Upper Part Of Slope Research Articles

Winter Biology of the Siberian GrouseFalcipennis falcipennis

Abstract Density, movements, daily activity and behaviour of a wintering population of Siberian Grouse Falcipennis falcipennis was studied on radio-tagged birds in the Lower Amur region, 100 km North of Komsomol'sk (Khabarovsk region). For this species, the wintering period lasts 7–7.5 months — from October through April. Best wintering habitats occur in the middle and upper parts of slopes with tracts of mature spruce forests, dying stems and small openings surrounded by spruce-fir undergrowth. From January through March adult cocks occupy areas of 19.5± 13.9 ha, females 26.5± 17.3 ha; subadult cocks 128±70.5 ha, and subadult hens 151 ±22.9 ha. Although typically occurring in groups of 2–3 birds, by the end of winter, flock size increases to 4–6; winter aggregations averaged 3.06 birds, but up to 48% of encounters were with single individuals. Winter conditions do not interrupt numerous social contacts within the local population. The birds elaborate cryptic behaviour, its unwillingness to land on snow i...

Preventing landslides in times of rainfall: case study and FEM analyses

PurposeThe purpose of the paper is to present a new method of controlling through susceptible slopes in order to reduce the risk of landslides.Design/methodology/approachGeotechnical and geological characteristics were collected and different FEM analyses were carried out in a case study of the Alasht valley in Northern Iran in order to determine susceptibility to landslides and consider appropriate countermeasures. Gravel drain piles have a real feel of reducing the pore water pressure in times of seismic loading, so they are used as a remediation method. The results clearly show their effects and an increase in safety as a result.FindingsSince the water table situation has a significant effect on stability, the present study focused on an example of using a seepage controlling system and its effect on the safety factor for different slopes in the area of Alasht, Northern Iran. Several FEM analyses were carried out on a landslide susceptible case. The results from FEM analysis of different slopes in the study area show a high susceptibility to landslides for six sites. Installing a gravel drain pile surrounded by a non‐woven geotextile layer leads to an increase in the safety factor against landslides. As a result, after installing gravel drain piles in the upper parts of slopes in order to control run out and ground water rising up in times of heavy rainfall, the safety factor against landslides in both static and seismic loading improved significantly.Originality/valueThe literature regarding controlling seepage in order to reduce the risk of landslides is limited. This paper collects and analyses geotechnical and geological data from the Alasht valley as an example to show the high risk of susceptibility to landslides.

Seasonal and spatial changes of sand fly species in a canyon in the Carmel Mountains

Altogether, 4,008 sand flies belonging to seven species were collected over a period of one year in the micro-habitats of a single canyon in the Carmel Mountain ridge. The three most abundant were P. arabicus, P. tobbi, and P. simici. Our results suggest that none of the seven sand fly species was indifferent to the heterogeneity of the microenvironment inside the canyon. Apart from the rare P. perfiliewi, which was only collected on the upper part of the south-facing slope, and P. tobbi, which clustered on the north-facing slope, the bulk of the other sand flies were caught on the bottom of the canyon. During the summer, the catches of all sand fly species increased to reach their maximum number in August and September. In April and May, there was lush vegetation and humidity, so species were distributed evenly throughout their habitats. With the onset of summer dryness, the sand flies concentrated in the humid habitats. The rate of concentration was essentially higher for males than for females, and this variation may result from differences in the behavior of the two sexes. During our study, none of the 2,318 dissected female sand flies were positive for Leishmania promastigotes.

Analysis of earthquake-triggered failure mechanisms of slopes and sliding surfaces

Earthquake-induced landslides along the Dujiangyan-Yingxiu highway after the Ms 8.0 Wenchuan earthquake in 2008 were investigated. It was found that: (1) slopes were shattered and damaged during the earthquake and open tension cracks formed on the tops of the slopes; (2) the upper parts of slopes collapsed and slid, while the lower parts remained basically intact, indicating that the upper parts of slopes would be damaged more heavily than the lower parts during an earthquake. Large-scale shaking table model tests were conducted to study failure behavior of slopes under the Wenchuan seismic wave, which reproduced the process of deformation and failure of slopes. Tension cracks emerged at the top and upper part of model, while the bottom of the model remained intact, consistent with field investigations. Depth of the tension crack at the top of model is 32 cm, i.e., 3.2 m compared to the prototype natural slope with a height of 14 m when the length scale ratio (proto/model) is 10. Acceleration at the top of the slope was almost twice as large as that at the toe when the measured accelerations on shaking table are 4.85 m/s(2) and 6.49 m/s(2), which means that seismic force at the top of the slope is twice the magnitude of that at the toe. By use of the dynamic-strength-reduction method, numerical simulation was conducted to explore the process and mechanism of formation of the sliding surface, with other quantified information. The earthquake-induced failure surfaces commonly consist of tension cracks and shear zones. Within 5 m from the top of the slope, the dynamic sliding surface will be about 1 m shallower than the pseudo-static sliding surface in a horizontal direction when the peak ground acceleration (PGA) is 1 m/s(2); the dynamic sliding surface will be about 2 m deeper than the pseudo-static sliding surface in a horizontal direction when the PGA is 10 m/s(2), and the depths of the dynamic sliding surface and the pseudo-static sliding surface will be almost the same when the PGA is 2 m/s(2). Based on these findings, it is suggested that the key point of anti-seismic design, as well as for mitigation of post-earthquake, secondary mountain hazards, is to prevent tension cracks from forming in the upper part of the slope. Therefore, the depth of tension cracks in slope surfaces is the key to reinforcement of slopes. The depth of the sliding surface from the pseudo-static method can be a reference for slope reinforcement mitigation.

