Analysis of relationship between soil erosion and lake deposition during the Holocene in Xingyun Lake, southwestern China

Quantifying the relative influences of anthropogenic activities and climate change on soil erosion and deposition during the Holocene, when both forces have been interacting is a complex problem. Analysis of long-term patterns in soil erosion and lake deposition in a basin can provide the basis for untangling the complexities of climate and anthropogenic forcings. In this paper, sedimentary sequences from Xingyun Lake are compared with simulated soil erosion rates in the basin to explore the relationship between river basin soil erosion and lake deposition during the Holocene in Yunnan, China. Modern soil erosion rates are calculated using RUSLE, while Holocene soil erosion rates are estimated using modern rates with reconstructed precipitation and vegetation cover sequences. Through this investigation, we found the following results. First, Holocene vegetation in the lake basin was mainly affected by climate change, and the vegetation experienced the same pattern of changes as the climate. Soil erosion and lake deposition rates, along with changes to vegetation cover, were synchronous with precipitation trends during the Holocene. Second, soil erosion and lake deposition have been exacerbated by human activities, such as deforestation and land reclamation in the Xingyun Lake basin. Finally, this study provides new insights into the effects by anthropogenic impacts and climate forcing on the processes of soil erosion and lake deposition on the millennium scale.

New records of freshwater ostracoda from the xingyun lake

<p>This present paper reports eight modern ostracode collected from the bottom of the Xingyun Lake,Yunnan Province, including Candonocypris novaezelandiae (Baird, 1843), mateless cyclocypris Cypridopsis Vidua (O.F.M ller, 1776), star (which really wedge dielectric) Eucypris CF. Cuneata (Tsao, 1959), Cleveland star kraeplini (G.W.M mediated Cypris ller, 1903) Belgium, sheshi (similar) glass dielectric Schellencandona CF. Belgica (Klie, 1937), Fabaeformiscandona subacuta (Yang, 1982), unarmed mobs mediated Cetacella inermis (Martin, 1958), the Yunnan flower (compare kinds) Yunnanicyhere cf.reticulate mediated gen.etsp.nov. the true star (dielectric wedge comparison of three) Eucypris CF. Cuneata (Tsao, 1959), unarmed mobs mediated Cetacella inermis (Martin, 1958) and Yunnan (a comparison of dielectric reticulate flowers) Yunnanicyhere cf.reticulate gen.etsp.nov.  these species are newly recorded from modern lakes.It has enriched the understanding of freshwater ostracoda of the biological communities in China.</p><p><strong>Key word</strong><strong> </strong> freshwater ostracods; Xingyun Lake; Yunnan Province</p>

LUCC impact on water quality change in Xingyun Lake basin

Basin ecological environment and water quality are seriously threatened by development around the lake. The thesis intends to assess basin Land Use and land Cover Changes (here after abbreviated as LUCC) impact on water quality change in Xingyun Lake basin. To achieve this purpose, land use information was interpreted from six periods high-resolution images in the past 30 years, which were classified into seven land use types. The water quality data was obtained by investigation and collection. SPSS software was used to celebrate the correlation coefficient between water quality and LUCC. The results revealed that, in the study area construction land, transportation land and farm land were underwent an increase with the region development; grassland and bare land were gradually reduced, forest land had become fragmented. In addition, the water pollution index gradually increased since 2000, the water deteriorated significantly. Furthermore, there was a strong positive correlation between water pollution indicator and farmland, construction land and transportation land, which indicated that the deterioration of water quality may be the result of the combined effects of agriculture non-point source pollution, domestic and industrial pollution; there was a significant negative correlation between water pollution indicator and grassland and bare land, which indicated that permeable underlying mat had significant interception and absorption effects on pollutants.