Vertical Stratification of Insect Species Developing in Water-Filled Tree Holes

Forest ecosystems have a distinct vertical dimension, but the structuring of communities in this three-dimensional space is not well understood. Water-filled tree holes are natural microcosms structured in metacommunities. Here, we used these microcosms as model systems to analyze how insect communities and the occurrence and abundance of individual species are influenced by biotic and abiotic microhabitat characteristics, the vertical position of the tree hole, and stand-scale habitat availability. We found that both the characteristics of water-filled tree holes and their insect communities differ significantly between canopy and ground level. Individual insect species showed contrasting responses to the vertical position of the tree holes when important environmental factors at the stand and the tree-hole scale were considered. While some species, such as the mosquito Aedes geniculatus and the beetle Prionocyphon serricornis, decreased in abundance with increasing tree-hole height, the biting midge Dasyhelea sp., the non-biting midge Metriocnemus cavicola and the hoverfly Myiatropa florea increased in abundance. Our results suggest that vertical stratification in forests is most likely driven not only by variation in tree-hole microhabitat properties, i.e., niche separation, but also by individual species traits, such as adult dispersal propensity, food preferences and mating behavior of adult stages, and interspecific competition of larval stages. Therefore, communities of insect species developing in tree holes are likely structured by competition–colonization trade-offs predicted by metacommunity theory.

The Influence of Channel Planform and Slope Topography on Turbidity Current Overbank Processes: The Example of the Acquarone Fan (Southeastern Tyrrhenian Sea)

Overbank deposits provide a potentially valuable record of flows that have passed through a submarine channel. The architecture of overbank deposits has generally assumed to relate to autogenic processes related to channel construction. In previous models, which are largely based on passive margins, the distribution and geometry of these deposits is relatively simple, and hence generally predictable. Here, we show how the interaction of different flow types with the complex morphology on a highly-tectonically modified margin can profoundly affect overbank depositional processes, and hence also the resultant deposit geometry and architecture. Our case study is the Acquarone Fan, located in the intraslope Gioia Basin in the south-eastern Tyrrhenian Sea, whose topography is mainly controlled by the presence of the Acquarone structural ridge, which results in the confinement of the left south-west side of the channel-levee system. The research is carried out through analysis of multibeam bathymetric and high-resolution Chirp sub-bottom profiler data. Seven depositional units (Units I-VII) record the recent depositional history of the fan; their thickness has been mapped and their parent flow-types have been interpreted through their seismic response. According to unit thickness maps, two main patterns of deposition are recognized in the overbank area. Their depocenters coincide with different extensive sediment wave fields developed in specific tracts of the right levee and in the frontal splay area. We show that the location of the depocenters varies in time according to the prevalent flow-type and by its interaction with the surrounding seafloor topography and channel planform. We interpret that the lateral confinement of the channel by the structural high generates episodic rebound of the overspilling flow and the inversion of the channel asymmetry. The vertical stratification of the flow strongly influences the overbank deposition where the channel planform has a non-linear shape such as bends and knick-points. In particular, the vertical stratification influences the hydraulic jump size that conditions the amount of overspill and thus the location of overbank depocenters. This study highlights that variations in the sediment distribution and composition on the overbank can be related to the way different flows interact with tectonic setting.

Some Methodological Principles in Specialized FLT for the Professional Sphere

The article discusses the necessity to apply specific methodological principles in FLT for professional purposes due to the increasing interest of learners towards such training. The focus is on the essence of the concept of specialized economic language and on the method of Task-Based Approach. The necessary strategies for its application are also mentioned. The development of the skill for active linguistic performance is promoted mainly by the implementation of minimally structured training situations (authenticity). The constructivist principle of creating polymodular conditions, including the personal experience of the learner so as to stimulate the solution of the given problem are mentioned. For this purpose the specialized content and its peculiarities together with its exact location in the vertical stratification of specialized language are emphasized. The process of working with specialized text and one of the descriptors of CEFR are discussed. When working, the principles of subject-specific aspects are taken into consideration, placing the importance on the quality of teaching materials instead of their quantity, and prioritizing the sistematicity and the orientation of the content over the form.

Contesting the “Corrupt Elites,” Creating the “Pure People,” and Renegotiating the Hierarchies of the International Order? Populism and Foreign Policy-Making in Turkey and Hungary

This article explores the link between populism and hierarchies in international relations by examining the recent foreign policy-making in Turkey and Hungary—two countries run by populist leaders. We argue that when populists bring populism into foreign policy, they do so by contesting the “corrupt elites” of the international order and, simultaneously, attempt to create the “pure people” transnationally. The populists contest the “eliteness” and leadership status of these “elites” and the international order and its institutions, that is, the “establishment,” that these “elites” have come to represent by challenging them both in discourse and in action. The creation of the “pure people” happens by discursively demarcating the “underprivileged” of the international order as a subcategory based on religion and supplementing them with aid, thus mimicking the distributive strategies of populism, this time at the international level. We illustrate that when populist leaders, insert populism into foreign policies of their respective states, through contesting the “corrupt elites” and creating the “pure people,” the built-in vertical stratification mechanisms of populism that stems from the antagonistic binaries inherent to populism provide them with the necessary superiority and inferiority labels allowing them to renegotiate hierarchies in the international system in an attempt to modify the existing ones or to create new ones.

