The increasing trend of large carnivore attacks on humans not only raises human safety concerns but may also undermine large carnivore conservation efforts. Although rare, attacks by brown bears Ursus arctos are also on the rise and, although several studies have addressed this issue at local scales, information is lacking on a worldwide scale. Here, we investigated brown bear attacks (n = 664) on humans between 2000 and 2015 across most of the range inhabited by the species: North America (n = 183), Europe (n = 291), and East (n = 190). When the attacks occurred, half of the people were engaged in leisure activities and the main scenario was an encounter with a female with cubs. Attacks have increased significantly over time and were more frequent at high bear and low human population densities. There was no significant difference in the number of attacks between continents or between countries with different hunting practices. Understanding global patterns of bear attacks can help reduce dangerous encounters and, consequently, is crucial for informing wildlife managers and the public about appropriate measures to reduce this kind of conflicts in bear country.

Past hunter-gatherer societies are often perceived as having co-existed harmoniously with their environment. In reality, few ecosystems remain unaltered following the arrival of humans and the relationship between people and wildlife over the past thousand years is characterised more by conflict than harmony. Over this period, many industrialised countries, particularly in Europe, have seen a substantial loss of natural habitats, in parallel with huge increases in human populations. England is one such country; here, the human population is estimated to have increased 45-fold since 1066 AD. Over the past 50 years, however, many of these countries have witnessed a change in public attitudes, leading to ‘protective’ legislation for species and habitats, with the subsequent recovery of at least some species. As a result, some people now argue that certain species are ‘over-protected’, leading to calls to remove protection. We review how the regulatory system in England is used to achieve a sustainable balance between wildlife and human interests, illustrated with examples from key areas of conflict. In all, more than 8000 licences permitting activities affecting protected species are issued in England each year, about half of which concern human–wildlife conflicts, including almost 1000 aimed at preventing serious damage by wildlife. We estimate that wildlife licences are relied on by more than 100 000 people to resolve human–wildlife conflicts. In most cases, less than 1% of a species’ population is likely to be affected by regulated activities and, where this is not the case, thresholds are set to ensure the control measures do not lead to the long-term detriment of populations. We conclude by suggesting how the legislative framework may need to adapt to deliver modern aspirations to reconcile human and wildlife interests.

Tigers are critically endangered due to deforestation and persecution. Yet in places, Sumatran tigers (Panthera tigris sumatrae) continue to coexist with people, offering insights for managing wildlife elsewhere. Here, we couple spatial models of encounter risk with information on tolerance from 2386 Sumatrans to reveal drivers of human-tiger conflict. Risk of encountering tigers was greater around populated villages that neighboured forest or rivers connecting tiger habitat; geographic profiles refined these predictions to three core areas. People's tolerance for tigers was related to underlying attitudes, emotions, norms and spiritual beliefs. Combining this information into socio-ecological models yielded predictions of tolerance that were 32 times better than models based on social predictors alone. Preemptive intervention based on these socio-ecological predictions could have averted up to 51% of attacks on livestock and people, saving 15 tigers. Our work provides further evidence of the benefits of interdisciplinary research on conservation conflicts.

Wild ungulates are an important part of terrestrial ecosystems and play a critical role in maintaining ecosystem health and integrity. In many grassland ecosystems that are habituated by wild ungulates, the coexistence of domestic ungulates has created a conflict over grazing resources. Solving this conflict requires a balanced and sustainable policy that satisfies both the needs of wildlife protection and food production. Here, we assess the optimal grassland livestock carrying capacity of an alpine grassland on the Qinghai-Tibet Plateau, given the coexistence of wild populations of kiangs (Equus kiang) and Tibetan gazelles (Procapra picticaudata), two key species grazing in this region. We use kriging and the MaxEnt method to estimate the population sizes of kiangs and Tibetan gazelles in Maduo County, Qinghai Province. We then convert the estimated population size of the two species into sheep units and calculate the residual carrying capacity for livestock grazing. We show that after accounting for the grazing need for kiangs and Tibetan gazelles, grassland in Maduo is capable of supporting 420,641 sheep units, which is slightly more than the current livestock population. However, the residual carrying capacity is highly uneven across the region, and overgrazing is found in many areas of Maduo, especially in northern Maduo. This research provides a useful framework for planning sustainable livestock farming for the Qinghai-Tibet Plateau and other regions facing wildlife-livestock conflict.

