试论农业生态系统的多样性

探讨农业生态系统多样性的概念和性质,建立农业生态系统多样性研究的农业生态系统分类方法,研究描述农业生态系统多样性特征的一些指标,提出进一步加强农业生态系统多样性研究的建议。     

基于SOFM网络对黄土高原森林生态系统的养分循环分类研究

对森林生态系统进行分类是认识森林生态过程的根本途径,传统的从结构角度对森林生态系统分类只能反映森林的外在特征,而无法从功能角度区别森林的本质差异.通过对黄土高原3个生物气候区18个不同森林生态系统的养分循环特征测算和分析,选取了能全面反映养分的积累和分布(生物量、枯落物积累量、养分积累量)、循环通量(年吸收量、年存留量、年归还量)以及养分循环效率(循环系数、利用系数、养分生产力)等多方面指标作为分类指标体系,利用自组织映射特征网络(SelfOrganizing Feature Maps,SOFM)聚类方法,从养分循环的角度将黄土高原森林生态系统划分为2个一级类型,6个二级类型.该分类结果与实际较符,从而探索了森林生态系统的功能分类方法,也验证了SOFM网络模型应用于森林养分循环分类的可行性.     

中国农业生态系统多样性保护研究现状与展望

面对气候变化、人口增长和农业集约化等一系列挑战,如何推动农业可持续发展,保障粮食安全,农业生态系统多样性以其独特的遗传、生态和传统社会文化价值成为解决这一难题的重要出路。全面了解农业生态系统多样性的特性、主要影响因子、保护利用措施和研究手段将对制定农业生态系统多样性保护策略具有重要的参考价值。本文研究内容只涉及农业即种植业不是大农业。本文系统分析了各类影响因子和管理措施对农业生态系统多样性的影响,介绍了我国农业生态系统多样性典型生态区域的现状和变化动态,系统阐述了农业生态系统多样性的评估方法,分析了农业生态系统多样性保护和管理的措施,并据此指出我国目前农业生态系统多样性研究的主要问题和今后的展望。分析发现,农业生态系统多样性在维持农业生态服务功能、提高农业生态系统的可恢复力、减少化肥农药污染和发展绿色农业方面发挥着重要的作用。从目前的研究和保护利用情况看,需要完善农业生态系统多样性的评估指标和方法,加强农业生态系统多样性的管理政策和协调机制,加大农业生态系统多样性保护和利用力度,使农业生态系统多样性保护和利用成为主流化。     

基于碳收支的中国土地覆被分类系统

生态系统的碳收支是影响全球变化的重要环节,而土地覆被变化改变了生态系统碳收支的现状、速率。提出了面向碳收支的中国土地覆被分类系统,服务于生态系统碳收支估算和国家生态环境监测。分类系统由一、二级土地覆被类型、三级土地覆被辅助特征构成。通过物质组成、结构、排列、季节特征等19个指标,将土地覆被划分38个二级类型,反映生态系统的碳储量现状。三级土地覆被辅助特征利用9个指标补充了二级土地覆被类型的属性。其中5个环境指标主要反映生态系统碳储备的潜力和强度,土地利用方式指标反映植被演替过程植被碳收支中的人为扰动影响,植被覆盖度、植被生育期、物种特征指标用于进一步细化植被类型。二级类型与三级特征为分层组织的土地覆被产品,有利于产品管理和应用。分类系统已应用到面向全国生态系统碳收支的30m格网的中国土地覆被制图中。     

中国井冈山生态系统多样性

从不同尺度对井冈山生态系统进行了研究分析,并论述生态系统与生物物种多样性的关系,为井冈山生态环境保护与管理提供依据。研究发现,井冈山拥有IUCN/SSC一级生境类型9个,几乎涵盖了除海洋以外的所有生境类型,反映出井冈山生境类型非常丰富。井冈山一级生境中的面积最大的森林是井冈山自然生态系统类型及植被类型的重要基础;灌丛、草地及水域等次要的生境类型,提高了生态系统类型的复杂性和复合性。井冈山的一级生境类型是其生态系统分类的宏观基础,生境类型的丰富程度与生态系统类型的多样性密切相关。根据起源、地貌、生境和属性,以及结构和功能对井冈山生态系统类型进行逐级划分。调查发现,井冈山生态系统类型共有53类,其中自然生态系统21类(包括类型多样的森林生态系统、草地生态系统、静水生态系统等),人工生态系统14类(包括类型多样的人工湿地生态系统、人工林生态系统、农业自然复合生态系统等),复合生态系统18类(包括类型多样的人工复合生态系统、半自然复合生态系统等)。将生态系统只分到四级水平,四级以下还有丰富的生态系统类型。井冈山植物群落可分14个植被型,90个群系,180个群丛。与周围遗产地相比,井冈山的群系数量最多,与面积更大的三清山和武夷山相比,井冈山植被群系数量接近它们的3倍,表现出极其丰富的植被多样性。井冈山物种极其丰富,维管束植物和两栖动物最多,其昆虫数量仅次于武夷山,鸟类数量仅次于丹霞山。井冈山植物物种数最高。虽然井冈山总体空间(分布面积)有限,但这种分化出的丰富的生态位空间使井冈山在有限面积的植被上容纳更多的生物物种成为可能。     

