杭州湾滩涂Na元素含量对植物多样性和优势度的影响

钠元素是滩涂湿地土壤盐分的最主要成分。利用样方法调查了杭州湾滩涂湿地的植物多样性及其分布,以及土壤钠含量对植物多样性和优势度的影响,用相关回归方法对数据进行分析处理。结果表明：（1）海塘内的物种多样性要高于海塘外,有11种植物,优势植物是芦苇（Phragmites australis）和互花米草（Spartina alterniflora）,且互花米草的优势度要高于芦苇;但是在海塘外的自然滩涂,则只出现3种植物,主要优势植物是互花米草和海三棱藤草（Scirpus xmariqueter）,芦苇则较为少见。在海塘外的海三棱藤草-互花米草混合群落中,海三棱藤草的优势度要高于互花米草。（2）物种丰富度指数（Margalef指数）和物种多样性（Simpson指数）指数均与土壤钠含量呈极显著负相关关系,通过回归分析得回归方程分别为y（Margalef指数）=-0．05x＋1．608（R^2=0．732,P〈0．01,n=10）,y（Simpson指数）=-0．038x＋1．214（R^2=0．926,P〈0．01,n=10）。（3）海塘内互花米草的重要值与土壤钠含量呈极显著正相关,y=0．033x-0．007（R^2=0．802,P〈0．01,n=10）;而芦苇重要值则与其呈极显著负相关,y=-0．013x＋0．419（R^2=0．607,P〈0．01,n=10）。在海塘外的混合群落中,互花米草和海三棱藤草的重要值与土壤钠含量之间没有明显的相关关系。（4）随着（海塘）围垦时间的延长,其物种多样性呈现增大的趋势,中生植物更为丰富,而盐生植物逐渐萎缩。     

中国森林的地下碳分配

通过收集国内33个森林样地的土壤呼吸和年凋落物量数据，分析中国森林地下碳分配（TBCA）模式。结果表明，中国森林土壤呼吸年通量与年凋落物量呈显著的线性相关（R^2=0．3319，P=0．000），其中成熟林土壤呼吸与年凋落物量间呈显著的线性相关（R^2=0．3245，P=0．004），但未成熟林土壤呼吸与年凋落物量间的线性相关不显著（R^2=0．3485，P=0．092）。中国森林的地下碳分配变化范围1．460～25．100tChm^-2a^-1，平均值为9．217tChm^-2a^-1；中国森林的TBCA与年均气温相关关系不显著（P=0．196），但与年均降水量则呈显著正相关（R=0．480，P=0．021）。中国森林TBCA和凋落物对土壤呼吸的平均贡献分别为74．2％和25．8％；中国森林TBCA对土壤呼吸的贡献随土壤呼吸增大而增大，而凋落物对土壤呼吸的贡献则随土壤呼吸的增大而降低。     

葎草雌雄植株开花物候和花器官对干旱的响应差异

摘要：以蓓草（Humulusscandens）为实验材料,在控制土壤水分的条件下探究干旱对雌雄异株植物开花物候和花器官形态的影响,结果表明：干旱胁迫将导致蓰草雌雄种群花期提前．花期持续时间延长,雌花将比雄花提早开放;干旱胁迫下雄花的花序轴长、花序轴直径和花药粒径长均分别显著减小24．81％。29．07％和5．14％（P〈0．001,P=0．003,P=0．024）,花粉活力和花粉含量显著下降：干旱胁迫导致雌花的花序轴长、柱头长度和花序的平均花数量显著增大9．78％,70．62％和57．04％（P=0．039．P〈0．001．P〈0．001）;干旱胁迫下种子粒径长、种子粒径宽、种子单粒重和种子千粒重分别显著下降12．12％、12．59％、43．43％和15．38％（显著度水平均为P〈0．001）;干旱胁迫下雌雄植株的地上部分生物量均显著降低（P=0．002,P=0．020）,且雌株的生殖投入在干旱胁迫下显著高于雄株（P=0．049）。研究结果表明了蓰草雌雄植株开花物候及花器官对干旱的响应明显不同。与雄株相比．雌株在干旱胁迫下增加了生物量向生殖器官的分配,从而最大程度地减轻胁迫对其繁殖能力的影响。     