Habitat utilisation by the threatened Sichuan Partridge Arborophila rufipectus: consequences for managing newly protected areas in southern China

SummaryA number of former forest farms in southern Sichuan province, south-west China have been designated as protected areas following the 1998 logging ban in the upper Yangtze basin. These are within the range of the endemic Sichuan Partridge Arborophila rufipectus which has a fragmented distribution in the remnant broadleaf forests of this region, and is currently listed as ‘Endangered’ by IUCN. The design of a robust conservation plan for this species has been hampered by a lack of knowledge about its habitat preferences in a heavily modified environment. To remedy this, ranging behaviour and habitat utilization by this species was studied through a combination of a call count method and radio tracking of individual birds. The results indicate that A. rufipectus significantly prefers primary and older planted secondary broadleaf forest compared to forest degraded by human activity or scrub. Individual birds were found on the upper parts of slopes and made particular use of areas with a dense canopy and open understorey, whilst avoiding the lower slopes and areas close to trails where human disturbance is likely to be greater. The ongoing conservation programme for this partridge species is based on these findings and includes further protected area designations and management plans, the establishment of new forest corridors, and better control of hunting and other forms of forest exploitation.

Soil changes after forty years of succession in an abandoned coppice in the Czech Republic

Soil processes over forty years of woodland succession were studied in the abandoned coppices of the Děvín Nature Reserve, in the south-east of the Czech Republic. A total of 113 horizon samples from 34 profiles were taken in the 1960s and 2000s, following identical field and laboratory approaches, to characterize soil texture, contents of carbonates and organic matter, and soil reaction (pH/H2O, pH/KCl). Changes in the soil properties were discussed in relation to the gradual development of the mature woodland that replaced the former intensively managed ancient coppice. Four soil types (Luvisols, Regosols, Leptosols and Chernozems) and their horizons were statistically treated to identify distributions/shifts in the measured values from the past to the present. The following results were obtained: (1) The horizontal transport and sedimentation of sandy calcareous particles into the Leptosols topsoil led to increased acidity. (2) In Luvisols, the same was detected for fine clayey particles. This can be explained by the topographical occurrence of the two types — on the upper parts of slopes and under limestone cliffs for the former, and in the flat foothills for the latter soil type. (3) No acidification appeared except for Luvisols, whose luvic horizons E and Bt are, in contrast to the others, poor in calcium carbonate and relatively acidic. A decrease in acidity was recorded in KCl solution, but not in H2O. This is interpreted as the consequence of the buffering ability of the soil sorption complex. (4) Slightly improved humification was only detected in the surface horizons of Luvisols and Leptosols. (5) Contrary to expectations no illimerization, i.e. the migration of clay particles from topsoil to subsoil, was revealed.As forty years is apparently too short a time for significant vertical clay migration, it was concluded that i) horizontal migration and the accumulation of substrate particles was of at least the same importance asin situpedogenetic processes, and ii) soil property dynamics that could be linked with the changed woodland management were proved to act relatively slowly.

RΟCKFALL S DURING THE EARTHQUAKE OF 14/8/03 AND PROBABLE SOLUTIONS AT THE UPPER LEVEL OF DRIMONA S VILLAGE SLOPE, MUNICIPALITY OF SFAKIOTON LEUKADA ISLAND

Big rocky blocks of indicative dimensions of 2.5*2.5x2.5 m, were activated and fell down-slope during the earthquake (Ms=6.4) of 14/8/03 from the upper part of the hill slope behind Drimon village (Municipality of Sfakiotes in Leukada island). The area is geologically composed of thick bedded white neritic limestones, of Pantokratoras unit (Upper Triassic age). The slope angle is roughly 50° to the NW, at the place of rockfall activation. The limestone is cut in blocks of edge 2-3 m long, due to the geometry of the tectonic discontinuities and the orientation of bedding. In this paper, the mechanism of rockfalls was studied regarding to their horizontal and vertical jumps as well as their kinetic energy. Furthermore, the type, the geometry, the place of installation and the necessary absorbing capacity of barriers were studied for restraining future rockfalls in the area. According to our study, the blocks are necessary to be tied, in place, at the upper part of the slope, using bolting, wire cable and wire netting techniques. Nevertheless, two elastic metallic barriers, approximately 100 m long and 5 m high, able to absorb kinetic energy of 3000 kJ, were decided to be installed on the slope, for the case that blocks, of mean dimensions 2.5x2.5x2.5 m, fall down. These barriers will be placed at horizontal distances of 38.22 m and 94.08 m, from the rockfalls starting point.

