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1.
Soil biodiversity includes organisms which spend a part or all of their life cycle on or in the soil. Among soil-dwelling animals, macro-fauna as an important group of animals have important effects on the dynamics of soil organic matter and litter decomposition process. The humus forms interact with the climatic conditions, flora, as well as soil fauna, and microbial activity. In new humus form classifications, soil organisms play an important role in separation of humus horizons from one another. The subject of this study was to determine the diversity of macro fauna for different humus forms. We determined humus forms using morphological classification, and then 69 random samples were taken from plots of 100 cm2 in area, and soil macro-fauna species were collected by hand sorting method. Two classes of humus forms, including Mull (with three humus orders, namely Dysmull, Oligomull, and Mesomull,) and Amphi (with four humus orders, namely Leptoamphi, Eumacroamphi, Eumesoamphi, and Pachyamphi) were identified. A number of 13 macro-fauna orders were identified using identification key. Among the humus orders, Shannon diversity, Simpson evenness and Margalef richness indices were the highest in Pachyamphi order. Arthropod diversity in Pachyamphi humus order was higher than those of Mull. These results showed that diversity of soil macrofauna increase by increasing the thickness of the organic horizons (OL, OF, OH), especially OH horizon. 相似文献
2.
Matthew A. Bowker Fernando T. Maestre Cristina Escolar 《Soil biology & biochemistry》2010,42(3):405-417
Despite that soils may be the greatest repository of biodiversity on Earth, and that most terrestrial ecosystem functions occur in the soil, research on the role of soil biodiversity in ecosystem function has lagged behind corresponding research on aboveground organisms. Soil organisms pose special problems to biodiversity-function research, including the fact that we usually do not know their identity nor what they do in soil ecosystems, cannot easily estimate their biodiversity, and cannot culture the majority of the organisms for use in manipulative experiments. We propose here that biological soil crusts (BSCs) of deserts and many other ecosystems may serve as a useful model system for diversity-function research because the species concept is relatively well-defined within BSC organisms, their functional attributes are relatively well-known, and estimation and manipulation of biodiversity in experiments are feasible, at least within some groups of BSC biota. In spite of these features, there is a pronounced lack of research on biodiversity-function using these organisms. At least two complementary approaches are possible: experiments using artificially-constructed BSCs, and observational studies which statistically control for the effects of other factors which are likely to covary with biodiversity. We applied the latter to four observational datasets collected at multiple spatial scales in Spain and the United States using structural equation models or path analysis using ecosystem function indicators relating to hydrology, trapping and retention of soil resources, and nutrient cycling. We found that, even when total BSC abundance and key environmental gradients are controlled for, direct and approximately linear relationships between species richness and/or evenness and indicators of ecosystem functioning were common. Such relationships appear to vary independently of region or spatial scale, but their strength seems to differ in every dataset. Functional group richness did not seem to adequately capture biodiversity-function relationships, suggesting that bryophyte and lichen components of BSC may exhibit low redundancy. More research employing the multi-trophic, multi-functional, and manipulable BSC system may enable more rapid understanding of the consequences of biodiversity loss in soils, and help enable a biodiversity-function theory that is pertinent to the numerous ecosystem services provided by soil organisms. 相似文献
3.
It has taken time for the international community to accept the idea of biodiversity values, a concept which had previously been restricted to the limited aesthetic and touristic aspects of wildlife. This situation changed following the International Convention on Biodiversity in Rio de Janeiro (1992), which focussed on “the forgotten environmental problem” of biodiversity erosion and made the first clear reference to the values of living species. Biodiversity values refer to direct or indirect, economic or non-economic interest, a given species or ecosystem may represent for human populations. These values are generally split into intrinsic and instrumental (use) values, the last category itself being divided into direct and indirect economic values. Obviously, each of these values carries different weights, and cannot be considered as being weighted equally in terms of justification for species or ecosystem conservation. Soil is probably one of the most species-rich habitats of terrestrial ecosystems, especially if the definition is extended to related habitats like vertebrate faeces, decaying wood, and humus of hollow trees (i.e. epiphytic soils). The diversity of soil communities (sensu lato) thus probably encompasses a large part of terrestrial animals. This highly speciose fauna has been the subject of recent research efforts, and current trends in soil fauna studies include aspects of biology, autecology, ecotoxicology, or functional ecology. During the past 20 years, recognition of the importance of soil fauna in the functioning of soils and by extension of terrestrial ecosystems has been continuously growing, ending in some important applications in agronomy. However, despite the general agreement about the ecological importance of soil fauna and its economic consequences, the absence of concern about this group from conservationists in their studies is conspicuous. This paper aims at presenting soil fauna within the scope of conservation biology concepts, trying to identify the different values of soil fauna and how they participe to the provisioning of key ecosystem services. Finally, the enormous gap between their recognised usefulness and their consideration in protection policies is discussed. 相似文献
4.
