北京地区木本春季物候特征与生物学特性的关系

植物物候是植物生活史中的重要性状,也是指示气候与自然环境变化的重要指标,现已成为全球变化领域的研究热点之一。传统物候研究多假设物候由气候因素决定,如气温、降水、光照等,并主要从植物物候的年际变化角度探讨了气候因素对物候特征的影响。然而,不同物种的物候存在较大差异表明植物物候还与自身生物学特性（如系统发育和功能性状）有关,但植物生物学特性如何影响植物物候仍缺乏深入研究。基于北京地区44种木本植物1965-2018年的展叶始期和开花始期观测资料,以展叶始期和开花始期的3类物候特征（平均物候期、物候对温度的响应敏感度和物候期的积温需求）为例,探究植物物候特征与系统发育和功能性状的关系。首先,利用系统发育信号Blomberg’s K和进化模型检验植物物候特征是否具有系统发育保守性,并通过系统发育信号表征曲线直观表达植物物候特征的进化模式;之后,利用广义估计方程分析植物生活型、传粉型与物候特征的关系,以揭示不同植物的资源利用方式及生存策略的差异。研究发现：（1）除展叶始期的温度敏感度外,其余物候特征的进化均受随机遗传漂变和自然选择力的共同作用,可推断物候特征具有系统发育保守性,即亲缘关系越近的物种物候特征越相似。（2）开花始期的系统发育信号强度比展叶始期更大,表明繁殖物候的系统发育可能比生长物候更保守。（3）植物展叶始期及其积温需求与生活型密切相关。灌木比乔木的展叶时间早、积温需求少。植物开花始期与传粉型相关,风媒植物开花显著早于虫媒植物。研究成果有助于深入理解物候变化的生物学机制,对于丰富物候学的理论研究有重要意义,同时对植物保护也具有重要的指导价值。     

East versus West: contrasts in phenological patterns?

Aim To examine whether change in the timing of a large number of phenological events and their response to temperature differs between trophic levels during the period 1988–2008. Location In the vicinity of Kazan, Tatarstan Republic, Russia (55°45′ N, 49°08′ E). Methods Observations of the dates of first events of 22 plant phases, 8 insect phases, 3 herpetofauna phases and 26 migrant bird phases were examined using regression to assess changes over time and response to temperature. Differences between trophic levels were assessed using ANOVA. Results In comparison to studies from western Europe, relatively few phenological series (15) revealed a significant advance over time, but a much larger number (37), including all the herpetofauna and nearly all the plants, showed a response to temperature. Trends in birds were, on average, twice as great as those for plants, but plants had a significantly greater temperature response. Over the study period local temperatures had not risen significantly but some phenological change was still evident. Main conclusions Phenological change has been less marked in the eastern edge of Europe than in western and central Europe. This is compatible with a lack of significant local warming during the study period. A large number of species show strong responses to temperature so will be expected to advance if/when local temperatures do increase. In contrast to results from elsewhere in Europe, early events were not the most temperature responsive, suggesting local adaptation preventing precocious behaviour and the consequent dangers of sub‐zero temperatures.     

中国北方主产地苹果冷热积累变化及其对始花期的影响

开展气候变化背景下苹果冷热积累变化及其对始花期的影响研究,对指导苹果种植及生产具有重要意义。本研究选取山东福山、山西万荣、甘肃西峰和新疆阿克苏代表中国北方苹果主产地,利用1996—2018年红富士苹果的始花期观测资料和逐时气温数据,采用动态模型、生长度小时模型分别计算逐日冷积累量(CP)和热积累量(GDH),并利用偏最小二乘回归法,对逐日冷、热积累量和各地苹果始花期进行相关分析,以明确各地苹果冷、热积累起止日期和积累量,以及冷、热积累期内温度变化对始花期的影响规律。结果表明: 我国北方主产地苹果冷积累时段集中于10月1日前后至2月中下旬或3月中旬,积累量为74.1～89.3 CP;热积累时段集中于1月下旬前后至始花期,积累量为4010～5770 GDH。西峰和阿克苏冷积累期内平均气温每升高1 ℃,冷积累量将分别增加3.8和5.0 CP;各地热积累期内平均气温每升高1 ℃,热积累量将增加725～967 GDH。与冷积累期内温度变化的影响效应相比,热积累期内温度变化主控我国北方主产地苹果始花期,且气候变暖总体有利于冷积累期内平均气温较低地区的苹果开花和生产。     

