Fractal properties of forest spatial structure

The definition of fractal dimension of natural objects, which enables to deal with scale dependence of fractal dimension is discussed. Abrupt changes of fractal dimension of spatial structure of terrestrial ecosystems are considered in the context of hierarchical paradigm. On this ground the procedure is proposed for segmentation of a territory, which takes into account the scale dependence of spatial variability of ecological parameters. Using remotely sensed data — normalized difference vegetation index (NDVI) and thermal radiation in the infrared band — fractal dimensions and critical scales are evaluated for different forest types with the help of software, developed for this purpose. The results obtained corroborate the potentialities of fractal approach in ecology. These methods and results can be used for discrimination of remotely sensed data; but further investigations, including detailed comparison of fractal characteristics of remotely sensed forest images with results of on-site field studies are necessary to validate them.     

Statistical ecology comes of age

The desire to predict the consequences of global environmental change has been the driver towards more realistic models embracing the variability and uncertainties inherent in ecology. Statistical ecology has gelled over the past decade as a discipline that moves away from describing patterns towards modelling the ecological processes that generate these patterns. Following the fourth International Statistical Ecology Conference (1–4 July 2014) in Montpellier, France, we analyse current trends in statistical ecology. Important advances in the analysis of individual movement, and in the modelling of population dynamics and species distributions, are made possible by the increasing use of hierarchical and hidden process models. Exciting research perspectives include the development of methods to interpret citizen science data and of efficient, flexible computational algorithms for model fitting. Statistical ecology has come of age: it now provides a general and mathematically rigorous framework linking ecological theory and empirical data.     

Fractal geometry is heritable in trees

Understanding the genetic basis to landscape vegetation structure is an important step that will allow us to examine ecological and evolutionary processes at multiple spatial scales. Here for the first time we show that the fractal architecture of a dominant plant on the landscape exhibits high broad-sense heritability and thus has a genetic basis. The fractal architecture of trees is known to influence ecological communities associated with them. In a unidirectional cottonwood-hybridizing complex (Populus angustifolia x P. fremontii) pure and hybrid cottonwoods differed significantly in their fractal architecture, with phenotypic variance among backcross hybrids exceeding that of F1 hybrids and of pure narrowleaf cottonwoods by two-fold. This result provides a crucial link between genes and fractal scaling theory, and places the study of landscape ecology within an evolutionary framework.     

生态学中的尺度问题：内涵与分析方法

尺度问题已成为现代生态学的核心问题之一.尺度问题主要涉及3个方面：尺度概念、尺度分析和尺度推绎.主要评述前两个方面.生态学尺度有三重概念：维数、种类和组分,其中每重概念又包含了多个定义,有必要进行澄清、分类和统一.尺度分析涉及尺度效应分析和多尺度空间格局分析.格局、过程及它们之间的关系,以及某些景观特性均表现出尺度效应,因此多尺度研究非常必要和重要.多尺度空间格局分析（尤其是特征尺度的识别）是进行尺度效应分析和跨尺度推绎的基础.多尺度分析需要特定的方法,景观指数法是最常用和最简单的方法,但也常产生误导;空间统计学方法（如半方差分析法、尺度方差分析法、空隙度指数法和小波分析法等）和分维分析法在最近十几年发展起来,并逐渐应用于生态学,在尺度分析上具有很大的应用潜力.各种方法在尺度分析上各有优势和不足,有必要同时使用两种或两种以上方法进行比较和评估.总之,有关尺度分析的研究需要进一步加强,从而为下一步的尺度推绎提供可靠的依据.     

