多效唑对琯溪蜜柚枝梢生长和越冬期叶片糖、水分状态的影响

本试验探讨了不同浓度多效唑(PP333)对琯溪蜜抽枝梢生长和越冬期叶片淀粉、可溶性糖含量、束缚水/自由水比值的影响.结果表明,多效唑处理能提高越冬期叶片可溶性糖含量,增大束缚水/自由水比值,降低淀粉含量;多效唑处理使新梢长度、节间长度明显受抑制,新梢粗度增加,且随着使用浓度的增大作用增强.     

光周期对中华通草蛉自然越冬成虫及实验种群幼虫耐寒能力的影响

【目的】滞育诱导期进行短光照处理可影响昆虫耐寒性。为明确光周期对中华通草蛉Chrysoperla sinica (Tjeder)耐寒性的影响, 针对中华通草蛉滞育解除过程及非滞育虫态的耐寒性进行了一系列研究。【方法】测定了中华通草蛉自然越冬成虫的过冷却点（supercooling point, SCP）以及长光周期（15L∶9D）和短光周期（9L∶15D）条件下自然越冬成虫在滞育解除过程中在-12℃下的死亡率, 并测定了室内长、 短两种光周期下实验种群2龄和3龄幼虫的过冷却点（SCP）、 结冰点（freezing point, FP）以及-7℃下的死亡率。【结果】中华通草蛉12月份的自然越冬成虫SCP集中在-10~-14℃之间。SCP低于-12℃的个体占43.70%, 且-12℃处理1 d死亡率为62.00%。-12℃处理1 d条件下的长、 短光周期处理自然越冬成虫, 除处理0 d外, 长光周期处理死亡率均高于短光周期处理的, 且在处理15 （P=0.012）, 20 （P=0.01）和25 d （P=0.001）差异显著。中华通草蛉试验种群相同龄期幼虫在短光周期下的SCP和FP均高于长光周期下, 但差异不显著(P>0.05); 但在-7℃下, 2龄幼虫短光周期下的低温死亡率为67.00%±4.04%, 显著低于长光周期下的低温死亡率（78.00%±1.33%）（P=0.011）, 3龄幼虫短光周期条件下低温死亡率为24.33%±1.33%, 显著低于长光周期下的低温死亡率（53.00%±3.46%）（P=0.002）。【结论】中华通草蛉为结冰敏感型, 诱导滞育的短光照处理可提高其幼虫期及滞育解除过程中成虫的耐寒能力。     

中华秋沙鸭越冬行为时间分配及日活动节律

2007年12月-2008年1月和2008年11-12月,在江西省境内4条主要河流及其支流对中华秋沙鸭(Mergus squamatus)越冬期的各种行为活动节律及时间分配进行了实地调查研究。结果表明:中华秋沙鸭越冬期的主要行为有取食、游泳、理羽、静息、睡眠、游戏、飞行和观察。其中取食、游泳、理羽、静息呈明显的节律性变化,且取食与静息呈相反的节律变化;睡眠、飞行、游戏和观察没有明显的节律性变化。取食在7:00-8:00、10:00-11:00、12:00-13:00有明显的峰值,峰值平均间隔2.3h,其它时段具相近取食频次,且上午高于下午。睡眠和静息下午发生频次明显高于上午,并呈现节律性变化,对应3个取食高峰表现为低频次。行为时间分配如下:取食(46%),游泳(23%),理羽(9%)、静息和睡眠(各占8%)、飞行(4%)、游戏(2%)和观察(0.5%)。越冬期中华秋沙鸭大量时间用于取食,意图是为了积累能量。相关分析表明:取食与睡眠的发生呈显著负相关(R=-0.73,df=8,P0.05);取食与飞行的发生呈显著正相关(R=0.70,df=8,P0.05);理羽与静息的发生呈极显著正相关(R=0.88,df=8,P0.01);其他各种行为之间无显著相关性。     

Stable Isotopes (δD, δ13C, δ15N) Reveal Associations Among Geographic Location and Condition of Alaskan Northern Pintails

Abstract: Information on spring migration routes, geographic linkages among winter, spring, and breeding locations, and potential geographic effects on arrival body condition of northern pintails (Anas acuta) are currently unknown. Through a combination of stable-isotope measurements of tissues representing different periods of dietary integration and body composition analyses, we examined these linkages for pintails breeding in Alaska, USA. We collected 77 females at 4 locations upon spring arrival. We performed carbon (δ¹³C), nitrogen (δ¹⁵N), and hydrogen (δD) isotope measurements on flight feathers, breast feathers, and whole blood, and we conducted body composition analyses. Inference based on stable-isotope values in pintail tissues suggests that philopatry to Alaska was strong, as most of the collected females had stable-isotope values consistent with the boreal forest of Canada or western Alaska and most spring migrating females had whole-blood values indicating use of a food web in the boreal forest before collection. These patterns highlight the importance of the boreal forest for production and staging of pintails. Breast feather isotope values grown during prealternate molt were variable and covered the currently documented distribution of wintering pintails. Our results indicate associations among specific geographic areas, habitat use, and arrival condition of female pintails settling in Alaska. Females that wintered or staged in coastal habitat (as indicated by elevated δ¹³C values) arrived with less body fat compared to those that we inferred to have wintered or staged on inland freshwater habitat. Those females we inferred to use coastal areas appeared to rely more heavily on agricultural fields for nutrient acquisition (as indicated by elevated δ¹⁵N but low δ¹³C values). Our results provide the first link between low-condition females and inferred use of specific geographic areas before arrival. Conservation on wintering grounds should focus on restoration and protection of wetland complexes that provide adequate natural food resources in proximity to coastal systems that are heavily used by wintering pintails. Conservation efforts should also focus on the boreal forest, not only for pintail, but for other boreal-dependent species such as lesser scaup (Aythya affinis) (JOURNAL OF WILDLIFE MANAGEMENT 72(3):715–725; 2008)     

