Estimation of wind erosion rates by using Cs-137 tracing technique: A case study in Tariat-Xilin Gol transect, Mongolian Plateau

Wind erosion is one of the major environmental problems in semi-arid and arid regions. Here we established the Tariat-Xilin Gol transect from northwest to southeast across the Mongolian Plateau, and selected seven sampling sites along the transect. We then estimated the soil wind erosion rates by using the Cs-137 tracing technique and examined their spatial dynamics. Our results showed that the Cs-137 inventories of sampling sites ranged from 265.63 +/- 44.91 to 1279.54 +/- 166.53 Bq.m(-2), and the wind erosion rates varied from 64.58 to 419.63 t.km(-2).a(-1) accordingly. In the Mongolia section of the transect (from Tariat to Sainshand), the wind erosion rate increased gradually with vegetation type and climatic regimes; the wind erosion process was controlled by physical factors such as annual precipitation and vegetation coverage, etc., and the impact of human activities was negligible. While in the China section of the transect (Inner Mongolia), the wind erosion rates of Xilin Hot and Zhengxiangbai Banner were thrice as much as those of Bayannur of Mongolia, although these three sites were all dominated by typical steppe. Besides the physical factors, higher population density and livestock carrying level should be responsible for the higher wind erosion rates in these two regions of Inner Mongolia.

Using the RBFN model and GIS technique to assess wind erosion hazard of inner Mongolia, China

Soil wind erosion is the primary process and the main driving force for land desertification and sand-dust storms in and and semi-arid areas of Northern China. While many researchers have studied this issue, this study quantified the various indicators of soil wind erosion, using the GIS technology to extract the spatial data and to construct a RBFN (Radial Basis Function Network) model for Inner Mongolia. By calibrating sample data of the different levels of wind erosion hazard, the model parameters were established, and then the assessment of wind erosion hazard. Results show that in the southern parts of Inner Mongolia wind erosion hazards are very severe, counties in the middle regions of Inner Mongolia vary from moderate to severe, and in eastern are slight. Comparison of the results with other research shows conformity with actual conditions, proving the reasonability and applicability of the RBFN model. Copyright (C) 2007 John Wiley & Sons, Ltd.

Alteration mineral mapping using masking and Crosta technique for mineral exploration in mid-vegetated areas: a case study in Areletuobie, Xinjiang (China)

Thematic Mapper (TM) and Enhanced Thematic Mapper (ETM)+ data have been successfully employed in the field of mineral exploration to identify key minerals over arid and semi-arid terrains. However, redundant vegetation and cloud may seriously interfere with the discrimination of the minerals with diagnostic features. Therefore, in this study, we use masking technique to eliminate the negative influence of vegetation and cloud and Crosta technique to identify the diagnostic features of hydroxyl-minerals, carbonate-minerals and iron oxides. Then the anomalies were endowed with special colours and overlapped with the remote-sensing and geochemical data, overlaying images as remote-sensing anomalies. The mineral exploration work was carried through by synthetic analysis of the remote-sensing images, geochemical data and structures. Finally, areas with high correlation between the occurrence of hydrothermal alteration and presence of main faults and geochemical anomalies were considered as mineral exploration targets worthy of further detailed exploration programmes.

Altitudinal differences in the leaf fitness of juvenile and mature alpine spruce trees (Picea crassifolia)

