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Climate change is impacting marine species, leading to shifts in their distribution to higher latitudes and to deeper locations. Parasite communities are dynamic systems influenced by biotic and abiotic factors, making them valuable tools for studying ecological processes of their hosts. This work aims to assess possible changes in parasite structure that occurred in the northern stock of Cynoscion guatucupa in the Argentine Sea, over approximately 25 years, by using parasites as tags in a region characterized as a hotspot of significant warming in recent decades. Parasite assemblages of adult and juvenile fish from two periods caught at two regions of the Argentine Sea were analyzed. Species richness remained relatively constant across samples, although four of the eight compared species from juvenile fish showed significant increases in prevalence, while for adults three species decreased. Differences in parasite assemblages were significant between periods, but not between regions, indicating that the stock structure has apparently remained stable in recent years, even under a warming process that, in turn, seems to have affected its parasite assemblages which however, continue showing homogeneous parasitological attributes throughout the habitats. Most results indicate that changes in parasite burdens are not related to the population density or geographic distribution of C. guatucupa, but to changes in temperature, salinity or in the density of top predators. Parasites seem to have felt the impact of global change before their host, thus, they can be considered early sentinels to monitor the stability and distribution of this important resource. [ABSTRACT FROM AUTHOR]

The Pacific oyster Crassostrea gigas, one of the most exploited molluscs in the world, has suffered from massive mortality in recent decades, and the occurrence mechanisms have not been well-characterized. In this study, to reveal the relationship of associated microbiota to the fitness of oysters, temporal dynamics of microbiota in the gill, hemolymph, and hepatopancreas of C. gigas during April 2018–January 2019 were investigated by 16S rRNA gene sequencing. The microbiota in C. gigas exhibited tissue heterogeneity, of which Spirochaetaceae was dominant in the gill and hemolymph while Mycoplasmataceae enriched in the hepatopancreas. Co-occurrence network demonstrated that the gill microbiota exhibited higher inter-taxon connectivity while the hemolymph microbiota had more modules. The richness (Chao1 index) and diversity (Shannon index) of microbial community in each tissue showed no significant seasonal variations, except for the hepatopancreas having a higher richness in the autumn. Similarly, beta diversity analysis indicated a relatively stable microbiota in each tissue during the sampling period, showing relative abundance of the dominant taxa exhibiting temporal dynamics. Results indicate that the microbial community in C. gigas showed a tissue-specific stability with temporal dynamics in the composition, which might be essential for the tissue functioning and environmental adaption in oysters. This work provides a baseline microbiota in C. gigas and is helpful for the understanding of host-microbiota interaction in oysters. [ABSTRACT FROM AUTHOR]

Soil moisture (SM) is a key factor that determines the stability and functioning of desert ecological systems, but has been rarely studied due to the difficulty of sampling. The characterization of the temporal stability of soil moisture (SM TS) and its statistical parameters is much needed. To identify suitable locations to estimate SM status for the study area, and obtain greater insights into the SM TS of the Horqin Sand Land, SM was measured in a fixed dune (FD) over a depth profile of 0–1 m and on 14 occasions between May and July 2021. These data were combined with soil property and precipitation measurements to assess the SM TS and determine the optimal locations that could represent the mean SM of the area. Results indicated that (1) the mean SM of FD varied from 1.98% to 6.73%, with minimal spatial variation (mean standard deviation (STD) < 3%; mean coefficient of variation (CV) ranging between 42% and 56%). (2) SM continually decreased over time until considerable precipitation occurred. Temporal dynamics decreased with increasing soil depth. Further, only larger precipitation events (> 20 mm) led to significant SM increases. In deeper soil layers (> 60 cm), the SM response exhibited a lag. (3) The relationship between STD and mean SM indicated that SM becomes more variable under wetter conditions, such that SM increases were associated with CV increases in this region. (4) The Spearman's rank correlation coefficient (RS) values between different sampling dates indicated that most of the relationships were significant (p < 0.05), especially for soils in the 60–100 cm layer. (5) The mean values of mean relative differences (MRD) were smaller for soils < 40 cm and the mean corresponding standard deviation of MRD (SDRD) values were smaller for soils < 60 cm, indicating that SM tended to be more stable in deeper soil layers. (6) Linear regression analyses between the estimated means obtained from the identified locations and the actual field means led to the identification of the best representative SM locations for the 0–20, 20–40, 40–60, 60–80, and 80–100 cm layers at locations 8, 16, 8, 11, and 6, respectively. (7) The accumulated temporal stability index (ITS) of SM for different soil layers suggested that the 12th location (with a minimum ITS value) was the most representative location to approximate the mean SM of different soil layers in the FD. However, linear regression analyses of the SM between the actual field mean and that of the 12th representative location revealed a satisfactory fit only for soil layers above 40 cm. This study contributes to our understanding of SM patterns in arid environments, which have important implications for ground sampling design and hydro-logic modeling. [ABSTRACT FROM AUTHOR]

The semi-Lagrangian Reproducing Kernel (SL RK) has been successfully applied to simulations of extreme deformation problems thanks to intensive advancements in meshfree methods in recent decades. The SL RK shape function is constructed centered at a material point with a fixed spatial radius, and therefore it is a time-dependent function. When the SL RK is introduced in the weak form of the equation of motion, the time derivatives of SL RK lead to convective terms in the semi-discrete equation, significantly reducing the computational efficiency and accuracy. This paper presents a novel approximation scheme in which displacement, velocity, and acceleration are approximated by the same SL RK at a time instant. Consequently, the proposed concurrent SL RK formulation avoids the need to compute the convective terms, offering an effective numerical solution for high-strain rate dynamic problems. Furthermore, an eigenvalue analysis is performed on the semi-discrete equation of motion to investigate the temporal stability of the concurrent SL RK formulation. A comprehensive study of the eigenvalue and critical time step is conducted to identify the effective parameters for the stability of the system. Several manufactured dynamic problems are studied to validate the analytical estimate. The estimated analytical eigenvalue and the critical time step are consistent with the numerical result. [ABSTRACT FROM AUTHOR]

Recent extremes of flood and drought across Australia have raised questions about the recurrence of such rare events and highlighted the importance of understanding multi-decadal climate variability. However, instrumental records over the past century are too short to adequately characterise climate variability on multi-decadal and longer timescales or robustly determine extreme event frequencies and their duration. Palaeoclimate reconstructions can provide much-needed information to help address this problem. Here, we use the 600-year hydroclimate record captured in the eastern Australian and New Zealand Drought Atlas (ANZDA) to analyse drought and pluvial frequency trends for East Australian Natural Resource Management (NRM) clusters. This partitioning of the drought atlas grid points into recognised biophysical areas (i.e. NRM clusters) revealed their differences and similarities in drought intensity and pluvial events over time. We find sustained multi-decadal periods of a wet–dry geographic 'seesaw' between eastern to central and southern NRMs (e.g. 1550–1600 CE and 1700–1750 CE). In contrast, other periods reveal spatially consistent wetting (e.g. 1500–1550 CE) or drying (e.g. 1750–1800 CE). Emerging hot spot analysis further shows that some areas that appear naturally buffered from severe drought during the instrumental period have a greater exposure risk when the longer 600-year record is considered. These findings are particularly relevant to management plans when dealing with the impacts of climate extremes developed at regional scales. Our results demonstrate that integrating and extending instrumental records with palaeoclimate datasets will become increasingly important for developing robust and locally specific extreme event frequency information for managing water resources. [ABSTRACT FROM AUTHOR]

Entrepreneurial identity represents a powerful motivating force that can help explain individuals' entrepreneurial activity and has been found to be relevant to several new business venturing decisions. Although identity may entail some degree of temporal stability, personal agency and social interactions may change it. While understanding entrepreneurial identity formation and development is a promising research topic, longitudinal analyses are lacking. In this study, we propose a longitudinal model in which intra-individual entrepreneurial identity aspirations exhibit path dependency, and test different types of entrepreneurial experiences as mediators affecting this relationship. Applying structural equation modeling to a longitudinal sample composed of individuals formerly enrolled in higher education programs, we found that past entrepreneurial identity aspirations predicted identity aspirations 11 years later. We also found that, while prior successful entrepreneurial experiences positively influenced current identity aspirations, unsuccessful experiences did not decrease them. It is noteworthy that these results hold even when considering working for others in new business projects as an (indirect) entrepreneurial experience. Our study contributes to the literature by extending the scarce longitudinal evidence that supports the temporal stability of entrepreneurial identity and by adding novel evidence regarding the mediating impact of real-life entrepreneurial experiences while considering both their direct and indirect nature and their positive and negative outcomes. This study may be relevant to policymakers and entrepreneurship educators by providing evidence of a virtuous cycle between entrepreneurial identity and action and its boundary conditions. [ABSTRACT FROM AUTHOR]