华北平原罗布麻种群生殖分株数量特征及变化规律

通过大样本取样调查,研究了华北平原罗布麻种群生殖分株的数量特征和生殖分配规律．结果表明,在籽粒完熟期,罗布麻种群单个生殖分株重为10．38±7．78g,蒴果生物量和蒴果数分别为1．57±1．59g和7．60±6．56个;种子生物量和种子数分别为0．34±0．33g和582．3±558．7个;生殖分配Ⅰ和生殖分配Ⅱ分别为12．98±7．94和2．75±1．69％．蒴果和种子形成分别需要分株积累1．42和1．77g以上的生物量．蒴果生物量、葫果数、种子生物量、种子数分别与分株总生物量呈极显著的（P〈0．01）线性正相关关系;蒴果数、种子数与茎叶生物量分配呈极显著的（P〈0．01）线性负相关关系;生殖分配Ⅰ、生殖分配Ⅱ和叶生物量分配呈极显著的（P〈0．01）线性负相关关系．单葫果的重量、种子重、种子数、种子毛重、胎座重分别和葫果的长度呈极显著（P〈0．01）的幂函数正相关关系．罗布麻种群生殖分株同时具有同速和异速2种不同增减过程的表型可塑性调节．     

气候变化对鄱阳湖白鹤越冬种群数量变化的影响

分析了1983—2011年鄱阳湖国家级自然保护区越冬白鹤种群数量的年际变化趋势,检验了白鹤种群动态与繁殖地和越冬地气候变化的相关性,气候变量包括月平均气温、月平均最高气温、月平均最低气温和月降水量。研究结果表明,鄱阳湖国家级自然保护区内的白鹤年最大数量平均为(2 130±153)只,呈显著地线性增长趋势(R2=0.454,F=22.441,df=28,P=0.000),但年际波动较大。在越冬地,越冬当年10月、11月、12月的气候变量与白鹤种群数量没有显著的相关性,但越冬初期10月份和越冬后期翌年3月份的气温变量与第4年、第5年、第6年及第7年的白鹤种群数量存在显著的正相关,表明越冬地气候对白鹤种群大小的影响存在时滞效应。越冬初期和末期可能是白鹤补充能量的关键阶段,而且越冬初期的气候可能也与冬季食物的数量或质量相关,因此这两个阶段的适宜气温可能有利于个体尤其是幼鹤的存活,使更多的个体参加繁殖,由于白鹤的性成熟年龄在3—5a,因此其对白鹤种群增长的有利影响会在3a以后表现出来。白鹤种群数量变化与繁殖地繁殖期的降水量没有显著的相关性,而与7月份的气温变量存在显著的正相关。多元线性回归分析结果表明,6a前的10月份平均最低温度、2a前的10月最高温度及5a前的10月平均气温是白鹤种群数量变化的显著预测因子,共同解释了鄱阳湖国家级自然保护区白鹤种群数量变化的74.8%(F=23.807,df=27,P=0.000)。     

瑞士西部农田周围生态保留带中小型兽类种群结构特征及数量动态的初步研究

为了评价生态保留带对小型兽类种群的影响,2003年7月至2004年6月在瑞士西部Salavaux,chevmux和Montbrelloz 3个地区采用标志重捕方法对小型兽类种群进行了研究。在3个生态保留带中,共发现6种1206只小型兽类,其中普通田鼠、小林姬鼠、中麝晌捕获数量多。普通田鼠为优势种。普通田鼠的种群数量在生态保留带间有差异,但具有相同的季节性波动趋势,一般种群数量随着植被覆盖度和食物丰富度的增加,春季末开始出现增加,仲夏达到最高水平。种群中雌雄个体年龄结构之间有明显的差异,成体和亚成体的数量比幼体多,雄性亚成体的数量比雌性多,雌性成体数量比雄性多（X^2=44．09,df=10,P〈0．001,N=203）。普通田鼠种群中雌雄个体体重之间有明显的差异,雄性的体重比雌性大（t一检验：t=5．011,df=162,P〈0．05,N=213）。种群性比之间有明显的月间变化,雌性的捕获次数比雄性大。普通田鼠只在短距离范围内活动,在生态保留带中的巢区为350～400m^2,雌雄个体的巢区大小之间没有显著性差异。     

