利用红外相机公里网格调查钱江源国家公园的兽类及鸟类多样性

2014年5月至2019年4月, 作者采用红外相机技术调查了浙江省钱江源国家公园的兽类及鸟类多样性。将整个国家公园划分为267个1 km × 1 km的调查网格, 每个网格内设置3个固定调查位点, 使用1台红外相机定期在同一网格内的位点之间进行轮换。其中, 古田山片区在5年内共完成14轮次调查, 古田山以外的区域自2018年7月纳入调查范围, 何田、长虹片区完成2次轮换, 齐溪片区完成1次轮换。在253个网格内的741个有效位点上共获得140,413个相机工作日的数据, 采集兽类和鸟类的照片和视频268,833份, 有效探测数74,368次, 鉴定出21种野生兽类, 72种野生鸟类, 5种家畜及家禽。包括国家一级重点保护野生动物2种, 即黑麂(Muntiacus crinifrons)、白颈长尾雉(Syrmaticus ellioti); 国家二级重点保护野生动物17种, 合计占野生物种总数的20.4%。被IUCN物种红色名录评估为易危(VU)的5种, 近危(NT)的4种, 合计占物种总数的9.7%。被中国脊椎动物红色名录评估为濒危(EN)的1种, 易危(VU)的9种, 近危(NT)的10种, 合计占物种总数的21.5%。相对多度指数最高的大中型兽类为小麂(Muntiacus reevesi), 鸟类为白鹇(Lophura nycthemera)。本次调查获得了国家公园内兽类和鸟类的多样性组成、空间分布和相对多度, 为长期科研监测和科学管理提供了基础数据。     

贵州梵净山国家级自然保护区鸟兽红外相机监测

红外相机监测是了解野生动物多样性现状、动态变化和面临威胁的重要手段。本研究采用网格抽样调查法, 在贵州梵净山国家级自然保护区内选取2个监测样区共40个监测位点布设红外相机, 对区内兽类和鸟类物种进行监测调查。2017年4月至2018年12月间, 红外相机累积监测14,808个相机工作日, 共收集有效照片14,119张, 独立有效物种照片3,199张。共鉴定野生动物9目22科61种, 其中兽类26种, 隶属于4目12科; 鸟类35种, 隶属于5目10科。记录到国家I级重点保护野生动物2种: 黔金丝猴(Rhinopithecus brelichi)和白颈长尾雉(Syrmaticus ellioti), 国家II级重点保护野生动物9种; 被IUCN红色名录评估为濒危(EN)的1种、易危(VU)的5种、近危(NT)的8种。物种的相对多度指数(relative abundance index, RAI)分析结果显示, 藏酋猴(Macaca thibetana, RAI = 28.23)、毛冠鹿(Elaphodus cephalophus, RAI = 15.46)、野猪(Sus scrofa, RAI = 11.82)、小麂(Muntiacus reevesi, RAI = 9.05)、黔金丝猴(RAI = 7.70)为相对多度最高的5种兽类; 紫啸鸫(Myophonus insularis, RAI = 10.33)、红腹角雉(Tragopan temminckii, RAI = 9.59)、红腹锦鸡(Chrysolophus pictus, RAI = 6.96)、白颈长尾雉(RAI = 3.71)、勺鸡(Pucrasia macrolopha, RAI = 1.55)为相对多度最高的5种鸟类。另外, 红外相机还监测到较多的家畜活动(RAI = 11.14)和人为活动(RAI = 12.90), 保护区管理部门仍需采取相应管理措施, 进一步提高周边居民的保护意识, 促进保护区与社区的协调发展。     

Data partitioning and correction for ascertainment bias reduce the uncertainty of placental mammal divergence times inferred from the morphological clock

Bayesian estimates of divergence times based on the molecular clock yield uncertainty of parameter estimates measured by the width of posterior distributions of node ages. For the relaxed molecular clock, previous works have reported that some of the uncertainty inherent to the variation of rates among lineages may be reduced by partitioning data. Here we test this effect for the purely morphological clock, using placental mammals as a case study. We applied the uncorrelated lognormal relaxed clock to morphological data of 40 extant mammalian taxa and 4,533 characters, taken from the largest published matrix of discrete phenotypic characters. The morphologically derived timescale was compared to divergence times inferred from molecular and combined data. We show that partitioning data into anatomical units significantly reduced the uncertainty of divergence time estimates for morphological data. For the first time, we demonstrate that ascertainment bias has an impact on the precision of morphological clock estimates. While analyses including molecular data suggested most divergences between placental orders occurred near the K‐Pg boundary, the partitioned morphological clock recovered older interordinal splits and some younger intraordinal ones, including significantly later dates for the radiation of bats and rodents, which accord to the short‐fuse hypothesis.     

