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1.
畜牧业地域生态类型是指具有明显地域性生态特点的畜种结构或畜群结构和饲养经营方式的组合。桃源县境内地形复杂,具有山地、丘陵和平原等地貌类型,地势由南、西向东部逐渐低降,由此引起明显的畜牧业地域性差异。作者采用聚类分析的方法,选择了地貌、饲料资源、载畜量、畜禽结构和畜牧经济等五个因子集和20个因子,经微型电子计算机运算,将桃源县畜牧业地域生态类型分为三类、八亚类:第一类为平原岗地猪鸡鸭免类,第二类为丘陵猪牛兔鸡鸭类,第三类为山地牛羊兔猪鸡类。在分类的基础上采用等效系数法,对各地域类型开发潜力进行综合评审。评审结果表明第二种地域类型的开发潜力最大。通过地域类型的分类和开发潜力的评审,认为要加强发展丘陵地带的畜牧业,调整全县的畜禽结构,提高草食动物的比例,充分开发利用草场和植物性蛋白饲料资源。  相似文献   

2.
本文分析了鄂中丘陵地区一个典型农户生态系统的能流途径,人工辅助能的输入结构,各亚系统的能量输入、输出组成和能量流动关系,以及能量转化效率。以70个农户的样本分析研究了投能结构对能效的影响规律。结果表明,当地农户生态系统仍是一种以有机能为主要人工辅助的封闭性较强的能量转化系统;增加人工辅助能,特别是无机能的投入可以增加能量产出。  相似文献   

3.
大熊猫以低营养高纤维的竹子作为主要食物来源,但其消化系统结构保留了肉食动物的特点,不具备消化纤维素的能力,因此肠道菌群对其消化纤维素具有重要意义.为了解不同季节亚成体大熊猫肠道微生物结构的变化及其与肠道纤维素消化能力的内在联系,通过高通量测序技术分析4只亚成体大熊猫肠道细菌和真菌多样性的季节差异,并检测不同季节的肠道纤维素酶活性.结果发现不同季节亚成体大熊猫肠道细菌、真菌结构和丰富度存在较大差异.复杂的肠道微生物组成,特别是优势细菌结构主要决定了亚成体大熊猫消化利用纤维素的能力.冬季(2月)肠道微生物结构较复杂,微生物丰富度也相对较高,细菌的优势度高于其他季节.秋季(11月)和冬季(2月),亚成体大熊猫的纤维素酶活性较高,冬季纤维素酶活性约为其他季节的5倍.亚成体大熊猫的纤维素酶活与其肠道优势细菌Streptococcus丰度的季节变化具有相似的趋势,相关性系数为0.582,是大熊猫分解利用纤维素的重要贡献者.因此,亚成体大熊猫不同季节的肠道微生物结构演变对其纤维素消化具有重要影响.(图3表6参28)  相似文献   

4.
美国杏李园主要害虫与天敌类群间相关性分析   总被引:3,自引:0,他引:3  
应用典范相关分析方法研究了美国杏李园丰要害虫与天敌间的相互关系,在未受干扰的自生园中.害虫亚系统与天敌亚系统间第一典范相关系数达到显著水平,天敌亚系统中瓢虫类、草蛉类与主要害虫蚜虫类,螨类的数量变动规律一致.而蜘蛛类与主要害虫的数最关系不密切,化防园内主要害虫与天敌间的典范相关系数均未达显著永平,这表明未受干扰的自生园和生防园内,害虫与天敌亚系统间存在着有效的数量反馈机制,天敌对害虫具有一定的自然抑制作用,而化防园内,害虫与天敌间的数量反馈机制因农药干扰而失调,生态平衡受破坏.自生园和生防园害虫与天敌主要类群间具正相关关系.害虫亚系统中,蚜虫类贡献最大,其次为山楂叶螨和李小食心虫:天敌亚系统中蜘蛛和瓢虫贡献最大,其次为瓢虫类和草蛉类,草蛉类贡献最小.说明蜘蛛类、瓢虫类与主要害虫的数量变动规律一致.而草蛉类与美国杏李园主要害虫的数量关系不密切.  相似文献   