布氏田鼠种群繁殖特征研究

越冬田鼠每年可繁殖3胎,第1胎幼仔生于4月下旬到6月上旬,第2胎幼仔生于5月中旬到7月上旬,第3胎幼仔生于6月中旬到7月下旬。种群上升年份(1987)各胎幼仔出生高峰比1988年的提前10天左右。1987年越冬鼠第1胎集中,如4月下半月,1987年怀孕率为100%,而1988年只有44.44%。6月上半月以前越冬鼠为种群繁殖的主体,而后被当年生鼠所取代。从4月下半月到9月上半月共出生4批同龄群。K₁和K₂组生长发育旺盛,当年就参加种群繁殖,可怀孕1—3胎。K₃组生长发育较慢,当年并不性成熟,越冬后性成熟成为种群越冬鼠的主体。K₄出生晚,数量少,很少能度过漫长寒冷的冬季而成为种群的无用或潜在的繁殖力量。本文还发现越冬鼠的平均胎仔数显著高于当年鼠：种群上升年份越冬鼠平均胎仔数高于种群下降年份,而当年生鼠的平均胎仔数年度间则没有显著性差异。     

应用实验种群生命表评价巴氏新小绥螨对西花蓟马的控制能力

以西花蓟马Frankliniella occidentalis（Pergande）（Thysanoptera,Thripidae）一龄若虫为猎物组建巴氏新小绥螨Neoseiulus barkeri（Hughes）（Acari：Phytoseiidae）实验种群生命表,获得净生殖力Ro=27．37,世代平均历期T=22．17天,内禀增长率rm=0．15,周限增长率λ=1．16,种群倍增所需时间t=4．64天等参数。将获得参数值与西花蓟马的相关参数值进行比较,巴氏新小绥螨瞬间增长率大于西花蓟马的瞬间增长率（0．14）,雌成螨日取食7～12头西花蓟马一龄若虫,表明巴氏新小绥螨可以作为控制西花蓟马种群数量的有效天敌。     

鄱阳湖国家级自然保护区东方白鹳(Ciconia boyciana)种群数量变化与气候的关系

该研究分析了1985—2011年鄱阳湖国家级自然保护区东方白鹳(Ciconia boyciana)越冬种群数量的年际变化趋势,探究了越冬地气候条件对其种群数量变化的影响。结果表明,1985—2011年,保护区东方白鹳种群数量为(1 340±178)只,呈显著线性增长趋势,但年际波动较大。种群数量与越冬当年11月份的平均最低气温显著正相关(r=0.554,P=0.003,n=27),越冬初期较低的温度可能影响东方白鹳选择鄱阳湖作为长期越冬地的决策,而增加对长江中、下游其他湿地的利用。同时,越冬地气候条件对种群数量的影响存在显著的时滞效应。越冬初期以及越冬后期的气温变量与2~9年后的种群数量显著正相关。尤其是越冬初期10月份的气温变量与2~5年后的种群数量变化极显著相关,越冬后期2月和3月的气温变量分别与8年后和3年后的种数数量极显著正相关。多元线性回归分析结果表明,2年前的10月平均最高温度、2年前的3月平均最高气温、4年前的10月平均最高温度、4年前的3月平均气温是东方白鹳种群数量变化的显著预测变量,共同解释了种群数量年际变化的79.2%(R2=0.792,F=20.901,df=26,P=0.000)。越冬初期和末期可能是个体迁飞后补充能量和迁飞前积累能量的关键阶段,适宜的气温有利于成体的能量积累和幼体的存活,且东方白鹳性成熟年龄为2~6年,因此,越冬地气候条件对其种群增长的影响将会在2年后体现。     

在不同条件下人工饲养大鲵的呼吸特征

于2004年4月25日～5月15日在河南卢氏县大鲵（Andrias davidianus）养殖场对大鲵肺呼吸活动的方式进行了详细观察,发现与已报道的方式不同。大鲵的肺呼吸采取了肺腔贮存气体、间歇式浮出水面、以1次呼气和2次吸气、咽气过程构成的换气方式来适应水栖生活,其肺呼吸活动方式属于四程式呼吸。大鲵在白天休息状态下的肺换气频次受气温、水温和大气压等气候因子变化的影响,换气频次的多少与水温的高低变化呈正相关（R=0．917,P〈0．01）,与大气压的高低变化呈负相关（R=-0．954．P〈0．01）。     