北京市土地利用生态分类方法

本文从国内外土地利用分类体系的现状分析入手,分析了当前土地利用分类体系与生态保护存在的矛盾,提出进行土地利用生态分类。首先,将北京市的土地利用现状类型分析归并为9个一级类15个二级类,确定各土地利用类型基准生态服务价值,然后提出各土地利用类型生态系统服务价值的区位修正方法,在对各种土地利用类型生态系统服务价值进行区位修正的基础上,划分出6个一级生态用地类型。其次,对北京市进行生态适宜性评价,生成生态适宜性分布图,将已生成的土地利用生态一级分类图与生态适宜性分布图进行叠加,对一级生态用地类型进行了二级划分,得到6个大类、18个亚类的北京市土地利用生态用地类型。最后,以北京市2007年的土地利用现状图为例,对北京市的土地利用生态分类方法进行应用,得到了2007年北京市土地利用生态分类图并分析了各土地利用生态用地类型的分布状况。     

泸沽湖生态系统格局变化及其驱动力

运用遥感影像与地理信息系统技术结合,采用生态系统信息分类提取方法和景观指数方法对1990年至2015年泸沽湖风景区生态系统构成与格局变化进行分析,并进一步探析引起各类生态系统变化的驱动力因素,为泸沽湖风景区进一步生态与环境规划提供科学和理论依据。25年间,泸沽湖风景区内主要生态系统类型可分为农田、森林、草地、水域和人居环境等五类生态系统,1990年至2005年,主要表现为农田、森林、草地3个生态系统之间相互转化;2005年至2015年,主要表现为森林、草地、水域生态系统整体流向农田、人居环境系统。总体上泸沽湖景观破碎化与复杂程度呈下降趋势,连通性和整体性逐渐增强,但各生态系统类型之间比例差异增大。农田生态系统变化的主要驱动力是政策导向;森林与草地生态系统变化的主要驱动力是退耕还林还草工程与人类活动;水域生态系统变化主要驱动因素是湿地造林与人类活动入侵;人居环境系统变化的主要驱动因素为人类用地需求的增涨。针对泸沽湖生态系统变化存在的问题提出了相应的规划建议。     

区域生态用地的概念及分类

随着自然资源持续利用的思想、理论逐步深入和发展,生态用地分类及规划研究具有重要意义,成为土地资源利用研究和生态建设工作的重点.总结了国内外生态用地的研究进展,在土地生态系统服务的基础上,提出了生态用地指的是区域或城镇土地中以提供生态系统服务为主的土地利用类型,可将区域土地分为"生态用地"、"生产用地"和"生活用地"三大类型,生态用地按照不同生态系统服务分为自然用地、保护区用地、休养与休闲用地和废弃与纳污用地4个二级类型,进一步分为20个三级类型.生态用地的分类可为建立合理的土地利用生态分类体系和区划提供理论基础.     

