scholarly journals Simulation of Vegetation Cover Based on the Theory of Ecohydrological Optimality in the Yongding River Watershed, China

Forests ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 1377
Author(s):  
Yixuan Zhang ◽  
Tingning Zhao ◽  
Changqing Shi ◽  
Qiang Ma
Keyword(s):  
Optimality Theory ◽  
Dynamic Equilibrium ◽  
Vegetation Coverage ◽  
Soil Conditions ◽  
River Watershed ◽  
Average Value ◽  
Growing Seasons ◽  
The Yongding River ◽  
Yongding River

During ecological restoration, it is necessary to comprehensively consider the state of vegetation in climate–soil–vegetation systems. The theory of ecohydrological optimality assumes that this state tends to reach long-term dynamic equilibrium between the available water supply of the system and the water demand of vegetation, which is driven by the maximization of productivity. This study aimed to understand the factors that affect the spatial distribution of vegetation and simulate the ideal vegetation coverage (M0) that a specific climate and soil can maintain under an equilibrium state. The ecohydrological optimality model was applied based on meteorological, soil, and vegetation data during the 2000–2018 growing seasons, and the sensitivity of the simulated results to input data under distinct vegetation and soil conditions was also considered in the Yongding River watershed, China. The results revealed that the average observed vegetation coverage (M) was affected by precipitation characteristic factors, followed by wind speed and relative humidity. The M, as a whole, exhibited horizontal zonal changes from a spatial perspective, with an average value of 0.502, whereas the average M0 was 0.475. The ecohydrological optimality theory ignores the drought resistance measures evolved by vegetation in high vegetation coverage areas and is applicable to simulate the long-term average vegetation coverage that minimizes water stress and maximizes productivity. The differences between M and M0 increased from the northwest to the southeast of this area, with a maximum value exceeding 0.3. Meteorological factors were the most sensitive factors of this model, and the M0 of the steppe was most sensitive to the stem fraction, mean storm depth, and air temperature. Whether soil factors are sensitive depends on soil texture. Overall, the study of the carrying capacity of vegetation in the natural environment contributes to providing new insights into vegetation restoration and the conservation of water resources.

scholarly journals Peculiarities and ecological consequences of climate warming in the Northern Caspian semi-desert

2021 ◽  
pp. 64-78
Author(s):  
M. K. Sapanov
Keyword(s):  
Climate Warming ◽  
Dynamic Equilibrium ◽  
Atmospheric Precipitation ◽  
Weather Conditions ◽  
Snow Accumulation ◽  
Formation Mechanisms ◽  
Average Value ◽  
Growing Seasons ◽  
Melt Water ◽  
Before And After

Data on the weather conditions and monitoring of vegetation ecosystems in the Northern Caspian semi-desert for the 70-year period were analyzed. A gradual increase in the average air temperature per hydrological year by 2.73ºC (0.039ºC/year) has been revealed. Before and after the 2000s its increase was caused by warming of the cold and warm period of the year, respectively. An increase of the annual atmospheric precipitation in the spring-summer period was detected, mainly in 1978–1995 due to April-June precipitation. The humidification coefficient dynamics allows distinguishing three periods. The first period (1951–1977) is characterized by insignificant fluctuations around the average value (0.30); the second period (1978–1994) is characterized by good moisture, and the third period (1995–2020), on the contrary, – by severe aridity. These climate changes have led to significant transformation of the snow cover formation mechanisms, the surface runoff of spring melt water, and the ground water level. Despite such fluctuations of natural conditions, the annual productivity of virgin vegetation remains in dynamic equilibrium, changing over time in a wave-like manner, with no introduction of heterogeneous species. The protective afforestation has no chance for sustainable development due to warming of the winter months by 2000, which led to the absence of additional moistening of forest crops for a long period due to the deficiency of snow accumulation and surface inflow of spring melt water. The shrinkage of forest stands was intensified by recurrent annual summer atmospheric droughts. The production of agricultural crops was discontinued since the mid-1990s due to their annual failure, as well as the aridity of the growing seasons. The climate warming of the last two decades has brought the landscape of the flat semi-desert territory of the Northern Caspian region ever closer to its original state without agricultural fields and forest plantations. The population of the region is forced to return to extensive cattle breeding, which has existed here since ancient times.

scholarly journals Vegetation Properties in Human-Impacted Riparian Zones Based on Unmanned Aerial Vehicle (UAV) Imagery: An Analysis of River Reaches in the Yongding River Basin