Changes of the Flowering Time of Trees in Spring by Climate Change in Seoul,South Korea

Flowering onset has attracted much attention in ecological research as an important indicator of climate change. Generally, warmer temperatures advance flowering onset. The effect of climate warming on flowering onset is more pronounced in spring because the difference between atmospheric and water temperatures creates more rapid convection than in other seasons. We analyzed the correlation between 73 species of spring woody plants in Hongneung Arboretum in Seoul, South Korea and the spring minimum temperature and average precipitation over the past 50 years (1968–2018). The spring minimum temperature and average precipitation have increased over the past 50 years, resulting in the advance of the first flowing date (FFD) in all 73 species by 8.5 days on average. A comparison of FFD changes over time by dividing the survey period into three time periods confirmed the advance of the FFD in 50 species (68% of investigated species) by 11.1 days on average in both Period 2 (1999–2008) and Period 3 (2009–2018) relative to Period 1 (1968–1975). Additionally, a delay of the FFD by 3.2 days on average was observed in 8 species. The FFD of Lonicera chrysantha (Caprifoliaceae) advanced by over 40 days and was highly correlated with the increased spring minimum temperature. Analysis of the sensitivity of plant responses to climate change revealed that a temperature rise of 1°C was associated with an FFD advance of 1.2 days in all species. The species that was most sensitive to temperature change was Spiraea pubescens for. leiocarpa (Rosaceae), whose FFD advanced by 4.7 days per 1°C temperature rise. Each increase in precipitation by 1 mm was found to result in a 0.1-day advance of the FFD of all species. Prunus tomentosa (Rosaceae) was the most sensitive species, that advanced by 2.6 days for each 1 mm increase in precipitation. Thus, for all species, the FFD was more sensitive to the change in temperature than in precipitation. Assuming that the current greenhouse gas (GHGs) emission levels or atmospheric CO₂ concentration is maintained, Seoul’s spring minimum temperature is projected to rise by 2.7°C over the next 50 years. Accordingly, considering only the global temperature change, the mean FFD of the study’s 73 species is projected to advance by an additional 3.4 days.     

Breeding timed to maximize reproductive success for a migratory songbird: the importance of phenological asynchrony

Phenological advances and trophic mismatches are frequently reported ecological consequences of climate warming. Trophic mismatches occur when phenological responses to environmental conditions differ among trophic levels such that the timing of resource demand by consumers becomes decoupled from supply. We used 25 years of demographic measurements of a migratory songbird (the black‐throated blue warbler Setophaga caerulescens) to compare its breeding phenology to the phenology of both its caterpillar prey and the foliage on which caterpillars feed. Caterpillar biomass in this forest did not show a predictable seasonal pulse. Nest initiation by warblers in this northern hardwood forest was therefore not timed to coincide with a peak in food availability for nestlings. Nonetheless, timing of first clutches was strongly associated with spring leaf expansion (slope ± SE = 0.56 ± 0.08 days per day of change in leaf phenology, R² = 0.66). Warblers adjusted the timing of breeding to early springs mainly by shortening the interval between arrival and clutch initiation, but this likely has limits because recent early springs are approaching the relatively inflexible dates when birds arrive on the breeding grounds. Although the timing of first nests did not match 1:1 with leaf‐out phenology, the adjustments in breeding time maximized mean annual reproductive success. Nest predation had the greatest effect on annual reproductive success, but the ability of nesting warblers to appropriately track leaf phenology accounted for effects on annual reproductive success comparable to the influence of variation in caterpillar abundance and conspecific density. Nesting phenology in black‐throated blue warblers was generally well matched to the timing of leaf‐out, even though the match was not 1:1. Without measurements of reproductive success, these unequal phenological shifts might otherwise have been interpreted as having negative ecological consequences.     