Differential roles of species richness versus species asynchrony in regulating community stability along a precipitation gradient

Plant community may provide products and services to humans. However, patterns and drivers of community stability along a precipitation gradient remain unclear. A regional‐scale transect survey was conducted over a 3‐year period from 2013 to 2015, along a precipitation gradient from 275 to 555 mm and spanning 440 km in length from west to east in a temperate semiarid grassland of northern China, a central part of the Eurasian steppe. Our study provided regional‐scale evidence that the community stability increased with increasing precipitation in the semiarid ecosystem. The patterns of community stability along a precipitation gradient were ascribed to community composition and community dynamics, such as species richness and species asynchrony, rather than the abiotic effect of precipitation. Species richness regulated the temporal mean (μ) of aboveground net primary productivity (ANPP), while species asynchrony regulated the temporal standard deviation (σ) of ANPP, which in turn contributed to community stability. Our findings highlight the crucial role of community composition and community dynamics in regulating community stability under climate change.     

Does perspective matter? A case study comparing Eulerian and Lagrangian estimates of common murre (Uria aalge) distributions

Studies estimating species' distributions require information about animal locations in space and time. Location data can be collected using surveys within a predetermined frame of reference (i.e., Eulerian sampling) or from animal‐borne tracking devices (i.e., Lagrangian sampling). Integration of observations obtained from Eulerian and Lagrangian perspectives can provide insights into animal movement and habitat use. However, contemporaneous data from both perspectives are rarely available, making examination of biases associated with each sampling approach difficult. We compared distributions of a mobile seabird observed concurrently from ship, aerial, and satellite tag surveys during May, June, and July 2012 in the northern California Current. We calculated utilization distributions to quantify and compare variability in common murre (Uria aalge) space use and examine how sampling perspective and platform influence observed patterns. Spatial distributions of murres were similar in May, regardless of sampling perspective. Greatest densities occurred in coastal waters off southern Washington and northern Oregon, near large murre colonies and the mouth of the Columbia River. Density distributions of murres estimated from ship and aerial surveys in June and July were similar to those observed in May, whereas distributions of satellite‐tagged murres in June and July indicated northward movement into British Columbia, Canada, resulting in different patterns observed from Eulerian and Lagrangian perspectives. These results suggest that the population of murres observed in the northern California Current during spring and summer includes relatively stationary individuals attending breeding colonies and nonstationary, vagile adults and subadults. Given the expected growth of telemetry studies and advances in survey technology (e.g., unmanned aerial systems), these results highlight the importance of considering methodological approaches, spatial extent, and synopticity of distribution data sets prior to integrating data from different sampling perspectives.     

普通野生稻线粒体蛋白质编码基因密码子使用偏好性的分析

以普通野生稻(Oryza rufipogon Griff.)线粒体基因组为对象,分析其蛋白质编码基因的密码子使用特征及与亚洲栽培稻(O. sativa L.)的差异,探讨其密码子偏性形成的影响因素和进化过程。结果显示:普通野生稻线粒体基因组编码序列第1、第2和第3位碱基的GC含量依次为49.18%、42.67%和40.86%;有效密码子数(Nc)分布于45.32～61.00之间,其密码子偏性较弱; Nc值仅与GC_3呈显著相关,密码子第3位的碱基组成对密码子偏性影响较大;第1向量轴上显示9.91%的差异,其与GC_3s、Nc、密码子偏好指数(CBI)和最优密码子使用频率(Fop)的相关性均达到显著水平;而GC_3和GC₁₂的相关性未达到显著水平。因此,普通野生稻线粒体基因组密码子的使用偏性主要受自然选择压力影响而形成。本研究确定了21个普通野生稻线粒体基因组的最优密码子,大多以A或T结尾,与叶绿体密码子具有趋同进化,但是与核基因组具有不同的偏好性。同义密码子相对使用度(RSCU)、PR2偏倚分析和中性绘图分析显示,普通野生稻线粒体基因功能和其密码子使用密切相关,且线粒体密码子使用在普通野生稻、粳稻(O. sativa L. subsp. japonica Kato)和籼稻(O. sativa L. subsp.indica Kato)内具有同质性。     