Statistical mechanics unifies different ecological patterns

Recently there has been growing interest in the use of maximum relative entropy (MaxREnt) as a tool for statistical inference in ecology. In contrast, here we propose MaxREnt as a tool for applying statistical mechanics to ecology. We use MaxREnt to explain and predict species abundance patterns in ecological communities in terms of the most probable behaviour under given environmental constraints, in the same way that statistical mechanics explains and predicts the behaviour of thermodynamic systems. We show that MaxREnt unifies a number of different ecological patterns: (i) at relatively local scales a unimodal biodiversity-productivity relationship is predicted in good agreement with published data on grassland communities, (ii) the predicted relative frequency of rare vs. abundant species is very similar to the empirical lognormal distribution, (iii) both neutral and non-neutral species abundance patterns are explained, (iv) on larger scales a monotonic biodiversity-productivity relationship is predicted in agreement with the species-energy law, (v) energetic equivalence and power law self-thinning behaviour are predicted in resource-rich communities. We identify mathematical similarities between these ecological patterns and the behaviour of thermodynamic systems, and conclude that the explanation of ecological patterns is not unique to ecology but rather reflects the generic statistical behaviour of complex systems with many degrees of freedom under very general types of environmental constraints.     

景观格局与生态过程的耦合研究:传承与创新

景观格局与生态过程的耦合关系是景观生态学研究的核心主题,耦合研究的范围和程度需要进一步系统梳理。从景观格局与生态过程耦合的内涵、方法等方面,系统总结了当前两者研究的特点以及存在问题。进一步从格局-过程耦合基本理论传承与提升、研究方法现代化和多元化、研究尺度多样化、研究对象的扩展与集成、自然-人文-社会视角的耦合、格局-过程耦合的管理和调控等六个方面展望了未来学科发展方向。最后,提出了未来创新目标,如提高景观格局量化的准确性和针对性、辨明景观格局影响的尺度性、增强生态过程模拟的时效性等。     

环境DNA技术在地下生态学中的应用

地下生态过程是生态系统结构、功能和过程研究中最不确定的因素。由于技术和方法的限制,作为"黑箱"的地下生态系统已经成为限制生态学发展的瓶颈,也是未来生态学发展的主要方向。环境DNA技术,是指从土壤等环境样品中直接提取DNA片段,然后通过DNA测序技术来定性或定量化目标生物,以确定目标生物在生态系统中的分布及功能特征。环境DNA技术已成功用于地下生态过程的研究。目前,环境DNA技术在土壤微生物多样性及其功能方面的研究相对成熟,克服了土壤微生物研究中不能培养的问题,可以有效地分析土壤微生物的群落组成、多样性及空间分布,尤其是宏基因组学技术的发展,使得微生物生态功能方面的研究成为可能;而且,环境DNA技术已经在土壤动物生态学的研究中得到了初步应用,可快速分析土壤动物的多样性及其分布特征,更有效地鉴定出未知的或稀少的物种,鉴定土壤动物类群的幅度较宽;部分研究者通过提取分析土壤中DNA片段信息对生态系统植物多样性及植物分类进行了研究,其结果比传统的植物分类及物种多样性测定更精确,改变了以往对植物群落物种多样性模式的理解。同时,环境DNA技术克服传统根系研究方法中需要洗根、分根、只能测定单物种根系的局限,降低根系研究中细根区分的误差,并探索性地用于细根生物量的研究。主要综述了基于环境DNA技术的分子生物学方法在土壤微生物多样性及功能、土壤动物多样性、地下植物多样性及根系生态等地下生态过程研究中的应用进展。环境DNA技术对于以土壤微生物、土壤动物及地下植物根系为主体的地下生态学过程的研究具有革命性意义,并展现出良好的应用前景。可以预期,分子生物学技术与传统的生态学研究相结合将成为未来地下生态学研究的一个发展趋势。     

Phylogeny, ecology, and the coupling of comparative and experimental approaches

Recent progress in the development of phylogenetic methods and access to molecular phylogenies has made comparative biology more popular than ever before. However, determining cause and effect in phylogenetic comparative studies is inherently difficult without experimentation and evolutionary replication. Here, we provide a roadmap for linking comparative phylogenetic patterns with ecological experiments to test causal hypotheses across ecological and evolutionary scales. As examples, we consider five cornerstones of ecological and evolutionary research: tests of adaptation, tradeoffs and synergisms among traits, coevolution due to species interactions, trait influences on lineage diversification, and community assembly and composition. Although several scenarios can result in a lack of concordance between historical patterns and contemporary experiments, we argue that the coupling of phylogenetic and experimental methods is an increasingly revealing approach to hypothesis testing in evolutionary ecology.     

