河南地区全新世环境考古研究进展及未来趋势

河南地区是中国文明起源的核心区域之一,史前文明璀璨发达,是开展全新世环境考古研究的理想区域。近二十年来,河南地区环境考古研究中,文化演化的环境背景分析成果突出,灾变事件影响及人类对环境变化的响应研究亦有涉及,数字环境考古工作也开始逐渐起步。但在河南地区仍缺少高分辨率古环境重建方面的研究,且已有环境考古研究多关注环境变化对文明演化的影响,而在人类活动对环境变化响应及其环境效应方面研究尚显不足。此外,随着RS、GIS等技术应用的不断深入以及对景观考古的不断关注,考古遗址预测模型以及史前人与自然关系的定量和模拟研究已成为当前国际环境考古研究的热点。     

Interactions between geomorphology and ecosystem processes in travertine streams: Implications for decommissioning a dam on Fossil Creek, Arizona

Travertine deposits of calcium carbonate can dominate channel geomorphology in streams where travertine deposition creates a distinct morphology characterized by travertine terraces, steep waterfalls, and large pools. Algae and microorganisms can facilitate travertine deposition, but how travertine affects material and energy flow in stream ecosystems is less well understood. Nearly a century of flow diversion for hydropower production has decimated the natural travertine formations in Fossil Creek, Arizona. The dam will be decommissioned in 2005. Returning carbonate-rich spring water to the natural stream channel should promote travertine deposition. How will the recovery of travertine affect the ecology of the creek? To address this question, we compared primary production, decomposition, and the abundance and diversity of invertebrates and fish in travertine and riffle/run reaches of Fossil Creek, Arizona. We found that travertine supports higher primary productivity, faster rates of leaf litter decomposition, and higher species richness of the native invertebrate assemblage. Observations from snorkeling in the stream indicate that fish density is also higher in the travertine reach. We postulate that restoring travertine to Fossil Creek will increase stream productivity, rates of litter processing, and energy flow up the food web. Higher aquatic productivity could fundamentally shift the nature of the stream from a sink to a source of energy for the surrounding terrestrial landscape.     

长江流域全新世环境考古研究进展

长江流域是我国重要的经济区和人类文明孕育、诞生和发展区,也是水旱等自然灾害频繁发生的地区,在该区开展全新世环境考古研究,对弄清全新世10.0~3.0 ka BP无文字记载期的环境演变和人地关系互动影响有着重要的科学意义。近年来,长江流域全新世环境考古主要以古洪水和海面变化事件地层学为依据和线索,从遗址时空分布学研究、典型遗址考古地层学研究,以及区域内自然沉积地层记录的环境演变背景特征研究这三个方面入手,在长江流域的上、中、下游地区均获得了有重要意义的进展,表明长江流域全新世环境考古正在向更深更广的领域发展。同时,国际环境考古研究也在不断深入发展,新出版的PAGES Magazine杂志就特别关注了分辨率高达一年至数月的过去沉积记录;遥感、GIS等技术和DNA等分子生物学技术正不断在环境考古领域得到应用。     

Impact of litter quality and soil nutrient availability on leaf decomposition rate in a semi-arid grassland of Northeast China

It was hypothesized that litter with higher N concentration would decompose faster than that with lower N concentration and that increased soil nutrient availability would stimulate litter decomposition. To examine the interspecific differences in decomposition rate of leaf litter in relation with differences in litter chemistry and soil nutrient availability, senescent leaves of four species Pennisetum flaccidum, Artemisia scoparia, Chenopodium acuminatum and Cannabis sativa, and soil samples with different fertilization treatments (no fertilization, N, P, and N + P fertilizations, respectively) were collected from a sandy grassland in Northeast China and incubated under laboratory conditions. The decomposition rate of leaf litter was determined by measuring the CO₂ emission during decomposition of litter. We found remarkable interspecific differences in leaf decomposition rates. Moreover, rates of litter decomposition at different incubation stages were correlated with different litter quality indices. The rate of litter decomposition was positively correlated with initial litter N concentration in the initial stage of the incubation, whereas it was negatively correlated with litter N and P concentrations in the late stage. Responses of litter decomposition to soil nutrient availability differed among species. Our results suggest that both indirect changes in litter quality through shifts of species composition/dominance and direct changes in soil nutrient availability under nutrient addition conditions could affect litter decomposition and consequently C and nutrient cycling of grassland ecosystems.     

