大兴安岭北部地区原始林火干扰历史的研究

在大兴安岭阿龙山林业局的一个集水区,通过样地法（９６个样地）,调查了大量的火疤木,研究了景观水平上的火状况。结果表明,由１８２５至１９９３年间样区共发生１４次火灾,火烧种类主要是地表火,但也有少量树冠火;火烧强度主要为弱度火;火场面积通常很大;火烧平均间隔期为３７ａ,火烧轮回期的约３０ａ。这些指标对大于大兴安岭北部林区有一定的代表意义。大兴安岭北部林区的火状况主要决定于兴安落叶松的抗火特性和森林群     

次生林概念与生态干扰度

近一个世纪强烈的人为干扰使世界范围内的原始林面积锐减,次生林已成为中国乃至世界森林资源的主体.虽然在文献与现实中"次生林（Secondary forest）"被广泛使用,但次生林的概念在各个国家,甚至同一国家或地区以及各种不同文献中存在相互矛盾的情况,这给次生林研究与经营实践带来诸多不便;而不准确的次生林定义也为与各个层次的决策制定者及公众之间的交流带来了障碍.本文在查阅大量国内外关于次生林概念文献的基础上,结合近年来关于次生林生态与经营研究实践,综合分析了次生林概念的不确定性,同意以往次生林定义中的基本内涵,并认为：次生林是由于人为破坏性干扰或异常自然干扰使原始林固有的林分结构、物种组成或基本功能发生了显著变化,经过天然更新或人工诱导天然更新恢复形成的林分.但该定义中仍存在着很多不确定性, 如:怎样的干扰为"人为破坏性干扰"和"异常自然干扰";"林分结构、物种组成或基本功能"发生了怎样的变化为"显著变化";"人工诱导天然更新"中"人工"参与的成分比例如何等.次生林概念是在20世纪初由植物演替学家提出,当时未考虑干扰的持续性;而实际上,无论是次生林还是原始林,均是森林生态系统演替过程中的某一状态,在现代森林生态系统研究中,应重新规范"次生林"的概念.考虑到"次生林"定义的不确定性或困难性,建议使用"森林自然度"或"森林生态系统成熟度"或"森林干扰度"来表达现实森林所处的状态,但该方面的研究与实践尚需加强.     

高原鼠兔扰动对高寒草地植物群落特征的影响

高原鼠兔是青海湖流域高寒草地主要的啮齿动物.本文基于R-Vegan中的RDA排序方法,以有效洞口数差异将高原鼠兔扰动强度划分为4组,分析不同扰动强度下高寒草地植物群落特征,进而提出群落演替的概念模型,探究高原鼠兔扰动对高寒草地生态系统及放牧质量的影响.结果表明:随着扰动强度加大,出现以灯芯草为优势种的群落向以草地早熟禾、海乳草为优势种的群落演替.当扰动强度较小时,群落的总盖度、地上生物量、物种多样性和物种丰富度较高,但杂类草植物比例较高;当扰动强度较大时,各群落特征值较低且杂类草植物比例最高;当扰动强度适中时,各群落特征值比较高,禾本科和莎草科植物比例最大.因此,轻度扰动时,虽然群落特征值高但放牧质量低;过度扰动时出现草场植被退化;而扰动强度在阈值内可维持高寒草地生态系统稳定并提高放牧质量.     

Teasing History,Onset of Obesity,Current Eating Disorder Psychopathology,Body Dissatisfaction,and Psychological Functioning in Binge Eating Disorder

Objective: The primary goal of this study was to examine associations among teasing history, onset of obesity, current eating disorder psychopathology, body dissatisfaction, and psychological functioning in women with Binge Eating Disorder (BED). Research Methods and Procedures: Subjects were 115 female adults who met DSM‐IV criteria for BED. Measurements assessing teasing history (general appearance [GAT] and weight and size [WST] teasing), current eating disorder psychopathology (binge frequency, eating restraint, and concerns regarding eating, shape, and weight), body dissatisfaction, and psychological functioning (depression and self‐esteem) were obtained. Results: History of GAT, but not WST, was associated with current weight concerns and body dissatisfaction, whereas both GAT and WST were significantly associated with current psychological functioning. Patients with earlier onset of obesity reported more WST than patients with later onset of obesity, but the groups did not differ significantly in GAT, current eating disorder psychopathology, body dissatisfaction, or psychological functioning. Obese women reported more WST than non‐obese women, but no differences in GAT or the other outcome variables were observed. Higher frequency of GAT was associated with greater binge frequency in obese women, and with greater eating restraint in non‐obese women. Discussion: Although physical appearance teasing history is not associated with variability in most eating disorder psychopathology, it is associated with related functioning, most notably body dissatisfaction, depression, and self‐esteem. Our findings also suggest that the age of onset of obesity and current body mass index status in isolation are not associated with eating psychopathology or associated psychological functioning in adult patients with BED.     