In many plant species, leaf morphology varies with altitude, an effect that has been attributed to temperature. It remains uncertain whether such a trend applies equally to juvenile and mature trees across altitudinal gradients in semi-arid mountain regions. We examined altitude-related differences in a variety of needle characteristics of juvenile (2-m tall) and mature (5-m tall) alpine spruce (Picea crassifolia Kom.) trees growing at altitudes between 2501 and 3450 m in the Qilian Mountains of northwest China. We found that stable carbon isotope composition (delta C-13), area- and mass-based leaf nitrogen concentration (N-a, N-m), number of stomata per gram of nitrogen (St/N), number of stomata per unit leaf mass (St/LM), projected leaf area per 100 needles (LA) and leaf mass per unit area (LMA) varied nonlinearly with altitude for both juvenile and mature trees, with a relationship reversal point at about 3 100 m. Stomatal density (SD) of juvenile trees remained unchanged with altitude, whereas SD and stomatal number per unit length (SNL) of mature spruce initially increased with altitude, but subsequently decreased. Although several measured indices were generally found to be higher in mature trees than in juvenile trees, N-m, leaf carbon concentration (C.), leaf water concentration. (LWC), St/N, LA and St/LM showed inconsistent differences between trees of different ages along the altitudinal gradient. In both juvenile and mature trees, VC correlated significantly with LMA, N-m, N-a, SNL, St/LM and St/N. Stomatal density, LWC and LA were only significantly correlated with delta C-13 in mature trees. These findings suggest that there are distinct ecophysiological differences between the needles of juvenile and mature trees that determine their response to changes in altitude in semi-arid mountainous regions. Variations in the fitness of forests of different ages may have important implications for modeling forest responses to changes in environmental conditions, such as predicted future temperature increases in high attitude areas associated with climate change.

Seasonal and interannual variation in water vapor and energy exchange over a typical steppe in Inner Mongolia, China

In this study, we conducted eddy covariance (EC) measurements of water vapor exchange over a typical steppe in a semi-arid area of the Inner Mongolia Plateau, China. Measurement sites were located within a 25-year-old enclosure with a relatively low leaf area index (similar to 1. 5 m(2) m(-2)) and dominated by Leymus chinensis. Energy balance closure was (H + LE) = 17.09 + 0.69 x (Rn - G) (W/m(2); r(2) = 0.95, n = 6596). Precipitation during the two growing seasons of the study period was similar to the long-term average. The peak evapotranspiration in 2004 was 4 mm d(-1), and 3.5 mm d(-1) in 2003. The maximum latent heat flux was higher than the sensible heat flux, and the sensible heat flux dominated the energy budget at midday during the entire growing season in 2003; latent heat flux was the main consumption component for net radiation during the 2004 growing season. During periods of frozen soil in 2003 and 2004, the sensible heat flux was the primary consumption component for net radiation. The soil heat flux component was similar in 2003 and 2004. The decoupling coefficient (between 0.5 and 0.1) indicates that evapotranspiration was strongly controlled by saturation water vapor pressure deficit (VPD) in this grassland. The results of this research suggest that energy exchange and evapotranspiration were controlled by the phenology of the vegetation and soil water content. In addition, the amount and frequency of rainfall significantly affect energy exchange and evapotranspiration upon the Inner Mongolia plateau. (c) 2007 Published by Elsevier B.V.

Defoliation, nitrogen, and competition: effects on plant growth and resource allocation of Cleistogenes squarrosa and Artemisia frigida

Two species, Artemisia frigida Willd. (C-3, semishrub, and dominant on overgrazed sites) and Cleistogenes squarrosa (Trin.) Keng (C-4, perennial bunchgrass, and dominant or codominant on moderately grazed sites) were studied to determine the effects of defoliation, nitrogen (N) availability, competition, and their interactions on growth, biomass, and N allocation in a greenhouse experiment. The main treatments were: two nitrogen levels (NO = 0 mg N pot(-1), N1 = 60 mg N pot(-1)), two defoliation intensities (removing 60% of total aboveground biomass and no defoliation), and three competitive replacement series (monocultures of each species and mixtures at 0.5:0.5). Our results were inconsistent with our hypothesis on the adaptive mechanisms of A. frigida regarding the interactive effects of herbivory, N, and competition in determining its dominant position on overgrazed sites. Cleistogenes squarrosa will be replaced by A. frigida on over-grazed sites, although C. squarrosa had higher tolerance to defoliation than did A. frigida. Total biomass and N yield and N-15 recovery of C. squarrosa in mixed culture were consistently lower than in monocultures, whereas those of A. frigida grown in mixtures were consistently higher than in monocultures, suggesting higher competitive ability of A. frigida. Our results suggest that interspecific competitive ability may be of equal or greater importance than herbivory tolerance in determining herbivore-induced species replacement in semi-arid Inner Mongolian steppe. In addition, the dominance of A. frigida on overgrazed sites has been attributed to its ability to shift plant-plant interactions through (lap colonization, root niche differentiation, and higher resistance to water stress.