5.
基于能值理论与方法,通过实地调研、访谈咨询和查阅文献,搜集研究所需的相关数据,构建丹霞山旅游生态系统能量分析结构图和能值指标体系。从遗产地母系统和景区、乡村旅游亚系统两个层面,从生态、社会和经济3个角度,对丹霞山旅游生态系统的自然资产、生态服务、经济功能和社会效益等主要能值指标进行分析,并将丹霞山的能值研究结果,与其他方法研究丹霞山的研究结果、与其他地区的能值研究结果进行比较。结果表明,丹霞山世界自然遗产地拥有的砂砾岩自然资产总能值为1.94×10~(43) sej,生物多样性总能值为6.09×10~(27) sej,二者合计的总能值——货币价值为4.25×1031 yuan($)。同时,2016年丹霞山世界自然遗产地的生态服务总能值为2.61×1020 sej·a~(-1),社会教育总能值为4.27×10~(21) sej·a~(-1)。得益于得天独厚的自然资源优势,丹霞山景区旅游亚系统社会经济投入强度较低,其能值自给率和能值经济效益分别是乡村旅游亚系统的45倍和4倍。以餐饮和民宿为主的乡村旅游亚系统的人力投入是景区旅游的3倍多的同时,污染物排放环境压力是景区的81倍。丹霞山旅游生态系统、景区旅游亚系统和乡村旅游亚系统的能值可持续ESI指数分别为10.83、4.05和0.02,3个系统分属不同旅游经济发展状态。最后从遗产地、景区、乡村和政府4个方面提出丹霞山旅游生态系统的优化建议,如遗产地方面,扩大遗产地接待游客的面积;景区旅游方面,重点打造科普旅游品牌;乡村旅游方面,规范管理引领美丽乡村建设;地方政府方面,加强环境整治和开发引导。  相似文献   

6.
芒苞草(Achanthoclamys bracteata P.C.Kao)是分布于横断山区局部狭小区域的一种单型科植物,在指示植物系统进化和地理环境变迁中具有十分重要的作用和地位.对四川省道孚县鲜水河流域的两个芒苞草分布地点(麦粒山和亚卓山)进行了群落学特征和土壤学研究.芒苞草生境群落类型为温性干旱河谷灌丛和草地,上接亚高山云冷杉针叶林.麦粒山芒苞草生境为毛莲蒿-矮嵩草-芒苞草群落;而亚卓山灌丛草地类型为川滇蔷薇-毛莲蒿-西南野古草-芒苞草群落,亚卓山草地则以西南野古草、直芒草、金发藓等为优势种.物种多样性指数以灌丛最高,亚卓山草地物种多样性在中海拔处出现极小值,海拔越高,芒苞草单株重量越轻,中海拔位置处的地上地下生物量比值(2.06±0.17)最大.土壤元素含量以铝和铁最丰富,而磷和钾的含量分别为(8 873.5±1463.3)mg kg-1和(431.1±180.4)mg kg-1,比该区域的平均值低.芒苞草多生长在有岩石出露的地方,在道孚县的分布区域局限在鲜水河河谷地带.芒苞草强烈的生境选择作用以及河谷地带强度较大的人为活动,是威胁芒苞草生存的主要因素.图5表3参24  相似文献   

7.
钛磁铁矿异相Fenton法对亚甲基蓝模拟废水的脱色研究   总被引:1,自引:0,他引:1  
本研究运用紫外可见光谱、傅立叶转换红外光谱和13C核磁共振谱以及水相中溶解性有机碳和固相上元素碳分析等技术对钛磁铁矿异相Fenton法脱色业甲基蓝的过程进行了研究.实验结果表明:钛磁铁矿异相Fenton法对亚甲基蓝的脱色速率远高于磁铁矿;在钛磁铁矿异相Fenton法脱色亚甲基蓝过程中,脱除的亚甲基蓝都已被降解,且钛磁铁矿没有发生相变;虽然钛磁铁矿异相Fenton法不能使亚甲基蓝矿化,但亚甲基蓝结构中的苯环已经被打开.  相似文献   

8.
用电子显微镜的负染色技术,对史氏甲烷短杆菌H13( Methanobrevibactersmithii H13)、嗜热甲酸甲烷杆菌CB12( Methanobacterium thermoformicicum CB12) 、拉布雷甲烷粒菌Z( Methanocorpusculum labreanum Z) 的表面结构观察比较结果表明:史氏甲烷短杆菌H13 和嗜热甲酸甲烷杆菌CB12 的表面层由规则排列的四边形亚单位组成;前者每个亚单位直径为5~7 nm ,亚单位之间的中心距离为5 ~8 nm ,后者亚单位直径为9~12 nm ,亚单位之间的中心距离为11~14 nm .拉布雷甲烷粒菌Z的表面层是条纹和颗粒状或丝状组成的网状结构.每根条纹宽3~4 nm ,条纹之间的距离为6~8 nm .3 株产甲烷细菌的表面层各不相同,其中嗜热甲酸甲烷杆菌CB12 和拉布雷甲烷粒菌Z的表面层结构十分独特,明显不同于已报道的产甲烷细菌和古细菌的表面层结构.  相似文献   

