共查询到20条相似文献，搜索用时 35 毫秒
1.
Richard Frankham 《Biological conservation》2010,143(9):1919-1927
I discuss future challenges and opportunities in genetic approaches to biodiversity conservation. Resolving taxonomy uncertainties and identifying diverged evolutionary units within species are both bedevilled by a plethora of definitions: the challenge for the conservation community is to come to an agreed definition of species and for a unit within species for conservation purposes. For genetic management in the wild, the main challenge is to apply well-established genetic principles to management, especially of fragmented populations. Fears about outbreeding depression are preventing rational use of gene flow for genetic rescue; predicting the risk of outbreeding depression is the most important unmet scientific challenge in the field. The major challenge in genetic management of captive populations of threatened animal species is to institute explicit management to minimize genetic adaptation to captivity, so that reintroduction success is maximized. The development of low cost genome sequencing offers many research opportunities and challenges. For example, there are opportunities to identify genes involved in speciation and a major challenge is to devise molecular tests to predict reproductive isolation between populations. Genomics offers opportunities to provide higher precision estimate for many parameters of importance to conservation. A major challenge is to devise means to assess, on a genome-wide basis, genetic diversity that is important to adaptive evolution. There is a challenge to develop simple inexpensive means to monitor genetic diversity of species on a global scale. Many of the most important practical challenges concern application of current genetic knowledge to the management of threatened species. 相似文献
2.
Assessing bacterial diversity in soil 总被引：1，自引：1，他引：0
3.
P. V. Krasilnikov M. I. Gerasimova D. L. Golovanov M. V. Konyushkova V. A. Sidorova A. S. Sorokin 《Eurasian Soil Science》2018,51(1):1-13
Methodological basics of the study and quantitative assessment of pedodiversity are discussed. It is shown that the application of various indices and models of pedodiversity can be feasible for solving three major issues in pedology: a comparative geographical analysis of different territories, a comparative historical analysis of soil development in the course of landscape evolution, and the analysis of relationships between biodiversity and pedodiversity. Analogous geographic concepts of geodiversity and landscape diversity are also discussed. Certain limitations in the use of quantitative estimates of pedodiversity related to their linkage to the particular soil classification systems and with the initial soil maps are considered. Problems of the interpretation of the results of pedodiversity assessments are emphasized. It is shown that scientific explanations of biodiversity cannot be adequately applied in soil studies. Promising directions of further studies of pedodiversity are outlined. They include the assessment of the functional diversity of soils on the basis of data on their properties, integration with geostatistical methods of evaluation of soil variability, and assessment of pedodiversity on different scales. 相似文献
4.
Boris Schröder 《植物养料与土壤学杂志》2008,171(3):325-337
5.
V. A. Terekhova 《Eurasian Soil Science》2011,44(2):173-179
The methodological and organizational problems of the practical application of soil bioassay to monitor the state of soils
for environmental, agricultural, and sanitary-epidemiological purposes are analyzed. To improve the efficiency of the integral
valuation of soil toxicity, soil bioassay should be performed with a set of organisms (sensors) representing the major trophic
levels of the ecosystems, i.e., producers, consumers, and decomposers. 相似文献
6.
Jean-François Ponge 《Soil biology & biochemistry》2003,35(7):935-945
Humus forms are the seat of most biological transformations taking place in terrestrial ecosystems, being at the interface between plants, animals and microbes. The diversity of terrestrial humus forms (mor, moder and mull) can be attributed to the existence of different patterns (strategies) for the capture and use of resources by ecosystems, in ascending order of biodiversity and bioavailability. Arguments are found in the parallel development of humus forms and terrestrial ecosystems, in exclusion mechanisms between organisms living in different humus forms, and in palaeontological studies. The diversification of terrestrial life forms in the course of Earth history, concomitant with an improvement in resource availability due to the development of sedimentary layers at the surface of continents, may explain the successive appearance of more active humus forms enabling the co-existence of an increasing number of organisms. Contradictory reports about the relationships between biodiversity and stability of ecosystems can be explained by the existence of different belowground pathways making ecosystems more stable. 相似文献
7.