Nutrient ratios driven by vertical stratification regulate phytoplankton community structure in the oligotrophic western Pacific Ocean

The stratification of the upper oligotrophic ocean has a direct impact on biogeochemistry by regulating the components of the upper-ocean environment that are critical to biological productivity, such as light availability for photosynthesis and nutrient supply from the deep ocean. We investigated the spatial distribution pattern and diversity of phytoplankton communities in the western Pacific Ocean (WPO) in the autumn of 2016, 2017, and 2018. Our results showed the phytoplankton community structure mainly consisted of cyanobacteria, diatoms, and dinoflagellates, while the abundance of Chrysophyceae was negligible. Phytoplankton abundance was high from the equatorial region to 10∘ N and decreased with increasing latitude in spatial distribution. Phytoplankton also showed a strong variation in the vertical distribution. The potential influences of physicochemical parameters on phytoplankton abundance were analyzed by a structural equation model (SEM) to determine nutrient ratios driven by vertical stratification to regulate phytoplankton community structure in the typical oligotrophic ocean. Regions with strong vertical stratification were more favorable for cyanobacteria, whereas weak vertical stratification was more conducive to diatoms and dinoflagellates. Our study shows that stratification is a major determinant of phytoplankton community structure and highlights that physical processes in the ocean control phytoplankton community structure by driving the balance of chemical elements, providing a database to better predict models of changes in phytoplankton community structure under future ocean scenarios.

An Adaptive Non-Uniform Vertical Stratification Method for Troposphere Water Vapor Tomography

Global Navigation Satellite System (GNSS) water vapor tomography provides a four-dimensional (4-D) distribution of water vapor in the atmosphere for weather monitoring. It has developed into a widely used technique in numerical weather prediction (NWP). Vertical stratification is essential in discretizing the tomographic region. Traditional discretization methods divide the tomographic area into regular voxels with an equal height interval, which ignores the dynamic exponential distribution of water vapor. In recent years, non-uniform stratification methods have been widely validated by tomographic experiments. However, such experiments have not proposed a specific calculation method for stratification thickness. Therefore, in this paper, we introduced an adaptive non-uniform stratification method that follows the exponential distribution of water vapor in the tomographic region and presented the process of iterative calculation to acquire the optimal stratification interval. The proposed approach was applied based on the exponential decreasing trend in water vapor with increasing altitude. Moreover, it could adaptively calculate the interval of stratification height according to water vapor content. The tomographic experiments were performed using Global Positioning System (GPS) data from 19 ground-based stations in the Hong Kong Satellite Positioning Reference Station Network (SatRef) from 1 to 31 August 2019. The results indicated that, compared to the traditional stratification method, the root mean square error derived from the proposed approach was reduced by 0.26 g/m3. Additionally, severe weather can negatively affect the accuracy of the tomographic results. The results also showed that the accuracy of the tomographic results was reduced with increasing altitude. Moreover, the performance of the tomographic water vapor fields below 3000 m was improved by the proposed approach.

Vertical Distribution of Arthropod Assemblages and the Effects of Weather Conditions on Arthropod Rain in a Temperate Conifer Forest

Vertical stratification of forests results in the occurrence of different arthropod assemblages between the vertical layers. Fallen arthropods from the canopy layers (i.e., “arthropod rain”) are additional food sources for predators thriving on the forest floor (FF). However, the abundances of arthropods are strongly affected by weather conditions and vertical stratification. Therefore, in this study, we investigated the vertical distribution of arthropod assemblages and effects of temperature and precipitation on the arthropod rain in a temperate conifer (Cryptomeria japonica) forest. Arthropods were collected by water-pan traps and trunk-sticky traps in the upper canopy (UC; 16 m), lower canopy (10 m), and FF (0.5 m). Among the fallen arthropods collected by water-pan traps, wandering detritivores, and herbivores were more abundant ranging from the FF to the UC, whereas the abundance of wandering predators (mainly spiders) was similar in the upper and lower canopies. However, detritivores, herbivores, and predators showed the highest abundance in the UC among the flying arthropods. Wandering arthropods moved upward from the FF toward the tree trunks more frequently than downward, indicating the importance of arthropod immigration from the ground to arboreal habitats. Temperature and precipitation had different effects on fallen and moving arthropods among different taxonomic groups. Flying arthropods were affected only by temperature, while wandering detritivores and herbivores were affected by precipitation and temperature. Thus, the abundance of wandering and flying arthropods differed among the vertical layers of a temperate conifer forest; additionally, arthropod rain was closely associated with weather conditions.