new developed high-resolution hyperbolic mesh grid was applied to the Korean peninsula. The minimum and maximum grid size is 321 m in coastal regions and ∼18 km in offshore areas, respectively. A total of 60 representative potential storm tracks were developed based on preselected four historic storm tracks in the study area. Each storm tracks were assumed to be 2 different strength, implying each 50 and 100-yr return frequency level. Five different sea-level rise scenario were applied on the basis of the recent IPCC report: 0, 34.1, 65.0, 83.8, and 98.0 cm above the present sea level. Thus, a total of 600 scenarios (= 5 sea levels X 2 strength X 60 storm tracks) were simulated, and Maximum Envelop Of Water (MEOW) and Maximum Of Maximum (MOM) were calculated for each water level case. The results show that the rise of sea level induces higher storm surge and the increasing trend is not linear. For instance, the case with 98 cm sea-level rise above the current sea level show about 1.5-2.5 m increase of storm surge. Also, the results of storm surge (i.e., MOM) were applied to local topography data, which estimate inundation depth for each cell. As expected, the case of present sea level depicts lowest inundation and it increase with the range of sea level rise. Also, the area of inundation is smallest in the case of present sea level, and more sea level rise results in larger area of inundation.

Ocean acidification, hypoxia and warming impair digestive parameters of marine mussels

Global change and anthropogenic activities have driven marine environment changes dramatically during the past century, and hypoxia, acidification and warming have received much attention recently. Yet, the interactive effects among these stressors on marine organisms are extremely complex and not accurately clarified. Here, we evaluated the combined effects of low dissolved oxygen (DO), low pH and warming on the digestive enzyme activities of the mussel Mytilus coruscus. In this experiment, mussels were exposed to eight treatments, including two degrees of pH (8.1, 7.7), DO (6, 2 mg/l) and temperature (30 °C and 20 °C) for 30 days. Amylase (AMS), lipase (LPS), trypsin (TRY), trehalase (TREH) and lysozyme (LZM) activities were measured in the digestive glands of mussels. All the tested stress conditions showed significant effects on the enzymatic activities. AMS, LPS, TRY, TREH showed throughout decreased trend in their activities due to low pH, low DO, increased temperature and different combinations of these three stressors with time but LZM showed increased and then decreased trend in their activities. Hypoxia and warming showed almost similar effects on the enzymatic activities. PCA showed a positive correlation among all measured biochemical parameters. Therefore, the fitness of mussel is likely impaired by such marine environmental changes and their population may be affected under the global change scenarios.

CRISPR-Cas9 mediated genome editing of drought and salt tolerance (OsDST) gene in indica mega rice cultivar MTU1010.

Development of abiotic stress tolerant rice cultivars is necessary for sustainable rice production under the scenario of global climate change, dwindling fresh water resources and increase in salt affected areas. Several genes from rice have been functionally validated by using EMS mutants and transgenics. Often, many ofthese desirable alleles are not available indica rice which is mainly cultivated, and where available, introgression of these alleles into elite cultivars is a time and labour intensive process, in addition to the potential introgression of non-desirable genes due to linkage. CRISPR-Cas technology helps development of elite cultivars with desirable alleles by precision gene editing. Hence, this study was carried out to create mutant alleles of drought and salt tolerance (DST) gene by using CRISPR-Cas9 gene editing in indica rice cv. MTU1010. We used two different gRNAs to target regions of DST protein that might be involved in protein-protein interaction and successfully generated different mutant alleles of DST gene. We selected homozygous dst mutant with 366bp deletion between the two gRNAs for phenotypic analysis. This 366bp deletion led to the deletion of amino acid residues from 184 to 305 in frame, and hence the mutant was named as dst ∆184-305 . The dst ∆184-305 mutation induced by CRISPR-Cas9 method in DST gene in indica rice cv. MTU1010 phenocopied EMS-induced dst (N69D) mutation reported earlier in japonica cultivar. The dst ∆184-305 mutant produced leaves with broader width and reduced stomatal density, and thus enhanced leaf water retention under dehydration stress. Our study showed that the reduction in stomatal density in loss of function mutants of dst is, at least, in part due to downregulation of stomatal developmental genes SPCH1, MUTE and ICE1. The Cas9-free dst ∆184-305 mutant exhibited moderate level tolerance to osmotic stress and high level of salt stress in seedling stage. Thus, dst mutant alleles generated in this study will be useful for improving drought and salt tolerance and grain yield in indica rice cultivars.

