基于RS和GIS的四川省土地利用/覆盖变化及可持续利用研究

LUCC是全球变化研究的核心主题之一，也是社会经济可持续发展的关键问题。改革开放后四川的社会经济发展非常快，在各种因素的驱动下，土地利用/覆盖发生了深刻变化。目前四川省缺乏基于实际调查数据的、全域性的、具有连续时间序列的LUCC和驱动力分析及土地可持续利用研究成果，这对我们从全局上把握全省土地利用现状、发展变化趋势，利用土地政策参与宏观调控，实现长期可持续发展目标，建设资源节约型、环境友好型社会极为不利。本研究针对这一问题，选取全川八大土地利用类型作为研究对象，研究了全省1996年到2006年的土地利用/覆盖格局和变化情况，分析了不同尺度的驱动因素，对全省农用地和建设用地的集约利用状况、潜力进行了分析评价，并提出相应的对策措施。 1．1996年-2006年10年来整个省域的土地利用/覆盖格局变化。 （1）1996年-2006年全省的土地利用/覆盖格局 1996年，全省是一个以农用地为主的土地利用/覆盖格局，林地和牧草地属于优势覆盖类型（合占69.17%），居民点及工矿用地和交通用地合占只有3%左右。 2000年的LUCC格局较为明显的特点是耕地所占比重下降0.4个百分点，水域和未利用土地所占比重有所下降，牧草地保持不变，其余地类所占比重有所上升。 与2000年相比，2004年林草地的优势格局进一步得到强化（合占比重达到70.23%）。耕地面积占幅员面积的比重下降0.83个百分点，略有下降的有未利用土地、水域和牧草地。值得关注的是在“退耕还林还草”的大背景下，牧草地占幅员面积的比重下降0.04个百分点。 到2006年，仍为林草地为主导优势的格局，二者合占上升0.15%。在城市化快速推进的背景下，居民点及工矿用地中的城市用地和建制镇用地占比重超过15%，农村居民点占比重降至76%。交通用地中农村道路占比重降至57.8%,公路用地占比重升至37.5%。五个地貌区的土地利用/覆盖格局与全省的变化基本一致。值得关注的是盆西平原区的交通用地上升幅度和盆地丘陵区的未利用土地的开发利用力度明显大于其它地貌区。 （2）1996-2006年10年间土地利用/覆盖格局的变化 1996-2000年4年间，耕地、水域和未利用地三个地类下降，年均减少0.75、0.19和0.32个百分点。其中耕地年均减少49229.0公顷，约一半流向林地，13.77%流向园地，约20%流向建设用地。另外5个地类面积增长，增长绝对量最大的是林地，年均增长40063.7公顷，交通用地增幅最大，4年年均增长达1.95%。 2001-2004年是西部大开发逐步推进、“退耕还林还草”项目全面展开和土地整理深入实施的关键期，LUCC更为深刻。耕地、未利用地、水域和牧草地四个地类面积下降，其余地类按增长幅度依次是园地、交通用地、居民点及工矿用地和林地。耕地加速下降，年均降幅达到1.59%，其减少去向主要是林地（占66.75%）和园地（占19.84%），其增加来源主要是未利用地、园地和水域。交通用地的增幅最大，为3.96%,其增加主要来源于耕地、未利用土地和林地，分别占49.96%、16.63%和13.09%。居民点及工矿用地增长幅度为3.12%。 从1996年到2006年的10年间，耕地、未利用地、水域和牧草地下降幅度分别为10.36%、3.61%、1.34%和0.26%。园地增幅达23.61%。绝对面积增长最大的则是林地，达630733.3公顷。交通用地和居民点及工矿用地增幅也较大，分别为15.00%和9.31%。 10年间年均总变化量为310326.6公顷，2000年-2004年之间变化最大（为356865.8公顷），高于平均变化量，而1996-2000年间和2004-2006年间都小于平均变化量。 （3）10年间不同地貌区的LUCC变化 盆西平原区的特点是园地大幅上升达77%，居民点及工矿用地和交通用地也大幅上升，耕地、未利用地下降幅度大，该区耕地、水域、未利用地的减少强度和园地、居民点及工矿用地、交通用地的上升强度均居五区第一；盆地丘陵区的特点是牧草地下降幅度大，为-36.89%,交通用地、园地和林地上升幅度较大，该区耕地减少、未利用地减少、林地增加、居民点及工矿用地和交通用地增加的变化强度均居五区相应地类增减的第二位；盆周山地区的特点是耕地减少较多，交通用地和园地增长较大，该区林地变化强度居各区第一位，牧草地和水域变化强度居各区第二位，耕地、居民点及工矿用地和未利用地居各区第三位；川西南山地区的特点是园地、耕地、交通用地和居民点及工矿用地变化幅度大，另外四个地类变化较小。该区减少的牧草地占全省牧草地减少的97.91%，变化强度居各个地貌区的第一位，园地相对变化强度居五区的第二位；川西北高山高原区的特点是耕地大幅下降、园地大幅上升，交通用地升幅也较大，其余地类变化不大。值得注意的是，该区牧草地和水域面积增加，与全省该地类的变化相反。其余地类的相对变化强度均是五个地貌区中最小的。 用变化强度分值考量变化强度，盆西平原区的变化强度最大，盆地丘陵区和盆周山地区的变化强度相当，川西北高山高原区的变化强度则要小得多。 （4）1996年及2006年全省土地利用/覆盖格局的景观生态学分析 全省是以自然景观占优势（占约70%）、农业景观为补充、建设用地景观居于从属地位的土地利用景观格局。景观多样性和均匀度不高。到2006年，全省总的景观格局并无大的改变。总体情况是随着时间的推移和人类活动的加强，区内景观优势度上升、多样性和均匀度变小。但斑块数减少，斑块面积和斑块孔隙度有所增大。斑块的形状指数和分维数均有所下降，表明受人为干扰有加剧的趋势。反映景观格局结构的破碎度指数有轻微下降。景观指数的变化表明全省土地利用有缓慢集中、规模聚集的趋势。 （5）三大生态建设工程对土地利用/覆盖变化的影响 1996-2006年间LUCC与三大生态建设工程实施的耦合分析，发现退耕工程对耕地、林地、牧草地等地类覆盖变化的影响最大，天保工程次之，长防工程最小。 2.四川省LUCC驱动力分析 （1）总体分析： 从整体上分析，人为因素对区域整体LUCC的影响从1996年的63.32%增加到2006年的66.99%，变得日益强烈。同时人为因素影响强度表现出明显的区域差异，地势平缓、经济区位条件好的区域其人为影响强度明显较高。 政策体制转变下的经济高速增长、快速的城市化、工业化过程和生态建设是四川省LUCC宏观尺度的驱动因素。区域的LUCC主要受到了由内向外(从城市到乡村)和由外向内(从山顶向平地)两种作用力的共同推动。局部尺度上，如距离交通线、水利线、中心城市的远近，地形凸起、大型独立项目落址、重污染项目的阻隔等，甚至一些乡规民俗等因素也会成为LUCC的驱动影响因素。在较小的尺度上,人类个体行为选择对LUCC的影响也是存在的。 　　根据驱动因子的特性作者将其划分为驱变、阻变、良性、惰性因子等类型。 （2）分地貌区的驱动因子分析 各地貌区都存在城市化、工业化、生态工程实施、自然灾害等驱动因子，但主次不一。对于盆西平原和盆地丘陵区，城市化、工业化是前两位的因子，而对另外三个地貌区，生态工程实施和产业结构调整则成为第第一、二位的驱动因子。 （3）分地类的驱动因子分析（以坡耕地为例） 分坡度的耕地变化分析发现，耕地减少主要集中在2°以下的平地、15°-25°和25°以上三个坡度级，是其它坡度级耕地减幅的三倍左右。这表明耕地减少受城市化进程和“退耕还林还草”工程驱动影响尤为巨大。 3.土地利用格局优化、集约利用评价和可持续利用及对策研究 （1）土地利用格局优化的战略选择及调整预测 土地利用格局调整的战略是农业生产用地、建设用地和生态及其他用地占幅员的比重分别稳定在13%、7%和80%左右，重点是三大类别内部二级和三级地类的合理调整。 （2）全省土地集约利用评价 全省农用地利用集约度为0.46，总体上集约度不高，处于较适度利用阶段。建设用地利用集约度为0.38，处于较适度利用阶段。集约利用提升空间较大。 农用地的潜力主要在于加强土地保育、完善利用制度、提高单产。城市建设用地的包括存量潜力、强度潜力、结构潜力，空间很大。农村居民点整理潜力可以逐步挖掘。 （3）新增建设用地集约利用的统筹安排 据测算，到2020年，四川省城市建设用地需求量在463850-492360hm2之间，城镇各业新增建设用地规模为361276.79hm2，占用耕地200565.94 hm2。2004-2020年间四川省农村居民点整理潜力33.86万hm2。农村居民点建设用地需求量为70.57万公顷。 （4）土地集约利用措施与坡耕地可持续利用战略 提出了土地集约利用的措施。在对坡耕地生态系统结构与功能分析的基础上，提出坡耕地可持续利用战略与生态恢复战略，并从技术和政策层面提出了坡耕地合理利用和生态退耕的措施和建议。 LUCC is one of the key questions of global change and sustainable development of society. After the opening and reform of China, the society and economy of Sichuan Province developed very fast ,the land-use/cover changed very strong droved by many factors .But nowadays we have no constant spatial-temporal study and driving force analysis about the whole province based on investigation. And it is lack of land sustainable utilization study based on correlative study. So we choose all the land resource in Sichuan, combine RS and GIS and field investigation, and take statistic-mathematic means and system analysis, to study the LUCC patterns and different scale driving force of different physiognomy regions, land cover types and periods; to analyze the current situation and potential of land resource intensive utilization, and gave out corresponding measurements. We found that forest and grassland are the dominant cover types of Sichuan provincial land –use/cover pattern, and becoming more and more stronger from 1996 to 2006,the natural landscape is the metric and occupy 70%,the diversity and evenness index are not high; the totally change quantity from 2000 to 2004 is the biggest; cultivated land especially steep cultivated land ,garden plot, forestry land ,settlement and industry land and traffic land changed relative stronger; among five physiognomy regions ,the changing intensity of PEN XI PING YUAN QU is the biggest, CHUAN XI BEI GAO SHAN GAO QU is smallest; under the background of policy system changing, the fast developing of economy, fast urbanization and industrialization and ecology construction are the macro-scale driving force of Sichuan provincial LUCC; to compare the impacts of “TUI GENG GONG CHENG” on LUCC especially to cultivated land ,forestry land and grassland is strongest, “TIAN BAO GONG CHENG ” is stronger,“ HANG FANG GONG CHENG” is smallest; the intensive utilization level of farmland and construction land of whole province is relative moderation, there is huge potential to excavate and fulfill the increasing demand of construction land；we must take synthetic measurements to accelerate the sustainable utilization of land resource, including administrative, economical ,technological and ecological policies.