三江源国家公园地处青藏高原腹地，是国家重要的生态资源资产区，生态战略地位十分突出。本研究选择黄河源园区3种典型高寒草原，测定不同季节牧草的养分供给状态并计算家畜承载力，为实现黄河源园区草畜平衡提供数据支撑。结果表明：不同季节的植被数量特征、牧草营养特征和承载力表现为：紫花针茅(Stipa purpurea)草原和垂穗披碱草(Elymus nutans)草原显著高于冷地早熟禾(Poa crymophila)草原；从生态保护的角度出发，紫花针茅、垂穗披碱草和冷地早熟禾草原盛草期的家畜承载力分别为1.72 SHU·hm^-2，1.41 SHU·hm^-2和1.18 SHU·hm^-2；枯草期的家畜承载力分别为0.35 SHU·hm^-2，0.34 SHU·hm^-2和0.10 SHU·hm^-2。综上所述，紫花针茅草原可以为黄河源园区提供更多的牧草养分。结合放牧家畜对牧草的营养需求，建议根据牧草产量和营养的季节动态，优化草畜资源空间配置。

Sanjiangyuan National Park is an important national ecological resource asset area with prominent ecological strategic position,which is located in the hinterland of the Qinghai-Tibet Plateau. In this study,three typical alpine grasslands in the Yellow River Source Park were selected to determine the nutrient supply status of forage in different seasons and calculate the livestock carrying capacity to provide the supporting data for realizing the balance of grass and livestock in the Yellow River Source Park. The results showed that the quantitative characteristics of vegetation,herbage nutritional characteristics and carrying capacity in different seasons were as follows:<i>Stipa purpurea</i> grassland and <i>Elymus nutans</i> grassland were significantly higher than <i>Poa crymophila</i> grassland;From the perspective of ecological protection,the livestock carrying capacity of <i>Stipa purpurea</i>,<i>Elymus nutans</i> and <i>Poa crymophila</i> grassland were 1.72 SHU&#183;hm^-2,1.41 SHU&#183;hm^-2 and 1.18 SHU&#183;hm^-2,respectively,during the flourishing period;0.35 SHU&#183;hm^-2,0.34 SHU&#183;hm^-2and 0.10 SHU&#183;hm^-2,respectively,during the withering period. To sum up,<i>Stipa purpurea </i>grassland could provide more forage nutrition for the Yellow River Source Park. Combined with the nutritional needs of grazing livestock for forage,it recommended that the spatial allocation of forage and livestock resources should be optimized according to the seasonal dynamics of pasture production and nutrition.

以黄河源区玛多县为研究区域,利用无人机遥感技术调查了县域内藏野驴、藏原羚、岩羊等大型野生食草动物和家畜的种群数量,利用降尺度算法生成了2016年玛多县30 m空间分辨率的产草量数据,在此基础上估算了包括野生动物和家畜在内的草畜平衡状况,分析了大型野生食草动物对玛多县草畜平衡的影响。结果表明:1)通过飞行样带内种群密度,推算了玛多县内大型食草动物种群数量,分别与统计数据、暖季调查结果对比验证,估算出2017年冷季藏野驴、藏原羚和岩羊分别为1.71、1.60和0.93万匹(只),家牦牛、藏羊和马分别为7.08、10.22、0.12万头(匹、只),大型野生食草动物和家畜总计47.5万羊单位,大型野生食草动物羊单位数量与家畜羊单位数量之比为1&#x02236;4.5;2)仅考虑饲养家畜,载畜压力指数为1.13,表明草地略微超载;在综合考虑饲养家畜和野生动物的情况下,载畜压力指数为1.38,表明草地中度超载;3)若没有将大型野生食草动物纳入草畜平衡核算体系内,载畜压力将被低估22%。超载过牧是造成玛多县草地退化一个主要驱动因素,需人工补饲7.90万t干草或减畜30%才能维持草畜平衡。