Impact of oysters as top predators on microbial food web dynamics: a modelling approach with parameter optimisation

Aquaculture is becoming a relevant and productive source of seafood, and production is expected to double in the near future. However, bivalve activities can significantly impact coastal ecosystem functioning. To study the direct and indirect impacts of oysters on the microbial food web, a 0D biogeochemical modelling approach was adopted. The model was adjusted by parameter optimisation, assimilating data from several mesocosm observations of concentrations of nitrate, phosphate, silicate, dissolved organic carbon, chlorophyll, and bacterial biomass. The optimisation method provided a set of optimal parameters to fit the experimental observations of ‘control’ (i.e. natural water without oysters) and ‘oyster’ (i.e. natural water with oysters) mesocosms. The modelling results showed good accordance with the experimental observations, suggesting that the oysters directly reduced phytoplankton community biomass, thus constraining the ecosystem to a more heterotrophic state. Oysters also reduced competition between bacteria and phytoplankton for nutrient uptake, favouring higher bacterial biomass than in the control experiment. Additionally, the presence of oysters strongly increased large micro-zooplankton biomass (50-200 µm; mainly ciliates and large flagellates). This was a consequence of bacterivory by small zooplankton (5-50 µm; mostly flagellates and small ciliates), providing a trophic link between bacteria and larger zooplankton. In conclusion, parameter optimisation showed good capacity to manage experimental data in order to build a more realistic model. Such models, in connection with future developments in aquaculture and global change scenarios, could be a promising tool for exploited ecosystem management and testing different environmental scenarios.

Nitrogen Tax and Set-Aside as Greenhouse Gas Abatement Policies Under Global Change Scenarios: A Case Study for Germany

The ambitious climate policy objectives of the COP21 agreement require the design and the implementation of effective and efficient policy instruments. The effectiveness and efficiency of agricultural abatement options depend on regional climate and natural conditions, changes in the global economy, global agricultural markets and regional agricultural production. Thus, the assessment of abatement options requires consideration of the global scale, the market scale and the regional producer scale. We investigate two abatement options discussed controversially in literature. Both have been partially applied to reduce environmental pollution from agriculture: a tax on nitrogen and the obligatory set-aside of agricultural land. Our study provides an assessment of the ecological effectiveness and the economic efficiency of both abatement options under different global scenarios. In our policy analysis we combine three applied policy simulation models to develop an integrated economic model framework. This model framework considers the global, the national and the regional scale and consists of the global general equilibrium model DART-BIO, the partial-equilibrium model CAPRI and the regional supply model RAUMIS. In the different global scenarios, the results show that both abatement options create relatively high marginal abatement costs and that the maximally reached abated greenhouse gas emissions represent only 15% of the quantity required to fulfill the policy targets. Compared to the obligatory set-aside option, the nitrogen tax is in both scenarios the more efficient policy. With respect to impacts on production and environment, a nitrogen tax is less forecastable than the obligatory set-aside option. Our study illustrates the relevance of considering global economic and market change in the assessment of producer-targeting environmental policies.