西双版纳地区鞘花的繁殖物候特征及影响因素

桑寄生植物作为关键种和关键性食物资源在生态系统中扮演着重要角色,其鞘花的繁殖物候特征不仅会影响自身的繁殖适合度而且还会影响依赖于其获取食物资源的动物。为了解鞘花的繁殖物候特征及其影响因素,探究其与寄主植物和种子散布者之间的相互作用关系。该研究以西双版纳地区分布的鞘花为对象,通过定期观测鞘花和其寄主植物木荷的繁殖物候,测量它们的生物学特性和温湿度等环境因子,并分析鞘花在个体水平和种群水平上的繁殖物候特征以及寄主植物和温湿度对其繁殖物候的影响。结果表明:(1)鞘花的开花物候属于集中大量开花模式,整个种群的花期和果期的持续时间分别约为20 d和72 d,花期和果期的同步性指数都较高,6月中旬鞘花果实被取食的数量和速率最大,之后逐渐降低。(2)鞘花的始花期与木荷的始花期相关性较高,花期和果期与木荷的繁殖物候基本重叠。(3)每月开花和果熟的个体数量与同期和前一个月的平均温度和相对湿度的相关关系均不显著。总之,桑寄生植物的繁殖物候特征可能受到较多因素的影响,若想全面了解半寄生植物的繁殖物候特征,就要综合考虑生物和非生物等多种因子的共同作用。     

Changes in first flowering dates and flowering duration of 232 plant species on the island of Guernsey

Climate change has affected plant phenology; increasing temperatures are associated with advancing first flowering dates. The impact on flowering duration, however, has rarely been studied. In this study, we analysed first flowering dates and flowering durations from a 27 year dataset of weekly flower observations on 232 plant species from the island of Guernsey in the English Channel. The aim of this study was to explore variation in trends and relationships between first flowering dates, flowering duration and temperature. We specifically looked for evidence that traits, such as life forms and phylogenetic groups, explained variation in sensitivity of first flowering and flowering duration among species. Overall trends revealed significantly earlier flowering over time, by an average of 5.2 days decade^?1 since 1985. A highly significant shortening of flowering duration was observed by an average of 10 days decade^?1. Correlations between first flowering, flowering duration and year varied between different species, traits and flowering periods. Significant differences among traits were observed for first flowering and to a lesser degree for flowering duration. Overall, in comparison to first flowering, more species had significant trends in flowering duration. Temperature relationships revealed large differences in strength and direction of response. 55% of the species revealed a significant negative relationship of first flowering dates and temperature. In contrast, only 19% of flowering durations had a significant negative temperature relationship. The advance in first flowering date together with a shortening of flowering duration suggests potentially serious impacts on pollinators, which might pose a major threat to biodiversity, agriculture and horticulture. Human health, in terms of pollen allergies, however, might benefit from a shortening of specific plant pollen seasons.     

A generalist brood parasite modifies use of a host in response to reproductive success

Avian obligate brood parasites, which rely solely on hosts to raise their young, should choose the highest quality hosts to maximize reproductive output. Brown-headed cowbirds (Molothrus ater) are extreme host generalists, yet female cowbirds could use information based on past reproductive outcomes to make egg-laying decisions thus minimizing fitness costs associated with parasitizing low-quality hosts. We use a long-term (21 years) nest-box study of a single host, the prothonotary warbler (Protonotaria citrea), to show that local cowbird reproductive success, but not host reproductive success, was positively correlated with the probability of parasitism the following year. Experimental manipulations of cowbird success corroborated that female cowbirds make future decisions about which hosts to use based on information pertaining to past cowbird success, both within and between years. The within-year pattern, in particular, points to local cowbird females selecting hosts based on past reproductive outcomes. This, coupled with high site fidelity of female cowbirds between years, points to information use, rather than cowbird natal returns alone, increasing parasitism rates on highly productive sites between years.     

Phylogenetic and climatic constraints drive flowering phenological patterns in a subtropical nature reserve

Aims Exploring flowering patterns and detecting processes are essential when probing into the nature of reproductive traits during the life history and the interactions among different evolutionary clades. Such patterns are believed to be influenced by many factors, but quantifying these impacts at the community-level remains poorly understood.Methods We investigated the flowering patterns based on long-term herbarium records in a given area from subtropical forest regions in southern China. We obtained 5258 herbarium voucher specimens collected from the Dinghushan National Nature Reserve (DNNR) belonging to 166 families, 943 genera and 2059 species and examined the month when each species was flowering during the period 1920–2007.Important findings The results showed that plants flowered sequentially almost throughout the whole year, showing the characteristics of subtropical evergreen broad-leaved forests. Flowering spectrums of the entire flora and the four life forms exhibited a clear unimodality that is probably typical of subtropical forest communities. Flowering patterns of the DNNR were positively correlated with mean rainfall, mean air temperature and mean sunshine duration. Median flowering dates of the 38 large species-rich families ranged from early April to late August; 25 families exhibited significant unimodal distribution patterns, whereas the remaining families were unclear or bimodal. Median flowering dates of the 10 most species-rich genera ranged from middle May to later July. While the results are consistent with climatic factors playing a general role in flowering patterns, median flowering dates varied significantly among species-rich families and genera, suggesting that phylogenies could provide specific constraints in subtropical forests.     

