Diatoms: unicellular surrogates for macroalgal community structure in streams?

As wholesale biodiversity assessment is often impractical, the use of surrogates that reflect the assemblage structure and diversity of other taxa has attracted increased attention. We sampled 47 boreal streams for diatoms and macroalgae and examined their assemblage patterns along major environmental gradients. Our main intention was to examine whether diatoms might be useful surrogates for macroalgae in boreal streams. We also assessed whether taxon richness and community composition provided similar insights into the patterns of cross-taxon concordance. According to canonical correspondence analysis, diatom distribution was most strongly related to water pH, conductivity, latitude and longitude, and macroalgal distribution to water pH and iron content, latitude and bed instability. In Mantel’s test, diatoms and macroalgae showed significant cross-taxon concordance. However, there was no significant correlation between taxon richness of the two algal groups, likely reflecting their differing responses to environmental variables. We found evidence that although diatoms and macroalgae are partly controlled by different environmental factors, they are segregated rather similarly along latitude and a few environmental gradients such as water pH and iron content. We conclude that, at least at broad geographical extents and in small streams, diatoms reflect the structure of the macroalgal community and are therefore useful surrogates for cost-effective biomonitoring of algal communities in streams.     

广州市城郊景观的生态演化分析

以广州市郊为例 ,定量地描述了广州市近、中、远郊区景观的结构、功能和发展特征及其所处的生态演化阶段 ,并根据景观动态变化规律 ,最终确定了“自然景观→乡村景观→城乡二元化景观→城乡一体化景观→城市景观”这一城郊景观的自组织生态演化序列     

陕西地区啮齿动物种数分布与生态因子关系的分析

本文初步分析了陕西地区啮齿动物种数分布与生态因子之间的关系。根据自然地理概况,将陕西地区划分为七个啮齿动物地理区。对不同地理区内可能影响啮齿动物种数的４种生态因子与啮齿类物种数之间进行多元线性回归分析。结果表明,气温、降雨量、森林覆盖率及面积与啮齿类物种数之间呈显著正相关。对秦岭、大巴山地区啮齿类的垂直分布也进行了分析。结果表明,啮齿类物种数与海拔高度呈显著负相关。啮齿动物种数与景观类型也有密切关系,景观类型越复杂,啮齿类物种数越丰富。此外,农业活动对啮齿类物种数也有影响,即耕作区种数少于非耕作区。     

生态土地分类研究进展

土地分类是土地评价,替代和管理的基础,对林业资源可持续利用具有重要的意义。生态土地分类是目前土地分类的主要方向和趋势。国际上早已开展此项研究。随着景观生态学和3S技术的发展,生态分类系统的研制已成为生态土地分类的重点。本文对生态土地分类的定义,特点,发展历史,生态分类系统理论,以及国际生态分类系统的发展趋势进行了系统的综述,并指出以资源（森林,土地,水域等）多目标管理为基础,定量与定性相结合的多因子多层次综合是未来生态土地研究发展的总趋势,有必要在我国大力开展相关研究。     

基于边界特征的景观格局分析

通过边界数量的长度谱分布分析。探讨了边界数量-长度特征与景观和组分碎裂化程度之间的相互关系;基于边界的数量和累积长度计算了景观多样性,均匀度、异质性和空间复杂性,并与基于斑快面积比重的传统格局指数计算结果进行了对比分析。研究表明,研究区内的快速城市化过程导致组分界面特征复杂化,空间分布的圈层结构简化;边界总体的数量谱分布方程系数α对于景观整体碎裂化程度有良好的指示意义,基于边界特征的景观格局指数对于传统的格局分析方法可以形成有益的补充。     

An indicator system to assess ecological integrity of managed forests

Ecological integrity of managed forests includes the ability of an ecosystem to support a community of organisms with a similar species composition and functional organization as found in nearby natural systems. We developed an indicator system for ecological integrity based on simulated natural disturbance and indicator species to test if forest condition and habitat in managed forests are similar to that found or expected in natural systems. We then applied the method in an area of the boreal forest (Ontario, Canada) where the objective of Ontario's strategic forest management planning approach is, in part, to conserve ecological integrity through the emulation of the natural disturbance process. Forest condition controls the supply of habitat to support the diversity of native organisms, and historically in boreal forests the natural disturbance process drove forest condition. We selected indicators of forest condition (landscape pattern and compositional mosaic) and habitat function (occupancy rates for a broad range of forest birds), and applied our assessment system to test whether indicators of forest condition and habitat function reflect outcomes expected if natural disturbance processes were successfully emulated. We collected occupancy data in natural and managed forest disturbance types using autonomous acoustic recorders, applied occupancy/detection modeling to estimate corrected occupancy rates (ψ), and then tested for differences in ψ between disturbance types. Some indicators of forest condition were within the range expected under natural disturbance, but we found relatively less old conifer, more young deciduous and greater edge density in managed forests relative to forests of natural disturbance origin. Most species (11 of 14) occurred with equal ψ in habitat originating from the two disturbance types. Brown creeper (Certhia americana), bay-breasted warbler (Mniotilta varia) and red-eyed vireo (Vireo olivaceus) differed between disturbance types. Brown creeper uses older conifer and occurred at lower rates in managed forest, while red-eyed vireo uses a range of deciduous forest ages, and occurred at higher rates in managed forest. Differences in quantity and/or quality of specific habitat types likely explain the responses. The results suggest what directional changes in the forest pattern and compositional mosaic would improve ecological similarity with natural systems, but also indicate what further research is required. We believe this approach to assessing ecological integrity can be adapted to study the effectiveness of conservation management strategies in other systems, and will contribute to adaptive management approaches and evidence-based policy development.     

