The evolution of virtual fences: A review

A virtual fence can be defined as a structure serving as an enclosure, a barrier, or a boundary without a physical barrier. The concept of virtual fencing occurs increasingly in discussions wherever free-ranging livestock is managed. It is especially interesting because of its potential to initially enhance ecological management, improve management by turning manual labour into cognitive labour as well as improve the life-style of livestock managers. All of these have the potential to reduce costs. Moreover, it opens up the possibility of managing areas that are not manageable at the moment. Therefore, a patent and literature search was conducted to investigate what virtual fencing involves, what opportunities there are for implementing it and what issues still need to be tackled. It was found that there are many different approaches in the development of virtual fencing, which can be split into three categories: first, to contain animals in a defined area or keep them out of a defined area using devices that are animal-borne; second, to contain animals without mounting a device onto the animal; and third, keeping animals apart with a moving fence line or using a virtual fence as a remote gathering device. The first two categories deal with static control of livestock, whereas the third category could be described as a control within moving boundaries. However, despite many patents having been found, only very few products are available on the market.Two important development areas are the energy use of the device and provision of a system that animals can easily understand, in order to assure welfare standards. The paper critically analyses the wide range of developments to date and points out the advantages and challenges virtual fencing offers. It also provides an indication of how far we are from a marketable product.     

兰坪云岭省级自然保护区生态质量评价研究

2010年4～7月,采用系统调查和资料收集相结合的方法,对兰坪云岭自然保护区的生物多样性进行了多学科考察,并对其生态质量进行了评价,结果表明:保护区植被可划分为9个植被型、12个植被亚型、21个群系,种子植物141科、608属、1 515种(含种下等级),哺乳动物80种,鸟类167种,两栖爬行类46种；保护区的生态质量...     

扎龙自然保护区大型土壤动物的群落结构

在扎龙国家自然保护区,选择了羊草、星星草、寸草苔和芦苇4种群落,对大型土壤动物生态特征进行了研究。研究结果表明,在四种群落中,共获得大型土壤动物75类,4359只,隶属于3门、7纲、21目、50科。优势类群是蚁科、棘跳虫科。大型土壤动物的类群数:芦苇群落=星星草群落>羊草群落>寸草苔群落,个体数:芦苇群落>星星草群落>羊草群落>寸草苔群落,寸草苔群落的生境条件最差,大型土壤动物的水平分布具有不均匀性;大型土壤动物的垂直分布基本都随土层深度的增加而递减,表现出明显的表聚性。大型土壤动物的季节动态表现为,类群数:夏季>秋季>春季;个体数:夏季>秋季>春季,春季不论是类群数还是个体数都是最低的。大型土壤动物的多样性表现为,寸草苔群落=星星草群落>芦苇群落>羊草群落。     

长白山自然保护区道路影响域土壤Zn和Pb分布及污染分析

分别在长白山自然保护区北坡的阔叶红松林、针叶林和岳桦林等3种森林中不同利用强度的6个路段,垂直于道路设置长50 m、宽10 m采样断面,在距路基4、12、20、28、40和48 m随机采集表层0~20 cm土壤,利用ICP-ES测定土壤样品中Zn和Pb的含量。研究不同森林类型、不同利用强度道路50 m路域范围土壤重金属含量、分布特征和污染状况。结果表明:随道路利用强度增强,在阔叶红松林和岳桦林带,路域50 m范围土壤Zn和Pb含量增加明显;在针叶林带,路域50 m范围土壤Pb含量增加明显;随道路利用强度增强,Pb在阔叶红松林带路域土壤中积累范围为12~28 m,在针叶林带路域中积累范围为20~40 m,在岳桦林带路域0~50 m范围积累都明显;与阔叶红松林带土壤相比,岳桦林带路域土壤Pb含量变化对道路产生的Pb污染更敏感;利用强度强的岳桦林带路域土壤Zn和Pb的污染分指数最大,分别为1.49和1.52,都为轻度污染。     

Responses of Soil Acid Phosphomonoesterase Activity to Simulated Nitrogen Deposition in Three Forests of Subtropical China

Soil acid phosphomonoesterase activity(APA)plays a vital role in controlling phosphorus(P)cycling and reflecting the current degree of P limitation.Responses of soil APA to elevating nitrogen(N)deposition are important because of their potential applications in addressing the relationship between N and P in forest ecosystems.A study of responses of soil APA to simulated N deposition was conducted in three succession forests of subtropical China.The three forests include a Masson pine(Pinus massoniana)forest (MPF)-pioneer community,a coniferous and broad-leaved mixed forest(MF)-transition community and a monsoon evergreen broad-leaved forest(MEBF)-climax community.Four N treatments were designed for MEBF:control(without N added),low-N(50 kg N ha^-1 year^-1),and medium-N(100 kg N ha^-1 year^-1)and high-N(150 kg N ha^-1 year^-1),and only three N treatments(i.e.,control, low-N,medium-N)were established for MPF and MF.Results showed that soil APA was highest in MEBF,followed by MPF and MF.Soil APAs in both MPF and MF were not influenced by low-N treatments but depressed in medium-N treatments.However,soil APA in MEBF exhibited negative responses to high N additions,indicating that the environment of enhanced N depositions would reduce P supply for the mature forest ecosystem.Soil APA and its responses to N additions in subtropical forests were closely related to the succession stages in the forests.     

