Chinese Journal of Applied Ecology

Simulation on the control effect of low impact development measures of sponge city based on storm water management model (SWMM)

LI Chun-lin, LIU Miao, HU Yuan-man, SUI Jin-ling, WU Yi-lin, LIU Chong, SUN Feng-yun

2017, 28(8): 2405-2412. doi:10.13287/j.1001-9332.201708.002

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In order to solve the problems of water ecology, water security and water environment in the process of urbanization, sponge city, the new urban storm water management concept, was put forward based on the low impact development (LID). The Chicago rain type formula and Shenyang rainfall intensity formula were used to form Shenyang rainfall process line of different return periods. The water quantity and quality processes of the three scenarios, before urbanization, after urbanization and after setting LID measures, were simulated and analyzed by storm water management model (SWMM). The results showed that with the increase of rainfall return period, the reduced runoff volume of LID measures was gradually increased, and the runoff volume was close to that before urbanization. LID measures removed lots of TSS and COD, but their emissions were still higher than that before urbanization, while that of TN and TP were close to that before urbanization. With the increase of the rainfall intensity, the runoff velocity increased, but the removal of TSS, TP and COD by LID measures decreased gradually.

Spatiotemporal variations of growing-season NDVI and response to climate change in permafrost zone of Northeast China

GUO Jin-ting, HU Yuan-man, XIONG Zai-ping, YAN Xiao-lu, REN Bai-hui, BU Ren-cang

2017, 28(8): 2413-2422. doi:10.13287/j.1001-9332.201708.005

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Permafrost is extremely sensitive to climate change. In particular, aboveground vegetation on permafrost has great sensitivity to the change. The permafrost zone of Northeast China, within middle and high latitudes of the Northern Hemisphere, is the second-largest region of permafrost in China. It is at the southern edge of the Eurasian cryolitho zone. This study analyzed growing-season spatiotemporal variation of the normalization difference vegetation index (NDVI) in this permafrost zone and the correlation between NDVI and climate variables during 1981-2014 based on LTDR, MODIS data set and meteorological data. Mean growing-season NDVI significantly increased by 0.0036 a^-1 over the entire permafrost zone. The spatial dynamics of vegetation cover in the zone had strong heterogeneity on the pixel scale. NDVI showing a significant (P<0.05) increasing trend accounted for 80.6% of the permafrost area, and NDVI showing a significant (P<0.05) decreasing trend accounted for 7.7% of the entire study area. The trend of NDVI was variable in different kinds of permafrost zones which increased in order of continuous permafrost zone>discontinuous permafrost zone>sparse island permafrost zone>seasonal frozen region. The proportion of area for maximum increasing trends of NDVI (>0.004) in different permafrost regions was in order of continuous permafrost zone>discontinuous permafrost zone>sparse island permafrost zone>seasonal frozen region. Additionally, at the entire permafrost zone scale, the mean growing-season NDVI was positively significantly correlated with growing-season mean temperature (r=0.79, P<0.01), but weakly negatively related with growing-season precipitation, which indicated that temperature was the dominant influence on vegetation growth during the growing season in the study area. Permafrost degradation in the study area played a positive role in plant growth, especially in continuous permafrost zone and discontinuous permafrost zone. Although increasing ground surface temperature accelerated vegetation cover and growth in the short time, from the long term point of view, permafrost degradation or disappear might hinder vegetation growth.

Impact of land pavement on photosynthetic characteristics of common greening trees in Beijing, China

WANG Xu-ming, CHEN Yuan-yuan, WANG Xiao-ke

2017, 28(8): 2423-2430. doi:10.13287/j.1001-9332.201708.014

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Land pavement has impacted urban tree growth and its ecosystem service, and it is necessary to investigate the key physiological processes of urban trees grown under land pavement. To study the impact of land pavement on photosynthetic characteristics of common greening trees in Beijing, a field experiment was designed with three treatments: the control (the non-paved), pervious pavement and impervious pavement, and the leaf net photosynthetic rates and related physiological-ecological parameters of two common greening trees (Fraxinus chinensis and Acer truncatum) in Beijing were measured in the 4^th year after planting. Results showed that the photosynthesis of F. chinensis and A. truncatum showed different responses to different types of pavement, the net photosynthetic rate was significantly decreased for F. chinensis under both pervious and impervious pavements and for A. truncatum only under impervious pavement. The air relative humidity and soil volumetric water content under pervious and impervious pavements were lower than that under the control, which reduced water amount available for trees. The lower net photosynthetic rates of F. chinensis and A. truncatum under impervious pavement were mainly attributed to the decrease in leaf stomatal conductance. The PSⅡ effective photochemical quantum yield (F_v′/F_m′) of F. chinensis was significantly lower under pervious and impervious pavements, while the PSⅡ actual photochemical quantum efficiency (Φ_PSⅡ) and apparent electron transport rate (ETR) of A. truncatum were significantly higher under impervious pavement.

Characteristics of sap flow of two typical trees in exposed bedrock habitat of Karst region, China

ZHANG Hui-ling, DING Ya-li, CHEN Hong-song, WANG Ke-lin, NIE Yun-peng

2017, 28(8): 2431-2437. doi:10.13287/j.1001-9332.201708.013

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A unique but very common habitat, rocky outcrop in Karst region of southwest China was selected for this study. Sap flow patterns of two typical tree species (Radermachera sinica and Triadica rotundifolia) were analyzed by using the method of Granier’s thermal dissipation probe (TDP). The results showed that sap flow density of both species exhibited clear response to the wet and dry seasons. However, the absence of sap flow only last about 1 month for R. sinica but 4 months for T. rotundifolia, despite the same functional type of these two species. T. rotundifolia consumed relatively higher annual total amount of water per unit area at breast height than R. sinica. Moreover, water that was consumed during the growing season (from April to September) accounted for 90% and 66% of the annual total amount for T. rotundifolia and R. sinica, respectively. Sap flow densities of the two species were very significantly positively correlated with photosynthetically active radiation, water vapor pressure deficit, and temperature, while had very significant negative correlation with air relative humidity. Sap flow densities and daily water consumptions of two tree species were not only lower than the tree species distributed in the same climatic non-karst zone of the study area, but also lower than the main tree species in karst area nearby, and even lower than the typical species in dry area with extremely low precipitation. The above results suggested that water consumption of the two tree species were restricted by the specific water environment of rocky outcrop, and species of the same functional type exhibited different water use strategies.

Application of the penta-needle heat pulse probes to determine the stem sap flow

DU Meng-ge, WANG Sheng, FANG Jun

2017, 28(8): 2438-2444. doi:10.13287/j.1001-9332.201708.035

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It is very important to measure sap flow accurately for investigating water consumption characteristics of trees, plant physiology and eco-hydrology. A new multifunctional digital penta-needle heat pulse probes (PHPP) was selected in this study, which was used to measure the sap flow of the Lobular poplar, in order to test the applicability and reliability of the new penta-needle heat pulse sensors in the measurement of sap flow in comparison with the thermal diffusion method (TDP). The results showed that PHPP can accurately obtain the diurnal variation of the sap flow of the Lobular poplar and the results had statistically significant linear correlation with TDP, with R²being 0.90, root mean square error 2.75 and mean relative error 11%. PHPP could accurately identify low and reverse sap flow, with the thermal parameters being fitted quickly and accurately. It was a promising method to measure sap flow.