The role of silver–silver chloride electrode for providing the reference potential is quite important for the precise potentiometric measurements. Our study focuses to find the conditions for its optimal use, especially, in perspective for a long-term viability of electrode. In particular, we reassessed the temporal stability of the standard potential and presented the results of its measurement for a time span of ten years. [ABSTRACT FROM AUTHOR]

The mechanism supporting the stability of complex food webs is an important, yet still controversial issue in ecology. Integrating the bioenergetic model with a natural plankton food web with empirical organism body mass distribution, we studied the effects of taxa diversity, nutrient enrichment simulation and connectance on the stability of plankton, and the underlying mechanisms. The behavior and functions of plankton with different body masses in the system were also explored. The results showed that genus richness promoted the temporal stability of community but reduced that of population. Meanwhile, the effects of taxon extinction on community biomass and temporal stability depended on the body masses of those lost taxa. Enrichment decreased phytoplankton and zooplankton community stability directly by increasing the temporal variability of biomass and indirectly by reducing taxa diversity. Enrichment preferentially caused phytoplankton taxa with the highest individual biomass to go extinct and the ones with smaller to increase in biomass. The effects, as well as the underlying mechanisms of connectance on phytoplankton and zooplankton stability were different. High connectance promoted the persistence and biomasses of both zooplankton and small-bodied phytoplankton but reduced those of larger-bodied phytoplankton. The results and methodology in this research will be helpful in understanding and analyzing the stability of plankton communities. [ABSTRACT FROM AUTHOR]

Background: Holothuria (Halodeima) atra Jaeger, 1833 is a tropical sea cucumber usually harvested for the "bêche-de-mer" trade market. It has been reported to reproduce both sexually, through gamete spawning, or asexually, through fission. To date, no study has ever investigated clonality, nor genetic connectivity, among its populations, using microsatellite markers. Methods and results: We isolated the first 21 microsatellite loci specific for H. atra, which were then used to investigate clonal diversity, genetic structure and diversity among 44 H. atra individuals sampled in Reunion Island (southwestern Indian Ocean), over two seasons. All 21 loci were polymorphic, with number of alleles per locus ranging from 2 to 10. No repetitive multi-locus genotype (MLG) and few clonal lineages (MLL) were found. Observed heterozygosities per locus and season ranged from 0.000 to 0.909, while expected heterozygosities ranged from 0.290 to 0.882. Four loci were at Hardy–Weinberg equilibrium for both seasons, all others presenting a deficit of heterozygotes in one or both seasons. Meanwhile, no genetic differentiation was detected between seasons, according to assignment tests and global FST. Conclusions: These results suggest low asexual propagation in this population. These loci represent useful tools to better understand reproductive strategies and population connectivity of H. atra, and thus provide relevant knowledge for efficient management. [ABSTRACT FROM AUTHOR]

Understanding the temporal behaviour of soil moisture in different environments is essential considering its importance in hydrological processes. Few studies have addressed its dynamics in a subtropical climate, in view of temperature variations throughout the year and well-distributed precipitation events which are characteristics that affect the behaviour of soil moisture over time. The temporal stability of soil moisture was investigated in two sets of data collected from a small watershed in southern Brazil. We used multiple linear regression (MLR) to evaluate whether points with greater temporal stability contributed as predictor variables of the models for estimating soil moisture. Soil moisture was monitored in the superficial (0–10 cm) and subsurface (10–20 cm) layers at 39 points with variations in soil characteristics and topography. To assess the temporal stability of soil moisture, two statistical techniques and MLR models were used to identify the topographic, climatological and soil property variables, as well as those that influenced the dynamics of the soil water content. The results showed that the factors of slope, terrain elevation, microporosity and evapotranspiration were determinants for the strong performance of the models, and that the inclusion of points with greater temporal stability helped to improve the estimate in certain datasets. Therefore, the results of this study indicate that the set of results that express topographic factors, land use and cover, along with the soil physical properties should be considered to characterise the temporal stability of soil moisture. [ABSTRACT FROM AUTHOR]

Background and aims: Nitrogen (N) addition affects plant biodiversity and community structure, subsequently altering the stability of above-ground net primary productivity (ANPP) in grassland ecosystems. However, the effect of adding different nitrogen compounds and their subsequent interactions with mowing on the stability of both below-ground net primary productivity (BNPP) and total net primary productivity (TNPP) are largely unknown.This study compared the impact of adding two nitrogen compounds, NH4NO3 and urea, on the temporal stability of ANPP, BNPP, and TNPP in mowed and unmowed saline-alkaline grasslands.We found that the ANPP temporal stability in unmowed grasslands was not affected by NH4NO3 addition but increased with urea addition. Conversely, the ANPP temporal stability in mowed grasslands decreased with NH4NO3 addition and was not affected by urea addition. Mowing decoupled the ANPP and BNPP temporal stability responses to nitrogen addition. Without mowing, the BNPP temporal stability in response to adding different forms of nitrogen aligned with that of ANPP; however, with mowing, the BNPP temporal stability was not affected by adding NH4NO3 or urea, exhibiting an inconsistent trend of change in comparison to the ANPP temporal stability. The ANPP resistance indirectly regulates the response of the BNPP temporal stability to nitrogen addition in unmowed grasslands, whereas the BNPP temporal stability was not affected by plant above-ground indicators in mowed grasslands.Overall, our study addresses the scarcity of research on ecosystem temporal stability in saline-alkaline grasslands and demonstrates that mowing management can regulate the effects of different forms of nitrogen addition on ecosystem stability.Methods: Nitrogen (N) addition affects plant biodiversity and community structure, subsequently altering the stability of above-ground net primary productivity (ANPP) in grassland ecosystems. However, the effect of adding different nitrogen compounds and their subsequent interactions with mowing on the stability of both below-ground net primary productivity (BNPP) and total net primary productivity (TNPP) are largely unknown.This study compared the impact of adding two nitrogen compounds, NH4NO3 and urea, on the temporal stability of ANPP, BNPP, and TNPP in mowed and unmowed saline-alkaline grasslands.We found that the ANPP temporal stability in unmowed grasslands was not affected by NH4NO3 addition but increased with urea addition. Conversely, the ANPP temporal stability in mowed grasslands decreased with NH4NO3 addition and was not affected by urea addition. Mowing decoupled the ANPP and BNPP temporal stability responses to nitrogen addition. Without mowing, the BNPP temporal stability in response to adding different forms of nitrogen aligned with that of ANPP; however, with mowing, the BNPP temporal stability was not affected by adding NH4NO3 or urea, exhibiting an inconsistent trend of change in comparison to the ANPP temporal stability. The ANPP resistance indirectly regulates the response of the BNPP temporal stability to nitrogen addition in unmowed grasslands, whereas the BNPP temporal stability was not affected by plant above-ground indicators in mowed grasslands.Overall, our study addresses the scarcity of research on ecosystem temporal stability in saline-alkaline grasslands and demonstrates that mowing management can regulate the effects of different forms of nitrogen addition on ecosystem stability.Results: Nitrogen (N) addition affects plant biodiversity and community structure, subsequently altering the stability of above-ground net primary productivity (ANPP) in grassland ecosystems. However, the effect of adding different nitrogen compounds and their subsequent interactions with mowing on the stability of both below-ground net primary productivity (BNPP) and total net primary productivity (TNPP) are largely unknown.This study compared the impact of adding two nitrogen compounds, NH4NO3 and urea, on the temporal stability of ANPP, BNPP, and TNPP in mowed and unmowed saline-alkaline grasslands.We found that the ANPP temporal stability in unmowed grasslands was not affected by NH4NO3 addition but increased with urea addition. Conversely, the ANPP temporal stability in mowed grasslands decreased with NH4NO3 addition and was not affected by urea addition. Mowing decoupled the ANPP and BNPP temporal stability responses to nitrogen addition. Without mowing, the BNPP temporal stability in response to adding different forms of nitrogen aligned with that of ANPP; however, with mowing, the BNPP temporal stability was not affected by adding NH4NO3 or urea, exhibiting an inconsistent trend of change in comparison to the ANPP temporal stability. The ANPP resistance indirectly regulates the response of the BNPP temporal stability to nitrogen addition in unmowed grasslands, whereas the BNPP temporal stability was not affected by plant above-ground indicators in mowed grasslands.Overall, our study addresses the scarcity of research on ecosystem temporal stability in saline-alkaline grasslands and demonstrates that mowing management can regulate the effects of different forms of nitrogen addition on ecosystem stability.Conclusions: Nitrogen (N) addition affects plant biodiversity and community structure, subsequently altering the stability of above-ground net primary productivity (ANPP) in grassland ecosystems. However, the effect of adding different nitrogen compounds and their subsequent interactions with mowing on the stability of both below-ground net primary productivity (BNPP) and total net primary productivity (TNPP) are largely unknown.This study compared the impact of adding two nitrogen compounds, NH4NO3 and urea, on the temporal stability of ANPP, BNPP, and TNPP in mowed and unmowed saline-alkaline grasslands.We found that the ANPP temporal stability in unmowed grasslands was not affected by NH4NO3 addition but increased with urea addition. Conversely, the ANPP temporal stability in mowed grasslands decreased with NH4NO3 addition and was not affected by urea addition. Mowing decoupled the ANPP and BNPP temporal stability responses to nitrogen addition. Without mowing, the BNPP temporal stability in response to adding different forms of nitrogen aligned with that of ANPP; however, with mowing, the BNPP temporal stability was not affected by adding NH4NO3 or urea, exhibiting an inconsistent trend of change in comparison to the ANPP temporal stability. The ANPP resistance indirectly regulates the response of the BNPP temporal stability to nitrogen addition in unmowed grasslands, whereas the BNPP temporal stability was not affected by plant above-ground indicators in mowed grasslands.Overall, our study addresses the scarcity of research on ecosystem temporal stability in saline-alkaline grasslands and demonstrates that mowing management can regulate the effects of different forms of nitrogen addition on ecosystem stability. [ABSTRACT FROM AUTHOR]

