Aridity exacerbates grazing‐induced rangeland degradation: A population approach for dominant grasses

2020 ◽  
Vol 57 (10) ◽  
pp. 1999-2009
Author(s):  
Gastón R. Oñatibia ◽  
Gerónimo Amengual ◽  
Luciano Boyero ◽  
Martín R. Aguiar
Keyword(s):  
Population Approach ◽  
Rangeland Degradation ◽  
Dominant Grasses

Update on the Boundaries of the Curly Birch Range

2020 ◽  
pp. 9-21
Author(s):  
L.V. Vetchinnikova ◽  
◽  
A.F. Titov ◽  
◽  
Keyword(s):  
Population Size ◽  
Natural Populations ◽  
Forest Tree ◽  
Published Data ◽  
Population Approach ◽  
Key Factors ◽  
History Of ◽  
Individual Trees ◽  
Karelian Birch

The article reports on the application of the best known principles for mapping natural populations of curly (Karelian) birch Betula pendula Roth var. carelica (Mercklin) Hämet-Ahti – one of the most appealing representatives of the forest tree flora. Relying on the synthesis and analysis of the published data amassed over nearly 100 years and the data from own full-scale studies done in the past few decades almost throughout the area where curly birch has grown naturally, it is concluded that its range outlined in the middle of the 20th century and since then hardly revised is outdated. The key factors and reasons necessitating its revision are specified. Herewith it is suggested that the range is delineated using the population approach, and the key element will be the critical population size below which the population is no longer viable in the long term. This approach implies that the boundaries of the taxon range depend on the boundaries of local populations (rather than the locations of individual trees or small clumps of trees), the size of which should not be lower than the critical value, which is supposed to be around 100–500 trees for curly birch. A schematic map of the curly birch range delineated using this approach is provided. We specially address the problem of determining the minimum population size to secure genetic diversity maintenance. The advantages of the population approach to delineating the distribution range of curly birch with regard to its biological features are highlighted. The authors argue that it enables a more accurate delineation of the range; shows the natural evolutionary history of the taxon (although it is not yet officially recognized as a species) and its range; can be relatively easily updated (e.g. depending on the scope of reintroduction); should be taken into account when working on the strategy of conservation and other actions designed to maintain and regenerate this unique representative of the forest tree flora.

scholarly journals A Hybrid Multi-Population Approach to the Project Portfolio Selection and Scheduling Problem for Future Force Design

IEEE Access ◽  
2021 ◽  
pp. 1-1
Author(s):  
Kyle Robert Harrison ◽  
Saber Elsayed ◽  
Ivan L. Garanovich ◽  
Terence Weir ◽  
Michael Galister ◽  
...  
Keyword(s):  
Portfolio Selection ◽  
Project Portfolio ◽  
Scheduling Problem ◽  
Population Approach ◽  
Project Portfolio Selection

scholarly journals Assessment of Rangeland Degradation in New Mexico Using Time Series Segmentation and Residual Trend Analysis (TSS-RESTREND)

2021 ◽  
Vol 13 (9) ◽  
pp. 1618
Author(s):  
Melakeneh G. Gedefaw ◽  
Hatim M. E. Geli ◽  
Temesgen Alemayehu Abera
Keyword(s):  
Time Series ◽  
New Mexico ◽  
Trend Analysis ◽  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Rangeland Management ◽  
Environmental Benefits ◽  
Drought Severity ◽  
Assessment Framework ◽  
Rangeland Degradation

