Individualistic responses of bird species to environmental change

We investigated how the population dynamics of the same bird species varied in different environments, and how the population dynamics of different species varied in the same environment, by calculating long-term population trends for 59 insectivorous songbird species in 22 regions or strata of eastern and central North America using data from the North American Breeding Bird Survey. Of the 47 species that occurred in more than one region 77% increased in some regions and declined in others. Of the 22 regions 91% had some species that increased and others that decreased. There were only slightly more significant correlations between strata in species trends and between species for stratum trends than would be expected by chance. Because of nonlinearities in the data, the actual patterns of population fluctuations of the same species in different regions and of different species in the same region were even more heterogeneous than suggested by our analyses of linear trends. We conclude that these bird species respond to spatial and temporal variation in their environment in a very individualistic fashion. These individualistic responses show that the extrapolation of population trends gained from a few local studies to a larger spatial scale, and the use of a few indicator species to monitor the status of a broader community, are suspect.     

Changing gull diet in a changing world: A 150‐year stable isotope (δ13C, δ15N) record from feathers collected in the Pacific Northwest of North America

The world's oceans have undergone significant ecological changes following European colonial expansion and associated industrialization. Seabirds are useful indicators of marine food web structure and can be used to track multidecadal environmental change, potentially reflecting long‐term human impacts. We used stable isotope (δ¹³C, δ¹⁵N) analysis of feathers from glaucous‐winged gulls (Larus glaucescens) in a heavily disturbed region of the northeast Pacific to ask whether diets of this generalist forager changed in response to shifts in food availability over 150 years, and whether any detected change might explain long‐term trends in gull abundance. Sampled feathers came from birds collected between 1860 and 2009 at nesting colonies in the Salish Sea, a transboundary marine system adjacent to Washington, USA and British Columbia, Canada. To determine whether temporal trends in stable isotope ratios might simply reflect changes to baseline environmental values, we also analysed muscle tissue from forage fishes collected in the same region over a multidecadal timeframe. Values of δ¹³C and δ¹⁵N declined since 1860 in both subadult and adult gulls (δ¹³C, ~ 2–6‰; δ¹⁵N, ~4–5‰), indicating that their diet has become less marine over time, and that birds now feed at a lower trophic level than previously. Conversely, forage fish δ¹³C and δ¹⁵N values showed no trends, supporting our conclusion that gull feather values were indicative of declines in marine food availability rather than of baseline environmental change. Gradual declines in feather isotope values are consistent with trends predicted had gulls consumed less fish over time, but were equivocal with respect to whether gulls had switched to a more garbage‐based diet, or one comprising marine invertebrates. Nevertheless, our results suggest a long‐term decrease in diet quality linked to declining fish abundance or other anthropogenic influences, and may help to explain regional population declines in this species and other piscivores.     

When three traits make a line: evolution of phenotypic plasticity and genetic assimilation through linear reaction norms in stochastic environments

Genetic assimilation emerges from selection on phenotypic plasticity. Yet, commonly used quantitative genetics models of linear reaction norms considering intercept and slope as traits do not mimic the full process of genetic assimilation. We argue that intercept–slope reaction norm models are insufficient representations of genetic effects on linear reaction norms and that considering reaction norm intercept as a trait is unfortunate because the definition of this trait relates to a specific environmental value (zero) and confounds genetic effects on reaction norm elevation with genetic effects on environmental perception. Instead, we suggest a model with three traits representing genetic effects that, respectively, (i) are independent of the environment, (ii) alter the sensitivity of the phenotype to the environment and (iii) determine how the organism perceives the environment. The model predicts that, given sufficient additive genetic variation in environmental perception, the environmental value at which reaction norms tend to cross will respond rapidly to selection after an abrupt environmental change, and eventually becomes equal to the new mean environment. This readjustment of the zone of canalization becomes completed without changes in genetic correlations, genetic drift or imposing any fitness costs of maintaining plasticity. The asymptotic evolutionary outcome of this three‐trait linear reaction norm generally entails a lower degree of phenotypic plasticity than the two‐trait model, and maximum expected fitness does not occur at the mean trait values in the population.     