5.
The process of designing protected areas to represent all ecosystems in an area adequately is becoming increasingly sophisticated. To date freshwater aquatic ecosystems have seldom been considered in this process. How much of a difference does it make when they are considered as well?This study examined the conservation of riverine biodiversity within 17 assessment units contained by the catchment areas of five perennial rivers flowing through Kruger National Park and two seasonal rivers that are largely contained within this park. Physical river types, fish species and invertebrate families or genera were used as surrogates of riverine biodiversity. Conservation planning software was used to select an optimal set of planning units to represent and maintain riverine biodiversity.The current spatial configuration of Kruger National Park, largely an accident of history, is particularly poor when assessed against the objective of conserving riverine biodiversity. Several alternative layouts are examined. These options are theoretical since there is little current opportunity to reassign land uses in the region. This study shows that substantially improved layouts for both riverine and terrestrial biodiversity are possible, under the constraint of the same total area under protection. The study also shows that even these optimal layouts are only partially successful in efforts to conserve fully representative samples of riverine biodiversity. Because of the longitudinal connectivity of rivers, conservation strategies that extend beyond protected areas are essential. Explicit conservation visions, targets and strategies need to be included in integrated water resource management plans.Based on the results of this study, nine recommendations are provided for increasing the effectiveness of current and future protected areas in conserving riverine biodiversity. These are to use systematic conservation planning to make biodiversity benefits explicit; mend the disconnect between terrestrial and freshwater conservation; use multiple surrogates wherever possible; be strategic about the collection and management of primary data; strive for maximum hydrologic connectivity; resist development pressure; foster good relationships across park fences; where relevant, pursue multi-national cooperation at the basin scale; and engage the value debate and resolve awareness and capacity constraints. 相似文献
6.
Land use is a pervasive influence on most terrestrial ecosystems. Humans are converting natural ecosystems and appropriating an increasingly large portion of the net primary productivity of the Earth’s ecosystems, leaving a rapidly expanding footprint on the environment and threatening the functioning of ecosystems and the ecological services they provide. Understanding the impacts of human activities on the environment from a local to a global scale requires an adequate representation of human modified landscapes and an explanation of the relationships between socioeconomic and biophysical factors. A first step towards this objective is the development of a quantitative measure of the spatial footprint of humans on landscapes, which can then be used as an analytical and monitoring tool for global change, biodiversity and ecosystem studies. Existing approaches have been based mainly on geographic proxies of human influence such as population density, land transformation, accessibility and infrastructure. In this paper, we developed a more comprehensive and spatially-explicit footprint index based on three dimensions: land use intensity, intervention time, and biophysical vulnerability, which we then applied to Colombia as a case study. We found the inclusion of the vulnerability index provided an effective means to address regional variability in biophysical responses to land use impacts. Accounting for the duration of human intervention provided new insights into the relative capacity of ecosystems to recover or be restored. From this knowledge, more appropriate land use policies can be developed. 相似文献
7.
