地质统计学理论与方法及其在昆虫生态学中的应用

空间相关是昆虫生态学中普遍存在的一种客观现象 ,但这种空间相关性在传统的统计学分析中被忽略了。据此 ,文章对常用的地质统计学的空间相关理论和方法、以及这些理论和方法在昆虫生态学中的应用途径和研究进展作了简述。此外 ,对GIS在昆虫空间相关分析中的应用途径和方法也作了探讨。通过综合分析和比较 ,作者认为 ,未来地质统计学的发展将更多地与GIS融为一体 ,并且二者将与传统的时间序列方法和生物统计学方法有机结合 ,共同应用于昆虫生态学的时空分析和预测之中     

土壤微生物群落构建理论与时空演变特征

土壤微生物作为陆地生态系统的重要组成部分,直接或间接地参与几乎所有的土壤生态过程,在物质循环、能量转换以及污染物降解等过程中都发挥着重要作用。对土壤微生物时空演变规律及其形成机制的研究,不仅是微生物演变和进化的基础科学问题,也是预测微生物及其所介导的生态功能对环境条件变化响应、适应和反馈的理论依据。讨论了土壤微生物群落的定义、测度方法和指标,认为群落是联系动植物宏观生态学与微生物生态学的基础,群落构建机制是宏观和微观生态学都需要研究的核心科学问题;从生态学的群落构建理论出发,阐述了包括生态位理论/中性理论、过程理论和多样性-稳定性理论在土壤微生物时空演变研究中的应用,以及微生物群落在时间和空间上的分布特征及其尺度效应;确立了以微生物群落构建理论为基础、不同时空尺度下土壤微生物群落演变特征为主要内容的微生物演变研究的基本框架。     

昆虫生态学试验设计中时空转换的技巧

时空转换最初是研究植物群落演替的方法,目前作为一种理论推断在社会科学、地理信息和地质分析等领域应用,在昆虫生态学中的应用很少,本文介绍了空间换取时间与时间换取空间两种方法,能够巧妙地缩短很多昆虫生态学的试验时间,或增加研究范围内的样本数,在大尺度景观研究昆虫迁移、预测预报、栖境恢复等方面具有重要意义。这种时空转换的技巧在昆虫生态学的研究的有广阔的应用前景。     

对生态学问题的实验探讨

一、引言所有科学的起始都必然是在于事实和现象的描述与分类。在生态学中,许多观察和描述还有待进行,但是我们也需要更多地了解植物与它们的环境的相互关系。我们有几条路去探索这些关系。为了达到一个有预先性的生态学,生态学者们惯于用相关的方法。不幸,植物和它的环境都是几乎无限地复杂,因而它们的相互关系也是同样地繁杂而难于阐明。这正是生理学家跨进来的地方。尽管在一个多坐标的单元(植物)与一个不断变化的环境因素综合体在相互作用的复杂情况下,他的实验方法使他能建立因果的关系。     

生态学中的尺度及尺度转换方法

尺度作为生态学的重要范式,已经引起了广泛重视,但对尺度问题的研究还不够成熟.尺度具有多维性特点,即功能尺度、空间尺度、时间尺度等,但生态学研究的重点是空间和时间尺度.并且时空尺度还具有复杂性、变异性特征.尺度研究的根本目的在于通过适宜的空间和时间尺度来揭示和把握复杂的生态学规律.为此,科学有效的尺度选择和尺度转换方法不可或缺.常见的尺度转换方法有图示法、回归分析、变异函数、自相关分析、谱分析、分形和小波变换,同时遥感和地理信息系统技术在尺度研究中也发挥着重要作用.结合实例对上述方法进行了分析和论述,认为各种方法都有其内在的优势和不足,新方法的引入和应用对于尺度转换方法体系的充实和完善非常重要.有关尺度的研究将进一步加强,研究的重点是尺度变异性、不同尺度间的相互作用机制以及尺度转换方法等.     