西安和宝鸡木本植物花期物候变化及温度敏感度对比

植物物候是指示生态系统对气候变化响应的重要证据。已有研究多基于代表性站点的物候观测数据研究物候特征及其对气候变化的响应规律。同一气候区内,不同站点的物候变化及对温度变化响应的敏感度是否一致仍需深入探讨。本文选择同属于暖温带湿润区汾渭平原气候区的西安和宝鸡为研究区,利用"中国物候观测网"在两个站点21个共有物种的开花始期和开花末期数据,比较了1987—2016年两站点各植物花期物候变化特征及其对温度变化响应的敏感度差异。结果表明,西安和宝鸡各物种的开花始期和开花末期均以提前趋势为主。大部分物种开花始期在西安的提前趋势(平均趋势-0.57 d/a)明显强于在宝鸡的提前趋势(平均趋势-0.29 d/a),但开花末期趋势差异不显著。除紫薇和迎春的敏感度差异较大外,其他物种开花始期和开花末期的温度敏感度在两站点间非常接近,无显著差异。由此可见,在同一气候区的不同站点,因增温幅度不同,植物的始花期变化存在较大差异,不能用单站点的物候变化反映整个气候区的物候变化。但同一植物在单站点的温度敏感度可以较好的反映同一气候区其他站点的植物物候-气候关系。本文研究结果可为利用有限站点的物候观测数据分析区域物候...     

Selection on personality in a songbird affects maternal hormone levels tuned to its effect on timing of reproduction

The increase or decrease in yolk androgens over the laying sequence of a clutch in birds may mitigate or enhance, respectively, the disadvantage of the last-hatched chicks, providing a potentially adaptive tool to adjust brood size to food conditions. This variation may involve a genetic component on which Darwinian selection can act. We found that two lines of a wild bird species selected for bold and shy personalities show, respectively, increased and decreased androgen concentrations over the laying sequence. The line showing the increase laid earlier in the season, when food conditions are normally sufficient to raise the whole brood. The line showing the decrease laid later, when food is normally scarce, which may facilitate brood reduction. The results indicate a correlated response in maternal hormone transfer to genetic selection on personality, which relates to ecological conditions.     

Comparison of the genetic determinism of two key phenological traits,flowering and maturity dates,in three Prunus species: peach,apricot and sweet cherry

The present study investigates the genetic determinism of flowering and maturity dates, two traits highly affected by global climate change. Flowering and maturity dates were evaluated on five progenies from three Prunus species, peach, apricot and sweet cherry, during 3–8 years. Quantitative trait locus (QTL) detection was performed separately for each year and also by integrating data from all years together. High heritability estimates were obtained for flowering and maturity dates. Several QTLs for flowering and maturity dates were highly stable, detected each year of evaluation, suggesting that they were not affected by climatic variations. For flowering date, major QTLs were detected on linkage groups (LG) 4 for apricot and sweet cherry and on LG6 for peach. QTLs were identified on LG2, LG3, LG4 and LG7 for the three species. For maturity date, a major QTL was detected on LG4 in the three species. Using the peach genome sequence data, candidate genes underlying the major QTLs on LG4 and LG6 were investigated and key genes were identified. Our results provide a basis for the identification of genes involved in flowering and maturity dates that could be used to develop cultivar ideotypes adapted to future climatic conditions.     

Nitrogen enrichment weakens ecosystem stability through decreased species asynchrony and population stability in a temperate grassland

Biodiversity generally promotes ecosystem stability. To assess whether the diversity–stability relationship observed under ambient nitrogen (N) conditions still holds under N enriched conditions, we designed a 6‐year field experiment to test whether the magnitude and frequency of N enrichment affects ecosystem stability and its relationship with species diversity in a temperate grassland. Results of this experiment showed that the frequency of N addition had no effect on either the temporal stability of ecosystem and population or the relationship between diversity and stability. Nitrogen addition decreased ecosystem stability significantly through decreases in species asynchrony and population stability. Species richness was positively associated with ecosystem stability, but no significant relationship between diversity and the residuals of ecosystem stability was detected after controlling for the effects of the magnitude of N addition, suggesting collinearity between the effects of N addition and species richness on ecosystem stability, with the former prevailing over the latter. Both population stability and the residuals of population stability after controlling for the effects of the magnitude of N addition were positively associated with ecosystem stability, indicating that the stabilizing effects of component populations were still present after N enrichment. Our study supports the theory predicting that the effects of environmental factors on ecosystem functioning are stronger than those of biodiversity. Understanding such mechanisms is important and urgent to protect biodiversity in mediating ecosystem functioning and services in the face of global changes.     