Rangelands provide significant socioeconomic and environmental benefits to humans. However, climate variability and anthropogenic drivers can negatively impact rangeland productivity. The main goal of this study was to investigate structural and productivity changes in rangeland ecosystems in New Mexico (NM), in the southwestern United States of America during the 1984–2015 period. This goal was achieved by applying the time series segmented residual trend analysis (TSS-RESTREND) method, using datasets of the normalized difference vegetation index (NDVI) from the Global Inventory Modeling and Mapping Studies and precipitation from Parameter elevation Regressions on Independent Slopes Model (PRISM), and developing an assessment framework. The results indicated that about 17.6% and 12.8% of NM experienced a decrease and an increase in productivity, respectively. More than half of the state (55.6%) had insignificant change productivity, 10.8% was classified as indeterminant, and 3.2% was considered as agriculture. A decrease in productivity was observed in 2.2%, 4.5%, and 1.7% of NM’s grassland, shrubland, and ever green forest land cover classes, respectively. Significant decrease in productivity was observed in the northeastern and southeastern quadrants of NM while significant increase was observed in northwestern, southwestern, and a small portion of the southeastern quadrants. The timing of detected breakpoints coincided with some of NM’s drought events as indicated by the self-calibrated Palmar Drought Severity Index as their number increased since 2000s following a similar increase in drought severity. Some breakpoints were concurrent with some fire events. The combination of these two types of disturbances can partly explain the emergence of breakpoints with degradation in productivity. Using the breakpoint assessment framework developed in this study, the observed degradation based on the TSS-RESTREND showed only 55% agreement with the Rangeland Productivity Monitoring Service (RPMS) data. There was an agreement between the TSS-RESTREND and RPMS on the occurrence of significant degradation in productivity over the grasslands and shrublands within the Arizona/NM Tablelands and in the Chihuahua Desert ecoregions, respectively. This assessment of NM’s vegetation productivity is critical to support the decision-making process for rangeland management; address challenges related to the sustainability of forage supply and livestock production; conserve the biodiversity of rangelands ecosystems; and increase their resilience. Future analysis should consider the effects of rising temperatures and drought on rangeland degradation and productivity.

P.1.c.023 Assessment of benzodiazepines-valproic acid pharmacokinetic interaction in adult epileptic patients: population approach

2010 ◽  
Vol 20 ◽  
pp. S247-S248
Author(s):  
K. Vucicevic ◽  
B. Miljkovic ◽  
M. Pokrajac ◽  
M. Prostran ◽  
Z. Martinovic ◽  
...  
Keyword(s):  
Valproic Acid ◽  
Pharmacokinetic Interaction ◽  
Population Approach ◽  
Epileptic Patients

HYPERTENSION – A PUBLIC HEALTH PROBLEM

2019 ◽  
Author(s):  
Adia Pilav ◽  
Emira Tanović-Mikulec ◽  
Suada Branković ◽  
Vedran Đido
Keyword(s):  
Public Health ◽  
High Risk ◽  
Public Health Problem ◽  
Integrated Approach ◽  
Community Level ◽  
Effective Control ◽  
Population Approach ◽  
Hypertension Control ◽  
Adequate Model ◽  
High Prevalence

Aim. The aim of this paper is to present public health importance of hypertension in population as one of the major CVD risk factor as well as a model of integrated approach to hypertension control at community level. Background. In spite of wide knowledge of pathophysiology and epidemiology in development of hypertension, ability to easily diagnose it, availability of efficient medications, hypertension continues to have high prevalence and setting up hypertension controls poses significant public health challenge. High prevalence of hypertension exists in all countries of the world, regardless of socioeconomic status of the country. It is estimated that the number of people with hypertension by 2025 will rise by 15-20%, and the number of sick people will increase up to 1.5 billion people worldwide. Methods. A review of the relevant literature which discusses the importance of defining clear strategies and interventions in the control of hypertension in countries, with particular emphasis on integrated hypertension management that has the greatest impact. Discussion. Effective and efficient hypertension control requires two approaches: population approach and individual approach to high-risk individuals. The balanced combination of population approach and an approach to access high-risk individuals is vital for the effective control of hypertension and cardiovascular diseases. Conclusions. Health systems in every country must be flexible and ready to provide adequate model of integrated approach to hypertension control at community level understanding their own local needs.

II. The Population Approach: Nutrition Recommendations for Healthy Children and Adolescents

PEDIATRICS ◽  
1992 ◽  
Vol 89 (3) ◽  
pp. 537-544
Keyword(s):  
Children And Adolescents ◽  
Growth And Development ◽  
Healthy Children ◽  
Population Approach ◽  
Dietary Recommendations ◽  
Total Fat

The primary goals of the dietary recommendations are to limit intakes of SFA to less than 10 percent of total calories, to provide sufficient calories for growth and development without promoting obesity, and to limit cholesterol to less than 300 mg/day. These may be achieved more easily if the intake of total fat is restricted to no more than 30 percent of calories.

