A Double-Observer Method to Estimate Detection Rate During Aerial Waterfowl Surveys

Abstract We evaluated double-observer methods for aerial surveys as a means to adjust counts of waterfowl for incomplete detection. We conducted our study in eastern Canada and the northeast United States utilizing 3 aerial-survey crews flying 3 different types of fixed-wing aircraft. We reconciled counts of front- and rear-seat observers immediately following an observation by the rear-seat observer (i.e., on-the-fly reconciliation). We evaluated 6 a priori models containing a combination of several factors thought to influence detection probability including observer, seat position, aircraft type, and group size. We analyzed data for American black ducks (Anas rubripes) and mallards (A. platyrhynchos), which are among the most abundant duck species in this region. The best-supported model for both black ducks and mallards included observer effects. Sample sizes of black ducks were sufficient to estimate observer-specific detection rates for each crew. Estimated detection rates for black ducks were 0.62 (SE = 0.10), 0.63 (SE = 0.06), and 0.74 (SE = 0.07) for pilot-observers, 0.61 (SE = 0.08), 0.62 (SE = 0.06), and 0.81 (SE = 0.07) for other front-seat observers, and 0.43 (SE = 0.05), 0.58 (SE = 0.06), and 0.73 (SE = 0.04) for rear-seat observers. For mallards, sample sizes were adequate to generate stable maximum-likelihood estimates of observer-specific detection rates for only one aerial crew. Estimated observer-specific detection rates for that crew were 0.84 (SE = 0.04) for the pilot-observer, 0.74 (SE = 0.05) for the other front-seat observer, and 0.47 (SE = 0.03) for the rear-seat observer. Estimated observer detection rates were confounded by the position of the seat occupied by an observer, because observers did not switch seats, and by land-cover because vegetation and landform varied among crew areas. Double-observer methods with on-the-fly reconciliation, although not without challenges, offer one viable option to account for detection bias in aerial waterfowl surveys where birds are distributed at low density in remote areas that are inaccessible by ground crews. Double-observer methods, however, estimate only detection rate of animals that are potentially observable given the survey method applied. Auxiliary data and methods must be considered to estimate overall detection rate.     

Can digital image classification be used as a standardised method for surveying peatland vegetation cover?

The ability to carry out systematic, accurate and repeatable vegetation surveys is an essential part of long-term scientific studies into ecosystem biodiversity and functioning. However, current widely used traditional survey techniques such as destructive harvests, pin frame quadrats and visual cover estimates can be very time consuming and are prone to subjective variations. We investigated the use of digital image techniques as an alternative way of recording vegetation cover to plant functional type level on a peatland ecosystem. Using an established plant manipulation experimental site at Moor House NNR (an Environmental Change Network site), we compared visual cover estimates of peatland vegetation with cover estimates using digital image classification methods, from 0.5 m × 0.5 m field plots. Our results show that digital image classification of photographs taken with a standard digital camera can be used successfully to estimate dwarf-shrub and graminoid vegetation cover at a comparable level to field visual cover estimates, although the methods were less effective for lower plants such as mosses and lichens. Our study illustrates the novel application of digital image techniques to provide a new way of measuring and monitoring peatland vegetation to the plant functional group level, which is less vulnerable to surveyor bias than are visual field surveys. Furthermore, as such digital techniques are highly repeatable, we suggest that they have potential for use in long-term monitoring studies, at both plot and landscape scales.     

Concrete density estimation of linac bunker walls using impact-echo testing

PurposeTo estimate the concrete density of a newly constructed bunker using impact-echo testing prior to the installation of the linear accelerator.MethodsA newly constructed bunker showed visible honeycombing after the removal of the construction formwork. Impact-echo testing, which is based on the propagation and reflection of elastic waves in solids, was applied to confirm the bunker shielding integrity. A mechanical impact on the bunker wall generates a stress pulse, which propagates through the wall and is reflected or refracted by voids or changes in material characteristics such as density. Surface displacements caused by the reflected waves are recorded by a transducer, located near the impact point. The resulting displacement-time curves are analysed in the frequency domain for anomalies. The dominant frequencies are related to the depths from which stress waves are reflected within the structure. If the dynamic elastic modulus and Poisson ratio of the concrete are known, then the measured velocity of the so-called P-wave can be related to the concrete density.ResultsValidation measurements on a wall with known concrete density gave an estimate within 3% of the true density. Measured velocities on the honeycombed wall ranged from 3750 m/s to 4300 m/s, corresponding to densities of 2894 kg/m³ and 2201 kg/m³ respectively, with the majority of estimated densities ranging from 2307 kg/m³ to 2544 kg/m³.A radiation survey after the installation of the linear accelerator confirmed adequate shielding.ConclusionImpact-echo testing presents a viable solution to confirm bunker shielding integrity before the installation of a linac.     

