Life cycle of Agapetus fuscipes (Trichoptera, Glossosomatidae) in a first-order upland stream in central Germany     

Georg Becker   《Limnologica》2005,35(1-2):52-60

The number of immature stages and the seasonal patterns of development are basic life history features of a stream dwelling species and knowledge about these important components are essential for understanding its adaptations to its dynamic environment. The life cycle of Agapetus fuscipes (Trichoptera, Glossosomatidae), one of the dominant scrapers in the upper and middle reaches of the Breitenbach, a first-order upland stream in central Germany, was analysed. The pronotum length and the relationship between pronotum length, larval biomass and case length showed seven distinct larval instars, contrary to earlier findings from the Breitenbach. In addition to a few trichopteran species from other functional feeding groups, A. fuscipes is the only scraping caddis fly reported to have more than five larval instars. The moult increments of pronotum length and larval biomass were distinctly lower than in glossosomatid species with five larval instars. A. fuscipes is clearly univoltine in the Breitenbach. First-instar larvae were found from July to the beginning of December, and second-instar larvae from July to January. At the beginning of December the population consisted of the instars I to V, and development did not cease during winter. The sixth-instar larvae occurred mostly in January, and the seventh-instar larvae were never present before January. The prepupae and pupae occurred in April. The last pupae were found at the beginning of September, although most of the emergence took place in June and July. At least five different immature stages with different ecological demands were present at any time throughout the year. The ecological advantage having two additional larval instars compared to other glossosomatid species may be to compensate for the high rate of mouthpart wear that occurs while the larvae feed on the rough Bunter Sandstone substratum. A further advantage may be to spread the risk of high mortality under unfavourable environmental conditions.  相似文献   

Photosynthesis-transpiration coupling model at canopy scale in terrestrial ecosystem   总被引：1，自引：0，他引：1  

REN Chuanyou  YU Guirui  WANG Qiufeng  Guan Dexin 《中国科学D辑(英文版)》2005,48(Z1)

At the hypothesis of big leaf, an ecosystem photosynthesis-transpiration coupling cycle model was established by the scaled SMPT-SB model from single leaf to canopy, and model parameterization methods were discussed. Through simulating the canopy light distribution, canopy internal conductance to CO2 can be scaled from single leaf to canopy by integrating to canopy using the relationship between single internal conductance and photosynthetic photon flux density. Using the data observed by eddy covariance method from the Changbai Mountains site of ChinaFLUX, the application of the model at the canopy scale was examined. Under no water stress, the simulated net ecosystem photosynthesis rate fitted with the observed data very well, the slope and R2 of the line regression equation of the observed and simulated values were 0.7977 and 0.8892, respectively (n = 752), and average absolute error was 3.78 μmol CO2 m-2s-1; the slope, R2 and average absolute error of transpiration rate were 0.7314, 0.4355 and 1.60mmol H2O m-2 s-1, respectively (n = 752). The relationship between canopy photosynthesis,transpiration and external environmental conditions was discussed by treating the canopy as a whole and neglecting the comprehensive feedback mechanism within canopy, and it was noted that the precipitation course affected the transpiration rate simulation badly. Compared to the models based on eco-physiological processes, the SMPT-SB model was simple and easy to be used. And it can be used as a basic carbon and water coupling model of soil-plant-atmosphere continuum.  相似文献   

Changes in the spatial scale of Beijing UHI and urban development   总被引：2，自引：1，他引：2  

YU Shuqiu  BIAN Lingen  LIN Xuechun 《中国科学D辑(英文版)》2005,48(Z2)

The seasonal and interannual variations of Beijing urban heat island (UHI) are investigated in this paper using the temperature data from 1960 to 2000 at 20 meteorological stations in the Beijing region, and then the relationship between the intensity and spatial scale of UHI and Beijing urbanization indices is analyzed and discussed. Main conclusions are the followings. First, Beijing UHI shows obvious seasonal variations, and it is strongest in winter, next in spring and autumn, and least in summer. The seasonal variation of the UHI mainly occurs in the urban area. The UHI intensity at the center of Beijing is more than 0.8℃ in winter, and only 0.5℃ in summer. Second, the intensity of Beijing HUI exhibits a clear interannual warming trend with its mean growth rate (MGR) being 0.3088℃/10 a. The MGR of HUI is largest in winter, next in spring and autumn, and least in summer, and the urban temperature increase makes a major contribution to the growth of HUI intensity. Third, since the Reform and Opening, the urbanization indices have grown several ten times or even one hundred times, the intensity of HUI has increased dramatically, and its spatial scale also expanded distinctively along with the expansion of urban architectural complexes. Fourth, the interannual variation of urbanization indices is very similar with that of HUI intensity, and their linear correlation coefficients are significant at a more than 0.001 confidence level.  相似文献   