中国北方表沙无机碳储量及次生碳酸盐固碳潜力研究

This paper selected the Taklamakan Desert and the Badain Jaran Desert as the research areas, tested the carbonate content of surface-sand samples of dunes using Eijkelkamp carbonate goniophotometer, and analyzed the spatial-distribution characteristics of carbonate and estimated the carbonate-stock and secondary carbonate-stock in 1m depth of surface sand in the Taklamakan Desert and the Badain Jaran Desert. In addition, the paper test XRD, SEM, TDA, stable carbon isotope and radioactive strontium isotope of lacustrine deposits in the Taklamakan Desert and carbonates, such as kunkar, root canal, lacustrine deposits, sinter and calcrete, in the Badain Jaran Desert. Resting on the achievements by our predecessors, it analyzed the mineral-composition differences of the carbonates, calculated the contents of secondary carbonate and, furthermore, evaluated their potential of sequestration of CO2 in the atmosphere. The overall goal of this study was to increase our understanding of soil carbonate in the context of carbon sequestration in the arid region in China. That is, to advance our understanding about whether or not secondary carbonate in desert is a sink for atmospheric CO2. The following viewpoints were obtained: 1 Carbonate contents of surface-sand samples decend from the south to the north of the Taklamakan Desert. The minimum lies in the south and the maxmum in the mid. Carbonate content of surface-sand of megadunes in the Badain Jaran Desert has low value generally in the dune-crest and the base of slope, and large value in the mid. The average of Carbonate contents of all sorts of collected samples in the same area of the Taklamakan Desert has small diffetences. The average is about 9%. 2 Using carbonate contents as key parameters, calculate the carbon-stock of carbonates in 1m depth of surface sand in the Taklamakan Desert and the Badain Jaran Deser.They are 1.13Pg and 0.19 Pg respectively. There are 0.53Pg and 0.088Pg carbon-stock of secondary-carbonates in 1m depth of surface sand in the Taklamakan Desert and the Badain Jaran Desert. 3 Through testing data from XRD （X-ray diffraction）and TAD ( Thermal Analysis Data), the most significant conclusion derived from is that the main mineral ingredient is calcite in different carbonate substances in arid regions, From the SEM(Scanning electron microscopy ) images, can obtains the information about the micro environment of different carbonate forms in which they can grow. 4 Selected gas by termal cracking and traditional phosphoric acid method, their δ13C show that δ13C is a good parameter to indicate the micro environment in which different secondary carbonate forms. From the δ13C of the same type samples, if the redeposit degree is hard, theδ13C is light, the redeposit degree is weak, the δ13C is heave. and the δ13C of the different type samples, δ13C is mainly controlled by the micro environment in which secondary formed. if the procedure is characterized by redeposit and dissolve of marine facies carbonate, δ13C is heavy, it is characterized by CO2 which produced by plant respiration,δ13C is light. 5 From the δ13C of lacustrine deposit in the different grain size, there exsit certain differences in their micro environment and secondary degree among different grain size in the same grade. 6 The secondary carbonate content of lacustrine deposits in Taklimakan Desert is 47.26%. And those of root canal, sinter, calcrete, kunkar, lacustrine deposit and surface sand in Badain Jaran Desert are 91.74%, 78.46%, 76.26%, 87.87%, 85.37%and 46.49%, respectively. Of different grain size samples, the secondary carbonate contents of coarse fraction (20-63μm), sub-coarse fraction (5-20μm) and fine fraction (<5μm) are 80.10%, 47.2%and 50.07%, respectively. 7 There is no obvious relevance betweenδ13C of secondary carbonate and the content of secondary carbonate,theδ13C of secondary carbonate mainly reflects the parameters of secondary process, the content of secondary carbonate reflects difference of secondary degree.. 8 Silicates potentially supply 3.4 pencent calcium source during forming process of lacustrine deposits in Taklimakan Desert. If calcium source is mainly supplied by goundwater, it can be calculated that about 5.18 %, 6.13%, 5.68%, 5.64 % and 6.82% silicates supply calcium source respectively for root canal, kunkar, lacustrine deposit, calcrete and sinter, during the forming process of different kinds of carbonates in Badain Jaran Desert.