The number of wild large herbivores, including <em>Equus kiang</em>, <em>Procapra picticaudata</em> and <em>Pseudois nayaur</em> was investigated using remote sensing technology or an unmanned aerial vehicle (UAV). The balance of grassland-livestock, including wild and domestic herbivores, was estimated from data (30 m resolution) in Maduo County in 2016 and the effects of wild herbivore population on the balance of grassland-livestock analyzed. The population of large herbivores was estimated from animal density from sample flights, and the results compared with data from summer monitoring. The estimated number of <em>E. kiang</em>, <em>P. picticaudata</em> and <em>P. nayaur</em> were 1.71, 1.60 and 0.93 million respectively, while the number of yak, Tibetan sheep and horses were 7.08, 10.22 and 0.12 million respectively. The number of large wild herbivores present was equivalent to 47.5 million sheep stock units. The ratio of sheep stock units from wild herbivores to the number of domestic herbivores was 1&#x02236;4.5. The carrying capacity index of domestic livestock was 1.13, indicating that the grassland was slightly overstocked; the carrying capacity index for wild herbivores was 0.25 and the combined carrying capacity index (1.38) indicated that the grassland was overstocked. Not including wild herbivores in the grassland-livestock balance accounting system resulted in the carrying capacity index being underestimated by 22%. Overstocking is one of the main drivers of grassland degradation in Maduo County; feeding of 79000 tons of hay or reducing livestock numbers by 30% would be required to achieve balance.

随着自然保护事业的发展,人与野生动物冲突加剧成为自然保护与地区发展面临的新问题。但人与野生动物冲突研究具有多主体性、复杂性和跨学科性,研究难度大。本文以羌塘高原为例,采用人与野生动物相互作用社会生态系统的概念,梳理了人与野生动物冲突主体的规模、分布,识别了食草野生动物与家畜争食牧草、人类聚落与野生动物竞争生存空间、草场围栏分隔栖息地及阻断迁徙通道等三种主要冲突类型。考虑草畜兽平衡核算了草地承载状况,模拟了家畜与野生动物生存空间重叠,刻画了草场围栏对栖息地及迁徙通道的影响。从重叠空间的资源竞争及人类活动扰动等方面剖析了人与野生动物冲突成因。可为厘清冲突机制,提高干预效果提供新认知。

With the great progress of nature conservation in the last decades, human-wildlife conflict (HWC) has emerged as a new issue regarding protected areas. It is important to understand the causes for HWC and take effective measures to reduce HWC. However, research on HWC, characterized by systematicity, complexity, composed by multi-agents, and having feedback mechanism among agents, is difficult for us. Taking the Changtang Plateau in Tibet as an example, with the concept of social-ecological system of human-wildlife interactions, the distribution and quantity of agents of HWC is illustrated by field survey, statistical data and remote sensing data. Three main types of HWC in the study area is identified: (1) Forage competition between domestic livestock (sheep, goats and domestic yak) and herbivore wildlife (<em>Pantholops hodgsonii</em>, <em>Equus kiang</em>, <em>Procapra picticaudata</em>, <em>Gazelle</em>); (2) Living space competition between human settlements and wildlife habitats; (3) Fence separated the pasture and blocked the migratory routes of wildlife like Tibetan antelope. The pasture carrying capacity is examined by integrating wildlife with domestic livestocks. The overlaying of grazing pasture with wildlife habitat was modelled with the Maxent niche model and analyzed with the aid of GIS (geographic information system). Carrying capacity rate including both domestic livestock and herbivore wildlife was 110%, while domestic livestock stock rate was only 98%. Spatial overlapping rate was more than 50% for Tibetan antelope and domestic livestock. The impact of fence on habitat and migratory route of wildlife is also analyzed. Finally, causes for HWC are assembled from the aspects of the resource competition, the overlaying of living space, and the disturbance from human activities such as fence. The study is helpful to clarify the HWC cause and formation mechanism, and to improve the performance of conflict reduction measures.

