Wang Xinyuan

Environmental changes during early-middle Holocene from the sediment record of the Chaohu Lake, Anhui Province

A typical lake sediment core is obtained from the Chaohu Lake in the lower reaches of the Yangtze River, Anhui Province, China. The timing scale is constrained by AMS 14C dating method. Climate proxies such as pollen and grain size in the core are analyzed to reconstruct the environment changes at this site approximately between 9870 and 2170 cal. a BP. The results indicate that at the research area, the climate in the early-middle Holocene had evolved through 3 stages. From 9870 to 6040 cal. a BP, proxy records show a warm and dry climate with low water levels after the late-glacial period. During this stage, cool and dry events occurred at about 8910 and 6060–6030 cal. a BP. Then, between 6040 and 4860 cal. a BP, the climate was humid and vegtation was more flourishing in the Chaohu Lake Valley. The Holocene Optimum occurred at 5840–5500 cal. a BP in the Chaohu Lake, showing the best condition of water and heat. Elm Decline occurred at the period of 5380–4930 cal. a BP. Since 4860 cal. a BP, the climate was warm and dry through 2170 cal. a BP as shown in both pollen spectrum and grain-size histories. Two obvious dry events occurred in 3760 and 2170 cal. a BP, respectively. At 2170 cal. a BP, the water level of the Chaohu Lake reached the lowest as the lakebed possibly exposed. Such lake sediment observations are consistent with the historical records in this area.

Impact of earthquake-induced landslide on the habitat suitability of giant panda in Wolong, China

Massive geological landslides and unstable landslide areas were triggered by the 2008 Wenchuan earthquake. These landslides caused deaths, damaged infrastructure and threatened endanger species. This study analyzed the impact of landslides on giant pandas and their habitats from the following aspects: threatening pandas’ lives, damaging pandas’ habitat, influencing giant panda behavior, increasing habitat fragmentation; the final aspect, and blocking gene flow by cutting off corridors. A habitat suitability map was created by integrating the landslide factors with other traditional factors based on a logistics regression method. According to the landslide inventory map, there are 1313 landslides, 818 rock debris flows, 117 rock avalanches and 43 mud flows occurred in the study area. A correlation analysis indicated that landslides caused the pandas to migrate, and the core landslides within 1 km2 had greater influence on panda migration. These core landslides primarily occurred in mid-altitude regions characterized by high slopes, old geological ages, large areas and large rock mass volumes. The habitat suitability assessment results for the Wolong Natural Reserve had better prediction performance (80.9%) and demonstrated that 14.5%, 15.9%, 20.5%, 47.6% and 1.5% of the study area can be classified as very high, high, moderate, low and very low giant panda suitability areas, respectively. This study can be used to inform panda and panda habitat research, management and protection during post-quake reconstruction and recovery periods in China.

Research on algae blooms forecasting based on the multivariate data driven method: a case study of the Chaohu Lake

The data driven is one of the main methods for forecasting algae bloom, which requires lots of continuous and accurate monitoring data. It is an effective way to increase sample data size by combining in-situ, and remote sensing data. The Chaohu Lake was taken as the case study. Based on water quality data (TLI), meteorological data (sunshine duration, temperature, wind speed, wind direction) and bloom grade data, provided respectively by remote sensing and in-situ monitoring, an artificial neural network was employed to build empirical data-driven models. The model accuracy was evaluated by algae bloom grade recognition rate and bloom trend recognition rate. The results showed that the bloom grade recognition rate of model driven by remote sensing data was better than others. Bloom trend recognition rate of model driven by in-situ data is higher than others. These results provide some insights for algae bloom forecasting.

Paleodrainage detection with Shuttle Imaging Radar and Radarsat in Alxa Plateau in China

Alxa Plateau is located in Central-north of China with average altitude of 1000 m a.s.l.. The Gobi desert and relict mountains characterizes the area. There are also many playas in the plateau. This is one of the driest area both in China and in the world. Based on radar penetration, through the analysis to SIR-A, SIR-B, SIR-C, Radarsat ScanSAR images obtained on different dates and several times field investigation, some subsurface old river valleys and buried lake basins were recognized, thus an old drainage composed with rivers and lakes can be delineated. Through this research, the preliminary drainage evolution process of this 300,000 km/sup 2/ area since Tertiary period is established.