Ground Cover—What Are the Critical Criteria and Why Does It Matter?

This publication is the result of concerns expressed regarding the definition and subsequent use of ground cover in rangeland monitoring. We reviewed 20 monitoring publications. All publications reviewed contained a definition of ground cover and/or direction on how to monitor ground cover. The majority of these publications also defined bare ground. In all cases, bare ground was defined as the opposite of ground cover.We identified critical criteria of ground cover based on the role it plays in soil conservation as it relates to water and wind erosion. Critical criteria identified included standing and nonstanding live vegetation, standing and nonstanding dead vegetation including litter, and rock. We compared these critical criteria to the 20 monitoring publications reviewed. We found 19 of these publications included the criteria standing live vegetation or similar words and standing dead vegetation or similar words in their definition and/or use of ground cover. The one source where standing live or dead vegetation or similar words were not included was “Indicators of Rangeland Health and Functionality in the Intermountain West.” This publication was produced by the US Department of Agriculture, Forest Service, Rocky Mountain Research Station. Ground cover was limited to basal vegetation, litter, moss/lichen, or rock. We also found inconsistencies in the definition and subsequent use of ground cover in Forest Service Handbook 2209.21–Rangeland Ecosystem Analysis and Monitoring Handbook, Intermountain Region.We contend a large volume of literature supports the inclusion of critical criteria as identified in this report as ground cover. These criteria are essential components contributing to resistance of water and wind erosion important to soil conservation. This review demonstrates the importance of accurately defining and subsequently including critical criteria in rangeland attributes including ground cover. This paper addresses standardizing terms and calculations used in determining ground cover.     

褐马鸡非损伤性取样、微量取样DNA提取的初步研究

褐马鸡是中国特有的国家Ⅰ级保护濒危鸟类,为了解决野生褐马鸡分子生物学研究中存在的取样局限性,采用非伤害性取样和非损伤性取样,对褐马鸡微量血液、皮、脚垫、指甲、羽毛、陈旧标本的皮以及粪便的DNA提取进行了初步研究。结果表明,从褐马鸡微量血液（10μL）中可以提取到浓度和纯度高的基因组DNA（41.85μg）;从褐马鸡的皮、脚垫、指甲、羽毛中可以提取出基因组DNA并扩增出目标片断;陈旧标本的皮能够提取到基因组DNA。该研究将拓宽褐马鸡分子生物学研究的采样范围,并可以提高野外非损伤性取样在保护遗传学中的应用。     

Sampling kiwis for mycoplasma infections

The set of animal health conditions under which ratites have been imported into New Zealand from Canada, Australia and the United Kingdom includes the provision that tracheal/ choanal and conjunctival swabs should be examined for the presence of mycoplasmas by culture, and that imported birds should be negative prior to export, and in post-arrival quarantine. Mycoplasma isolates of various species have been recovered from a number of groups of imported ostriches, both in pre-export isolation and in post-arrival quarantine.     

目标取样法和扫描取样法在圈养黑熊行为研究中的比较

应用目标取样法和扫描取样法同时对5只圈养黑熊(Ursus thibetanus)的15种行为进行了观察和记录,并对两种方法所得结果进行比较和讨论,评估两种方法在动物行为学研究中的可靠性。结果表明:两种方法所得的行为实际频次间存在显著差异(χ2=4.388,P=0.036,df=1),相对频次间无显著差异(χ2=0.468,P=0.494,df=1);行为持续时间的长短是影响两种方法所得结果间差异的主要因素,其与相对偏差值(Rela-tive Deviation,RD)之间存在显著的负相关关系(实际频次:r=-0.900,P=0.000,df=13;相对频次:r=-0.898,P=0.000,df=13);两种方法所得行为发生频次间存在显著正相关关系(r=0.965,P=0.000,df=13);扫描取样法所得行为间的差异性分析结果中70.5%与目标取样法的分析结果一致,29.5%存在分歧,且在分歧组中,参与差异性分析的两种行为的持续时间之差极显著大于一致组(χ2=10.082,P=0.001,df=1)。     

未加工畜禽产品的采样方法

食品分析的准确性是确定食品质量安全的最终保证,分析的准确性取决于食品固有特性和分析方法,食品固有特性包括食品的成分、结构以及微生物所致的成分结构的动态变化.     

Optimal Sampling Designs for Monitoring Plant Frequency

Plant frequency is a pragmatic surrogate for plant density in protocols designed for the long-term monitoring of diverse communities. Frequency estimates are based on presence/absence data from plots of fixed size, and plots are usually spatially aggregated into sites (often transects) to reduce field effort. Using a combination of statistical models and computer simulations, we identify sampling designs that maximize statistical power for detecting changes in underlying plant density based on the analysis of plant frequency. The optimal plot size for collecting frequency data decreases both with increasing spatial variation in local density (spatial structure) and with increasing numbers of plots per site. Over realistic ranges for these parameters, plots of optimal size yield mean frequencies that vary from 20% to 80%. However, with the exception of highly overdispersed populations, power is relatively insensitive to plot size; consequently, a plot size that yields a mean frequency of 50% usually provides nearly maximal power. For population monitoring, in which comparisons are made between successive samples from the same population, repeated measures from fixed sites improve statistical power substantially if there is spatial structure among sites, provided that the spatial pattern is at least partially consistent over time. However, there is still a power loss to the extent that the pattern of spatial structure among sites changes over time (a site-by-time interaction). This power loss can be mitigated by increasing the spacing between plots within sites, which has the effect of increasing the within-site structure and reducing the between-site structure. With more than 1 plot per site, there is no statistical advantage to obtaining repeated measures from fixed plots; relocating plots within sites in successive samples may therefore be advisable to minimize disturbance to the community.     