在黄河源区-青海省果洛藏族自治州玛沁县选取4个不同退化程度的天然草地,以围栏内封育和围栏外自由放牧草地作比较,采用样方法调查草地围栏内外的群落结构特征和草地初级生产力生物量,并通过计算地上与地下生物量比值以及植物群落干鲜比来评价围栏封育的效果。结果表明:不同退化程度围栏内外的植被组成存在显著差异;随着退化程度的加剧,植物群落的盖度、高度以及多样性指数有下降趋势,且围栏内的盖度、高度及多样性指数均大于围栏外的;植物群落高度、盖度、地上生物量和生物量干鲜比随着退化程度加剧有减小的趋势。围栏封育有利于改善青藏高原退化高寒草地的植物群落结构,提高草地植物群落的盖度和生物量,促进其恢复演替。

The plant community structure and primary production of the alpine grasslands under different degradation degrees were investigated in Maqin County of Qinghai Province,the headwater area of Yellow River.The structure of the plant community had significant variation relating grassland degradation with fencing.The coverage and height of plants inside fences were higher than those outside fences and declined with the increase of degradation degrees.Similar results were found for the plant diversity index.The aboveground biomass,coverage and height of the grassland along degradation gradients showed a declining trend.These parameters were significantly higher in the fenced grasslands than the unfenced ones.Aboveground biomass/underground biomass ratios of the grassland were decreased by degradation and increased by fencing.The ratios of dry to fresh weight of aboveground biomass declined with the increase of degradation degree and increased after fencing.It can be concluded that grassland enclosure is a feasible approach to restore grassland vegetation in the headwater areas of the Qinghai-Tibetan Plateau.Plant cover,plant biomass and species biodiversity can be used as indicators to assess grassland restoration intervention.

本文针对国家资源环境承载能力监测预警评估中生态承载力评估的需求,探讨了生态承载力及预警的定义与内涵,从预警角度提出区域生态承载力评价的内容与方法,并以京津冀地区为例开展了案例研究。主要结论为：生态承载力是指生态系统提供服务功能、预防生态问题、保障区域生态安全的能力。生态承载力预警评估的实质是评估人类活动是否及在多大程度上影响生态系统在水源涵养、水土保持、防风固沙等主要服务功能的提供,是否产生了生态环境问题,是否影响到区域的生态安全。其评价流程主要包括：区域生态承载力评价指标选取及评价方法和阈值的确定、生态承载力预警状况及变化趋势分析、成因解析等内容。本文提出的生态承载力预警评价的方法及案例,可为全国及区域生态承载力的评估提供基础。

Based on the national needs for resources and environment carrying capacity monitoring and early-warning, this article addresses the definition of ecological carrying capacity and its evaluation method for early-warning. A case study was carried out for the Beijing-Tianjin-Hebei region. The article concludes that ecological carrying capacity refers to the ability of ecosystems in providing ecosystem services, preventing ecological problems, and ensuring ecological security. Ecological carrying capacity evaluation for early-warning is to examine the extent of human disturbances that affect ecosystem services supply with regard to water retention, soil retention, sandstorm prevention; produce ecological problems; and affect regional and national ecological security. The main procedures involve indicator and evaluation method selection, threshold identification, status and trend analysis of ecological carrying capacity with reference to early-warning threshold, and cause analysis. The method and case study of ecological carrying capacity evaluation for early-warning proposed in this study can serve as a basis for regional and national assessment.