Deterministic diversity changes in freshwater phytoplankton in the Yunnan–Guizhou Plateau lakes in China

Diversity measures reflect different aspects of a community, which are determined by different ecological processes. However, information is still limited on the ecological processes that are represented by different measures of species diversity. In this study, the primary driving factors for richness and diversity indices were tested. The possible ecological processes represented by each index were analyzed. First, the type of ecological process that governed the phytoplankton community in the Yunnan–Guizhou Plateau lakes, either deterministic or stochastic, was identified by Caswell's neutral model. The results indicate that a deterministic process governs the phytoplankton community. Second, the driving factors of richness and diversity indices were screened with mixed models. The results suggest that the variation of phytoplankton richness in different lakes or sites was primarily related to bottom-up factors. The variations in evenness and other measures based on the relative abundance were driven by both top-down and bottom-up factors, such as zooplankton biomass, and pH and mean light, respectively. Finally, although the different measures of diversity may respond to specific bottom-up or top-down processes, the responses to the two processes were not independent of each other. These findings will increase our understanding of the relationships between ecological processes and diversity measures for freshwater phytoplankton.     

肇庆市景观生态规划研究

肇庆市生态资源丰富,自然保护现状良好,生态环境建设潜力大,但整个生态缺乏合理规划,与经济发展联系不大,对经济发展贡献率低,与旅游规划脱节,致使各地旅游形象不突出,特色不鲜明,景观整体性和连续性遭受破坏,景观、景区间协调不足,过渡不自然,景观视线范围内荒山和采矿点依稀可见,没有充分发挥生态在旅游中的作用。针对以上问题和矛盾,文章对肇庆市景观生态进行功能分区和规划设计,为肇庆市城市规划及景观生态建设提供一定的依据。     

中国1999年生态足迹计算与发展能力分析

可持续发展的定量评估是可持续发展研究的关键领域,其核心是确定人类的生存是否处于生态系统的承载力范围之内．新近提出和发展起来的生态足迹指标是一种测算人类对自然利用程度的新的综合指标,该方法通过将区域的资源和能源消费转化为提供这种物质流所必需的各种生物生产土地的面积(生态足迹),并同区域能提供的生物生产土地面积(生态承载力)进行比较,能定量判断一个区域的发展是否处于生态承载力的范围内．以中国和部分省(区市）1999年的统计数据为基础,对中国和部分省(区市)1999年的生态足迹计算结果表明,1999年中国的人均生态足迹为1．326hm^2,而人均生态承载力为0．681hm^2,人均生态赤字为0、645hm^2;分省的计算结果也表明大部分省(区市)的生态足迹超过了当地的生态承载力．生态赤字的存在表明,区域的经济社会发展处于一种不可持续的发展状态．同时,将生态足迹计算中得到的不同土地类型面积作为测算生态经济系统多样性的指标,测算了中国及部分省(区市)1999年生态足迹的多样性,并采用Ulanowicz的发展能力公式分析了各省的发展能力．发展能力是一个较好的预测产出的指标,增加多样性是增加发展能力的有效途径、另外,还分析了生态足迹的多样性与资源利用效益的关系,讨论了生态足迹及其多样性的政策含义．     

A conceptual framework for ecosystem management based on tradeoff analysis

Three dimensions (natural, social and economic factors) in tradeoff analysis have not been focused in ecology. It is necessary to consider the multi-dimensions through a tradeoff analysis of disturbances to find their positive and negative effects (referred to as two-sidedness). We proposed an 11-step approach to integrate the concepts, methods and examples to understand ecological two-sidedness. We recommend that: (1) ecological complexity and large-scale systematic perspectives need to be integrated; (2) disparate disciplines should be integrated to classify the two-sidedness indicators; (3) models should be adopted to define the characteristic metrics of disturbed ecosystems; (4) researchers need to reconsider evaluation standards and for each indicator with marginal changes; and (5) initial decision-making should refer to the two-sidedness value and that final decision-making should be subject to debate. This approach has great significance for ecosystem management because decision-makers can obtain the superiority and inferiority of disturbance strategies and select optimal strategy.     

