古尔班通古特沙漠生物结皮中土壤微生物垂直分布特征

对新疆古尔班通古特沙漠主要沙丘类型———沙垄的不同部位、不同类型生物结皮中土壤微生物数量变化特征进行研究,结果表明:(1)微生物总数从垄顶至垄间低地呈递增趋势,在沙垄不同部位0~20cm土层中的垂直分布有差异.(2)土壤微生物各类群数量垂直变化规律为:细菌数量在垄顶0~10cm土层中递减,到10~20cm有所回升;在迎风坡和背风坡的0~10cm土层中递增,到10~20cm有所下降;在垄间低地0~20cm土层中呈递增趋势.放线菌数量在各部位均随土层加深而递减.真菌数量在垄顶和迎风坡0~20cm土层中的垂直变化与细菌在垄顶的垂直变化一致,在垄间低地和背风坡,真菌数量均在2~5cm土层中出现峰值,然后随土层加深递减.(3)微生物类群的组成表现为:细菌数量>放线菌数量>真菌数量.在垄间低地细菌所占微生物总数比例相对垄顶有所增加,而放线菌和真菌相应减少.(4)土壤微生物的数量变化特征与生物结皮的类型、分布以及土壤有机质含量等因子有一定相关性.图5表1参34     

Dams,Floodplain Land Use,and Riparian Forest Conservation in the Semiarid Upper Colorado River Basin,USA

Land and water resource development can independently eliminate riparian plant communities, including Fremont cottonwood forest (CF), a major contributor to ecosystem structure and functioning in semiarid portions of the American Southwest. We tested whether floodplain development was linked to river regulation in the Upper Colorado River Basin (UCRB) by relating the extent of five developed land-cover categories as well as CF and other natural vegetation to catchment reservoir capacity, changes in total annual and annual peak discharge, and overall level of mainstem hydrologic alteration (small, moderate, or large) in 26 fourth-order subbasins. We also asked whether CF appeared to be in jeopardy at a regional level. We classified 51% of the 57,000 ha of alluvial floodplain examined along >2600 km of mainstem rivers as CF and 36% as developed. The proportion developed was unrelated to the level of mainstem hydrologic alteration. The proportion classified as CF was also independent of the level of hydrologic alteration, a result we attribute to confounding effects from development, the presence of time lags, and contrasting effects from flow alteration in different subbasins. Most CF (68% by area) had a sparse canopy (50% canopy cover occupied <1% of the floodplain in 15 subbasins. We suggest that CF extent in the UCRB will decline markedly in the future, when the old trees on floodplains now disconnected from the river die and large areas change from CF to non-CF categories. Attention at a basinwide scale to the multiple factors affecting cottonwood patch dynamics is needed to assure conservation of these riparian forests.     

精准扶贫下社区发展基金(CDF)项目的多元管理与机制创新——基于内蒙古阿拉善盟的实证研究

内蒙古自治区阿拉善盟的荒漠生态系统是我国西北地区的一条重要生态防线,其生态环境直接影响到首都北京和华北地区的生态安全。精准扶贫是党和政府推动国家发展的重要战略目标。2015年11月-2017年1月,采用入户访问和半结构访谈的方式,对阿拉善盟开展社区发展基金项目的4个嘎查(村)的农户进行随机问卷调查。并分别在2005年、2008年、2015年对其中两个嘎查参与社区发展基金项目的15位农户的家庭收入和产业结构进行跟踪调查研究。结果表明:该区域将已有社区发展基金项目和政府精准扶贫重点项目相结合,实现了政府资本、社会资本(SEE)、民间资本(村民)的整合和统筹使用,提高了公共资金的使用效率;参加社区发展基金项目后,社区村民的收入结构和产业结构发生了大幅变化,促进了农业的转型升级,即提升了村民的自我管理能力,拓展了村民的收入来源,减轻了村民对区域自然资源的依赖程度,有利于村民的减贫和区域可持续发展。该区域集政府资本、社会资本(SEE)、民间资本(村民)等多方资金为一体的社区发展基金项目,为荒漠复合生态系统的建设和区域经济可持续发展提供了借鉴,是我国当前生态文明建设的有益尝试。     

上海市生态环境功能区划综合评价结果

根据上海生态功能区划方案,划分得到8个生态功能区。为了更为清晰、直观地了解各功能区的生态特征,同时也为了便于进行各功能区之间的比较,开展了生态环境敏感性和生态服务功能重要性的综合评价。根据综合评价结果,黄浦江水源保护生态功能区是生态敏感性最强的区域,而长兴岛功能区的生态敏感性最弱;黄浦江水源保护生态功能区是生态服务功能重要性最高的区域,而长兴岛功能区的生态服务功能重要性最弱。     