中国北方草本植物及表土有机质碳同位素组成

Recently, more and more attention has been paid to stable isotope ratios in terrestrial depositional systems. Among them, δ~(13)C value is mainly determined by the surface vegetation, while vegetation is directly related to climate, therefore, carbon isotope ratio in soil organic matter and pedogenic carbonate has been employed as an important paleoecological indicator. In order to test the paleoecological information extracted from stable isotope ratios in terrestrial depositional systems, it is necessary to study the relationships between δ~(13)C value in standing terrestrial plants and today climate, as well as between δ~(13)C value in modern surface soil organic matter and standing vegetation. Thus, these relationships were studied in this paper by means of analysing δ~(13)C in standing plants and modem surface soil organic matter in North China. The main results and conclusions are presented as following: 1. According to their δ~(13)C values, 40 C-4 species represent about 16% of the 257 plant species sarnpled from the North China. C-4 photosynthesis mainly occurs in Poaceae, Cyperaceae and Chenopidaceae families, and percentage representation of C-4 photosynthesis is up to 56% in Poaceae family. 2. The δ~(13)C values of C-3 plant species in North China vary from -21.7‰ to -32.0‰ with an average of -27.1‰, and 93% focus on the range of -24.0‰ ～ -30.0‰; δ~(13)C values of C-4 plant species in North China are between -10.0‰ ～ -15.5‰ with an average of -12.9‰, and 90% concentrate on the range of -11.0‰ ～ -15.0‰. 3. The δ~(13)C composition of C-3 plant species collected from Beijing, a semi-moist district, mainly vary between -27.0‰ ～ -30.0‰, and the average is -28.7‰; the δ ~(13)C values of plants in the semi-arid district, east and west to the Liu Pan Moutain, focus on the range of-26.0‰ ～ -29.0‰ and -25.0‰ ～ -28.0‰, respectively, with the mean value of -27.6‰ and -26.6‰, respectively; the δ~(13)C composition in the arid district dominantly vary from -24.0‰ to -29.0‰, with the average of -26.2‰, and among them, the δ~(13)C values of C-3 plant species in deserts are often between - 22‰ ～ -24‰; the δ~(13)C values in the cold mountain district concentrate on the range of -24.0‰ to -29.0‰, with the average of -26.3‰. 4. The main range of δ~(13)C composition of C-4 plant species, derived from Beijing, a semi-moist district, are -13.0‰ ～ -15.5‰; the semi-arid district, -11.0‰ ～ -14.0‰; the arid district, -11.0‰ ～ -14.0‰. The mean values of them are -14.0‰, -12.4‰,-12.7‰, respectively. 5. From east to west in North China, δ~(13)C values of C-3 plant species increase with longitude. The correlation between δ~(13)C ratios of C-3 plant species and longitude is linear. Changing temperate and precipitation and changing atmosphere pressure are spossible explanations. 6. Almost all C-3 plant species have the trends that their δ~(13)C values gradually increase with decreasing precipitation, decreasing temperature and increasing altitude. Our results show the increases of the δ~(13)C value by 0.30 ～ 0.45‰, 0.19 ～ 0.27‰ and 1.1 ～ 1.2‰ per 100 mm, I℃ and 1000 m, respectively, for all C-3 plant species together. 7. The δ~(13)C values of all C-3 plant species together and a part of C-3 species show highly significant linear correlation with the mean annual temperature, the mean annual precipitation and the altitude, and the results suggest that they can be used as proxies of these environmental variables, while, those without highly significant correlation, may be not suitable as the proxies. 8. The extent, which of responses of δ~(13)C composition to environmental variables, is different for each C-3 plant specie. 9. The δ~(13)C variations along altitude and longitude may be non-linear for C-4 p1ant species in North China. The mean annual temperature may be not important influential factor, thus, it suggests that the δ~(13)C composition of C-4 plant species may be not suitable as the proxy of the mean annual temperature. The influences of summer temperature on δ~(13)C values are much bigger than that of annual temperature, among them, the influence of September temperature is biggest. The mean annual precipitation may be one of the dominant influential factors, and it shows a highly significant non-linear relationship with δ~(13)C values, and the result indicates that δ~(13) C composition of C-4 plant species can be employed as the proxy of the mean annual precipitation. 10. The variations of δ~(13)C ratios do not show systematic trends along longitude, latitude and altitude for modern surface soil organic in Northwest China. ll. The δ~(13)C ratios of modern surface soil organic do not exhibit systematic patterns with temperature and precipitation in Northwest China, it suggests that, unless soil organic is transferred from pure C-3 or C-4 vegetation, the δ~(13)C composition of soil organic may be not used as proxies of climatic variables. 12. The δ~(13)C values of modem surface soil organic are heavier than that of standing vegetation, and the difference ofrnean δ~(13)C between them is -2.18‰. 13. Without considering the δ~(13)C difference between vegetation and soil organic, as well as the δ~(13)C drift in various enviromnent, we may not obtain the valuable information of C-3, C-4 relative biomass in vegetation. 14. The C-4 biomass contribution in vegetation increase with decreasing latitude, increasing longitude and decreasing altitude in Northwest China. The C-4 biomass almost are zero in those regions north to 38 ° N, or west to 100°E, or above 2400 m. 15. The C-4 relative biomass in vegetation increase with growing temperature and precipitation. and, C-4 plants are rare at those regions where the mean annual temperature is less 4 ℃, or the mean annual precipitation is less 200 mm, and their biomass contribution in vegetation are almost zero. Both the mean annual temperature and the mean annual average precipitation may be the important influential factors of C-4 distribution, but the dominant factors.