小麦转录因子TaWRKY74-c和TaWRKY74-d基因的克隆及基于生物信息学的功能分析

WRKY基因是近年来研究较为广泛的植物转录因子,目前许多物种中都克隆出WRKY基因。近年来,小麦中也有WRKY基因被克隆,但是由于对WRKY基因生物信息学分析不足,导致研究带有一定的盲目性。本试验以小麦品种扬麦158叶片为材料,分离了2个WRKY基因,分别编码344个和371个氨基酸,与GenBank数据库中的TaWRKY74基因高度同源,命名为TaWRKY74-c和TaWRKY74-d。蛋白质保守结构域分析表明,2个基因都含有1个WRKY保守结构域,属于Ⅲ类WRKY转录因子家族。定量PCR分析表明TaWRKY74-c和TaWRKY74-d在小麦的叶片、花和茎中均表达,且在茎中的表达量最多,在花中的表达量最少。采用Genevestigator转录组分析工具,对基因在331种环境条件(如逆境、病害、激素等刺激)、10个发育时期(如苗期、孕穗期等)和21种组织器官(如根、花、叶等)中的表达进行了分析,结果表明,该基因在小麦不同发育时期和组织器官中都有表达,且在植物遭受低温、病原体侵染等环境因子处理下,表达量发生显著改变,预示可能参与到这些生物学过程中。采用RT-PCR的方法对上述分析结果进行验证,结果表明生物学实验与生物信息学预测的结果一致。本研究将大量小麦转录组的数据应用到WRKY基因功能分析上,深化了对小麦WRKY基因家族成员功能的认识,为今后对该基因的表达分析和功能研究提供了重要线索和方向。     

Environmental DNA enables detection of terrestrial mammals from forest pond water

Terrestrial animals must have frequent contact with water to survive, implying that environmental DNA (eDNA) originating from those animals should be detectable from places containing water in terrestrial ecosystems. Aiming to detect the presence of terrestrial mammals using forest water samples, we applied a set of universal PCR primers (MiMammal, a modified version of fish universal primers) for metabarcoding mammalian eDNA. The versatility of MiMammal primers was tested in silico and by amplifying DNAs extracted from tissues. The results suggested that MiMammal primers are capable of amplifying and distinguishing a diverse group of mammalian species. In addition, analyses of water samples from zoo cages of mammals with known species composition suggested that MiMammal primers could successfully detect mammalian species from water samples in the field. Then, we performed an experiment to detect mammals from natural ecosystems by collecting five 500‐ml water samples from ponds in two cool‐temperate forests in Hokkaido, northern Japan. MiMammal amplicon libraries were constructed using eDNA extracted from water samples, and sequences generated by Illumina MiSeq were subjected to data processing and taxonomic assignment. We thereby detected multiple species of mammals common to the sampling areas, including deer (Cervus nippon), mouse (Mus musculus), vole (Myodes rufocanus), raccoon (Procyon lotor), rat (Rattus norvegicus) and shrew (Sorex unguiculatus). Many previous applications of the eDNA metabarcoding approach have been limited to aquatic/semiaquatic systems, but the results presented here show that the approach is also promising even for forest mammal biodiversity surveys.     

福建省火炬松生长与环境因子的典型相关分析

运用典型相关分析等多元统计方法对福建省火炬松（Pinus taeda Linn.)人工林的生长与环境因子间的相互关系进行分析。结果表明,对地处亚热带的福建省而言,火炬松的生长性状除了与年龄、密度有关外,与年均温、≥10℃积温呈正相关,与年降水量呈负相关,从而为火炬松的栽培区划和生产力评价提供科学依据。     

