scholarly journals Current condition of populations and spatial-environmental features of habitats of russet ground squirrel Spermophilus major

2021 ◽  
Vol 29 (1) ◽  
pp. 7-22
Author(s):  
Andrei R. Tukhbatullin ◽  
Oleg V. Brandler
Keyword(s):  
Ground Squirrel ◽  
Grazing Intensity ◽  
Cattle Grazing ◽  
Distribution Area ◽  
Low Density ◽  
Environmental Features ◽  
Meadow Communities ◽  
Grass Meadow ◽  
Main Factors ◽  
Suitable Habitats

The russet ground squirrel (Spermophilus major ) is known in the literature as a numerous widespread ground squirrel species. In recent decades, a decline in its abundance was found in some parts of its range. We have assessed the condition of this species in most parts of its distribution area based on our observations and interviews with local people. Spatial, landscape and vegetation cover parameters of S. major settlements have been studied. The research results showed a decline in the number, disappearance of settlements and a decrease in suitable habitats for this species. Small and medium-sized settlements with relatively low density of burrows, associated with low grass meadow communities typical for pastures and cattle grazing, prevail among the found settlements. One of the main factors for the decline in the number and disappearance of settlements of russet ground squirrel is, apparently, a decrease of pasture cattle grazing intensity. The continuing trend of degradation of pasture ecosystems may pose a threat to the existence of this species.

Grazing intensity of cattle on a complex of rangeland communities in Central Australia.

1980 ◽  
Vol 2 (1) ◽  
pp. 76 ◽  
Author(s):  
WA Low ◽  
WJ Muller ◽  
ML Dudzinski
Keyword(s):  
Perennial Grass ◽  
Grazing Intensity ◽  
Cattle Grazing ◽  
Annual Grass ◽  
Range Condition ◽  
Aerial Surveys ◽  
The Mean ◽  
Central Australia ◽  
Free Ranging

Distribution of cattle grazing the rangeland communities of Kunoth Paddock in central Australia was determined from aerial surveys at fortnightly intervals over a 4.5 year period. Mean density throughout the study was 3.5 cattle/km2 and varied between communities from 8.0 cattle/km2 to 0.4 cattle/km2 on the major communities and from 25.6 cattle/km2 to 3.2 cattle/km2 on the minor communities. Cow-days of use were calculated for seasonal intervals to show grazing intensity on the communities over ti~ne. Grazing concentrations throughout the study revealed three groups of utilization levels of the major communities. Foothill fans, Woodlands, Floodplains and Gilgaied plains received about twice the mean grazing intensity for the paddock. Mulga-annual grass received about average grazing intensity and Hills and Mulga-perennial grass received less than half the average grazing intensity. Our sti~dy shows that cattle graze range communities differentially in a free-ranging situation. This information is useful in interpreting results of range condition and trend studies, and also suggests that more uniform utilization of all the communities might be obtained by controlhng grazing distribution.

scholarly journals Factors affecting the distribution and abundance of the Endangered volcano rabbit Romerolagus diazi on the Iztaccihuatl volcano, Mexico

Oryx ◽  
2014 ◽  
Vol 49 (2) ◽  
pp. 366-375 ◽  
Author(s):  
Michael Hunter ◽  
Will Cresswell
Keyword(s):  
Habitat Type ◽  
Grazing Intensity ◽  
Cattle Grazing ◽  
Faecal Pellet ◽  
Conservation Priorities ◽  
Lower Altitude ◽  
Factors Affecting ◽  
Closed Forest ◽  
Pellet Counts ◽  
Strict Enforcement

AbstractThe volcano rabbit Romerolagus diazi is an Endangered species endemic to Mexico, with a range of < 400 km2. We investigated threats from destruction, fragmentation and degradation of habitat, hunting, and cattle grazing intensity in relation to the distribution and abundance of the volcano rabbit on the Iztaccihuatl volcano. Faecal pellet counts were taken as a proxy for rabbit abundance in 1,718 random 0.2 m2 quadrats at 859 sampling points along 25 transects, covering an area of c. 100 km2 at altitudes of 3,400–4,000 m. Presence of the species was significantly associated with absence of closed forest, absence of long grass types (not bunchgrass), shallow inclines, absence of cattle grazing, lower altitude, low hunting pressure (measured by proximity to ranger station), absence of bare ground and, contrary to previous findings, increased frequency of fire. The species was significantly more abundant in habitats with a greater percentage cover of zacaton (bunchgrass) and short grass types. It was significantly less abundant in areas with more hunting (measured by proximity to ranger station) and cattle grazing. Key conservation priorities are therefore the protection of the subalpine zacaton bunchgrass-dominated habitat type, strict enforcement of hunting laws and the removal of livestock from relevant national park boundary areas. However, the results suggest that frequent fires have a significant positive effect on the occurrence of the volcano rabbit as a result of habitat improvement and this is often a consequence of anthropogenic management of land for cattle grazing.