A thick film flow on a non-isothermal vertical cylinder due to gravity is analyzed for temporal and spatiotemporal stability. The model equation is derived by neglecting inertial terms and keeping the full curvature term in the normal stress balance. The thermoviscous and thermocapillary effects are also considered. The film aspect ratio with respect to cylinder radius leads to an increase followed by a decrease in the temporal growth rate. For a cooled substrate, the film can be stabilized for a moderate aspect ratio. Spatiotemporal stability analysis is performed using the Briggs criterion. The aspect ratio significantly affects the spatiotemporal stability of the film. Absolutely unstable regimes are found for small and much larger values of the Bond number, with a convectively unstable regime for moderate values. The critical condition is found that leads to a relation between different model parameters such as Marangoni number, thermoviscosity number, and aspect ratio for which the film is absolutely unstable films for all values of Bond numbers. An opposing pressure gradient is also included in the model through normal stress balance, which can arise due to a counter-current gas flow. While this pressure gradient does not affect the temporal growth rates but promotes absolute instability. Non-linear computations are done to validate the growth rates from both linear temporal and spatiotemporal stability analyses. It is observed that the gaussian disturbance leads to traveling waves well beyond the saturation. The droplet size and gap between two subsequent droplets increase with the gas pressure gradient, thermoviscosity number, and Marangoni number. [ABSTRACT FROM AUTHOR]

Estimates of non-market values are valuable for policy makers. However, evidence of the stability of value estimates over long timeframes is limited. That can reduce the usefulness of such values in benefit transfer over time. Furthermore, the values might be affected by the choice of presentation of alternatives (e.g., labeled versus unlabeled). Most of the literature comparing the willingness-to-pay (WTP) estimates lacks an investigation of temporal stability for labeled and unlabeled alternatives. In this case study, the temporal stability of WTP estimates for emissions reduction has been assessed for labeled and unlabeled alternatives. Emissions reduction, certainty of emissions reduction and the options for emissions reductions such as green power, efficient technologies and carbon capture were used to identify respondents' WTP. The results show that WTP has changed significantly over the course of 10 years. The case study identified that WTP was larger for labeled alternatives than for unlabeled alternatives. The results indicate that WTP estimated from unlabeled alternatives may be more sensitive to temporal effects than labeled alternatives. [ABSTRACT FROM AUTHOR]

Background and aims: Plant community stability is threatened by anthropogenic climate changes such as increased precipitation. Arbuscular mycorrhizal (AM) fungi have been shown to drive the resistance of ecosystems against climate changes to provide stable ecosystem functions. However, how AMF affects plant community stability under climate change is still not sufficiently clear in Central Asia. Methods: A comprehensive study was conducted with increased precipitation and suppression of AMF in mycorrhizal and non-mycorrhizal plant communities, respectively. Changes in plant community composition and aboveground biomass were measured, and the temporal stability of plant community was calculated. Results: Mycorrhizal plant community responded more sensitively to the increased precipitation and suppression of AMF than non-mycorrhizal plant community. Species synchrony and population variability were only significantly changed by increased precipitation in the mycorrhizal plant community. The stability of dominant and mycorrhizal plants were positively related to community temporal stability of both plant communities. While contrasted with the positive effects of increased precipitation on community temporal stability, increased precipitation reduced community temporal stability by increasing temporal variations of plant biomass in the mycorrhizal plant community, and by decreasing plant diversity in the non-mycorrhizal plant community. However, AMF buffer the decreases in community stability by increasing plant community biomass under increasing precipitation. Conclusion: Our findings highlight ongoing increases in precipitation potentially weaken the temporal stability of ephemeral plant communities in the desert ecosystem stability; however, AMF can alleviate these negative effects through increasing community biomass, especially in the plant community dominated by mycorrhizal species. [ABSTRACT FROM AUTHOR]

Background: Late talking (LT) in toddlers is a risk factor for language weakness that may interfere with the development of using language to regulate behavior and emotion and contribute to the development of behavior problems from early childhood. This study examined the temporal stability of parent-reported behavior problems among Mandarin-speaking LT toddlers from ages 2 to 4 in Taiwan. Methods: Thirty-one LT and 31 typical language development (TLD) toddlers were assessed for their vocabulary production at age 2 with the Words and Sentences Forms of the MacArthur-Bates Communicative Developmental Inventories Toddler Form (Taiwan version). Additionally, participants' receptive and expressive language abilities were assessed using the receptive and expressive language subscales of the Bayley Scales of Infant and Toddler Development, Third Edition. At age 4, the Child Language Disorder Scale-Revised was applied and included the two core subtests for auditory comprehension and expressive communication. At ages 2 and 4 years, behavior problems were assessed with the Child Behavior Checklist. Results: There was a higher percentage of participants with persistent behavior problems among LT toddlers than among TLD toddlers. Moreover, toddlers with larger vocabularies were less likely to develop withdrawal behaviors by preschool age. Conclusions: This study supported the temporal stability of parent-reported behavior problems among LT toddlers across early childhood. Early identification of and intervention for behavior problems associated with LT in toddlerhood is essential to alleviate their behavior problems later in preschool years. [ABSTRACT FROM AUTHOR]

Better characterizing the spatio-temporal pattern of water quality would increase the ability to effectively manage water resources. This study applied the concept of temporal stability analysis (TSA) to explore the temporal characteristics of spatial variability in surface water quality. Measurement data from 41 monitoring stations in Qiantang River, China during 2017–2019 were used for analysis. The data included four water quality indicators: dissolved oxygen (DO), permanganate index (CODMn), total phosphorus (TP), and ammonia nitrogen (NH3–N). A Spearman's rank correlation for each pair of monitoring times was performed to characterize the spatial pattern of water quality. A temporal analysis of relative differences was applied to examine the temporal stability of the sampling sites. The rank correlation analysis suggests that the spatial pattern of water quality was maintained for a specific period of time and the TP concentration was most temporally stable compared with the other three indicators across the study area. The standard deviation of the relative difference (SDRD) and index of temporal stability (ITS) were found to be better for identifying the stable sites compared to the mean absolute bias error (MABE) and root mean square error (RMSE) in this study. A correlation analysis between the temporal stability indices and potential influencing factors showed that land use proportions (forest, built-up land, and agricultural land), and socio-economic indicators (gross domestic product [GDP] and population density) were closely associated with the temporal stability of water quality. The results showed evidence that the TSA method was feasible and effective in identifying the temporal stability of surface water quality and optimizing the water quality monitoring program. This study's method and findings can help improve surface water quality monitoring strategies and water resource management. [ABSTRACT FROM AUTHOR]

