汾河水库水源河着生硅藻群落的DCCA研究

对汾河水库3条主要水源河的11个样点95个着生硅藻进行DCCA排序,这11个样点可分为4组,分别指示水质属于-中污带、-中污带、寡污带和清洁带,DCCA第一轴可反映水体污染程度,第二轴反映河流的流速.DCCA排序表明,COD与水体污染状况关系最大.物种多样性研究采用9个多样性指数,各多样性指数随水体污染等级加大而呈现下降的趋势.

Rotifer community structure and assessment of water quality in Yangcheng Lake

Rotifer community structure was investigated in Yangcheng Lake in 2008. Dominant species and species diversity indices were determined and QB/T was used to assess water quality. The annual average density and biomass of the rotifers in Yangcheng Lake was 2 894＋ 1 006 indYL and 12.47± 10.28 mg/L, respectively. The highest densities were observed in the western portion of the lake in March, but the highest biomass occurred in inflowing creeks in September. Within a year of monitoring in Yangcheng Lake, 93 species were identified and the dominant species were found to be Polyarthra trigla, Brachionus angularis, Keratella eochlearis, Keratella valga, Brachionus calyciflorus, and Filinia major. Of the species recorded, 75 were pollution indicator species. Density and biomass exhibited significant positive correlations with water temperature （R=0,209, P=0.003; R=0.446, P=0.000）, but the peak density showed two lags in response to chl a. According to the Jaccard similarity index （S0, the greatest similarity among dominant species occurred between creeks and the eastern part of the lake. The annual average Shannon-Wiener diversity index H＇, Margalef richness index D and Pielou evenness index J were 1.96±0.34, 1.61±0.50 and 0.77±0.10, respectively. In all four areas of Yangcheng Lake, β- mesosaprobic species comprised the largest share of pollution indicator species. These data suggest that Yangcheng Lake is mesosaprobic.

Dynamics of Soil Fauna in Da Hinggan Mountains, Northeast China

The dynamics of soil animals was studied in seven representative forest communities in the north of the Da Hinggan Mountains, Northeast China. The results indicate that it was distinctive in the changes of the numbers of soil animals and groups and diversity in relationship with seasons for macrofauna and meso-micro fauna in the study area. The numbers of the observed soil animals in different months were: October>August>June. Group number was larger in August and October, but smaller in June. The change of diversity index in different months was: August>June>Oc- tober. The biomass for macrofauna in different months was: October>June>August. The composition and number of each functional group was relatively stable. In the community of the predominant soil environment, the percentage of saprophagous animals was higher than carnivorous animals and herbivorous animals. The dynamics changes of sapro- phagous and carnivorous animals were distinctive, increasing from June to October, while the change of herbivorous animals was unremarkable.

The Typical Watershed of the Three Gorges Reservoir Area Soil Erosion Diversity Change on Different Slope Gradients Taking the Meixi River Watershed as an Example

[Objective] The diversity of soil erosion in the Meixi River watershed of the Three Gorges Reservoir Region was analyzed, in order to provide references for governance and protection of ecological environment of the study area. [Method] The soil erosion diversity index and evenness index of the Meixi River watershed in the Three Gorges Reservoir Region were studied based on the TM images in the year of 1988, 1999 and 2010, supported by GIS technology to extract various types of soil erosion in the area with different slope gradients and calculate soil erosion di- versity index and evenness index. [Result~ As slope gradients grew, the diversity in- dex and evenness index of soil erosion decrease after increasing with a turning point from 25~ to 35~. [Conchlsion] The proportion of light-erosion in the study area is 15.57%. Hence, the increase of diversity index and evenness index with gradients of 5^-35~ shows that the higher erosion intensity, the more uniform erosion types and the indexes decreased in gradients higher than 35°, suggesting that the lower erosion intensity, the better environment. Distribution and variation of different land types have close relation with soil erosion diversity and evenness indexes. Though soil erosion problems have been alleviated, by comparing soil erosion diversity index and evenness index, it can be concluded that changes of indexes are lower than 0.02, and soil erosion should be continued to be well controlled.

Differences in Tree Species Diversity and Soil Nutrient Status in a Tropical Sacred Forest Ecosystem on Niyamgiri Hill Range,Eastern Ghats,India

We have quantitatively analyzed the tree species diversity with respect to soil nutrient status in three sites of a sacred forest ecosystem of Niyamgiri hill range, Eastern Ghats, India. Extensive field surveys and sampling were conducted in 3 sites of the hill range： Site 1 Pterocarpus dominated forest （PTF） （19°40＇02.2＇＇ N and 83°21＇23.1＇＇ E）, Site 2 Mangifera dominated forest （MAF） （19°40＇02.8＇＇ N and 83°21＇40.8＇＇ E） and Site 3 Mixed forest （MIF） （19°36＇47.1＂ N and 83°21＇02.7＇＇ E）. A total of 28 families, 42 genera, 46 tree species, and 286 individual trees were recorded on an area of0.6 ha. Tree density varied between 470 and 49o individuals ha and average basal area between 3.16 and l0.04 m2 ha-1. Shannon Index （H＇） ranged from 2.34 to 4.53, Simpson＇s Index ranged from 0.07 to o.09, and equitability Index ranged from 0.7 to 1.34. The number of individuals was highest in the girth at breast height （GBH） class of 50-7o cm. The soil nutrient status of the three forest types was related to tree species diversity. The soil pH value of the three sites reflected the slightly acidic nature of the area. Species diversity was positively correlated with organic carbon and phosphorus and negatively with nitrogen, EC and pH. The results of the current study may be helpful to further develop a conservation planfor tree species in tropical sacred forest ecosystems.

A method for choice of optimum scale on land use monitoring in Tarim River Basin

Optimal scale is one of the important issues in ecology and geography.Based on land-use data of the Tarim River Basin in Xinjiang of China in the 1950s,regarding the area of land use types as the parameter in scale selecting,the histograms of the patches in area are charted.Then,by reinforcing the normalized scale variances(NSV) with 3 landscape indi-ces,the scale characteristics of land use in the Tarim River Basin can be summarized.(1) NSV in the Tarim River up to a maximum at scale of 1:50,000 which is considered appropriate for the Tarim River.(2) Diversity indices of saline land are consistent with NSV's.Diversity indices and NSV of sandy land showed that the appropriate scale is in the same scale domain.There is a significant difference between diversity indices and NSV of forestland and shrub-land.(3) Fractal dimension of sandy land and saline land showed a hierarchical structure at a scale of 1:10,000.Fractal dimension of forestland and shrubland are distributed under the same hierarchical structure in the region.

Reconstruction of Non-Bandlimited Functions by Multidimensional Sampling Theorem of Hermite Type

In this paper, we prove that under some restricted conditions, the non-bandiimited functions can be reconstructed by the multidimensional sampling theorem of Hermite type in the space of Lp（R^n）, 1 〈 p 〈 ∞.