中国行为地理学研究近期进展

在中国人文地理学人本主义转向的背景下,中国的行为地理学研究进入新一轮学习与借鉴西方行为地理学理论与方法的高潮,并力求构建具有中国特色的行为地理学研究框架,实施全方位的实证研究与规划应用.本文简要评述了西方行为地理学的最新进展,指出中国行为地理学发展需要借鉴多学科视角和先进技术手段,提升研究的学术价值与应用价值.2003...     

Sources of bias in weighted average inferences of environmental conditions

Weighted averaging is widely used for inferring environmental conditions from an observed species assemblage. However, weighted average inferences are known to be systematically biased, and linear corrections (i.e., deshrinking functions) are commonly applied to adjust for this bias. In this analysis, the magnitude of the biases in weighted average inferences (and therefore the values of the deshrinking coefficients) are shown to depend upon the range of conditions sampled in the calibration data set and the true optima and niche breadths of the species observed in the calibration data set. Since the range of conditions and the observed species can differ between the calibration data set and the new data set for which environmental conditions are inferred, the coefficients for the deshrinking function derived using the calibration data may not be applicable to inferences computed using a new data set. Thus, environmental inferences may still exhibit systematic errors even after application of the linear correction. The findings from the theoretical analysis are demonstrated using stream temperature and macroinvertebrate data collected from wadeable streams in the western United States.     

Talking whilst walking: a geographical archaeology of knowledge

This paper explores how understandings of the knowledge and lives of individuals can be gained through making geographical context more explicit within qualitative research methods. The paper will focus on 'conversations in place'. More particularly, it will suggest that conversations held whilst walking through a place have the potential to generate a collage of collaborative knowledge. Drawing on the work of Casey, the paper builds upon the notion of the 'constitutive co-ingredience' of place and human identity, and, through using documentary and empirical examples, will argue that 'talking whilst walking' can harness place as an active trigger to prompt knowledge recollection and production.     

The self-organization of step-pools in mountain streams

Spontaneous, autogenic self-organization has been described in numerous geomorphic systems, but it has not been investigated in detail with respect to coarse bedforms in general or step-pools in particular. In this paper, we review the spatial organization of step-pool systems and present example evidence of step-pool development as an autogenic self-organization process. We then outline the mathematical language for defining spatially divergent self-organization and test these ideas using two unique field examples from Oregon (Andrews Experimental Forest) and California (Baxter Creek), where step-pools developed from planar beds in artificially manipulated channels. Results show that step-pool development is consistent with a spatially divergent self-organization phenomenon. Entropy increases as initially undifferentiated planar channels diverge into steps and pools, then declines when a series of steps and pools of consistent size and spacing is established, signifying stability in the system. The self-organization process is accompanied by increasing flow resistance and decreasing slope (through increasing the “vertical sinuosity” of the step-pool profile and creation of low- or negative gradient pool areas), suggesting a minimization of stream power. The self-adjustment of the step-pool bed profile over time represents another manifestation of a general process that results in rhythmic patterns on the surface of Earth.     

从实时定位、环境监测到神经生理：行为地理学技术发展前沿

方法与技术的前沿性是行为地理学的学科特色,技术视角的学科梳理有助于认识行为地理的自身价值与优势。论文回顾了实时定位、环境监测与神经生理3项技术的发展脉络,围绕行为背景、行为环境、行为体验的技术应用进行了综述,并总结了空间—行为互动、地理背景不确定性、批判神经地理的理论推进与批判反思;进一步构建了融合动态背景—精细环境—实时体验的全面技术框架,形成了从背景到环境再到体验的行为地理综合研究体系,并提出了神经生理技术融入行为地理学研究的理论提升方向。论文旨在贡献地理流动性背景下的行为地理学创新路径,服务于行为地理学的知识生产与理论发展。     

Assessment of downstream trends in channel gradient, total and specific stream power: a GIS approach

