Morphodynamic modelling of dryland non-perennial riverscapes, with implications for environmental water allocation

2021 ◽  
pp. 030913332199663
Author(s):  
MC Grenfell ◽  
SE Grenfell ◽  
D Mazvimavi
Keyword(s):  
Water Allocation ◽  
Dynamic Range ◽  
Temporal Dynamics ◽  
Growth Models ◽  
Environmental Water ◽  
Habitat Associations ◽  
Rate Of Change ◽  
Physical Habitat ◽  
Morphodynamic Modelling ◽  
Testing Field

Reach-scale river restoration or environmental water allocation (EWA) exercises typically address the magnitude and temporal dynamics (frequency, duration, timing, rate of change) of flows required to sustain desirable ecological conditions along a river. The role of geomorphology in this process is to broaden the gaze beyond flows to consider larger and longer-term interactions between valley lithological structure, and the feed and fate of flow-sediment mixtures. This paper proposes the integration of numerical morphodynamic modelling in evaluations of environmental water requirements for non-perennial riverscapes (channel–riparian–floodplain environments). The paper presents a methodological framework, and proof of concept case study from the Touws River, South Africa, for the application of morphodynamic modelling in EWA. The paper illustrates operational approaches to modelling the complexity of dryland mixed bedrock-alluvial (and mixed-load) riverscapes with highly variable non-perennial flow regimes, including an approach to generating initial bed conditions for numerical experiments by ‘morphodynamic spin-up’, and approaches to synthesising and presenting numerical experiment output in the form of a dynamic range of potential variability in metrics of physical habitat suitability and diversity, and disturbance/renewal regimes. Such efforts can assist in enhancing field observations and testing field-based hypotheses of flow-sediment regime–physical habitat associations, extending the timescales of analysis beyond field observation, and constraining uncertainty about the dynamic range of variability in responses to predicted future flow-sediment regime modifications. Further research is needed to develop growth models appropriate for key non-perennial river vegetation types, to support biomorphodynamic modelling of geomorphology–vegetation interactions, and to determine or predict appropriate inlet sediment concentrations for historical and future modification scenarios.

scholarly journals Growth Models of Positive Caregiving Behaviours and Concurrent Autonomic 
Activity in Caregivers and Children during a Challenging Puzzle Task: Replication and Extension

2020 ◽  
Author(s):  
Heidi Barkman ◽  
Ashley Allan ◽  
Marlee Salsbury ◽  
Erik L Knight ◽  
Christina Karns ◽  
...  
Keyword(s):  
Nervous System ◽  
Parasympathetic Nervous System ◽  
Dynamic Range ◽  
Growth Models ◽  
Multilevel Modelling ◽  
Emotional Expressions ◽  
Parasympathetic Nervous System Activity ◽  
Low Levels ◽  
Positive Caregiving ◽  
Puzzle Task

Caregivers exhibiting low levels of positive caregiving tend to have reduced dynamic range in high- frequency heart rate variability (HRV), an index of parasympathetic nervous system activity. Yet less is known about the involvement of the sympathetic nervous system, which may impact the plausible range of parasympathetic reactivity. Here, caregiver–child dyads completed resting assessments of HRV and pre-ejection period (PEP), followed by a videotaped puzzle task during which HRV was measured and observers coded the degree of caregivers’ positive emotionality. Multilevel modelling was employed to characterize task fluctuations in HRV as a function of resting PEP and caregivers’ positive emotional expressions. Higher frequency of caregiver positivity was associated with greater HRV reactivity in caregivers but not children. Increased caregiver positivity was correlated with longer resting PEP in children. These results replicate findings of greater caregiver parasympathetic flexibility during positive caregiving and extend those findings to children’s resting sympathetic activity.

