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71.
姜仕仁  丁平 《动物学研究》2003,24(2):132-136
对杭州春季(3-5月)5种庭园常见鸟的晨鸣做定点和定个体录音,然后用计算机声谱分析系统处理录音。结果表明:同域鸟类的晨鸣有一定的时序;乌鸫最早鸣叫,而大山雀、白头鹎和鹊鸲的始鸣时序有月间变化。5种鸟晨鸣的主频集中在2.4-4.1kHz;除了鹊鸲和麻雀无差异外,其余均有极显著差异;这种差异为进一步研究群落内种间频域竞争提供了部分基础资料。  相似文献   
72.
Aim We aim to assess regional patterns in the distribution and species richness of vascular epiphytes with an emphasis on forests that differ in altitude and the amount of rainfall. Location Tropical America, in particularly the 75,000 km2 large state of Chiapas in southern Mexico at 14.5–18.0°N. Chiapas is diverse in habitats with forests from sea‐level to the tree‐line at c. 3800 m altitude and with annual amounts of rainfall ranging from 800 to over 5000 mm. It is also one of the botanical best‐explored regions in the tropics. Methods First we give an overview of epiphyte inventories to date. Such epiphyte surveys were mostly carried out on the basis of surface area or individual trees and we discuss their problematic comparison. Applying a different methodological approach, we then used 12,276 unique vascular epiphyte plant collections from Chiapas that are deposited in various botanical collections. The locality data were georeferenced and compiled in a relational data base that was analysed using a geographical information system. To compare the number of species between inventories that differed in the numbers of records, we estimated the total richness, SChao, at each. Results We recorded 1173 vascular epiphyte species in thirty‐nine families (twenty‐three angiosperms), comprising c. 14% of all confirmed plant species in the state. About half of all species were orchids (568). Ferns and bromeliads were the next species‐rich groups with 244 and 101 species, respectively. Most species were found in the Montane Rain Forest and in the Central Plateau. Trees of different forest formations, rainfall regimes, altitudes and physiographical regions supported a characteristic epiphyte flora. Main conclusions We were able to confirm the presumed presence of a belt of high diversity at mid‐elevations (500–2000 m) in neotropical mountains. In contrast to predictions, however, we observed a decrease in diversity when the annual amount of rainfall exceeded 2500 mm. The decrease is attributed to wind‐dispersed orchids, bromeliads and Pteridophyta that may find establishment problematical under frequent downpours. In the wet but seasonal forests in Chiapas, this decrease is not compensated by plants in the animal‐dispersed Araceae that are abundant elsewhere. We presume that in addition to the annual amount of rainfall, its distribution in time determines the composition of the epiphyte community.  相似文献   
73.
城市可持续发展能力的能值评价新指标   总被引:20,自引:0,他引:20  
陆宏芳  叶正  赵新锋  彭少麟 《生态学报》2003,23(7):1363-1368
能值理论、方法克服了传统能量与经济分析方法的诸多缺憾,为城市可持续发展的研究提供了全新的视角。但作为一种新兴的理论,其评价指标,尤其是针对城市可持续发展能力的综合评价指标尚不完善。从生态经济效益及环境影响的全面表达角度,剖析了国际现行可持续发展能值指标(ESI)的不足之处,并在此基础上拓展构建了新的可持续发展能值指标(EISD)。以珠江三角洲中山市1996~2000年的发展动态为例进行了案例研究。结果表明,新拓展的可持续发展能值指标.在系统效益评价中考虑了系统能值产出的实际经济效果,在环境影响评价中同时考虑了系统的消耗影响和排放影响,可以更全面明晰的评价城市系统的可持续发展能力、状态及其成因,为系统的优化指明方向。  相似文献   
74.
大气污染对35种园林植物生长的影响   总被引:26,自引:1,他引:25  
对广东省佛山市大气监测的结果表明,酸性硫化物和毒性氟化物是陶瓷工业产生的主要污染物质。采用现场盆栽试验方法。比较分析了生长在佛山市陶瓷城附近高浓度SO2和氟化物大气污染环境下的35种园林绿化植物的株高、基径、冠幅等生长指标的差异,并采用综合生长指标评价方法对参试植物进行相应的抗性分级,选出8种抗性植物(铁冬青、菩提榕、环榕、仪花、小叶榕、红花油茶、幌伞枫、白桂木),17种中等抗性植物(小叶胭脂、腊肠树、毛黄肉楠、红桂木、茶花、吊瓜、火焰木、铁力木、柳叶楠、猫尾木、灰莉、密花树、海南红豆、复羽叶栾树、灰木莲、大头茶、印度紫檀),8种敏感植物(华润楠、海南木莲、格木、日本杜英、蓝花楹、观光木、蝴蝶树、白木香、乐昌含笑、无忧树)。  相似文献   
75.