Complementarity effects through dietary mixing enhance the performance of a generalist insect herbivore

The ontogenetic niche concept predicts that resource use depends on an organism’s developmental stage. This concept has been investigated primarily in animals that show differing resource use strategies as juveniles and as adults, such as amphibians. We studied resource use and performance in the grasshopper Chorthippus parallelus (Orthoptera, Acrididae) provided with food plant mixtures of either one, three or eight plant species throughout their development. C. parallelus survival and fecundity was highest in the food plant mixture with eight plant species and lowest in the treatments where only one single plant species was offered as food. C. parallelus’ consumption throughout its ontogeny depended on sex, and feeding on different plant species was dependent on a grasshopper’s developmental stage. To depict grasshopper foraging in food plant mixtures compared to foraging on single plant species, we introduce the term “relative forage total” (RFT) based on an approach used in biodiversity research by Loreau and Hector (Nature 413:548–274, 2001). RFT of grasshoppers in food plant mixtures was always higher than what would have been expected from foraging in monocultures. The increase in food consumption was due to an overall increase in feeding on plant species in mixtures compared to consumption of the same species offered as a single diet. Thus we argue that grasshopper foraging exhibits complementarity effects. Our results reinforce the necessity to consider development-related changes in insect herbivore feeding. Thorough information on the feeding ontogeny of insect herbivores could not only elucidate their nutritional ecology but also help to shed light on their functional role in plant communities. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Effects of within-tree flowering asynchrony on the dynamics of seed and wasp production in an Australian fig species

Abstract. Within-tree flowering asynchrony in figs, which may allow pollinating wasps to avoid the risks of dispersal in inclement conditions, has been predicted as a trait to be favoured in highly seasonal environments. Comparisons of such asynchronous figs with better-known species that exhibit within-tree synchrony might also be expected to reveal differences in the outcome of the conflict between pollinator wasp and fig seed production, and the dynamics of non-pollinating wasps. This paper presents data on wasp and seed production in Ficus rubiginosa Desf. ex Vent., an asynchronous species that occurs in the highly seasonal environment of south-eastern Australia. In contrast to recent studies of figs showing within-tree flowering synchrony, syconium size was the main determinant of wasp and seed production in F. rubiginosa . Non-pollinating wasps were highly prevalent but occurred in low numbers and appeared to have relatively little impact on pollinator wasp or fig seed production. Data on flower positions revealed that non-pollinating wasps occurred almost exclusively in the outer layer of flowers, while pollinators were more abundant in the inner flower layer, which may represent an area of enemy-free space. The ratio of seeds to female pollinator wasps, an index of fig sex allocation, was more seed-biased than in several New World fig species that exhibit within-tree synchrony. This last result supports the idea that within-tree fruiting asynchrony permits a degree of self-pollination in F. rubiginosa .     

Influence of hatching asynchrony and within-brood parental investment on size, condition, and immunocompetence in nestling red-billed choughs

Studies of hatching asynchrony have rarely assessed the effect of parental investment strategies on the development of intra-brood hierarchies using indicators of nestling quality. The influence of hatching asynchrony and other variables related to parental investment on immunocompetence was evaluated measuring T-cell mediated immune response in broods of red-billed choughs ( Pyrrhocorax pyrrhocorax ), a large long-living passerine with a pronounced sexual size dimorphism. The results showed that T-cell mediated immune response depends on parental effects as shown by the differences between broods on hatching asynchrony. Male nestlings were both heavier and larger than female nestlings, but there was no effect of hatching order on these traits, nor on sex differences in immunocompetence. Differential investment strategy in relation to laying order did not favour older offspring or either of the sexes. Successful reproduction in this species might be so unpredictable and infrequent that strategies of parental investment in the brood could have evolved to attempt to maximize the survival of all nestlings by avoiding within-brood hierachies of size, body condition, and immunocompetence.  © 2008 The Linnean Society of London, Biological Journal of the Linnean Society , 2008, 94 , 675–684.