黄海南部和东海中北部黄鮟鱇数量分布及其与环境的关系

根据2004年4、6、9月和12月在黄海南部和东海中北部(27°00′~34°00′N、122°00′~127°00′E)进行的渔业资源大面定点底拖网调查资料,以相对资源密度指数作为指标值,分析了黄鮟鱇的时空分布特征。并利用GAM模型,分析了黄鮟鱇数量分布与经纬度、水深、底温和底盐等环境因子的关系。结果表明:黄鮟鱇主要分布在黄海南部和东海北部海区,4个季节的分布范围有明显不同,以春季为最大,冬季最小;黄鮟鱇适宜底温、底盐和水深范围分别为11~14℃、33.5~34.5和40~90 m;根据黄鮟鱇分布的底温范围,推断黄鮟鱇为冷温性鱼种。     

Prediction of sunflower grain oil concentration as a function of variety,crop management and environment using statistical models

Sunflower (Helianthus annuus L.) raises as a competitive oilseed crop in the current environmentally friendly context. To help targeting adequate management strategies, we explored statistical models as tools to understand and predict sunflower oil concentration. A trials database was built upon experiments carried out on a total of 61 varieties over the 2000–2011 period, grown in different locations in France under contrasting management conditions (nitrogen fertilization, water regime, plant density). 25 literature-based predictors of seed oil concentration were used to build 3 statistical models (multiple linear regression, generalized additive model (GAM), regression tree (RT)) and compared to the reference simple one of Pereyra-Irujo and Aguirrezábal (2007) based on 3 variables. Performance of models was assessed by means of statistical indicators, including root mean squared error of prediction (RMSEP) and model efficiency (EF). GAM-based model performed best (RMSEP = 1.95%; EF = 0.71) while the simple model led to poor results in our database (RMSEP = 3.33%; EF = 0.09). We computed hierarchical contribution of predictors in each model by means of R² and concluded to the leading determination of potential oil concentration (OC), followed by post-flowering canopy functioning indicators (LAD2 and MRUE2), plant nitrogen and water status and high temperatures effect. Diagnosis of error in the 4 statistical models and their domains of applicability are discussed. An improved statistical model (GAM-based) was proposed for sunflower oil prediction on a large panel of genotypes grown in contrasting environments.     

Subpolar gyre and temperature drive boreal fish abundance in Greenland waters

As result of ocean warming, marine boreal species have shifted their distribution poleward, with increases in abundance at higher latitudes, and declines in abundance at lower latitudes. A key to predict future changes in fish communities is to understand how fish stocks respond to climate variability. Scattered field observations in the first half of the 20th century suggested that boreal fish may coherently invade Greenland waters when temperatures rise, but this hypothesis has remained untested. Therefore, we studied how local temperature variability and the dynamics of the subpolar gyre, a large‐scale driver of oceanic conditions in the North Atlantic, affect abundance of boreal fishes in a region that sharply defines their lower thermal boundary. We analysed information from demersal trawl surveys from 1981 to 2017, for species distributed from shallow shelf to depths of 1,500 m, collected at over 10,000 stations along ~3,000 km of Greenland. Our results show that local temperature and variability of Labrador and Irminger Sea water in the subpolar gyre region drive interdecadal variability of boreal fish abundance in Greenland waters. Although temperature fluctuations were higher in shallow than deep regions, fish abundance changed as quickly in great depths as in shallow depths. This link between physics and biology provides an opportunity for prediction of future trends, which is of utility in Greenland, where fisheries constitute more than 90% of the national export value.     

Using occupancy and population models to assess habitat conservation opportunities for an isolated carnivore population