Niche conservatism as an emerging principle in ecology and conservation biology

The diversity of life is ultimately generated by evolution, and much attention has focused on the rapid evolution of ecological traits. Yet, the tendency for many ecological traits to instead remain similar over time [niche conservatism (NC)] has many consequences for the fundamental patterns and processes studied in ecology and conservation biology. Here, we describe the mounting evidence for the importance of NC to major topics in ecology (e.g. species richness, ecosystem function) and conservation (e.g. climate change, invasive species). We also review other areas where it may be important but has generally been overlooked, in both ecology (e.g. food webs, disease ecology, mutualistic interactions) and conservation (e.g. habitat modification). We summarize methods for testing for NC, and suggest that a commonly used and advocated method (involving a test for phylogenetic signal) is potentially problematic, and describe alternative approaches. We suggest that considering NC: (1) focuses attention on the within‐species processes that cause traits to be conserved over time, (2) emphasizes connections between questions and research areas that are not obviously related (e.g. invasives, global warming, tropical richness), and (3) suggests new areas for research (e.g. why are some clades largely nocturnal? why do related species share diseases?).     

PHYLOGENETIC,ECOLOGICAL, AND ALLOMETRIC CORRELATES OF CRANIAL SHAPE IN MALAGASY LEMURIFORMS

Adaptive radiations provide important insights into many aspects of evolution, including the relationship between ecology and morphological diversification as well as between ecology and speciation. Many such radiations include divergence along a dietary axis, although other ecological variables may also drive diversification, including differences in diel activity patterns. This study examines the role of two key ecological variables, diet and activity patterns, in shaping the radiation of a diverse clade of primates, the Malagasy lemurs. When phylogeny was ignored, activity pattern and several dietary variables predicted a significant proportion of cranial shape variation. However, when phylogeny was taken into account, only typical diet accounted for a significant proportion of shape variation. One possible explanation for this discrepancy is that this radiation was characterized by a relatively small number of dietary shifts (and possibly changes in body size) that occurred in conjunction with the divergence of major clades. This pattern may be difficult to detect with the phylogenetic comparative methods used here, but may characterize not just lemurs but other mammals.     

Fractal analysis provides new insights into the complexity of marine mammal behavior: A review,two methods,their application to diving and surfacing patterns,and their relevance to marine mammal welfare assessment

Fractals have been applied to describe the complexity of behavioral displays in a range of organisms. Recent work suggests that they may represent a promising tool in the quantification of subtle behavioral responses in marine mammals under chronic exposure to disturbance. This paper aims at introducing the still seldom used fractals to the broader community of marine mammal scientists. We first briefly rehearse some of the fundamental principles behind fractal theory and review the previous uses of fractals in marine mammal science. We subsequently introduce two methods that may be used to assess the complexity of marine mammal diving patterns, and we apply them to the temporal dynamics of the diving patterns of killer whales in the presence and absence of sea kayaks, the sequential behavior of harbor and gray seals in environments with distinct levels of anthropogenic influence, and southern right whales with and without calves. We discuss the ecological relevance of identifying fractal properties in marine mammal behavior, and the potential strength of the fractal behavioral parameters in comparison to more standard behavioral metrics. We finally briefly address the relevance fractal methods may have for the design and implementation of management and conservation strategies.     