内蒙古草地植被群落生物量的梯度特征研究

Relationship between biology and environment is always the theme of ecology. Transect is becoming one of the important methods in studies on relationship between global change and terrestrial ecosystems, especially for analysis of its driving factors. Inner Mongolia Grassland is the most important in China Grassland Transect brought forward by Yu GR. In this study, changes in grassland community biomass along gradients of weather conditions in Inner Mongolia was researched by the method of transect. Methods of regression about biomass were also compared. The transect was set from Eerguna county to Alashan county (38° 07' 35" ~50° 12' 20" N, 101° 55' 25" -120° 20' 46" E) in Inner Mongolia, China. The sample sites were mainly chosen along the gradient of grassland type, meadow steppe-* typical steppe-*desert steppe-*steppification desert-^desert. The study was carried out when grassland community biomass got the peak in August or September, 2003 and 2004. And data of 49 sample sites was gotten, which included biomass, mean annual temperature, annual precipitation, accumulated temperature above zero, annual hours of sunshine and other statistical and descriptive data. The aboveground biomass was harvested, and the belowground biomass was obtained by coring (30 cm deep). Then all the biomass samples were dried within (80 + 5) °C in oven and weighted. The conclusion is as follows: 1) From the northeast to the southwest in Inner Mongolia, along the gradient of grassland type, meadow steppe-*typical steppe-*desert steppe-*steppification desert-* desert, the cover degree of vegetation community reduces. 2) By unitary regression analysis, biomass is negatively correlated with mean annual temperature, s^CTC accumulated temperature, ^10°C accumulated temperature and annual hours of sunshine, among which mean annual temperature is crucial, and positively with mean annual precipitation and mean annual relative humidity, and the correlation coefficient between biomass and mean annual relative humidity is higher. Altitude doesn't act on it evidently. Result of multiple regression analysis indicates that as the primary restrictive factor, precipitation affects biomass through complicated way on large scale, and its impaction is certainly important. Along the gradient of grassland type, total biomass reduces. The proportion of aboveground biomass to total biomass reduces and then increases after desert steppe. The trend of below ground biomass's proportion to total biomass is adverse to that of aboveground biomass. 3) Precipitation is not always the only driving factor along the transect for below-/aboveground biomass ratio of different vegetation type composed by different species, and distribution of temperature and precipitation is more important, which is much different among climatic regions, so that the trend of below-/aboveground biomass ratio along the grassland transect may change much through the circumscription of semiarid region and arid region. 4) Among reproductive allocation of aboveground biomass, only the proportion of stem in total biomass notably correlates to the given parameters. Stem/leaf biomass ratio decreases when longitude and latitude increase, caloric variables decrease, and variables about water increase from desert to meadow steppe. The change trends are good modeled by logarithm or binomial equations. 5) 0'-10 cm belowground biomass highly correlates to environmental parameters, whose proportion to total biomass changes most distinctly and increases along the gradient from the west to the east. The deeper belowground biomass responses to the environmental change on the adverse trend but not so sensitively as the surface layer. Because the change value of 0~10 cm belowground biomass is always more than that of below 10 cm along the gradient, the deference between them is balanced by aboveground biomass's change by the resource allocation equilibrium hypothesis.