Factors Influencing Succession: Lessons from Large, Infrequent Natural Disturbances

Disturbance events vary in intensity, size, and frequency, but few opportunities exist to study those that are extreme on more than one of these gradients. This article characterizes successional processes that occur following infrequent disturbance events that are exceptional in their great intensity or large size. The spatial variability in disturbance intensity within large, infrequent disturbances (LIDs) often leads to a heterogeneous pattern of surviving organisms. These surviving organisms dictate much of the initial successional pattern on large disturbances where the opportunities for seeds to disperse into the middle of the disturbance are limited. The traditional distinction between primary and secondary succession is insufficient to capture the tremendous variability in succession following LIDs. Disturbance size influences succession where long-distance colonization by propagules is important. Observations from LIDs suggest the following interrelated hypotheses about trends in succession with increasing distance from seed sources when disturbanceintensity is high: (a) initial densities of organisms will be lower; (b) nucleation processes, in which recovering patches serve as foci for additional colonization and expand spatially, will be more important; (c) competitive sorting will be less important relative to chance arrival in determination of community composition, and (d) community composition will be initially less predictable; and (e) the rate of recovery of community composition will be slower. Prediction of succession following LIDs without considering contingencies such as the abundance, types, and spatial distribution of residuals, and distance to seed sources is likely to be unsuccessful for large portions of the landscape. Abundance and spatial arrangement of survivors and arrival patterns of propagules may be the pivotal factors determining how succession differs between intense disturbances of large and small extent. Received 14 July 1998; accepted 18 September 1998     

Factors related to diversity of decomposer fungi in tropical forests

Recent studies suggest that host-preferences are common among certain groups of tropical fungal decomposers but rare in others, and sometimes occur where we least expect them. Host preferences among microfungi and ascomycetes that decompose leaf litter are common but usually involve differences in relative frequencies more than presence/absence, so their diversity may be loosely correlated with species richness of host trees. Strong host-specificity appears to be rare among wood decomposer fungi, whereas characteristics of their substrata and habitat are very important for this group. Anthropogenic disturbance predisposed a tropical forest to subsequent hurricane damage, and the resulting direct and indirect effects on host diversity and habitat heterogeneity were reflected in the decomposer fungal community more than sixty years after the original disturbance. While species richness of dictyostelid slime molds and functional diversity of their bacterial prey increased with disturbance, the more diverse microfungi and ascomycetes were apparently negatively affected by disturbance.     

Effect of wave exposure on vegetation abundance, richness and depth distribution of shallow water plants in a New Zealand lake

SUMMARY 1. The effects of physical disturbance in terms of wave exposure, shore slope and substrate mobility on the presence, species richness, cover and depth limits of the low‐growing, shallow water macrophyte community (called the low mixed community) were examined at 41 shore sites in Lake Wanaka, South Island, New Zealand. 2. Wave exposure at a site was described by the previous year's maximum depth of sediment motion and maximum vertical extension of waves, determined from a computer wave model. Shore slope at each site was recorded from ?1 to 0 m depth, and sediment stability was assessed as the cover of small gravel. 3. The low mixed community was only present on sites where the previous year's maximum depth of sediment motion was <8 m, maximum wave run‐up was <0.3 m, shore slope <0.12 m m^?1, and small gravel cover <78%. 4. Species richness, cover and depth limits of the low mixed community decreased with increasing disturbance on the sites. Sixty‐two percentage of the variation in species richness could be explained by physical disturbance variables when all sites were included (N=41). When only sites with a low mixed community were included (N=22), only 18% of the variation was explained. Species richness within sites supporting a low mixed community is thus poorly explained by physical disturbance, whereas presence or absence is better explained. There was no evidence to support the intermediate disturbance hypothesis in this study. 5. Disturbance as a result of waves explained 86% of the variation in cover among sites with a low mixed community and accounted for 68 and 58% of the variation in upper and lower depth limit of the low mixed community, respectively. 6. The models obtained in this study can be used as predictive models for the low mixed community in New Zealand lakes in relation to natural physical disturbance on the shore. By integrating these results with previous studies on the effect of water level fluctuation, we describe a generalised optimum physical habitat for the low mixed community in New Zealand lakes.     