Strategies for Improving Streetscape Character in the Street Precinct of Ashoka Road, Mysore City

Streets in heritage cities are vital elements of public realm system and become a showcase for many celebrations. They not only function as pathways for movement of vehicles, pedestrians, cyclists supporting many societal and occupational activities, but they serve as the places of congregation as well. In India the streets are inherently a place where people meet, congregate, celebrate and also carry business. Each community has its own distinct occasions during which streets becomes the logical setting for people to gather and celebrate. In case of historic streetscapes, they are the carters of histories, with immeasurable evidence about the past events. The city of Mysore has many traditional streetscapes in the historic core exhibiting not only enormous architectural heritage but also has cultural significance. Ashoka Street Precinct, which was historically associated with cultural celebrations like Mysore Dasara during which the spectacular procession took place is situated in the heart of the city. With the shift of these celebrations to an alternative path, the street seems to be losing its’ heritage character and glory, though it is associated with many heritages building and precincts, and due recognition. Hence, it needs to be assessed with respect to the character and the physical quality in order to address the street precincts through the course of dereliction and transformation under the scenario of global change which is the inevitable occurrence everywhere. The paper explores the connection and disconnection between the old and the new and examines the process of physical transformation of Ashoka road precinct from being as a cultural street to a commercial street. The study is based on field work, observations, photo documentation and visual assessment. The streetscape analysis, issues and strategies including the measures proposed would aid the authority in formulation and implementation of streetscape guidelines resulting in improving of heritage character of the street precinct.

Discrepancy in the responses of diatom diversity to indirect and direct human activities in lakes of the southeastern Tibetan Plateau, China

Abstract Both global warming and human impacts are inimical to the maintenance of biodiversity across the planet. Although there is some consensus regarding the probable responses of biodiversity changes under different global change scenarios, the factors controlling biodiversity on regional scales are unclear. Using surveys of lake-bed surface sediments and an analysis of diatoms from six lake cores across 116 lakes in the southeastern Tibetan Plateau of China, we investigated (i) changes in diatom richness and (ii) β diversity and its components at various spatial and temporal scales. β diversity partitioning revealed that the most important factor affecting changes in diatom communities was species turnover across both spatial and temporal scales. This finding indicates that conservation planning requires a regional approach that focuses on multiple lake systems. Temporal changes in the trend of β diversity were shown to result from changes in nestedness components. The results showed that climate warming and indirect human impacts caused the decline of species nestedness, thereby increasing biodiversity, while the intensification of direct human activities caused species nestedness to rise, resulting in concomitant loss of biodiversity. Since nestedness is often related to ordered species gain/loss dynamics, the results suggest that species gain slows down in lakes affected indirectly by human activities, while species loss accelerates in lakes subjected to direct human impacts. Thus, we predict that species richness will continue to decline across this vast region in the future.

Variation characteristics of NDVI and its response to climatic change in the growing season of Changbai Mountain Nature Reserve during 2001 and 2018

To understand the dynamics of temperate forest in Northeast Asia and its response to climate change under the scenario of global change, we examined the temporal and spatial changes of normalized difference vegetation index (NDVI) and their correlation with temperature and precipitation of Changbai Mountain Nature Reserve in the growing season during 2001 and 2018, based on the remote sensing database of MODIS with a resolution of 250 m, land surface temperature data with a resolution of 1 km and meteorological data in the studied and surrounding area. The results showed that, in the growing season of 2001-2018, the averaged NDVI value of the study area was 0.711. Vegetation coverage was relatively high, increasing with a rate of 0.0025·a-1. The temperature showed an extremely significantly increasing trend (0.032 ℃·a-1), the rate of which was higher than that at global level. Precipitation also showed a significantly increasing trend (5.54 mm·a-1) with increased interannual variation. Spatially, NDVI generally was higher in the northwest and decreased with elevation. During the study period, the area with increased NDVI accounted for 46.2%, mainly concentrated in the north and south central high-altitude areas, while 53.8% of total area remained unchanged or slightly decrease. NDVI of the study area was mainly affected by temperature. At the annual scale, NDVI and land surface temperature were positively correlated, with 90.2% presented positive correlation and 43.6% significantly correlated. At the monthly scale, the impact of temperature on NDVI was more significant at the beginning and the end of growing season.