Geographic Information Systems (GIS) analyses of Digital Elevation Models (DEMs) coupled with catchment area based discharge estimation techniques provide a relatively simple means of modelling contiguous downstream trends in channel gradient, total stream power, and in riverscapes conducive to regime analysis, also specific stream power. For a small, high relief, coastal catchment in SE Australia, good agreement was obtained between channel gradients derived from a 25 m cell-size DEM and field survey equivalents over distances of several kilometres, indicating that channel gradients derived from DEMs can have a reasonable degree of absolute as well as relative accuracy over multi-kilometre reach scales. Assessment of downstream rates of change in channel gradient and specific stream power across four river systems suggests that some of the river reaches most responsive to high magnitude floods occur in zones where these variables rapidly decrease downstream. Modelling of downstream trends in channel gradient, total and specific stream power from catchment-wide DEMs has potential to provide a framework with which to investigate conceptual and empirical models between channel gradient, stream power and the form and dynamics of river systems.     

Urban transformation of river landscapes in a global context

Over the past 50 years considerable progress has been made in understanding the impacts of urban development on river processes and forms. Such advances have occurred as urban population growth has accelerated around the world. Using a compilation of research results from more than 100 studies conducted in a range of areas (58 addressing morphological change), this paper describes how urbanization has transformed river landscapes across Earth’s surface, emphasizing the distribution of impacts in a global comparative context. Urban development induces an initial phase of sediment mobilization, characterized by increased sediment production (on the order of 2–10 times) and deposition within channels, followed by eventual decline that couples with erosion from increased runoff to enlarge channels. Data from humid and temperate environments around the world indicate that channels generally enlarge to 2–3 times and as much as 15 times the original size. Although research has emphasized temperate environments, recent studies of tropical areas indicate a tendency for channel reduction resulting from strong sediment erosion and deposition responses because of intense precipitation and highly weathered soils. Embryonic research in arid environments further suggests variable river responses to urbanization that are characterized by rapid morphological change over short distances. Regardless of location, the persistence of the sediment production phase varies from months to several years, whereas several decades are likely needed for enlarging channels to stabilize and potentially reach a new equilibrium. Urbanizing streams pose particular challenges for management given an inherent changing nature. Successful management requires a clear understanding of the temporal and spatial variations in adjustment processes.     

Transport and deposition of large woody debris in streams: a flume experiment

Large woody debris (LWD) is an integral component of forested streams of the Pacific Northwest and elsewhere, yet little is known about how far wood is transported and where it is deposited in streams. In this paper, we report the results of flume experiments that examine interactions among hydraulics, channel geometry, transport distance and deposition of floating wood. These experiments were carried out in a 1.22-m-wide×9.14-m-long gravel bed flume using wooden dowels of various sizes as surrogate logs. Channel planforms were either self-formed or created by hand, and ranged from meanders to alternate bars. Floating pieces tended to orient with long axes parallel to flow in the center of the channel. Pieces were deposited where channel depth was less than buoyant depth, typically at the head of mid-channel bars, in shallow zones where flow expanded, and on the outside of bends. We hypothesize that the distance logs travel may be a function of the channel's debris roughness, a dimensionless index incorporating ratios of piece length and diameter to channel width, depth and sinuosity. Travel distance decreased as the ratio of piece length to both channel width and radius of curvature increased, but the relative importance of these variables changed with channel planform. Large pieces can move further than our debris roughness models predict if greater than 50% of the active channel area is deeper than the buoyant depth of the piece, or if momentum is high enough to carry pieces across shallows. Our debris roughness model allows first-order prediction of the amount of wood transport under various channel geometries.     

Geometric adjustment of pools to changes in slope and discharge: a flume experiment

To characterize the factors controlling pool shape, 30 different forced pools were created utilizing a 50% triangular constriction in a 0.5-m wide, 6-m long recirculating flume. Pools were scoured from an initial plane bed of sand with a d₅₀ of 0.25 mm. Pool depth and length were measured and used as dependent variables in least-squares, multiple-regression analyses. Discharge, channel-bed gradient and energy slope were the independent variables. Additional linear-regression analyses were conducted with either pool depth or length and stream power. Results indicate that both pool depth and length are primarily a function of discharge. Channel-bed and energy slopes are also significantly related to pool length but are not significantly related to pool depth. Stream power is significantly related to both pool depth and length, but R² values for pool depth versus discharge indicate stronger relations than those between pool depth and stream power. Observations on the type of geometric adjustment indicate that pools may minimize their rate of energy expenditure primarily through elongation. In contrast, pool depth appears to be more sensitive to the characteristics of the constrictions that create the forced pools. The results suggest that many field studies may suffer from cross-correlation problems. In particular, channel erodibility may exert a more dominant influence on pool geometry than hydraulic controls in many constriction-influenced channels.     

