Northeast Institute of Geography and Agroecology, Chinese Academy Of Sciences
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Snail (Mollusca: Gastropoda) assemblages as indicators of ecological condition in freshwater wetlands of Northeastern China
No full textThe utility of aquatic macroinvertebrates as indicators of the ecological conditions has long been established in rivers and streams. However, useful invertebrate indicators of wetland conditions remain more poorly developed probably because wetland macroinvertebrates have many attributes that reduce their ability to reflect wetland environmental quality. Snails, however, possess several attributes that should make them useful as potential environmental indicators. In this study, we sampled snail assemblages in 16 wetlands across a range of conditions, from relatively pristine "best available" reference sites to obviously human-impacted sites in Northeastern China's Sanjiang Plain. We aimed to investigate the utility of snail taxa for indicating environmental variation across these wetland habitats. Results showed that study wetlands divided into three major groups using multivariate analyses: the five wetlands provided the most protection and having the least impacts grouped as apparent "references", and ten other wetlands in obviously developed areas separated into two other groups of wetlands. Overall snail abundance was higher in the reference wetlands than the impacted wetlands. Seven of the snail species were indicators of specific wetland types. Five pulmonate species including Segmentina nitida, Segmentina hemisphaerula, and Planorbis corneus, Aplexa hypnorum (Physidae), and Galba pervia (Lymnaeidae) were indicators of reference wetlands. Non-pulmonate Bithynia ussuriensis (Bithyniidae) and Valvata sibirica (Valvatidae) were indicators of one of the categories of impacted wetlands. In NE China, snail assemblages and certain indicator species may provide a robust and rapid indicator of environmental impacts on wetlands. Because snails are distributed widely and are generally easy to sample and identify, this overall approach should have applicability in the many wetlands worldwide where diverse snail assemblages naturally occur. (C) 2016 Elsevier Ltd. All rights reserved
Characterization of Pb2+ biosorption by psychrotrophic strain Pseudomonas sp I3 isolated from permafrost soil of Mohe wetland in Northeast China
No full textDue to the long and severe winter in Northeast China, wastewater containing lead (Pb) is treated inefficiently, resulting in irregular disposal. In order to solve this problem, a Pb-resistant psychrotrophic bacterium, Pseudomonas sp. I3, was isolated from permafrost soil of Mohe wetland and served as biosorbent for Pb2+ removal under 15 degrees C. The minimum inhibitory concentration of strain I3 for Pb2+ was 7.5 mM, which was higher than that of Escherichia coli DH5 alpha (1.5 mM). However, acid digestion results showed that these two bacteria had a comparable biosorption capacity for Pb2+, suggesting no direct relationship between biosorption ability of bacteria and their metal-resistance. Acid digestion results also proved that intracellular Pb accumulation was mainly contributed to the distinct performance between living and non-living biosorbents, which was further confirmed by the analyses of TEM-EDS: Results of FTIR revealed that functional groups including -CH2, C=O, C-N, N-H, -COO and -SO3 were participated in the biosorption process of the tested biosorbents no matter bacteria were living or not. The effects of environmental factors including pH, temperature, biomass dose, operation time and initial Pb2+ concentration were investigated through a batch of biosorption experiments. The equilibrium data for living and non-living biosorbent were well fitted to Langmuir model with their maximum Pb2+ biosorption capacities of 49.48 and 42.37 mg/g, respectively. The kinetic data for each biosorbent were well described by pseudo-second order kinetic model. Overall, Pseudomonas sp. I3 seemed to be an effective biosorbent for cleansing Pb2+ from contaminated wastewater at low temperature. (C) 2017 Elsevier Ltd. All rights reserved
A consistent ecosystem services valuation method based on Total Economic Value and Equivalent Value Factors: A case study in the Sanjiang Plain, Northeast China