土壤动物在土壤有机质形成中的作用 总被引：2，自引：1，他引：2
作为土壤生态系统重要组成部分的土壤动物,在土壤元素循环转化和迁移过程中发挥着重要的作用。土壤动物是凋落物分解的"微型粉碎机",通过体内"特殊转换器",影响土壤有机质的转化、腐殖质的形成。本文从土壤动物对地表枯落物分解入手,分析了影响土壤动物对凋落物分解的因素,土壤动物通过刺激土壤酶活性,与土壤微生物群落一起,加快土壤有机物的分解,促进土壤腐殖质的转化。旨在拓宽土壤动物生态功能,丰富土壤腐殖质形成机理学说,对保护土壤生物多样性、提高土壤地力、保障粮食安全具有重要的科学意义。 相似文献
8.
Establishment of protected areas in different ecoregions, ecosystems, and diversity hotspots under successive political systems 总被引：1，自引：0，他引：1
Eva-Liis Tuvi Ain Vellak Ülle Reier Robert Szava-Kovats Meelis Pärtel 《Biological conservation》2011,(5):1726-1732
Protected areas are valuable tools for nature conservation but the effectiveness of reserve networks must be monitored continuously. Knowing the history of the establishment of protected areas can help to improve future conservation. We explore how different ecoregions, ecosystems and diversity hotspots have been incorporated in protected areas in Estonia during the last century. We found that the average rate of establishment of protected areas has been surprisingly constant despite profound changes in political systems. However, establishment of protected areas has varied regionally; an agricultural region in south-east Estonia has seen less protection, partly due to lower biodiversity. Wetland ecosystems were initially more placed under protection, whereas recently semi-natural grasslands have gained more attention. In contrast, farmland is under-protected. Surprisingly, biodiversity hotspots were no more protected than the national average. We consider how the development of a protected area network has been influenced by individual persons and public opinion under successive political systems. We suggest that simultaneous gap analysis of ecoregions, ecosystems and diversity hotspots provides a more complete picture than examining a single aspect. Therefore this study can be used as a model for other regions. 相似文献
9.
The concepts and classifications of humus forms developed since the time of scientific pedology formation are critically discussed. The concept of humus forms (types) relates to the classification of a set of topsoil organic and organomineral horizons, which reflects morphologically distinct phases of plant litter and soil organic matter decomposition, but not to the fractions of soil organic matter. Humus forms reflect various types of transformation and accumulation of organic matter in the soil. The stages of development and modern classifications of humus forms abroad are described. The taxonomy of humus forms in Russian literature and its application for the mapping and evaluation of forest soils are considered, as well as its use for the mathematical simulation of soil organic matter mineralization and humification. Prospects for the development of the classification of humus forms in combination with the basic soil classification of European Russia are discussed. A call for an understanding and a common language in soil science at the international level is underlined. 相似文献
10.
Laboratory experiments were conducted using intact collembolan communities, exposed to Madit D®, a phenylurea herbicide (active ingredient isoproturon). Effects were investigated using two distinct humus types, an acid Dysmoder and a neutral Eumull. Within two weeks, no effect of the herbicide was displayed by the Eumull population, while the Dysmoder population was stimulated. When animals were able to escape from the herbicide through a perforated wall separating two compartments filled with natural soil, the behavior of collembolan communities exhibited interactive (non-additive) effects of humus type and herbicide application. The combination of an acid soil (supposedly providing greater tolerance to organic pollutants) with a neutral soil, increased biodiversity of Collembola, but caused the disappearance of some acido-sensitive species, pointing to complex relationships between pesticides, soils and soil organisms. Parallel experiments with single species demonstrated that at the recommended dose Madit D® may cause avoidance effects, but no toxicity. 相似文献
11.
