Longitudinal Range-Gorge Region Research Articles

Determinants of Genetic Structure in a Highly Heterogeneous Landscape in Southwest China.

Intra-specific genetic diversity is a fundamental component of biodiversity, and is key to species adaptation and persistence. However, significant knowledge gaps still exist in our understanding of the patterns of genetic diversity and their key determinants. Most previous investigations mainly utilized single-species and/or a limited number of explanatory variables; so here we mapped the patterns of plastid genetic diversity within 15 plant species, and explored the key determinants shaping these patterns using a wide range of variables. Population-level cpDNA sequence data for 15 plant species from the Longitudinal Range Gorge Region (LRGR), southwest China, were retrieved from literature and used to estimate haplotype diversity (HD) and population pairwise genetic differentiation (FST) indices. Genetic diversity and divergence landscape surfaces were then generated based on the HD and FST, respectively, to clarify the patterns of genetic structure in the region. Subsequently, we analyzed the relationships between plastid genetic diversity and 16 explanatory variables (classified as anthropogenic, climatic, and topographic). We found that the highest genetic diversity occurred in the Yulong Mountain region, with a significant proportion (~74.81%) of the high diversity land area being located outside of protected areas. The highest genetic divergence was observed approximately along the 25°N latitudinal line, with notable peaks in the western and eastern edges of the LRGR. Genetic diversity (HD) was weakly but significantly positively correlated with both Latitude (lat) and Annual Mean Wet Day Frequency (wet), yet significantly negatively correlated with all of Longitude (long), Annual Mean Cloud Cover Percent (cld), Annual Mean Anthropogenic Flux (ahf), and Human Footprint Index (hfp). A combination of climatic, topographic, and anthropogenic factors explained a significant proportion (78%) of genetic variation, with topographic factors (lat and long) being the best predictors. Our analysis identified areas of high genetic diversity (genetic diversity “hotspots”) and divergence in the region, and these should be prioritized for conservation. This study contributes to a better understanding of the features that shape the distribution of plastid genetic diversity in the LRGR and thus would inform conservation management efforts in this species-rich, but vulnerable region.

Identification and monitoring landslides in Longitudinal Range-Gorge Region with InSAR fusion integrated visibility analysis

In high mountain canyon regions, SAR geometric distortion in imaging side may have an inevitable impact on InSAR deformation information, so the effective deformation information acquisition is critical for landslide identification and deformation mechanisms analysis. The landslide deformation around the reservoir of Gushui Hydropower Station located in upstream of the Lancang River has been focused on in the study. Using SAR satellite parameters and topographic information, the visibility analysis of deformation in radar line-of-sight (LOS) direction has been carried out, and a method to obtain LOS effective deformation information based on the visibility analysis has been proposed. The small baseline subsets (SBAS) technique is used to process the L-band and C-band SAR data, and the area affected by the geometric distortion in the InSAR result is masked to obtain the deformation information of the effective deformation region. The landslide identification analysis in the reservoir area has been carried out based on the effective deformation information in LOS direction. Thirteen landslides have been identified, and ten of them are new ones. A new large unstable area (New Zhenggang landslide) has been found near the Zhenggang landslide. The geological survey and displacement time series of the Zhenggang landslide reveals that it is in pull-type landslide mode, that is, due to the local instability of the leading edge of a landslide, the support of the trailing edge may be weakened, which may result in the landslide gradually developing backwards and upwards, and finally becoming a large landslide. The impact of peak rainfall and cumulative rainfall during the rainy season on landslide deformation has been verified in this paper. It indicates that the cumulative precipitation is the dominant factor causing the deformation of the landslide, and it shows that the landslide begins the deformation acceleration period about 12 days after the peak precipitation. The results have shown that the proposed visibility analysis method for extracting the effective deformation information of InSAR results can significantly improve landslide identification and analysis in complex terrain.