Forests ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 22
Author(s):  
Liangsuo Ren ◽  
Yadong Liu ◽  
Shurong Zhang ◽  
Lirong Cheng ◽  
Yujing Guo ◽  
...  
Keyword(s):  
River Basin ◽  
Life Forms ◽  
Vegetation Coverage ◽  
Riparian Zones ◽  
Plant Life Forms ◽  
Natural Factors ◽  
Plant Life ◽  
Aerial Vehicle ◽  
The Yongding River ◽  
Yongding River

Riparian zones, transitional areas between aquatic and terrestrial ecosystems, have high plant species diversities. However, they are extremely vulnerable to natural factors, such as changes in river hydrological conditions (floods, droughts) and disturbances from human activities (dams, farmland encroachment, etc.). The distribution of plant life forms and variations in the degree of vegetation coverage in a riparian zone can reflect changes in the environmental conditions. In this study, we analyzed eight reaches from the four main tributaries (Dongyang River, Yang River, Sanggan River, and Yongding River) of the Yongding River Basin, which were selected based on their climate, terrain, and degree of human disturbance. One reach was located on the Dongyang River (DYR), two reaches on the Yang River (YR1 and YR2), three on the Sanggan River (SGR1, 2, and 3), and two on the Yongding River (YDR1 and YDR2). Unmanned aerial vehicle (UAV) technology was used to obtain high-resolution, true-color, multispectral images. The distributions of the plant life forms and the differences in the vegetation coverage were analyzed in the eight selected riparian zones. The results showed that grasses dominated the riparian zone and shrubs and trees were sparsely distributed along both banks of all streams, excluding SGR2 and YDR1. The areas with an extremely high vegetation coverage classification accounted for the highest proportion in the DYR (29.3%), YR2 (48.1%), SGR1 (32.9%), SGR2 (39.9%), SGR3 (85.1%), YDR1 (36.7%), and YDR2 (51.1%) reaches. Extremely low vegetation coverage accounted for the highest proportion in the YR2 reach, reaching 37.4%. This study indicated that natural factors and human activities have a serious impact on the distribution of different plants life forms and vegetation coverage classifications in the riparian zones of the Yongding River Basin. We hope that this research can provide practical assistance in the efforts of ecological restoration and the management of riparian vegetation in the Yongding River Basin.

Monitoring of natural regeneration in a mixed deciduous forest

1999 ◽  
Vol 64 ◽  
Author(s):  
K. M. Tabari ◽  
N. Lust
Keyword(s):  
Survival Rate ◽  
Natural Regeneration ◽  
Deciduous Forest ◽  
Seedling Stage ◽  
Permanent Plots ◽  
Soil Conditions ◽  
Growing Seasons ◽  
Humus Layer ◽  
Beech Stand ◽  
Regeneration Phase

Monitoring  of natural regeneration in a dense semi-natural mixed hardwood forest on the  base    of ash, beech, oak and sycamore occurred over 3 years in the Aelmoeseneie  experimental    forest, Belgium. 40 permanent plots (4 m x 5 m) were selected in three  various humus types,    located in an ash stand and in an oak - beech stand. In all plots abundance  and top height of all    broad leaved regenerated species were determined at the end of the growing  seasons 1995 and    1998. In addition, the seedlings which appeared in the plots during 1996  and 1997 were    identified and followed up.    This study proves that in the investigated sites natural regeneration is  drastically poor and    diversity is low, in particular where the humus layer is more acidic (mull  moder) and the litter    layer is thick. No regeneration phase older than the seedling stage (h <  40 cm) is developed on    the different humus types. On average, total number of seedlings in 1995  amounts to 38    units/are in the ash stand and to 63 units/are in the oak - beech stand.  Survival rate over a 3-    year period is 37% and 42% respectively in the ash and oak - beech stands.  Total ingrowth    during the growing seasons 1996 and 1997 is virtually poor, indicating 16  and 8 units/are    respectively in above mentioned stands. Survival rate of occurring  seedlings, as well as the ingrowth of new seedlings are notably different (P < 0.05) according to the soil conditions of the    ash stand. Generally, the low presence of seedlings and the lack of  regeneration older than the    seedling stage reveal that the regeneration development encounters with a  critical problem. The    continuation of this process would likely result in a progressive  succession by the invasive and    the unwanted tree species.