为探究道路对三江源国家公园黄河源园区藏野驴（Equus kiang）和藏原羚（Procapra picticaudata）种群数量及其栖息地的影响，于2020年冷季采用截线取样法在黄河源园区进行实地调查。通过设置4种不同等级的道路情景，使用MaxEnt模型评价藏野驴和藏原羚的生境适宜性，模拟了不同等级道路变量情景下两种有蹄类动物的适宜栖息地。并根据适宜栖息地面积和R程序的Distance包估算了藏野驴和藏原羚种群密度及数量。结果显示，调查样线总长1 320.63 km，发现藏野驴2 231头，藏原羚822只。估算藏野驴的种群密度为每平方千米（1.18 &#177;0.34）头，种群数量为2 400~7 632头；藏原羚的种群密度为每平方千米（0.94 &#177;0.14）只，种群数量为1 765~3 219只。MaxEnt模型预测结果表明，藏野驴和藏原羚适宜栖息地面积分别为3 641.34 km2和2 525.18 km2，分别占整个黄河源园区的19.2%和13.3%。影响藏野驴分布的主要环境因子依次为：距低等级公路的距离、年降水量、海拔和归一化植被指数。影响藏原羚分布的主要环境因子依次为：距低等级公路的距离、海拔、坡向和坡度。两种有蹄类动物重叠的适宜栖息地面积为2 240.15 km2，分别占藏野驴适宜栖息地的61.5%和藏原羚适宜栖息地的88.7%，且二者的适宜栖息地主要分布在黄河源园区的中部。不同道路情景模拟结果显示：（1）相比于不含道路变量的情景，道路存在的3种情景会使两种有蹄类动物的栖息地出现不同程度的丧失，种群数量也随之出现不同程度的下降。不含道路变量的情景时，两种有蹄类动物适宜生境面积最大，种群数量也最大；含全部道路变量的情景时，两种有蹄类动物适宜生境面积最小，种群数量也最小，栖息地丧失的比例最大，分别为27.2%和42.3%。（2）不同等级道路对二者的栖息地面积和种群数量影响程度不同，与高等级公路相比，低等级公路会使两个物种丧失更大的栖息地面积，种群数量下降更多。（3）两个物种对道路干扰的响应不同，在不同道路情景下，藏原羚会丧失更大比例的栖息地面积，种群数量下降幅度更大。本研究通过量化评估不同等级道路对有蹄类动物栖息地和种群数量的影响，为高原有蹄类物种的保护与道路的管理规划提供科学依据。

We sought to understand the effects of roads on the populations and habitat of Tibetan wild ass (Equus kiang) and Tibetan gazelle (Procapra picticaudata) in the Yellow River Source Zone of Sanjiangyuan National Park. We conducted a field survey to estimate population size, density and distribution of Tibetan wild ass and Tibetan gazelle in the region in autumn 2020 using a line transect sampling method. We then used the MaxEnt to assess habitat suitability of the two species under four different scenarios of road density and road type. The total length of the survey line was 1 320. 63 km, along which 2 231 Tibetan wild asses and 822 Tibetan gazelles were observed. The density of Tibetan wild ass was (1. 18 &#177;0. 34) individuals/km2 and the estimated abundance ranged from 2 400 to 7 632. The density of Tibetan gazelle was (0. 94 &#177;0. 14) individuals/km2 and the estimated abundance ranged from 1 765 to 3 219. MaxEnt predicted that the suitable habitat areas of Tibetan wild ass and Tibetan gazelle were 3 641. 34 km2 and 2 525. 18 km2, accounting for 19. 2% and 13. 3% of the entire Yellow River Source Zone, respectively. Distance to low-grade roads, annual precipitation, altitude and normalized difference vegetation index were the most important factors affecting habitat suitability for Tibetan wild ass.Distance to low-grade roads, altitude, aspect and slope were the most important factors affecting habitat suitability for Tibetan gazelle. The overlapping suitable habitat area of the two species was 2 240. 15 km2, accounting for 61. 5% and 88. 7% of the suitable habitat of Tibetan wild ass and Tibetan gazelle, respectively. The suitable habitats of Tibetan wild ass and Tibetan gazelle in autumn were mainly distributed in the central part of the Yellow River Source Zone. The road scenarios analysis indicated that:(1) the three scenarios including road variables resulted in varying degrees of habitat area loss and consequent population declines for both species when compared to the scenario with no roads. Scenarios with all road variables resulted in the smallest area of suitable habitat and the smallest populations for both species with 27. 2% and 42. 3% of suitable area lost for Tibetan wild ass and Tibetan gazelle respectively. (2) Different types of roads have different degrees of influence on the habitat area and populations of the two species. Low-grade roads cause greater habitat area loss and greater population declines for both species compared to highgrade roads. (3) The two species respond differently to road disturbance, with Tibetan gazelle suffering a greater loss of suitable habitat and experiencing a greater reduction in population size. This study provides evidence for ungulate conservation and roads managed on the Qinghai-Tibetan Plateau by quantitatively assessing the effects of different types of roads on the habitats and populations of two ungulate species.