Small to medium irrigation ponds provide substantial quantities of water for irrigation in the Mid-Atlantic region of the U.S. The concentrations of the fecal indicator organism Escherichia coli (E. coli) are used to evaluate the microbial water quality of irrigation sources. Little is known about the spatiotemporal variability of E. coli concentrations in pond water and the possible effects on monitoring and management of the microbial quality of irrigation water from these ponds. The objective of this work was to test the hypotheses that (a) spatial patterns of E. coli concentrations exist that are preserved both intra- and interannually, and (b) persistent spatial patterns in water quality parameters exist and correlate with persistent patterns of E. coli concentrations. Sampling was conducted fortnightly during the summer months in 2016 to 2018 and consisted of taking water quality measurements at 23 and 34 locations in ponds P1 and P2, respectively. Interannual variability of E. coli was observed in both ponds as was substantial spatial variability of E. coli concentrations within each year. The mean relative difference (MRD) analysis was used to identify temporally stable patterns of E. coli concentrations within the ponds. These patterns found for individual years showed significant positive correlations with each other and with the overall pattern derived from the 3-year dataset. Correlation coefficients of patterns varied from 0.487 to 0.842 in P1 and from 0.467 to 0.789 in P2 (p < 0.05). MRD patterns of water quality parameters and of E. coli concentrations were also significantly correlated. Within the 3-year dataset, the highest positive correlations were observed for chlorophyll-a and turbidity while the dissolved oxygen concentrations demonstrated the greatest negative correlations. Results of the present study emphasize the advisability and feasibility of finding temporally stable spatial patterns in microbial water quality within irrigation ponds. [ABSTRACT FROM AUTHOR]

Soil water content (SWC) plays a crucial role in simulating hydrological process, guiding reforestation and controlling soil erosion in mountainous regions. Spatial-temporal variability of SWC increases the difficulty of quantifying SWC pattern in the prediction of soil moisture. Temporal stability analysis of SWC can reduce the labor consuming and simplify the costly field monitoring. This study aimed to evaluate the temporal stability of SWC at hourly, daily and monthly temporal periods and its controlling factors at a hillslope in the Three Gorges region. The SWC of five soil depths was monitored at 5 topographic locations (toe, lower, middle, upper and top slope positions) along a 170 m hillslope in the Three Gorges region (110°04′ ∼112°04′ E, 29°53′∼31°34′ N), Yichang City, Hubei Province, China from May 4th, 2018 to May 3rd, 2019. The results showed that the coefficient of variation of SWC ranged from 4% to 49%, which increased with rising soil depth within 40 cm but thereafter decreased. However, the high Spearman's rank coefficients (P<0.05) indicated strong temporal stability at three temporal periods. The representative locations (RLs) varied in the different soil depths, which were toe, upper and middle slope positions at 0∼40, 40∼60 and 60∼80 cm depths of the investigated hillslope, respectively. Saturated hydraulic conductivity served as a dominant factor controlling the temporal stability of SWC. The result advances our thorough understanding of hydrology and soil water resource in the Three Gorges region. [ABSTRACT FROM AUTHOR]

Animal shelters face diverse challenges, which often necessitate making life-or-death decisions for animals in their care. One strategy used to determine whether admitting, adoption, or euthanasia is appropriate is to assess an animal’s in-shelter or pre-admission behavior to infer its “personality.” Shelters do this because potential adopters are often interested in knowing an animal’s personality as it provides information about whether the animal will fit in their home. However, shelter behavior assessments are a broad topic. To narrow focus, I explore a relatively novel development: feline behavior assessments. These assessments suggest that shelter workers can make a valid inference from in-shelter behavior to long-term, consistent personality. I argue that assessments do not, and might not be able to, validly infer personality in shelters; I utilize recent philosophical work by Kaiser & Müller (Biol Philos 36:1–25, 2021) on personality to do so. I build on their work by showing how shelter assessments do not meet their criteria and fall victim to epistemic bias in privileging some behaviors. Because feline assessments fail to meet philosophically robust definitions of animal personality and have methodological biases, these assessments do not provide valid insight into a shelter animal’s personality and should not be used. [ABSTRACT FROM AUTHOR]

Objective: To develop a robust amine chemical exchange saturation transfer (CEST) physical phantom, validate the temporal stability, and create a supporting software for automatic image processing and quality assurance. Materials and methods: The phantom was designed as an assembled laser-cut acrylic rack and 18 vials of phantom solutions, prepared with different pHs, glycine concentrations, and gadolinium concentrations. We evaluated glycine concentrations using ultraviolet absorbance for 70 days and measured the pH, relaxation rates, and CEST contrast for 94 days after preparation. We used Spearman's correlation to determine if glycine degraded over time. Linear regression and Bland–Altman analysis were performed between baseline and follow-up measurements of pH and MRI properties. Results: No degradation of glycine was observed (p > 0.05). The pH and MRI measurements stayed stable for 3 months and showed high consistency across time points (R2 = 1.00 for pH, R1, R2, and CEST contrast), which was further validated by the Bland–Altman plots. Examples of automatically generated reports are provided. Discussion: We designed a physical phantom for amine CEST-MRI, which is easy to assemble and transfer, holds 18 different solutions, and has excellent short-term chemical and MRI stability. We believe this robust phantom will facilitate the development of novel sequences and cross-scanners validations. [ABSTRACT FROM AUTHOR]

Numerous studies have focused on the significance and consequences of teacher judgment; the development of teachers' judgment accuracy over time, however, has been rarely examined. The aim of this study was to investigate the temporal stability of teachers' judgment accuracy of students' motivation, emotion, and achievement. The correspondence between teacher judgments and student characteristics was measured twice within a 4-week period. Nine classes with 326 sixth-graders from a Chinese elementary school and their mathematics teachers took part in the study. Students worked on a standardized mathematics test and a self-description questionnaire for measuring students' motivation and emotion. Teachers judged each student's motivation, emotion, and achievement by single items. Results show that teachers were able to assess student achievement with high accuracy, student motivation with moderate to high accuracy, and student emotion mostly with low accuracy. Teachers' judgment accuracy was highly stable with little changes on different accuracy components. It can be concluded that Chinese elementary school teachers are in a position to make fair judgments about student achievement and student motivation at different times. Student emotions, however, are hard to grasp for teachers. [ABSTRACT FROM AUTHOR]

Biological individuality is a notoriously thorny topic for biologists and philosophers of biology. In this paper we argue that biological individuality presents multiple, interconnected questions for biologists and philosophers that together form a problem agenda. Using a case study of an interdisciplinary research group in ecology, behavioral and evolutionary biology, we claim that a debate on biological individuality that seeks to account for diverse practices in the biological sciences should be broadened to include and give prominence to questions about uniqueness and temporality. We show that broadening the problem agenda of biological individuality draws attention to underrecognized philosophical issues and discussions and thereby organizes and enriches the existing debate. [ABSTRACT FROM AUTHOR]

Individuals of many animal species are said to have a personality. It has been shown that some individuals are bolder than other individuals of the same species, or more sociable or more aggressive. In this paper, we analyse what it means to say that an animal has a personality. We clarify what an animal personality is, that is, its ontology, and how different personality concepts relate to each other, and we examine how personality traits are identified in biological practice. Our analysis shows that biologists often study specific personality traits, such as boldness, sociability or aggressiveness, rather than personalities in general. We claim that personality traits are best understood as dispositions and that they are operationally defined in terms of certain sets of behaviours, which are studied in specific experimental set-ups. Furthermore, we develop an integrative philosophical account that specifies and formalises three criteria for identifying personality traits, which are used in biological practice. For an individual animal to have a personality trait it must, first, behave differently than others (Individual Differences). Second, these behavioural differences must be stable over a certain time (Temporal Stability), and third, they must be consistent in different contexts (Contextual Consistency). [ABSTRACT FROM AUTHOR]

