评估不同尺度下农牧地对滇金丝猴景观连接度的影响

基于图论法原理,综合最小费用距离和猴群的最小家域,建立了滇金丝猴栖息地的潜在扩散廊道及廊道缓冲区。在此区域内,根据遗传距离与栖息地连接最小费用距离的相关性,确定了5个不同管理单元间猴群可能扩散的阈值,并根据此阈值计算获得可能连通性指数(PC)去评估不同尺度下农牧地对滇金丝猴栖息地景观连接度的影响。结果表明:在距离为2.15km的廊道缓冲区范围内,5个不同管理单元间猴群可能扩散的最小费用距离阈值为1600,在两个斑块之间的费用距离小于或等于1600时,两个斑块能够连接,猴群可能在这两个斑块进行扩散,超过费用距离1600时,两个斑块不再连接,即猴群在这两个斑块间不会扩散。景观尺度下,PC指数逐渐增加,意味着未来4种不同的农牧地改善情景(C1,C2,C3,C4)都将促进景观连接度的增加;在斑块尺度下,通过确定出的最佳距离阈值,将整个研究区域分成不同的组分,小于或等于阈值的相邻斑块被划分在同一个组分中,大于阈值则不在一个组分中,研究区域中的5个不同管理单元间的猴群被划分在3个不同的组分中,情景C1,C2中组分数量没有变化,意味着连接度没有发生改变,但在情景C3,C4中,组分数量减少,并与相邻的组分融为一个组分,意味着连接度发生改变,滇金丝猴的活动范围扩大,更有利于猴群的基因交流。研究结果将为滇金丝猴栖息地的保护、未来廊道的恢复建设提供科学依据,同时也能为类似的研究提供方法上的参考。     

基于生境斑块的滇金丝猴景观连接度分析

基于生境斑块,结合最小费用距离并运用图论法对滇金丝猴分布区进行栖息地连接度分析,研究利用猴群的现实分布结合Logistic回归模型确定了景观功能连接的最佳距离阈值,对于功能畅通的组分,以景观指数BC定量识别出作为"踏脚石"的优先保护区域;对于功能不连接的组分,绘制出最小费用路径,确定了该路径中优先恢复区域。结果表明:最佳的最小费用距离阈值为1400,该阈值下猴群主要存在于5个组分中,所有组分中猴群间的连接度优劣排序为组分3组分1组分5组分4,龙马山猴群(G15)没有"踏脚石"斑块使其与同一组分内的其他猴群相连接,应考虑优先恢复该区域的植被,研究成果对于该物种的保护和其他濒危物种的类似研究具有较强的参考价值和借鉴意义。     

基于电路理论的滇金丝猴生境景观连通性分析

景观连通性对生态系统服务、动植物基因交流的保护以及景观规划等都具有重要影响作用。以滇金丝猴活动区域为研究对象,基于电路理论建立滇金丝猴栖息地的连接度模型,分析滇金丝猴栖息地间的连通性,对于连通性较好的区域,识别出了重点保护与恢复区域;对于连通性较差的区域,通过电路理论连接度模型确定了影响今后廊道建设的重点保护与恢复区域。结果表明:各区域内部猴群栖息地连通性较好,其中中部地区最优,其次是北部,最差为南部。G3和G4栖息地斑块作为对连接各区域猴群生境斑块起到关键作用的"踏脚石"斑块是今后重点保护与恢复的区域,保护和恢复南部与中部猴群栖息地间"空白区域"的植被对于整个滇金丝猴活动区域的猴群基因交流也尤为重要。方法上,相较于图论得到的单一路径,电路理论得到的多路径更具有现势性。研究方法及研究成果可为濒危物种保护和区域生态廊道设计提供重要参考价值。     