亚洲地形和海陆分布变化对东亚环境格局形成演化的作用：数值模拟与地质记录对比

Earlier studies on the distribution of geological environmental indicators in China revealed drastic changes from a zonal climate pattern (planetary-wave-dominant pattern) in the Paleogene to a monsoon-dominant one in the Neogene, which suggested an inception of the initial East-Asian summer monsoon. However, there are different views about the time and causes of the changes.Here, we attempt to compile a series of paleoenvironmental maps based on newly collected climate indicators from the literatures and chronologically constrained evidence of geological maps in order to re-examine the temporal and spatial evolution of climate belts in China during the Cenozoic with special emphasis on the changes of the arid belt. These indicators include mammalian fauna, coal, carbonate concretions, jarosite, salt, gypsum deposits and pollen assemblages etc, with chronological controls that we believe reliable. Pollen assemblages and mammalian fauna have been classified into three categories (arid, semi-arid/sub-humid, humid) to reflect the intensity of aridity/humidity. Salt, jarosite and gypsum deposits are classified as the arid indicators. Carbonate concretions and coal are classified into the semi-arid/sub-humid and humid one respectively. Paleoenvironmental maps at 8 time slices have been reconstructed. They are the Paleocene, Eocene, Oligocene, Miocene, Early Miocene, Middle Miocene, Late Miocene and Pliocene.And furthermore, we attempt to use IAP^AGCM to simulate the evolution of climate belts in emphasizing on the changes of the rain band, and compare the results with the paleoenvironmental maps in order to examine the causes of the drastic paleoenvironmental changes near the Oligocene/Miocene boundary. 36 sensitive numerical experiments are carried out using the IAP__AGCM to analyze the impacts of the uplift of the Himalayan-Tibetan complex, shrinkage of the Paratethys Sea, expansion of the South China Sea and the development of the polar ice sheets on rain band in China.The main conclusions are as follows:The obtained results essentially confirm the earlier conclusions about a zonal climate pattern in the Paleogene and a different pattern in the Neogene, and illustrate that a monsoon-dominant environmental pattern with inland aridity formed by the Early Miocene, which is temporally consist with the onset of eolian deposits in China.Cenozoic cooling and the formation of polar ice sheets are unlikely the main causes to the changes of environmental patterns mentioned above in China. But northern hemispheric cooling and the ice-sheets can intensify the Siberian High Pressure, and strengthen the winter monsoon circulations and enhance the aridity in the west part of China. These results support the earlier studies.Shrinkage of the Paratethys Sea and uplift of the Himalayan-Tibetan complex played important roles in strengthening the East Asian monsoon and induceing the above changes of environmental pattern, which is consistent with the earlier studies. Furthermore, "the monsoon-dominant pattern" appears when the Himalayan-Tibetan complex reaches to about 1000-2000 meters high and the Paratethys Sea retreats to the Turan Plate.4) Expansion of the South China Sea is another significant factor that drives the evolution of environmental patterns. We believe that the above three factors co-act and drive the change of the environmental patterns from a planetary-wave-dominant one to a monsoon-dominant one. However, the impacts of each factor vary by regions. The uplift mainly increases the humidity in Southwestern China and the aridity in northwestern country. The shrinkage mainly increases the humidity in Northern China and also enhances the aridity in the northwestern country. The expansion greatly increases the humidity in the south part of China.