Minna-Liisa Rantalainen Leena Kontiola Hannu Fritze 《Soil biology & biochemistry》2004,36(12):1983-1996
The aim of this field experiment was to explore the combined effects of two factors potentially affecting the local composition of soil decomposer community: resource quality and habitat fragmentation. We created humus (habitat) patches with three different resource quality: (1) pure homogenised humus; (2) humus enriched with needle litter; and (3) humus enriched with needle and leaf litter. These patches were embedded either in a mineral soil matrix, thus representing fragmented habitat, or in natural forest soil, representing continuous (non-fragmented) habitat. The development of faunal (colonisations/extinctions of soil animal populations) and microbial communities in the patches was followed for 12 months. Our results partly supported the hypothesized strong influence of resource quality on the structure of local soil food webs: the abundances of practically all groups of soil fauna, together with biomass of fungi, were higher in the litter-enriched patches than in the pure humus patches. The manifestation and magnitude of the responses of fauna were, however, strongly affected by complex interactions between the characteristics (especially colonisation capacity) of the faunal group in question, habitat quality and time of sampling. In microarthropods and nematodes, the effect of resource quality cascaded up to the predatory level, rendering further support to the existence of strong bottom-up control in soil food webs. Contrary to our expectations, species richness of the communities was not unanimously affected by resource quality. Habitat fragmentation affected the communities only through different number and identity of patch-colonising species in the fragmented and continuous habitat: fragmentation induced no extinctions of species during the experiment at any resource quality level. Consequently, the results indicate that resource quality is more important factor than habitat fragmentation in determining the local structure of communities in soils. On the other hand, colonisation capacities of soil organisms appear to set limits to the exploitation of local resources. 相似文献
12.
Soil can be perceived as a matric system with certain compartments. The mineral, organic, and organomineral matrices can be
distinguished in it. The synthesis of humus in the soil is a continuous process with an abiotic final stage. The synthesis
of polymers takes place on mineral and organomineral matrices. The development of humus horizon considerably reduces the migration
of organic substances in the soil. Three different types of element associations can be distinguished in the soil: the geochemical
association inherited from the parent material, the biochemical association inherited from the remains of living organisms
entering the soil, and the biogeochemical (or proper pedogenic) association appearing in the course of interaction between
the first two element associations under the given type of the soil water regime. The inhibitors and, probably, stimulators
of plant growth also exist in the soil. 相似文献
13.
M. Sheehy Skeffington J. Moran Á. O Connor E. Regan C.E. Coxon M. Gormally 《Biological conservation》2006,133(3):265-290
Turloughs are karst wetland ecosystems that are virtually unique to Ireland. Flooding annually in autumn through springs and fissures in the underlying limestone and draining in the springtime, often through the same fissures or swallow-holes, they have been described as ‘temporal ecotones’. Over 300 have been documented. They are priority habitats in the EU Habitats Directive and support a variety of wet grassland and fen type vegetation. Though the vegetation has been recorded and mapped for over 80 turloughs, records for invertebrates are more sporadic. Characteristic species include some aquatic species-often benefiting from the absence of fish-, and many wetland terrestrial species, including carabid beetles that are rare on a European scale. Due to their shallow nature and the full vegetation cover of the basin, turloughs can host internationally significant numbers of visiting winter wildfowl, particularly whooper swans. The variety of plant and invertebrate communities between turloughs is primarily due to different hydrogeomorphological characteristics, but also depends on the range of grazing practices on turloughs. Since these often vary within a turlough basin, this helps maintain within-turlough biodiversity. The main threat to turloughs in the past was drainage, but pollution by nutrients is also now potentially detrimental. However, a more recent and important threat may be the cessation of farming within turloughs. As potentially threatened wetlands of European importance, turloughs require a full inventory of their biodiversity and the factors affecting it. The collation here of all literature concerning turloughs will provide a basis for an integrated approach to future research on turloughs that is essential for a full understanding of these complex ecosystems. 相似文献
14.