a new client-to-client password-authenticated key agreement protocol

Natl Univ Defen Technol, China & Nanyang Technol Univ, NUDT

Spatial patterns and driving forces of land use change in China during the early 21st century

Land use and land cover change as the core of coupled human-environment systems has become a potential field of land change science (LCS) in the study of global environmental change. Based on remotely sensed data of land use change with a spatial resolution of 1 km x 1 km on national scale among every 5 years, this paper designed a new dynamic regionalization according to the comprehensive characteristics of land use change including regional differentiation, physical, economic, and macro-policy factors as well. Spatial pattern of land use change and its driving forces were investigated in China in the early 21st century. To sum up, land use change pattern of this period was characterized by rapid changes in the whole country. Over the agricultural zones, e.g., Huang-Huai-Hai Plain, the southeast coastal areas and Sichuan Basin, a great proportion of fine arable land were engrossed owing to considerable expansion of the built-up and residential areas, resulting in decrease of paddy land area in southern China. The development of oasis agriculture in Northwest China and the reclamation in Northeast China led to a slight increase in arable land area in northern China. Due to the "Grain for Green" policy, forest area was significantly increased in the middle and western developing regions, where the vegetation coverage was substantially enlarged, likewise. This paper argued the main driving forces as the implementation of the strategy on land use and regional development, such as policies of "Western Development", "Revitalization of Northeast", coupled with rapidly economic development during this period.

Study on spatial pattern of land-use change in China during 1995-2000

It is more and more acknowledged that land-use/cover dynamic change has become a key subject urgently to be dealt with in the study of global environmental change. Supported by the Landsat TM digital images, spatial patterns and temporal variation of land-use change during 1995 -2000 are studied in the paper. According to the land-use dynamic degree model, supported by the 1km GRID data of land-use change and the comprehensive characters of physical, economic and social features, a dynamic regionalization of land-use change is designed to disclose the spatial pattern of land-use change processes. Generally speaking, in the traditional agricultural zones, e.g., Huang-Huai-Hai Plains, Yangtze River Delta and Sichuan Basin, the built-up and residential areas occupy a great proportion of arable land, and in the interlock area of farming and pasturing of northern China and the oases agricultural zones, the reclamation I of arable land is conspicuously driven by changes of production conditions, economic benefits and climatic conditions. The implementation of "returning arable land into woodland or grassland" policies has won initial success in some areas, but it is too early to say that the trend of deforestation has been effectively reversed across China. In this paper, the division of dynamic regionalization of land-use change is designed, for the sake of revealing the temporal and spatial features of land-use change and laying the foundation for the study of regional scale land-use changes. Moreover, an integrated study, including studies of spatial pattern and temporal process of land-use change, is carried out in this paper, which is an interesting try on the comparative studies of spatial pattern on change process and the change process of spatial pattern of land-use change.