An isolated population of the fisher (Martes pennanti) in the southern Sierra Nevada, California, is threatened by small size and habitat alteration from wildfires, fuels management, and other factors. We assessed the population’s status and conservation options for its habitat using a spatially explicit population model coupled with a fisher probability of occurrence model. The fisher occurrence model was selected from a family of generalized additive models (GAM) generated using numerous environmental variables and fisher detection–nondetection data collected at 228 survey arrays sampled repeatedly during 2002–2006. The selected GAM accounted for 69% of the Akaike weight using total above-ground biomass of trees, latitude-adjusted elevation, and annual precipitation averaged over a 5 km² moving window. We estimated equilibrium population sizes (or carrying capacities) within currently occupied areas, and identified likely population source, sink, and expansion areas, by simulating population processes for 20 years using different demographic rates, dispersal distances, and territory sizes. The population model assumed that demographic parameters of fishers scale in proportion to habitat quality as indexed by the calculated probability of fisher occurrence. Based on the most defensible range of parameter values, we estimate fisher carrying capacity at ∼125–250 adults in currently occupied areas. Population expansion into potential habitat in and north of Yosemite National Park has potential to increase population size, but this potential for expansion is predicted to be highly sensitive to mortality rates, which may be elevated in the northern portion of the occupied range by human influences, including roadkill and diseases carried by domestic cats and dogs.     

The relative importance of lunar phase and environmental conditions on striped marlin (Tetrapturus audax) catches in sport fishing

We used generalized additive mixed models to analyze data on striped marlin (Tetrapturus audax) catches in Baja California sport fisheries (1987–1989) to investigate the relative importance of lunar phase, sea surface temperature (SST), El Niño/Southern Oscillation (ENSO) index, and vessel effects on catch per unit effort (CPUE). The results indicate that the moon phase has no or little (<1% of variance explained) influence on CPUE. In contrast, both SST (10%) and ENSO (6%) influenced CPUE positively. While most of the variation in CPUE remains unexplained (53%), the vessel identity explained small (ca. 1.5%) but significant amount of variance in CPUE. Hence, sport fishermen wishing to maximise their striped marlin catches would best plan their trips on the basis of weather conditions and boat/crew identities, rather than on the basis of lunar phase.     

黄海中部夏季鳀鱼卵、仔稚鱼分布与早期生长特征

摘 要：鳀（Engraulis japonicus）是黄海重要的捕捞对象，也是蓝点马鲛等大型鱼类的主要饵料。探究鳀早期生活史阶段的生长特征，是深入了解鳀补充机制的重要基础。本研究基于2019年夏季黄海中部断面调查数据，利用Tweedie GAM模型研究了鳀鱼卵和仔稚鱼分布与环境因子的关系，并基于鳀仔稚鱼耳石微结构分析，估算了鳀仔稚鱼的日龄和体长组成，逆推孵化日期，构建幂函数早期生长方程。结果显示，2019年夏季在山东半岛南部35°N断面形成鳀鱼卵的密集分布区，仔稚鱼密集分布区在123.5°E、35.5-36.5°N纵向断面海域。盐度对鱼卵、仔稚鱼的分布都有显著影响，最适盐度范围均在30-32，温度仅对鱼卵的分布有显著影响，最适温度范围在23-26℃。本研究共鉴定和分析211尾鳀仔稚鱼的日龄，体长范围集中在10-22 mm，优势体长组是12-14mm，日龄范围集中在16-30d，优势日龄组是19-21d；耳石增长率范围为3.08-5.90μm/d，分析比较了两个航次鳀仔稚鱼耳石增长率的变化特征，发现耳石增长率的变化趋势具有显著的差异，可能与月份间的温度差异有关。本研究为鳀资源的早期生长和补充机制提供了科学依据。     

The effect of exposure on landscape scale soil surface temperatures and species distribution models

Species distribution models (SDMs) often use elevation as a surrogate for temperature or utilise elevation sensitive interpolations from weather stations. These methods may be unsuitable at the landscape scale, especially where there are sparse weather stations, dramatic variations in exposure or low elevational ranges. The goal of this study was to determine whether radiation, moisture or a novel estimate of exposure could improve temperature estimates and SDMs for vegetation on the Illawarra Escarpment, near Sydney, Australia. Forty temperature sensors were placed on the soil surface of an approximately 12,000 ha study site between November 2004 and August 2006. Linear regression was used to determine the relationship with environmental factors. Elevation was correlated more with moderate temperatures (winter maximums, summer minimums, spring and autumn averages) than extreme temperatures (summer maximums, winter minimums). The correlation (r ²) between temperature and environmental factors was improved by up to 0.38 by incorporating exposure, moisture and radiation in the regressions. Summer maximums and winter minimums were predominately determined by exposure to the NW and coastal influences respectively, while exposure to the NE and SW was important during other seasons. These directions correspond with the winds that are most influential in the study area. The improved temperature estimates were used in Generalised Additive Models for 37 plant species. The deviance explained by most models was increased relative to elevation, especially for moist rainforest species. It was concluded that improving the accuracy of seasonal temperature estimates could improve our ability to explain the patchy distribution of many species. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