As a typical representative of the herbivorous wild animals in Chang Tang Plateau, the number of Tibetan wild asses has increased significantly in recent years. Clarifying the distribution, population, and size of its habitats is conducive to formulating the protection plan for wild animals and managing the conflict between people and wild animals in Chang Tang Plateau. Based on the distribution probability of Tibetan wild ass habitats and environmental factors, the number of Tibetan wild asses in Gaize County of Chang Tang Plateau was calculated by using the belt transect method and random forest model, and due to the uncertainty of the calculations, the results were corrected and analyzed. The results show that the living environment of Tibetan wild asses in Gaize County of Chang Tang Plateau is at 4400-4600 m above sea level, 350-400 m away from the river, and the average temperature in the warmest season is 10-12 ℃. The vegetation types of habitats are generally temperate tufted dwarf grass, dwarf semi shrub desert grassland, alpine grass, Carex grassland, alpine cushion dwarf semi shrub desert, among others. On the basis of studying the environmental preferences of Tibetan wild asses, the random forest model was corrected by using the data of the second scientific survey sample line of Qinghai-Tibet Plateau for three years. The approximate number of Tibetan wild asses in each of the different areas of Gaize County was obtained. The number of Tibetan wild asses in Gaize Town, Xianqian Township, Gumu Township, Chabu Township, Mami Township, Wuma Township and Dongcuo Township is 855, 3458, 2358, 1453, 743, 943 and 647, respectively. By studying the environmental preferences of Tibetan wild asses and analyzing the results of the belt transect survey, the random forest model can accurately estimate the number of Tibetan wild asses in Gaize County of Chang Tang Plateau.

尽管精度(或总体错分率)普遍用作分类算法的性能评价指标，但存在诸如敏感于类先验分布和错分代价，忽略分类算法所得的后验概率或排序信息等不足。而接收者操作特性(ROC)曲线下面积则能度量算法在整个类先验分布及错分代价范围内的总体分类性能、后验概率和排序性能，因此在分类学习中受到越来越多的关注，由此涌现出众多研究成果。文章旨在对此作相对全面的回顾和总结，包括AUC作为性能评价指标的优势所在，基于AUC优化的算法设计，基于精度优化和AUC优化的算法间的关系以及AUC存在的不足及改进。

Though as a common performance evaluating index for classification algorithms, accuracy (or total misclassification error) has several deficiencies, such as the sensitivity to class prior distribution and misclassification costs, and the ignorance of the posterior probability and ranking information obtained by classification algorithms. While the area under the receiver operation characteristic (ROC) curve measures the classification performance across the entire range of class prior distribution and misclassification costs, as well as the probability and ranking performance. Thus, it attracts much attention in classification learning and evokes a lot of researches. In this paper, a relative comprehensive survey for these researches is presented, including the advantages of AUC as a performance evaluating index, the design of algorithms based on AUC, the relationship between the accuracy-maximizing and AUC-maximizing algorithms and the deficiencies of AUC along with its variants.

Humans and domestic species far outweigh other mammals.