多种遥感分类方法提取冰川边界探讨

综合目视解译和计算机自动解译的方法,将冰川解译的传统方法及面向对象图像特征提取方法应用于喀纳斯河源的冰川边界提取中,并对提取出的单条冰川逐一分析。研究发现：面向对象的图像特征提取方法能较好的提取具有特征类型的地物;目视解译的方法虽然费时费力,但适用于任何类型冰川的提取;传统比值阈值、雪盖指数法、监督分类与非监督分类在无表碛覆盖,积雪覆盖较少的纯冰区效果明显。对阿尔泰山喀纳斯河源区的40条冰川进行解译,对多种方法进行比较,得到喀纳斯河源地区精确的冰川边界。结果表明：喀纳斯河源区冰川总体上呈退缩趋势,1959-2011年冰川面积共减少了23.43 km²。     

小陇山国家级自然保护区油松群落生态位研究

文中采用样方调查法,对研究区内油松群落中主要种群的Shannon-Weinner多样性指标及Lev-ins生态位宽度、生态位重叠值和生态位相似比例等进行了分析。结果表明:1)油松群落中油松的生态位宽度最大为0.9827,槲树的生态位宽度最小为0.1582;2)优势种油松与其他物种的生态位重叠值在0.06～0.1之间,反之在0.01～0.05之间,说明油松群落的生态位重叠值不大,群落中因利用相同的资源位而产生的种间竞争并不激烈,是一个稳定的森林群落;3)生态位相似比例大于0.5的有9对,占20%,其物种间生态位相似比例值一般较低,反映其主要物种利用资源的相似程度较小。但是生态位宽度较大的物种之间的生态位相似性比例仍较高,如油松与甘肃山楂、锐齿栎的生态位相似性比例分别为0.5209、0.5320。     

老秃顶子保护区水源林主要乔木树种种间关系

在群落调查的基础上,应用χ2检验、Ochiai关联度指数、Pearson相关分析和Spearman秩相关分析,研究了老秃顶子自然保护区水源涵养林群落内16种主要乔木树种的种间联结性和相关性。结果表明,所有种对中,多数种对间关联程度为不显著水平,呈极显著相关和显著相关的种对数相对较少,表明群落内多数乔木树种间关系较松散,未形成明显的总体关联性,群落处于相对稳定状态;种间关系分析中,χ2检验、Ochiai关联度和Pearson相关分析的结果比Spearman秩相关分析结果的灵敏度要低;根据分析结果,结合乔木种群的生物学和生态学特征,可将老秃顶子保护区水源林群落中16种主要乔木树种划分为3个生态种组,同一生态种组内物种的生态要求和资源利用方式相近,联结紧密,而不同种组间联结较为松散。     

山东南四湖省级自然保护区野生鸟类调查及疫源疫病防控初探

旨在通过对山东南四湖自然保护区野生鸟类种类、数量、居留型和群落多样性进行调查,以期为野生鸟类调查及疫源疫病监测奠定数据基础。2018—2021年采用样线法和直接计数法对山东南四湖自然保护区内鸟类进行监测调查,共记录到鸟类15目43科129种,数量34700只。其中国家Ⅰ级重点保护野生动物3种为青头潜鸭(Aythya baeri)、白鹤(Grus leucogeranus)、东方白鹳(Ciconia boyciana),Ⅱ级重点保护野生动物12种。监测种类最多的为雀形目(Passeriformes)共74种,占比57.36%;监测数量上鹤形目最多(47.40%),其次为雀形目(30.02%),雁形目(16.57%);优势种为白骨顶(Fulica atra)、红头潜鸭(Aythya ferina)、白鹭(Egretta garzetta),麻雀(Passer montanus)。鸟类构成以迁徙鸟为主,春、夏季鸟类群落多样性指数最高;鱼塘湿地生境的多样性指数和均匀度指数均最高,自然水域最低。本研究获得了区域内野生鸟类生物多样性基础资料,为未来野生鸟类调查和疫源疫病监测奠定坚实基础。     

赣江源自然保护区生态系统服务价值评估

赣江源自然保护区位于赣南山地丘陵生态区,其森林覆盖率高达94.2%,主要功能是水源涵养、水土保持与水质保护。本文使用市场价值法、影子工程法和替代花费法等方法,对保护区各植被类型的保持土壤、涵养水源、调节气候、净化环境、生物多样性保育等5项生态功能进行了货币化估算,得出保护区森林生态系统总价值约为8.8亿元。应加强保护自然保护区内的阔叶林,合理开发利用竹林。