Significance of pollen and spores distribution to the barrier function of the Longitudinal Range-Gorge Region,Southwest China

35 surface soil samples and 28 profile soil samples were collected in Longitudinal Range-Gorge Region, Southwest China. The distribution of pollen and spores and their relationship with the environment are analyzed. The results show that there are significant differences in pollen and spores taxa, amounts, dominant taxa and florae between the eastern and western flanks of the Ailao Mountain. There are more pollen and spores taxa, a greater amount and complexity on the western flank of the mountain than those on the eastern flank, while the dominant taxa are more centralized and prominent on the eastern flank of the Ailao Mountain. As for the plant florae distribution, there are significant differences in the number of taxa and composition between the eastern and the western flanks. The analysis of profile pollen and spores assemblage shows that its trends of variation are basically in accordance with the surface pollen and spores, which are also indicators of the environmental differences between the two flanks of the mountain. These significant spatial differences of pollen and spores are very close to the regional topography and climate difference. The mountain running perpendicular to the moisture-laden air flow serves as a barrier and the monsoon circulations the east and the west of the mountain result in different energy-moisture characteristics. We conclude that the main patterns of the pollen and spores can be attributed to the environmental differences.

Effects of longitudinal range-gorge terrain on the eco-geographical pattern in Southwest China

China＇s southwestern special terrain pattern as parallel arrangement between lon- gitudinal towering mountains and deep valleys has significant effects on the differentiation of local natural environment and eco-geographical pattern in this region. The 1：50,000 Digital Elevation Model （DEM） data of Longitudinal Range-Gorge Region （LRGR）, meteorological observation data from the station establishment to 2010, hydrological observation data, Normalized Difference Vegetation Index （NDVI） and Net Primary Productivity （NPP） products of MOD13 and MOD17 as well as 1：1,000,000 vegetation type data were used. Moisture in- dices including surface atmospheric vapor content, precipitation, aridity/humidity index, sur- face runoff, and temperature indices including average temperature, annual accumulated temperature, total solar radiation were selected. Based on ANUSPLIN spline function, GIS spatial analysis, wavelet analysis and landscape pattern analysis, regional differentiation characteristics and main-control factors of hydrothermal pattern, ecosystem structure and function in this region were analyzed to reveal the effects of terrain pattern o~ regional dif- ferentiation of eco-geographical elements. The results show that： influenced by terrain pattern moisture, temperature and heat in LRGR have shown significant distribution cllaracteristics as intermittent weft differences and continuous warp extension. Longitudinal mountains and valleys not only have a north-south corridor function and diffusion effect on the transfer of major surface materials and energy, but also have east-west barrier function and blocking effect. Special topographic pattern has important influences on vegetation landscape diversity and spatiat pattern of ecosystem structure and function, which is the main-control factor on vegetation landscape diversity and spatial distribution of ecosystem. Wavelet variance analysis reflects the spatial anisotropy of environmental factors, NDVI and NPP, while wavelet consistency analysis reveals the control factors on spatial distribution of NDVI and NPP as well as the quantitative relationship with control degree. Special terrain pattern in LRGR is the major influencing factor on eco-geographical regional differentiation in this region. Under the combined effect of zonality and non-zonality laws with ＂corridor-barrier＂ functior as the main characteristic, special spatial characteristics of eco-geographical regional system in LRGR is formed.

Range of ecological impact of highway construction in the Longitudinal Range-Gorge Region,China

The major features of different road sections were identified.Methods quantitatively determining the ecological impact of highway construction were discussed,and a demonstration was presented.The Dabao highway(from Dali to Baoshan)and the Sixiao highway(from Simao to Xiaomengyang)passing through the Longitudinal Range-Gorge Region were used as examples in this paper.For the normal road sections having no important species to protect,a method of ecosystem health assessment was introduced to calculate the overall range of the ecological impact of highway construction.For the road sections having plants or soils of interest,indexes were selected and the range of impact was determined using mathematical methods such as regression analysis and variance analysis.The range of impact on animal populations was also discussed in terms of the minimum living areas required by animal populations and the fragmentation caused by highway construction.The results indicate that the zones impacted by highway construction were composed of both regular and anomalous figures,the range of impacts for different landforms of the two sample highways were substantially different;highway construction had dramatic effects on roadside ecosystem health;the impact on soil factors of farmland was greater than 200 m,and the distance may exceed 1000 m when important large animals were considered.

Mechanism of the effect caused by highway construction on plant biomass in Longitudinal Range-Gorge Region

Taking Dabao （from Dali City to Baoshan City, Yunnan Province, China） and Sixiao （from Simao City to Xiaomengyang Town, Yunnan Province, China） highways in Longitudinal Range-Gorge Region as examples. Biomass, coverage and photosynthesis rate of different plant types on sampling points （at the distances from road of 5, 20, 40, 80, 120 and 200 m） and their control points were estimated on ground. The relations among biomass, coverage, photosynthesis rate were analyzed with an aim to explore the mechanism of the effect caused by highway construction on plant biomass. The results show, i） the impacts of highway construction on plant biomass are both positive and negative. Arbor is mainly negatively impacted, while shrub and herbage are mainly positively impacted. The effect of highway construction decrease with the increase of distance from the road; ii） highway construction exert obvious influence on plant biomass through altering the physiologic processes （reflected by the plant number） and photosynthesis, iii） highway construc- tion will result in the decrease of arbor number, photosynthesis rate and biomass, and increase of plant number, photosynthesis rate and biomass of shrub and herbage.