Migration and wintering strategies in vulnerable Mediterranean Osprey populations

A broad range of migration strategies exist in avian species, and different strategies can occur in different populations of the same species. For the breeding Osprey Pandion haliaetus populations of the Mediterranean, sporadic observations of ringed birds collected in the past suggested variations in migratory and wintering behaviour. We used GPS tracking data from 41 individuals from Corsica, the Balearic Islands and continental Italy to perform the first detailed analysis of the migratory and wintering strategies of these Osprey populations. Ospreys showed heterogeneous migratory behaviour, with 73% of the individuals migrating and the remaining 27% staying all year round at breeding sites. For migratory individuals, an extremely short duration of migration (5.2 ± 2.6 days) was recorded. Mediterranean Ospreys were able to perform long non‐stop flights over the open sea, sometimes overnight. They also performed pre‐ and post‐migratory trips to secondary sites, before or after crossing the sea during both autumn and spring migration. Ospreys spent the winter at temperate latitudes and showed high plasticity in habitat selection, using marine bays, coastal lagoons/marshland and inland freshwater sites along the coasts of different countries of the Mediterranean basin. Movements and home‐range areas were restricted during the wintering season. The short duration of trips and high levels of variability in migratory routes and wintering grounds revealed high behavioural plasticity among individuals, probably promoted by the relatively low seasonal variability in ecological conditions throughout the year in the Mediterranean region, and weak competition for non‐breeding sites. We stress the importance of considering the diversity in migration strategies and the particular ecology of these vulnerable populations, especially in relation to proactive management measures for the species at the scale of the Mediterranean region.     

Meta‐barcoding insights into the spatial and temporal dietary patterns of the threatened Asian Great Bustard (Otis tarda dybowskii) with potential implications for diverging migratory strategies

Food resources are often not sufficient to satisfy the nutritional and energetic requirements during winter conditions at high latitudes. Dietary analysis is a prerequisite to fully understanding the feeding ecology of a species and the nature of trophic interactions. Previous dietary studies of Asian Great Bustard (Otis tarda dybowskii) relied on behavioral observations, resulting in categorization of diet limited to broad taxonomic groupings. Here, we applied a high‐throughput sequencing meta‐barcoding approach to quantify the diet of resident and migratory Asian Great Bustard in three wintering sites during early winter and late winter. We detected 57 unique plant taxa in the bustard diet, among which 15 species were confirmed by a local plant database we generated. Both agricultural and natural foods were detected, indicating a relatively broad dietary niche. Spatiotemporal dietary changes were discovered, revealing diet differences among wintering sites and a general shift toward lower plant diversity later in winter. For the nonmigratory population, we detected a significantly more diverse array of plant species in their diet. We hypothesize that dietary variation between resident and migratory populations could be involved in the recent transition to partial migration in this species, although climate change can not be excluded. Collectively, these results support protecting unharvested grain fields and naturally unplowed lands to help conserve and promote population growth of Asian Great Bustard.     

A new breeding population of Mediterranean Gulls Larus melanocephalus in the species' main wintering area maintains independent spatial dynamics

We studied a newly established breeding population of the range‐expanding Mediterranean Gull Larus melanocephalus in eastern Spain, situated in close proximity to the species' main wintering area. By investigating the origin, population composition and wintering area of the new breeders, we found that recruitment from locally wintering birds was unlikely and that the emerging colonies were probably attracting birds from populations wintering 700–1200 km away in Portugal and southern Spain. Our findings reveal that expanding populations may follow their own dynamics, independently of other populations of the same species, and may consist of different individuals altogether.     

贵州省石阡鸳鸯湖国家湿地公园越冬鸳鸯数量、分布及日行为初探

为了解贵州省石阡鸳鸯湖国家湿地公园越冬鸳鸯Aix galericulata的种群密度、日行为特征及人为干扰对其的影响,于2017年10月—2018年3月,采用直接计数法对鸳鸯数量、性比及人为干扰下的种群密度进行了22次调查。越冬中期,种群数量稳定在755只±17只,性比为1.14∶1,各条河沟的数量之间的差异具有高度统计学意义(X^2=84.041,df=5,P<0.01),即大河、小河与坝坎为鸳鸯分布及活动的主要区域;种群密度与人为干扰次数呈极显著负相关(R=-0.799,n=90,P<0.01),在人为干扰次数为1次±1次的区域,种群密度为42只/hm^2±3只/hm^2～53只/hm^2±14只/hm^2,当人为干扰次数达到7次±3次时,几乎没有鸳鸯活动。同时采用瞬时扫描法对鸳鸯的8种越冬行为进行了34 d(442 h)的观察,共记录各行为136 933次。取食、休息和修整为鸳鸯的主要行为;除了修整,鸳鸯在保育区与非保育区的各行为时间分配差异有高度统计学意义(P<0.01);越冬日行为节律极具规律性,取食高峰在07∶00—08∶00、14∶00—15∶00和17∶00—18∶00;休息高峰在13∶00—14∶00和15∶00—16∶00;飞行高峰在06∶00—07∶00(飞回湖区)和18∶00—19∶00(飞往夜栖地);修整在各时间段发生均较为频繁。