生态学中的尺度及尺度转移方法

尺度作籽生态学的重要范式,已经引起了广泛重视,但对尺度问题的研究还不够成熟。尺度具有多样性特点,即功能尺度,空间尺度、时间尺度等,但生态学研究的重点是空间和时间尺度。并且时空尺度还具有复杂性、变异性特征、尺度研究的根本目的在于通过适宜的空间和时间尺度来揭示和把握复杂的生态学规律。为此,科学有效的尺度选择和尺度转换方法不可或缺。常见的尺度转换方法有图示法、回归分析、变异函数、自相关分析、谱分析、分形和小波变换,同时遥感和地理依信息系统技术在尺度研究中也发挥着重要作用。结合实例对上述方法进行了分析和论述,认为各种方法都有有其内在的优势和不足,新方法的引入和应用对于尺度转换方法体系的充实和完善非常重要。有关尺度的研究将进一步加强,研究的重点是尺度变异性、不同尺度间的相互作用机制以及尺度转换方法等。     

从系统到景观:区域物质流分析的景观取向

物质流过程是考察系统属性的重要维度。区域物质流分析在研究框架、指标体系、数据集成、管理应用等方面的发展困境,都不同程度地反映了"黑箱假设"以及"系统隐喻"等产业生态学理论的应用局限性。基于整合复杂性科学、广义进化论的生态学组织层次理论,对区域物质流分析开展理论探讨,指出应在原有的"系统"思维之外引入"景观"概念,以拓展区域物质流分析的空间与认知维度。基于"从系统到景观"的理念,将景观生态学原理引入区域物质流分析,建构区域物质流分析的景观取向,并从空间结构与认知图式两个方面对这一取向的核心涵义做以解读。结合区域物质流分析的最新研究案例,从多尺度MFA的综合研究框架、物质流动过程的时空集成研究、物质流动过程的空间行为管理等几个方面,对区域物质流分析的景观取向做了进一步探讨。     

草地灌丛化研究进展

在草地生态系统中, 灌木入侵不仅会改变草本植物的分布格局, 还对生态系统的结构和功能产生重要影响。灌丛化的成因、影响、时空动态一直是植被生态学研究的热点问题, 这些问题的探究将有助于理解灌木在天然草原中的作用和地位, 对干旱半干旱区植被的保护和恢复具有重要科学意义。综述了灌丛化的成因、入侵后对生态系统中植被与土壤的影响、草地灌丛化空间动态变化和草地灌丛化演替过程, 以期为将来草地灌丛化的研究提供一些有益途径。     

景观生态学：生态系统的空间异质性

许多生态现象对空间异质性与空间镶嵌体内的流很敏感,作为一门涉及空间动态变化（含有机体流、物质流和能量流）和受控于异质性镶嵌体内生态流方式的学科,景观生态学提供了探索空间异质性和揭示空间格局怎样控制生态过程的新途径。景观生态学是一门研究空间格局对生态过程相互作用的科学,它促进了空间关系模型和理论的发展、空间格局与动态方面新型数据的采集以及生态学中很少强调的对空间尺度的检验。从生态学发展史来看,为方便或简化起见,空间被假定为同质的,研究过程中的尺度也被强调为均质的,这样异质性就成为一种不受欢迎的复杂…     

基于不同零模型的点格局分析

在种群空间格局研究中,定量分析格局及其形成过程已成为生态学家的主要目标。在量化分析的众多方法中,点格局分析是最常用的方法,而在选择零模型时,完全空间随机模型以外的复杂零模型很少使用,实际上,这些零模型可能有助于认识格局的内在特征。为此,我们在研究实例中,选择完全空间随机模型(complete spatial randomness)、泊松聚块模型(Poisson cluster process)和嵌套双聚块模型(nested double-cluster process)对典型草原处于不同恢复演替阶段的羊草(Leymus chinensis)种群空间格局进行了分析。结果发现:完全空间随机模型仅能检测种群在不同尺度下的格局类型;而通过泊松聚块模型和嵌套双聚块模型检验表明,在恢复演替的初期阶段,羊草种群在小尺度范围内偏离泊松聚块模型,而在整个取样范围内完全符合嵌套双聚块模型;随着恢复演替时间的推移,在恢复演替的后期,在整个取样尺度上,羊草种群与泊松聚块模型相吻合。这是很有意义的生态学现象。这一实例表明在应用点格局分析种群空间格局时,仅通过完全空间随机模型的检验来分析格局特征,或许很难论证复杂的生态过程,而选择一些完全空间随机模型以外的较复杂的零模型,可能发现一些有价值的生态学现象,对揭示格局掩盖下的内在机制有所裨益。     