Assessing the effects of in vitro imposed water stress on pineapple growth in relation to biochemical stress indicators using polynomial regression analysis

Knowing the mechanisms that operate under water stress in commercial crops, particularly those that can affect productivity, such as phenolic or cell wall metabolism, is becoming increasingly important in a scenario of global climate change. However, our understanding of how to analyse statistically the relationships between these commonly used biochemical markers of water stress and growth in crops like pineapple, needs to be improved. In the present work, we have addressed the question of whether polynomial regression analysis can be used to describe the influence of selected plant metabolites (chlorophylls, carotenoids, phenolics and aldehydes) on shoot biomass, in response to a mannitol-induced water stress in temporary immersion bioreactors (TIBs). Polynomial regression analysis has been applied to investigate plant stress responses in many species but is very seldom used in in vitro screening studies. Here, the relationship between biochemical indicators (x; independent variable) and shoot growth (y; dependent variable) has been characterised, with y modelled as an nth degree polynomial in x. This statistical approach accommodated for the non-linear (curvilinear) relationships between variables, and the results showed that shoot biomass was negatively, and significantly correlated with soluble phenolics, cell wall-linked phenolics and other aldehydes (characterised by “High” R2 values).

Increased soil moisture aggravated the competitive effects of the invasive tree Rhus typhina on the native tree Cotinus coggygria

BackgroundInvasive exotic species have caused significant problems, and the effects of extreme precipitation and drought, which might occur more frequently under the global climate change scenarios, on interspecific relationship between invasive and native species remain unclear.ResultsWe conducted a greenhouse experiment with three soil water levels (30–40%, 50–60%, and 70–80% of field capacity) and two cultivation treatments (monoculture pots, one seedling of either species and mixture pots, one seedling of each species) to investigate soil water content effects on the relationship between invasive Rhus typhina and native Cotinus coggygria. Rhus typhina had lower height but bigger crown area than C. coggygria in the monoculture treatment. Rhus typhina had higher height, bigger crown area and total biomass than C. coggygria in the mixture treatment. Drought decreased the growth parameters, total chlorophyll concentration, and leaf biomass, but did not change gas exchange and other biomass parameters in R. typhina. The growth parameters, leaf area index, biomass parameters, total chlorophyll concentration, and net photosynthetic rate of C. coggygria decreased under drought conditions. The log response ratio (lnRR), calculated as ln (total biomass of a target plant grown in monoculture/total biomass of a target plant grown in mixed culture), of R. typhina was lower than that of C. coggygria. The lnRR of R. typhina and C. coggygria decreased and increased with increase in soil water content, respectively.ConclusionsRhus typhina has greater capacity to relatively stable growth to the drought condition than C. coggygria and has strong competition advantages in the mixture with C. coggygria, especially in the drought condition. Our study will help understand the causes of invasiveness and wide distribution of R. typhina under various moisture conditions and predict its expansion under climate change scenarios.

An ERA5-Based Hourly Global Pressure and Temperature (HGPT) Model

The Global Navigation Satellite System (GNSS) meteorology contribution to the comprehension of the Earth’s atmosphere’s global and regional variations is essential. In GNSS processing, the zenith wet delay is obtained using the difference between the zenith total delay and the zenith hydrostatic delay. The zenith wet delay can also be converted into precipitable water vapor by knowing the atmospheric weighted mean temperature profiles. Improving the accuracy of the zenith hydrostatic delay and the weighted mean temperature, normally obtained using modeled surface meteorological parameters at coarse scales, leads to a more accurate and precise zenith wet delay estimation, and consequently, to a better precipitable water vapor estimation. In this study, we developed an hourly global pressure and temperature (HGPT) model based on the full spatial and temporal resolution of the new ERA5 reanalysis produced by the European Centre for Medium-Range Weather Forecasts (ECMWF). The HGPT model provides information regarding the surface pressure, surface air temperature, zenith hydrostatic delay, and weighted mean temperature. It is based on the time-segmentation concept and uses the annual and semi-annual periodicities for surface pressure, and annual, semi-annual, and quarterly periodicities for surface air temperature. The amplitudes and initial phase variations are estimated as a periodic function. The weighted mean temperature is determined using a 20-year time series of monthly data to understand its seasonality and geographic variability. We also introduced a linear trend to account for a global climate change scenario. Data from the year 2018 acquired from 510 radiosonde stations downloaded from the National Oceanic and Atmospheric Administration (NOAA) Integrated Global Radiosonde Archive were used to assess the model coefficients. Results show that the GNSS meteorology, hydrological models, Interferometric Synthetic Aperture Radar (InSAR) meteorology, climate studies, and other topics can significantly benefit from an ERA5 full-resolution model.