基于有害干扰的森林生态系统健康评价指标体系的构建

在分析国内外提出的众多森林生态系统健康评价指标的不足后,对评价指标进行研究和筛选。最终在森林生态系统健康评价指标体系的构建上提出了一个新的思路,即从森林火灾、林业有害生物、大气污染、人为有害干扰以及森林生态系统内部的增益干扰5个方面选取20个指标构建森林生态系统健康评价指标体系。其中森林火灾干扰包括平均降水量、平均气温、郁闭度、海拔、坡度、坡向、易燃树种的比例和林道距离8个指标,林业有害生物包括有害生物等级、危害程度和寄主树的比例3个指标,大气污染干扰通过叶片、土壤和污染物的分析测定,人为有害干扰包括森林经营措施、采伐措施和林下植被管理3个方面,而森林生态系统内部的增益干扰由物种多样性、群落结构和近自然度3个指标构成。同时对关键评价指标的意义进行了具体分析。此指标体系摒弃传统的评价观念,结合了近年来影响全国森林健康的几个重要原因,更能准确的反应目前森林生态系统的健康状况。研究思路和方法的提出在一定程度上可以丰富森林生态系统健康评价研究理论与方法体系。     

Limited effects of fire disturbances on the species diversity and structure of ant-plant interaction networks in Brazilian Cerrado

Fire is one of the main natural disturbances in Tropical Savannas, changing the diversity of species, altering the structure of species interactions, and driving the evolution of adaptations. Here, we investigated the effects of fire disturbance on interactions between ants and plants with extrafloral nectaries in Cerrado (Brazilian Savanna). We carried out the study in two different ecosystems of Brazilian Cerrado 700 km apart; Woody Cerrado and Rupestrian Grasslands. We conducted a Before-After-Control-Impact (BACI) experiment, in which the impact was the disturbance caused by fire. In Woody Cerrado, we found no evidence of fire affecting the diversity and composition of plants or its interactions. Fire also did not affect ant diversity but changed the interaction pattern of its interactions by reorganizing the paired interactions between species (i.e., rewiring). However, this effect did not result in changes on the overall structure of the network. In Rupestrian Grasslands, fire also did not affect the diversity and composition of plant species or its interactions, but it did increase the number of ant species and change its composition, leading to a reorganization of the its paired interactions. However, these fire disturbances in the ant level did not affect the overall structure of the network. Our findings indicate that the structure of ant-plant interaction networks is robust to fire disturbances, more in Woody Cerrado than Rupestrian Grasslands, confirming our hypothesis that ant-plant interactions in Cerrado are adapted to fire disturbances. In sum, our study enhances the understanding of the effects of environmental disturbances and the stability of the ant-plant interactions in fire-adapted ecosystems such as Brazilian Cerrado.     

Vegetation patterns and their dependency on site conditions in the pre-industrial landscape of north-eastern Japan

We reconstructed the vegetational landscape of the pre-industrial era (the beginning of the twentieth century) in north-eastern Japan, and estimated the distribution patterns of traditional land-uses, as suggested from the vegetation. We found significant correspondence between the spatial patterns of vegetational landscape and site attributes, and hypothesized the underlying mechanisms. The study area was classified into three vegetation types: grasslands, secondary forests and old-growth forests. It was determined that the grasslands were formed and maintained by burning; secondary forests were derived from either charcoal woods or forests recovered on abandoned grasslands; and old-growth forests had suffered the least anthropogenic disturbance. Each past vegetation type showed significant dependency on site attributes such as altitude, slope angle, slope aspect, hydrological topography and distance from the nearest human habitation. The relative importance of these site attributes varied depending on the vegetation type. Grasslands and old-growth forests, which were the most and the least disturbed sites in the study area, respectively, showed clear contrasts in their dependencies especially on the slope aspect and on elevation. These site attributes were thought to have had influences on each vegetation type by determining the inflammability of the site. Satellite photographs indicated that north-facing valleys had been relatively wet throughout the fire-prone spring season. Hence, these areas would have been free from frequent fire, and more likely to preserve old-growth forests. Ground wetness in spring was thought to be the underlying factor determining the contrasts in past vegetation and land-use patterns in the area.An erratum to this article can be found at     

草地群落放牧干扰梯度β多样性研究

放牧过程通过牲畜的啃食、践踏作用干扰草场环境,使草地群落的物种组成发生变化,植物种群的优势地位发生更替。结果表明,随放牧干扰强度加重,从盐湿化草甸到典型草原,群落植物种丰富度呈下降趋势。β多样性测度结果显示,盐湿化草甸和羊草杂类草草甸群落物种变化的中度干扰出现在轻牧→中牧阶段,并在整个放牧干扰进程中,表现较低的稳定性;草甸草原和典型草原群落出现在中牧→重牧阶段;而荒漠草原物种变化表现出高度的稳定性,从轻牧到过牧物种替代仅1～3种。各群落放牧干扰植物多样性的稳定性次序是:荒漠草原>典型草原≥草甸草原>盐湿化草甸.     