绿盲蝽越冬卵的耐寒能力

近年来,随着转基因棉花的大面积推广,绿盲蝽成为了我国棉花和果树生产的重要害虫。为了阐明绿盲蝽越冬生态适应性,研究了绿盲蝽卵在越冬过程中的耐寒力变化,测定了卵内生化物质的含量,结果表明:绿盲蝽越冬卵低温存活力呈现出明显的月份变化,在-10℃、-20℃处理下,绿盲蝽的越冬卵的半致死时间从大到小的顺序依次为:1月>2月>12月>3月>4月,在-30℃处理下从大到小的顺序依次为:1月>12月>3月>2月>4月。在极端低温(-20℃)下1、2、3、4和5 d后,4月份保护卵死亡率明显低于相同处理下的4月份裸露卵的死亡率,枣枝中的越冬卵死亡率分别为4.32%、5.36%、5.42%、6.79%和7.63%,剥离出来的越冬卵死亡率分别为46.06%、51.84%、54.59%、63.07%和74.41%。人工滞育卵的耐寒性强于正常发育卵的耐寒性,弱于自然越冬过程中滞育卵的耐寒性。冷驯化可以显著提高绿盲蝽越冬卵的低温存活力,在0℃冷驯化20 min后,越冬卵的低温(-20℃、100 h)死亡率显著降低,冷驯化40 min后,低温死亡率趋于平稳,均在37%左右。越冬卵体内物质呈明显的季节性变化,越冬卵越冬期的含水量显著高于越冬后,其中1月份最高(43.98%),4月份达到最低(38.79%)。越冬卵体内总脂肪含量在整个越冬过程中逐渐降低,从12月份的38.24%,降低到4月份的27.08%。蛋白质和糖的含量均是先降低后升高,其中蛋白质从12月份的78.77μg/mg,降低到1月份的59.80μg/mg,然后又逐渐升高至4月份的73.62μg/mg,体内总糖含量由12月份的39.60μg/mg降低至1月份的21.17μg/mg,然后又逐渐升高至4月份的35.10μg/mg。绿盲蝽越冬卵的耐寒力随着月份的变化而变化,在整个越冬期间表现出较强的抗寒性,能够抵御冬季低温,而其越冬场所的保护作用增加了其对于冬季严寒的适应性。     

滇西南稻区白背飞虱种群特征及其关键影响因子

为明确滇西南沧源县稻区白背飞虱Sogatella furcifera的种群发生特征及其影响因子,于2010-2019年通过灯诱监测和田间调查的方法,分析沧源县白背飞虱的越冬种群、灯诱种群及田间种群发生特征,并对白背飞虱种群数量的影响因素进行相关性分析.结果表明:(1)白背飞虱以成、若虫在再生稻、落粒稻上越冬,越冬虫量最...     

Using weather indices to predict survival of winter wheat in a cool temperate environment

Seven years of winter survival data for winter wheat ( Triticum aestivum L.) were collected on a loam soil located on the Central Experimental Farm at Ottawa, Ontario (45 degrees 23'N, 75 degrees 43'W). The site was low-lying and subject to frequent winter flooding and ice-sheet formation. Two cultivars, a soft white and a hard red winter wheat, were planted in September. Crop establishment was measured in late fall and the percentage survival was measured in April of the following year. Meteorological data, which were available from the nearby weather site, were used to develop a large set of monthly weather indices that were felt to be important for winter survival. The objective of the study was to use genetic selection algorithms and artificial neural networks to select a subset of critical weather factors and topographic features and to model winter survival. The six weather indices selected were the total rain depth for December (mm), the total rain depth for February (mm), the number of days of the month with snow on the ground for January, the extreme minimum observed daily air temperature for March ( degrees C), the number of days of the month with snow on the ground for March, and the number of days of April with a daily maximum air temperature greater than 0 degrees C. It was found 89% of the variation in winter survival could be explained by these six weather indices, the cultivar, elevation and plot location.     