杨树产业对宿迁市生态环境的影响及反思

杨树产业所导致的生态环境的破坏是当前宿迁市环境保护工作中出现的新问题。在对宿迁杨树产业的由来、发展现状进行简要介绍后,着重分析了杨树产业对宿迁生态环境的影响,并对如何使宿迁的杨树产业走可持续发展的道路提出了自己的意见,最后还对如何避免此类问题的出现进行了思考。     

河南省农业生态环境分析与生态建设

河南省是一个农业大省,其农业的可持续发展与否,对我国的农业发展有着重要影响。在广泛、深入调查的基础上,分析了河南省农业生态环境存在的主要问题,结合农业生态建设的指导思想及目标,提出了河南省农业生态建设的４大对策。     

Effects of Protective Fencing on Birds, Lizards, and Black-Tailed Hares in the Western Mojave Desert

Lepus californicus ), perennial plant cover, and structural diversity of perennial plants were evaluated from spring 1994 through winter 1995 at the Desert Tortoise Research Natural Area (DTNA), in the Mojave Desert, California. Abundance and species richness of birds were higher inside than outside the DTNA, and effects were larger during breeding than wintering seasons and during a high than a low rainfall year. Ash-throated flycatchers (Myiarchus cinerascens), cactus wrens (Campylorhynchus brunneicapillus), LeConte's thrashers (Toxostoma lecontei), loggerhead shrikes (Lanius ludovicianus), sage sparrows (Amphispiza belli), and verdins (Auriparus flaviceps) were more abundant inside than outside the DTNA. Nesting activity was also more frequent inside. Total abundance and species richness of lizards and individual abundances of western whiptail lizards (Cnemidophorous tigris) and desert spiny lizards (Sceloporus magister) were higher inside than outside. In contrast, abundance of black-tailed hares was lower inside. Structural diversity of the perennial plant community did not differ due to protection, but cover was 50% higher in protected areas. Black-tailed hares generally prefer areas of low perennial plant cover, which may explain why they were more abundant outside than inside the DTNA. Habitat structure may not affect bird and lizard communities as much as availability of food at this desert site, and the greater abundance and species richness of vertebrates inside than outside the DTNA may correlate with abundances of seeds and invertebrate prey.     

干旱荒漠区生态环境趋势和启示

本文在介绍国际干旱荒漠生态环境历史发展过程的同时,指出当今人们所关心的一些问题和重要的研究课题,着重指出经济发展中应该重视干旱荒漠生态环境监测与研究.     

石英Al心和Ti-Li心电子自旋共振信号测年结果对比：以腾格里沙漠白碱湖地区BJ14钻孔中沉积物为例

早—中更新世沉积年代的确定是第四纪研究领域亟待解决的难题,电子自旋共振（ESR）测年法为该时段沉积物定年提供了可能。但已有的研究发现：石英Ti心和Al心ESR信号完全衰退“回零”或达到较稳定“残留”所需时间较长,因而其可信性备受质疑。本研究选取腾格里沙漠白碱湖地区BJ14钻孔中5个不同深度的沉积物,分别基于其中石英Ti心和Al心信号进行了ESR定年。测年结果显示：（1）2个样品基于Al心ESR信号与基于Ti-Li心ESR信号的测年结果在年龄误差范围内一致,其它3个样品Al心ESR测年结果较Ti-Li心测年结果偏老200—500 ka;（2）与该孔的古地磁测年结果对比表明,石英Ti-Li心ESR测年结果相对可靠。上述研究结果表明石英Ti-Li心的ESR测年结果至少能提供中更新世更为可信的沉积年龄。     

The impact of off-road vehicles on a desert ecosystem

The effects of operating a 4-wheel drive truck in a 9-ha area of the Mojave Desert were evaluated. A truck was driven over the same 0.9-km track 21 times between November 1973 and May 1974. The vehicle was also driven randomly around the area (1.3 to 3.4 km) 17 times between December 1973 and May 1974.Spring densities of annual plants in ruts of the regular track (8/m²) were less than those in control areas (46–112/m²), but densities in randomly driven plots (39/m²) did not differ significantly from controls. Severity of damage to shrubs was directly related to intensity of driving in the area. About 58% of shrubs growing in the regular track sustained estimated damage ranging from 81 to 100%. In randomly driven areas only 6% of shrubs were damaged to this extent, while about 61 % sustained damage from 0 to 20%.Numbers and kinds of rodents in control and driven areas were similar before and after the experiment. More young rodents were trapped in the experimental plot than in the control area during July 1974, and this may have been promoted by basal sprouting of new growth by damaged shrubs. Estimates of numbers of side-blotched lizards indicated similar densities before, during, and after the experiment. Counts of whiptail lizards in control and experimental areas were the same after the experiment, but counts of gridiron-tailed lizards were much lower in the driven area.