Spatial and temporal variation of runoff of Red River Basin in Yunnan

This paper studies the variation of runoff of Red River Basin and discusses the influence of＂corridor-barrier＂functions of valleys and mountains on variation of runoff by using GIS and statistic methods based on the monthly precipitation,temperature and evaporation data from 1960 to 2000 at 32 meteorological stations in Red River Basin,and the annual runoff data of Yuanjiang River,Lixian River and Panlong River from 1956 to 2000.The results show out：（1）Under the effect of＂corridor-barrier＂functions of valleys and mountains in Red River Basin,the patterns of annual precipitation and runoff depth distribution in spatial change a NW-SE direction,which is similar with the trend of the Red River valley and Ailao mountains.（2）In the long temporal scale averaged over years,the most obvious effects of the＂corridor-barrier＂functions is on runoff variation,and the second is on the precipitation, but not obvious on the temperature.（3）Under the superposed effect of climate changes and the＂corridor-barrier＂functions of valleys and mountains in Red River Basin,the difference of runoff variation is obvious in the east-west direction：the runoff variation of Yuanjiang River along the Red River Fault present an ascending trend,but the Lixian River on the west side of the Fault and the Panlong River on the east present a descending trend;the annual runoff in Yuanjiang River and Panlong River had a quasi-5a periods,and Panlong River had a quasi-8a periods;the runoff variation are quite inconsistent in different periods among the three river basins.

Research Agenda for Understanding Transboundary Ecosystem Changes and Eco-security in Southwestern China

The longitudinal range-gorge region (LRGR) in Southwestern China, characterized by longitudinal mountain ranges and deep valleys, includes the basins of four major international rivers: the Yuanjiang-Red, Lancang Mekong, Nujiang Salween and Irrawaddy. This region is classified as one of the world’s biodiversity hotspots, and provides an important ecological and economic corridor linking China and Southeast Asian countries. Over the past half century, it has served as a resource base for timber and minerals needed to fuel economic development, which resulted in rapid and drastic changes in ecosystem and species diversity. Proposed and ongoing development programs, such as China’s Great Western Development campaign, Greater Mekong Subregional Economic Cooperation (GMS) and China-ASEAN free trade zone development (“10+1”), threaten to bring unprecedented disturbance to the region’s ecosystems. Present and emerging threats to eco-security have caught tremendous attention worldwide. Therefore, studies on such problems are critical for enhancing ecosystem health and transboundary eco-security. This paper indicates several multi-disciplinary and cross-sector studies on transboundary resources in this region that will meet three major national needs: 1) identifying core scientific issues of ecological development and infrastructure construction in highplateau and mountainous areas for the Western Development campaign; 2) developing maintenance mechanisms and control methodologies for transboundary eco-security and resource base development; 3) providing scientific grounds for multi-lateral diplomacy, trade and economic cooperation, and conflict resolution as part of China’s opening-up to south Asia. The key subjects to be solved include dynamics and major drive forces of this area, ecological effects caused by major projects construction, and transboundary eco-security and its controlling. The research projects proposed in this article will develop theories on ecosystem change and transboundary eco-security, and provide a scientific basis for national and international development strategies.

Relationship between Surface Pollen and Modern Vegetation in Southwestern China

Based on the pollen data obtained from thirty-five surface soil samples and investigated vegetation data from seven plant quadrats,the quantitative relationship between surface soil pollen and modern vegetation are studied in the longitudinal range-gorge region (LRGR) in Southwestern China.R-values (referring to pollen assemblages) are calculated with pollen percentage and plant abundance.The coefficients of similarity between pollen and vegetation are analyzed.The results show that the pollen assemblages on surface soil of all vegetation zones can basically represent the native vegetation,but the pollen assemblages are not fully according with the vegetation.This is due to the influencing factors including pollen preservation ability,pollen production,amount of exotic pollen and pollen identification.The pollen representation in surface soil is different in families and genera.The pollen of woody plants such as Pinus,Tsuga,Alnus,Fagus and Castanopsis are over-representative,but those of Quercus,Carpinus Myrica,Elaeocarpaceae,Ericaceae,Theaceae and Llex are underrepresentative;the pollen of herbaceous plants such as Artemisia and Rubiaceae are over-representative,while those of others including Gramineae and Araliaceae are under-representative.The R-values of the same taxon pollen in different vegetation zones are different,depending on their distances from the pollen sources.The coefficients of the similarity between plant communities and pollen assemblages are mostly over 70%,which indicate again that the surface soil pollen and spores assemblages can represent the vegetation.It is concluded that there is a good corresponding relationship between surface pollen assemblages and native vegetation in LRGR,and it is of great significance for reconstructing the past vegetation and paleoclimate using quantitative fossil pollen data in this region.

Temporal and spatial changes of agricultural water requirements in the Lancang River Basin

Based on the data of eight meteorological stations from the 1950s to 2007, current cropping patterns, field water moisture management, we use the Mann-Kendall and the Rescaled Range Analysis methods to research the changes of humidity and crop irrigation water requirements in the Lancang River Basin. The results show that the annual and dry season average temperatures significantly increased, and the dry season rainfall increased while wet season rainfall decreased. Evaportranspiration （ETo） increased during both dry and wet seasons at all stations except Dali, Jianchuan and Gengma, and the aridity-humidity index decreased at most of the stations. The turning points of weather factors, ETo, the aridity-humidity index, paddy irrigation requirements and total agricultural water requirements occurred from the 1960s to the 1990s. The spatial changing tendency of paddy irrigation quota increased with the increase of altitude and latitude, and the correlation coefficients are 0.513 and 0.610, respectively. The maximum value is observed in Weixi, while the minimum in Mengla.