Spatiotemporal variation in vegetation coverage and its response to climatic factors in the Red River Basin, China

Vegetation coverage is a critical factor in soil conservation and improving the ecological environment. As an important ecological corridor connecting China's southwest and Southeast Asia, the Red River Basin is characterized by vulnerable ecosystems and serious soil erosion. Identifying the heterogeneity in vegetation coverage and its response to climatic factors are critical for ecological protection and soil and water conservation. MOD13Q1 NDVI data with a spatial resolution of 250 m and 16 d temporal resolution were collected from 2000 to 2014. The maximum synthesis method, univariate linear regression, Hurst exponent, and partial correlation analysis were used to detect the spatiotemporal variation and sustainability of vegetation coverage and characterize the relationship between vegetation NDVI and climatic factors in the wet season in the Red River Basin. NDVI showed a rather significant increasing trend in the wet season. The “corridor-barrier” function of valleys and mountains affected the spatiotemporal patterns in the Longitudinal Range-Gorge Region. Areas of improved, degraded, and stable vegetation coverage accounted for 50.1%, 27.1%, and 22.8% of the total, respectively. The role of precipitation was higher than temperature in the interaction between NDVI and climatic factors. A time lag effect was found in the NDVI response to rainfall and temperature variation. Different vegetation types showed various spatiotemporal responses to climatic factors. Human activities, especially the implementation of the Grain for Green Project (GFGP), affected the spatial and temporal patterns of vegetation coverage.

Variations and trends of trans-boundary runoff in the longitudinal range-gorge region

The mountainous hydrological process usually shows high variation to climate change and human action. In the Longitudinal Range-Gorge Region (LRGR), Southwestern China and Southeast Asian, the transboundary runoff variations are much more sensitive and complex under the interaction of climate change, “corridor-barrier” functions in LRGR, and dams building. In this paper, based on the long hydrological records (1956-2013) from three mainstream hydrological stations in Nu River, Lancang River, and Red River, the region runoff variations were analyzed. The results show out: i) the regional runoff changes were strongly influenced by the “Corridor-Barrier” functions in LRGR from west to east, the variability extent of annual runoff increased, but tended to decrease after 2009 and the reduced extents also increased; ii) the annual runoff change in the three rivers had high concentration degrees; iii) there were periodicities of 33 years of runoff change in Nu River and Lancang River, and 30 years in Red River, and the lower flow period would continue for 8-9 years in Nu River and Lancang River but only for 4 years in Red River; iv) since 2010, as the two mega dams of Xiaowan and Nuozhadu built in Lancang River mainstream, their variations of annual runoff were quite different. The research results could offer a scientific base for sustainable utilization, conservation, and management of the regional water resources

Recent spread and climatic ecological niche of the invasive guava fruit fly, Bactrocera correcta, in mainland China

The guava fruit fly, Bactrocera correcta (Bezzi) (Diptera:Tephritidae), is a harmful exotic insect pest in mainland China, which was first recorded in Yuanjiang County of Yunnan province in 1982. In order to elucidate its rate of spread, extensive field surveys were conducted during 2003–2011. Through 2011, B. correcta was found in areas below 1,500 m in altitude within the Longitudinal Range-Gorge Region of southwestern China (21–28°N latitude, 97–107°E longitude). The northernmost site where B. correcta was found was in Miyi County (26.48°N Latitude, 102.00°E longitude, Alt. 1,060 m) in Sichuan province. Within the currently infested area of mainland China, B. correcta mainly occurred in low-altitude valleys and basins, and displayed a patchy distribution. The mountain chains tend to run south to north, forming a natural barrier to insect flight eastward and westward. Human-assisted transport of infested fruits was the likely factor by which B. correcta moved across mountain chains. The analysis indicated that high-altitude portions of the northern Longitudinal Range-Gorge Region may block B. correcta spread northward.

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 construction 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.