9.
熊蜂(Bombus spp.)因其独特形态特征及生物学特性成为农业生产中重要传粉昆虫,在维持自然及农业生态系统平衡发挥重要作用。近年来,熊蜂多样性呈减少趋势,农药不合理施用为重要因素之一。本文基于农药对熊蜂的毒理学研究现状,系统整理了熊蜂急性致死和慢性亚致死毒理研究方法,围绕农药对熊蜂的急性毒性,亚致死剂量农药对熊蜂精子活性及体温调节等生理发育,颜色分辨及学习记忆行为、肠道微生物结构及解毒因子等方面影响展开综述,对研究中存在的问题和未来研究方向进行了思考和展望,旨在为农药的科学使用、生物环境安全评估及熊蜂多样性保护提供参考。  相似文献   

10.
通过对中国1 458个自然保护区综合科学考察报告和总体规划等资料的分析,对中国自然保护区内自然遗迹的就地保护状况进行了调查。调查结果显示,将自然遗迹列为主要保护对象的保护区共220个,所保护的自然遗迹涵盖了3大类12类35个亚类,占总大类的100%,总类的92%,总亚类的76%,自然遗迹就地保护网络体系已初步形成。同时就我国自然保护区内自然遗迹保护存在的发展速度缓慢、空间布局不均衡、类型结构不合理和认识程度不够等问题进行探讨,并提出相应的对策建议。  相似文献   

11.
Two issues in ecological network theory are: (1) how to construct an ecological network model and (2) how do entire networks (as opposed to individual species) adapt to changing conditions? We present a novel method for constructing an ecological network model for the food web of southeastern Lake Michigan (USA) and we identify changes in key system properties that are large relative to their uncertainty as this ecological network adapts from one time point to a second time point in response to multiple perturbations. To construct our food web for southeastern Lake Michigan, we followed the list of seven recommendations outlined in Cohen et al. [Cohen, J.E., et al., 1993. Improving food webs. Ecology 74, 252–258] for improving food webs. We explored two inter-related extensions of hierarchical system theory with our food web; the first one was that subsystems react to perturbations independently in the short-term and the second one was that a system's properties change at a slower rate than its subsystems’ properties. We used Shannon's equations to provide quantitative versions of the basic food web properties: number of prey, number of predators, number of feeding links, and connectance (or density). We then compared these properties between the two time-periods by developing distributions of each property for each time period that took uncertainty about the property into account. We compared these distributions, and concluded that non-overlapping distributions indicated changes in these properties that were large relative to their uncertainty. Two subsystems were identified within our food web system structure (p < 0.001). One subsystem had more non-overlapping distributions in food web properties between Time 1 and Time 2 than the other subsystem. The overall system had all overlapping distributions in food web properties between Time 1 and Time 2. These results supported both extensions of hierarchical systems theory. Interestingly, the subsystem with more non-overlapping distributions in food web properties was the subsystem that contained primarily benthic taxa, contrary to expectations that the identified major perturbations (lower phosphorous inputs and invasive species) would more greatly affect the subsystem containing primarily pelagic taxa. Future food-web research should employ rigorous statistical analysis and incorporate uncertainty in food web properties for a better understanding of how ecological networks adapt.  相似文献   

12.
饲料是养殖动物的主要食物来源,饲料中的持久性有机污染物(POPs)能够在养殖动物体内蓄积,从而影响动物源性食品安全,对人体健康构成潜在的危害.目前有关饲料中二英类等传统POPs的研究已较为深入,而饲料中新型POPs的污染也逐渐引起人们的关注.本文综述了现有文献关于饲料中多溴二苯醚(PBDEs)、六溴环十二烷(HBCD...  相似文献   

13.
利用Excel2000电子数据表格软件提供的线性规划对畜禽的饲料配方寻求最优解,具有科学、运算速度快、增减原料随意和数据修改容易等优点,可以省去手工计算饲料配方的繁琐,与研制出来的专家系统饲料配方软件及相关计算机设计饲料配方的程序相比,该方法无须要求使用者首先购买这些软件和程序,只要用户购买电脑并安装上Excel7000电子数据表格软件后即可运用线性规划设计饲料配方。  相似文献   