Aims: We quantified the potential influence of arbuscular mycorrhizal fungi (AMF) on primary productivity and community stability and tested whether the effects of AMF depend on soil phosphorus (P) availability and grazing intensity in a semiarid grassland. Methods: We manipulated the abundance of AMF and soil P availability (P addition and no P addition) under four levels of grazing intensity. The aboveground biomass of plant species, functional groups and community, as well as community temporal stability were examined under these conditions. Results: Under no to moderate grazing, benomyl decreased the aboveground biomass in C4 grasses and forbs, but increased the aboveground biomass in C3 grasses under low P conditions; thus no obvious changes in community primary productivity were observed. These results indicated that the mycorrhizal dependency of C4 grasses and forbs is higher than that of C3 grasses under low P conditions. However, community primary productivity was greatly enhanced by benomyl due to the increased biomasses of C3 grasses and forbs under high P conditions. Under heavy grazing conditions, benomyl increased community primary productivity under both low and high P conditions. AMF presence increased the community temporal stability by promoting the compensatory effects between plant species under no to moderate grazing conditions; whereas AMF decreased the community stability by forming a parasitic symbiosis with their plant hosts under heavy grazing conditions. Conclusions: Our findings demonstrate that the effects of benomyl application to suppress AMF on primary productivity and community stability are strongly mediated by soil P availability and grazing intensity, which improves our understanding for the roles of AMF-plant symbiosis on ecosystem functioning in grazed systems. [ABSTRACT FROM AUTHOR]

The ambulatory assessment offers a wide range of methods enabling researchers to investigate psychological, behavioral, emotional, and biological processes. These methods enable us to gather data on individual differences in language use for psychological research. Two studies were conducted with an aim to evaluate and compare the temporal stability of language measures extracted by LIWC software form data obtained by two frequently used methods for assessment of language use, i.e., Electronically Activated Recorder (EAR) and stream of consciousness (SOC) task. Additionally, we examined the amount of variance in language use (assessed by both methods) that can be attributed to intra-individual variability and stable individual differences. Study 1 was focused on investigating language use obtained from 74 respondents using the EAR for 3 consecutive days. Study 2 was conducted on 250 respondents participating in a SOC task where verbal production was collected at ten time points over a 2-month period. Results show that measures obtained using the SOC task have higher temporal stability and consistency, and to a certain extent enable better detection of individual differences. Taking into account certain situational variations improves the reliability of EAR measures. [ABSTRACT FROM AUTHOR]

This paper is devoted to analytical solutions for the base flow and temporal stability of a liquid film driven by gravity over an inclined plane when the fluid rheology is given by the Carreau–Yasuda model, a general description that applies to different types of fluids. In order to obtain the base state and critical conditions for the onset of instabilities, two sets of asymptotic expansions are proposed, from which it is possible to find four new equations describing the reference flow and the phase speed and growth rate of instabilities. These results lead to an equation for the critical Reynolds number, which dictates the conditions for the onset of the instabilities of a falling film. Different from previous works, this paper presents asymptotic solutions for the growth rate, wavelength and celerity of instabilities obtained without supposing a priori the exact fluid rheology, being, therefore, valid for different kinds of fluids. Our findings represent a significant step toward understanding the stability of gravitational flows of non-Newtonian fluids. [ABSTRACT FROM AUTHOR]

To increase reserve farmland resources, ensure food security, and to improve the ecological environment, large-scale gully regulation projects in Yan'an area of the Loess Plateau have been undertaken in China since 2013. Understanding the spatial and temporal distribution characteristics of slope soil moisture during the rainy season is, therefore, important for vegetation selection used in restoration measures in this area. The temporal stability of soil water content in the upper 100 cm soil depth in a gully regulation watershed was examined using six measurements taken during the rainy season (May–November 2016). Temporal stability analysis of the soil water content was undertaken using Spearman's rank correlation coefficient and the relative difference method. Results showed that soil water content in the 0–50 cm and 0–100 cm soil depths demonstrated moderate temporal and spatial variability, and soil water content variability gradually decreased with increasing soil depth. Soil water content in both depths had strong temporal stability, having a positive correlation with soil depth. Furthermore, temporal stability may decrease with increasing soil water content (p < 0.05). The number and position of representative locations were not constant, which varies with the soil depth and the estimation method. Five methods (mean relative difference, minimum relative difference standard equilibrium, temporal stability index, mean absolute deviation and root mean square error) can be used to determine the representative location of temporal stability. However, the prediction accuracy of the soil water content at representative locations obtained using the different methods for mean slope water content differed. Comparatively, the mean absolute deviation method had a higher accuracy, followed by the minimum relative difference standard equilibrium method. Results indicate that the prediction accuracy of five methods increased with soil depth. [ABSTRACT FROM AUTHOR]

Microbial quality of irrigation waters is a substantial food safety factor. Escherichia coli (E. coli) and Enterococci are used as the fecal indicator bacteria (FIB) to assess microbial water quality. Analysis of temporally stable patterns of FIB can facilitate effective monitoring of microbial water quality. The objectives of this study were (1) to investigate the spatiotemporal variation of E. coli and Enterococci concentrations in a large creek traversing diverse land use areas and (2) to explore the presence of temporally stable FIB concentration patterns along the creek. Concentrations of both FIB were measured weekly at five water monitoring locations along the 20-km long creek reach in Pennsylvania at baseflow for three years. The temporal stability was assessed using mean relative deviations of logarithms of FIB concentration from the average across the reach measured at the same time. The Spearman rank correlation coefficients between logarithms of FIB concentrations on consecutive sampling times was another metric used to assess the temporal stability of FIB concentration patterns. Logarithms of FIB concentrations had sinusoidal dependence on time and significantly correlated with temperature at all locations Both FIB exhibited temporal stability of concentrations. The two most downstream locations in urbanized areas tended to have logarithms of concentrations higher than the average along the observation reach. The location in the upstream forested area had mostly lower concentrations (log E. coli 1.59, log Enterococci 1.69) than average (log E. coli 2.07, log Enterococci 2.20). concentrations in colony-forming units (CFU) (100 mL)−1. Two locations in the agricultural and sparsely urbanized area had these logarithm values close to the average. The temporal stability was more pronounced in cold seasons than in warm seasons. No significant difference was found between pattern determined for each of three observation years and for the entire three-year observation period. The Spearman rank correlations between observations on consecutive dates showed moderate to very strong relationships in most cases. Existence of the temporal stability of FIB concentrations in the creek indicates locations that inform about the average logarithm of concentrations or the geometric mean concentrations along the entire observation reach. [ABSTRACT FROM AUTHOR]

Throughfall variability plays a crucial role in regulating hydrological and biogeochemical processes in forest ecosystems. However, throughfall variability and its potential influencing factors remain unclear in the subtropical deciduous forest because of its complex canopy and meteorological conditions. Here, the spatial variability and temporal stability of throughfall were investigated from October 2016 to December 2017 within a deciduous forest in the subtropical hilly regions of eastern China, and the effects of meteorological variables and distance from nearest tree trunk on throughfall variability were systematically evaluated. Throughfall variability during the leafed period was slightly higher than that during the leafless period inferred from the coefficient of variation of throughfall amounts (CVTF), with 13.2%–40.9% and 18.7%–31.9%, respectively. The multiple regression model analysis suggested that the controlling factors of throughfall variability were different in studied periods: Maximum 10-min rainfall intensity, wind speed and air temperature were the dominant influencing factors on throughfall variability during the leafed period, with the relative contribution ratio (RCR) of 25.9%, 18.7% and 8.9%, respectively. By contrast, throughfall variability was affected mainly by the mean rainfall intensity (RCR=40.8%) during the leafless period. The temporal stability plots and geostatistical analysis indicated that spatial patterns of throughfall were stable and similar among rainfall events. Our findings highlight the important role of various meteorological factors in throughfall variability and are expected to contribute to the accurate assessment of throughfall, soil water and runoff within the subtropical forests. [ABSTRACT FROM AUTHOR]

In this paper, a stable node-based smoothed finite element method (SNS-FEM) is presented for analyzing metal forming problems using linear triangular or tetrahedral elements. In present method, the numerical integration domains are approximately circular or spherical regions of the node-based smoothing domains generated by the node-based smoothed finite element method (NS-FEM). Four or six supplementary integration points, which are symmetrically located at the crossover points of the region and the coordinate axis, are employed for each node to form the stabilization items associated with the variance of smoothed shape function gradient. Through this operation without the introducing of any uncertain parameter, the SNS-FEM not only significantly cures the temporal instability of NS-FEM but also performs better in effectiveness and efficiency than FEM, which is well validated by several numerical examples containing benchmark cases. Additionally, a simple but effective contact algorithm including contact searching and contact force computation is presented. [ABSTRACT FROM AUTHOR]