Succession of secondary forests affected by pine wilt disease in western Japan followed on vegetation maps

Abstract. Succession, changes in the distribution pattern of forest vegetation, and Pinus forest survival following pine wilt disease were clarified based on phytosociological analysis and vegetation maps. Survival of Pinus forests was restricted to the early successional stages, which were located on ridges and the upper part of slopes. Subsequent to pine wilt disease, the succession progressed from early to late substages of Pinus forest, mixed deciduous and evergreen Quercus, to evergreen Quercus forest. Succession occurs in abandoned pine forests which apparently are in a bad state and are vulnerable to attacks by pine wilt disease.

Slope Evolution Processes of the Choja landslide, Southwest Japan

Landform and geological structure of a landslide slope are deformed from those of original slope by landslide movement. Slope evolution processes of the Choja landslide which have been active for more than five hundred years are examined geologically.Owing to the comparison of the present location of Serpentine in the sliding mass with the original one, the landslide slope was formed retrogressive landslides of three stages (Figs. 9, 13). The movement of the first stage was originated in the middle part of the present landslide slope. The second stage was originated from the boundary between middle and upper part of the slope along the present slip surface, and mass of two retrogressive landslides entered into the landslide slope from. the side slopes. The upper part of the landslide slope began to move in the third stage. Total displacement of the latter two stages are around 300m.The present landslide has correspondent movement to the retrogressive slope evolution, mentioned above. The velocity of surface displacement of the upper slope is larger than that of middle and lower slope. Wide and thin distribution of Serpentine layers in the sliding mass is thought to be formed by ductile deformation around the slip surface, which is shown in the displacement data by borehole inclinometers.

Trends in runoff and erosion processes over an arid limestone hillside, northern Negev, Israel / Tendances d'écoulement et des processus d'érosion sur une pente de colline aride calcaire, Negev du nord, Israel

Abstract The study describes an experimental site installed in an arid region for the study of spatial variations in rainfall, runoff and erosion processes along slopes. Data obtained indicate that despite the frequent development of universal overland flow, due to excess rainfall, runoff generated at the upper part of slopes, 60–70m in length, has little or no chance of reaching the slope base during most rainstorms and thus does not contribute to channel flow. The spatial distribution of areas contributing to channel storm flow was found to be similar to that observed in the humid regions. In both cases the contributing area is limited to a belt extending at the base of the slope area. An analysis of the factors affecting the spatial pattern of runoff development in the arid zone is presented. Suspended sediment data collected indicate that no correlation exists between observed sediment concentrations and runoff rates.

Die relikt-schwarzföhrenwälder des alpenostrandes

The Illyrian black pine occurring mainly in Yugoslavia has a disjunct area on the east side of the Alps in Austria. Within the “isolated sub-Illyrian colony” along the Thermenlinie (thermal spring line) south of Vienna, it prefers the altitude of the montane beech zone between 250 m–1250 m. Its ecological requirements with regard to soil dryness are met by dolomitized substrata, those for air humidity by a natural occurrence in the montane zone, on west-facing slopes in general, and on the upper parts of slopes; in this it shows a fundamental ecological difference from Quercus pubescens, which, though also Illyrian, requires dry air. In its distribution optimum along the east side of the Alps, the black pine forms closed wood communities (Seslerio-Pinetum and Chamaebuxo-Pinion), extending into the dealpine zone. In the (upper and lower) marginal zones of its occurrence it joins other communities, which phenomenon is facilitated by the fact that its top does not obstruct the passage of light. The major disjunctions of the Tertiary species are doubtless of preglacial origin, the minor disjunctions within the Illyrian subspecies may date from more recent (interglacial or postglacial) times.

The Soil Erosion on the Tea Garden in Shizuoka Prefecture

The soil erosion of the tea garden in Shizuoka Prefecture. was surveyed by enquete method.The obtained results were as follows;1. The ratio of the steep slope tea garden was increased since the World War II.2. The productivity of the steep slope tea garden was very low inspite of hard labor, similar with the other grain crops.3. The soil color of the steep slope tea garden was much reddish and a majority of the flat garden was blackish.4. The upper part of slope was eroded mainly in the typhoon season, but in the Ogasa mountain region also was eroded seriously in the rainy season.5. The mulching was customary available for preventing soil erosion of the tea garden and the terrace was also fitted considerably.