Informatics Publishing Limited

Xiaoteng Xu ¹, Kebin Zhang ¹, L. L. Wang ¹, R. P. Hou ¹, V. Squires ²

Affiliations
1 School of Soil and Water Conservation, Beijing Forestry University, Beijing 100083, CN
2 Adelaide 5892, AU

Abstract

Artificial enclosure has been an important and practical measure widely used to restore vegetation in the ecologically degraded area. In this study, using a standard plot investigation method, we investigated the changes in biomass and species diversity of the plant communities in the desertified grassland located in Ningxia Autonomous Region, China, after enclosure for 0, 5, 15 and 25 years with fences made up of cement piles and barbed wires, with a complete exclusion of interferences from any activities including grazing. We also analysed the factors driving the changes in these parameters. The results showed that with the increase in the enclosure duration, the soil electrical conductivity and nutrient contents were significantly increased but the thickness of biological crust in the deserted area was not changed regularly and the soil pH values were changed only slightly. Furthermore, while no significant differences in plant biomass, species abundance and α-diversity were seen, significant difference in β-diversity was seen among different enclosure years. Principal component analysis showed the significant differences in species compositions in the deserted grassland among various enclosure years. The redundancy analysis revealed that the available nitrogen, available potassium, soil organic carbon and soil electrical conductivity were the major factors affecting the plant species compositions in the deserted area in the studied region. These findings can be of practical significance for formulating the measures to effectively curb the deterioration of ecological environment in grassland.

Keywords

Biological Soil Crust, Species Diversity, Biomass, Redundancy Analysis, Fencing.

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Xiaoteng Xu ¹, Kebin Zhang ¹, Lili Wang ¹, Zhiru Hao ¹, Victor Squires ², Li He ¹

Affiliations
1 School of Soil and Water Conservation, Beijing Forestry University, Beijing 100083, CN
2 Dryland Management Consultant, Adelaide 5892, AU

Abstract

Ten kinds of antibiotics belonging to tetracyclines, sulfonamides, quinolones and macrolides were detected in water samples from Haihe River, China. Sulfamethoxazole and sulfachlororyridazine had largest detection frequencies (100% and 86%), with the maximum concentrations of 330 ng/L and 380 ng/L, respectively. Friedman and Moran's I test indicated that the target antibiotics at different sampling sites were significantly different (p < 0.05), suggesting that the antibiotics detected in the Haihe River were primarily depended on proximal sources of antibiotics. Municipal wastewater plants, fishponds, and livestock's industries along the river were confirmed to import antibiotics to the tributaries, and then distribute into the mainstream. By studying the variations of relative compositions of antibiotics in both surface water and sediment, we found that sulfonamides had a much higher migration capacity than other antibiotics, quinolones and macrolides deposited in sediment after travelling short distance from sewage outfall and tetracyclines in pollution sources was strongly absorbed in the sediment.

Keywords

Antibiotics, Haihe River, Pollution Sources, Migration Capacity.

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Lili Wang ¹, Kebin Zhang ¹, Ruiping Hou ¹, Xiaoteng Xu ¹, Xiao Wang ¹, Xiaodan Liu ¹

Affiliations
1 School of Soil and Water Conservation, Beijing Forestry University, Beijing 100083, CN

Abstract

Fencing has been used as a main measure for rangeland and pasture rehabilitation all over the world. By quadrat method, the vegetation of Yanchi County of Ningxia Hui Autonomous Region has been investigated for the impacts of different fencing time on vegetation community structure and biomass. The result shows that it increases biodiversity and makes the vegetation community more stable. But long time fencing is not conducive to vegetation recovery. The Biodiversity Index in the edge areas and peripheral areas reached to highest level in the 4^th and 5^th year after fencing respectively. The Richness Index (R₁) and Comprehensive Diversity Index (D, H) of the edge areas are 22, 2.26, 6.18, and those in the peripheral areas reach to 13, 1.67 and 3.24. Then biodiversity index decreased as fencing time increases. Under different fencing measures, the Biodiversity Index in the core area is the highest. So fencing is an effective measure for vegetation restoration. The vegetation coverage and biomass in the peripheral areas are the largest. This shows that rational uses of grassland are beneficial to vegetation recovery. Strip tillage doesn't have obvious effects on vegetation recovery, and it suggested that grazing or cutting can be used in this region for rangeland and pasture rehabilitation.

Keywords

Fencing Time, Exclusion Measures, Biodiversity, Sandy Rangeland, Semi-Arid Area.

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