14.
Zovi D  Stastny M  Battisti A  Larsson S 《Ecology》2008,89(5):1388-1398
Herbivore populations may become adapted to the defenses of their local hosts, but the traits that maximize host exploitation may also carry ecological costs. We investigated the patterns and costs of local adaptation in the pine processionary moth, Thaumetopoea pityocampa, to its host plants, Pinus nigra and P. sylvestris. The two hosts differ in needle toughness, a major feeding impediment for leaf-eating insects. We observed a west-to-east gradient of increasing progeny size in the Italian Alps, matching the pattern in toughness of their respective local host plant. Eastern populations that feed on the native P. nigra with tough needles had larger eggs, and neonate larvae with larger head capsules, than western populations that feed on the native P. sylvestris and the introduced P. nigra with softer foliage. In a reciprocal transfer experiment that involved the eastern-most and the western-most populations of T. pityocampa from this region, and excluded natural enemies, we found evidence for local adaptation to the host plant. Specifically, larvae from the western population only performed well when raised on their local hosts with soft needles, and they suffered near-complete mortality on the tough foliage at the eastern site. In contrast, larvae from the eastern population survived equally well at both sites. Local adaptation involved a trade-off between progeny size and the number of offspring. We hypothesized that an additional cost, imposed by natural enemies, may be associated with increased egg size: we also observed a west-to-east gradient of increased egg parasitism. We tested this hypothesis in a common garden by exposing eggs of both populations to parasitism by two native egg parasitoids, Ooencyrtus pityocampae and Baryscapus servadeii. The eastern population suffered a higher level of parasitoid attack by O. pityocampae than the western population, and performance of hatched adults of both parasitoids was enhanced in large eggs. Thus, increased neonate quality (larger eggs yielding larger larvae) confers an advantage on tough foliage but incurs the ecological cost of increased parasitism, which may constrain further adaptation by this herbivore.  相似文献   

15.
Gridded weather data were evaluated as sources of forcing variables for biophysical models of intertidal animal body temperature with model results obtained using local weather station data serving as the baseline of comparison. The objective of the study was to determine which gridded data are sufficient to capture observed patterns of thermal stress. Three coastal sites in western North America were included in this analysis: Boiler Bay, Oregon; Bodega Bay, California; and Pacific Grove, California. The gridded data with the highest spatial resolution, the 32-km North American Regional Reanalysis (NARR) and the 38-km Climate Forecasting System Reanalysis (CFSR), predicted daily maximum intertidal animal temperature most similarly to the local weather Station data. Time step size was important for variables that change rapidly throughout the day, such as solar radiation. There were site-based differences in the ability of the model to predict daily maximum intertidal animal temperature, with the gridded data predictions being the closest to local weather station predictions in Boiler Bay, Oregon. In a review of gridded data used as part of ecological studies, there was broad use of the data across subject areas and ecosystems so the recent improvements in the spatial (from 2 degrees to 32 km) and temporal scales (from 6 hours to 1 hour) of gridded data will further add to the applicability within the ecological community particularly for mechanistic studies.  相似文献   

16.
This paper examines agropastoral transhumance in 12 sampled villages on the southeast Tibetan Plateau. By analysing trends in this indigenous livelihood system and examining causes and potential consequences, we conclude that Tibetan agropastoral transhumance is a fragile system extremely vulnerable to external impacts. Within the context of China's rapid development and globalisation, this agricultural heritage is changing rapidly, as is most saliently reflected in herd size and structure, movement patterns, relative economic importance of pastoral activities and the relations between pastoralism and crop cultivation. Immediate causes of changes are local changes in livestock management objectives, land uses and labour availability, which are driven by more fundamental changes of environmental, political, socioeconomic, technological and cultural profiles, from local to global scales. Changes in local livelihood systems can have multifaceted and profound political, socioeconomic, cultural and ecological consequences, in both constructive and destructive terms. Policy-makers and/or project designers must have a holistic perspective so as to integrate multiple objectives of promoting sustainable socioeconomic development, preserving biological and cultural diversities and maintaining the environmentally stable balance of human society, animal population and ecosystem that has existed in the area for centuries.  相似文献   