异常气候下温跃层及时空因子对中西太平洋黄鳍金枪鱼渔场分布的影响

为研究气候变化对渔业资源的影响,采用2008—2017年全球海洋Argo网格数据集（BOA_Argo）和同期商业渔船渔捞日志数据,分析了拉尼娜和厄尔尼诺年中西太平洋黄鳍金枪鱼围网主要作业渔场温跃层的时空变化特征,结合GAM（generalized additive model）对影响黄鳍金枪鱼渔场的变量进行分析。结果表明,拉尼娜年,单位捕捞努力量渔获量(catch per unit effort, CPUE)随温跃层上界温度的高值区向西收缩而西移,最西至145°E;厄尔尼诺年,东移至165°E以东。拉尼娜年较正常年份,赤道太平洋东、西侧温跃层的上界深度差拉大,80~130 m上界深度值偏西。温跃层强度整体上呈现西弱东强,温跃层厚度以15°N和15°S为轴线,分别存在一个较厚的带状分布结构,CPUE分布在厚度值120~200 m之间。温跃层上界温度为27.5～29.5 ℃、强度为0.08～0.13 ℃·m^-1时,CPUE分布密集,温跃层参数中上界温度对CPUE分布的影响最大。且厄尔尼诺年CPUE的东移和拉尼娜年CPUE的西移随渔场所在温跃层的最适参数值而移动。时间因子中年份对CPUE的影响是波动性的,拉尼娜年对CPUE的影响更密切。资源丰度较高海域在5°N—5°S,150°E—175°E。综上所述,异常气候导致的温跃层变化对于CPUE具有显著影响。     

Potential landscape drivers of biodiversity components in a flood plain: Past or present patterns?

Changes in landscape pattern under the control of agriculture intensification are considered to be an important driver of biodiversity and often a threat for conservation. The response of species to landscape changes is complex, including possible time lags, and depends on the taxonomic group. The search for surrogate species or surrogate data for biodiversity is confronted with this complexity.This study was conducted on two taxonomic groups (birds and vascular plants) for 20 sites each of 1 km² equally distributed in the Seine valley floodplain. For plants, two habitats were studied: grasslands and hedges. We used a generalised additive model (GAM) and co-inertia analyses to determine whether present or past landscape attributes can best explain the biodiversity components (structure and composition). This study confirms the major role of landscape pattern attributes for predicting some metrics of biodiversity, e.g. species richness. But this study shows that potential drivers of biodiversity come from both the past and present landscape patterns. The quality of surrogates for biodiversity is strongly dependent on understanding the importance of past conditions. This suggests the need for more functional surrogates, taking into account the situation of equilibrium or non-equilibrium between biodiversity and its drivers.     

导入澳血公羊对甘肃高山细毛羊生产性能的影响研究

试验探讨了通过导入体大高产澳血公羊对甘肃高山细毛羊F1、F2代周岁母羊主要生产性能的影响。从体侧毛长、体重、剪毛量、纤维直径、净毛率等主要生产性能进行了分析比较,为培育甘肃高山细毛羊体大高产品系奠定基础。结果表明:(1)F1代周岁母羊与同龄甘肃高山细毛羊超细品系母羊相比,羊毛长度增长了0.398cm(P0.01),体重增加了3.7949kg(P0.01),剪毛量有所增加(P0.01),毛纤维变粗(P0.01),净毛率没有变化。(2)F2代周岁母羊羊毛细度变化不显明,与甘肃高山细毛羊超细品系母羊相比变粗了1.294μm(P0.01);毛长和剪毛量有所提高(P0.01);体重分别较甘肃高山细毛羊和甘肃高山细毛羊超细品系母羊增加了3.3051kg(P0.01)、1.0648kg(P0.05);净毛率没有变化(P0.05)。