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

China’s southwestern special terrain pattern as parallel arrangement between longitudinal 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 indices including surface atmospheric vapor content, precipitation, aridity/humidity index, surface 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 on regional differentiation of eco-geographical elements. The results show that: influenced by terrain pattern, moisture, temperature and heat in LRGR have shown significant distribution characteristics 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 spatial 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” function as the main characteristic, special spatial characteristics of eco-geographical regional system in LRGR is formed.

The cumulative effects of dam project on river ecosystem based on multi-scale ecological network analysis

The importance of addressing cumulative environmental impact of large development projects on rivers has been increasingly highlighted. Consideration to potential impact pathways may be difficult, however, without appropriate analytical methods. By introducing ecological network model, this paper focuses on the quantification of the cause-effect relationships inherent the cumulative effects of dam construction from a holistic perspective. With Lancang river of Longitudinal Range-Gorge Region (LRGR) as an example, the risk-based interaction instead of the conventional energy or material flow of ecological network model has been created to conceptualize the cumulative effects network model. Based on this model, the network structural and functional analysis were adjusted for the assessment of potential eco-environmental impact within the ecosystem, thus demonstrating how the risk-based ecological network analysis can be used to characterize the holistic cumulative effects of dams on the temporal and spatial scale.

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.

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.

Modern pollen distribution and its relationship with environmental difference in southwestern China

Quantitative relationships between pollen and vegetation in the Longitudinal Range-Gorge Region (LRGR) are studied based on the pollen records of 35 surface soil samples and 7 vegetation quadrates. The spatial distribution of the pollen and the relative control of environmental factors are analyzed. Results are: (1) The R values, which designate the representation of pollen to vegetation, indicate a good quantitative relationship between surface pollen assemblages and local vegetation. (2) Significant differences in diversity of pollen flora, pollen amounts, major taxa, and vegetation between the east and the west sides of Ailao Mountain, an important geographical dividing line in LRGR, are recognized. (3) Obvious spatial differences of pollen assemblages are relevant to different regional topography and climatic conditions. These results suggest that the spatial differences between pollen assemblages would be caused by the different pattern of hydrothermal condition in the unique topography of the LRGR. The barrier function of the vertical mountain ranges, especially by the Ailao Mountain, may be a main factor in such environmental differences. Two separate monsoon circulations occurring in Pacific and Indian oceans result in different hydrothermal characteristics causing the regional differentiated patterns in the pollen assemblages in the study area.

The distribution of heavy metal in surface soils and their uptake by plants along roadside slopes in longitudinal range gorge region, China

Metal distributions (Cd, Cr, Cu, Ni, Pb and Zn) in the soils and plants were investigated in roadside surface soils and grass herbage collected from two study sites adjacent to Mangshi–Ruili and Dali–Baoshan highways. At each study site, soil and plant samples were collected along two roadside slopes with distances of 5, 10, 20, 50, 100, and 200 m away from the highway. Results show that the enrichment of heavy metals in the surface soils and plants along the road is caused by the highway, and it decreases with the increasing distance from the road. Metal concentrations in the soils and plants along the downslope are higher than those in the upslope along the road. The six types of metals investigated in this research mainly distributed within 200 m from the highway. Four types of relationships between metal uptake by plants from soils and the distance were found and their clear distinctions of Cr, Cu, Pd, Ni and Zn uptake by plants were also investigated.

Landscape pattern changes under the disturbance of road networks

Road ecologists have dedicated their efforts in analyzing the interactions between road networks and the surrounding landscape ever since the establishment of Road Ecology. The understanding of the interactions has been promoted by the proposed quantification parameters of road networks’ impacts such as road density, buffer zone and so on. Using these parameters, we analyzed the road network's disturbance effect on the landscape pattern with the newly proposed index-RV (Roadless Volume) in the study. Based on the sampling of square quads all over the Longitudinal Range-Gorge Region (LRGR) during 1980-2000, the changes of the different patches such as forest, grassland, cropland and urban land under different disturbance degrees of road networks classified by RV value have been examined. The results showed that: the decreased area and number of forest and arable patches changed with the disturbance degree of road networks’ logarithmically; The area and number of grassland decreased at the highest disturbance level but increased in some lower disturbance level; The area of urban land increased at the high disturbance level which followed the logarithmical trend with the disturbance level. These results imply that the road networks generally transformed the landscape pattern from the forest and cropland to large patch of urban land surrounding roads.