The History of Archaeological Research in North East Greenland: Putting the GeoArk Project into Perspective

Geografisk Tidsskrift—Danish Journal of Geography 110(2):117–129, 2010

Starting with a brief presentation of the GeoArk Project and its goals, this paper focuses on the archaeological research history of North East Greenland, in particular the area of Sabine Ø and Clavering Ø, in order to view the current project in a wider context. The paper questions the myths about the ‘virgin’ land and it demonstrates how a number of expeditions, activities of professional hunters and trappers, and geopolitical matters in dispute between Denmark and Norway during the 1930s dramatically determined the quite ill fortune of the archaeological sites and monuments of the Thule culture in the study area.     

工业绿色化：工业环境地理学研究动向

工业绿色化是工业可持续发展的具体体现，是工业企业面对日益增强的政府、公众、市场等环境压力，为减少污染而做出行为决策的响应过程。西方国家企业对环境压力的响应已经从20世纪60年代抗拒回避的基本不合作转变到90年代的主动为之，并逐渐成为企业增强竞争力的主动行为。我国经济与环境的基本状况也赋予工业地理学家新的使命，即要积极参与到工业绿色化的研究中，探求环境压力与企业环保行为转变的内在关系，开展工业绿色化的评价、有效性等方面的研究，探索经济与环境双赢的途径。     

Families,jobs and mobility: a comparison of migration streams in Thailand and Colombia

An analysis of migration in developing countries is presented. The analysis concentrates on change at the individual level and the extent to which factors such as age, education, and length of residence can account for changes experienced by migrants in various migrant streams. The data concern Colombia and Thailand. The differences among migration streams between similar urban places, to large towns, and away from larger towns are considered.     

Elevated air temperatures in riparian ecosystems along ephemeral streams: The role of housing density

The semiarid southwestern United States is an area of rapid population growth. Urban development is encroaching upon many ecosystems, including riparian areas. Because most stream miles in the southwestern United States occur along ephemeral streams, recognizing how these ecosystems are affected by increasing urban land covers is imperative. In this study, we recorded air temperature at 30 cm above the ground surface within riparian ecosystems along nine ephemeral stream reaches in three levels of housing density: High Density (HD: >13 houses/hectare); Moderate Density (MD: 4–8 houses/hectare); Low Density (LD: <1 house/hectare) for two years in a rapidly growing city in southern Arizona. Annual and seasonal average diurnal 30-min air temperatures for each treatment show that HD air temperatures were consistently higher than LD and MD temperatures (∼0.5–1.5 °C) during the late-evening/early-morning and midday hours. Winter temperatures had the largest differences between HD and LD sites, as much as 1.4 °C. Because physiological activity in these riparian ecosystems is largely temperature-dependent, temperature shifts associated with increased housing density could result in major ecosystem changes in these semiarid areas.     

史前人类探索、适应和定居青藏高原的历程及其阶段性讨论

系统梳理了近年来的考古发现与研究成果,总结出人类向青藏高原扩散直至定居的5个阶段性发展过程：古老型智人自中更新世晚期就开始了对高原的适应;现代智人于40~30 ka前已经开启了对高原腹地的探索;末次冰消期以来的气候转暖时段,细石器人群向高原大范围扩散,并在全新世早中期的活动更为频繁;粟作农业人群至少在5.2 ka前进入高原东部低海拔的河谷地带,在4.8 ka以后开始定居在高原东部3 000 m以上海拔的区域;3.5 ka以来麦作的传入和牧业经济的发展助力人群大规模定居高海拔区域。人类在向高原扩散和定居的过程中经历了漫长的生理与文化适应,但受限于当前考古发现与研究材料,史前狩猎采集、农业和牧业等人群在高原的时空分布、对高海拔环境的生理与行为适应﹑与低海拔人群和以藏族为主的现代高原人群之间的联系,以及高寒地区河谷农业和山地高原面游牧双重经济活动对高寒文明形成的支撑作用和高寒文明的普适性等问题仍需要深入研究,期待未来多学科交叉融合共同推动对这些问题的理解。