喀斯特峰丛洼地旱季土壤水分的空间变化及主要影响因子

基于动态监测样地(200 m×40 m)的网格(10 m×10 m)取样,用地统计学方法研究了喀斯特峰丛洼地4类典型生态景观类型旱季表层土壤(0—10 cm)水分的空间变化,通过主成分分析和相关分析,探讨了其生态学过程和机制。结果表明,沿严重、重度、中度和轻度的干扰递减梯度,喀斯特峰丛洼地产生了农作物(Ⅰ)→人工林(Ⅱ)→次生林(Ⅲ)→原生林(Ⅳ) 的4类典型生态景观格局变化,土壤水分显著提高,变异系数逐渐增大;4类生态景观类型的土壤水分均具有良好的空间自相关性,正负空间自相关距离反映了性质不同的两大斑块,Ⅰ、Ⅲ和Ⅳ下半部斑块的半径为50 m,拐点在坡地和洼地的分界处,Ⅱ的下半部斑块的半径为75 m,拐点是土地利用方式的转折点;不同景观类型空间变异特征不同,Ⅰ、Ⅱ、Ⅲ和Ⅳ的半变异函数分别符合指数模型、高斯模型、指数模型和球状模型,基台值(C0+C)升高,变程缩小,系统的空间总变异增强,其中Ⅰ和Ⅳ的\[C0/(C0+C)\]值分别为48.3%和39.4%,空间相关中等,Ⅱ和Ⅲ的\[C0/(C0+C)\]值≤25%,空间相关强烈;Kriging等值线图清楚表明Ⅰ和Ⅳ土壤水分呈凸型分布,Ⅱ呈单峰分布,Ⅲ呈凹型分布。主成分分析显示除海拔和坡位始终是影响4类生态景观类型土壤水分的主导因子外,不同景观类型的其他主导因子不同,且同一因子在不同景观类型与土壤水分的正负作用关系和相关程度也不同。因此,应根据4类典型生态景观类型土壤水分的空间变化及主要影响因子制定相应的水资源合理利用和管理策略。     

行为的结构、刚性和多样性

有关动物行为的定义、结构和多样性是一个被长期忽视的研究领域。然而,动物行为多样性不仅是一个生物多样性基础理论问题,也与濒危动物的成功保护有关。本文定义了动物行为以及行为的刚性与弹性,探讨了行为表达的空间条件以及生境因素与行为多样性之间的关系。我们发现雌雄大熊猫个体在较大的活动空间里的发情行为表现的频次及活动频率显著地高于那些在较小的空间里的雌雄个体,说明活动空间对雄性或雌性大熊猫的发情行为有显著影响。圈养空间影响麋鹿的社会行为、通讯行为和聚群行为。圈养在小圈中的麋鹿没有出现同性聚群现象,当圈养麋鹿野放后即表现出这种现象。圈养环境中长大的动物个体由于缺乏行为的表达空间,仅仅表现出刚性大的行为,丧失了许多弹性大的行为,从而导致动物行为的多样性下降。对那些生活在开阔草原和荒漠上的野生有蹄类动物实施迁地保护时,必须考虑其逃逸空间,为那些动物建立自然保护区时,则必须考虑其迁移空间。此外,动物行为的多样性与生境元素有关。我们应当给圈养动物提供复杂而多样的环境,以增加圈养野生动物表达寻找食物、建立领域、筑巢和避开不利环境等行为的可能性,维持濒危个体的行为多样性。     

岩溶区青冈栎的年轮特征及其与环境因子的关系

为揭示岩溶区植物生长特征及其与环境因子的关系,利用年轮分析方法研究了岩溶区广泛分布的乔木树种青冈栎的年轮特征及其与环境因子的关系.结果表明:青冈栎年轮宽度和年轮指数的平均值分别为(2.565±0.028) mm和1.108±0.012.随着胸径的增大,年轮宽度和年轮指数在逐渐增大,年轮指数与气候因子的变化有着相关关系,与前一年6月份、12月份以及当年12月份的平均温度呈显著正相关,而与前一年4月份、10月份以及当年4月份的降雨量和前一年8月份、9月份以及当年2月份的日照总时数呈显著负相关.表明岩溶区青冈栎的生长可能主要受到温度变化的影响,降雨量和日照时数的变化也影响着青冈栎的年轮特征.温度,降雨量和日照时数等环境因子共同制约着岩溶区青冈栎的生长.     

Using Input-Output Analysis to Measure the Environmental Pressure of Consumption at Different Spatial Levels

Input-output modeling is a useful tool for tracing environmental impacts of consumption. Because it includes impacts originating from production layers of infinite order (capturing the entire economy), input-output modeling is highly relevant for studies operating in a life-cycle context. In this article we show how the input-output approach can be used to enumerate the problem of sustainable consumption. Based on a literature survey including research done by the authors we present measures of the emissions of carbon dioxide at different spatial levels: nation, city, and household. Further, we take more environmental effects into account and introduce the concept of environmental efficiency by combining input-output modeling and data envelopment analysis. Finally, we discuss the policy relevance of the different measures. The article demonstrates that input-output modeling has a wide range of life-cycle oriented applications when combined with other data sources such as detailed trade statistics, foreign input-output and environmental statistics, and household expenditure data.