Effect of sap flow radial variation on daily transpiration estimation of Eucalyptus urophylla× Eucalyptus grandis

ZHOU Cui-ming, GU Da-xing, ZHAO Ping, HUANG Ke-chao, HE Wen, YAO Yue-feng, ZHU Li-wei, HUANG Yu-qing

2017, 28(8): 2445-2451. doi:10.13287/j.1001-9332.201708.032

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The sap flow velocity of Eucalyptus urophylla × Eucalyptus grandis was measured at 0-2 cm and 2-4 cm sapwood depths using the Granier-type thermal dissipation probe (TDP) method to determine the effect of sap flow radial variation on whole-tree daily transpiration estimation, the estimation errors of different diameters at breast height (DBH), and the relationships between the estimation errors and photosynthetically active radiation (PAR) and vapor pressure deficit (VPD). Results showed that the daily transpiration of E. urophylla×E. grandis estimating with one point sap flow velocity at 0-2 cm was the highest, followed by the two points estimated value obtained from 0-2 cm and 2-4 cm, and that with one point sap flow velocity at 2-4 cm being the minimum. Compared to the two points estimated value, the sap flow velocity of 0-2 cm and 2-4 cm were overestimated by 32.9% and underestimated by 58.7%, respectively. The estimation error with one-point sap flow velocity of 0-2 cm decreased along with the decreasing DBH. The estimation errors were 51.7%, 33.0% and 18.0% at DBH 17.7, 12.9 and 9.8 cm, respectively. The estimation error with the 2-4 cm sap flow velocity did not show significant difference among trees with different DBHs. There was a good positive correlation between estimation error and PAR and VPD when one-point sap flow velocity was used at 0-2 cm. Compared to the traditional method using only one point sap flow velocity, it was better to use multiple points estimate of sap flow velocity for a more accurate estimation of daily transpiration of E. urophylla × E. grandis. Our results provided a reliable estimate of water use in Eucalyptus plantation.

Spatio-temporal distribution characteristics of forest litterfall in China

SHEN Guang-rong, XIANG Qiao-qiao, CHEN Dong-mei, WU Yu, LIU Chun-jiang

2017, 28(8): 2452-2460. doi:10.13287/j.1001-9332.201708.026

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In this study, the relationship models at national scale between forest litterfall (and leaf litterfall) and climatic factors (mean annual mean temperature, MAT; mean annual precipitation, MAP; and actual evapotranspiration, AET) were constructed. The spatial and temporal distribution patterns of forest litterfall and leaf litterfall in 2001, 2006 and 2012 were investigated by using geostatistical analysis combining with forest cover information based on remote sensing interpretation. Results indicated that the variation in litterfall and leaf litterfall were well explained at regional scales by AET than MAT and MAP. Evergreen broadleaf forest distributing mostly in South Central China possessed the highest mean yearly litterfall (636.2 g·m^-2), and that of deciduous broadleaf forest in the Northeast of China was between 339-385 g·m^-2. The forest leaf litterfall accounted for about 70% of total forest litterfall. The total forest litterfall in China increased from 801 Tg in 2001, and 865 Tg in 2006 to 1032 Tg in 2012, meanwhile, the forest coverage in China also presented an increasing trend, 18% in 2001, 20% in 2006, and 24% in 2012. The rapid increase of plantation area and stand growth in China had a great effect on the forest litterfall and its dynamic change, and the material cycle of forest ecosystem.

Simulating canopy reflectance time series for typical subtropical forest by coupling PROSPECT5 and 4SAIL models

ZHANG Lu-ying, LI Xue-jian, DU Hua-qiang, CUI Lu, MAO Fang-jie, LIU Yu-li, LI Yang-guang, ZHU Di-en

2017, 28(8): 2461-2469. doi:10.13287/j.1001-9332.201708.024

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Canopy reflectance has important meanings in the aspects of accurate interpretation of forest vegetation type and key parameter (leaf area index, chlorophyll content, etc.) retrieval of forest carbon assimilation. In this study, the canopy reflectance time series of three typical subtropical forests (moso bamboo forest, MBF; lei bamboo forest, LBF; evergreen and deciduous broadleaf forest, EDBF) was simulated by coupling PROSPECT5 and 4SAIL models. First, the sensitivity of parameters in PROSPECT5 and 4SAIL model was analyzed to discuss the effects of parameters on the canopy reflectance simulation. Second, unsensitive parameters were optimized using the observed reflectance. Finally, the canopy reflectances of three typical subtropical forests were simulated using PROSPECT5 and 4SAIL models, and compared with MODIS reflectance dataset. The results showed that leaf area index was most sensitive to bands 1, 2, 3, 5 and 7, with the total-order sensitivity indexes of 0.80, 0.83, 0.49, 0.66 and 0.47, respectively. Chlorophyll content was most sensitive to band 4, with the total-order sensitivity index of 0.59. Leaf water content was most sensitive to band 6, with the total-order sensitivity index of 0.54. Leaf structure, carotenoids content, dry matter content, hot parameter and soil factors were not/low sensitive to these bands. Canopy reflectance simulated using the optimized PROSPECT5 and 4SAIL models had the capability in reflecting the real seasonal changes of three typical subtropical forests. The simulated canopy reflectance significantly correlated with MODIS reflectance, with high R² of 0.86, 0.90, 0.93, and low root mean square of 0.09, 0.07, 0.05 for MBF, LBF, and EDBF, respectively. The simulated canopy reflectance solved to some extent the problems of influence on MODIS reflectance products by precipitation and snow in winter, and mixed pixels.

Response of Larix chinensis radial growth to climatic factors based on the Vaganov-Shashkin model

CHEN Lan, LI Shu-heng, HOU Li, SHI A-rong, BAI Hong-ying

2017, 28(8): 2470-2480. doi:10.13287/j.1001-9332.201708.038

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Tree ring width chronologies were established by core samples of Larix chinensis collected from the Herb Temple in southern slope and the Shangban Temple in northern slope of Taibai Mountain, respectively. Based on the Vaganov-Shashkin model, this paper discussed the responses of Qinling Mountains L. chinensis’ radial growth to various climatic factors. The research found that the temperatures of growing season (from April to August), the precipitation in initial stage of growth and in July to August were the main climatic factors limiting the growth of L. chinensis. The higher temperature was favorable for the growth of trees, but precipitation in the early stage of growth inhibited it. L. chinensis from the southern and northern slope of Qinling Mountains showed different responses to precipitation in July to August, in which abundant precipitation promoted the growth of L. chinensis in the northern slope, while inhibiting the growth in the southern slope. Even in the same slope, sampling sites with different altitudes brought discrepant responses of trees’ radial growth to climatic factors. The L. chinensis at higher altitude needed lower growth temperature than that at lower altitude, but the former demanded greater soil moisture than the latter. The start day of growth had a great influence on the radial growth of L. chinensis, however, the end day of growth only affected that on the southern slope.

Effect of fire severity on carbon storage of aboveground vegetation in Great Xing’an Mountains, China

HONG Jiao-jiao, CHEN Hong-wei, QI Shu-yan, LIU Na, XU Jing

2017, 28(8): 2481-2487. doi:10.13287/j.1001-9332.201708.039

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Forest aboveground vegetation (trees, shrub, and grass) was sampled in the Huzhong forest region of the Great Xing’an Mountains under different fire severities. The allometric-equation and biomass-harvesting methods were employed to derive biomasses of tree, shrub, and grass layers, which were subsequently converted to carbon storage. The differences of carbon storage (tree, shrub, and grass layers) under different fire severities were analyzed. Results showed that fire severities significantly affected the aboveground carbon storage. The carbon storage was ranked in the order of unburned>low-severity>moderate-severity>high-severity. At the same fire severity, the forest carbon storage was generally ranked in the order of tree>grass>shrub. At the different fire severities, the carbon storage was ranked in the order of unburned>low-severity>moderate-severity>high-severity. The shrub layer carbon storage was ranked in the order of low-severity>unburned>moderate-severity>high-severity. The grass layer carbon storage was ranked in the order of low-severity>unburned>high-severity>moderate-severity. The fire severities significantly affected carbon storage of tree and grass layers. The effect of fire severities on carbon storage in shrub layer was not significant.