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.

Prediction of river ecological integrity after cascade hydropower dam construction on the mainstream of rivers in Longitudinal Range-Gorge Region (LRGR), China

Dam construction is considered the major factor contributing to significant modification of river ecosystems. The related ecological effects of these constructions on flow patterns, water quality, sediment etc. have led to increased concerns in recent years. Most of the works so far focus on the assessment of vulnerability, risk, and damages to single factors, such as soil conservation, fish reproduction or vegetation. Few works have been done on to analyzing and predicting the changes of the river ecosystem integrity ( REI). Taking three important international rivers, Lancang River, Nu River and Yuan River in LRGR as a case study, the relationship between cascade dam construction and REI is analyzed. A model of the cascade dam construction and the REI is developed on Lancang River after cascade construction, and then it is applied on the Nu River and Yuan River to predict the changes of REI after the planned cascade construction. The results show that there are significant relationships between the cascade construction and the change of the REI. Before the cascade development, REI index of Nu River is the highest with a value of 0.844. Yuan River, the worst of the three before the cascade construction (0.719), is found to be the best one after the cascade construction (0.389). After the cascade construction, the REI index value of the Lancang River is likely to dramatically decrease from 0.825 to 0.274.

Disturbance of Dabao highway construction on plant species and soil nutrients in Longitudinal Range Gorge Region (LRGR) of Southwestern China

The disturbance of highway construction upon surrounding vulnerable ecosystems is a common threat in the Longitudinal Range Gorge Region of southwestern China. We evaluated the disturbance of highway on plant species richness and diversity and soil nutrients from adjacent to the highway to 300 m upslope and 100 m downslope in forests and grasslands by setting 12 belt transects in forests and grasslands (six belt transects and six control belt transects, respectively). The results showed that there were some significant variances in belt transects with respective control belt transects for species richness and diversity in both forests and grasslands. Species richness and diversity of trees were lower within a 50-m distance from the highway and more noticeable on the downslope portion. Species richness and diversity of shrubs and herbs appeared higher near highway edge. Both species richness and diversity of herbs were similar in forests. In addition, exotic species, such as Eupatorium adenophorum, were further from the road and more widely dispersed in grasslands. Soil nutrients except total potassium (TK) were lower in the downslope area adjacent to highway edge and showed a significant increase with increasing distance from the highway in both forests and grasslands. This indicates that grasslands acted as microhabitats for exotic species and are more easily to be invaded than forests, especially if disturbed. Once destroyed, plant species and soil nutrients will require a significant amount of time to be restored to control levels. This work illustrates that the effects extend considerably to distances upslope and downslope from the construction site. Given that these changes occurred relatively quickly, the study suggests that the environmental "footprint" grows far beyond the road and adjacent zone of disruption.

Ecological Water Requirement (EWR) Analysis of High Mountain and Steep Gorge (HMSG) River—Application to Upper Lancang–Mekong River