人为干扰对神农架川金丝猴连通性及遗传多样性的影响

川金丝猴湖北种群是川金丝猴分布的最东缘,现主要分布于神农架国家公园和巴东自然保护区,其作为单独的管理单元,相对较低的遗传多样性、孤立的遗传状态和较小的种群数量,使得该种群面对环境变化脆弱性高。以神农架为研究区域,首先基于物种分布模型获得川金丝猴移动的阻力图层,利用电路理论分析适宜生境连接度;其次,设置道路和旅游两个人为干扰情景,运用最小费用距离模型与电路理论模型,分析道路和旅游活动对川金丝猴移动路径以及对不同亚群内和亚群间连通性的影响;最后,利用CDPOP软件模拟道路对川金丝猴遗传多样性的影响。结果表明:(1)神农架川金丝猴适宜生境分布较集中,生境斑块间存在多个潜在扩散区域;(2)道路改变了川金丝猴往来于南北生境间的最优路径,旅游干扰对川金丝猴移动路径无明显影响,其干扰主要在于川金丝猴对其具有回避性,回避距离为100 m;(3)道路显著降低金猴岭亚群内的连通性,并显著增加了所有亚群间的移动阻力,旅游活动对亚群内和亚群间的连通性无显著影响;(4)川金丝猴种群在150年内的遗传多样性呈下降趋势,道路的影响将加剧遗传多样性下降的程度。基于以上结果本文提出了针对性的保护建议,对于该物种的保护和其他濒危物种的类似研究具有较强的参考价值和借鉴意义。     

滇金丝猴现状及研究进展

野外滇金丝猴目前仅存于金沙江和澜沧江间云岭山脉的一个狭小区域,种群大小约1 700只左右.面临着栖息地高度破碎化、较为猖狂的盗猎活动和日益严重的放牧干扰等问题.分子遗传学和形态学数据都充分证明,滇金丝猴是独立的种.生态学研究表明,滇金丝猴的食性存在季节性差异,其某种程度上的海拔迁移是食物的空间分布和温度相互作用的结果.种群遗传学研究进一步表明,滇金丝猴的遗传多样性比较贫乏,个体间的遗传距离P平均仅为 0.052.建议保护区管理部门根据实际情况尽快建立生态走廊,以促进滇金丝猴的遗传稳定性和多样性.     

中国云南塔城滇金丝猴的社会结构

在云南塔城附近的山地森林中,我们利用摄象机记录了一群滇金丝猴通过山谷和在水源地饮水的过程。我们利用这些记录分析这群滇金丝猴的种群大小、组成成员以及个体的空间分布,并利用连续通过个体之间的时间间隔来揭示社会结构。塔城滇金丝猴群由366个个体组成,是目前所知最大的滇金丝猴群体。猴群内雌性个体较多。猴群可以分为26个单位,其中有19个单雄多雌单位、5个多雄多雌单位和2个全雄单位。统计结果表明单位内个体间的时间间隔显著比单位间的短。2/3以上的亚成年雄性个体和全雄单位一起活动。猴群在地面活动时全雄单位位于猴群的外围,充当前卫和后卫。塔城猴群的生命表组成结构与吾牙普亚猴群的大致一样,同样是多层社会结构,单雄多雌和全雄单位构成猴群的主体。亚成年雄性多数与全雄单位一起活动,表明雄性可能会从其出生的单雄多雌单位中迁移出来。     

气候变化和人为干扰对中国三种金丝猴地理分布的未来影响

气候变化和人为干扰正成为物种多样性丧失的重要驱动力。本文基于MaxEnt模型,探讨气候变化和人为干扰对中国3种金丝猴（川金丝猴Rhinopithecus roxellana、滇金丝猴R.bieti和黔金丝猴R.brelichi）地理分布变迁的影响：（1）气候变化和人为干扰导致3种金丝猴在2000年和未来（2050年）的适宜栖息地面积减少,分布海拔升高,其中黔金丝猴适宜栖息地面积减少最大,川金丝猴在四川东北部、陕西西南部和湖北西北部的适宜栖息地,滇金丝猴在云南西部的适宜栖息地面积收缩;（2）人为干扰指数是导致金丝猴适宜栖息地面积减少的重要因素,最暖季度平均温度、降水量变异系数、最冷季度平均温度是分别影响川金丝猴、滇金丝猴、黔金丝猴适宜栖息地的最重要气候因子;（3）川金丝猴栖息地的西南部,滇金丝猴栖息地的中部具备高连通性,适合亚群之间的交流。基于上述结果,我们建议减少低海拔地区的人类活动,并加强在受气候变化和人类干扰影响严重的栖息地进行预见性保护,比如提前规划、扩大保护地范围,在栖息地连通性低的地区修建生态廊道。我们的结果为濒危动物的保护和生态廊道的修建提供了理论依据和技术支持。     