农业结构转型对生态系统服务与人类福祉的影响——以西安都市圈两种农业类型为例

研究城市化地区农业类型转变对农业生态系统服务与人类福祉的影响,对调控都市农业发展、维持农业生态系统服务以及提升农户福祉等具有重要意义。以西安都市圈两个农业类型转变的村庄为案例,通过入户调查对村域的生态系统服务价值及人类福祉进行测算,分析农业转型下生态系统服务与人类福祉的相互影响。结果表明:(1)农业结构转型过程中,以粮食耕种为主的马家村的生态系统服务价值由2000年141.88×10~4元减少至2017年117.58×10~4元(降幅为17.13%);而以蔬菜种植为主的火箭村生态系统服务价值由727.23×10~4元增长至1753.23×10~4元(增幅达141.08%),其变化主要源于农业劳动力、农户行为及农业类型的影响。(2)不同农业类型下人类福祉差异明显,以蔬菜种植为主的火箭村人类福祉比以粮食种植为主的马家村高出89%;表明由传统粮食种植转向现代都市农业可以提高人类福祉,在各福祉指标中农业纯收入对农户福祉影响最为显著。(3)不同农业类型下生态系统服务与人类福祉的相关程度不同,但都与农产品供给呈正相关,与农业纯收入呈负相关。以传统粮食种植为主的马家村村民对生态环境的关注度较低,而转向蔬菜种植的火箭村对水质等生态环境的关注度开始提高。生态系统服务价值和农户福祉的提升与农业类型显著相关,因此,可通过政府引导农户规划农业用地类型以优化景观格局,从而维持农业生态系统服务的可持续发展。     

专业化茶叶种植影响下的农业生态系统服务功能价值评价——以福建省安溪县为例

饮茶已逐渐成为世界潮流与时尚,不断扩大的茶叶需求正不断刺激茶叶的增产,茶叶经济发展受到世界瞩目,但关于规模化、专业化茶叶种植对农业生态系统的影响却未得到相应的关注。为研究规模不断扩大的专业化茶叶种植对农业生态系统的影响,以专业化茶叶种植大县安溪县为研究对象,通过构建由供给、调节和支持正、负服务组成的农业生态系统服务功能价值评价指标体系,结合能值法,从不同专业化茶叶种植水平、不同农业种植结构、不同地貌类型三个方面进行评估分析。研究结果表明:(1)安溪县以专业化茶叶种植为主的农业生态系统中供给、调节和支持三大服务功能的正服务价值都大于负服务价值,系统以提供正服务为主;(2)专业化茶叶种植具有较高的经济效益和较好的气体、气候调节能力,对农业生态系统中的供给与调节功能具有正效应;(3)但专业化种植过程中造成的土壤流失情况也较为严重,对农业生态系统支持功能的负面影响较大;(4)"茶-蔬"、"茶-果"等复合生态茶树种植结构有利于提高农业生态系统服务功能,实现茶叶经济与农业生态系统的和谐发展。     

Rice and Remittances: Crop Intensification Versus Labour Migration in Southern Laos

Despite being a low-income, agriculture-based country with a subsistence orientation, Laos is in the early stages of a major economic transformation whereby rural households have been experiencing rapid change in their farming and livelihood systems. Some households have begun to engage in semi-commercial farming while others have adopted labour-oriented or migration-oriented livelihood strategies. This paper explores how rural households in six villages in the lowlands of Champasak Province in southern Laos make a living. These villages vary in their access to irrigation and to markets. Nevertheless, in all villages, long-term migration of younger household members to neighbouring Thailand has come to play a large role in household livelihood strategies. In some cases this is necessary to meet the household’s consumption requirements; in most, it is part of a diversified strategy in which rice farming still plays a significant role, though still largely for subsistence. The paper examines some of the issues involved in attempting to promote intensive, market-oriented rice farming in a context of an emerging on-farm labour shortage combined with an increasing flow of remittances from migrant family members.     

基于生态脆弱性与发展潜力的矿区搬迁村庄识别

矿区村庄搬迁成为煤炭产业发展极为重要的一环,弄清“谁要搬、搬去哪”,对煤矿区的产业发展和生态建设工作尤为重要。选取位于鲁西基地巨野矿区的山东省郓城县作为研究区域,从生态状况和发展状况两角度,基于VSD模型选取表现矿区特点的12个指标构建矿区生态脆弱性评价体系,并以建设水平、经济发展水平和人居环境为准则层选取13个指标构成村庄发展潜力评价体系,结合两者构建矿区搬迁村庄识别体系。结果标明：平原矿区的生态脆弱性受塌陷及煤炭资源储量分类的影响较大,村庄发展潜力整体受交通以及与镇区、中心城区辐射的影响较大;矿区290个村庄划分为优先搬迁、暂缓搬迁、原址保留及安置点选区4个等级,每级分别有72、80、91和47个村庄,占比24.82%、27.59%、31.38%和16.21%。该体系能较细致地识别村庄间差别,为郓城县矿区村庄合理搬迁安置提供借鉴,并具有较好的适用性,为平原煤矿区村庄的搬迁理论发展提供科学有效的参考。     

