饥饿对麻雀体内纤维素酶活性的影响

[目的]探讨饥饿对麻雀体内纤维素酶活性的影响。[方法]采用DNS法,测定自由进食和饥饿组麻雀体内纤维素酶活性的变化,并研究了pH和温度对纤维素酶活的影响。[结果]随着饥饿时间的延长,麻雀胃和肠道内CMC酶活先迅速下降后有部分上升,但未达到对照组的水平。饥饿组BG酶的活性持续下降。肌胃、腺胃、前肠、后肠和直肠中CMC酶活的最适pH分别为3、4、4、6和5。肌胃、腺胃、后肠和直肠的最适温度均为50℃,前肠的最适温度为40℃。BG酶活的最适pH均为4,最适温度为40℃。[结论]饥饿使麻雀消化道内CMC酶活先下降后上升,BG酶的活性持续下降。     

哈尔滨市不同生境类型春季麻雀种群密度差异分析

城市中不同功能区内的生境环境各不相同,常见的功能区为景区、人工林、校园及居民区,研究城市不同生境类型对麻雀种群数量的影响可以对城市进一步建设和管理提供参考。本试验选取哈尔滨市太阳岛部分景区、东北林业大学林场、哈尔滨医科大学校园及哈尔滨市南岗区大众新城居民小区作为研究点。通过样方与样线法采集不同生境下的麻雀数量,使用SPSS 19. 1软件进行分析得到麻雀的种群密度。通过t检验得出结论为:城市不同功能区内的同一绿地种类中麻雀种群密度之间差异极显著,就均值来看麻雀种群密度大小依次为:太阳岛、大众新城、哈医大校园、东北林业大学林场,因此相对来说麻雀更喜欢太阳岛(风景区),其次是大众新城(居民区),然后是哈医大(高校校园),最后是校林场(人工林)。同时,通过t检验得到高校校园功能区中不同绿地种类的麻雀种群密度间差异也极显著,结果中均值显示麻雀种群密度从大到小依次为:林草混合地、林荫路、草地,因此相对来说麻雀更喜欢林草混合地,其次是林荫路,最后是草地。     

城市化对麻雀数量与分布的影响——以北京为例

随着中国各地城市化进程的加快,城市中麻雀(Passer montanus)的生存可能受到食物和栖息地缺乏的影响.我们以北京为例研究了城市化对麻雀数量和分布的影响.结果表明:麻雀的丰富度与城市化分数呈显著负相关,高层居民区、商业中心以及主干道两侧的麻雀丰富度显著较低,而公园、校园、低层居民区以及城郊区的麻雀丰富度显著较高;50 m尺度内针叶树的数量和硬化地面积以及200 m尺度内高层建筑和植被面积是影响冬季麻雀分布的主要环境因子;50 m尺度内的低层建筑面积、针叶树数量、硬化地面积以及400 m尺度的高层建筑和植被面积是影响繁殖期麻雀分布的主要环境因子.以上结果表明尽管麻雀是一种适应人类环境的鸟类,然而高度城市化的区域不适合麻雀的栖息.我们建议将城市鸟类的栖息纳入未来的生态城市规划中.     

Impact of Macrotermes termitaria as a source of heterogeneity on tree diversity and structure in a Sudanian savannah under controlled grazing and annual prescribed fire (Burkina Faso)

Macrotermes termitaria are conspicuous features of savannah ecosystems in the Sudanian and Sahelian zones of West Africa. The mounds, alive or abandoned, are a major source of heterogeneity in the landscape. The purpose of the present study was to assess the impact of termitaria on tree community in a state forest of the Sudanian regional centre (Tiogo forest, Burkina Faso), under controlled burning and grazing experiments. A comparative inventory was carried out in a split-plot experiment (16 subplots of 2500 m²): 8 subplots where fire regime and grazing were controlled and 8 subplots exposed to grazing and with annual prescribed fire since 1992. All tree individuals (≥1.5 m) were recorded, both on termitaria and outside and their basal area at stump level was measured. A total of 61 observed (or 65.7 ± 2.4 estimated) tree species were recorded on 28 Macrotermes subhyalinus mounds (54 observed species or 60.8 ± 3.3 estimated), the immediate surroundings (44 observed and 59.0 ± 0.0 estimated species) and the rest of subplots (56 observed and 63.6 ± 0.0 estimated). Specific density was higher on mounds in comparison with the surroundings (P < 0.05). Results showed that termitaria played a key role in maintaining higher species diversity as compared to their surroundings (P < 0.05). Differences in species diversity between termitaria and immediate surroundings appeared more pronounced in disturbed plots (submitted to both fire and grazing). Some species, such as Tamarindus indica, Boscia senegalensis, Cadaba farinosa, Capparis sepiaria and Maerua angolensis are found solely on termitaria. Besides, the density of trees was significantly higher on termitaria compared to the surrounding (P < 0.05), as well as total basal area per unit of 100 m² area (P < 0.05). We concluded that Macrotermes termitaria play an important role as a source of heterogeneity in this Sudanian savannah woodland ecosystem. This role is particularly important in ecosystems under stresses. Termitaria acted as refuge for tree vegetation. The density and dynamics of M. subhyalinus termitaria should, therefore, be taken into account in the global strategy of the forest resources management and conservation.     