Varsik Martirosyan Racheli Ehrlich Yaffa Frend Gineta Barness Yosef Steinberger 《Pedobiologia》2013,56(4-6):195-203
A fieldwork was carried out in Caesarea sand dunes, Israel, to determine the influence of fine-scale landscape-patch abiotic-factor heterogeneity on microbial activity in a Mediterranean region. Soil organisms in terrestrial systems are unevenly distributed in time and space, and are often aggregated. Spatio-temporal patchiness in the soil environment is thought to be crucial for the maintenance of soil biodiversity, providing diverse microhabitats that are tightly interwoven with resource partitioning. Determination of a ‘scale unit’ to help understand ecological processes has become one of the important and most debatable problems in recent years. To better understand the distribution of soil microbial communities at multiple spatial scales, a survey was conducted to examine the spatial organization of the community structure in two sandy soil ecosystems. One-hundred forty-four soil samples were collected from two patches 4000 m apart from each other. Basal respiration (CO2 evolution without the addition of any external substrate), microbial biomass, functional diversity, and community-level physiological profile (CLPP) in soil were measured with a MicroResp? system. Soil abiotic analysis was performed by soil standard analytical methods. The results demonstrated that bacterial distributions can be highly structured, even within a habitat that appears to be relatively homogeneous at the plot and field scale. Different subsets of the microbial community were distributed differently across the plot. This is due to spatial heterogeneity associated with soil physical, chemical, and biological properties. Although spatial variability in the distribution of soil microorganisms is generally regarded as random, this variability often has a predictable spatial structure. This study provided evidence that a spatially explicit approach to soil ecology can enable the identification of factors that drive the spatial heterogeneity of populations and activities of soil organisms, at scales ranging from meters to hundreds of meters. Furthermore, there is increasing evidence that spatial soil ecology can yield new insights into the factors that maintain and regulate soil biodiversity, as well as on how the spatial distribution of soil organisms influences plant growth and plant community structure. 相似文献
15.
Horizons of humus profiles contain pollen and spores. The palynological information of pollen spectra of terrestrial humus forms must be validated by micropedological knowledge of the processes of infiltration, incorporation, conservation, transport and decay of pollen grains in the soil system. This study presents the results of combined palynological and micromorphological analyses of two mormoder humus forms, sampled in the Forestry Gieten, The Netherlands. The aim of this study was to establish the distribution pattern and life cycle of pollen grains in mormoders. The first step of this cycle of pollen grains in the humus profile is eolian deposition on the soil surface. The second step is incorporation of the grains in organic aggregates in the upper part of the F horizon. In ‘acid’ mormoders, grains are embedded by ageing small excrements of micro-arthropods and incorporated in the resulting organic aggregates. In ‘mild’ mormoders, the same process is observable, but additional pollen grains are also directly incorporated (and slightly transported) in medium excrements of small earthworm. The third step in the cycle is release by microbial attack of the aggregates in the lower part of the F horizon and the H and Ah horizons. The fourth step is re-incorporation of the released grains in organic aggregates of ageing small sized excrements of micro-arthropods, which consume decaying root tissue. Not re-incorporated grains will finally mineralise by microbial consumption. Mineralising of released pollen grains is the main process in the mineral AE horizon. Based on knowledge of the distribution pattern and life cycle of pollen grains in mormoders, pollen diagrams can be used for the reconstruction of the forest development. 相似文献
16.
Freshwaters ecosystems continue to face pressures from pollution, flow regime alterations, habitat destruction and exotic species invasions despite their unique biodiversity. In Europe, National Parks and Special Areas of Conservation aim to provide protection of ‘aggregate’ biodiversity, yet inspection of priority species lists for these sites often reveals a focus towards terrestrial species. In regions such as the Alps and the Pyrénées, this is a particularly serious problem because climate change and other anthropogenic pressures (e.g. hydropower, tourism) are causing widespread hydrological modification which is likely to drive changes in aquatic species abundance, diversity and distribution. Improved understanding of the diversity of rare plants and animals is necessary so efforts can be cost-effectively targeted to conserve the maximum number of species, whilst a clearer picture of these species’ distributions is a precursor to targeting conservation efforts. This paper reports results of a study into the diversity and distribution of 17 endemic mayflies, stoneflies and caddisflies from 598 rivers sites across southern France. Endemic macroinvertebrates were found only at sites in the Pyrénées mountain range with richness peaking at 1500–1800 m above sea level. Nine of these 17 species were recorded from <20 sites and two (Protonemura angelieri, Rhithrogena kimminsi) were found at only 10 sites. Despite both the rarity of these species and threats to their existence, none of them have any current conservation status. New conservation policies for freshwater ecosystems in the French Pyrénées need to be developed as a priority due to the rarity of many aquatic species in this area, growing threats to their existence (habitat modification, hydrological change), and to recognise their importance in food webs that may include other rare species of conservation value. 相似文献
17.
