Distinguish water utilization strategies of trees growing on earth‐rocky mountainous area with transpiration and water isotopes

Water stress is regarded as a global challenge to forests. Unlike other water‐limited areas, the water use strategies of rocky mountainous forests, which play an important ecohydrological role, have not received sufficient attention. To prove our hypothesis that species adopt different water use strategies to avoid competition of limited water resources, we used site abiotic monitoring, sap flow and stable isotope method to study the biophysiological responses and water use preferences of two commonly distributed forest species, Pinus tabuliformis (Pt) and Quercus variabilis (Qv). The results showed that Pt transpired higher than Qv. Pt was also prone to adopt isohydric water use strategy as it demonstrated sensitive stomatal control over water loss through transpiration. Qv developed cavitation which was reflected by the dropping E_c in response to high vapor pressure deficit, concentrated peak sap flux density (J_s), and enlarged hysteresis loop. Considering the average soil depth of 52.8 cm on the site, a common strategy shared by both species was the ability to tap water from deep soil layers (below 40 cm) when soil water was limited, and this contributed to the whole growing season transpiration. The contribution of surface layer water to plant water use increased and became the main water source for transpiration after rainfall. Qv was more efficient at using water from surface layer than Pt due to the developed surface root system when soil water content was not stressed. Our study proves that different water‐using strategies of co‐occurring species may be conducive to avoid competition of limited water resources to guarantee their survival. Knowledge of water stress‐coping strategies of trees has implications for the understanding and prediction of vegetation composition in similar areas and can facilitate forest management criteria for plantations.     

Contrasting behavior between two populations of an ice‐obligate predator in East Antarctica

The Austral autumn–winter is a critical period for capital breeders such as Weddell seals that must optimize resource acquisition and storage to provision breeding in the subsequent spring. However, how Weddell seals find food in the winter months remains poorly documented. We equipped adult Weddell seals after their annual molt with satellite‐relayed data loggers at two sites in East Antarctica: Dumont D'Urville (n = 12, DDU) and Davis (n = 20). We used binomial generalized mixed‐effect models to investigate Weddell seals’ behavioral response (i.e., “hunting” vs. “transit”) to physical aspects of their environment (e.g., ice concentration). Weddell seal foraging was concentrated to within 5 km of a breathing hole, and they appear to move between holes as local food is depleted. There were regional differences in behavior so that seals at Davis traveled greater distances (three times more) and spent less time in hunting mode (half the time) than seals at DDU. Despite these differences, hunting dives at both locations were pelagic, concentrated in areas of high ice concentration, and over areas of complex bathymetry. There was also a seasonal change in diving behavior from transiting early in the season to more hunting during winter. Our observations suggest that Weddell seal foraging behavior is plastic and that they respond behaviorally to changes in their environment to maximize food acquisition and storage. Such plasticity is a hallmark of animals that live in very dynamic environments such as the high Antarctic where resources are unpredictable.     

Investigating the genomic basis of discrete phenotypes using a Pool‐Seq‐only approach: New insights into the genetics underlying colour variation in diverse taxa

While large‐scale genomic approaches are increasingly revealing the genetic basis of polymorphic phenotypes such as colour morphs, such approaches are almost exclusively conducted in species with high‐quality genomes and annotations. Here, we use Pool‐Seq data for both genome assembly and SNP frequency estimation, followed by scanning for F_ST outliers to identify divergent genomic regions. Using paired‐end, short‐read sequencing data from two groups of individuals expressing divergent phenotypes, we generate a de novo rough‐draft genome, identify SNPs and calculate genomewide F_ST differences between phenotypic groups. As genomes generated by Pool‐Seq data are highly fragmented, we also present an approach for super‐scaffolding contigs using existing protein‐coding data sets. Using this approach, we reanalysed genomic data from two recent studies of birds and butterflies investigating colour pattern variation and replicated their core findings, demonstrating the accuracy and power of a Pool‐Seq‐only approach. Additionally, we discovered new regions of high divergence and new annotations that together suggest novel parallels between birds and butterflies in the origins of their colour pattern variation.     