松嫩平原草原植被分类系统的探讨

 本文在对松嫩平原的草原植被作了全面调查,记录了760多个样方以及对生境,特别是土壤的一些主要因子做了分析的基础上,采用植物与生境和定性与定量相结合的方法;确定以植物种类组成(特别是生态种组)、群落相似性的数量指标和动态特征为依据的分类原则。划分了4个群目、12个群属和40个群丛,建立了三级的分类系统,并阐明各等级分类单位的特征,揭示了松嫩平原草原植物的组合规律及其与环境的关系。不同等级分类单位的相似和差异,体现了分类系统是一个有机的整体和调查区植被的连续性和间断性．此外,分类系统的高级分类单位与立地类型的对应关系,为草原的经营管理提供了依据。     

Typology and ecology of Californian serpentine annual grasslands

Abstract. A first classification for serpentine annual grasslands distributed throughout northern and central California is proposed. This study has followed the Braun‐Blanquet phyto‐sociological system based on floristical, biogeographical and bioclimatic features of the sampled areas. Numerical analyses of classification and ordination were applied to the floristic relevés. Minimum Variance Clustering grouped relevés into basic classification units that allowed us to define low‐hierarchical syntaxonomical units (associations) and ‘communities’. A Principal Coordinate Analysis was used to extract those ecological parameters related to the axes that separate those classification units from the previous dendrogram. The results showed that differences in species composition was mainly due to a continentality gradient and the shady effect of an overstory vegetation. On the basis of both analyses we propose a first syntaxonomic scheme on ultramafic (mainly serpentine) annual plant communities of the biogeographical Californian Region that comprises four associations, two subassociations and some provisional communities.     

Classification of key ecological attributes and stresses of biodiversity for ecosystem-based conservation assessments and management

A whole systems thinking approach to conservation has spawned new approaches in adaptive management planning that require a crucial understanding of what is essential for the functionality of ecosystems and the biodiversity they embrace. In this context, the key ecological attributes (KEA) have been introduced as aspects of a conservation target's biology or ecology that, if missing or altered, would lead to the loss of that target over time. Ecological stresses describe the impaired status of KEAs. Whilst for threats, the drivers of stresses, a systematic classification has been suggested and adopted by IUCN, all existing proposals for stresses and KEAs are preliminary. In order to fill the gap and provide conservation analysts and practitioners with a standard terminology supporting adaptive management planning we suggest a first hierarchical framework and comprehensive classification of key ecological attributes and corresponding stresses to biodiversity. Analyzing 22 vulnerability assessments in 13 countries, spread across 5 continents, as well as an extensive literature review, we identified 144 specific KEAs and stresses. These are differentiated and classified according to three hierarchical levels, 11 KEA and stress classes and 42 general KEAs and stresses. Our classification may help with describing and understanding both the natural functionality and also impaired functioning of biodiversity targets, as well as assist with the development of appropriate conservation strategies. The classification of key ecological attributes is presented as a list but it is important to recognize that the diverse array of KEAs and stresses are systemically interrelated across scales.     

Cultivation of Gracilaria on the sea-bottom in southern Chile: a review

This review contains information about the cultivation techniques, strategies, problems and new challenges faced as well as an economic analysis of the income-producing capacity of Gracilaria farming, considering the variability of environmental systems where this alga is cultivated in southern Chile. The development of Gracilaria farming in Chile was made possible by an increased market demand, as well as the existence of basic knowledge that permitted the management of wild stocks and the initiation of cultivation practices. Subtidal cultivation systems appear to be more productive than intertidal systems and are less susceptible to wave action than intertidal cultivation areas. In relation to farming practices, this difference implies that planting and harvesting methods and strategies vary between habitats where cultivation is being carried out on a commercial scale. Several problems such as the environmental impact of different cultivation methods adopted by the farmers, the management of contaminating organisms and strain selection appear to be important and new areas for future research. Finally, an analysis of the income-producing capacity indicates that environmental differences also have important consequences for the management strategies of Gracilaria cultivation.     

