黄土丘陵区农业生态系统和经济系统的互动关系——以安塞县纸坊沟小流域为例

基于1938—2007年黄土丘陵区纸坊沟流域的调查资料,利用生态系统服务价值评估方法和生态足迹理论对该流域生态系统服务价值与生态足迹进行了测算,并分析了研究区农业生态系统与经济系统的互动关系.结果表明:1938—2007年,纸坊沟流域经历了3个阶段,即生态环境破坏-经济发展落后阶段(1938—1975年)、生态环境恢复-经济迅速发展阶段(1975—2000年)和生态环境保持良好-经济稳定增长阶段(2000—2007年);该区生态经济系统的互动关系表现为"生态恶化-生态、经济相互调节、适应-生态、经济良性互动"的过程.

Effect of sugar type on the survival of frozen-thawed rhesus monkey (Macaca mulatta) sperm

Sperm-freezing extenders supplemented with sugar or a combination of different sugars are widely used for the cryopreservation of nonhuman primate spermatozoa. Understanding which sugar or combination of sugars offers the highest level of cryoprotection w

Bird and mammal conservation in Gaoligongshan Region and Jingdong County, Yunnan, China: patterns of species richness and nature reserves

Elevational and latitudinal patterns of species richness for birds and mammals were compared with human population density in relation to nature reserve designation in two areas of Yunnan Province, China. Results suggest that species richness is not the same for the two areas. In Gaoligongshan Region, species richness is inversely correlated with elevation and altitude, while reserve designation is positively correlated with elevation and latitude. In Jingdong County, reserve designations are positively correlated with elevation, but species richness shows no clear trends. In general, the present situation is strongly influenced by human activities. It appears that reserve designation is mismatched with species richness in Gaoligongshan Region, while there is a better fit between the two in Jingdong County. In both areas, however, it appeared that reserves were located primarily in order to reduce conflict with humans rather than to maximize conservation of biodiversity, probably because humans were responsible for forest-especially primary forest-destruction and degradation in the low-lying areas.

Land-cover changes in an urban lake watershed in a mega-city, Central China

Urbanization can exert a profound influence on land covers and landscape characteristics. In this study, we characterize the impact of urbanization on land cover and lacustrine landscape and their consequences in a large urban lake watershed, Donghu Lake watershed (the largest urban lake in China), Central China, by using Landsat TM satellite images of three periods of 1987, 1993 and 1999 and ground-based information. We grouped the land covers into six categories: water body, vegetable land, forested land, shrub-grass land, open area and urban land, and calculated patch-related landscape indices to analyze the effects of urbanization on landscape features. We overlaid the land cover maps of the three periods to track the land cover change processes. The results indicated that urban land continuously expanded from 9.1% of the total watershed area in 1987, to 19.4% in 1993, and to 29.6% in 1999. The vegetable land increased from 7.0% in 1987, 11.9% in 1993, to 13.9% in 1999 to sustain the demands of vegetable for increased urban population. Concurrently, continuous reduction of other land cover types occurred between 1987 and 1999: water body decreased from 30.4% to 23.8%, and forested land from 33.6% to 24.3%. We found that the expansion of urban land has at least in part caused a decrease in relatively wild habitats, such as urban forest and lake water area. These alterations had resulted in significant negative environmental consequences, including decline of lakes, deterioration of water and air quality, and loss of biodiversity.

黄土丘陵区小流域综合治理生态经济过程分析——以宁夏隆德县李太平小流域为例

从生态经济系统分析角度出发,对小流域生态经济结构及其演变进行分析,以期评价小流域生态经济效益。对比分析了小流域生态经济系统土地利用结构及其适宜性、产业结构、消耗结构和饲料生产平衡,利用线性模型对土地利用结构进行了优化模拟,采用描述生态系统稳定性的多样性指数描述流域经济系统稳定性,并用静态和动态模型对治理经济效果进行评价。流域农、林、牧用地比例由1990年的6．2:2．0:1．0变为2003年的1．9:1．4:1．0;农业产值所占比重由79．6％下降为54．8％;林业、牧业、副业产值比例分别由9．6％、9．6％、1．1％上升为22．7％、 15．1％、7．4％。收入多样性指数呈增加趋势,消耗结构趋向合理,饲料供需平衡,经济评价中各指标均显示经济效益显著,表明生态经济结构明显有利于生态经济系统的进展演变,流域生态经济结构趋于稳定,生态经济效益显著。

黄土丘陵沟壑区坡沟植被生态序列研究

植被生态序列是小地形对植被空间分布影响的反映。采用样线法,对安塞纸坊沟支沟拐沟中南北向短坡面深沟谷和长坡面浅沟谷断面进行植被调查,分析其植被生态序列特征、物种组成及物种多样性。结果表明:短坡面深沟谷序列主要以灌乔木等演替后期物种为主,而长坡面浅沟谷序列则主要为草本物种;同一序列中,阴坡、沟谷地具有比阳坡、沟间地复杂的演替后期群落;序列中物种主要由菊科(Compositae)、豆科(Leguminoseae)和禾本科(Gramineae)构成,生活型主要为多年生草本,生态型以旱生、中旱生为主。α多样性指数在阴坡和短坡面深沟谷序列较高,β多样性指数在地形变化活跃的沟缘线区较高。研究结果可为黄土丘陵沟壑区植被建设人工调节提供参考依据。