Housefly is a significant domestic pest, which causes nuisance. The use of insecticides is discouraged to manage housefly; therefore, alternative management strategies are inevitable. The current study investigated the impact of different plant extracts, i.e., Moringa oleifera (moringa), Allium sativum (garlic) and Piper nigrum (black pepper) on biological parameters of house fly. Two different concentrations (i.e., 25 and 50%) of the extracts were blended in larval diet made through mixing of wheat bran, yeast and dried milk powder. The results indicated significant differences for larval duration. Maximum larval duration was recorded for garlic followed by black pepper and moringa, respectively. In case of pupal duration, non-significant differences were observed among plant extracts. Increase rate of oviposition was noticed with moringa at 25% concentration, while decreased oviposition rate was noted for garlic with 50% concentration. Egg hatching percentage remained non-significant for the botanical extracts. The highest survival was observed with moringa, while garlic resulted in the lowest survival. The highest repellency was noticed for garlic followed by black pepper, whereas moringa resulted in the lowest repellency after 30, 60 and 90 min. Prolonged developmental time was observed for bot concentrations of garlic, whereas moringa noted the shortest developmental time. Thus moringa was found to be a promoter of housefly development. Minimum adult emergence was found with both concentrations of garlic followed by 50% concentration of black pepper. The 50% concentration of black pepper promoted the population of adult males, while both concentrations of moringa and 25% concentration of black pepper encouraged the population of female adults. Study outcomes depicted that tested botanical extracts had significant potential for disturbing biological parameters of housefly. The garlic extracts can potentially be used to manage housefly. However, further investigations on the larval and adult mortality are needed.  相似文献   
76.
77.
基于生态网络分析的南京主城区重要生态斑块识别   总被引:5,自引:0,他引:5  
在城市化程度较高,用地极为紧张的大都市,识别重要的生态斑块对其进行保留和修复不仅对控制大城市的城市过度扩张、提升城市品质、优化人居环境具有重要意义,也具有较强可操作性。以南京市主城区为例,在GIS技术的支撑下,(1)将景观阻力分析和网络分析相结合,定量表征研究区的潜在生态廊道,构建生态网络,寻找生态节点;(2)对城市中生态斑块的特殊服务功能进行分析,筛选出具备河流生态防护、隔离工业污染和居民休闲功能的生态斑块;(3)对生态斑块的规模进行分析,提取面积较大的斑块。综合分析后识别出7个重要的节点斑块,建议对其进行立法保护和修复,划定为永久绿地或永久生态空间,并对其建设方向提出意见。  相似文献   
78.
"中心和边缘"假说认为非洲是人类演化的中心地区,东亚等地区是边缘地区。在边缘地区,人群的地区性形态特征出现较早,可上溯到直立人生活时期;在中心地区,人群的地区性形态特征出现较晚。Bodo人类头骨化石和南京1号人类头骨化石分别出自中心地区和边缘地区,二者年代都是距今60万年左右,二者都保留有面颅。因此,Bodo人类头骨化石和南京1号人类头骨化石是检测"中心和边缘"假说的最合适的材料。本文是对南京1号和Bodo头骨的面颅测量性特征作比较研究。研究结果表明:1.二者面颅测量性特征上的差别远大于这两个相应地区现代人群之间的差别,提示了人类的地区性体质形态差别早在60万年前就很明显;2.东亚的南京1号人类头骨和东非的Bodo人类头骨尽管同样古老,但各自与当地区的现代人群的面颅上的差异情况并不一致。Bodo头骨与东非现代人群显得差异较大,南京1号头骨与东亚现代人群显得较相近。这种相近,提示了在东亚这个"边缘地区",现代人群的面颅测量性特征可追溯到以南京1号头骨为代表的远古人类那里,而在"中心地区",现代人群的面颅测量性特征还很难与以Bodo为代表的远古人群相联系。本项研究结果与"中心和边缘"假说的推测相符合。  相似文献   
79.
Brandwijk-Kerkhof (ca. 4600 to 3630 cal b.c.) is a Neolithic site, located on a river dune in the Dutch Rhine/Maas river area. The natural vegetation and human impact upon it have been investigated by analysis of pollen and macroremains from four cores that are located at increasing distances up to 20 m from the site. The relationship between the strength of human impact on the vegetation and the distance of the cores from the river dune has been investigated as well. The results show that the natural vegetation on top of the river dune consisted of deciduous woodland, while in the surrounding wetlands alder carr and eutrophic marsh vegetation dominated. Human impact of limited strength resulted in more open and disturbed vegetation. There is no correlation between the strength of the evidence of human impact in the pollen diagrams and the distance of the cores from the river dune. The evidence for presence of crop plants from the cores is compared with evidence from the excavation. The first presence of crop plants from ca. 4200 b.c. onwards corresponds with data from other Dutch wetland sites. Large-scale local crop cultivation cannot however be demonstrated. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.  相似文献   
80.
南京城市扩展过程中聚落斑块的行为特征   总被引:1,自引:0,他引:1  
城市化过程具体表现为聚落斑块在景观上的消涨过程.基于南京地区1988、1998和2003年的Landsat TM影像,将聚落斑块按演变形式分成新生、消亡、延展、收缩、融合、分裂和混合7种变化模式,分析了各类斑块沿城乡梯度带的分布格局.结果表明:1998-2003年研究区聚落斑块的总面积迅速增加,斑块数量、平均斑块面积和最大斑块指数等均保持同步增长趋势,新生型与混合型构成斑块演变的主体,但收缩和消亡斑块的负贡献率也持续上升;各演变类型斑块沿城乡梯度带的空间分布格局在2个时段上不尽相同;1988-1998年,混合型斑块在主城区表现为高密度扩张;1998-2003年则表现为低密度蔓延,主城区外各梯度带则没有明显的阶段性差异,新生斑块的城乡梯度格局在2个时段基本一致,其密度、面积比例在主城区较小,城市边缘区较高,向外则随离主城区距离的增加而递减;延展斑块前一时段在主城区与远郊存在2个高发区,但后一时段远郊的密度与面积比例均显著降低;收缩斑块和消亡斑块的高发区位于主城区及其边缘和远郊;比较各类斑块的城乡梯度格局发现,城市化程度高、速度快的区域,同时也存在相对快速的斑块收缩与消亡过程,主城区与城外各梯度带在扩展模式上存在阶段性差异.  相似文献   
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