Forest structure and biomass in post-agricultural forests: Lessons learned with new spatial tools

Questions: With calls for afforestation to sequester carbon due to climate change, agricultural land will be converted to forests in the near future. Little is known about how the ecosystem services of reforested landscapes with an agricultural land-use history will differ from reference forests. Our objectives were to (i) test the hypothesis that forests with a history of agricultural land use can provide the same carbon storage and biomass ecosystem services as adjacent reference forests, given some recovery time; (ii) explore whether there is a lag in the recovery of forest community composition due to prior agricultural land use; and (iii) demonstrate how remote-sensing methods can improve our understanding of land-use legacies at large spatial scales. Location: Finger Lakes National Forest, NY, USA. Methods: Using historic air photos, landscape-scale lidar, and field surveys, we compared differences in biomass storage, forest structure, and vegetation communities between reference forests and post-agricultural forests at different stages of regeneration in the Finger Lakes National Forest, New York, USA. We also used lidar to create a spatial model of biomass across the landscape to analyze the spatial distribution of biomass across our study area. Results: We found biomass and forest structure in post-agricultural forests generally recovered to levels typical of reference forests within 50 years of abandonment. Conversely, we found the composition of woody and herbaceous communities still varied between reference and post-agricultural forests after 50 years of abandonment. Conclusions: Collectively our results indicate afforestation efforts can be effective for carbon sequestration at early stages of forest succession. Our spatial model of biomass indicated that biomass levels can be low in forests with extensive edge. Further research is needed to understand how contemporary landscape structure interacts with legacy effects of agriculture to affect biomass and other ecosystem services.     

Herbaceous invaders in temperate forests: a systematic review of their ecology and proposed mechanisms of invasion

We present a systematic literature review of exotic understory forest herbaceous invasions with a focus on the forests of East Asia (EAS) and Eastern North America (ENA), two dominant regions of the north temperate deciduous forest biome. We examined the biogeographic origins of herbaceous invaders in EAS and ENA forests, summarized their life histories and ecology, and compiled the relevant literature on the 10 leading mechanistic hypotheses proposed for these invasions. We asked whether invasions of EAS and ENA forests by herbs are shared between regions, and whether a common suite of ecological traits unite these invaders into a functionally distinct group. In a focused summary of the empirical literature, we investigated if leading hypothesized mechanisms for biological invasions at large are also invoked and supported for this ecologically important, but relatively understudied, group of species. In contrast to ENA, forest invaders in EAS are overwhelmingly herbaceous (78% of forest invasions vs. 34% for ENA) and originate from different regions. Plant families represented and species traits between regions differed. Within a single species, multiple invasion mechanisms were often supported, highlighting the need for future research that simultaneously investigates multiple mechanistic hypotheses. Further, because results for a single invader often differed across space and time, a shift in focus to incorporate the complex dynamics across temporal and spatial scales with the consideration of spatial heterogeneity and the interplays among natural and anthropogenic factors to study exotic invasions is needed.     