Grazing and productivity alter individual grass size dynamics in semi‐arid woodlands

The spatial arrangement of perennial vegetation is critical for ecosystem function in drylands. While much is known about how vegetation patches respond to grazing and abiotic conditions, the size dynamics of individual plants is mostly limited to theoretical studies. We measured the size distribution (mean, variance, skewness) and density of individual grasses, and grass species composition at 451 sites spanning a range of grazing intensities across three broad vegetation communities in semi‐arid eastern Australia. We assessed the relative role of grazing by livestock (cattle and sheep), native (kangaroos) and introduced (rabbits) free ranging herbivores, and several environmental measures (productivity, diversity, composition and groundstorey plant cover) on the size distribution and density of individual grasses. We found mean grass size and density were more sensitive to shifts in grazing intensity and environmental conditions than size variance or the frequency of the smallest individuals (skewness), and shifts were mostly driven by site productivity and cattle and kangaroo grazing. Sheep grazing only reduced mean grass size, and rabbit grazing had no consistent effects. Importantly, we found that site productivity and species composition altered the impacts of grazing on grass density and size distribution. For example, increasing cattle grazing led to larger grasses in low productivity sites. It also led to larger, denser, more variable‐sized grasses among grass species from sites with finer soil texture. Increasing kangaroo grazing led to smaller, denser individuals among grass species from sites with coarse soil texture. At high diversity sites kangaroo grazing led to denser, more homogenised grass sizes with a lower frequency of small individuals. Understanding the in situ response of individual plant sizes gives us insights into the processes driving shifts in perennial vegetation patchiness, improving our ability to predict how the spatial arrangement of ecosystems might change under global change scenarios.

MaxEnt Modeling for Predicting the Current and Future Potential Geographical Distribution of Quercus libani Olivier

The purpose of the study was to model the current and potential future distribution of Quercus libani Olivier (Lebanon Oak), a tree species in Turkey, and to predict the changes in its geographical distribution under different climate change scenarios. In this study, 19 bioclimatic variables at a spatial resolution of 30 arc seconds (~1 km2) were used, collected from the WorldClim database. The bioclimatic data with high correlation according to 31 sets of presence data on the species were reduced with principal component analysis (PCA), and the current and potential distribution were identified using MaxEnt 3.4.1 software. In order to predict how the distribution of the species will be affected by climate change, its potential geographical distribution by 2050 and 2070 was modeled under the Representative Concentration Pathways (RCP) RCP 4.5 and RCP 8.5 scenarios of the species using the Community Climate System Model (CCSM, version 4), which is a climate change model based on the report of the fifth Intergovernmental Panel on Climate Change (IPCC). Change analysis was performed to determine the spatial differences between its current and future distribution areas. The study results showed that the suitable areas for the current distribution of Quercus libani Olivier cover 72,819 km2. Depending on the CCSM4 climate model, the suitable area will decline to 67,580 km2 by 2070, according to the RCP 4.5 scenario, or 63,390 km2 in the RCP 8.5 scenario. This may lead to a reduction in the future population of this species. The change analysis showed that suitable and highly suitable areas will decrease under global climate change scenarios (RCP 4.5 and RCP 8.5) for both current and future potential distribution areas. In this context, our study results indicate that for the management of this species, protective environmental measures should be taken, and climate change models need to be considered in land use and forest management planning.