小相岭山系大熊猫廊道规划

廊道能有效地增加栖息地斑块间的大熊猫种群交流,降低种群灭绝的风险。小相岭山系是现存大熊猫种群数量最少的山系之一。通过MAXENT(Maximum Entropy)分析,发现小相岭山系存在7个相对隔离的栖息地斑块,栖息地破碎化严重。为了增加小相岭山系大熊猫种群交流,利用最小代价路径原理和电流理论,从保护管理角度出发,在该区域划定了9条连接大熊猫栖息地斑块的廊道。其中紫马-麻麻地廊道连接该区域面积最大、大熊猫痕迹点最多的两个栖息地斑块,生态意义重大,建议优先建设该廊道。此外,研究划定的多个廊道彼此邻近,甚至存在一定程度的重叠。将这些极其邻近或者重叠的廊道合并,并提出"廊道群"的概念。廊道群是两个或两个以上极其相邻的廊道构成的网状结构,廊道群作为景观上的网状结构,能同时连接多个栖息地斑块,更有效地增加多个栖息地斑块间的种群交流。由于农田的挤压,部分廊道难以达到大熊猫廊道的最低宽度需求(2230 m),制约了其生态效应的发挥,建议在以后的保护工作中探索农田区域的栖息地恢复方式。     

景观空间格局对滇金丝猴猴群分布的影响

结合景观生态学,建立研究区域景观格局分析与内部生物之间的联系,能够为生物多样性保护和自然保护区的管理提供更加真实准确及可实践操作的指导。借助遥感和地理信息系统软件,将滇金丝猴分布区内景观划分为适宜生境、次适宜生境、连接生境、天然阻碍及人为干扰5种类型,通过计算得到5种类型斑块的景观指数,并将其与滇金丝猴猴群出现概率及种群密度进行相关性分析。结果表明:(1)滇金丝猴猴群出现概率受人为干扰斑块影响较大,与人为干扰斑块面积所占比例呈负相关,与人为干扰斑块的权重边界密度呈正相关;(2)影响猴群分布密度的景观指数较多,其中除适宜生境斑块所占面积比及其权重边界密度与猴群密度呈正相关之外,其他指数均与猴群密度呈负相关;(3)现阶段对滇金丝猴生境保护最为直接的方法应该是增加适宜生境和次适宜生境斑块间的连通性,即增强这两类斑块的自然增扩潜力,同时减少人为干扰对猴群的影响;(4)对于自然保护的管理应当更加重视边界效应的作用,尽量保持适宜生境与其性质相近类型斑块的连通性,以提高景观质量。     

基于最小费用模型的景观连接度评价

作为物种扩散的重要影响因子,景观连接度反映了景观促进或阻碍生物体在资源斑块间运动的程度,它也是区域土地可持续利用和生物保护领域的主要指标.最小费用模型起源于图论,其结合了景观中的详细地理信息和生物体的行为特征,通过费用距离分析可直观形象地描绘出物种在异质景观中的连接度,且可在GIS程序包中实现简便运算和适度的数据需求量,使其在大尺度景观连接度评价中受到广泛关注.本文结合当前的景观连接度研究,详细阐述了最小费用模型评价景观连接度的意义、原理及运算过程,并探讨了该模型应用中存在的问题,以期为进一步开展相关研究及生物多样性保护提供依据.     

Identification of 13 Human Microsatellite Markers via Cross-species Amplification of Fecal Samples from Rhinopithecus bieti

Yunnan snub-nosed monkeys (Rhinopithecus bieti) are 1 of 3 snub-nosed monkey species endemic to China. Only ca. 1500 individuals remain in high-altitude forests 3000–4500 m above sea level on the Tibetan Plateau, making them the nonhuman primate living at the highest known elevation. It is one of the most endangered 25 primate species in the world. Proper knowledge of the population genetics and social system of Rhinopithecus bieti will contribute to more appropriate conservation management decisions. Cross-species amplification of human microsatellite loci has facilitated analysis of the population genetics and reproductive strategies of various primate species. We screened 72 human-derived markers to assess their utility in Yunnan snub-nosed monkeys. Thirteen of them produced reliable results and exhibited moderate levels of polymorphism.     