Numerous studies have identified individually distinctive vocal characteristics and call consistency in different bird species. If these vocal characteristics are to be utilised as non-invasive markers for monitoring purposes, then they must remain stable over time. Three recent studies have shown that it is possible to identify individual male Common Cuckoos (Cuculus canorus) based on vocal characteristics, but whether these characteristics are stable over the duration of a breeding season remains unknown. We recorded 1032 syllables from 30 male Common Cuckoos in a Northeast Asian population. We banded six of these males and made repeated recordings of their cu-coo advertisement call across a 19-day period of the breeding season in China. We used three methods to identify individuals: discriminant function analyses (DFA), correlation analysis (CA) and spectrographic cross-correlation (SPCC). We also used repeatability analysis to test whether call consistency (the number of syllables in each calling bout) was repeatable within individuals. Based on the same-day recordings, calls from the same male were more similar in their characteristics than compared to those of different males, and yielded correct rates of classifying individuals of 93.6% (SPCC), 90.8% (DFA), and 71.5% (CA). However, these rates declined to 40.5% (SPCC), 40.7% (DFA) and 27% (CA) when using recordings over the 19-day period. Call consistency was repeatable within individuals across two successive calling bouts, but this individual repeatability disappeared when several (more than two) calling bouts from the same day or bouts from the different days of the study were included in the analyses. Declines in the correct rate of identifying individual male cuckoos and call consistency in this study raise concerns that individual male cuckoo calls may be more variable than previously thought. [ABSTRACT FROM AUTHOR]

Purpose: Information on root-zone soil water content (SWC) is essential for vegetation restoration, irrigation scheduling, and hydrological modeling. However, measurements of SWC within a variety of land uses may be time-consuming and labor-costing. This study tested whether SWC at a depth of a land use can be used to predict profile SWC of other land uses in terms of temporal stability analysis at a karst depression area in southwest China.Materials and methods: A total of 30 datasets of root-zone SWC from 0.1- to 0.5-m depths were collected by time domain reflectometry probes for three typical land uses from March 12 to November 8, 2015.Results and discussion: Results showed that the profile mean SWC and its associated standard deviation (SDP) and coefficient of variation (CVP) differed significantly (P < 0.05) among the grassland, farmland, and forestland. The profile SWC was more temporally stable according to the apparently lower CVT in comparison with CVP. The similarities of the vertical patterns of SWC were strong for the same land uses, while were relatively weak between the different land uses. The SWC measurements of the most temporally stable depth can be used to accurately predict profile SWC for both the same land use and other land uses.Conclusions: This study further expands the application of the temporal stability analysis and can aid water resource management in areas with diverse land uses. [ABSTRACT FROM AUTHOR]

Accurate estimates of soil moisture and soil hydraulic parameters via data assimilation largely depend on the quality of the model structure, input data and observations. Often, however, all of this information is subject to uncertainty under real circumstances. This real-case study seeks to understand the effects of different uncertainty sources and observation scales on data assimilation performance. Ensemble Kalman filter method based on the soil water-flow model, a sub-module of soil-water-atmosphere-plant model, is established to simultaneously estimate the model states and parameters. The soil hydraulic parameters are extensively measured or calibrated to examine the parameter estimation accuracy. Furthermore, considering the high spatial and temporal variability of soil moisture observation in the field-scale problem, an analysis of spatiotemporal characteristics is combined with data assimilation. Results indicated that simultaneously considering parameter and initial conditions uncertainty leads to a better soil moisture and parameter estimation than that ignoring initial uncertainty in realistic practice. Unlike the other error sources, an inadequate description to the meteorological forcing has a negative influence on surface soil moisture estimation, which might be attributed to the persistent disturbances of evaporation uncertainty and the lack of observations at shallow soil depth. Moreover, a prior knowledge of spatiotemporal features of soil moisture observation is beneficial to efficiently improve data assimilation performance. It is possible to implement field-scale data assimilation with a few representative points, instead of using the spatial average of all observations at a high cost. The assimilation results highlight the possibly positive outcomes of accounting for the multi-source of uncertainties and emphasize the significant importance of characterizing the spatial-temporal feature of soil moisture for a field-scale application. [ABSTRACT FROM AUTHOR]

In order to protect biodiversity, conservation genetics are of great importance. Until now, a few population genetic studies of Neotropical bumblebees are available but studies of temporal stability in genetic diversity are lacking. Here, genetic variability of three South Brazilian species Bombus bellicosus, B. pauloensis, and B. morio was investigated over time. Hereto, museum collection specimens of 1946 until 2012, from eight locations in Rio Grande do Sul, were genotyped at 16 microsatellite loci. During an additional sampling in the foraging season of 2015, no bumblebees could be collected possibly due to the super El Niño of 2015-2016. Our results on the collection specimens demonstrated a significantly higher genetic diversity in B. morio than in B. pauloensis. Genetic variability in B. pauloensis gradually and significantly decreased over time from 1946 until 2012; while in B. morio, genetic variability remained stable until the last time period (2010-2012). For B. bellicosus, not enough data was available. Although the studied populations became more vulnerable over time, for the conservation of Neotropical bumblebees, still more information is needed and could include more frequent monitoring of bumblebees. Adding B. bellicosus to the Brazilian list of threatened species is suggested. [ABSTRACT FROM AUTHOR]

The stability of the Poiseuille flow in a channel with longitudinal comb grooves on the lower wall is studied numerically. Dependences of the linear and energy critical Reynolds numbers on the groove spacing and height are obtained and analyzed. The results are compared with data available for wavy grooves, which tend to comb grooves as one of the groove parameters approaches infinity. [ABSTRACT FROM AUTHOR]

We evaluate the temporal stability of willingness-to-pay values obtained from two identical stated-preference surveys undertaken in 2004 and 2012. The surveys employ two discrete-choice elicitation formats to value reductions in two health endpoints related to tap water consumption, and are explicitly designed to make direct comparisons between formats. We find no significant differences in real willingness-to-pay between the two surveys for either format-a result that is robust to the structure of heterogeneity used to model respondent preferences. Findings lend support, at least within the context of tap water quality, to the temporal transfer of nonmarket benefits over extended time periods. [ABSTRACT FROM AUTHOR]

The water availability relies primarily on precipitation whose spatial and temporal variability depends on meteorological and topographic attributes. Water becomes a precious natural resource, especially in semiarid areas. Generally, decisions on water resources are made on the whole watershed, but the variability of precipitation is related to topography. The work was aimed at quantifying the spatial variability of annual precipitation for a 40-year-long time series in the Macta basin (Algeria) by using a geostatistical approach and to detect the temporal stability of dry areas. To assess if annual precipitation variability could depend upon the elevation, the study area was divided into five geographical units (polygons) based on elevation and polygon kriging was applied. For each hydrologic year, the standardized relative difference of precipitation (SRDP) was evaluated and dry areas identified. The temporal stability of SRDP with elevation was assessed using the Spearman rank coefficient. Geostatistical approach showed different variability structures of annual precipitation over the considered period. Results highlighted differences in SRDP within the geographical units located at different elevation and the non-stability of dry periods with time within the same polygon. A remarkable dry tendency was assessed in the northern polygon, while the polygons at higher elevations were dominated by temporal instability. The spatio-temporal non-stability of dry areas might be attributed to the change in general atmospheric circulation in North Africa over the last decades and to the nonlinear interaction among precipitation and orography. The identification of dry areas can help decision-makers to plan management and conservation programs in Algeria. [ABSTRACT FROM AUTHOR]

The general objectives of this study were to evaluate (i) the specificity of the spatial and temporal dynamics of apparent soil electrical conductivity (EC) measured by a electromagnetic induction (EMI) sensor, over 7 years, in variable conditions (of soil moisture content (SMC), soil vegetation cover and grazing management) and, consequently, (ii) the potential for implementing site-specific management (SSM). The DUALEM 1S sensor was used to measure the EC in a 6 ha pasture experimental field four times between June 2007 and February of 2013. Soil spatial variability was characterized by 76 samples, geo-referenced with the global positioning system (GPS). The soil was characterized in terms of texture, moisture content, pH, organic matter content, nitrogen, phosphorus and potassium. This study shows a significant temporal stability of the EC patterns under several conditions, behavior that is an excellent indicator of reliability of this tool to survey spatial soil variability and to delineate potential site-specific management zones (SSMZ). Significant correlations were obtained in this work between the EC and relative field elevation, pH, silt and soil moisture content. These results open perspectives for using the EMI sensor as an indicator of SMC in irrigation management and of needs of limestone correction in Mediterranean pastures. However, it is interesting to extend the findings to other types of soil to verify the origin of the lack of correlation between the EC data measured by DUALEM sensor and properties such as the clay, organic matter or phosphorus soil content, fundamental parameters for establishment of pasture SSM projects. [ABSTRACT FROM AUTHOR]