森林碳计量方法研究进展

森林是陆地生态系统的主体,不仅是巨大的碳库而且对减缓气候变暖具有积极作用。科学有效的森林碳计量方法,有助于加深对全球碳循环过程的理解。然而,由于森林生态系统结构复杂,对森林碳计量的估算结果普遍存在精度低、不确定性高的问题。近年来,国内外发展了大量对森林碳计量进行估算的方法,主要有基于样地清查的森林植被和土壤碳估算、基于生长收获的经验模型估算、基于定量遥感雷达观测的遥感估测、基于多尺度森林生态系统网络的通量观测和陆地生态系统过程模型模拟等方法。在实际的森林碳计量中,根据不同的森林类型特征和数据获取情况,往往采取不同的碳计量方法,甚至不止一种。以生态过程模型模拟、遥感反演和数据同化技术为主要手段,基于碳通量观测数据、控制实验数据和遥感影像数据,发展多学科、多过程、多尺度的综合联网观测,充分认识森林碳循环过程中碳源/汇的时空分布特征,开展区域、洲际乃至全球尺度碳循环及其对全球变化和人类活动响应的系统性、集成性研究,以便建立高效、可靠的碳计量体系是未来林业碳计量的发展趋势。随着世界各国温室气体排放清单的编制,中国迫切需要科学的方法体系计量森林碳源/汇,提升我国在生态环境问题上的国际发言权和主导权,同时对我国森林可持续经营、生态环境保护以及美丽中国建设提供建议与支持。分析了各类森林碳计量方法的主要特征、优缺点,同时探讨了目前的森林碳计量方法存在的问题和未来的发展趋势,为不同时空尺度下森林碳计量提供参考。     

Landscape host abundance and configuration regulate periodic outbreak behavior in spruce budworm Choristoneura fumiferana

Landscape‐level forest management has long been hypothesized to affect forest insect outbreak dynamics, but empirical evidence remains elusive. We hypothesized that the combination of increased hardwood relative to host tree species, prevalence of younger forests, and fragmentation of those forests due to forest harvesting legacies would reduce outbreak intensity, increase outbreak frequency, and decrease spatial synchrony in spruce budworm Choristoneura fumiferana outbreaks. We investigated these hypotheses using tree ring samples collected across 51 sites pooled into 16 subareas distributed across a large ecoregion spanning the international border between Ontario (Canada), and Minnesota (USA). This ecoregion contains contrasting land management zones with clear differences in forest landscape structure (i.e. forest composition and spatial configuration) while minimizing the confounding influence of climate. Cluster analyses of the 76‐yr time‐series generally grouped by subareas found within the same land management zone. Spatial nonparametric covariance analysis indicated that the highest and lowest degree of spatial synchrony of spruce budworm outbreaks were found within unmanaged wilderness and lands managed at fine spatial scales in Minnesota, respectively. Using multivariate analysis, we also found that forest composition, configuration, and climate together accounted for a total of 40% of the variance in outbreak chronologies, with a high level of shared variance between composition and configuration (13%) and between composition and climate (9%). At the scale of our study, climate on its own did not explain any of the spatial variation in outbreaks. Outbreaks were of higher frequency, lower intensity, and less spatially synchronized in more fragmented, younger forests with a lower proportion of host species, with opposing outbreak characteristics observed in regions characterised by older forests with more concentrated host species. Our study is the first quantitative evaluation of the long‐standing ‘silvicultural hypothesis’ of spruce budworm management specifically conducted at a spatio‐temporal scale for which it was intended.     

Dynamic macroecology on ecological time-scales

Aim The discipline of macroecology is increasingly being regarded as an effective vehicle for the evaluation of recent population‐ to ecosystem‐level responses to widespread human and environmental influences. However, due to the prevalent use of time‐averaged and cumulative data in macroecological analyses, the majority of the patterns that emerge from research in this field can be regarded as static. Here we review the application of dynamic macroecological analyses to changes in relationships between macroecological variables on seasonal to decadal scales. We illustrate the strength of this perspective for documenting changing patterns and testing hypotheses related to these dynamics on ecological time‐scales. Location Studies were compiled and reviewed from terrestrial and aquatic ecosystems. Methods We review examples of temporal changes in macroecological patterns driven by recent anthropogenic influences and environmental change. Results The dynamic nature of macroecological patterns on ecological time‐scales has been revealed in recent years across a wide range of ecosystems, largely through the development, maintenance and analysis of biotic and environmental monitoring time series. The resultant analyses complement examinations of dynamics over evolutionary time and have similarly revealed that static portrayals can conceal important temporal dynamics that underlie the patterns of interest. As a consequence, static depictions, resting as they do on comparative analyses in which the validity of space‐for‐time substitutions is assumed, may be of limited use for testing hypotheses related to the mechanisms underlying the patterns revealed and, by extension, the development of reliable predictions of future states. Main conclusions Recent dynamic macroecological analyses have demonstrated the utility of combined spatial and temporal replication, and have contributed to hypothesis testing related to the mechanistic processes underlying changes in macroecological patterns on ecological time‐scales. We suggest four specific avenues of future research to further the development and application of temporal approaches on similar time‐scales within the field of macroecology.     