Nearly a decade‐long repeatable seasonal diversity patterns of bacterioplankton communities in the eutrophic Lake Donghu (Wuhan,China)

Uncovering which environmental factors govern community diversity patterns and how ecological processes drive community turnover are key questions related to understand the community assembly. However, the ecological mechanisms regulating long‐term variations of bacterioplankton communities in lake ecosystems remain poorly understood. Here we present nearly a decade‐long study of bacterioplankton communities from the eutrophic Lake Donghu (Wuhan, China) using 16S rRNA gene amplicon sequencing with MiSeq platform. We found strong repeatable seasonal diversity patterns in terms of both common (detected in more than 50% samples) and dominant (relative abundance >1%) bacterial taxa turnover. Moreover, community composition tracked the seasonal temperature gradient, indicating that temperature is a key environmental factor controlling observed diversity patterns. Total phosphorus also contributed significantly to the seasonal shifts in bacterioplankton composition. However, any spatial pattern of bacterioplankton communities across the main lake areas within season was overwhelmed by their temporal variabilities. Phylogenetic analysis further indicated that 75%–82% of community turnover was governed by homogeneous selection due to consistent environmental conditions within seasons, suggesting that the microbial communities in Lake Donghu are mainly controlled by niche‐based processes. Therefore, dominant niches available within seasons might be occupied by similar combinations of bacterial taxa with modest dispersal rates throughout different lake areas.     

Gene expression and molecular characterization of a novel C-type lectin,encapsulation promoting lectin (EPL), in the rice armyworm,Mythimna separata

Insect cellular immune reactions differ depending on the target species. Phagocytosis is activated to scavenge microorganisms such as bacteria and fungi. On the other hand, larger invaders such as parasitoid wasps are eliminated by activation of encapsulation. In this study, we hypothesized that novel determinants regulate cellular immunities independent of surface molecular pattern recognition involving pattern recognition receptors (PRRs). Immune-related genes differentially expressed depending on the treated material size were screened in larval hemocytes of the rice armyworm, Mythimna separata. Consequently, we identified a novel C-type lectin gene up-regulated by injection of large beads but not small beads of identical material. Examination of in vitro effect of the recombinant protein on the immune reactions clarified that the protein activated encapsulation reaction, while it suppressed phagocytosis. These results suggest that this novel C-type lectin designated “encapsulation promoting lectin (EPL)” regulates cellular immunity by a novel immune target size-recognition mechanism.     

卧龙自然保护区大熊猫空间利用格局动态变化特征

野生动物在长期的栖息地选择过程中,能判断其生境质量,而趋向于选择既能降低能量消耗,又能获得营养价值和能量净收益较高的有利生境。以往的研究多是从统计学方法或宏观尺度对大熊猫生境进行评价,很少考虑到野生动物自身生物学特性及生境选择过程中的空间利用特征。本研究结合家域模型与景观格局分析技术定量分析大熊猫实际空间利用格局的动态变化特征及其破碎化程度,进而反映不同时期大熊猫生境选择模式及栖息地生境适宜性的动态变化。结果表明：卧龙自然保护区大熊猫在对栖息地的实际利用过程中向更适宜的区域集中,使得高适宜等级区域面积有所增大;而边缘生境区域更容易受到自然灾害和人为因素的干扰,破碎化加剧,需要在保护工作中引起足够的重视。从大熊猫行为模式特征出发,在不同时空尺度上,评估大熊猫对生境选择的空间格局变化特征,丰富了野生动物栖息地适宜性评价的时空尺度选择,为更准确地制定保护区管理政策提供了有效的工具。     

Disentangling confusions in inflorescence morphology:Patterns and diversity of reproductive shoot ramification in angiosperms

Terminology of inflorescence diversity has often been used in a confusing way in the literature,partly because it was based on uncritical and outdated definitions.In particular,the terms cyme,thyrse,and panicle have been misused.Although a more critical classification worked out by several authors is available,it is unfortunately not in general use because most of the relevant publications are written in German.In addition,some terms have not been used in the same way by morphologists and developmental geneticists.The present review attempts to remedy the situation with a simple outline of a classification based on:(i)different branching patterns;(ii)differential elongation of axes of different orders;and(iii)repetition of basic ramification patterns in different ways.Racemose and cymose branching are two extreme patterns;the former with limitation of axial orders to two,the second with limitation of lateral axes of each order to two.In a branching system,a sequence of racemose→cymose and,within the cyme,of dichasial→monochasial is common,but the reverse sequence generally does not occur.Systematic and evolutionary aspects of inflorescences are briefly discussed.Branching patterns are often stable in larger clades.Inflorescences of mutants studied in developmental genetic studies are mainly altered in flower or branch numbers or relative branch length,but not in branching patterns.This is also a contribution towards the goal of a unified terminology for the different fields of biology dealing with inflorescences.     