Reciprocal relationships and potential feedbacks between biodiversity and disturbance

Two major foci of ecological research involve reciprocal views of the relationship between biodiversity and disturbance: disturbance determines community diversity or diversity determines realized disturbance severity. Here, we present an initial attempt to synthesize these two approaches in order to understand whether feedbacks occur, and what their effects on patterns of diversity might be. Our review of published experiments shows that (i) disturbance severity can be both a cause and a consequence of local diversity in a wide range of ecosystems and (ii) shapes of the unidirectional relationships between diversity and disturbance can be quite variable. To explore how feedbacks between diversity and disturbance might operate to alter expected patterns of diversity in nature, we develop and then evaluate a conceptual model that decomposes the relationships into component parts, considering sequentially the effect of diversity on disturbance severity, and the effect of realized disturbance on diversity loss, subsequent recruitment, and competitive exclusion. Our model suggests that feedbacks can increase mean values of richness, decrease variability, and alter the patterns of correlation between diversity and disturbance in nature. We close by offering ideas for future research to help fill gaps in our understanding of reciprocal relationships among ecological variables like diversity and disturbance.     

Response of ant and terrestrial spider assemblages to pastoral and military land use,and to landscape position,in a tropical savanna woodland in northern Australia

This study aims primarily to assess the response of two invertebrate groups to the effects of pastoralism and military training, at one site in the tropical savanna of north‐eastern Queensland. The richness and species composition of ants and terrestrial spiders were examined at two contrasting times of year across three land use treatments (pastoralism, military training and undisturbed) and four landscape positions (upper slope to riparian). Ant species richness was least in the grazed sites, and a high proportion of the ant species recorded varied significantly in frequency between the grazed and the two ungrazed land uses. This variation was generally greater than that associated with landscape position. Although variation in the richness of spiders was significantly related to land‐use type, this effect was less pronounced than for ants, was less marked than variation associated with landscape position and was confounded by a strong interaction between land use and landscape position. Quadrat‐scale variation in the composition of spider assemblages was influenced most by season of sampling. For both spiders and ants, there were few differences in richness or species composition between undisturbed land and that managed for military use.     

社会-生态系统视角下沙漠化逆转定量评价——以宁夏盐池县为例

对沙漠化逆转区进行有效管理是沙漠化治理至关重要的环节,研究沙漠化逆转区社会-生态系统的干扰状况可以为沙漠化逆转区的管理提供理论支持。基于MODIS NDVI产品数据,用移动窗口法则计算了不同空间尺度上盐池县社会-生态系统的干扰强度和干扰连通度,并分析了2000—2015年间不同时间段内宁夏盐池县社会-生态系统干扰的空间分布。结果表明:(1)盐池县不同时间段内社会-生态系统干扰的空间分布具有较大差异,2000—2004年强干扰主要集中于盐池县的南部;2004—2008年强干扰在北部、中部均有表现;2008—2012年强干扰分别位于东、中、西3个小区域,并没有集中于一个区域,且北部强干扰区域进一步增强;2012—2015年强干扰的区域主要集中于县域的北部、中西部和西北部。(2)不同空间尺度上社会-生态系统干扰强度和连通度有很大差异,随着移动窗口的增大,不同集群的干扰类型也发生了变化,主要表现为低干扰离散型向低干扰集聚型转变,高干扰集聚型向低干扰离散型转变。(3)总体上看,除了个别区域社会-生态系统干扰强度和连通度较大以外,盐池县大部分地区社会-生态系统受干扰的强度和连通度并不大,沙漠化逆转程度较低,还有待进一步加强沙漠化治理力度。     