Effects of slope gradient and vegetation coverage on hydrodynamic characteristics of overland flow on silty riparian slope

ZHANG Yi-fan, ZHAO Qing-he, DING Sheng-yan, CAO Zi-hao, LIU Pu, WU Chang-song, BIAN Zi-qi

2017, 28(8): 2488-2498. doi:10.13287/j.1001-9332.201708.006

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Revealing the hydrodynamic characteristics is essentially important for understanding the internal mechanism of slope soil erosion. Through a series of simulated runoff scouring experiments conducted in riparian zones of the lower reaches of Yellow River, this paper studied the hydrodynamic process of soil erosion with overland flow on riparian slopes under four different slope gradients (5°, 10°, 15°, 20°) and three levels of vegetation coverage (0%, 15%, 30%) at the same scouring inflow rate (15 L·min^-1), meanwhile, we analyzed the changes of the hydrodynamic parameters, including the flow shear stress (τ), stream power (ω), and unit flow energy (F), and their responses to slope gradient, vegetation coverage and their interaction effects as well. The results indicated that τ, ω and F showed clear change rules under the effects of slope gradient and vegetation coverage. With fixed slope gradients, τ increased while ω and F decreased with the increase of vegetation coverage. Nonetheless, τ, ω and F all increased with the growth of slope gradient under the same vegetation coverage. The effect of changes in both slope gradient and vegetation coverage on soil erosion was insignificant on the slope less than 10°, while the effect of vegetation coverage on reducing soil erosion rate was obvious on the slope more than 10°. Similarly, the slope soil erosion yield aggravated significantly with the increase of slope gradient under the same vegetation coverage. Moreover, the soil erosion rate showed a good linear relationship with both τ and ω, and they both had critical flow shear stress and threshold stream power throughout the whole soil erosion process. F showed a good logarithmic relationship with soil erosion rate. Based on the double factor variance analysis, the effects of slope gradient and vegetation coverage on τ, ω and F were significant, while their interaction effect was significant only on ω, and insignificant on τ and F.

Distribution simulation of Gentiana rhodantha in Southwest China and assessment of climate change impact

SHEN Tao, ZHANG Ji, SHEN Shi-kang, ZHAO Yan-li, WANG Yuan-zhong

2017, 28(8): 2499-2508. doi:10.13287/j.1001-9332.201708.017

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Based on 230 presence point records and 33 climatic variables, the potential distribution of Gentiana rhodantha during the Mid Holocene (about 6000 years ago), current (1950-2000) and future (2050s and 2070s) was simulated using the MaxEnt model. The main climatic factors affecting Gentiana rhodantha distribution were screened by multivariate statistical analysis and ArcGIS spatial analysis to investigate the sensitivity of different distribution areas to climate change.The areas under the curve indexes (AUC) of training data and test data were 0.942 and 0.849, respectively, which indicated the prediction accuracy was high. Five climatic factors, namely, the monthly average maximum temperature in July, the minimum temperature in June, July and August, and isothermality, showed most contribution to the MaxEnt model (cumulatively 59.9%). Area of suitable habitats retreated first and then expanded with climate change in the future. Up to 2070s, the total area of suitable habitats would decrease by 15.0% under RCP 8.5 compared with the current distribution, but areas of suitable habitats and highly suitable habitats in Yunnan would increase by 32.8% and 32.7%, respectively. The warm and moist climate was suitable for G. rhodantha growth. Lower-altitude regions were more sensitive to climate change, which resulted in the obvious reduction of suitable habitat areas. The areas of suitable habitats in high altitude region, however, would increase with the improvement of temperature and precipitation condition. With the change of global climate, the main distribution area of G. rhodantha would be projected to migrate westward and expand to higher elevations.

Spatial distribution and temporal stability of soil water storage in an oasis-desert ecotone

ZHANG Shuai-pu, SHAO Ming-an, LI Dan-feng

2017, 28(8): 2509-2516. doi:10.13287/j.1001-9332.201708.031

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Understanding soil water dynamics is crucial to water resource management and ecological construction in oasis regions. In this paper, a case study was conducted to examine the spatial-temporal distribution characteristics of soil water using geostatistical analysis and temporal stability analysis in the oasis-desert ecotone of the middle reaches of Heihe River Basin, based on the field monitoring of soil water content throughout the growing season from 2012 to 2014 in a 50 km² area. Results showed that soil water storage for the oasis-desert ecotone on the north shore of the Heihe River was highest in August and lowest in October. The mean soil water storage in the 0-2 m profile was approximately 367 mm. The gradient distribution of soil water storage from the oasis to the desert was not only related to the river channel but also to the land use type. Soil water storage in different land uses followed the order of cropland>forest land>shrub land>desert. On average, soil water storage in the cropland was300% higher than that in the desert. There existed great differences in the temporal stability of soil water storage at different sampling points, and the strength of temporal stability in various land uses was in order of shrub land>desert>cropland>forest land. The seasonal variations of river water had direct effects on soil water within the distance of 3 km. A time-stable transect of soil water was observed between the river-bank oasis and the newly cultivated cropland, which indicated the development and evolution of the oasis ecosystem.

Effects of reclamation on ecosystem carbon emission: Wetland conversion to cropland

HOU Ying, LI Hong, ZHAO Min, XIONG Jun, DAI Sheng-qi, ZHAO Bin, HU Jing, GUO Hai-qiang

2017, 28(8): 2517-2526. doi:10.13287/j.1001-9332.201708.030

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The reclamation of wetlands for agricultural uses affects carbon cycling directly, how-ever, previous studies ignored carbon emissions caused by human activities such as fertilizer production and use of agricultural machinery. To more thoroughly understand the changes in ecosystem carbon emission caused by land reclamations, we used flux observation and life cycle assessment to estimate total ecosystem carbon emission with and without accompanying carbon emissions due to human activities on Chongming Island. The results showed that croplands acted as carbon sink if only carbon fluxes between the ecosystems and atmosphere were considered. However, carbon emission of croplands increased by 10.47 t (CO₂-eq)·hm^-2 compared to wetlands. When carbon emissions caused by human activities were considered, total carbon emission of wetlands and reclaimed croplands respectively were -15.38 and 6.54 t (CO₂-eq)·hm^-2, and the carbon emission due to wetland reclamations increased by 21.92 t (CO₂-eq)·hm^-2, the carbon emissions caused by human activities were 11.45 t (CO₂-eq)·hm^-2. The carbon emissions of agricultural material production and rice cultivation accounted for 84.6% of the total emission in their life cycles, and thus the production and application of fertilizer were largely responsible for the carbon emission. In sum, we need to reassess reclamation effects because it changed carbon sink/source properties at ecosystem and even regional scales. And we should reduce fertilizer use and improve fertilizer use efficiency to achieve low-carbon agriculture.

A spatial sampling strategy for soil carbon flux estimation based on the region division

LI Nan, MO Lu-feng, WANG Guo-ying, ZHOU Jian, GAO Hong-di

2017, 28(8): 2527-2534. doi:10.13287/j.1001-9332.201708.007

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Regional soil carbon flux can not be accurately estimated using traditional sampling methods due to the strong spatial heterogeneity of its spatial distribution, so it is significant to determine appropriate sampling strategies for the estimation of regional soil carbon flux. In this paper, a point-by-point incremental sampling strategy, region division based on point-growing (RDPG), was proposed. According to RDPG, initial sampling points were set firstly, the Delaunay triangulations were constructed using an improved convex hull interpolation algorithm, the discrete degree values at the intersection points of each side perpendicular bisectors of triangles were calculated with interpolation based on known values of sampling points, and then the point with the biggest discrete degree was chosen as a new sampling point. Using the RDPG method, multiple experiments were carried out in some simulation fields with coefficients of variation from 0.42 to 0.59. The results showed that, based on the same experimental conditions,compared with random sampling and uniform sampling strategies, the RDPG strategy could lead to higher accuracy of regional soil carbon flux estimation. The RDPG strategy took the spatial heterogeneity of soil carbon flux into account, which improved the fitting accuracy of regional soil carbon flux.