Evaluation attempt of own body sensing amongst persons with and without scoliosis

2021 ◽  
pp. 1-6
Author(s):  
Elżbieta Szczygieł ◽  
Agata Gigoń ◽  
Izabela Cebula Chudyba ◽  
Golec Joanna ◽  
Golec Edward
Keyword(s):  
Idiopathic Scoliosis ◽  
Sensory Integration ◽  
Head Position ◽  
Clinical Test ◽  
Spine Deformity ◽  
Functional Tests ◽  
Body Proportion ◽  
Average Value ◽  
Age Range

BACKGROUND: Adolescent idiopathic scoliosis (AIS) is a common structural spine deformity affecting 2%–4% of adolescents. Due to the unknown cause of idiopathic scoliosis, its therapy is a long-term and often unsatisfactory process. In the literature, it is often suggested that problems related to the feeling of one’s own body are caused by AIS. OBJECTIVE: The aim of this study was to assess the feeling of one’s own body among children with and without scoliosis on the example of feeling the head position, pelvis shape and balance. METHOD: The research included 62 children: 30 with scoliosis and 25 without diagnosed scoliosis with an age range between 11 to 19 years. The minimum scoliosis value was 7∘ and the maximum was 53∘. The average value was 25∘. During the study, three functional tests were used: Cervical Joint Position Error Test (CJPET), Clinical Test of Sensory Integration on Balance (CTSIB) and Body proportion demonstration test (BPDT). RESULTS: The results of the tests showed statistically significant differences (CJPET p= 3.54* 10-14, CTSIB p= 0.0376, BPDT p= 0.0127). However, none of the studies showed a correlation between the results of people with scoliosis and the value of their Cobb angles.

scholarly journals Spatiotemporal Evolution Trajectory of Channel Morphology and Controlling Factors of Yongding River, Beijing, China

Water ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1489
Author(s):  
Hao Li ◽  
Xiaoming Xu ◽  
Minghao Wu ◽  
Zhicheng Liu
Keyword(s):  
Morphological Evolution ◽  
River Channel ◽  
Controlling Factors ◽  
Protection Measures ◽  
Temporal And Spatial ◽  
Restoration Strategies ◽  
Beijing China ◽  
The Yongding River ◽  
Yongding River ◽  
Evolution Trajectory

It is necessary to understand the evolution of a river channel when reconstructing its evolution process and analyzing the controlling factors essential for river management and ecological restoration. In the past 50 years, the ecological environment around the Yongding River has deteriorated considerably, and the downstream has been completely cut off. Despite this, few have studied its morphology. In this study, we analyze the morphology of the Yongding River (Beijing, China) stretching for 92 km in four different periods between 1964 and 2018. A data treatment is carried out based on GIS, and the morphological evolution trajectory of the river channel at the overall and reach scales is reconstructed. The results show that the river morphology has undergone significant changes: the channel width has narrowed by 31%, and the temporal and spatial patterns show significant differences. By analyzing the impacts of human activities and climate change in various periods, we find human intervention to be the most important controlling factor. Based on our results, we proposed a set of river restoration strategies and protection measures for the Yongding River to guide watershed management and land planning.

scholarly journals Using Long-Term Earth Observation Data to Reveal the Factors Contributing to the Early 2020 Desert Locust Upsurge and the Resulting Vegetation Loss

2021 ◽  
Vol 13 (4) ◽  
pp. 680
Author(s):  
Lei Wang ◽  
Wen Zhuo ◽  
Zhifang Pei ◽  
Xingyuan Tong ◽  
Wei Han ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Land Surface ◽  
Arabian Peninsula ◽  
Vegetation Coverage ◽  
Observation Data ◽  
Desert Locust ◽  
Meteorological Observations ◽  
Earth Observation Data ◽  
Vegetation Loss

Massive desert locust swarms have been threatening and devouring natural vegetation and agricultural crops in East Africa and West Asia since 2019, and the event developed into a rare and globally concerning locust upsurge in early 2020. The breeding, maturation, concentration and migration of locusts rely on appropriate environmental factors, mainly precipitation, temperature, vegetation coverage and land-surface soil moisture. Remotely sensed images and long-term meteorological observations across the desert locust invasion area were analyzed to explore the complex drivers, vegetation losses and growing trends during the locust upsurge in this study. The results revealed that (1) the intense precipitation events in the Arabian Peninsula during 2018 provided suitable soil moisture and lush vegetation, thus promoting locust breeding, multiplication and gregarization; (2) the regions affected by the heavy rainfall in 2019 shifted from the Arabian Peninsula to West Asia and Northeast Africa, thus driving the vast locust swarms migrating into those regions and causing enormous vegetation loss; (3) the soil moisture and NDVI anomalies corresponded well with the locust swarm movements; and (4) there was a low chance the eastwardly migrating locust swarms would fly into the Indochina Peninsula and Southwest China.

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