Native and alien plant species richness in relation to spatial heterogeneity on a regional scale in Germany

Aim The aim of our study was to reveal relationships between richness patterns of native vs. alien plant species and spatial heterogeneity across varying landscape patterns at a regional scale. Location The study was carried out in the administrative district of Dessau (Germany), covering around 4000 km². Methods Data on plant distribution of the German vascular flora available in grid cells covering 5′ longitude and 3′ latitude (c. 32 km²) were divided into three status groups: native plants, archaeophytes (pre 1500 AD aliens) and neophytes (post 1500 AD aliens). Land use and abiotic data layers were intersected with 125 grid cells comprising the selected area. Using novel landscape ecological methods, we calculated 38 indices of landscape composition and configuration for each grid cell. Principal components analysis (PCA) with a set of 29 selected, low correlated landscape indices was followed by multiple linear regression analysis. Results PCA reduced 29 indices to eight principal components (PCs) that explained 80% cumulative variance. Multiple linear regression analysis was highly significant and explained 41% to 60% variance in plant species distribution (adjusted R²) with three significant PCs (tested for spatial autocorrelation) expressing moderate to high disturbance levels and high spatial heterogeneity. Comparing the significance of the PCs for the species groups, native plant species richness is most strongly associated with riverine ecosystems, followed by urban ecosystems, and then small‐scale rural ecosystems. Archaeophyte and neophyte richness are most strongly associated with urban ecosystems, followed by small‐scale rural ecosystems and riverine ecosystems for archaeophytes, and riverine ecosystems and small‐scale rural ecosystems for neophytes. Main conclusions Our overall results suggest that species richness of native and alien plants increases with moderate levels of natural and/or anthropogenic disturbances, coupled with high levels of habitat and structural heterogeneity in urban, riverine, and small‐scale rural ecosystems. Despite differences in the order of relevance of PCs for the three plant groups, we conclude that at the regional scale species richness patterns of native plants as well as alien plants are promoted by similar factors.     

Biodiversity conservation and cash crop development in northern Thailand

This study examines some of the implications of increased cash croppingfor wildlife in the highlands of northern Thailand. Through in-depth study of twoHmong villages and interviews in several others, information was collectedregarding cash crop adoption patterns, comparisons between various cash crops interms of inputs and yields and trends in land use change and hunting behaviour.The results show that the newer cash crops, cabbage and carnations inparticular, have greater abilities to support larger human populations per unitland area and thereby reduce pressure for increased land clearing. However,strong concerns remain regarding the chemical inputs used on thesecrops. Since the adoption of cash cropping, hunting frequency has declined. Interviewees provided seven reasons, withthe time requirements for cash crop tending being the main one. Hunting isstill practiced but largely for social rather than economic reasons. Oneexception is the regular hunting of small animals by opium addicts. Others nowhave sufficient money to be able to buy meat. Hunters span all economic classes.Hunting now plays a reduced social role in the society. In general, the youngergeneration has reduced knowledge of the forest environment. No support was foundfor the hypothesis that cash cropping had reduced village regulations onhunting, as few such regulations exist amongst the Hmong. This study suggeststhat there may be advantages to biodiversity conservation from cash cropping inthe highlands of SE Asia and confirms the much broader scope that conservationscientists must embrace in order to understand all the factors that mightinfluence biodiversity in a region.     

圈养马麝夏秋冬活动格局的比较

2000年6月至2001年1月间,在甘肃兴隆山保护区麝场对46只圈养马麝进行扫描取样观察,记录其站立及运动、摄食、反刍和静卧4种行为,并对各行为的发生率进行了统计分析。结果表明：圈养马麝的活动有昼夜节律和季节变化,夏季活动型属于晨昏型偏夜型,秋季偏向昼夜型,冬季也属昼夜型但趋于白昼活动;除季节间分布不一的晨昏活动高峰期外,3个季节均有相对恒定的午夜（22：00－01：30）活动高峰;气温是影响圈养马麝活动格局的主要因子。