The Analysis of the Interface States of Low-Density Materials in the Forming Process

2012 ◽  
Vol 503-504 ◽  
pp. 696-699
Author(s):  
Qiao Li Wang ◽  
Yu Dong Zheng ◽  
Xin Liang ◽  
Ying Ling ◽  
Kun Qiao ◽  
...  
Keyword(s):  
Finite Element ◽  
Theoretical Analysis ◽  
Finite Element Simulation ◽  
Interface State ◽  
Interface States ◽  
Finite Element Models ◽  
Low Density ◽  
Forming Process ◽  
Element Simulation ◽  
Main Factors

The interface of two low-density materials is bent in the forming process, which decreases the performance of materials. The theoretical analysis of the interface state in the forming process was taken to solve this problem, and the results indicated that the viscosity of the low-density material was very important to the interface state. The finite element simulation was also used to investigate the factors that affect the interface state. The results revealed the viscosity of material and the pressure were the main factors that affected the interface state; the stress and displacement at the interface could be accurately predicted by the finite element models. The ultimate aim was to modify the relevant parameters in a way that could obtain the required interface states.

scholarly journals Potential Distribution of Blumea Balsamifera in China Using MaxEnt and The Ex-Situ Conservation Based on its Effective Components and Fresh Leaf Yield

2021 ◽  
Author(s):  
Lingliang Guan ◽  
YuXia Yang ◽  
Pan Jiang ◽  
Qiuyu Mou ◽  
Yunsha Gou ◽  
...  
Keyword(s):  
Climate Change ◽  
Ex Situ ◽  
Distribution Area ◽  
Future Climate Change ◽  
Climate Change Scenarios ◽  
Total Flavonoids ◽  
Fresh Leaf ◽  
Significant Difference ◽  
Leaf Yield ◽  
Suitable Habitats

Abstract Blumea balsamifera is a famous Chinese Minority Medicine, which has a long history in Miao, Li, Zhuang and other minority areas. In recent years, due to the influence of natural and human factors, the distribution area of B. balsamifera resources has a decreasing trend. Therefore, it is very important to analyze the suitability of B. balsamifera in China. Following three climate change scenarios (SSP1-2.6, SSP2-4.5 and SSP5-8.5) under 2050s and 2070s, geographic information technology (GIS) and maximum entropy model (MaxEnt) were used to simulate the ecological suitability of B. balsamifera. The contents of L-borneol and total flavonoids of B. balsamifera in different populations were determined by gas chromatography (GC) and ultraviolet spectrophotometry (UV). The results showed that the key environmental variables affecting the distribution of B. balsamifera were mean temperature of coldest quarter (6.18-26.57 ℃), precipitation of driest quarter (22.46-169.7 mm), annual precipitation (518.36-1845.29 mm) and temperature seasonality (291.31-878.87). Under current climate situation, the highly suitable habitat was mainly located western Guangxi, southern Yunnan, most of Hainan, southwestern Guizhou, southwestern Guangdong, southeastern Fujian and western Taiwan, with a total area of 24.1×104 km2. The areas of the moderately and poorly suitable habitats were 27.57×104 km2 and 42.43×104 km2, respectively. Under the future climate change scenarios, the areas of the highly, moderately, and poorly suitable habitats of B. balsamifera showed a significant increasing trend, the geometric center of the total suitable habitats of B. balsamifera would move to the northeast. In recent years, the planting area of B. balsamifera has been reduced on a large scale in Guizhou, and its ex situ protection is imperative. By comparison, the content of L-borneol, total flavonoids and fresh leaf yield had no significant difference between Guizhou and Hainan (P > 0.05), which indicated that Hainan one of the best choice for ex-situ protection of B. balsamifera.

Effects of local and landscape scale and cattle grazing intensity on Orthoptera assemblages of the Hungarian Great Plain

2007 ◽  
Vol 8 (3) ◽  
pp. 280-290 ◽  
Author(s):  
Péter Batáry ◽  
Kirill Márk Orci ◽  
András Báldi ◽  
David Kleijn ◽  
Tibor Kisbenedek ◽  
...  
Keyword(s):  
Grazing Intensity ◽  
Cattle Grazing ◽  
Landscape Scale ◽  
Great Plain

Mixed-grass prairie rhizome biomass is influenced by cattle grazing intensity

2012 ◽  
Vol 68 (1) ◽  
pp. 199-204 ◽  
Author(s):  
X. Dong ◽  
F.-C. Cheng ◽  
D. Wang ◽  
G. Wang ◽  
B. D. Patton ◽  
...  
Keyword(s):  
Grazing Intensity ◽  
Cattle Grazing ◽  
Mixed Grass Prairie ◽  
Mixed Grass ◽  
Rhizome Biomass

scholarly journals Impact of Past and Future Climate Change on the Potential Distribution of an Endangered Montane Shrub Lonicera oblata and Its Conservation Implications

Forests ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 125
Author(s):  
Yuan-Mi Wu ◽  
Xue-Li Shen ◽  
Ling Tong ◽  
Feng-Wei Lei ◽  
Xian-Yun Mu ◽  
...  
Keyword(s):  
Climate Change ◽  
Endangered Species ◽  
Potential Distribution ◽  
North China ◽  
Distribution Area ◽  
Future Climate Change ◽  
Interglacial Period ◽  
Last Interglacial ◽  
Conservation Implications ◽  
Suitable Habitats