As “corridor” in the south–north and “barrier” in the west–east direction, Lancang River, the upstream of Lancang–Mekong River, has an obvious spatial–temporal characteristic and unique regional attributes. Recently, the hydropower development of the mainstream along Lancang River has disturbed the regional ecosystem to have unstable factors, and threatened the ecosystem health. This paper used the couple model of Grading Coefficient of ecological water requirement (GCEWR) and the ecological runoff (ER) to simulate the ecological water requirement (EWR) of Lancang River, in a broad sense, this method belongs to hydrology–ecology methodology. In the GCEWR–ER, We adopted ecological characteristic indexes (ECI) and hydrological characteristic variables (e.g. variance index) to calculate the GCEWR, and used three methods to calculate the basic variable (e.g. ER) of EWR: the first method directly used annual average runoff as ER; the second method was used frequency method and took year as basic time unit, and the third method took season (e.g. flood season, non-flood season) as the basic time unit to evaluate ER. Finally, in order to demonstrate applicability of this developed methodology, this paper adopted GCEWR–ER method to calculate the EWR of Lancang River in the Longitudinal Range-Gorge Region. By the systematic analysis of the results, we could get the minimum, satisfying and optimal EWR for the Lancang River, which were 142.53 × 108, 286.46 × 108 and 385.96 × 108 m3. The three EWR respectively occupied 25.10%, 50.46% and 67.98% of the average measured run-off (567.75 × 108 m3) of the Lancang River, and respectively occupied 18.63%, 37.45% and 50.45% of the natural run-off (765 × 108 m3) of the Lancang River.

Definition and Spatial Differ entiation of Road- effect Zone: A Case Study in Longitudinal Range- Gorge Region

Taking road network in Longitudinal Range-Gorge Region(LRGR) as an case study,we got the bound of road-effect zone through overlay method of GIS considering its influencing factors.Then we calculated the percentage of road-effect zone area in certain region and study the spatial variability in LRGR.Further,road density,population density,village number,ecological capacity and average altitude were selected to analyze their relationship with road effect zone.The results showed that different road types had various road-effect zones.Spatial contribution of road effect showed a great regional difference.The effect zone decreased from Kunming to region around.Honghe River Valley had a higher value than Lancang and Nujiang River Valley.In LRGR,there showed significant spatial convergence region in east,north and south-west of LRGR.Correlation analysis showed that there existed significant correlation between road-effect proportion and road density,population density,village number,ecological capacity while no correlation with average altitude.

English

  Deforestation, over-cultivation and rural growth have severely damaged native vegetation of woodlands along roadsides in the Longitudinal Range-Gorge Region of Yunnan Province. This study was conducted to evaluate the effect of different reforestation practices, which consisted of natural restoration or planting with tree seedlings that varied in species composition, coverage and diversity, on damaged roadside woodlands. Three randomly selected 10 m x 10 m plots in each reforestation practice were investigated. The results showed that the species composition, plant cover and species diversity of the planted communities varied with reforestation strategies and time since planting. A higher number of species, proportion of native species and woody plants, canopy cover and species diversity were found in naturally restored plots and in 3 - 4 year old plots that were planted with native plants. In the early stages of reforestation, herbs dominated the plant community in most plots, and woody plants became more important with time after reforestation. Preliminary results suggest that plant height can be used an auxiliary indicator of plant cover to assess ecosystem function status of the restoration project. Also, evenness may be easier to restore than species richness. Natural restoration or reforestation with native dominant plants is a good management strategy for vegetation restoration or improvement.   Key words: Vegetative characteristics, plant community, restoration, Southwest China.

Research on spatiotemporal change of ecological capacity and driving forces in the LRGR

The Longitudinal range-gorge region (LRGR) is a key region for biodiversity protection in China. Also it is notable for rich resources, complex environment and vulnerable ecosystem. In the LRGR, there are great differences in ecological security level and ecological capacity. Human disturbance and ecosystem changes are significant. Analyzing the spatiotemporal changes of ecological capacity is of importance for government to implement ecological management. Taking the counties in the LRGR core region as a case, with the help of GIS, we used ecological footprint method to study the spatiotemporal change of ecological capacity at two scales—the larger scale of city and smaller scale of county. Then we discussed the driving factors that affected ecological capacity by principal component analysis (PCA). The results showed that the ecological footprint, ecological capacity and ecological security level varied distinctly from county to county in the LRGR. Regional ecological capacity decreased year by year from the north, south to the middle of LRGR. According to the analysis of driving forces, per capita ecological capacity had a negative correlation with population, GDP, and other driving factors. Among these factors, social economy and population had very significant impacts on ecological capacity. And the spatial variation of driving factors determined the spatiotemporal change of ecological capacity.