辩证看待麻雀残食庄稼

分析麻雀增多原因,提出雀灾是局部性的、麻雀是庄稼的卫士、麻雀不可随意捕杀等观点,对麻雀危害庄稼作了客观评价,提出低值粮食喂食、药物驱赶、使用凶猛动物粪便、引进天敌、适当捕杀等科学驱鸟方法。     

Phacoemulsification in an adult Savannah monitor lizard

An adult male Savannah monitor lizard (Varanus exanthematicus) was presented for bilateral lens opacities that had progressed rapidly over the previous 2 months. A diagnosis of bilateral mature cataracts was made and phacoemulsification cataract extraction was performed. Surgery restored vision and normal activity to the patient.     

Effect of continuous maize-cropping on yield,organic carbon mineralization and phosphorus supply of savannah soils in western Nigeria

Summary Sixty surface soils collected from major soil classes in the western Nigeria savannah were cropped to maize 6 times in succession without P fertilization. Dry matter yields, %P and P uptake decreased significantly until the sixth cropping. Organic matter decreased with cropping but no significant loss in total P was recorded. Inorganic P and saloid-bound P decreased, while organic P, Al-P, Ca-P and Fe-P increased. All the changes had little or no relationship with yield and P uptake while contributions from saloid-bound and Al-P utilization by maize were indicated. Bray's P₁ available P decreased until the fourth cropping, but increased afterwards. The increase notwithstanding, lower correlations were obtained with yield and P uptake of the succeeding crops.     

Partnering with local communities to identify conservation priorities for endangered Grevy’s zebra

Setting wildlife conservation priorities and determining how to meet them is challenging, particularly when policy decisions made at large scales need to be informed by a diversity of local conditions. The persistence of species that range widely demands that they coexist with people both within and outside formally protected areas. It is often politically and financially infeasible for one central body, such as a government wildlife agency, to monitor an entire population. Therefore, conservation planners are increasingly turning to local knowledge to inform conservation decisions. Here, we show the scientific and conservation benefits of recruiting and training local community members to collect data on an endangered species, the Grevy’s zebra (Equus grevyi). We recruited 18 scouts from six community-held ranches in Samburu District, Kenya. The scouts record the location, group structure and habitat of all Grevy’s zebra herds seen in walking surveys. Kernel analyses of scout herd observations indicate areas heavily used by Grevy’s zebra, and the subset of these areas favored by females with young foals. The important areas identified by the scouts closely match those inferred from analyses of GPS radiocollar data. Further, scout data reveals extensive spatial and temporal overlap between livestock and Grevy’s zebra. This overlap suggests the potential for competition between Grevy’s zebra and domestic animals. We argue that scout programs such as ours can generate valuable insights for conservation planning. In addition, such programs have the potential to improve local attitudes toward wildlife conservation.     

Examining the product and process of scenic beauty evaluations using moment-to-moment data and GIS: The case of Savannah,GA

Growing out of a recent debate on aesthetics, and in particular scenic beauty, we added the term ‘process’ to our conceptualization of scenic beauty so it is broader and more dynamic than other traditional definitions. The purpose of this study is to evaluate the product (content of the environment such as tree characteristics) and process (spatial and temporal patterns of change perceived such as frequency, maximum, minimum, and average quality) of scenic beauty tourist evaluations to better understand what and how it is experienced in real-time. Five city street corridors in Savannah, GA, were video recorded with a roadside view during the spring, summer, and winter (2008–2009). Visitors (N = 130) were asked to evaluate the scenic beauty of a video by turning a hand-held dial (Perceptual Analyzer) and completing a questionnaire. Moment-to-moment data, post-video evaluations, and GIS tree data were used to develop a scenic beauty map, evaluation timelines for each season, and a model predicting willingness-to-pay for a trolley tour. The specific tourism product-based characteristics of the urban forest (tree groupings, height, diameter or DBH, age, condition, and species) that contribute to scenic beauty support what is reported in the literature, thus further validating the mapping of real-time data. Both quality (i.e., average scenic beauty) and quantity (i.e., positive changes in scenic beauty per minute) related measures were both significant process-based predictors of tourists’ willingness-to-pay for scenic beauty. The only product-based variable that was significant was an overall measure of quantity of visitor experiences (i.e., eventful measure). The quality of scenic beauty may be only part of the story.     

Changes in soil properties related to different land uses in part of the Nigerian semi-arid Savannah

Abstract. Changes in soil physical and chemical properties associated with different land uses including natural savannah were compared in Nigeria. The study was conducted on large unreplicated sites. There was a significant coarsening of texture, depletion of organic matter and nutrients and increase in bulk density under Eucalyptus camaldulensis and Mangifera indica (mango) plantations, and also under arable and fallow conditions compared with under natural vegetation. The soil conditions were slightly better under Mangifera than under Eucalyptus , and in the fallow land than the arable land and tree plantations, but the differences were mostly non-significant. The land uses studied were less efficient than the natural savannah in protecting the soil from loss of organic matter and nutrients by offtake or surface washing. The options open to Nigerian smallholder fanners are discussed in relation to sustaining soil fertility and productivity.