A survey of family‐group names in noctuoid moths (Insecta: Lepidoptera)

Some milestones of the systematic history of the Noctuoidea are reviewed, and a full list of the family‐group names is given including the respective bibliographical references. Every name has been checked for availability according to the Iczn. The following subjective synonyms are indicated: Eublemmini Forbes, 1954 (=*Anthophilidae Duponchel, [1845], unavailable, = *Micradi Stephens, 1850, unavailable, no need for replacement names). According to Art. 40. 2 Iczn, we propose to maintain the names Thaumetopoeinae Aurivillius, 1889 (= Cnethocampides Wallengren, 1861), Psaphidini Grote, 1896 (= Dicopinae Grote, 1882), and Euxoinae Warren, 1909 (= Brotinae Grote, 1882, = Euxoina Beck, 1999 syn. n.), as they are in current use.     

Hirschmanniella spp. in Rice Fields of Vietnam

Root and soil samples from one-crop and two-crop rice fields were collected in a survey for Hirschmanniella spp. in Vietnam during 1978-80. Hirschmanniella spp. were found in 50-78% of the soil samples and 98-100% of the root samples collected. Population densities of nematodes in root systems were lowest at posttransplanting and highest at heading time. Numbers of nematodes inside roots increased 20-22 times from transplanting to heading in fields with both crop sequences. Population densities of Hirschmanniella spp. in two-crop rice fields were more than twice those in one-crop rice fields.     

崖壁植物太行菊与长裂太行菊全基因组大小及特征分析北大核心CSCD

太行菊(Opisthopappus taihangensis)、长裂太行菊(O.longilobus),为太行山特有多年生崖壁草本植物,菊科(Compositae)重要野生资源,具有较高的经济与生态价值。为确定适合两物种的全基因组测序策略,该研究利用流式细胞法和高通量测序技术,分析两物种基因组大小、杂合率、重复序列及GC含量等信息。结果表明:(1)流式细胞法估算太行菊基因组大小约为2.1 Gb,长裂太行菊基因组大小约为2.4 Gb。(2)高通量测序修正后太行菊基因组大小为3.13 Gb,重复序列比例为84.35%,杂合度为0.99%,GC含量为36.56%;长裂太行菊基因组为3.18 Gb,重复序列比例为83.83%,杂合度为1.17%,GC含量为36.62%。(3)初步组装后GC含量分布及平均深度存在异常,出现分层现象,可能是两物种基因组杂合率较高所致。综上结果表明,太行菊、长裂太行菊均属于高重复、高杂合、大基因组的复杂基因组,建议使用Illumina+PacBio测序组装策略,进行全基因组测序分析。     

非人灵长类种群数量调查方法综述

监测估算野生动物的种群数量是保护的核心工作。由于气候变化和人类活动的影响,野生动物种群常处于不稳定的状态。非人灵长类是动物界的高等类群,具有复杂的社会行为、丰富的物种多样性,全球有701种 (含亚种),生活在多种类型的栖息地中,包括热带雨林、沼泽森林、红树林、次生林、落叶林、季雨林、山地森林,和包含孤存林、长廊森林、热带旱生林、山地草甸、地中海灌木林的稀树草原和干草原,以及荒漠、干旱的山地,甚至是雪地。绝大多数非人灵长类处于濒危的状态,长期有效的监测对于灵长类的保护十分重要。物种多样性和栖息地类型的多样性使得灵长类种群数量的调查方法多种多样。本文归纳总结了目前常用的非人灵长类种群数量调查方法的类型、基本原理、适用场景和局限性,并以研究实例加以分析;介绍了无人机、热成像、计算机学习系统等新技术应用在调查方法中的进展,希望为今后的非人灵长类野外数量调查、种群监测提供参考和启发。     