SEASONAL VARIATIONS IN THE CHEMICAL COMPOSITION OF GRASSES HARVESTED FROM THE NATURAL PASTURE IN OGUN STATE SOUTH-WESTERN NIGERIA

2021 ◽  
Vol 20 (1) ◽  
pp. 65-77
Author(s):  
O. A. OKUKENU ◽  
B. T. AKINYEMI ◽  
P. A. DELE ◽  
A. A. OLAJIDE ◽  
A.O. JOLAOSHO ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Rainy Season ◽  
Crude Protein ◽  
P Value ◽  
Ogun State ◽  
Natural Pasture ◽  
Four Seasons ◽  
Acid Detergent Fibre ◽  
Different Seasons ◽  
Dominant Grasses

The research was carried was carried out to evaluate the chemical composition of the dominant grasses harvested from the natural pasture in selected villages in Ogun State, South-western Nigeria at different seasons. The study was carried out using a 4 × 6 factorial arrangement comprising four seasons (early rain, late rain, early dry and late dry) at six locations (Afami, Atokun, Ibooro, Ileniku, Ipaaya, and Okerori). Results showed that the crude protein (CP) content significantly (p<0.05) varied from 5.56 % for Okerori to 7.34 % for Ibooro and the grasses harvested at Afami had the highest (72.75 %) neutral detergent fibre (NDF) values with the least (68.75 %) value recorded for Okerori, while the acid detergent fibre (ADF) values ranged from 41.00 % for Atokun to 48.25 % for Okerori. Also, CP value as affected by the season ranged from 4.23 % for late rainy to 9.44 % for the early rainy season and NDF values from 67.33% for late dry to 72.33 % for late rainy season while the early dry season had the highest value (48.00 %) for ADF with the least value (40.33 %) was recorded for the early rainy season. The phosphorus (P) value was highest at Ipaaya (2.99 g/kg) with the least value observed at Okerori (1.62 g/kg). The value for calcium ranged from 2.55 g/kg at Afami to 6.59 g/kg at Okerori. The P value of grasses as affected by seasons ranged from 1.46 g/kg for early dry to 2.66 g/kg for early rainy seasons.

scholarly journals Towards evenly distributed grazing patterns: including social context in sheep management strategies

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e2152 ◽  
Author(s):  
Agustina di Virgilio ◽  
Juan Manuel Morales
Keyword(s):  
Social Context ◽  
Management Practices ◽  
Spatial Scales ◽  
Management Strategies ◽  
Domestic Sheep ◽  
Conservation Of Resources ◽  
Landscape Conservation ◽  
Sheep Grazing ◽  
Rangeland Degradation ◽  
Natural Grasslands

Background.A large proportion of natural grasslands around the world is exposed to overgrazing resulting in land degradation and biodiversity loss. Although there is an increasing effort in the promotion of sustainable livestock management, rangeland degradation still occurs because animals’ foraging behaviour is highly selective at different spatial scales. The assessment of the ecological mechanisms modulating the spatial distribution of grazing and how to control it has critical implications for long term conservation of resources and the sustainability of livestock production. Considering the relevance of social interactions on animals’ space use patterns, our aim was to explore the potential effects of including animals’ social context into management strategies using domestic sheep grazing in rangelands as case study.Methods.We used GPS data from 19 Merino sheep (approximately 10% of the flock) grazing on three different paddocks (with sizes from 80 to 1000 Ha) during a year, to estimate resource selection functions of sheep grazing in flocks of different levels of heterogeneity. We assessed the effects of sheep class (i.e., ewes, wethers, and hoggets), age, body condition and time since release on habitat selection patterns.Results.We found that social rank was reflected on sheep habitat use, where dominant individuals (i.e., reproductive females) used more intensively the most preferred areas and low-ranked (i.e., yearlings) used less preferred areas. Our results showed that when sheep grazed on more heterogeneous flocks, grazing patterns were more evenly distributed at all the paddocks considered in this study. On the other hand, when high-ranked individuals were removed from the flock, low-ranked sheep shifted their selection patterns by increasing the use of the most preferred areas and strongly avoided to use less preferred sites (i.e., a highly selective grazing behaviour).Discussion.Although homogenization and segregation of flocks by classes are common practices to increase flock productivity, we are proposing an alternative that employs behavioural interactions in heterogeneous flocks to generate more evenly distributed grazing patterns. This practice can be combined with other practices such as rotational grazing and guardian dogs (to decrease mortality levels that may be generated by sheep grazing on more risky habitats). This does not imply any modifications of livestock stocking rates and densities or any additional investments for labour and materials. Considering livestock behaviour is critical for the design of sustainable management practices that balance landscape conservation and livestock productivity.

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