A Possible Detection of the 26 December 2004 Great Sumatra-Andaman Islands Earthquake with Solution Products of the International GNSS Service   总被引：1，自引：0，他引：1  

J. Kouba 《Studia Geophysica et Geodaetica》2005,49(4):463-483

The main goal of this work is to critically review the IGS solution products and Precise Point Positioning (PPP) in order to demonstrate their potential to contribute to studies of large earthquakes such as the one that devastated Southeast Asia on December 26th, 2004. In view of a possible detection of the Mw 9.0 Sumatra-Andaman Islands Earthquake of December 26, 2004, position solutions, ranging from intervals of years to one second, of four International GNSS Service (IGS) stations within 3000 km of the epicenter were examined. The IGS combined, cumulative solution product (IGS04P51), consisting of epoch and station velocity solutions and based on data spans of several years prior to the earthquake, was used as a reference. Four IGS combined weekly position solutions (igs04P1301-4), two weeks before and after the earthquake, were utilized for the weekly solution resolution. PPP static and kinematic solutions with IGS Final combined orbits and clocks were used for the mean daily and instantaneous 5-min and 1-sec epoch solutions, respectively. The most significant changes, detected by both weekly and daily solutions occurred in longitude. The nearest IGS station ntus, about 1000 km east of the epicenter, moved westward about 15 mm, while the more distant Indian station iisc (∼ 2300 km NW from the epicenter), shifted about 15 mm eastward. In spite of position errors caused by interpolation of the 5-min IGS clocks, the 1-sec solutions, based on separate data sets, available only for two stations (iisc, dgar), still showed seismic surface waves, in particular at the Indian station iisc. Precise daily IGS combined polar motion and length-of-day products, after correcting for the atmospheric effects, also likely detected, statistically significant, anomalistic excitations on December 26, 2004 that could be caused by this great earthquake.  相似文献   

森林沼泽景观区中大比例尺化探找矿工作方法的研究--记大梁金矿的发现     

陈伟民  金浚  丁汝福 《矿产与地质》2005,19(6):665-668

大梁金矿是通过森林沼泽景观区开展1：50000和1：25000地球化学测量及综合地质工作而发现的,证明采用的森林沼泽景观中大比例尺化探方法是行之有效的.  相似文献   

Entropy Analysis of Multiple Scale Causality and Qualitative Causal Shifts in Spatial Systems*     

Jonathan D. Phillips 《The Professional geographer》2005,57(1):83-93

Spatial systems are typically characterized by multiple controlling factors and processes operating at different spatial and temporal scales (multiple scale causality [MSC]). An entropy decomposition‐based approach to MSC is presented here in two contexts. First, given maps or distributions of an observed phenomenon at two or more scales, the contribution at more local or global (relative to the primary scale of observation) controls to the observed entropy can be estimated. Second, a theoretical treatment of the entropy decomposition equations shows that as the range of scale is increased by broadening or narrowing resolutions or by incorporating more controls, the influence of larger or smaller‐scale influences not only changes, but may change qualitatively, e.g., in terms of having positive (entropy‐increasing) or negative (information‐increasing) effects. Such qualitative causal shifts have implications for efforts to use any single causal explanation across the molecular to planetary spatial and instantaneous to geological range of scales relevant to physical geography. The entropy decomposition method is illustrated with an application to soil landscapes in the Ouachita Mountains, Arkansas.  相似文献   

Mechanism of loading on plates due to explosive detonation     

W. L. Fourney  U. Leiste  R. Bonenberger  D. J. Goodings 《Fragblast: International Journal for Blasting and Fragmentation》2005,9(4):205-217