Quantitative assessment of the impacts of human activities on net primary productivity

WU Yan-yan, WU Zhi-feng, YU Shi-xiao

2017, 28(8): 2535-2544. doi:10.13287/j.1001-9332.201708.019

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Urban expansion and land cover changes driven primarily by human activities have significant influences on urban eco-environment, and together with climatic change jointly affect net primary productivity (NPP). However, quantitative analysis about the impacts of human activities on NPP change isolated from climatic change in the spatiotemporal scale is poorly understood. We took Guangzhou City as study area to estimate the actual NPP (NPP_act) and the potential NPP (NPP_p) from 2001 to 2013 based on Carnegie Ames Stanford Approach (CASA) model and CHIKUGO model, and calculated the loss of NPP due to land use and land cover change (NPP_lulc) from NPP_act and NPP_p. The impact of human activities on NPP in the process of urban sprawl was quantitatively analyzed and assessed by examining a relative contribution index (RCI) based on NPP_p and NPP_lulc. Guangzhou City and its five regions showed a declined trend of NPP_act and an increased trend of NPP_lulc from 2001 to 2013, and significant spatial differences of NPP_act and NPP_lulc were found in all regions. RCI had an increasing trend over 13 years, the smallest value of average RCI occurred in northeastern region (0.31), indicating climatic change was the main cause of NPP change, while the average RCI was higher than 0.5 in the other four regions, indicating that these regions were subjected to severe anthropogenic disturbances and human activities were the dominant factors of NPP reduction. The slopes of RCI change were positive in Guangzhou and its five regions, revealing an increasing human disturbance trend. Northern region had the largest RCI slope of 0.693, suggesting the trend was most obviously in this region.

Evaluation of reactive nitrogen emissions reduction in Beijing-Tianjin-Hebei agglomeration based on ‘N offset’ mechanism and data envelopment analysis

XIAN Chao-fan, WANG Li-yan, LU Fei, ZHENG Hua, OUYANG Zhi-yun

2017, 28(8): 2545-2553. doi:10.13287/j.1001-9332.201708.020

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The rapid development of urbanization has brought the huge ecological pressure and serious environmental pollution, resulting from direct and indirect emissions of anthropogenic reactive nitrogen to atmosphere and hydrosphere during nitrogen consumption. Based on the quantitative analysis of reactive nitrogen emissions by Beijing-Tianjin-Hebei agglomeration, we constructed an evaluation index for annual reactive nitrogen removal efficiency of this region by employing data envelopment analysis. Then we attempted to put forward low-nitrogen development countermeasures based on ‘N offset’ mechanism for the sustainable development. The results showed that the total reactive nitrogen emissions of Beijing-Tianjin-Hebei agglomeration slightly decreased with fluctuation during urbanization in 2004-2014. Hebei Province was the main contributor to nitrogen emission, occupying 79%-84% and 74%-79% of nitrogen loss to atmosphere and hydrosphere. The main sources of emission were agricultural activities, and then turned to industrial activities and residential livelihood. The impacts of urbanization on reactive nitrogen emission intensity of each region were different. The annual emission intensity of this agglomeration was 5.8 t N·km^-2. Beijing City owned the highest of emission reduction efficiency, followed by Hebei Province and Tianjin City. The keys for overall low-nitrogen urbanization were supposed to be the reduction in the emissions intensity of Hebei Province and the improvement in emission reduction efficiency of Tianjin City. The countermeasures toward emission reduction, basing on collaborative ‘N offset’ mechanism, would contribute to the reciprocity among Beijing-Tianjin-Hebei agglomeration in emission reduction during sustainable development.

Variation of ecological water demand and its contributing factors in the southern three outlets of Jingjiang River in the Yangtze River under the condition of hydrologic variation

HE Meng, LYU Dian-qing, LI Jing-bao, DAI Wen, XU Zhi

2017, 28(8): 2554-2562. doi:10.13287/j.1001-9332.201708.029

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Based on the measured original runoff data series at five hydrological stations in the southern three outlets of Jingjiang River in the Yangtze River from 1951 to 2015, variation years of runoff were tested by Mann-Kendall methods. Instream ecological water demands in the southern three outlets of Jingjiang River were calculated through GEV’s maximum flow of probability density. Spatial temporal variation of ecological water demand and its contributing factors were analyzed from the perspective of multi temporal and spatial scales. The results showed that, in the studied periods, the first variation years of runoff were respectively 1990, 1959, 1959, 1972 and 1972 at five hydrological Stations of Xinjiangkou, Shadaoguan, Kangjiagang, Guanjiapu and Mituosi. The monthly average flow sequence before the first variation was used as the hydrological sequence before hydrological variation. Under the conditions of hydrological variation, the ecological water demands each month were respectively 69.63, 26.15, 55.65, 452.65, 2166.44, 4660.83, 10875.66, 9966.49, 7868.38, 4773.60, 1655.01 and 338.49 m³·s^-1 from January to December. The average annual ecological water demands in the five hydrological stations of Xinjiangkou, Shadaoguan, Kangjiagang, Guanjiapu and Mituosi were 901.57, 507.00, 221.30, 1438.03 and 581.62 m³·s^-1 respectively. After the hydrologic variation, the frequency of meeting instream ecological water demand decreased significantly from more than 55% before the hydrologic variation to less than 20% after the hydrologic variation in the three outlets of southern Jingjiang River, and the shortage of ecological water demand became very serious. The main factors affecting the spatial and temporal changes of ecological water demand in the southern three outlets of Jingjiang River in the Yangtze River were human activities of water conservancy projects in the different periods and water consumption in different industries.

Dew condensation time and frequency in the loess hilly region of Ansai County, northern Shaanxi Province, China

WANG Hao, JIA Zhi-feng, LU Yu-dong, HE Zi-li, WANG You-ke, CHEN Yun-ming, WANG Zhi

2017, 28(8): 2563-2568. doi:10.13287/j.1001-9332.201708.015

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Dew condensation time and frequency are basic parameters for exploring the vapor phase of water resources. According to an in-situ monitoring of near-surface dew occurrence between 2015 and 2016 in a typical loess hilly region of Ansai County, Shaanxi Province, the dew condensation time, frequency and their atmospheric influencing factors were analyzed. Results showed that the dew condensation time was long and occurred in cyclic patterns. Over the daily cycle, dew manifested a typical “night-time show and day-time no-show” pattern, and it mainly occurred between 21: 00 and 8: 00 while the most frequently condensed dew period was between 4:00 and 6:00. Over the seasonal cycle, summer and fall had the higher frequency, whereas spring and winter had the lower frequency. Over the annual cycle, the most frequent dew period was from June to November. Compared to rainfall, dewfall had characteristics of higher frequency and stronger stability. A variety of substrate and meteorological factors contributed to the formation of dew, e.g. dew occurred more frequently when the atmospheric relative humidity was greater than 80%, air temperature-dew point difference was between 1 and 3 ℃, and wind speed was between 0 and 1 m·s^-1. In Ansai, wind directions ranging among 120°-150° and 240°-300° were more favorable to dew condensation.

GIS-based risk assessment of the impact of continuous rain in autumn on agricultural production: A case study of the basin area in Sichuan Province, China

ZHANG Han, ZHENG Hao, WANG Ming-tian, YOU Chao

2017, 28(8): 2569-2576. doi:10.13287/j.1001-9332.201708.027

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In order to explore the impact of continuous rain in autumn on agricultural production in the basin area of Sichuan Province, we established a general climate risk evaluation model based on the data of daily precipitation, sunshine hours, hydrology, topography, and crop acreage of 102 meteorological stations from 1961 to 2014. This model analyzed the data from the angles of climate disaster components, regional environmental conditions and the features of hazard bearing body to produce an index that reflected the level of risk. Using the index, we divided the basin area into five risk zones. The results indicated that the areas with the highest risk of continuous rain in autumn were the flat and hilly areas in the southwest, the shallow hilly areas in the south, the hilly areas in the northeast, as well as the regions along Jialing River and Qujiang River. Therefore, it is necessary to strengthen the forecast and defense countermeasures of autumn continuous rain to these regions. The edges of the basin belonged to low risk zones due to their mountainous topography and limited availability of arable lands, and the damage of continuous rain was not heavy. The risk levels for the rest of basin ranged from relatively low to relatively high.