17.
Myers JA  Harms KE 《Ecology》2011,92(3):676-686
Two prominent mechanisms proposed to structure biodiversity are niche-based ecological filtering and chance arrival of propagules from the species pool. Seed arrival is hypothesized to play a particularly strong role in high-diversity plant communities with large potential species pools and many rare species, but few studies have explored how seed arrival and local ecological filters interactively assemble species-rich communities in space and time. We experimentally manipulated seed arrival and multiple ecological filters in high-diversity, herbaceous-dominated groundcover communities in longleaf pine savannas, which contain the highest small-scale species richness in North America (up to > 40 species/m2). We tested three hypotheses: (1) local communities constitute relatively open-membership assemblages, in which increased seed arrival from the species pool strongly increases species richness; (2) ecological filters imposed by local fire intensity and soil moisture influence recruitment and richness of immigrating species; and (3) ecological filters increase similarity in the composition of immigrating species. In a two-year factorial field experiment, we manipulated local fire intensity by increasing pre-fire fuel loads, soil moisture using rain shelters and irrigation, and seed arrival by adding seeds from the local species pool. Seed arrival increased species richness regardless of fire intensity and soil moisture but interacted with both ecological filters to influence community assembly. High-intensity fire decreased richness of resident species, suggesting an important abiotic filter. In contrast, high-intensity fire increased recruitment and richness of immigrating species, presumably by decreasing effects of other ecological filters (competition and resource limitation) in postfire environments. Drought decreased recruitment and richness of immigrating species, whereas wet soil conditions increased recruitment but decreased or had little effect on richness. Moreover, some ecological filters (wet soil conditions and, to a lesser extent, high-intensity fire) increased similarity in the composition of immigrating species, illustrating conditions that influence deterministic community assembly in species-rich communities. Our experiment provides insights into how dispersal-assembly mechanisms may interact with niche-assembly mechanisms in space (spatial variation in disturbance) and time (temporal variation in resource availability) to structure high-diversity communities and can help guide conservation of threatened longleaf pine ecosystems in the face of habitat fragmentation and environmental change.  相似文献   

18.
祁连山自然保护区生态承载力分析与评价   总被引:7,自引:0,他引:7  
以层次分析法和模糊模式识别为基础,建立生态承载力综合评价模型,重点分析祁连山自然保护区森林、草地和农田3种受人类活动干扰最强烈的生态系统的生态承载力和生态荷载,在此基础上进一步分析整个保护区的总体生态承载力和生态荷载。结果显示,祁连山区域生态系统已经受到人类活动的强烈干扰,生态荷载总体处于严重超载状态。但区域生态系统内部各子系统之间以及生态荷载的空间分布存在差异。其中,森林子系统和草地子系统属于严重超载,农田子系统属于中度超载;在总体生态荷载的空间分布上,西北部地区比东南部地区超载更为严重;就各子系统的生态荷载状况而言,森林子系统和草地子系统的超载程度均表现为东南部地区略低于西北部地区,但农田子系统东南部地区超载程度高于西北部地区。  相似文献   

19.
The use of byproducts of the food industry as feedstuffs for animals has become a significant conflict for agriculture. Public regulations concerning the improvement of nutrient recycling and economic production with less financial support, on one hand, and the avoidance of all risks for human and animal health, on the other hand, are seen to affect agriculture practice. In this paper, information is presented about the quantities and quality of byproducts of the food industry used as feedstuffs. Also the nutritional and economical value of meat meal is discussed including ecological aspects. Other use or the disposal of products high in their nutritional value should, in the future, be no alternatives to the use as feed for animals, when risks are carefully controlled, because of the necessity for a sustainable agriculture and economy.  相似文献   

20.
Understanding complex systems is essential to ensure their conservation and effective management. Models commonly support understanding of complex ecological systems and, by extension, their conservation. Modeling, however, is largely a social process constrained by individuals’ mental models (i.e., a small-scale internal model of how a part of the world works based on knowledge, experience, values, beliefs, and assumptions) and system complexity. To account for both system complexity and the diversity of knowledge of complex systems, we devised a novel way to develop a shared qualitative complex system model. We disaggregated a system (carbonate coral reefs) into smaller subsystem modules that each represented a functioning unit, about which an individual is likely to have more comprehensive knowledge. This modular approach allowed us to elicit an individual mental model of a defined subsystem for which the individuals had a higher level of confidence in their knowledge of the relationships between variables. The challenge then was to bring these subsystem models together to form a complete, shared model of the entire system, which we attempted through 4 phases: develop the system framework and subsystem modules; develop the individual mental model elicitation methods; elicit the mental models; and identify and isolate differences for exploration and identify similarities to cocreate a shared qualitative model. The shared qualitative model provides opportunities to develop a quantitative model to understand and predict complex system change.  相似文献   

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