云南不同气候带农业气候资源变化特征研究

为分析全省平均以及各气候带光能、热量、水分资源的时空变化特征,使用云南115站及6个气候带代表站1961—2018年的气候要素计算各地农业气候资源统计量。结果表明,光能资源变化以减少趋势为主,出现显著突变,各气候带太阳辐射变化可能会引起云南太阳辐射高低值中心发生变化,2009年以来辐射明显增加可能会导致太阳辐射出现新的变化趋势和突变点;热量资源一致显著增加,喜凉及喜温作物的活动积温、积温持续时间及无霜期长度均显著增加,并且呈现初日提前、终日推后的趋势,对作物生长有利;水分资源总体呈现减少趋势,尤其21世纪以来下降趋势明显,亚热带地区暖干化现象突出,干旱风险等级较高。     

Acoustic evaluation of the vertical distribution of dwarf ayu Plecoglossus altivelis altivelis in Lake Biwa

SUMMARY: The vertical distribution of dwarf ayu Plecoglossus altivelis altivelis in the pelagic waters of Lake Biwa was evaluated from June to September in 1995–97 from eight acoustic surveys using a quantitative echosounder. In each survey, echoes from a depth range of 3 m to the sea bottom were collected at a station every 2.7 s for 24 h together with measurements of vertical profiles of water temperature and chlorophyll-a. The ayu's echoes were identified using an underwater video camera. The ayu were observed near the maximum chlorophyll-a depth and above the thermocline. Their density was highest at depths of 4–11 m with 2–4 individuals/m ³ and was almost zero below 20 m. Echo signs were recorded as having a frequent duration of more than 1 h at night, whereas were of a shorter duration in the day. The fish stay in the epilimnion during the day without any clear vertical migration, but are distributed more uniformly at night. The advantages of remaining in the epilimnion are discussed in terms of food availability and predator avoidance.     

Factors Affecting the use of Dreissena polymorpha as a Bioindicator: the PCB Pollution in Lake Como (N. Italy)

The aim of this study was to assess the PCB pollutionof the South-Western branch of Lake Como by using thezebra mussel (Dreissena polymorpha) as abioindicator since its recent reintroduction. Someenvironmental and physiological variables influencingaccumulation processes of organochlorine compounds inDreissena were investigated because climaticfactors may affect life cycle, reproductive stage andage. PCB levels were highest in the soft tissues ofDreissena close to the industrialized area ofComo (2298 ng g^-1 of lipids) and slowly decrease goingnorth, reaching approximately half this value at theclosing section of the lake branch. Nonetheless, thePCB concentrations are well below the dangerous levelsfor the aquatic environment.     

我国中央山系东段演化及其对黄河河道及东平湖的影响

根据2603a有史记载以来黄河河道变迁和春秋以来东平湖演变历史，本文提出我国中央山系东段碰撞和松弛导致的地势上升和下降是影响黄河河道变迁和东平湖演变的重要因素。山系碰撞上升造成黄河河道向北西迁移，东平湖湿地北漫；山系松弛下降导致黄河河道向东南迁移，东平湖南泛。     

双子叶子叶出土植物根-茎转变区的特征和分类

利用偏光显微镜镜检等手段,研究了14科22个属、种的双子叶植物的根-茎转变区,提出较全面的有关概念并发现数种异于一般的转变方式,根据该区的存在部位和长短以及结构特点,提出几套新的分类法:1.根型、根-下胚轴和下胚轴型;2.剧变型及缓变型;3.正常型和异常型。     

Issues and Some Strategies of Sustainable Development of Black Soil Resources in Black Soil Zone in Northeast China

黑土资源是世界的稀缺资源,黑土带的水土流失、环境污染、土地流转、土地退化问题成为黑土资源可持续发展的障碍。根据实地调研结合资料,分析了东北黑土带土地资源可持续发展的主要问题;提出了黑土资源的可持续发展对策,即:加强农业发展规划;保护黑土区耕地,农耕技术上改进,加强农田基本建设等。     

太湖麇鹿一雌哺乳三仔的行为剖析

苏州西山太湖麋鹿园的麋鹿一雌同时哺乳三仔的行为，仔鹿共表现出四种吮乳模式：即一仔鹿在哺乳雌鹿后侧吮乳，二仔鹿在哺乳雌鹿腹部左侧吮乳；一仔鹿在哺乳雌鹿后侧吮乳，二仔鹿在哺乳雌鹿腹部右侧吮乳；一仔鹿在哺乳雌鹿后侧吮乳，二仔鹿在哺乳雌鹿腹部左右侧各一头吮乳；三仔鹿分别立于哺乳雌鹿的后侧、左侧和胸腹下方吮乳。太湖麋鹿一雌哺乳三仔的特殊行为的表现，既取决于鹿群的生活空间和鹿群的密度，又与哺乳雌鹿摄入的饲料质量相关联，同时也与仔鹿一时饥饿而又无法寻找到自己的母亲哺乳有关。     

浙江淳安新安江开发公司封山育林效益研究

浙江省淳安县新安江开发公司所属16个国营林场22475.53hm~3荒山迹地,封山育林30年,现有天然次生林总蓄积量135万m~3,年总生长率8.07％,活立木直接经济价值2.25亿元。到1987年止公司已获中间利用净收入2135万元。近20年累计天然次生林比无林地多涵蓄水10亿m~3,每年进入水库的泥沙量减少80％,对调节水库水源、延长发电年限、纯洁水质都起到良好作用。公司长期实施的5项管护技术,把封山育林提高到科学经营水平,在千岛湖区成功地建立了森林生态屏障。     

甘肃白银地区生态区域分异及其恢复途径初步探讨

依据白银地区的水-热及土壤基质等自然环境状况及生态恢复需要,划分白银地区为冷温微润、冷温微干、微温微干、微温干旱、微温极干5个生物气候及生态恢复区、10个恢复亚区.根据各恢复区的基本特征、退化现状和退化主导因子的分异,探讨了区域生态恢复途径.     

皖西白鹅羽区皮肤组织结构的研究及其绒被分析

本试验针对皖西白鹅绒皮制裘生产中的问题，观察研究了１２０、１５０、２００、２４０、３６０、５４０六个日龄组计４８只皖西白鹅绒皮的组织结构。结果表明，各日龄组皮肤结构差异不甚明显。其真皮内羽肌发达，羽囊粗大，脂肪组织含量多，纤维层薄，纤维成分少，排列疏松。２４０日龄以后纤维层增厚。