Carbon footprint of crop production in China from 1993 to 2013 and its spatial distribution

LIU Yu-feng, YUAN Zhi-hua, GUO Ling-xia, SUN Bo, KONG Wei, TANG Shu-hui

2017, 28(8): 2577-2587. doi:10.13287/j.1001-9332.201708.004

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Based on China’s agricultural statistical data in 1993-2013, using methods such as the Life Cycle Assessment, the Gravity Center Model and GIS, this paper analyzed the temporal variation of carbon emission and carbon footprint in crop production, the orbit of carbon footprint center-of-gravity, the spatial variations of carbon footprint and carbon emission and the main influence factors of carbon emission. The results showed that, during the study period, carbon emission of China’s crop production (GHGe), carbon footprint per unit of sown area (CFs) and carbon footprint per unit of cultivated area (CFc) increased significantly, while carbon footprint per unit of yield (CFy) and carbon footprint per unit of production value (CFv) decreased significantly. The CFs center-of-gravity had stayed in Henan, and moved towards southwest gradually, the CFc center-of-gravity located in Hubei or Henan and moved towards northwest, the CFy center-of-gravity situated in Shaanxi or Henan, and transferred towards southeast integrally, the CFv center-of-gravity stayed in Henan and shifted towards southwest. GHGe and carbon footprint demonstrated remarkable discrepancy in provincial region. The GHGe tended to be low in the north and south, while high in central China, the CFs in central China was lower than that in east and west China, the regions with high CFc were mainly concentrated in the central and eastern coastal provinces, the CFy trend was high-low-high from the northwest to the southeast, while the CFv went down from the northwest to the southeast. The ratio of corp carbon footprint investment during agricultural production process was highest in chemical fertilizer, in which nitrogen fertilizer and compound fertilizer proportion were bigger. Through analyzing the correlation degree between GHGe and various influencing factors, results showed the chemical fertilizer especially phosphate and nitrogen fertilizer, irrigation and cropland N₂O emissions were the key factors to GHGe’s obvious increase, accordingly, suggestions on the low-carbon agriculture development were proposed.

Effects of isotonic NaCl and drought stress on photosynthetic characteristics and chloroplast ultrastructure of tomato seedlings

YANG Feng-jun, LI Tian-lai, ZANG Zhong-jing, WU Xia

2017, 28(8): 2588-2596. doi:10.13287/j.1001-9332.201708.041

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In order to analyze the effects of isotonic salt stress and water stress on the photosynthetic characteristics of tomato leaves, four kinds of genotype tomatoes with different salt tolerance (small fruit type croton agate, wild currant tomato, large fruit type Jintian powder crown, and supernatant 402) were selected to conduct water and isotonic tolerance experiments under 140 mmol·L^-1 NaCl and 15% PEG6000 simulating condition. The results showed that, 12 days after treatment, significant decreases in chlorophyll content (chlorophyll a, chlorophyll b, and total chlorophyll), photosynthetic rate, stomatal conductance, intercellular CO₂ concentration, and transpiration efficiency were observed, and the value of stomatal limitation was increased. Stomatal factors might reduce the decline in photosynthesis under the two kinds of stresses. The damage of the photosynthetic system under isotonic salt stress was greater than that under water stress, because water stress resulted in osmotic stress and ion damage. Among the genotype tomatoes, the salt-tolerant Lantau red agate exhibited high photosynthetic characteristics, and Jindian powder crown had the lowest photosynthetic efficiency. For the ultrastructure of chloroplasts, both stress treatments increased the stomatal density of tomato leaves, but decreased the numbers of open stomata. The length of chloroplasts was increased, the width was decreased, and the length/width ratios of chloroplasts were increased. In addition, number of chloroplast grana was decreased and that of osmiophilic globules was increased. The effect of salt stress on the chloroplast structure was greater than that of water treatment. The change in stomata of salt-tolerant currant tomato was less than that of salt-sensitive cultivar.

Model construction of potassium accumulation and utilization in tea seedling

GONG Xue-jiao, LUO Fan, TANG Xiao-bo, WANG Xiao-ping, LI Chun-hua, WANG Ying-chun, WANG Yun, DU Xiao

2017, 28(8): 2597-2604. doi:10.13287/j.1001-9332.201708.016

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A hydroponic experiment was conducted and regression mathematical models were established for quantitative study of the relation between potassium content of tea seedling plant and potassium concentration in nutrient solution, and the relation between potassium content of shoot and that of tea plant. In addition, the effects of potassium on promoting the synthesis of chlorophyll and photosynthesis were analyzed. The results showed that the potassium content of whole plant, shoot, stem and root, which increased first and then decreased with the increase of potassium concentration in culture medium, reached the maximum in the potassium concentration range of 6.82-8.65 mmol·L^-1, and accorded with the normal distribution curve. The potassium content of mature leaf increased linearly and did not decrease in the test period. The shoot, mature leaf and root, with maximum potassium contents of 20.04, 16.02 and 12.03 mg·g^-1, respectively, contributed greatly to the whole plant potassium content. The maximum potassium content of the whole plant was 10.53 mg·g^-1, and the maximum potassium content of different parts of stem was 8.08-8.27 mg·g^-1. The shoot achieved higher maximum efficiency of content of potassium (1.22) under a lower potassium concentration (3.65 mmol·L^-1) condition than other organs, indicating a stronger ability to accumulate potassium. The shoot potassium content was linear with that of mature leaf and whole plant, while had a first-order exponential relation with that of stem. Potassium accumulation efficiency of root began to fall when potassium concentration was above 5.13 mmol·L^-1, causing the decreased supply of potassium to the shoot. Net photosynthetic rate (P_n) and chlorophyll content variation with the increase of potassium content showed a Boltzman curve, and the optimal potassium content (10.03-10.83 mg·g^-1 in mature leaf and 17.72-19.11 mg·g^-1 in shoot) and potassium concentration in culture medium(4.69-5.96 mmol·L^-1) were found to promote the chlorophyll synthesis and P_n.

Comparison of ZTCM and TCIA methods for evaluating the use value of tourism resources: Taking Beijing Olympic Forest Park as an example

DONG Tian, ZHENG Hua, XIAO Yi, OUYANG Zhi-yun

2017, 28(8): 2605-2610. doi:10.13287/j.1001-9332.201708.034

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The zonal travel cost model (ZTCM) and travel cost interval analysis (TCIA) are two commonly used tourism resources valuation methods. However, the two models may lead to different results because of different starting points. Comparing the evaluation results of the two methods is very important for the accurate evaluation of the tourism resource use value. In this study, Beijing Olympic Forest Park was used to study the use value of this scenic spot by using the questionnaire and ZTCM and TCIA. The results showed that the landscape use value was 16.236 and 3.732 billion yuan by using ZTCM and TCIA, respectively. The fitness of the additional cost and tourist number by TCIA was higher than that by ZTCM. TCIA could effectively improve the ZTCM assumption in the same departure place for the sample of travel expenses that varied greatly at the same place of departure. The results were more realistic and more suitable for the accurate evaluation of the use value of tourism resources evaluation.

Landscape pattern change and its driving mechanism in Yihe River basin, China

REN Jia-yan, LIU Hui-min, DING Sheng-yan, WANG Mei-na, BIAN Zi-qi

2017, 28(8): 2611-2620. doi:10.13287/j.1001-9332.201708.023

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On the basis of land cover data in 1987, 2000, 2008 and 2013, meteorological data and the social-economic data in the same period of Yihe River basin, the landscape pattern change and its driving mechanism in this area were analyzed at different spatial-temporal scales by applying the theory of landscape ecology and using tools such as ArcGIS 10.2, Fragstats 4.2 and SPSS 17.0. Results showed that between 1987 and 2013, the spatial structure of landscape in the study area was changed obviously. The areas of forest land, grassland, reservoirs and construction land increased, while the areas of cultivated land and canals had a trend of “decrease-increase-decrease”. From 1987 to 2008, cultivated land was mainly transformed to construction land, and from 2008 to 2013, the transformation among cultivated land, forest land and grassland was significant. The variation of landscape spatial pattern was concentrated in the valley plains and hilly areas with elevations under 550 m. But as the disturbance of human activities were much stronger, landscape patterns in mountain areas began to change. The analysis of landscape pattern index showed that cultivated land and forest land had the greatest largest patch index (LPI) and cohesion index (COHESION). Between 1987 and 2013, the number of patches (NP) in Yihe River basin increased rapidly. The landscape division index (DIVISION), Shannon’s evenness index (SHEI) and Shannon’s diversity index (SHDI) all showed the trend of “increase-slight decrease-increase”, which indicated that the landscape pattern tended to be unstable, and landscape heterogeneity increased. Social-economic development and the population growth were main driving factors of the transformation of cultivated land and unused land into construction land. The rising temperature and evapotranspiration directly caused the change of water area in this river basin, and the policy was the fundamental reason for the changes in the structures of forest land and grassland.