Climate change is an important driver of biodiversity patterns and species distributions, understanding how organisms respond to climate change will shed light on the conservation of endangered species. In this study, we modeled the distributional dynamics of a critically endangered montane shrub Lonicera oblata in response to climate change under different periods by building a comprehensive habitat suitability model considering the effects of soil and vegetation conditions. Our results indicated that the current suitable habitats for L. oblata are located scarcely in North China. Historical modeling indicated that L. oblata achieved its maximum potential distribution in the last interglacial period which covered southwest China, while its distribution area decreased for almost 50% during the last glacial maximum. It further contracted during the middle Holocene to a distribution resembling the current pattern. Future modeling showed that the suitable habitats of L. oblata contracted dramatically, and populations were fragmentedly distributed in these areas. As a whole, the distribution of L. oblata showed significant migration northward in latitude but no altitudinal shift. Several mountains in North China may provide future stable climatic areas for L. oblata, particularly, the intersections between the Taihang and Yan mountains. Our study strongly suggested that the endangered montane shrub L. oblata are sensitive to climate change, and the results provide new insights into the conservation of it and other endangered species.

scholarly journals Response of Plant Fungal Diseases to Beef Cattle Grazing Intensity in Hulunber Grassland

Plant Disease ◽  
2020 ◽  
Vol 104 (11) ◽  
pp. 2905-2913
Author(s):  
Yawen Zhang ◽  
Zhibiao Nan ◽  
Xiaoping Xin
Keyword(s):  
Disease Incidence ◽  
Grazing Intensity ◽  
Cattle Grazing ◽  
Average Density ◽  
Plant Diseases ◽  
Large Herbivores ◽  
Adult Cattle ◽  
Disease Occurrence ◽  
Natural Grasslands ◽  
Vegetation Characteristics

The effects of grazing by large herbivores on biodiversity and ecosystem functioning have been extensively studied, whereas how grazing influence plant diseases, especially in natural grasslands, remains poorly understood. Therefore, we undertook a field study regarding a grazing trial in a temperate meadow steppe grassland to investigate mechanisms underlying grazing-host-pathogen interactions. The effects of cattle grazing at different grazing intensities of 0, 0.23, 0.34, 0.46, 0.69, and 0.92 AU/ha (where 1 AU= 500 kg of adult cattle) on the microenvironment, vegetation characteristics, and occurrence of diseases were evaluated. At the population level, the effects of grazing on grassland vegetation characteristics and disease varied with grassland plant species. Compared with nongrazing, grazing directly decreased the average density, coverage, and disease incidence of palatable and edible forages by 51.4, 62.4, and 82.4% in the 0.92 AU/ha treatment but increased the occurrence and prevalence of disease in remaining small herbs by 752.1%. At the community level, with the increase of grazing intensity, the pathogen load of the whole community in grassland was positively related to host coverage. In addition, there was a trend toward increased microtemperature and decreased microhumidity with increased grazing. Although occurrence of plant diseases in natural grasslands is influenced by a range of factors, comprehensive analysis highlighted the major role that cattle grazing intensity plays in the occurrence of plant diseases in natural grasslands. In addition to its direct effect, grazing also indirectly affects disease occurrence by shifting plant community structure and the microenvironment. However, direct effects of grazing intensity affected disease occurrence more than indirect effects.

scholarly journals Modelling the potential distribution and habitat suitability of the alien fungus Clathrus archeri in Romania

2021 ◽  
Vol 45 (2) ◽  
pp. 241-250
Author(s):  
Ciprian Bîrsan ◽  
Constantin Mardari ◽  
Ovidiu Copoţ ◽  
Cătălin Tănase
Keyword(s):  
Habitat Suitability ◽  
Potential Distribution ◽  
Rapid Expansion ◽  
Distribution Area ◽  
Maximum Entropy Model ◽  
Invasive Potential ◽  
Entropy Model ◽  
The Mean ◽  
Suitable Habitats ◽  
Model Approach

Clathrus archeri is a saprophytic fungus native to the southern hemisphere which was introduced in Europe in the early twentieth century. Although it is naturalized in most regions of Central Europe, in Romania it is considered rather a rare species because it has been identified in only a few localities. Because of the rapid expansion of its range throughout Europe some authors assign this species an invasive potential. The objective of the paper was to identify both the potential distribution area and the potential suitable habitats for expansion in Romania and to highlight the environmental variables driving the probability of its occurrence. The maximum entropy model approach implemented in Maxent was used to model the species? potential distribution. The results highlighted altitude, snow cover length, the mean temperature of the driest quarter, and precipitation in the coldest quarter as the most important predictors of species? potential distribution in Romania. The map of the predicted distribution showed that the highest probability of occurrence for this species is in the mountainous and adjacent areas, while the map of habitat suitability confirmed that the best environmental conditions are in the Carpathians, while the most unfavourable are in the south-eastern regions of the country.

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