A commentary on muscle unit properties in cat hindlimb muscles

A broad survey of muscle unit properties in 14 muscles of the cat hind limb is presented which emphasizes some general features of unit properties in mammalian muscles. A more detailed analysis of muscle unit properties in three muscles of the posterior compartment of the lower leg is then presented using Burke's tetrapartite (FF, FI or F (Int.), FR, and S) unit classification scheme. Our data on the properties of motor units in cat tibialis posterior (TP) have been compared to those generated by Burke and colleagues on units in flexor digitorum longus (FDL) and medial gastrocnemius (MG). In all three muscles, twitch contraction time was distinctly slower for type S units and specific tension outputs were substantially greater for type FF units than for type S units. The innervation ratios of type FR units were slightly lower than for type S units but the specific tension of the FR units was closer to FF units than to type S units. The FF units controlled 70–74% of the cumulative force output of each muscles, indicating a substantial capacity for powerful rapid contractions of all three of these muscles despite their differences in “size,” action, and force generation. Distinctive features of the three muscles included differences in the unit types' force producing capabilities and in the relative representation of “nonfatigable” type FR and S units in each muscle. In particular, TP is endowed with some unusually powerful type FF units and a high percentage (42%) of type S units. In contrast, FDL has units that develop relatively little force and an unusually high representation (56%) of type FR units. The possible relationships between these muscle features and their presumed role in posture and locomotion is discussed.     

Roles of environmental variables and land usage as drivers of dung beetle assemblage structure in mopane woodland

Colophospermum mopane woodland covers large areas of dry lowland savanna in southeastern Africa. Dominant land usage is conservation (45%) with the remainder mostly modified by farming. Dung beetle responses to environment (dung type, habitat, weather) and land usage (conservation, farming, mining) were examined at Phalaborwa (23.9431°S 31.1411°E) in the Phalaborwa‐Timbavati Mopaneveld, South Africa. Partitioning of gamma species richness and diversity showed lower alpha values in mine areas than in farm and conserved areas. However, between‐land usage differences in species richness, alpha diversity, abundance and biomass, showed lower significance than those between dung type and different weather. At two sampling scales, three multivariate techniques variously separated assemblages according to land usage, dung type and weather. Analysis of 21 mean samples separated clusters according to dung type (Canonical Correspondence Analysis, CCA) or mine assemblages, conserved plus farm assemblages on pig plus elephant, or cattle dung (NMDS, Factor Analysis) with shared variance of >80% and unique variance of 16–18% per cluster. In analysis of 188 samples (CCA), each overlapping dung type cluster was offset in ordinal space with congruent patterns of separation according to land usage and weather (drier days distant from moister days; conserved plus farm areas distant from early succession mine areas, which were distant from disturbed and later succession mine areas). Mining, dung types, and moist conditions were the strongest contributors to between‐assemblage differences. Compared with conserved areas, dung beetle diversity is appreciably altered by mining but only slightly altered by intensive game farming or livestock ranching with subsistence agriculture.     

The classification of wetlands: integration of top-down and bottom-up approaches and their significance for ecosystem service determination

The typology of wetlands provides important information for both water resource managers and conservation planners. One of the most important aims of allocating wetlands to a certain type or class is to provide information about the ecosystem services that the wetland provides. There are two main approaches towards wetland classification. Firstly, there are top-down approaches whereby wetlands are divided into several categories based on a conceptual understanding of how the wetland functions (mostly with regards to water flows). Secondly there are bottom-up approaches whereby the classification of wetlands is based on the collection of data in the wetland that is then subjected to various clustering techniques (mostly with regards to biodiversity). The most utilized system of top-down classification assigns wetlands into hydrogeomorphic units, which function as a single unit in terms of hydrology and geomorphology. This type of classification is most useful for water resource planning, as it provides information about how the wetland is connected to the drainage network and what are the water inflows, throughflows and outflows of the wetland. The bottom-up classification approach typically focusses on the classification of wetland habitats rather than complete wetlands, where wetland habitat represents a spatial unit delineated on the basis of vegetation, embedded within the (complete) hydrogeomorphic unit, and defined as an area of wetland that is homogeneous in terms of opportunities for plant growth. At a broad scale, most ecosystem services can be superficially derived from the hydrogeomorphic unit type and the way water moves through a wetland, but habitat units and the plant species that define them would have a specific effect on the delivery of ecosystem services, for example, with different assemblages providing different resistance to flow. Some types of ecosystem services are exclusively linked to specific wetland habitats, especially provisioning services. For this reason, it is proposed that a combined approach of hydrogeomorphic classification together with a vegetation map, offers the maximum information value for ecosystem service determination. In order to account for the potential pitfall of “double counting” when combining the top-down and bottom-up approaches, each service needs to be considered individually with reference to the degree to which a service is either: (a) primarily determined by HGM class/attributes and modified by the vegetation class/attributes; or (b) primarily determined by the vegetation class/attributes.