Coupling relationship of landscape pattern and urban heat island effect in Xi’an, China

WANG Yao-bin, ZHAO Yong-hualt;sup>*</sup>, HAN Lei, AO Yong, CAI Jian

2017, 28(8): 2621-2628. doi:10.13287/j.1001-9332.201708.022

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To examine the influence of landscape pattern on the urban heat island effect for Xi’an, China, landscape classification and temperature inversion were performed using 2000, 2006, and 2015 remote sensing datasets, and the regression model was established. The results showed that correlations between landscape indices and temperature differed according to spatial scale. On the landscape scale, the landscape shape index (LSI), landscape division index (DIVISION), and Shannon’s diversity index (SHDI) were significantly correlated with temperature. On the class scale, CA₁, PD₁, LSI₁, AI₁, LPI₂, AI₂, CA₃, DIVISION₃, LPI₃, AI₄(where “1” indicated built-up land, “2” indicated cropland, “3” indicated forestland, and “4” indicated grassland; where CA referred to class area, PD referred to patch density, LSI referred to landscape shape index, AI referred to aggregation index, DIVISION referred to landscape division index, and LPI referred to largest patch index) were significantly correlated with temperature. The landscape pattern was the main factor affecting the urban heat island, and there was a strong response for this effect. Lots of the landscape indices could represent surface temperature, and modifying the configuration of landscapes could have significant long-term effect on reducing the urban heat island effect. The prediction of multiple linear regression models established on different scales showed that the heat island effect was lower in 2030 than in 2015, but the decrease was not significant, and the effect was still stronger than that in 2006. The heat island effect first spread outward from the main city by point-to-area expansion, then it was weakened in the main city and increased in the surrounding area (counties).

Impact of landscape pattern change on ecosystem service value of Xi’an City, China

ZOU Yue, ZHOU Zhong-xue

2017, 28(8): 2629-2639. doi:10.13287/j.1001-9332.201708.009

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It is very important to study the impact of landscape pattern change on ecosystem service value in rapid urbanization area, for the regulation and control of urban spatial pattern, the construction of healthy and stable urban ecosystem, the optimal utilization of regional land resources, the conservation of ecological environment and the regional sustainable development. Based on the interpretation data of remote sensing imageries (1999, 2006 and 2015) and the socio-economic data of Xi’an City, using the theory of landscape ecology and ecosystem services, this paper investigated the characteristics of landscape pattern and the temporal and spatial variation of ecosystem service value under the influence of urbanization in Xi’an, and then quantitatively analyzed the effects of landscape pattern change on ecosystem service value. The results showed that, with the acceleration of urbanization, the landscape in Xi’an experienced great changes in recent decades, with the area of built-up land and orchard increased, the area of arable land, woodland and water body reduced, and the landscape became more fragmented, diversified and irregular. From 1999 to 2015, the total value of ecosystem services in Xi’an was reduced by 19.03 billion yuan, in which the ecological service values provided by arable land, woodland and water body decreased, and that by orchard landscape increased. The contribution of climate regulation to the total value of ecosystem services was the largest, the reduction of gas regulating value was the largest, and the value of water conservation reduction rate was the largest. In Xi’an City, ecosystem service value was lower in the central urban area and higher in the southern mountainous area. The total value of ecological service from 1999 to 2015 declined, and the range of low-value area gradually expanded from the central urban area to surrounding counties. The change of landscape pattern could have important influence on the structure, function and process of regional ecosystem. The expansion and spread of the urban landscape as well as the extension of traffic network made the landscape more fragmented. The decrease of woodland, arable land and water body which provided higher ecological service value could lead to the reduction of value in regional ecosystem services.

Spatial characteristics and evolution of rural settlement landscape based on fractal theory: A case study of Xiamen, China

LIANG Fa-chao, LIU Shi-yuan, LIU Li-ming

2017, 28(8): 2640-2648. doi:10.13287/j.1001-9332.201708.037

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The characteristics of rural settlement landscape are composed of spatial structure and morphology, which are also the basis for optimizing rural land use patterns. Using the fractal theory, this paper quantitatively analyzed the characteristics and evolution of spatial structure rural settlement landscape in Xiamen from the city and town scales, and proposed corresponding optimization counter measures. The results showed that the fractal of spatial structure and pattern of rural settlement landscape was significant in Xiamen. At the city level, aggregation dimension, accessibility of traffic network and spatial dimension increased overtime, while the spatial correlation dimension showed an opposite trend. Overall, the spatial structure of rural settlement landscape showed a multi-center-aggregation distribution, and the accessibility of traffic network got better. Meanwhile, the self-organization of spatial structure constantly optimized, and the spatial form of rural settlement landscape tended to more complicated in terms of extension trend. At the town level, there were significant differences in spatial characteristics of rural settlement landscapes. In some towns, several problems such as loosing spatial structure, poor accessibility of traffic network were still unsolved. In the foreseeable future, the construction of transportation infrastructure and central villages needed to be actively pushed. Besides, the correlation between various elements within the rural settlements also need to be enhanced. The results could provide theoretical and technical support for the optimization of rural settlement space and scientific complication of land use planning.

Landscape dynamic and conservation efficiency in Ar Horqin National Nature Reserve, Inner Mongolia, China

GUO Zi-liang, CUI Guo-fa, WANG Xiao-ping, NA La-su, ZHENG Yao-min, ZHANG Man-yin, CUI Li-juan

2017, 28(8): 2649-2656. doi:10.13287/j.1001-9332.201708.028

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To assess quickly the conservation efficacy of nature reserve is of great significance to make scientific management decisions. In this paper, the remote sensing image was first interpreted, in order to accomplish the landscape classification and analyze the landscape dynamic of Ar Horqin Nature Reserve, Inner Mongolia. And then we assessed the conservation efficacy of this nature reserve during the 2004-2014 by using the quality index of protected landscape, interference index of anthropogenic landscape and conservation efficacy index, etc. The results showed that the proportion of natural landscapes in Ar Horqin Nature Reserve, Inner Mongolia increased from 92.2% to 92.8% during 2004-2014, with a significant increase in areas of natural grassland and shrub land, while the areas of lake and river reduced quickly. Meanwhile, the landscape pattern had significantly changed in this nature reserve. The proportions of areas transformed to and from other landscape types were particularly high, and the landscape transformation index was 0.33. Moreover, the protected landscapes in the nature reserve and its various function zones increased obviously in area and proportion, with the quality index of protected landscapes of this nature reserve increased from 24.37 in 2004 to 25.36 in 2014, indicating the quality of protected landscape improved. Nonetheless, each function zone had different degrees of artificial interference in the nature reserve, and the artificial interfered landscapes increased distinctively. The interference index of anthropogenic landscapes was -0.79 and -0.96 in 2004 and 2014 respectively, showing that artificial disturbance intensity was strengthened. On the whole, it was found that the conservation efficacy index of Ar Horqin Nature Reserve, Inner Mongolia was 3.5% during the study period, which achieved a “very good” landscape conservation efficacy, and wildlife habitat tended to be better.