No full textIn this study, a regional revision coefficient is proposed for the Equivalent Value Factors to better valuate the Sanjiang Plain (in China) ecosystem services. An index system suitable for the valuation of the ecosystem services in the Sanjiang Plain is established. The proposed method can realize the rapid valuation of nine ecosystem service types of six different terrestrial ecosystems. Through the preliminary application of the method, the calculated total value of ecosystem services of the Sanjiang Plain in 2010 was 510.89 billion yuan, of which the forest ecosystem contributed to 37.85%, followed by water bodies and wetland ecosystems. The variations among the contributions of the different ecosystem services are considerable. The contribution attributed to regulation function was the highest, especially the value from the hydrological regulation (36.17%) and climate regulation (16.04%). The Total Economic Value (TEV) method and the Equivalent Value Factors (EVF) method are compared in this study. Results show that Equivalent Value Factors derived value of the Sanjiang Plain ecosystem services is slightly lower than the value obtained by the Total Economic Value method, i.e., 537.84 billion yuan, of which the total value of the Feature Services has reached as high as 38.35 billion yuan. (C) 2016 Elsevier B.V. All rights reserved
Effects of wetland vegetation on soil microbial composition: A case study in Tumen River Basin, Northeast China
No full textHydrology plays a dominant role in wetland plant distribution and microbial composition, but few studies explicitly attempted to relate the linkage between wetland vegetation and microbial community. The present study consisted of five wetland plant communities along three adjacent flood gradients zones (zone 1 dominated by Carex appendiculat, zone 2 dominated by Eleocharis ovate, and zone 3 dominated by Phragmites australis/Bidens pilosa/Calamagrostis angustifolia, which formed separate, monoculture patches). Gram negative and arbuscular mycorrhizal fungal phospholipid fatty acid (PLFA) are more abundant in the site with short flooding period (zone 3) than in the site with long flooding period (zone 1), and they are also different in the P. australis, B. spilosa and C. angustifolia of zone 3. Principle Component Analysis (PCA) showed that the flooding period could explain 92.4% of variance in microbial composition. Redundancy Analysis (RDA) showed that available nitrogen (AN), total nitrogen (TN) and soil organic matter (SOM) could explain the 79.5% of variance in microbial composition among E. ovata, P. australis, B. pilosa and C. angustifolia. Results demonstrated that flooding period was the main factor in driving the microbial composition and plant-derived resources could influence soil microbial composition in the seasonally flooded zones
Monitoring Forest Disturbance in Lesser Khingan Mountains Using MODIS and Landsat TM Time Series from 2000 to 2011
No full textThe widespread changes in forest cover caused by climatological and anthropogenic factors can influence the forest ecosystem and climate system to a great extent. With the increasing availability of remote sensing data, monitoring of forest changes at high temporal resolution and on various scales is becoming more realistic. Though several methods based on time series data have been used to detect forest disturbance, there are few studies paying attention to boreal areas where the forest is significant in regulating the global carbon cycle and biogeophysical processes. In this paper, we present a robust method of Breaks Detection Based On Polynomial Model (BDPM) to track boreal (e.g. Lesser Khingan Mountains) deforestation and forest fires based on the MODIS and Landsat TM time series data. Compared with the previous methods, the BDPM offers the following advantages: (1) Fitting of the polynomial model using the seasonal variation of forests in the whole region instead of a single pixel to avoid error accumulation; (2) to avoid confusion between vegetation change due to climate changes and abrupt forest disturbances, we segmented the long-time NDVI series data into 12 seasonal cycles and simulated the temporal variations in each seasonal cycle
Evaluation of riparian condition of Songhua River by integration of remote sensing and field measurements
No full textRiparian zone is crucial to the health of streams and their surrounding environment. Evaluation of riparian condition is essential to achieve and maintain good stream health, as well as to sustain ecological functions that riparian areas provide. This manuscript is aimed to evaluate riparian conditions of Songhua River, the fifth longest river in China, using physical structural integrality (PSI) values derived from remote sensing and validated by field measurements. The variation and clusters of PSI values were discriminated by the spatial statistics to quantify variation of riparian condition in each measurement section. Evaluation results derived from 13 measurement sections indicated that over 60% of the riparian zones have been disturbed by human activities. Analysis of land use patterns of riparian zone in the cold and hot spots found that land-use patterns had an important effect on riparian condition. The build-up and farmland areas had been the main human disturbances to the riparian condition, which were increased from 1976 to 2013. The low-low clusters (low PSI values with low neighbors) of PSI values can be implemented to identify the vulnerability of the riparian zone