Measures of structural complexity in digital images for monitoring the ecological signature of an old-growth forest ecosystem

Conducting field samples for monitoring ecological dynamics across multiple spatiotemporal scales is a difficult task using standard protocols. One alternative is to measure a restricted set of variables which can serve as an ecological orientor (EO) for quantifying habitat change. The objective of this article is to derive from digital images a measure of structural complexity that may serve as a proximate EO for monitoring forest dynamics in space and time. The mean information gain (MIG) index was used as a measure of structural complexity in photographs taken directly in the field over the entire growing season. At a small scene extent, the complexity of light intensity variations in digital images was positively related to species richness. At larger scene extents, forest understorey and overstorey layers showed predictable ecological signatures in structural complexity. In general, intensity and chroma were the two color space components which yielded the greatest sensitivity to habitat change through time. Within the framework of a standardized photographic protocol, it seems therefore reasonable to consider MIG as a suitable EO for monitoring forest dynamics in both space and time. Our results support the idea that it is possible on one hand to adopt a more holistic view of ecological processes to gain, on the other hand, spatial and temporal degrees of freedom for testing multiple scale hypotheses in the field.     

林火干扰对大兴安岭主要林分类型地上生物量预测的影响模拟研究

林火干扰是北方森林最主要的自然干扰之一,对北方森林地上生物量影响是一个长期的过程。因此,在预测地上生物量动态变化时需要考虑林火的影响。运用空间直观景观模型LANDIS PRO,模拟大兴安岭林区林火对不同树种地上生物量预测的影响。选取研究区5种主要树种林分(兴安落叶松、樟子松、云杉、白桦和山杨),以无干扰情景为参考预案,在验证模型模拟结果的基础上,模拟林火在短期(0—50a)、中期(50—150a)和长期(150—300a)对地上生物量的定量化影响,及其对不同立地类型地上生物量的动态变化。结果表明:(1)基于森林调查数据参数化的2000年森林景观模拟结果能够较好地代表2000年真实森林景观,模拟的2010年森林林分密度和胸高断面积与2010年森林调查数据无显著性差异(P0.05),当前林火干扰机制模拟结果能够较好地与样地调查数据匹配,说明林火模拟能够代表当前研究区林火发生情况;(2)与无干扰预案相比,整个模拟时期内景观水平上林火减少了1.7—5.9 t/hm2地上生物量;(3)与无干扰预案相比,林火预案下主要树种生物量在短期、中期和长期变化显著(P0.05);(4)在不同模拟时期,林火显著地改变了地上生物量空间分布,其中以亚高山区地上生物量降低最为明显。研究可为长期森林管理以及森林可持续发展提供参考。     

Role of vegetation in determining carbon sequestration along ecological succession in the southeastern United States

Vegetation plays a central role in controlling terrestrial carbon (C) exchange, but quantifying its impacts on C cycling on time scales of ecological succession is hindered by a lack of long‐term observations. The net ecosystem exchange of carbon (NEE) was measured for several years in adjacent ecosystems that represent distinct phases of ecological succession in the southeastern USA. The experiment was designed to isolate the role of vegetation – apart from climate and soils – in controlling biosphere–atmosphere fluxes of CO₂ and water vapor. NEE was near zero over 5 years at an early successional old‐field ecosystem (OF). However, mean annual NEE was nearly equal, approximately ?450 g C m^?2 yr^?1, at an early successional planted pine forest (PP) and a late successional hardwood forest (HW) due to the sensitivity of the former to drought and ice storm damage. We hypothesize that these observations can be explained by the relationships between gross ecosystem productivity (GEP), ecosystem respiration (RE) and canopy conductance, and long‐term shifts in ecosystem physiology in response to climate to maintain near‐constant ecosystem‐level water‐use efficiency (EWUE). Data support our hypotheses, but future research should examine if GEP and RE are causally related or merely controlled by similar drivers. At successional time scales, GEP and RE observations generally followed predictions from E. P. Odum's ‘Strategy of Ecosystem Development’, with the surprising exception that the relationship between GEP and RE resulted in large NEE at the late successional HW. A practical consequence of this research suggests that plantation forestry may confer no net benefit over the conservation of mature forests for C sequestration.     