Ecological function zoning in Inner Mongolia Autonomous Region based on ecosystem service bundles

LI Hui-lei, PENG Jian, HU Yi-na, WU Wen-huan

2017, 28(8): 2657-2666. doi:10.13287/j.1001-9332.201708.036

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Ecological function zoning is an important part of ecosystem management and can maintain the ecological sustainability. However, the existent frameworks of ecological function zoning are multiple and complicated, and the understanding of the relationship between multiple ecosystem services is not deep enough. The ecosystem service bundles can identify the interaction among multiple ecosystem services and divide the region according to characteristics of the bundles, which can carry out the management of social-ecological system. In this paper, taking the Inner Mongolia Autonomous Region as an example, we quantitatively evaluated the provisioning service, regulating service and supporting service, and used the self-organization feature map (SOFM) to get the ecosystem service bundles at the county level,with the ecological function zoning on this basis. The results showed that the distribution of ecosystem services appeared a decreasing trend from northeast to southwest. There were tradeoffs between provisioning and regulating services, and synergies between supporting and regulating services. According to the bundles results, we divided the Inner Mongolia Autonomous Region into 4 ecological function zones: ecological fragile area in western desert, soil and water conservation area in central grassland, livestock surplus area in eastern grassland, and ecological balance area in eastern forest land. Based on the concept of ecosystem service bundles, this paper analyzed the tradeoffs and synergies among multiple ecosystem services in the study area, which provided a new perspective and method for ecological function zoning.

Quantitative assessment of ecological quality in Beijing-Tianjin-Hebei urban megaregion, China

WANG Jing, ZHOU Wei-qi, XU Kai-peng, YAN Jing-li, LI Wei-feng, HAN Li-jian

2017, 28(8): 2667-2676. doi:10.13287/j.1001-9332.201708.008

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The ecological quality symbolizes the capacity of sustainable development of regional economy and society, as well as the degree of stability and coordination between social production and human settlement environment. Therefore, how to quantitatively assess ecological quality and its change, as well as coordinate the relation between the ecological quality and urbanization, is becoming a hotspot of urban ecology. The Beijing-Tianjin-Hebei (BTH) urban megaregion, where urbanization developed rapidly and environmental problems became increasingly evident, was chosen as the study area. Then we calculated the ecological parameters including the vegetation fraction, biomass, and the percent cover of built-up land based on remote sensing data, and combined with vegetation fragmentation index, to develop a comprehensive index model of ecological quality based on RS indicators by using principal component analysis. The ecological quality and its dynamics in the BTH urban megaregion from 2000 to 2010 were quantitatively evaluated. The results showed that the ecological model constructed in this paper could be used to evaluate the ecological quality and change of city and region objectively and comprehensively. The index of ecological quality in BTH increased from 2.38 in 2000 to 2.84 in 2010, with a growth rate of 19.3%. The growth rate of2000-2005 (12.2%) was higher than that of 2006-2010 (7.2%). Spatially, high values of the index were distributed in the north of the megaregion, while low values in the west and southeast. Ecological quality and its change varied greatly by cities. The ecological quality of Chengde was better than the other cities significantly, followed by Beijing, Qinhuangdao and Baoding, whereas Tianjin had the worst ecological quality. The ecological quality in Chengde, Beijing, Qinhuangdao and Baoding were higher than the average level of the entire BTH megaregion, while Langfang, Tianjin and Cangzhou were lower than the average level. Except for Tangshan, the ecological quality in all other cities was improved from 2000 to 2010. The ecological quality indices of Cangzhou and Hengshui were improved significantly, with growth rates of 520.5% and 171.8%, respectively.

Multidimensional and comprehensive poverty measurement of poverty-stricken counties from the perspective of ecological poverty

WANG Yan-hui, QIAN Le-yi, CHEN Ye-feng, HU Zhuo-wei

2017, 28(8): 2677-2686. doi:10.13287/j.1001-9332.201708.003

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As an important implementation unit of national poverty alleviation and development strategies, identifying each poverty-stricken county’s poverty degree and poverty contributing factors is the precondition and guarantee of implementing national precise poverty reduction strategies. To response to it, from the perspective of ecological poverty, this paper brought up a county-level multidimensional poverty measurement index system, which took into considerations of the sustainable development among natural environment, economy and society, and then constructed a PI-MVM multidimensional poverty measurement model to explore the destitute areas and poverty-stricken counties’ poverty degrees and poverty contributing factors, as well as their spatial distributions. The case test from 6 destitute areas and 249 counties shows that the poverty degrees of the destitute areas increase from north to south, and the counties’ poverty degrees present a trend of “increasing from north to south and from east to west”. There exists a high-high aggregation distribution both in west of Wumeng and northwest of Qinba areas. Natural environment factors play an important role in both south central of Qinba and Wumeng area, where the poverty degree is higher. Those counties with general poverty contributing type have the most cases, while those counties with dominant po-verty contributing type are gathered in smaller poverty-degree areas. The contribution of economic factors to poverty alleviation decreases gradually. On the contrary, the influences of natural environment and society factors increase obviously. This result could help policy-makers to grasp the whole poverty characteristic of poverty-stricken counties, as well as provide technical support for auxiliary decision making.

Green development regionalization in Jiangxi Province, China

ZHU Mei-qing, SHI Wen-jiao, HUANG Hong-sheng

2017, 28(8): 2687-2696. doi:10.13287/j.1001-9332.201708.001

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The research of green development regionalization is the premise and basis of the adaptation to the new situations of “Green Development”, “Demonstrative Pilot Zone of Ecological Civilization” and “Experiment Zone of Ecological Civilization”, which should be transformed from the ecological management model of emergency rescue (mountain governance, river governance, lake governance, and poor governance) to the sustainable development model of reducing pressure and increasing efficiency (rich in mountain, rich in water, rich in people, and strengthening in ecology) in Jiangxi Province. Previous studies of regionalization emphasized ecological protection but neglected green development. Based on the spatial data including terrain, geomorphology, ecology, agriculture, forestry, grassland, wetland, economy and tourism in Jiangxi Province, our research set up an index system including 44 indices, which combined qualitative and quantitative, ecological and economic as well as comprehensive and important factors. Based on this index system, the development condition and direction for each research unit was evaluated. After these evaluations, we divided Jiangxi Province into 4 first-level types, 17 second-level types and 51 third-level types. This research took green development as the goal, the county’s ecological resources and the deve-lopment advantages as the basis, the green development approach of each unit as a breakthrough for the first time. The results of the regionalization were helpful to define the direction of the green development for each county, to guide the optimum utilization of resources and the rational distribution of industries, and to provide scientific basis for the ecological environment protection and sustainable development in Jiangxi Province.

Spatial distribution characteristics of urban potential population in Shenyang City based on GIS and RS

ZHAO Dong, LI Jun-ying, YAN Hong-wei, YIN Hong-yan, YANG Jing-hui, FU Yao-dong, LI Jin-xin

2017, 28(8): 2697-2704. doi:10.13287/j.1001-9332.201708.018

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The urban residential building area was measured by shadow length method based on information extracted from the QuickBird remote sensing images, and the spatial distribution characteristics of the city population were analyzed according to the social and economic statistics. The distribution of the population in different districts within the Third-Ring Road of Shenyang was uneven in 2015, and the spatial distribution of potential population within the area presented a typical circle structure. The district’s potential population decreased in sequence of Tiexi, Shenhe, Huanggu, Yuhong, Heping, Dadong, and Dongling, and the district’s potential population density decreased in sequence of Tiexi, Heping, Shenhe, Huanggu, Yuhong, Dadong, and Dongling. The potential population density was higher in the west than in the east, and higher in the south than in the north. The spatial distribution of residential buildings and population were closely related to the natural condition, economy and infrastructure. The construction of infrastructure in both Tiexi District and city center should be strengthened in the future urban plan, and increase the green space appropria-tely. Furthermore, the residential land in the south should be increased, and the residential population should be regulated to avoid greater environmental pressure.