中国黄土的磁组构特征及其古风向指示意义

The transportation and deposition of eolian materials of Chinese loess is correlated and effected by the monsoon from the mid-high latitude. Therefore study of the winter monsoon evolution can help us to understand the dynamic mechanism to climate changes in the east-Asian areas. The anisotropy of magnetic susceptibility (AMS) measurements have been carried out on the samples from the last 250ka wind -blown loess-paleosol sequences at Baicaoyuan and Luochuan. And the main conclusions are following:The magnetic foliation is almost horizontal of the two sections. AMS canthus be represented by an oblate ellipsoid with average K3 perpendicular to thebedding plane and Ki within the bedding plane. It has also shown that the ^-factor isless than 0.5 of the majority of samples. So the two sections are normal magneticfabric for sediments.The degree of anisotropy always shows a strong correlation with the foliationrather than with lineation, therefore the anisotropy is controlled by the foliation.Furthermore the foliation is nearly less than 1.02 and shows the typical wind-blownsediments anisotropy.The intensity of winter monsoon, grain size of the eolian inputs, the foliationand the degree of anisotropy are somewhat inter-related. Generally, the higherintensity of the winter monsoon will carry coarser-grained eolian material, therebyresulting in a larger foliation during deposition. Also the post-depositional compactioncontributes to the anisotropy.The AMS features between loess and paleosol are somewhat different. Wefound that the F, P values of paleosol are lower than that of its parent loess respectively. Moreover, the difference does also exists between the two sections. The anisotropy of Baicaoyuan is more significant than Luochuan section, which maybe related with the location and the intensity of the post-deposition reworks.5. We note that the declination of the long axis is NWW in Baicaoyuan section and the observed NWW direction of the winter monsoon winds based on AMS is consistent with the view that the winter monsoons prevail along the NW-SE direction. But at the Luochuan section, because of the strong affection of the post-deposition reworks, the direction of the long axis is nearly random in the foliation and hardly recognizes the paleowind direction since the last two interglacials.Correlation between the two loess-paleosol sequences implies that it is available in arid or semi-arid areas to take AMS to recognize the paleowind directions on the Loess Plateau.

Relative growth of the limbs and trunk in sifakas: heterochronic, ecological, and functional considerations.