This paper investigates the various mechanisms and parameters that are responsible for delivering impulse to a vehicle that is unfortunate enough to detonate a buried mine. Small scale tests are used to examine the effects of air blast or ejected sand in imparting impulse to a plate that is located above the surface of the saturated soil that contains the explosive. Parameters such as confinement, stand off distance, depth of burial of the explosive, density of the soil, and saturation level of the soil are also examined.  相似文献   

甘肃春季(3～5月)沙尘暴成因分析   总被引：3，自引：7，他引：3  

郭慧  王式功  李栋梁  冯建英  陆登荣  张存杰 《中国沙漠》2005,25(3):412-416

甘肃春季(3～5月)沙尘暴小波变换分析清楚地反映了甘肃春季沙尘暴不同时间尺度周期振荡的交替作用。甘肃中西部自20世纪80年代以来变暖,其变暖与太阳黑子周期长度(SCL)密切相关。甘肃春季沙尘暴与甘肃中西部热力因子和降水研究表明,当冬季冷空气活动频繁,春季气温回升快,气温波动幅度大,降水偏少,甘肃春季容易发生沙尘暴。  相似文献   

Late Holocene environmental conditions in Coronation Gulf,southwestern Canadian Arctic Archipelago: evidence from dinoflagellate cysts,other non‐pollen palynomorphs,and pollen     

Anna J. Pieńkowski  Peta J. Mudie  John H. England  John N. Smith  Mark F. A. Furze 《第四纪科学杂志》2011,26(8):839-853

Boxcore 99LSSL‐001 (68.095° N, 114.186° W; 211 m water depth) from Coronation Gulf represents the first decadal‐scale marine palynology and late Holocene sediment record for the southwestern part of the Northwest Passage. The record was studied for organic‐walled microfossils (dinoflagellate cysts, non‐pollen palynomorphs), pollen, terrestrial spores, and sediment characteristics. ²¹⁰Pb, ¹³⁷Cs, and three accelerator mass spectrometry ¹⁴C dates constrain the chronology. Three prominent palaeoenvironmental zones were identified. During the interval AD 1470–1680 (Zone I), the climate was warmer and wetter than at present, and environmental conditions were more favourable to biological activity and northward boreal forest migration, with reduced sea‐ice and a longer open‐water (growing) season. The interval AD 1680–1940 (Zone II) records sea‐ice increase, and generally cool, polar conditions during the Little Ice Age. During AD 1940–2000 (Zone III), organic microfossils indicate an extended open‐water season and decreased sea‐ice, with suggested amelioration surpassing that of Zone I. Although more marine studies are needed to place this record into an appropriate context, the succession from ameliorated (Zone I) to cooler, sea‐ice influenced conditions (Zone II) and finally to 20th‐century warming (Zone III) corresponds well with several terrestrial climatic records from the neighbouring mainland and Victoria Island, and with lower‐resolution marine records to the west. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

Vegetation history of the penultimate glacial period (Marine isotope stage 6) at Ioannina,north‐west Greece     

K. H. Roucoux  P. C. Tzedakis  I. T. Lawson  V. Margari 《第四纪科学杂志》2011,26(6):616-626

The vegetational history of the penultimate glacial period, Marine Isotope Stage (MIS) 6 (c. 185–135 ka), has remained relatively unexplored. Here we present a new record from the Ioannina basin, north‐west Greece, which constitutes the highest‐resolution terrestrial pollen record for this interval produced to date. It shows that the vegetation history of MIS 6 in this region can be divided into two parts: an early period (185–155 ka) with pronounced oscillations in tree population extent, and a later period (155–135 ka) with much smaller tree populations and subdued oscillations. This pattern is analogous to the MIS 3/MIS 2 division during the last glacial in the same sequence, although the early part of MIS 6 had larger Pinus populations and fewer temperate trees relative to the equivalent interval in MIS 3. This implies cooler and wetter conditions, which is somewhat counterintuitive given the high summer insolation during MIS 6e, but is in line with other palaeoclimatic evidence from the Mediterranean. Comparison with North Atlantic records suggests that despite the absence of pronounced iceberg discharges during MIS 6, North Atlantic millennial‐scale variability had a significant downstream impact on tree populations in north‐west Greece. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献