Jellyfish distribution and abundance in relation to the physical habitat of Jellyfish Lake, Palau

2018 ◽  
Vol 34 (1) ◽  
pp. 17-31 ◽  
Author(s):  
Megan A. Cimino ◽  
Sharon Patris ◽  
Gerda Ucharm ◽  
Lori J. Bell ◽  
Eric Terrill
Keyword(s):  
Autonomous Underwater Vehicle ◽  
Size Fraction ◽  
Underwater Vehicle ◽  
Habitat Associations ◽  
Physical Habitat ◽  
Uv Damage ◽  
Tourist Destination ◽  
Novel Approach ◽  
Abundance Estimates ◽  
Acoustic Surveys

Abstract:Animals often select for habitats that increase their chance of survival by balancing the need to acquire food, reproduce and avoid predation. Perennial blooms of golden jellyfish (Mastigias papua etpisoni) are present in Jellyfish Lake, Palau, a popular tourist destination. Based on the species’ economic importance and unusual behavioural complexity, increased understanding of jellyfish habitat selection is necessary. We used a novel approach, a REMUS autonomous underwater vehicle, to quantify jellyfish distribution, abundance and habitat, and compared these findings to traditional methods. Midday acoustic surveys showed jellyfish distribution was patchy and the population resided mainly on the eastern side of the lake, as it is known that jellyfish migrate eastward towards the sun. Highest vertical densities of jellyfish were at 6–7 m, potentially to mitigate UV damage or photoinhibition of their photosymbionts, suggesting a coupling exists between their vertical distribution and water properties. Abundance estimates of jellyfish were ~2.75 and ~7.1 million (~2 million excluding bell diameters <1 cm) from acoustic and net samples, suggesting the methodology employed underestimated the population's smaller size fraction and non-synoptic surveys could impact estimates due to unresolved patchiness. Our approach could investigate population dynamics, behaviour or habitat associations on fine scales.

scholarly journals The Role of Coping Strategies in Maintaining Well-Being During the COVID-19 Outbreak in South Korea

2021 ◽  
pp. 194855062199059
Author(s):  
Joo Hyun Kim ◽  
Yerin Shim ◽  
Incheol Choi ◽  
Eunsoo Choi
Keyword(s):  
South Korea ◽  
Coping Strategies ◽  
Growth Models ◽  
Phase 1 ◽  
Well Being ◽  
Rate Of Change ◽  
Phase 2 ◽  
Behavioral Strategies ◽  
The Individual

The COVID-19 pandemic continues to pose an unprecedented challenge for the world as people strive to cope with this significant threat to their well-being. This intensive longitudinal study of the first 94 days of the COVID-19 outbreak in South Korea (Phase 1: initial outbreak, Phase 2: intense social distancing) examined individuals’ changes in well-being, in relation to their use of coping strategies and fear of infection. A sample of 10,464 South Koreans participated in surveys during Phase 1 and Phase 2, resulting in 35,846 observations. Multilevel growth models revealed a decrease in well-being while different coping strategies moderated the individual rate of change in well-being. Although preventive measures were associated with a greater decrease in well-being, cognitive appraisal and behavioral strategies predicted stable well-being during the pandemic. Coping strategies further mediated the association between fear of infection and deterioration of well-being.

Economic and Ecological Benefits on the Implementation of Integrated Water Allocation in the Yellow River

2012 ◽  
Vol 212-213 ◽  
pp. 560-563
Author(s):  
Chen Guang Xu ◽  
Mai Huan Zhao ◽  
Li Yuan He
Keyword(s):  
Water Consumption ◽  
Water Allocation ◽  
Yellow River ◽  
Yellow River Basin ◽  
Environmental Water ◽  
Base Flow ◽  
The Yellow River ◽  
Healthy Life ◽  
Ecological Benefits ◽  
The Yellow River Basin

Integrated water allocation in the Yellow River has played an important role in maintaining the healthy life of the Yellow River and realizing its functionally unabated flow. After the integrated water allocation, the average surface water consumption in the Yellow River Basin decreased 46*108 m3, the average annual benefits reached 12.643 billion Yuan, and the GDP accumulatively increased 3504*108 Yuan. The Yellow River has flowed unabated for 10 successive years, and the eco-environmental water consumption in the lower reaches during the non-flood season has increased 14.6*108 m3, which guaranteed the base flow of the Yellow River

scholarly journals Introducing an Environmental Microbiome to Axenic Insectary Reared Mosquitoes Alters Host and Microbe Blood Digestion Phenotypes

2021 ◽  
Author(s):  
Blaire Steven ◽  
Jacquelyn LaReau ◽  
Josephine Hyde ◽  
Doug Brackney
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
Blood Meal ◽  
Temporal Dynamics ◽  
Sequence Data ◽  
16S Rrna Gene Sequencing ◽  
Water Source ◽  
Environmental Water ◽  
Rrna Gene ◽  
Blood Digestion

