environmental variability
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Geosciences ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 42
Author(s):  
Elena Romano ◽  
Luisa Bergamin ◽  
Mario Parise

Marine caves are characterized by wide environmental variability for the interaction between marine and continental processes. Their conditions may be defined as extreme for inhabiting organisms due to the enclosed morphology, lack of light, and scarcity of nutrients. Therefore, it is necessary to identify reliable ecological indicators for describing and assessing environmental conditions in these habitats even more than elsewhere. This review aims to provide the state of art related to the application of benthic foraminifera as proxies in the (paleo)ecological characterization of different habitats of marine caves. Special attention was addressed to a research project focused on Mediterranean marine caves with different characteristics, such as extent, morphology, freshwater influence, salinity, sediment type, oxygenation, and organic matter supply. This review aims to illustrate the reliability of foraminifera as an ecological and paleoecological indicator in these habitats. They respond to various environmental conditions with different assemblages corresponding to a very detailed habitat partitioning. Because marine caves may be considered natural laboratories for environmental variability, the results of these studies may be interpreted in the perspective of the global variability to understand the environmental drivers of future changes in marine systems.


2022 ◽  
pp. 096703352110618
Author(s):  
Orlando CH Tavares ◽  
Tiago R Tavares ◽  
Carlos R Pinheiro Junior ◽  
Luciélio M da Silva ◽  
Paulo GS Wadt ◽  
...  

The southwestern region of the Amazon has great environmental variability, presents a great complexity of pedoenvironments due to its rich variability of geological and geomorphological environments, as well as for being a transition region with other two Brazilian biomes. In this study, the use of pedometric tools (the Algorithms for Quantitative Pedology (AQP) R package and diffuse reflectance spectroscopy) was evaluated for the characterization of 15 soil profiles in southwestern Amazon. The AQP statistical package—which evaluates the soil in-depth based on slicing functions—indicated a wide range of variation in soil attributes, especially in the superficial horizons. In addition, the results obtained in the similarity analysis corroborated with the description of physical, chemical components and oxide contents in-depth, aiding the classification of soil profiles. The in-depth characterization of visible-near infrared spectra allowed inference of the pedogenetic processes of some profiles, setting precedents for future work aiming to establish analytical strategies for soil classification in southwestern Amazon based on spectral data.


2022 ◽  
Vol 5 (1) ◽  
Author(s):  
Peter van der Sleen ◽  
Pieter A. Zuidema ◽  
John Morrongiello ◽  
Jia Lin J. Ong ◽  
Ryan R. Rykaczewski ◽  
...  

AbstractMarine fish populations commonly exhibit low-frequency fluctuations in biomass that can cause catch volatility and thus endanger the food and economic security of dependent coastal societies. Such variability has been linked to fishing intensity, demographic processes and environmental variability, but our understanding of the underlying drivers remains poor for most fish stocks. Our study departs from previous findings showing that sea surface temperature (SST) is a significant driver of fish somatic growth variability and that life-history characteristics mediate population-level responses to environmental variability. We use autoregressive models to simulate how fish populations integrate SST variability over multiple years depending on fish life span and trophic position. We find that simulated SST-driven population dynamics can explain a significant portion of observed low-frequency variability in independent observations of fisheries landings around the globe. Predictive skill, however, decreases with increasing fishing pressure, likely due to demographic truncation. Using our modelling approach, we also show that increases in the mean and variance of SST could amplify biomass volatility and lessen its predictability in the future. Overall, biological integration of high-frequency SST variability represents a null hypothesis with which to explore the drivers of low-frequency population change across upper-trophic marine species.


Author(s):  
Mozzamil Mohammed ◽  
Bernd Blasius ◽  
Alexey Ryabov

AbstractThe dynamics of trait-based metacommunities have attracted much attention, but not much is known about how dispersal and spatial environmental variability mutually interact with each other to drive coexistence patterns and diversity. Here, we present a spatially explicit model of competition for two essential resources in a metacommunity on a one-dimensional environmental gradient. We find that both the strength of dispersal and the range of spatial environmental variability affect coexistence patterns, spatial structure, trait distribution, and local and regional diversity. Without dispersal, species are sorted according to their optimal growth conditions on the gradient. With the onset of dispersal, source-sink effects are initiated, which increases the effects of environmental filtering and interspecific competition and generates trait lumping, so that only a few species from an environment-defined trait range can survive. Interestingly, for very large dispersal rates, species distributions become spatially homogeneous, but nevertheless two species at the extreme ends of the trade-off curve can coexist for large environmental variability. Local species richness follows a classic hump-shaped dependence on dispersal rate, while local and regional diversity exhibit a pronounced peak for intermediate values of the environmental variability. Our findings provide important insights into the factors that shape the structure of trait-based metacommunities.


Author(s):  
Robin P. M. Gauff ◽  
Christophe Lejeusne ◽  
Laure Arsenieff ◽  
Olivier Bohner ◽  
Jérôme Coudret ◽  
...  