景观遗传学：概念与方法

全球变化下的物种栖息地丧失和破碎化给生物多样性保护带来了新的问题和挑战,生物多样性保护必须由单纯的物种保护上升到栖息地景观的保护。景观遗传学是定量确定栖息地景观特征对种群遗传结构影响的一门交叉学科,在生物保护及自然保护区管理方面有巨大的潜力。从生物多样性保护的角度评述了景观结构与遗传多样性的关系,介绍了景观遗传学的基本概念,研究尺度和方法,并对景观遗传学当前的研究焦点及面临的挑战做了总结。     

Improving landscape connectivity for the Yunnan snub-nosed monkey through cropland reforestation using graph theory

Habitat fragmentation is a threat to biodiversity because it restricts the ability of animals to move. Maintaining landscape connectivity could promote connections between habitat patches, which is extremely important for the preservation of gene flow and population viability. This paper aims to evaluate the landscape connectivity of forest areas as it relates to the conservation of the Yunnan snub-nosed monkey (Rhinopithecus bieti), an emblematic and endemic endangered primate species. Specifically, this study seeks to model ways to improve connectivity via cropland reforestation scenarios which incorporate graph theory and genetic distances. The connectivity improvement assessment is performed at two nested scales. At the regional scale, the aim is to quantitatively assess the gain in connectivity from different reforestation scenarios, in which croplands are replaced by different kinds of forest habitats. At the local scale, the goal is to prioritize and to locate croplands based on the gain in connectivity that they would provide if they were reforested. The results indicate that the four reforestation scenarios have different impacts on connectivity; the fourth scenario, in which reforestation is accomplished with plant species that provide optimal monkey habitat, yields the greatest increase in connectivity (+24% versus less than +2% for the others). Prioritization of the 1482 cropland patches shows that the 10 best patches increase connectivity from 0.04% to 9.1% as the isolation threshold distance increases. This kind of graph theoretic approach appears to be a useful tool for connectivity assessment and the development of conservation measures for species impacted by human activities.     

Population structure and landscape genetics in the endangered subterranean rodent Ctenomys porteousi

In order to devise adequate conservation and management strategies for endangered species, it is important to incorporate a reliable understanding of its spatial population structure, detecting the existence of demographic partitions throughout its geographical range and characterizing the distribution of its genetic diversity. Moreover, in species that occupy fragmented habitats it is essential to know how landscape characteristics may affect the genetic connectivity among populations. In this study we use eight microsatellite markers to analyze population structure and gene flow patterns in the complete geographic range of the endangered rodent Ctenomys porteousi. Also, we use landscape genetics approaches to evaluate the effects of landscape configuration on the genetic connectivity among populations. In spite of geographical proximity of the sampling sites (8–27 km between the nearest sites) and the absence of marked barriers to individual movement, strong population structure and low values of gene flow were observed. Genetic differentiation among sampling sites was consistent with a simple model of isolation by distance, where peripheral areas showed higher population differentiation than those sites located in the central area of the species’ distribution. Landscape genetics analysis suggested that habitat fragmentation at regional level has affected the distribution of genetic variation among populations. The distance of sampling sites to areas of the landscape having higher habitat connectivity was the environmental factor most strongly related to population genetic structure. In general, our results indicate strong genetic structure in C. porteousi, even at a small spatial scale, and suggest that habitat fragmentation could increase the population differentiation.     

Temporally dynamic habitat suitability predicts genetic relatedness among caribou

Landscape heterogeneity plays a central role in shaping ecological and evolutionary processes. While species utilization of the landscape is usually viewed as constant within a year, the spatial distribution of individuals is likely to vary in time in relation to particular seasonal needs. Understanding temporal variation in landscape use and genetic connectivity has direct conservation implications. Here, we modelled the daily use of the landscape by caribou in Quebec and Labrador, Canada and tested its ability to explain the genetic relatedness among individuals. We assessed habitat selection using locations of collared individuals in migratory herds and static occurrences from sedentary groups. Connectivity models based on habitat use outperformed a baseline isolation-by-distance model in explaining genetic relatedness, suggesting that variations in landscape features such as snow, vegetation productivity and land use modulate connectivity among populations. Connectivity surfaces derived from habitat use were the best predictors of genetic relatedness. The relationship between connectivity surface and genetic relatedness varied in time and peaked during the rutting period. Landscape permeability in the period of mate searching is especially important to allow gene flow among populations. Our study highlights the importance of considering temporal variations in habitat selection for optimizing connectivity across heterogeneous landscape and counter habitat fragmentation.     