Limb, trunk, and body weight measurements were obtained for growth series of Milne-Edwards's diademed sifaka, Propithecus diadema edwardsi, and the golden-crowned sifaka, Propithecus tattersalli. Similar measures were obtained also for primarily adults of two subspecies of the western sifaka: Propithecus verreauxi coquereli, Coquerel's sifaka, and Propithecus verreauxi verreauxi, Verreaux's sifaka. Ontogenetic series for the larger-bodied P. d. edwardsi and the smaller-bodied P. tattersalli were compared to evaluate whether species-level differences in body proportions result from the differential extension of common patterns of relative growth. In bivariate plots, both subspecies of P. verreauxi were included to examine whether these taxa also lie along a growth trajectory common to all sifakas. Analyses of the data indicate that postcranial proportions for sifakas are ontogenetically scaled, much as demonstrated previously with cranial dimensions for all three species (Ravosa, 1992). As such, P. d. edwardsi apparently develops larger overall size primarily by growing at a faster rate, but not for a longer duration of time, than P. tattersalli and P. verreauxi; this is similar to results based on cranial data. A consideration of Malagasy lemur ecology suggests that regional differences in forage quality and resource availability have strongly influenced the evolutionary development of body-size variation in sifakas. On one hand, the rainforest environment of P. d. edwardsi imposes greater selective pressures for larger body size than the dry-forest environment of P. tattersalli and P. v. coquereli, or the semi-arid climate of P. v. verreauxi. On the other hand, as progressively smaller-bodied adult sifakas are located in the east, west, and northwest, this apparently supports suggestions that adult body size is set by dry-season constraints on food quality and distribution (i.e., smaller taxa are located in more seasonal habitats such as the west and northeast). Moreover, the fact that body-size differentiation occurs primarily via differences in growth rate is also due apparently to differences in resource seasonality (and juvenile mortality risk in turn) between the eastern rainforest and the more temperate northeast and west. Most scaling coefficients for both arm and leg growth range from slight negative allometry to slight positive allometry. Given the low intermembral index for sifakas, which is also an adaptation for propulsive hindlimb-dominated jumping, this suggests that differences in adult limb proportions are largely set prenatally rather than being achieved via higher rates of postnatal hindlimb growth.(ABSTRACT TRUNCATED AT 400 WORDS)

Validación de un modelo de balance hidrológico versátil para maíz en condiciones de semiáridez

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Impacts of wildlife on household food security and income in northeastern Tanzania

We evaluated the impacts of wildlife on household food security and income in three semi-arid villages adjacent to Lake Manyara National Park (LMNP) and Mkomazi Game Reserve (MGR) in Northeastern Tanzania. Survey data were collected using both household interviews and human-wildlife conflict related archive information from the village government offices. Crop destruction by wildlife influenced both household food security and cash income. Crop damage to households was, on average, 0.08 ton/annum, equivalent to two months household loss of food and reduced household cash income by 1.3%. A combination of measures is proposed as incentives for conservation. These include provision of economic incentives, soft loans to initiate non-farm (e.g., ecotourism, business enterprises) projects to ease dependency on natural resources, increasing of reserves buffer zones and fencing of reserves.

Attribution of Atmospheric Sulfur Dioxide over the English Channel to Dimethylsulfide and Changing Ship Emissions

Atmospheric sulfur dioxide (SO2) was measured continuously from the Penlee Point Atmospheric Observatory(PPAO) near Plymouth, United Kingdom between May 2014 and November 2015. This coastal site is exposed to marine air across a wide wind sector. The predominant southwesterly winds carry relatively clean background Atlantic air. In contrast, air from the southeast is heavily influenced by exhaust plumes from ships in the English Channel as well as near the Plymouth Sound. New International Maritime Organization (IMO) regulation came into force in January 2015 to reduce sulfur emissions tenfold in Sulfur Emission Control Areas such as the English Channel. Our observations suggest a three-fold reduction from 2014 to 2015 in ship-emitted SO2 from that direction. Apparent fuel sulfur content calculated from coincidental SO2 and carbon dioxide (CO2) peaks from local ship plum es show a high level of compliance to the IMO regulation (> 95 %) in both years. Dimethylsulfide (DMS) is an important source of atmospheric SO2 even in this semi-polluted region. The relative contribution of DMS oxidation to the SO2 burden over the English Channel increased from ~ 1/3 in 2014 to ~ 1/2 in 2015 due to the reduction in ship sulfur emissions. Our diel analysis suggests that SO2 is removed from the marine atmospheric boundary layer in about half a day, with dry deposition to the ocean accounting for a quarter of the total loss.