饲料产品的采样及实验室制备

<正>饲料分析的程序一般为:饲料的采样、制备和保存,样品的预处理、成分分析、分析数据处理及分析报告的撰写。所谓饲料采样就是从整批饲料的原料或成品中抽取具有一定代表性的样品。要正确采样,必须遵守两个原则:第一,采集的样品要均匀,有代表性,能反应全部被测饲料的组分、质量和卫生状况;第二,采样过程中要设法保持原有的理化指标,防止成分逸散或带入杂质。     

当前主要动物疫病监测抽样数量的探讨

应用流行病学理论,结合以往监测数据,建立相关模型,确定当前常规监测项目的采样数量。为动物疫病预防控制部门的科学监测提供参考。     

A Comparison of Liver Sampling Techniques in Dogs

Background

The liver sampling technique in dogs that consistently provides samples adequate for accurate histopathologic interpretation is not known.

Hypothesis/Objectives

To compare histopathologic results of liver samples obtained by punch, cup, and 14 gauge needle to large wedge samples collected at necropsy.

Animals

Seventy dogs undergoing necropsy.

Methods

Prospective study. Liver specimens were obtained from the left lateral liver lobe with an 8 mm punch, a 5 mm cup, and a 14 gauge needle. After sample acquisition, two larger tissue samples were collected near the center of the left lateral lobe to be used as a histologic standard for comparison. Histopathologic features and numbers of portal triads in each sample were recorded.

Results

The mean number of portal triads obtained by each sampling method were 2.9 in needle samples, 3.4 in cup samples, 12 in punch samples, and 30.7 in the necropsy samples. The diagnoses in 66% of needle samples, 60% of cup samples, and 69% of punch samples were in agreement with the necropsy samples, and these proportions were not significantly different from each other. The corresponding kappa coefficients were 0.59 for needle biopsies, 0.52 for cup biopsies, and 0.62 for punch biopsies.

Conclusion and Clinical Importance

The histopathologic interpretation of a liver sample in the dog is unlikely to vary if the liver biopsy specimen contains at least 3–12 portal triads. However, in comparison large necropsy samples, the accuracy of all tested methods was relatively low.     

北京市区流浪猫密度的初步抽样调查

城市中日益增多的流浪宠物正在成为一个困扰人们的问题。2006年3月至2006年5月，我们开展了北京市流浪猫的抽样调查，总计随机调查52个地点。这些调查地点分布于北京市五环内，一般每个调查地点调查1个样点，有4个地点调查了2个调查样点。调查样点以居民区为主。通过询问、样线调查等方式，获得了样点内流浪猫数量、繁殖情况和喂饲状况等数据。     

Sampling genotype configurations in a large complex pedigree

Many genetic problems can be solved by Monte Carlo method. This often requires sampling genotype configurations over pedigree. Current available samplers are inefficient for large animal pedigrees. A new sampler suitable for large complex pedigrees has been developed and evaluated. The sampler uses simple and iterative peeling algorithms alternately. The sampler was compared to two other samplers on hypothetical pedigree of 79 individuals and recessive disease. The behaviour of the sampler was evaluated in four experimental designs on real bovine pedigree of 907,903 animals. The application of the sampler was also exemplified in identical by descent study.     

动物疫病监测样本采集的注意问题

动物疫病监测在动物疫病防控中作用巨大,实验室检测是目前动物疾病监测的重要内容,特别是传染性疫病更离不开实验室检测,实验结果的准确性、有效性除实验方法、检测试剂、实验操作等因素影响外,从一开始就受到样本的采集、保存、运输等因素的影响.特别是在开展动物疫病的监测工作,监测结果是否具有代表性,是否能够真实反映出疫病的真实情况都与监测样本的采集有重要关系.规范化的样本采集与管理是质量控制动物疫病诊断、监测工作中至关重要的一环,关系到实验结果的准确性.动物疫病样本监测采集需要注意以下内容:     

采样对DHI测试结果的影响

一些牧场反映，对DHI测试出的数据产生怀疑。其实，不规范的采样方法，对测试的结果影响很大，特别在没有摇匀的情况下采样，就会出现同一头牛有不同的测试结果。对此，我们专门到牧场进行了一次采样试验，结果如下：     

兽医流行病学调查中的抽样方法概述

本文对兽医流行病学调查中常用的几种随机抽样和非随机抽样方法以及按规模大小成比例的概率抽样、基于风险的抽样进行了阐述,并结合文献报道的实例对每种抽样方法的优点、缺点和适用情况进行分析,以期为广大兽医工作者更好地开展流行病学调查和疫病防控工作提供支持。     

Sampling broiler house litter for coccidial oocysts.

1. A method of sampling the surface litter of commercial broiler houses for laboratory estimation of numbers of coccidial oocysts is described. 2. The resulting estimates can be regarded as indices of the total number of oocysts present in the house at the time of sampling. 3. Using material from a variety of sources it was shown that reliable estimates for many practical purposes can be achieved with few samples, unless the birds are less than 3 weeks old. 4. Oocyst numbers usually reached a peak 4 to 5 weeks after introduction of the birds and then rapidly declined in the next few weeks.