Conservation of threatened or endangered species in a hybrid zone requires a comprehensive understanding of interspecific dynamics over time and space. We evaluated changes in location and composition of a hybrid zone over a 15-year period (with replicated sampling in 1997-2000 and 2011-2013) for saltmarsh ( Ammodramus caudacutus) and Nelson's ( A. nelsoni) sparrows, two tidal marsh specialists of high conservation priority in the northeastern United States. We combined genetic analyses using microsatellite and mitochondrial markers with species distribution patterns. In both time periods, replicate genetic sampling ( n = 85; five sites) and field population surveys (93 sites) were conducted. We compared the distribution of parental species and hybrids and estimates for hybrid zone width and center between the two time periods. An increase in the relative proportion of Nelson's sparrows in sympatric marshes and an approximate doubling of hybrid zone width provides evidence for expansion. Introgression rates increased over time for neutral loci but declined for a mitochondrial gene and two gene-associated loci under the influence of selection, as expected under a speciation model with barriers to gene flow. On average, the center of the hybrid zone shifted 60 km southward over the 15 years. We placed our findings within a policy framework to evaluate management options for hybrids. We conclude that despite increasing rates of introgression, hybridization poses a substantially lesser threat to parental populations than the imminent consequences of sea-level rise and habitat degradation. Based on our current knowledge of hybrid zone dynamics in this system, we conclude that the conservation of hybrids is warranted along with parental species at this time. [ABSTRACT FROM AUTHOR]

The length-age distributions and genetic variation of ten microsatellite loci were examined in samples of herring from the Chupa Inlet of the Kandalaksha Gulf of the White Sea. The samples were collected on the same spawning grounds over a period of 13 years and during the same spawning season. The obtained data demonstrate stability of the length structure and genetic characteristics (allele and genotype frequencies, allelic richness, and heterozygosity). The degree of temporal genetic differentiation was not statistically significant, θ = 0.0038 (CI,-0.0006 to 0.006). Spatial differentiation of the White Sea herring far outweighs the level of temporal variability, which makes it possible to suggest the important role of reproductive isolation in the formation of the population genetic structure of herring. [ABSTRACT FROM AUTHOR]

Knowledge of the temporal variability of soil water content (SWC) at the hillslope scale is essential for guiding rehabilitation strategies and for optimizing water resource management in the karst region of southwest China. This study aimed to use temporal stability analysis to upscale point-scale measurements to represent mean areal SWC on two typical karst hillslopes. Based on a grid sampling scheme (10 m × 10 m) applied to two 90 m × 120 m plots located on two hillslops, the SWC at a depth of 0-16 cm was measured 11-12 times across 259 sampling points, using time domain reflectometry (TDR) from April 2011 to October 2012. Soil texture, bulk density (BD), saturated hydraulic conductivity ( K ), organic carbon (SOC), rock fragment content (RFC), and site elevation (SE) were also measured at these locations. Results showed the hillslope with more shrub cover was wetter than the hillslope with mixed grass-shrub cover. This difference was related to the differences in soil texture, soil hydraulic permeability, and topography. Through a comparison of values obtained with the Spearman correlation coefficient ( r ), standard deviation of mean relative difference (SDRD), and mean absolute bias error (MABE), we inferred that there is a higher degree of temporal stability for SWC in wet conditions than in drier conditions on the two hillslopes. Based on the values of the index of temporal stability (ITS), which combine the mean relative difference (MRD) and SDRD, the two locations were determined to be representative of mean SWC on both hillslopes. Moreover, these locations captured changes in mean SWC (NSCE = 0.69, and 0.65, and RMSE = 1.96, and 1.96 %, respectively). This demonstrates the feasibility of using the temporal stability of SWC to acquire mean SWC on karst hillslopes of southwestern China. The indirect method, which estimates mean SWC by considering the offset between the mean and the measurement value at a time-stable location, predicted mean SWC (NSCE = 0.86, and 0.76, and RMSE = 1.29, and 1.63 %, respectively) more precisely than the direct method (mean SWC directly measured at a time-stable location), because it eliminates deviation by introducing a constant offset (MRD). We recommended the use of the indirect method to acquire mean SWC values, when an allowable bias of 5 % for both MRD and SDRD can not be achieved. In addition, we found that soil texture, RFC, and elevation affect the pattern of SWC on the shrub hillslope. These results are expected to be useful for monitoring soil water dynamics on karst hillslopes, especially for restoration purposes. [ABSTRACT FROM AUTHOR]

Background: We compare the climate sensitivity of European beech ( Fagus sylvatica L.) in two forest nature reserves in northeastern Germany. The one reserve, Schlossberg, is characterized by shallow chalk soils, whereas in the other reserve, Eldena, soils are deeper and more developed. Little is known about the drought sensitivity of beech on shallow chalk soils. Methods: We collected increment cores at both research sites and established climate-growth relationships. Inter-tree variability was assessed by employing linear mixed-effect models. Results: We expected to find distinctively higher drought sensitivity at Schlossberg due to limited water availability, but find only marginal differences in growth responses. At both sites, drought is the major climatic factor driving tree growth. Adaptations in tree architecture and an underestimation of the water holding capacity of shallow chalk soils are discussed as possible reasons for not finding more distinct climate responses. In analyzing climate-growth relationships, we specifically focused on growth responses of individual trees but observed only low inter-tree variability at both sites. Evident is a shift in climate response patterns from the first to the second half of the twentieth century with previous-year drought conditions becoming more important than current-year drought. This shift is discussed in relation to a warming trend over that same period, as well as possible trends in masting behavior of beech. Conclusion: The investigated beech trees on the shallow chalk soil are only slightly more drought sensitive than beech trees on the reference site with deeper and more developed soils. [ABSTRACT FROM AUTHOR]

A dispersion equation for studying the relation between temporal and spatial stability of a liquid jet containing vapor bubbles in coaxial swirling compressible flow is presented by the use of two linear theories, temporal theory and spatial theory. The mathematical model and the corresponding solving methods to the two linear theories are verified by comparing with the data in the literature. Furthermore, the relation between temporal and spatial stability of a liquid jet containing vapor bubbles is investigated, and the effects of the gas rotational strength, the gas Mach number and the bubble volume fraction on the difference between temporal and spatial stability are then discussed. Some conclusions can be drawn from the results of this investigation, for a liquid jet with the given physical parameters, (1) there are no significant differences between temporal theory and spatial theory in respect of the dominant mode of disturbance on the jet surface, the dominant characteristic wave frequency and the smallest atomized droplet, (2) the interfacial disturbance amplitude with spatial theory is apparently larger than the disturbance amplitude with temporal theory, (3) the coaxial rotation of the surrounding gas is a factor to affect the difference between temporal and spatial theory, and there is a certain value of the non-dimensional gas rotational strength ( E = 1.5) which makes the difference between the two linear theories reach the peak, (4) the effect of the gas compressibility is to increase the difference between temporal and spatial theory, and the effect of the gas compressibility is going to increase rapidly when the gas Mach number Ma ≥ 0.5, and (5) the effect of bubble volume fraction is to increase the difference between temporal and spatial theory, and the difference value is approximately proportional to the increasing of bubble volume fraction. [ABSTRACT FROM AUTHOR]

Soil organic carbon (SOC) plays a vital role in determining the susceptibility to land degradation. The recommended procedure for the recovery of the characteristic poor soils of the Southern region of Portugal is the installation of grazed permanent pastures and increase of soil fertility. The objectives of this study were: (i) to identify the spatial and temporal patterns of soil nutrients at four points in time over a 10-year period in a perennial pastureland; (ii) to test new tools for survey of the spatial variability of soil nutrients; (iii) to evaluate the potential for differential organic management. A 6 ha permanent bio-diverse pasture field, grazed by sheep and improved by annual application of super phosphate fertilizer, was installed on a shallow soil in Mediterranean conditions. Spatial variability and temporal stability of topsoil macronutrients (phosphorus, nitrogen and potassium), SOC and pH were measured. The results indicate that SOC and pH have great potential for implementing differential management. In the case of SOC, the management classes map shows that over 80 % of the area has temporal stability, while more than 50 % of the area has low levels of SOC (<10 g kg), justifying the potential for differential application of C-rich organic soil amendments. The geospatial measurements of apparent soil electrical conductivity (EC) and NDVI index showed significant correlation between these parameters and soil properties, revealing the potential of these tools for producing detailed soil maps, decisive for understanding the changes in soil properties under sustainable management systems. [ABSTRACT FROM AUTHOR]