2022 ◽  
Vol 34 ◽  
Author(s):  
Matheus Vieira da Silva ◽  
Jascieli Carla Bortolini ◽  
Susicley Jati

Abstract Aim We aimed to characterize the structure of the phytoplankton community and identify the main environmental factors driving the community in five reservoirs constructed in the region of the high Paraná River. Methods The phytoplankton and environmental variables were collected at the lacustrine region of the reservoir, between November 2013 and November 2014, with interval between collections ranged from 3 to 6 months. The richness and biomass of the phytoplankton community were measured as a response to the spatial and temporal environmental variability. Data from environmental variables was analyzed by Principal Component Analysis (PCA). Non-Metric Multidimensional Scaling Analyzes (NMDS) were performed on the richness and biomass data of the phytoplankton community. Results We identified 80 taxa distributed in 11 taxonomic classes, from which Cyanobacteria and Chlorophyceae were best represented. We did not observe significant temporal variation for either environmental variables or attributes of the phytoplankton community, which may be related to the prolonged drought in this period in the Brazilian Southwest. Higher phytoplankton richness and biomass were found in the Três Irmãos (Tiete River), reservoir located in the most anthropized basin in the country. Cyanobacteria and dinoflagellates dominated the biomass in all reservoirs during the studied period. The Ilha Solteira, Jupiá and Porto Primavera reservoirs showed a tendency to decrease in the values of phytoplankton richness and biomass, and the reservoirs built in series in the Paraná River probably have strong interdependence, according to the CRCC concept. Conclusions Spatial variation in phytoplankton attributes was influenced mainly by the position occupied by the reservoir in the hydrographic basin, water retention time (RT) and nutrient concentrations in each reservoir.


2022 ◽  
Vol 9 (1) ◽  
Author(s):  
C. D. Perl ◽  
Z. B. Johansen ◽  
V. W. Jie ◽  
Z. Moradinour ◽  
M. Guiraud ◽  
...  

Differences in organ scaling among individuals may play an important role in determining behavioural variation. In social insects, there are well-documented intraspecific differences in colony behaviour, but the extent that organ scaling differs within and between colonies remains unclear. Using 12 different colonies of the bumblebee Bombus terrestris , we aim to address this knowledge gap by measuring the scaling relationships between three different organs (compound eyes, wings and antennae) and body size in workers . Though colonies were exposed to different rearing temperatures, this environmental variability did not explain the differences of the scaling relationships. Two colonies had differences in wing versus antenna slopes, three colonies showed differences in wing versus eye slopes and a single colony has differences between eye versus antenna slopes. There are also differences in antennae scaling slopes between three different colonies, and we present evidence for putative trade-offs in morphological investment. We discuss the utility of having variable scaling among colonies and the implication for understanding variability in colony fitness and behaviour.


2021 ◽  
Vol 9 (3) ◽  
pp. 161-170
Author(s):  
Kutoya Kusse ◽  
Gedion Ermias ◽  
Dawit Darch

Enset (Ensete ventricosum (Welw.) Cheesman) is economically a useful crop that provides forage for animals, construction materials, fuel and traditionally it is used as a medicine. The production and productivity of enset is mainly affected by many diseases and pests which causes serious devastating cultivar diversity and finally a yield lose of the crop. Moreover, its production sustainability is also threatened by many factors like wild animal pests, enset root pests, high population pressure and the shift of the producers to cash-oriented crop production. The assessment on enset production, its challenges and controlling methods was carried out in Debub Ari district of South Omo Zone, in southern Ethiopia from November 2021 to January 2021 in four randomly selected representative Kebeles. Simple random sampling method were employed to select a representative sample of the study (n = 138). Qualitative and quantitative data were collected through structured questionnaire, focus group discussions, individual interview and personal observations. The collected data were analyzed by using appropriate simple descriptive statistics. The land under enset production is declining from time to time, as well as its production also declines due to social, bio-physical and environmental factors such as land fragmentation, enset bacterial welt, insects and pests and environmental variability factors. To overcome these factors farmers practicing many controlling methods such as by burying the infected plants, restricting the movement of infected plant materials, sterilizing production tools and raising awareness about how to protect disease like enset bacterial welt and use of aluminum phosphate for pests like mole rate.


Poljoprivreda ◽  
2021 ◽  
Vol 27 (2) ◽  
pp. 50-55
Author(s):  
Domagoj Stepinac ◽  
Hrvoje Šarčević ◽  
Ivica Buhiniček ◽  
Mirko Jukić ◽  
Bojan Marković ◽  
...  

Thousand kernel weight (TKW) is an important yield component trait affected by the environmental conditions. This study’s objectives were to determine an environmental variability for the TKW in 32 maize hybrids, sorted in four FAO maturity groups (FAO300, 400, 500 and 600), and to compare 12 environments in Croatia (six locations in two years) according to the joint linear regression and stability analyses across the maturity groups. In general, the effects of the environment, genotype, and their interaction (GEI) were significant. A three-factor ANOVA revealed the greatest and highly significant year effect, while the location effect was non-significant across all four FAO groups. A stability analysis did not detect any preferences with regard to the locations and trends across the FAO groups. It indicates that all locations in the Pannonian region included in this study were suitable for an evaluation of the TKW in maize genotypes belonging to all maturity groups. The TKW seems to be an appropriate yield-component trait for maize breeding due to a high heritability and linear GEI nature.


2021 ◽  
Author(s):  
Laura K. Blamey ◽  
Éva E. Plagányi ◽  
Trevor Hutton ◽  
Roy A. Deng ◽  
Judy Upston ◽  
...  

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