Potential habitat distribution for Cervids based on different forest management area scena-rios

WU Wen, LI Yue-hui, HU Yuan-man, CHEN Long, XIONG Zai-ping

2017, 28(8): 2705-2713. doi:10.13287/j.1001-9332.201708.021

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It is theoretically and practically important to explore suitable habitat distribution of the Cervids for relieving the confliction between small-scale human management and large-scale habitat conservation in a human-disturbed forest landscape. Using the present locations of Cervids (n=196) observed in field investigations in 2013, 2014 and 2015, we grouped 17 environmental predictor variables into four predictor classes (terrain, habitat type, vegetation feature, and interference) and used those variables to build a maximum entropy (MaxEnt) model. Then, we estimated the potential habitat of red deer and roe deer, and determined the contribution of environmental factors to the distribution characteristics in four forest management area scenarios by this model. Results showed that models validation had high average accuracy and the stability appeared satisfactory. The potential suitable habitat for Cervids was located mostly in the eastern region. The environmental factors significantly affecting habitat suitability of red deer and roe deer were similar in different scenarios, and they were distance to farmland, distance to settlement, distance to river, distance to management area and elevation. Distance to management area factor was found to have a certain extent effect on habitat suitability with contribution probability from 4% to 6%. The distance to management area was about 1200-1300 m both for red deer and roe deer. In none management scenario, the suitable habitat was widely distributed in large area. With the increase of management area, the suitable habitat decreased. When the management area expanded to the twofold or threefold of the current one, Cervids habitat shrank greatly.

Simulation and application of water quality model in a polluted river under eco-restoration engineering scheme

XU Bin, YANG Yue-suo, WANG Yong , ZHANG Gang, FAN Wei, LU Ying, GAO Cui-ping

2017, 28(8): 2714-2722. doi:10.13287/j.1001-9332.201708.040

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Ecological engineering is an important approach for river quality restoration; whilst mathematical models can effectively simulate the water treatment and eco-restoration efficiency. According to the actual data, a hydrological model was constructed and verified via application of the WASP water quality model, which was then used for simulation and evaluation of the river’s main chemical parameters. It was also employed to study the ecological effect on river water quality improvement by constructed wetlands and aerated re-oxygenation. The results showed that the WASP water quality simulation was in good agreement with the water quality measurement, and different ecological restoration scenarios could be predicted and analyzed. Reasonable emission reduction, constructed wetlands and aerated re-oxygenation could reduce the pollutant concentration in the river water, and effectively improve the water quality. Incorporation of the aerated re-oxygenation device into the constructed wetland system would further enhance the river water ecological restoration efficiency. Taking the constructed wetland project with aeration of Yitong River in Jilin Province as an example, the ecological restoration efficiency was analyzed. The results showed that the removal effect of pollutants was the best in summer, and the possible reason was that the air temperature was higher in summer leading to stronger microbial activity in water. This study was of significance to the design and operation of ecological restoration engineering for the polluted river environment.

Progress of quantitative analysis of ecosystem service flow

LIU Hui-min, LIU Lyu-yi, REN Jia-yan, BIAN Zi-qi, DING Sheng-yan

2017, 28(8): 2723-2730. doi:10.13287/j.1001-9332.201708.025

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Ecosystem services flow plays an important role in the generation, delivery, transformation and maintenance of ecosystem services. It can establish spatial connections between the supply and demands of ecosystem services. The quantification of ecosystem services flow is conductive to assess ecosystem services accurately, and has great significance on the conservation and management of ecosystems, and effective development of ecological compensation. This paper analyzed the theoretical basis of ecosystem services flow, summarized definitions of ecosystem services flow that proposed by different scholars to analyze their emphases on quantifying services flow, and then classifying ecosystem services flow. Key factors that might influence the quantification of ecosystem services flow were discussed to analyze the interactions among supply, fluxion and demands of ecosystem services flow. The specific process of quantification of ecosystem services flow was proposed, and each step was introduced in detail.

Research progress on the mechanism of ecosystem services generation

LIU Lyu-yi, LIU Hui-min, REN Jia-yan, BIAN Zi-qi, DING Sheng-yan

2017, 28(8): 2731-2738. doi:10.13287/j.1001-9332.201708.010

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In recent years, the generation of ecosystem services (ES) and its underlying mechanism has become one of the hot topics in ecology. After Millennium Ecosystem Assessment (MA) held in 2005, pertinent studies of ES, such as the classification, valuation, trade-offs and synergy, delivery and flow of ES increased rapidly. The research on ES has entered the new phase. However, to know ES better and explore much deeper, it is essential to disentangle the mechanism of ES ge-neration. Existing literatures indicate that there is still no appropriate research paradigm in this area. In this article, previous works both at home and abroad were reviewed. Then, literatures in recent ten years that directly related to the mechanism of ES generation were summarized. From two points of view, which were intrinsic and extrinsic factors, the roles that biodiversity and human-involved activities playing in the process of ES generation were emphatically analyzed, and the proposed research in the future was prospected.

Progress on the studies of ecosystem accounting

SHI Wei, LI Jin-chang

2017, 28(8): 2739-2748. doi:10.13287/j.1001-9332.201708.012

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Ecosystem accounting aims at integrating the value and amount of ecosystem services and ecosystem assets into the system of national accounts and integrating ecosystem protection targets into social and economic decision-making, in order to realize the coordinated development of ecologi-cal environment and economic society. This paper reviewed the fundamental problems of ecosystem accounting, designing of ecosystem accounts, and valuation method. First, through the interpretation of ecosystem services and its classification, this paper illustrated the process of ecosystem based on the perspective of final ecosystem service, and extended the production boundary of System of National Accounts (SNA). Second, this paper designed ecosystem asset account, ecosystem production account, and supply-use account, and then compared the different impacts of the production scale extension methods on the production accounts. Third, this paper distinguished the valuation method based on exchange value from the one based on welfare economic theory, and pointed out that accounting methods based on the exchange value were consistent with SNA. Finally, it summarized the deficiencies in current researches, and prospects for future study.

Research progress on soil erodibility

WEI Hui, ZHAO Wen-wu, WANG Jing

2017, 28(8): 2749-2759. doi:10.13287/j.1001-9332.201708.011

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Soil erodibility is the soil susceptibility to resist external forcing of erosion and transportation. It is the necessary factor for establishing soil loss equation and soil erosion model. Research on soil erodibility is one of the keys to understand the mechanism of soil erosion. Based on previous research achievement, this paper reviewed the progress of the soil erodibility research. The relevant concepts of soil erodibility include soil anti-scouribility and K-factor, etc. There are different types of soil erodibility, such as soil erodibility of water erosion, soil erodibility of wind erosion, soil erodibility of gravity erosion and soil erodibility of freezing thaw erosion. The evaluation index system of soil erodibility can be divided into two types. One is the evaluation index system based on the soil intrinsic properties and another is the evaluation index system based on external forcing. There are five types of methods that are commonly used to assess soil erodibility, including the measurement of soil physical and chemical properties, the instrumental measurement, the area measurement, the mathematical model and graphic method and the hydrodynamic model solving method. Soil erodibility has obvious spatial-temporal variation characteristics. Its influencing factors include soil property, climate, vegetation, terrain, land use, etc. In the future research of soil erodibility, more attention should be paid to the definition of soil erodibility, the standardization and unification of evaluation index system, the regional applicability of soil erodibility estimation models and the dynamic mechanism of soil erodibility.

Modification and application of the DNDC model in China

XIE Hai-kuan, JIANG Yu-qian, LI Hu, ZHANG Jing, CHANG Nai-jie, WANG Li-gang

2017, 28(8): 2760-2770. doi:10.13287/j.1001-9332.201708.033

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The DNDC model is one of the most successful biogeochemical models, which can be applied to a specific country or regional environment condition. Through continuous improvement and modification, scientists in China have developed a unique version of the model adapting to agricultural ecosystem of China, such as modifying the default parameters of soil water and nitrogen transport processes, introducing the soil conservation service curve and modifying universal soil loss equation to control and simulate the surface runoff, establishing the parameterized module of the film mulching management practice, and adding the manure management sub-model into the original version. These changes could not only increase the capability of the model to simulate the soil water and nitrogen migration, nitrogen leaching and surface runoff, but also expand the application range in different agricultural ecosystems within various management modes. The improved model had been tested against a large number of observations on soil organic carbon, greenhouse gas emissions and nitrogen balance in typical agricultural ecosystems, and then applied on both site and regional scales in China. Furthermore, this paper discussed some problems of the DNDC model, such as inaccuracy of the simulation results, difficulties in the model parameter correction, and inadequate model module. Finally, the developing direction of the model was proposed, so as to enhance the applicability of the model, and more importantly, to serve agricultural policy making in China.

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