Tight intermolecular packing through supramolecular interactions in crystals of cyano substituted oligo(para-phenylene vinylene): a key factor for aggregation-induced emission

Strong supramolecular interactions, which induced tight packing and rigid molecules in crystals of cyano substituent oligo(para-phenylene vinylene) (CN-DPDSB), are the key factor for the high luminescence efficiency of its crystals; opposite to its isolated molecules in solution which have very low luminescence efficiency.

A key gene of the RNA interference pathway in the black tiger shrimp, Penaeus monodon: Identification and functional characterisation of Dicer-1

RNA interference (RNAi) is an evolutionarily conserved mechanism by which double-stranded RNA (dsRNA) initiates post-transcriptional silencing of homologous genes. Here we report the amplification and characterisation of a full length cDNA from black tiger shrimp (Penaeus monodon) that encodes the bidentate RNAase III Dicer, a key component of the RNAi pathway. The full length of the shrimp Dicer (Pm Dcr1) cDNA is 7629 bp in length, including a 51 untranslated region (UTR) of 130 bp, a 3' UTR of 77 bp, and an open reading frame of 7422 bp encoding a polypeptide of 2473 amino acids with an estimated molecular mass of 277.895 kDa and a predicted isoelectric point of 4.86. Analysis of the deduced amino acid sequence indicated that the mature peptide contains all the seven recognised functional domains and is most similar to the mosquito (Aedes aegypti) Dicer-1 sequence with a similarity of 34.6%. Quantitative RT-PCR analysis showed that Pm Dcr1 mRNA is most highly expressed in haemolymph and lymphoid organ tissues (P 0.05). However, there was no correlation between Pm Dcr1 mRNA levels in lymphoid organ and the viral genetic loads in shrimp naturally infected with gill-associated virus (GAV) and Mourilyan virus (P > 0.05). Treatment with synthetic dsRNA corresponding to Pm Dcr1 sequence resulted in knock-down of Pm Dcr1 mRNA expression in both uninfected shrimp and shrimp infected experimentally with GAV. Knock-down of Pm Dcr1 expression resulted in more rapid mortalities and higher viral loads. These data demonstrated that Dicer is involved in antiviral defence in shrimp. (c) 2007 Elsevier Ltd. All rights reserved.

Main geochemical characteristics and key biogeochemical carbon processes in the East China Sea

Research related to carbon geochemistry and biogeochemistry in the East China Sea is reviewed in this paper. The East China Sea is an annual net sink for atmospheric CO, and a large net source of dissolved inorganic carbon to the ocean. The sea absorbs CO, from the atmosphere in spring and summer and releases it in autumn and winter. The East China Sea is a CO, sink in summer because Changjiang River freshwater flows into it. The net average sea-air interface carbon flux of the East China Sea is estimated to be about 4.3 X 10(6) t/y. Vertical carbon transport is mainly in the form of particulate organic carbon in spring; more than 98% of total carbon is transported in this form in surface water, and the number exceeds 68% in water near the bottom. In the southern East China Sea, the average particulate organic carbon inventory was about one-tenth that of the dissolved organic carbon. Research indicates that the southern Okinawa Trough is an important site for particulate organic carbon export from the shelf. The annual cross-shelf exports are estimated to be 414 and 106 Gmol/y for dissolved organic carbon and particulate organic carbon, respectively. Near-bottom transport could be the key process for shelf-to-deep sea export of biogenic and lithogenic particles.

A new species and key to known species of genus Oxya Serville (Orthoptera : Acrididae : Catantopinae) from China

During routine identification of the grasshoppers of the Dasa river, Guizhou Province of China in 2004, a new species [ Oxya guizhouensis sp, nov.] of the genus Oxya Serville ( Orthoptera, Acrididae, Catantopinae) was discovered. It is described here. A key to all known species of the genus from China is given. The type specimens are deposited in the Museum of Hebei University (MHU), Baoding, Hebei, China.

A new species and a key to known species of the genus Atractomorpha (Orthoptera, Acridoidea, Pyrgomorphidae) from China

A new species, Atractomorpha taiwanensis sp. n. from Taiwan, China, is described in this paper. The new species is similar to A. micropenna Zheng, 1992, but it differs from the latter by the following: lateral lobe of pronotum without membranous area near posterior margin; the tegmina strongly shortened, not reaching ( in male) the midpoint of hind femur; and wings very small, not reaching the midpoint of tegmina. A key to all known species of the genus Atractomorpha from China is given. The type specimens are deposited in the Museum of Hebei University, China.