Fractal Gait Patterns Are Retained after Entrainment to a Fractal Stimulus

Previous work has shown that fractal patterns in gait can be altered by entraining to a fractal stimulus. However, little is understood about how long those patterns are retained or which factors may influence stronger entrainment or retention. In experiment one, participants walked on a treadmill for 45 continuous minutes, which was separated into three phases. The first 15 minutes (pre-synchronization phase) consisted of walking without a fractal stimulus, the second 15 minutes consisted of walking while entraining to a fractal visual stimulus (synchronization phase), and the last 15 minutes (post-synchronization phase) consisted of walking without the stimulus to determine if the patterns adopted from the stimulus were retained. Fractal gait patterns were strengthened during the synchronization phase and were retained in the post-synchronization phase. In experiment two, similar methods were used to compare a continuous fractal stimulus to a discrete fractal stimulus to determine which stimulus type led to more persistent fractal gait patterns in the synchronization and post-synchronization (i.e., retention) phases. Both stimulus types led to equally persistent patterns in the synchronization phase, but only the discrete fractal stimulus led to retention of the patterns. The results add to the growing body of literature showing that fractal gait patterns can be manipulated in a predictable manner. Further, our results add to the literature by showing that the newly adopted gait patterns are retained for up to 15 minutes after entrainment and showed that a discrete visual stimulus is a better method to influence retention.     

Ecological plant epigenetics: Evidence from model and non‐model species,and the way forward

Growing evidence shows that epigenetic mechanisms contribute to complex traits, with implications across many fields of biology. In plant ecology, recent studies have attempted to merge ecological experiments with epigenetic analyses to elucidate the contribution of epigenetics to plant phenotypes, stress responses, adaptation to habitat, and range distributions. While there has been some progress in revealing the role of epigenetics in ecological processes, studies with non‐model species have so far been limited to describing broad patterns based on anonymous markers of DNA methylation. In contrast, studies with model species have benefited from powerful genomic resources, which contribute to a more mechanistic understanding but have limited ecological realism. Understanding the significance of epigenetics for plant ecology requires increased transfer of knowledge and methods from model species research to genomes of evolutionarily divergent species, and examination of responses to complex natural environments at a more mechanistic level. This requires transforming genomics tools specifically for studying non‐model species, which is challenging given the large and often polyploid genomes of plants. Collaboration among molecular geneticists, ecologists and bioinformaticians promises to enhance our understanding of the mutual links between genome function and ecological processes.     

植被演替过程中种群格局动态的分形分析

该文根据“空间代替时间”的原则和对马尾松(Pinus massoniana)种群的重要值-平均胸径的变动趋势的分析,确定5个森林群落为广东省黑石顶自然保护区森林群落演替的一个时间序列;并在此基础上,运用分形理论的计盒维数和信息维数,对演替过程中马尾松种群空间格局的动态进行了分形分析。结果表明,马尾松种群的计盒维数和信息维数2个参数值均呈递减趋势,与其个体数、重要值变动趋势一致。在群落的演替过程中,马尾松种群的空间占据能力不断下降,种群呈衰退趋势。随其在群落中的优势地位逐渐被其它种群取代,群落将由以马尾松占绝对优势的单优群落演替为多优常绿阔叶林群落。分析结果同时表明,分形分析是群落演替过程中种群空间格局动态研究的有效方法,分形维数则能反映种群格局的尺度变化规律。     

城市景观功能的区域协调规划——以深圳市为例

城市景观功能的完善是城市可持续发展的重要保障之一,其与区域景观功能的相互协调是城市规划的重要组成部分,有利于城市和区域的整体持续发展。在分析城市景观基本特征的基础上,探讨了城市景观功能区域协调规划的基本思路,以城市景观为规划对象,以人类社会的功能需求为立足点,依据景观生态学理论,将城市景观的功能划分为生物生产功能、环境服务功能、文化支持功能和信息输运功能,对体现这些基本功能的景观类型进行区域协调规划。以深圳市为例,实证分析了其景观功能在珠江三角洲地区的协调规划。     