Developmental mortality increases sex‐ratio bias of a size‐dimorphic bark beetle

1. Given sexual size dimorphism, differential mortality owing to body size can lead to sex‐biased mortality, proximately biasing sex ratios. This mechanism may apply to mountain pine beetles, Dendroctonus ponderosae Hopkins, which typically have female‐biased adult populations (2 : 1) with females larger than males. Smaller males could be more susceptible to stresses than larger females as developing beetles overwinter and populations experience high mortality. 2. Survival of naturally‐established mountain pine beetles during the juvenile stage and the resulting adult sex ratios and body sizes (volume) were studied. Three treatments were applied to vary survival in logs cut from trees containing broods of mountain pine beetles. Logs were removed from the forest either in early winter, or in spring after overwintering below snow or after overwintering above snow. Upon removal, logs were placed at room temperature to allow beetles to complete development under similar conditions. 3. Compared with beetles from logs removed in early winter, mortality was higher and the sex ratio was more female‐biased in overwintering logs. The bias increased with overwinter mortality. However, sex ratios were female‐biased even in early winter, so additional mechanisms, other than overwintering mortality, contributed to the sex‐ratio bias. Body volume varied little relative to sex‐biased mortality, suggesting other size‐independent causes of male‐biased mortality. 4. Overwintering mortality is considered a major determinant of mountain pine beetle population dynamics. The disproportionate survival of females, who initiate colonisation of live pine trees, may affect population dynamics in ways that have not been previously considered.     

Overwintering stress of Vaccinium vitis-idaea in the absence of snow cover

A snow manipulation experiment aimed to assess risks of direct freezing injury, freeze-induced dehydration and winter desiccation in the absence of snow cover on lingonberry (Vaccinium vitis-idaea). Frames with sheet-plastic sides and removable lids were used in this experiment for two purposes: to prevent accumulation of snow in mid-winter and to provide extra heat during early spring. Leaves were analyzed for frost hardiness, tissue water content and osmotic concentrations, and photoinhibition (Fv/Fm) during the period from the 10th of February to the 7th of April. The natural snow accumulation was low indicated by a minor difference in minimum temperatures between the frame treatment and naturally snow-covered plots. The heating effect of the frames started gradually at the end of February along with increasing solar elevation angles, and was highest at the beginning of April. Frost hardiness peaked in March as a consequence of cold periods, but it was practically lost by the beginning of April. Tissue water content decreased gradually at first, becoming greatly decreased later due to the extra heat. In accordance, the tissue osmotic concentrations increased first gradually, followed by a dramatic increase. Photoinhibition increased uniformly with increasing solar radiation, but at the end showed a sharp increment within a few days, obviously also indicating the effect of heating. It was concluded that neither lethal freezing stress nor significant freeze-induced dehydration occurred during the experiment. However, plants that overwintered without snow suffered from severe winter desiccation injuries due to the combination of solar heat and frozen soil. Although the desiccation stress was possibly a lethal factor, it was preceded by long-term and continued photoinhibition. It was concluded that during overwintering, chamaephyte species may suffer from both freezing and winter desiccation in the absence of protecting snow cover. However, during mild winters provided by climatic change scenarios, the risk of winter desiccation will be more probable. In relation to the future climate, it was concluded that winter desiccation and photoinhibition may develop gradually during a snowless winter and would, even if they did not reach a lethal level by themselves, possibly reduce frost hardiness.     

Seasonal changes in serum thyroid hormone levels of the feral brown bullhead, Ictalurus nebulosus Lesueur

Seasonal changes in serum L-thyroxine (T4) and triiodo-L-thyronine (T3) concentrations were measured in a feral population of brown bullheads, Ictalurus nebulosus . Serum T4 was elevated in mid April concomitant with the onset of gonadal recrudescence and the increase in ambient temperatures from the winter level. Thereafter, serum T4 levels were constant throughout the late spring and summer (except for a significant lowering in levels associated with the spawning and early postspawning period), declining to a low overwintering level by mid December. Serum T3 levels increased in April, and apart from a significant decrease in July associated with the postspawning period, rose progressively until August, after which levels declined progressively to reach overwintering levels again by mid December. Between mid April and mid May serum T4/T3 ratios fell from the high values found in fish during the winter months. Apart from variations associated with the fluctuations of T4 and T3 concentrations in the spawning and early postspawning periods, serum T4/T3 ratios remained at a low level throughout the summer and early autumn months, and rose again in October to the overwintering levels. The circannual cycles are discussed in relation to the possible role of the thyroid hormone in gonadal maturation and metabolism in this species.     