The “Grain for Green” Project on the Loess Plateau of China has converted a large area of cultivated slope farmland to terraces to reduce soil erosion and improve the ecological environment. The area of terraced land on the Loess Plateau was 32,600 km2 in 2010. Knowledge of the behavior of soil water storage (SWS) and its spatiotemporal distribution provides essential information concerning hydrological and ecological processes. This study aimed to analyze the temporal stability of SWS after rainfall for different time periods on terraces planted with jujube trees (Ziziphus jujuba Mill.). The SWS of 21 locations was obtained from July 19 to September 3 in 2014 and from August 01 to August 31 in 2015. Relative difference analysis and the nonparametric Spearman rank correlation test were used to check the temporal stability of SWS. The SWS on terraces was normally distributed and demonstrated moderate spatial variability. The SWS at three soil depths all showed strong temporal stability with stability in the order of 0–0.6 < 0–1.0 < 0–1.6 m. Rainfall significantly affected the temporal stability of SWS in the depth of 0–0.6 m. The number of representative locations of SWS was not constant. The best representative locations were not identical for different soil depths; however, a common representative location did exist for the different depths and periods. Moreover, the mean SWS generally increased from the upper to lower slope. The temporal stability of SWS was not significantly affected by rainfall but was significantly negatively correlated with sand content. The total root length and soil organic carbon content did not show any obvious correlations with mean SWS. It was feasible to use the representative locations of SWS to represent the mean SWS over a period of time. However, the cumulative absolute error increased with cumulative days. In conclusion, SWS in the deeper soil depths indicated greater temporal stability than that in shallow soil depth during wet period. The best representative locations for SWS were depth and time dependent. [ABSTRACT FROM AUTHOR]

Larval dispersal and limited knowledge of physical boundaries challenge our understanding of the processes that drive genetic divergence and potential speciation in the marine environment. Divergence, both within and between populations of marine taxa, is not uncommon, but spatial and temporal stability of observed genetic structure is not well known. Previously, we detected large genetic differences among populations of the cardinalfish species Ostorhinchus doederleini inhabiting adjacent coral reefs. Here, we determined the spatial and temporal persistence of these genetic structures over the course of ten consecutive generations. Using microsatellite markers, we detected large changes (genetic population distance, D, ranged from 0.04 to 0.46) in the genetic structure in some years, but some reefs maintained the same populations for nearly all sampling years. As this species' life span does not exceed 1 yr, persistence of distinct reef populations suggests natal homing. Mitochondrial identity based on two mtDNA markers corroborates the nuclear genetic evidence for genetic differences large enough to constitute different clades and even cryptic species in O. doederleini, which, based on gross morphology, was thought to be a single taxon. Habitat specialization was observed in one clade that exclusively inhabited reef lagoons, while all clades could be observed on reef slopes. We suggest that local habitat recognition combined with local population recognition and selection against hybrids can form barriers that maintain a cryptic species complex. [ABSTRACT FROM AUTHOR]

In arid and semi-arid regions, soil moisture in particular is a key integrative state variable that is linked to a range of hydrological, ecological, climatic, and geological processes; however, it is usually highly variable in space and time. To overcome this issue, it is necessary to study the temporal stability of soil moisture. Here, we intend to take a soil moisture temporary stability analysis for the typical hilly and gully re-vegetated areas in the Loess Plateau. Using cumulative frequency distribution, the relative difference, and Spearman’s rank correlation coefficient to conduct temporal stability analysis for the soil moisture at five slope transects of a typical hilly and gully re-vegetated loess catchment during the rainy season of 2012. We found the soil moisture spatial distribution pattern for the small, typical hilly and gully re-vegetated Loess Plateau catchment to be stable. However, it is not always easy to find sites representative of the catchment average moisture content under different conditions; but it is easier to find sites with extremely high water content in the slopes. A new method for identifying temporally stable locations in typical re-vegetated hilly and gully loess areas is needed. The relationships between soil moisture and other catchment conditions for the diagnosis of representative sites must also be determined. The pattern stability and type stability of soil moisture guarantees that sampling comparisons in this area can be conducted at different times to compare the differences between various land cover types, especially with regard to deep soil depth. [ABSTRACT FROM AUTHOR]

Temporal stability of soil water storage (TSSWS) is of considerable interest in estimating the mean soil water storage (SWS) across the study area for validating the remote sensing products and reducing the observation efforts. However, the general mean relative difference index usually balances the positive and negative relative difference values. Thus, it may find the weakly representative site for mean SWS estimation. Revised mean relative difference, i.e., the absolute value of general relative difference, was used in two deposited soil farmlands (DFs) to analyze the TSSWS. The soil water contents were measured at 18 sites of each DF in 1.5 years. The results showed that revised mean relative difference index was more accurate than normal one in finding the best location to represent mean SWS in the DFs. This can be applicable to sites where SWS is not consistently higher or less than the average value. The SWS in the location which was near to the middle DF showed the strongest temporal stability and behaved the best location to estimate the mean SWS. Revised mean relative difference may be a better criterion for the application of temporal stability tool in soil water field observation. [ABSTRACT FROM AUTHOR]

Knowledge of soil moisture temporal stability and its controlling factors is important for hydrological and environmental management decisions. This study analyzed the influences of soil and terrain on soil moisture temporal stability (relative difference of soil moisture- δ and standard deviation of δ − S) on two contrasting land use hillslopes [tea garden (TG) and bamboo forest (BF)] in the hilly area of Taihu Lake Basin, China. Soil moisture temporal stabilities were considered at two depths (0.1 and 0.3 m) and during eight different periods (entire, dry, wet, rain, spring, summer, fall and winter periods). Results showed that for each land use and soil depth, values of δ in summer were largely deviated from those during the entire period, while values of S after rain storms were strongly deviated from those during the entire period. Correlation coefficients between soil/terrain and δ were generally greater on the BF hillslope (ranged from 0.35 to 0.70) than on the TG hillslope (ranged from 0.30 to 0.55). This suggested that soil moisture distribution was more spatially organized on the BF hillslope than on the TG hillslope. This can be attributed to that the management practices disturbed and mixed the soils on the TG hillslope, which made the soil moisture more randomly distributed. The controls on S substantially varied with season, soil depth and land use. On the TG hillslope, soil/terrain had weak correlations with S, while on the BF hillslope, rock fragment, slope and elevation had decent correlation with S. This varied controlling factors of S on different hillslopes, period and soil depth suggested that spatial distributions of S were influenced by the occurrence of subsurface preferential flow. Findings of this study suggested that soil moisture temporal stability and its controlling factors were land use type and time period dependent. [ABSTRACT FROM AUTHOR]

Temporal stability of soil moisture has important implications for optimal and effective field monitoring and has been observed for a range of soil and landscape conditions. However, relatively less is known about temporal stability of soil moisture in desert areas. In this study, two 5-km transects (TranA and TranB) with different soil properties in a desert area of northwestern China were chosen to assess the characteristics of the temporal variability and stability of soil moisture, to identify representative sampling locations (RSLs), and to evaluate the effect of sampling frequency on the determination of temporal stability. For each transect, moisture contents of the surface soil were measured using Theta Probes on 35 occasions at 51 locations from April to October 2012. The results showed that soil moisture for the finer-textured TranA was consistently higher and more variable than for the coarser-textured TranB. Both transects exhibited strong temporal stability during the monitoring period. Locations with higher sand contents tended to have more pronounced temporal stabilities. The RSL identified in each transect accurately represented the mean moisture contents of the transects over time, with coefficients of determination ( R) higher than 0.95 and root mean square errors lower than 1 % vol/vol. Soil moisture has significantly higher degrees of temporal stability during dry periods than during wet periods. The effect of sampling frequency on temporal stability of soil moisture was not as evident, particularly for the coarser-textured soil. This study provides insights for designing strategies for the sampling and monitoring of soil moisture in the hydrological applications in desert areas. [ABSTRACT FROM AUTHOR]