Integration of ground survey and remote sensing derived data: Producing robust indicators of habitat extent and condition

The availability of suitable habitat is a key predictor of the changing status of biodiversity. Quantifying habitat availability over large spatial scales is, however, challenging. Although remote sensing techniques have high spatial coverage, there is uncertainty associated with these estimates due to errors in classification. Alternatively, the extent of habitats can be estimated from ground‐based field survey. Financial and logistical constraints mean that on‐the‐ground surveys have much lower coverage, but they can produce much higher quality estimates of habitat extent in the areas that are surveyed. Here, we demonstrate a new combined model which uses both types of data to produce unified national estimates of the extent of four key habitats across Great Britain based on Countryside Survey and Land Cover Map. This approach considers that the true proportion of habitat per km² (Z_i) is unobserved, but both ground survey and remote sensing can be used to estimate Z_i. The model allows the relationship between remote sensing data and Z_i to be spatially biased while ground survey is assumed to be unbiased. Taking a statistical model‐based approach to integrating field survey and remote sensing data allows for information on bias and precision to be captured and propagated such that estimates produced and parameters estimated are robust and interpretable. A simulation study shows that the combined model should perform best when error in the ground survey data is low. We use repeat surveys to parameterize the variance of ground survey data and demonstrate that error in this data source is small. The model produced revised national estimates of broadleaved woodland, arable land, bog, and fen, marsh and swamp extent across Britain in 2007.     

Evidence for targeting common siRNA hotspots and GC preference by plant Dicer-like proteins

Small interfering (si)RNAs isolated from Brassica juncea leaves infected by Turnip mosaic virus (TuMV) were characterized by cloning and sequencing. The TuMV siRNA population was dominated by 21 and 22-nt long species originated mainly from the same siRNA hotspots, indicating operational similarity between the plant Dicer-like (DCL) enzymes. Robust GC bias was observed for TuMV siRNAs versus the virus genome, indicating that DCL was more likely to target GC-rich regions. Furthermore, dicot micro-(mi)RNAs displayed higher GC% than their DCL1 substrate RNAs, implicating that the GC bias may be ancient, therefore may be important for the RNAi technology.     

Probable blind spot in the International Diabetes Federation definition of metabolic syndrome

Objectives: The International Diabetes Federation (IDF) proposed a novel definition of the metabolic syndrome (MS) in 2005, which designated central obesity as mandatory. The new National Cholesterol Education Program (NCEP) version, announced by the American Heart Association and National Heart Lung and Blood Institute in October 2005, did not favor any of the five components. We set out to compare the cardiovascular profiles of patients cross‐defined by these two definitions to shed light on the differential meanings of the two. Research Methods and Procedures: We analyzed data from 2608 non‐institutionalized adults (≥19 years old) in the National Nutrition and Health Survey in Taiwan, who had complete data for the five MS defining components. Both definitions adopted lower cut‐points for fasting glucose and race‐specific cut‐points for waist circumference. Results: Under the IDF's and new NCEP's definitions, the MS prevalence was 6.2% and 11.6% in men and 12.6% and 16.5% in women, respectively. Although the two definitions had high agreement, IDF failed to pick up ～4% to 5% of people with more than three MS component disorders but a waist circumference less than the cut‐point. Subjects whose physical conditions only satisfied NCEP's definition had similar or worse metabolic profiles than those whose conditions satisfied both IDF's definition and the new NCEP's definition. Discussion: The IDF definition would fail to identify a portion of people who have more than three MS component disorders but a small waistline. Further research and discussion are needed on whether and how to implement the IDF's definition.