The effect of landscape features on population genetic structure in Yunnan snub-nosed monkeys (Rhinopithecus bieti) implies an anthropogenic genetic discontinuity

The Tibetan Plateau is one of the top 10 biodiversity hotspots in the world and acts as a modern harbour for many rare species because of its relatively pristine state. In this article, we report a landscape genetic study on the Yunnan snub-nosed monkey ( Rhinopithecus bieti ), a primate endemic to the Tibetan Plateau. DNA was extracted from blood, tissue and fecal samples of 135 wild individuals representing 11 out of 15 extant monkey groups. Ten microsatellite loci were used to characterize patterns of genetic diversity. The most striking feature of the population structure is the presence of five subpopulations with distinct genetic backgrounds and unique spatial regions. The population structure of R. bieti appears to be shaped by anthropogenic landscape features as gene flow between subpopulations is strongly impeded by arable land, highways and human habitation. A partial Mantel test showed that 36.23% ( r  =   0.51, P  =   0.01) of the genetic distance was explained by habitat gaps after controlling for the effect of geographical distance. Only 4.92% of the genetic distance was explained by geographical distance in the partial Mantel test, and no significant correlation was found. Estimation of population structure history indicates that environmental change during the last glacial maximum and human impacts since the Holocene, or a combination of both, have shaped the observed population structure of R. bieti . Increasing human activity on the Plateau, especially that resulting in habitat fragmentation, is becoming an important factor in shaping the genetic structure and evolutionary potential of species inhabiting this key ecosystem.     

卧龙自然保护区大熊猫生境破碎化研究

生境破碎化主要有两个方面,一是形态（景观结构）上的破碎化;二是生态功能上的破碎化,将景观连接度的概念引入卧龙自然保护区大熊猫的生境评价研究中,通过选择影响大熊猫生存的３种典型景观因子;地形高度,地形坡度和食物来源,从生态功能上研究３种景观因子由于空间组合的不匹配而形成的生境破碎化现状,在生物各景观因子重要性的基础上进行景观连接模糊相对赋值,并建立景观连接度评价模型,在地理信息系统支持下,研究了卧龙     

Fission–Fusion Behavior in Yunnan Snub-Nosed Monkeys (Rhinopithecus bieti) in Yunnan, China

Several species of mammals live in relatively large social groups that temporarily fission or subgroup in response to changes in food availability, predation risk, foraging strategies, and mating competition. Although the dynamics of subgrouping are not well understood, evidence of facultative fission–fusion behavior in species that generally exhibit a highly cohesive group structure may help to clarify the set of ecological and social factors that constrain or affect group size in primates. We here examined patterns of subgrouping in Yunnan snub-nosed monkeys (Rhinopithecus bieti) inhabiting the Baimaxueshan National Nature Reserve in Yunnan, China. Rhinopithecus bieti lives in a large multilevel society consisting of 6–41 one-male, multifemale units (OMUs) and one all-male unit (AMU). Over a 5-yr period from 2003 through 2008, we tracked a group of >450 Rhinopithecus bieti. We recorded the location in the group’s home range where fission and fusion events occurred, the size and number of subgroups, days spent in subgroups, and food availability, and monitored predator sightings. The results indicate that the focal group underwent12 group fission events, all of which occurred between mid-June and July, and all in the same area of the group’s range. During these fissioning events, the AMU also showed subgrouping behavior. In all cases, the presence of bamboo shoots, an important seasonal component of the snub-nosed monkey diet, appeared to trigger subgrouping behavior. The subgroups reunited in other parts of their range after a period of 2–11?d. We found no evidence that the presence of predators had a direct affect on subgrouping behavior in Rhinopithecus bieti, as proposed in previous studies.