阻塞性睡眠呼吸暂停低通气综合征患者认知功能障碍现状调查及与生活质量的相关性研究

摘要 目的：调查阻塞性睡眠呼吸暂停低通气综合征（OSAHS）患者认知功能障碍的发生情况并分析其影响因素及与生活质量的相关性。方法：选取2019年5月至2021年5月我院收治的190例OSAHS患者,运用蒙特利尔认知评估量表（MoCA）评估其认知功能,并根据结果将患者分为正常组和认知障碍组。比较两组患者的多导睡眠监测（PSG）指标,采用单因素、多因素Logistic 回归分析OSAHS患者发生认知功能障碍的影响因素,比较两组患者的睡眠呼吸暂停生活质量指数（SAQLI）评分,采用Pearson相关系数分析MoCA评分与SAQLI评分的相关性。结果：190例OSAHS患者中有77例存在认知功能障碍,发生率为40.53%。认知障碍组患者的平均血氧饱和度（MSaO₂）低于正常组患者（P<0.05）。单因素分析结果显示,认知障碍组与正常组之间年龄、体育锻炼频率、受教育年限、体质量指数（BMI）比较有统计学差异（P<0.05）。多因素Logistic回归分析结果显示,年龄≥50岁、BMI≥28.0 kg/m²、受教育年限<9年、体育锻炼频率低于每周2次、MSaO₂<93%是OSAHS患者发生认知功能障碍的危险因素（P<0.05）。认知障碍组患者SAQLI三个维度（日常生活、社会交往、症状）的评分以及总分均低于正常组患者（P<0.05）。OSAHS患者的MoCA评分与日常生活、社会交往、症状评分以及SAQLI总分均呈正相关（P<0.05）。结论：OSAHS患者的认知功能障碍发生率较高,年龄、BMI、受教育年限、体育锻炼频率以及MSaO₂均是其影响因素,OSAHS患者的生活质量与认知功能呈正相关。     

Trends and Carrying Capacity of Sea Otters in Southeast Alaska

Sea otter populations in Southeast Alaska, USA, have increased dramatically from just over 400 translocated animals in the late 1960s to >8,000 by 2003. The recovery of sea otters to ecosystems from which they had been absent has affected coastal food webs, including commercially important fisheries, and thus information on expected growth and equilibrium abundances can help inform resource management. We compile available survey data for Southeast Alaska and fit a Bayesian state-space model to estimate past trends and current abundance. Our model improves upon previous analyses by partitioning and quantifying sources of estimation error, accounting for over-dispersion of aerial count data, and providing realistic measurements of uncertainty around point estimates of abundance at multiple spatial scales. We also provide estimates of carrying capacity (K) for Southeast Alaska, at regional and sub-regional scales, and analyze growth rates, current population status and expected future trends. At the regional scale, the population increased from 13,221 otters in 2003 to 25,584 otters in 2011. The average annual growth rate in southern Southeast Alaska (7.8%) was higher than northern Southeast Alaska (2.7%); however, growth varied at the sub-regional scale and there was a negative relationship between growth rates and the number of years sea otters were present in an area. Local populations vary in terms of current densities and expected future growth; the mean estimated density at K was 4.2 ± 1.58 sea otters/km² of habitat (i.e., the sub-tidal benthos between 0 m and 40 m depth) and current densities correspond on average to 50% of projected equilibrium values (range = 1–97%) with the earliest-colonized sub-regions tending to be closer to K. Assuming a similar range of equilibrium densities for currently un-occupied habitats, the projected value of K for all of Southeast Alaska is 74,650 sea otters. Future analyses can improve upon the precision of K estimates by employing more frequent surveys at index sites and incorporating environmental covariates into the process model to generate more accurate, location-specific estimates of equilibrium density. © 2019 The Authors. The Journal of Wildlife Management Published by Wiley Periodicals, Inc.     

Updated geographic range maps for giraffe,Giraffa spp., throughout sub‐Saharan Africa,and implications of changing distributions for conservation

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