A new species of Bryodema (Orthoptera : Acridoidea) from China, with a key to the described species

A new species Bryodema nigrofrascia of the genus Bryodema Fieber, 1853 (Orthoptera, Acridoidea, Acrididae Oedipodinae) from China is described. A key to known species of the genus is given. The type specimens are deposited in the Northwest Plateau Institute of Biology, Chinese Academy of Sciences, Xining, Qinghai.

末次盛冰期以来中国陆地生态系统碳储量变化研究

Carbon is an essential element for life, food and energy. It is also a key element in the greenhouse gases and therefore plays a vital role in climatic changes. The rapid increase in atmospheric concentration of CO_2 over the past 150 years, reaching current concentrations of about 370 ppmv, corresponds with combustion of fossii fuels since the beginning of the industrial age. Conversion of forested land to agricultural use has also redistributed carbon from plants and soils to the atmosphere. These human activities have significantly altered the global carbon cycle. Understanding the consequences of these activities in the coming decades is critical for formulating economic, energy, technology, trade, and security policies that will affect civilization for generations. Under the auspices of the International Geosphere-Biosphere Programme (IGBP), several large international scientific efforts are focused on elucidating the various aspects of the global carbon cycle of the past decade. It is only possible to balance the global carbon cycle for the 1990s if there is net carbon uptake by terrestrial ecosystems of around 2 Pg C/a. There are now some independent, direct evidences for the existence of such a sink. Policymarkers involved in the UN Framework Convention on Climate Change (UN-FCCC) are striving to reach consensuses on a 'safe path' for future emissions, the credible predictions on where and how long the terrestrial sink will either persist at its current level, or grow/decline in the future, are important to advice the policy process. The changes of terrestrial carbon storage depend not only on human activities, but also on biogeochemical and climatological processes and their interaction with the carbon cycles. In this thesis, the climate-induced changes and human-induced changes of carbon storage in China since the past 20,000 years are examined. Based on the data of the soil profiles investigated during China's Second National Soil Survey (1979-1989), the forest biomass measured during China's Fourth National Forest Resource Inventory (1989-1993), the grass biomass investigated during the First National Grassland Resource Survey (1980-1991), and the data collected from a collection of published literatures, the current terrestrial carbon storage in China is estimated to -144.1 Pg C, including -136.8 Pg C in soil and -7.3 Pg C in vegetation. The soil organic (SOC) and inorganic carbon (SIC) storage are -78.2 Pg C and -58.6 Pg C, respectively. In the vegetation reservoir, the forest carbon storage is -5.3 Pg C, and the other of-1.4 Pg C is in the grassland. Under the natural conditions, the SOC, SIC, forest and grassland carbon storage are -85.3 Pg C, -62.6 Pg C, -24.5 Pg C and -5.3 Pg C, respectively. Thus, -29.6 Pg C organic carbon has been lost due to land use with a decrease of -20.6%. At the same time, the SIC storage also has been decreased by -4.0 Pg C (-6.4%). These suggest that human activity has caused significant carbon loss in terrestrial carbon storage of China, especially in the forest ecosystem (-76% loss). Using the Paleocarbon Model (PCM) developed by Wu et al. in this paper, total terrestrial organic carbon storage in China in the Last Glacial Maximum (LGM) was -114.8 Pg C, including -23.1 Pg C in vegetation and -86.7 Pg C in soil. At the Middle Holocene (MH), the vegetation, soil and total carbon were -37.3 Pg C, -93.9 Pg C and -136.0 Pg C, respectively. This implies a gain of-21.2 Pg C in the terrestrial carbon storage from LGM to HM mainly due to the temperature increase. However, a loss of-14.4 Pg C of terrestrial organic carbon occurred in China under the current condition (before 1850) compared with the MH time, mainly due to the precipitation decrease associated with the weakening of the Asian summer monsoon. These results also suggest that the terrestrial ecosystem in China has a substantial potential in the restoration of carbon storage. This might be expected to provide an efficient way to mitigate the greenhouse warming through land management practices. Assuming that half of the carbon loss in the degraded terrestrial ecosystem in current forest and grass areas are restored during the next 50 years or so, the terrestrial ecosystem in China may sequestrate -12.0 Pg of organic carbon from the atmosphere, which represents a considerable offset to the industry's CO2 emission. If the ' Anthropocene' Era will be another climate optimum like MH due to the greenhouse effect, the sequestration would be increased again by -4.3 - 9.0 Pg C in China.