Vagility: The Neglected Component in Historical Biogeography

The conceptual gap between ecological and historical biogeography is wide, although both disciplines are concerned with explaining how distributions have been shaped. A central aim of modern historical biogeography is to use a phylogenetic framework to reconstruct the geographic history of a group in terms of dispersals and vicariant events, and a number of analytical methods have been developed to do so. To date the most popular analytical methods in historical biogeography have been parsimony-based. Such methods can be classified into two groups based on the assumptions used. The first group assumes that vicariance between two areas creates common patterns of disjunct distributions across several taxa whereas dispersals and extinctions generate clade specific patterns. The second group of methods assumes that passive vicariance and within-area speciation have a higher probability of occurrence than active dispersal events and extinction. Typically, none of these methods takes into account the ecology of the taxa in question. I discuss why these methods can be potentially misleading if the ecology of the taxon is ignored. In particular, the vagility or dispersal ability of taxa plays a pivotal role in shaping the distributions and modes of speciation. I argue that the vagility of taxa should be explicitly incorporated in biogeographic analyses. Likelihood-based methods with models in which more realistic probabilities of dispersal and modes of speciation can be specified are arguably the way ahead. Although objective quantification will pose a challenge, the complete ignorance of this vital aspect, as has been done in many historical biogeographic analyses, can be dangerous. I use worked examples to show a simple way of utilizing such information, but better methods need to be developed to more effectively use ecological knowledge in historical biogeography.     

景观生态网络研究进展

作为生态学重要的概念与方法,生态网络是景观生态学研究的热点问题,也是耦合景观结构、生态过程和功能的重要途径。景观生态网络对于保护生物多样性、维持生态平衡、增加景观连接度具有重要意义。从景观生态网络的相关理论、研究进展、研究方法模型等进行分析,并对其应用前景进行展望,主要介绍了传统景观格局分析、网络分析、模型模拟等方法的适用性与特点,并分析了景观生态网络在城市景观格局优化、自然保护区规划、生物多样性保护、土地规划等领域的应用,最后提出了研究的主要问题。     

Integrating the statistical analysis of spatial data in ecology

In many areas of ecology there is an increasing emphasis on spatial relationships. Often ecologists are interested in new ways of analyzing data with the objective of quantifying spatial patterns, and in designing surveys and experiments in light of the recognition that there may be underlying spatial pattern in biotic responses. In doing so, ecologists have adopted a number of widely different techniques and approaches derived from different schools of thought, and from other scientific disciplines. While the adaptation of a diverse array of statistical approaches and methodologies for the analysis of spatial data has yielded considerable insight into various ecological problems, this diversity of approaches has sometimes impeded communication and retarded more rapid progress in this emergent area. Many of these different statistical methods provide similar information about spatial characteristics, but the differences among these methods make it difficult to compare the results of studies that employ contrasting approaches. The papers in this mini-series explore possible areas of agreement and synthesis between a diversity of approaches to spatial analysis in ecology.     

Stable Isotope Techniques and Applications for Primatologists

Stable isotope biogeochemistry is useful for quantifying the feeding ecology of modern and extinct primates. Over the past three decades, substantial advances have been made in our knowledge of the physiological causes of isotopic patterns as well as effective methodology to prepare samples for isotopic analysis. Despite these advances, the potential of stable isotope biogeochemistry has yet to be fully exploited by primate researchers, perhaps due to the prolific and somewhat daunting nature of the isotopic literature. I here aim to present a cogent overview of stable isotope applications to nonhuman primate feeding ecology. I review the factors that influence ecological patterns in carbon, nitrogen, and oxygen stable isotopes. I present methods for collecting and preparing samples of tooth enamel and bone mineral hydroxyapatite, bone collagen, fur and hair keratin, blood, feces, and urine for isotope analysis. I discuss both the existing and potential applications of these isotopic patterns to primate feeding ecology. Lastly, I point out some of the pitfalls to avoid when interpreting and comparing isotopic results.