Modeling landscape condition for biodiversity assessment—Application in temperate North America

Conservation decisions are well supported by predictive spatial models that indicate the relative ecological condition of a given place. The intent of this 90 m pixel landscape condition model is to use nationally available spatial data from the USA, Mexico, and Canada to express assumptions regarding the relative ecological effects of land uses on terrestrial natural communities and species. This approach emphasizes and updateable and transparent design which takes advantage of empirical biodiversity data from the USA to both calibrate and validate the model. Map layers depicting infrastructure, land use, and modified vegetation were each scored for site impact and distance decay, and then combined into one map surface. Field observations from Natural Heritage Programs, each scored for relative ecological condition (in categories A = excellent to D = poor), were used to calibrate distance decay parameters. Some 90,000 observations for at-risk species, invasive plant species, and natural communities were used for model validation. Statistically significant distinctions in ecological condition among validation samples were predicted by the resultant spatial model. Variation in landscape condition was then summarized by regional U.S. Landscape Conservation Cooperatives (LCCs) in terms of areas approximating A–D condition. Montane and desert LCCs scored on average much higher in area approximating “A” and “B” landscape condition, while LCCs with more substantial agricultural and urban footprints scored overwhelmingly within the “D” range of condition. Similar analyses illustrated range-wide scoring of landscape condition for major vegetation types across temperate North America.     

The ecological reference framework for Québec: a useful tool for forest sites evaluation

Quebec ecologists have divised, for more than 25 years, an integrated landform-soil—vegetation approach to landscape typology and mapping. Basic concepts and principles of this approach are briefly described and illustrated. In spite of the huge areas already mapped, attempts to integrate such an information in the forestry practice have thus far proven inconclusive.     

Multi-scale analysis of butterfly diversity in a Mediterranean mountain landscape: mapping and evaluation of community vulnerability

This paper is an attempt to outline a protocol for animal diversity census and evaluation aimed for areas in view of landscape planning of territories of hundred square kilometres and more, that may work utilising different faunal groups and be anyway useful at various scales. Many papers are addressed to elaborate tools for landscape planning starting from biodiversity evaluation and butterflies are often utilised because of their sensitivity to landscape modifications. In this work, the biodiversity evaluation has been performed using three hierarchically linked landscape units at micro-, meso- and macroscale. Being species diversity values often inadequate to define the conservation interest of a landscape portion, more importance has been given to which species compose the species assemblages. A community vulnerability Index was coded and used for evaluating potential consequences of human disturbance on butterfly assemblages. Forty-four year samples were gained by visual census in the Sila Greca, Southern Italy, on an area of approximately 520 square kilometres. During 5 years work, 2,535 specimens and 94 species were recorded, equal to 75.8% of the whole Calabrian fauna. Four vulnerability levels have been established and used for mapping butterfly assemblage vulnerability in the area, starting from a vegetation map. Species richness was found somewhat contradictory at micro-scale, where the community vulnerability Index gives a sounder approach. S diversity gives a more reliable picture of naturalness at meso-scale, a level we identified with the “ecotope”. At this more “geomorphic” scale level, biological functions reflected by butterfly assemblages revealed to be clearly linked to seral processes. Similarity analysis results show that the ecotope species richness, here called “eta-diversity”, could be an useful measure of zoological landscape (faunation) potentialities.     

基于替代数据思想的复杂度归一化方法及其在心电信号分析中的应用

基于替代数据(Surrogate)思想的复杂度归一化方法,克服了一般复杂度对信号采样长度与采样频率的敏感性。文章对在生物医学信号复杂度分析中最有潜在应用价值的近似熵和C0复杂度进行了归一化。应用该方法可以有效地反映人体心脏某些病理状态之间的差别。同时,通过比较各种复杂度指标发现,C0复杂度和近似熵对采样长度的敏感性最弱,适用于短数据量的信号分析。     

Effects of river level fluctuation on plant species richness, diversity, and distribution in a floodplain forest in Central Amazonia

River levels in Central Amazonia fluctuate up to 14 m annually, with the flooding period ranging from 50 to 270 days between the rising and falling phases. Vast areas of forest along the rivers contain plant species that are well adapted to annual flooding. We studied the effect of flooding level on tree species richness, diversity, density, and composition in lake, river, and stream habitats in Jaú National Park, Brazil. 3051 trees >10 cm diameter (at 1.3 m diameter at breast height, dbh) were measured and identified in 25 10 m × 40 m randomly selected plots in each habitat. Ordination methods and analysis of variance results showed that forested areas near lakes had significantly lower species richness of trees than riverine and streamside habitats. Plot species richness and diversity were strongly negatively correlated with the water level and duration of flooding. The drier (stream) habitat had more total species (54 species of trees) and more unique species of trees (6 tree species) than the riverine (52 tree species; 3 unique species) and lake (33 tree species; 3 unique species) habitats. Species composition overlap among habitats was surprisingly high (42.6–60.6% overlap), almost one-third of the species were found in all three habitat types, and few species were unique to each habitat. We conclude that: (1) duration of flooding has a strong impact on species richness, diversity and plant distribution patterns; (2) most species are adapted to a wide range of habitats and flood durations; and (3) while flood duration may decrease local diversity, it also creates and maintains high landscape-scale diversity by increasing landscape heterogeneity. Received: 20 April 1997 / Accepted: 14 January 1999