Multiple successional pathways in human‐modified tropical landscapes: new insights from forest succession,forest fragmentation and landscape ecology research

Old‐growth tropical forests are being extensively deforested and fragmented worldwide. Yet forest recovery through succession has led to an expansion of secondary forests in human‐modified tropical landscapes (HMTLs). Secondary forests thus emerge as a potential repository for tropical biodiversity, and also as a source of essential ecosystem functions and services in HMTLs. Such critical roles are controversial, however, as they depend on successional, landscape and socio‐economic dynamics, which can vary widely within and across landscapes and regions. Understanding the main drivers of successional pathways of disturbed tropical forests is critically needed for improving management, conservation, and restoration strategies. Here, we combine emerging knowledge from tropical forest succession, forest fragmentation and landscape ecology research to identify the main driving forces shaping successional pathways at different spatial scales. We also explore causal connections between land‐use dynamics and the level of predictability of successional pathways, and examine potential implications of such connections to determine the importance of secondary forests for biodiversity conservation in HMTLs. We show that secondary succession (SS) in tropical landscapes is a multifactorial phenomenon affected by a myriad of forces operating at multiple spatio‐temporal scales. SS is relatively fast and more predictable in recently modified landscapes and where well‐preserved biodiversity‐rich native forests are still present in the landscape. Yet the increasing variation in landscape spatial configuration and matrix heterogeneity in landscapes with intermediate levels of disturbance increases the uncertainty of successional pathways. In landscapes that have suffered extensive and intensive human disturbances, however, succession can be slow or arrested, with impoverished assemblages and reduced potential to deliver ecosystem functions and services. We conclude that: (i) succession must be examined using more comprehensive explanatory models, providing information about the forces affecting not only the presence but also the persistence of species and ecological groups, particularly of those taxa expected to be extirpated from HMTLs; (ii) SS research should integrate new aspects from forest fragmentation and landscape ecology research to address accurately the potential of secondary forests to serve as biodiversity repositories; and (iii) secondary forest stands, as a dynamic component of HMTLs, must be incorporated as key elements of conservation planning; i.e. secondary forest stands must be actively managed (e.g. using assisted forest restoration) according to conservation goals at broad spatial scales.     

A wavelet‐based approach to evaluate the roles of structural and functional landscape heterogeneity in animal space use at multiple scales

The functional relationship between habitat utilization and landscape spatial heterogeneity is fundamental to understanding the spatial nature of animal distribution across scales. Although structural and functional properties of landscape spatial heterogeneity can have different consequences for animal species, few studies have explicitly considered both forms of heterogeneity, partly due to the lack of general methods for direct assessment of scale‐specific associations between variables. We present a wavelet‐based approach to evaluate the roles of structural and functional landscape spatial heterogeneity in animal space use at multiple spatial scales. As a case study, we examined scale‐specific space use patterns of American black bears Ursus americanus in response to structural and functional spatial heterogeneity as well as spatial patterns of vegetation age‐classes in a Canadian boreal forest. We found strong differences in the effects of structural and functional spatial heterogeneity and the scales at which they are associated with the patterns of habitat use by black bears. Functional heterogeneity alone affected space use at 800 and 1600‐m scales, but had significant effects when interacting with structural heterogeneity at 400, 800, and 1600‐m scales. Compared with male bears, female black bears were most sensitive to patterns of forage abundance at intermediate scales, or more specifically, in young and regenerating forests that provide abundant soft mast in boreal forests. Our study highlights the importance of accounting for scale‐dependent properties of (structural and functional) spatial heterogeneity in assessing the ecological effects of landscape components and the effectiveness of the wavelet transform technique in identifying such scale‐specific relationships.