Seasonal Rhythms of Body Temperature in the Free‐Ranging Raccoon Dog (Nyctereutes procyonoides) with Special Emphasis on Winter Sleep

The raccoon dog (Nyctereutes procyonoides) is the only canid with passive overwintering in areas with cold winters, but the depth and rhythmicity of wintertime hypothermia in the wild raccoon dog are unknown. To study the seasonal rhythms of body temperature (T_b), seven free‐ranging animals were captured and implanted with intra‐abdominal T_b loggers and radio‐tracked during years 2004–2006. The average size of the home ranges was 306±26 ha, and the average 24 h T_b was 38.0±<0.01°C during the snow‐free period (May–November). The highest and lowest T_b were usually recorded around midnight (21∶00–02∶00 h) and between 05∶00–11∶00 h, respectively, and the range of the 24 h oscillations was 1.2±0.01°C. The animals lost approximately 43±6% of body mass in winter (December–April), when the average size of the home ranges was 372±108 ha. During the 2–9‐wk periods of passivity in January–March, the average 24 h T_b decreased by 1.4–2.1°C compared to the snow‐free period. The raccoon dogs were hypothermic for 5 h in the morning (06∶00–11∶00 h), whereas the highest T_b values were recorded between 16∶00–23∶00 h. The range of the 24 h oscillations increased by approximately 0.6°C, and the rhythmicity was more pronounced than in the snow‐free period. The ambient temperature and depth of snow cover were important determinants of the seasonal T_b rhythms. The overwintering strategy of the raccoon dog resembled the patterns of winter sleep in bears and badgers, but the wintertime passivity of the species was more intermittent and the decrease in the T_b less pronounced.     

雪被去除对川西高山冷杉林冬季土壤微生物生物量碳氮和可培养微生物数量的影响

为了解气候变暖情景下雪被减少对冬季土壤微生物特征的影响,采用人工遮雪的方法,研究了雪被去除对原始冷杉林土壤微生物生物量和可培养微生物数量的影响.结果表明:雪被去除显著影响土壤微生物生物量碳(MBC)和氮(MBN)以及可培养细菌和真菌数量,但土壤微生物在雪被覆盖不同阶段具有不同的响应特征.在雪被去除处理下,土壤有机层MBC和MBN在雪被形成初期和雪被融化前期显著降低,而在雪被覆盖期和雪被融化后期显著增加;在雪被形成初期至雪被覆盖期,可培养细菌数量都显著降低,但可培养真菌数量都显著增加.雪被融化后,雪被去除显著降低土壤有机层MBC和可培养真菌数量,显著增加可培养细菌数量,对MBN无显著影响.矿质土壤层MBC、MBN和可培养微生物数量在雪被去除下的变化趋势与土壤有机层基本一致,但波动较小.雪被去除还改变了川西高山冷杉林冬季土壤微生物类群比,提高了土壤可培养真菌数量的冬季优势.     

Seasonal abundance and activity of the hard tick Haemaphysalis longicornis (Acari: Ixodidae) in North China

Seasonal abundance and activity of all the three post-embryogenic stages of Haemaphysalis longicornis, both feeding and free-living phases, were evaluated over a period of 2 years, from February 2008 to January 2010, in North China. Feeding ticks were removed weekly from head and ears of domestic sheep and the attachment sites of this tick were assessed coinstantaneously; free-living ticks were collected weekly in four habitat types by flag-dragging. The results suggested that H. longicornis mainly resides in shrubs and completes one generation per year with population attrition between stages. Infestation of nymphs was detected from March to September with highest peak between late April and early May; adults were detected from April to September with highest peak between late June and July, and an overwintering male population was found during late September to March; infestation of larvae was observed from June to October and peaked between middle August and early September. Most of this tick (91%) attached to head and ears of hosts. Additionally, we captured rodents from April to September 2008, but only a negligible number of nymphs were detected. This result suggested that rodents are not the principal hosts for this tick in the study area.