亚高山云冷杉混交林树木生长释放与干扰分析

对云南碧塔海亚高山云冷杉林内４个样地冠层树木的生长压制和释放的历史,用树木年轮分析方法进行了重建,然后根据生长释放频率推测林冠干扰强度（每１０年冠层树木的死亡百分率）。４个林分（１个中龄林,３个成过熟林）生长释放的平均百分率为４８％～９２％。中龄林内,平均生长释放频率为７１％／１０ａ,成过熟林则为７４％～９５％／１０ａ,在油麦吊云杉〔Ｐｉｃｅａｂｒａｃｈｙｔｙｌａｖａｒ．ｃｏｍｐｌａｎａｔａ（Ｍａｓｔ．）ＣｈｅｎｇｅｘＲｅｈｄ．〕占优势的林分和大果红杉（Ｌａｒｉｘｐｏｔａｎｉｎｉｖａｒ．ｍａｃｒｏｃａｒｐａＬａｗ）油麦吊云杉混交林分内,估测的林冠干扰强度分别为４８％／１０ａ和５９％／１０ａ。     

The effects of investigator disturbance on procellariiform seabirds: A review

Abstract

Despite long‐held concerns about the effects of researchers on breeding birds, few studies have focused on the impact of investigators on Procellariiformes. In this review, we summarise published investigations concerning the effects of investigators on physiology, behaviour, reproductive success, offspring quality, and population trends of procellariiform seabirds. Many of the smaller procel‐lariid taxa, such as storm‐petrels (Hydrobatidae, and some shearwater Puffinus species) are particularly sensitive to handling during the incubation period, resulting in lowered reproductive success, burrow shifts, and increased divorce between pairs. However, repeated handling of chicks does not seem to have a discernible effect on chick quality. In larger procellariiforms, the presence of researchers within the breeding colony is associated with significant increases in heart rates. Therefore, researchers seeking unbiased estimates of demographic and ecological parameters of birds should be encouraged to measure their own impact and report the findings in the literature, even if they detect no adverse effects of investigator disturbance. Techniques should be developed that ensure the accurate recording of birds’ natural behaviour while minimising the impact of investigator disturbance. If investigators are willing to study disturbance problem s, it should be possible to reduce biases caused by their activities.     

Moving from pattern to process: coexistence mechanisms under intermediate disturbance regimes

Coexistence mechanisms that require environmental variation to operate contribute importantly to the maintenance of biodiversity. One famous hypothesis of diversity maintenance under disturbance is the intermediate disturbance hypothesis (IDH). The IDH proposes patterns of peaked diversity under intermediate disturbance regimes, based on a tension between competitively superior species and species which can rapidly colonize following disturbance. We review the literature, and describe recent research that suggests that more than one underlying mechanism can generate this unimodal diversity pattern in disturbed environments. Several exciting emerging research areas are identified, including interactions between disturbance types, operation of the IDH in multi‐trophic systems, and changes in disturbance regimes. However, empirical work is still focussed on describing the IDH pattern, with little emphasis on identifying its mechanistic basis. We discuss how to extend methods for identifying different coexistence mechanisms, developed in the theoretical literature, to experimental research. In an attempt to operationalize these various ideas we outline a hypothetical IDH research programme. A solid understanding of the life history attributes of the component species and their responses to disturbance will facilitate identification of the coexistence mechanism(s) underlying the IDH pattern, and provide a framework by which empirical and theoretical results can be more fully integrated.     

干扰对动物传播森林植物种子有效性影响的研究进展

干扰在森林生态系统中普遍存在,并影响森林的更新和演替.动物传播种子是种子更新的必经阶段,其对森林干扰的响应在一定程度上能够预测未来的森林群落组成和结构变化,对于明确森林演替方向具有重要意义.本文论述了森林干扰对动物传播种子有效性(包括动物传播种子的数量和质量)影响研究的生态学意义,全面揭示了自然干扰(火干扰、林窗干扰等)和人为干扰(生境破碎化、狩猎、采伐等)对动物传播种子数量、传播距离以及传播后幼苗更新影响的研究进展,指出干扰通过影响动物种群动态,进而造成动物传播种子数量发生了改变,动物传播种子的距离对干扰的响应基本表现出轻微负相关;干扰对传播后幼苗更新的影响结果因干扰类型的不同而复杂多变,干扰迹地环境因子的变化也影响着传播后的种子萌发和幼苗更新.干扰对动物传播种子有效性影响研究中存在的问题,主要表现为火干扰迹地恢复过程、增益性的干扰(如抚育、间伐、林窗)等对种子传播有效性影响研究的匮乏,以及忽略了温带森林内的干扰对动物传播种子的影响等.今后,应开展干扰对种子传播有效性的长期研究;对于干扰多发地带的森林,应高度重视增益性干扰影响动物传播植物种子的研究.