大气氮素沉降研究进展 总被引：13，自引：0，他引：13
人为干扰下的大气氮素沉降已成为全球氮素生物化学循环的一个重要组成部分。作为营养源和酸源, 大气氮沉降数量的急剧增加将严重影响陆地及水生生态系统的生产力和稳定性。本文从大气氮沉降对土壤和水体环境、农业和森林生态系统以及生物多样性等方面综述了近年来国内外大气氮素沉降的研究现状及其对生态系统的影响, 并总结探讨了前人采用的大气沉降氮测定方法, 展望了我国大气氮沉降的研究前景。 相似文献
18.
Lumbricus terrestris L. distribution within an experimental humus mosaic in a mountain spruce forest
An experiment was designed at a mountain site to study the distribution of adult Lumbricus terrestris in relation to a small-scale mosaic of humus forms representative of different stages of a spruce forest ecosystem. Good
agreement was found between distribution in the mosaic and that in the field. ANOVA tests demonstrated the strong influence
of humus form on earthworm abundance when comparing a vermimull (high earthworm burrowing activity) taken from a spruce regeneration
site (61.8 individuals m–2) with a leptomoder (no earthworm burrowing activity) taken from a 60-year-old spruce stand (6.2 individuals m–2). Other humus forms were intermediate (mean density 34.6 individuals m–2). The same pattern was found with individual biomass, but with lower significance. Main differences observed in the experimental
design were attributed to the immediate carrying density of the humus forms. A distinction was made between humus profiles
built up with or without spruce cover. In the latter case (regeneration site and bilberry heath), the immediate carrying capacity
indicated by the experimental approach overestimated the field density by a factor of 4. Under spruce this overestimate was
even higher (approximately 10 times too high in an adult spruce stand (160 years old) and 30 times too high under moss cover).
The increase in density due to experimental conditions was not determined for leptomoder humus accumulated under the actively
growing spruce stand (60 years old) since the earthworm density was near zero in both cases. Relationships between humus form
and earthworm populations are discussed.
Received: 9 June 1997 相似文献
19.
A study was carried out on some basic characteristics of the organic matter in the surface horizons of soils from the two different geological (calcareous and acid metamorphic rocks) and ecological systems under a Mediterranean climate in Southeast Spain. The results show some noticeable differences in soil organic matter composition. This is likely due to typical Mediterranean climate and well adapted vegetation. There is a tendency towards a greater stability for the soil humus formed under slightly alkaline soil in comparison to the slightly acidic environment. The samples taken from the latter environment have a higher content in free organic matter, a lower content in total extractable humin and a greater relative proportion of aliphatic chains and lignin in the humic acids. The results also suggest some differences caused by the type of vegetation (forest and scrubland ecosystems) in the soil humus chemistry, with a more obvious negative effect under reforestations with species of Pinus in an acidic soil environment (a higher content in free organic matter, lesser presence of fungal-derived perylenequinonic pigments in the humic acids, and a higher content in little evolved forms of nitrogen and lignin in the humic acids). In general the organic matter under scrubland and Quercus vegetation is more decomposed and the humus is more evolved than under Pinus vegetation. 相似文献
20.
THE CATEGORIES OF ALUMINIUM- AND IRON-HUMUS COMPLEXES IN ANDO SOILS DETERMINED BY SELECTIVE DISSOLUTION 总被引：2，自引：0，他引：2
Thirty-three samples of Ando soils were extracted by sodium pyrophosphate (O.IM; pH 10) and by dithionite-citrate. The Al, Fe, and C contents of these two extracts offer a means of differentiating the status of humus in relation to Al and Fe in the different horizons. The humus that forms at first in the Al horizon has a very low complexing ability for Al and Fe and little is dissolved by pyrophosphate. The humus evolves with time or pedogenesis into forms that complex Al and Fe released from volcanic ash by weathering, and which are dissolved by pyrophosphate. In the old horizons, the humus further reacts with additional Al and Fe, some of which may be present as hydrous oxides or allophane-like constituents, allophane and imogolite. This reaction probably makes the humus less soluble in pyrophosphate. 相似文献