Abstract The microbiota of Aedes aegypti has been the subject of much research due to the potential role of the microbiome in mosquito physiology, development, and vectorial capacity. Axenic mosquitoes were colonized with environmental bacteria to compare microbiota acquired from the environment to insectary reared counterparts, particularly regarding blood meal digestion. Observationally, environmentally colonized mosquitoes showed faster blood digestion than insectary mosquitoes. 16S rRNA gene sequencing revealed that the diversity and community structure of the midgut microbiomes were distinct between the groups, with the environmental microbiomes having a greater diversity and larger temporal dynamics over the course of the blood meal. Metagenomic prediction from the 16S rRNA gene sequence data pointed to functional genes such as hemolysins differing between the two microbiomes. Additionally, only bacteria cultured from the environmental mosquitoes demonstrated hemolytic ability. Presence of these hemolytic bacteria may explain the observations of differing blood digestion rates in the mosquito. These data show that microbiomes of mosquitoes colonized from an environmental water source differ taxonomically and functionally from those from the insectary, with potential influences on host blood digestion. Thus, the axenic mosquito model can be employed to interrogate various microbiome compositions and link them to phenotypic outcomes of the host.

Issues in environmental water allocation – an Australian perspective

2003 ◽  
Vol 48 (7) ◽  
pp. 83-88 ◽  
Author(s):  
N. Schofield ◽  
A. Burt
Keyword(s):  
Social Sciences ◽  
Policy Development ◽  
Water Allocation ◽  
Environmental Water ◽  
Critical Issue ◽  
Current Understanding ◽  
Water Requirements ◽  
Law And Policy ◽  
Future Needs ◽  
Scientific Advances

Environmental water allocation is a critical issue in Australia and internationally. It has been prominent in Australia for a little over ten years during which time major policy and scientific advances have been made, but little implementation. This paper examines current understanding of environmental water allocation across a broad range of disciplines including the biophysical sciences, social sciences, economics, law, and policy. Development of practical methods for assessing environmental water requirements and experience with implementation in Australia are discussed. The paper concludes with thoughts on future needs.

Saproxylic beetles in disturbed boreal forests: Temporal dynamics, habitat associations, and community structure

Ecoscience ◽  
2012 ◽  
Vol 19 (4) ◽  
pp. 328-343 ◽  
Author(s):  
Jonathan Boucher ◽  
Ermias T. Azeria ◽  
Jacques Ibarzabal ◽  
Christian Hébert
Keyword(s):  
Community Structure ◽  
Boreal Forests ◽  
Temporal Dynamics ◽  
Habitat Associations ◽  
Saproxylic Beetles

Age is no kinder to the better educated: absence of an association investigated using latent growth techniques in a community sample

2001 ◽  
Vol 31 (1) ◽  
pp. 15-28 ◽  
Author(s):  
H. CHRISTENSEN ◽  
S. M. HOFER ◽  
A. J. MACKINNON ◽  
A. E. KORTEN ◽  
A. F. JORM ◽  
...  
Keyword(s):  
Cognitive Decline ◽  
Growth Models ◽  
Cognitive Change ◽  
Interaction Effects ◽  
Rate Of Change ◽  
Latent Growth ◽  
Latent Growth Models ◽  
Highly Educated ◽  
Regression Techniques ◽  
Rate Of Decline

Background. Higher education has been posited to protect against cognitive decline, either because the rate of decline is slower in the more highly educated or the start of decline is delayed. Latent growth models provide improved methodology to examine this issue.Methods. The sample consisted of 887 participants aged 70–93 years in 1991 and followed up in 1994 and 1998. Latent growth models and standard regression techniques were used to examine the rate of cognitive decline in four cognitive measures while controlling for health status and sex. A delayed start model was examined by incorporating interaction effects in a regression model.Results. Neither the latent growth models nor the regression techniques revealed a slower rate of decline for the more highly educated. The proportion of the highly educated showing no change was no larger than the proportion of the less well educated. There were no significant age by education interaction effects, no chronologically later accelerations in the rate of change as a function of education, and no differences in rate of decline between the first measurement interval and the second.Conclusions. Education may not protect against cognitive decline although it is associated with long-term individual differences in level of functioning. The discrepancy between our study and others may be attributable to attrition effects, follow-up length, sample age, scaling artefacts and negative publication bias. Most importantly, practice effects may favour the better educated and hence account for the supposed protective effect in many longitudinal studies of cognitive change.

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