Soils are the central organizing entities in terrestrial ecosystems and possess extremely diverse prokaryotic and eukaryotic biota. They are physically and chemically complex, with micro- and macro-aggregates embedded within a solid, liquid and gaseous matrix that is continually changing in response to natural and human-induced perturbations. Recent advances in molecular techniques in systematics have provided opportunities for the study of biodiversity and biocomplexity of soil biota. A symposium and workshop on soil biogeochemistry and biodiversity International Symposium on Impacts of Soil Biodiversity on Biogeochemical Processes in Ecosystems, Taiwan Forestry Research Institute, Taipei, Taiwan April 18-24, 2004. Convened an international array of participants working in biomes on virtually every continent on the planet (ranging from polar to tropical regions). This special issue reports on the theoretical bases and applications of molecular methods for the measurement of soil biodiversity.
Themes addressed include a melding of classical taxonomic investigations with biochemical fingerprinting and molecular probing of organism identities. Several papers highlight new advances in identifications of prokaryotic and eukaryotic organisms. Examples include new developments in “fingerprinting” of microbes active in “mycorrhizospheres” using immunocapture and other innovative techniques. Developments in the study of impacts of invasive plant and animal species on ecosystem function and subsequent microbial community composition and function have been very great in the last 2-3 years. Soils are major repositories of legacies, including fine and coarse woody debris and other organic products, which have feedbacks on soil diversity. The ways in which species diversity and function of microbial and faunal communities interact and their importance to ecosystem function are examined in biological and biochemical detail. This paper provides an overview of soil biodiversity and its feedbacks on soil biogeochemical processes in ecosystems. 相似文献
8.
“十四五”土壤生物学分支学科发展战略 总被引：3，自引：1，他引：2
土壤生物是地球生物多样性的重要组成部分。土壤生物驱动着土壤中有机质降解、元素循环、污染物转化与降解以及温室气体的产生与消耗,在全球粮食安全、环境保护以及应对气候变化等方面发挥着重要作用。土壤生物学是研究土壤生物多样性与分布、土壤生物的过程与功能以及土壤生物的调控与应用的科学。21世纪以来,分子生物学技术的突破与生态学理论的广泛应用极大地推进了土壤生物学研究的发展。本文回顾了土壤生物学科的发展历程,详细介绍了土壤生物学科的发展现状,提出了土壤生物学科在理论与应用上的发展趋势,并对未来土壤生物学科的发展方向进行了展望。随着多学科交叉融合以及研究手段的进步,土壤生物学迎来了一个新的发展时期。土壤生物学研究在生物资源挖掘、时空分布格局、生态服务功能和生物调控等方面取得的重要成果,将更好地服务于土壤健康、植物健康、人类健康以及我们的星球健康。 相似文献
9.
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
10.
Erin J. Questad Bryan L. Foster Suneeti Jog Kelly Kindscher Hillary Loring 《Biological conservation》2011,(3):1050-1058
Market and policy incentives that encourage agricultural intensification, such as incentives for bioenergy, may contribute to biodiversity decline when they encourage a large-scale conversion of native and semi-natural ecosystems to production fields. In order to appreciate the impact of these incentives on biodiversity, it is imperative to better understand how native and semi-natural ecosystems contribute to plant diversity and composition. We studied the five most common types of managed grasslands in Northeastern Kansas, a region undergoing agricultural intensification. We analyzed plant community data recorded at three spatial scales in 98 managed grassland sites, and examined patterns of diversity and composition of plant species and functional groups; and spatial turnover of species and functional groups measured at different spatial scales. We found reduced soil quality and plant diversity as well as a lack of scale-dependent community patterns on sites that were historically cultivated. Forage management practices (haying or grazing) altered plant diversity and composition in native grassland remnants but not in non-native grasslands. We identified several opportunities where changes to existing management practices could benefit both conservation and bioenergy production objectives. Recommendations to conserve biodiversity include increasing the use of hay management or other biomass collection on native grassland remnants and improving the Conservation Reserve Program by increasing enrollment, adding more native species to seed mixes, and incorporating a periodic biomass collection. We also found that using measures of spatial turnover in community composition added important insights in understanding the effects of management decisions on biodiversity. 相似文献
11.
Biodiversity conservation in human-modified landscapes of Mesoamerica: Past, present and future 总被引：1，自引：0，他引：1
Fabrice A.J. DeClerck Robin Chazdon Jeffrey C. Milder Alejandra Martinez-Salinas 《Biological conservation》2010,143(10):2301-2313
Mesoamerica provides a unique context for biodiversity conservation in managed landscapes because of its geography, history of human intervention, and present conservation and development initiatives. The long and narrow form of the Mesoamerican landmass, and its division by a central mountain range, has served as both a bridge and a barrier. Conservation efforts in Mesoamerica are unique for the emphasis they place on regional connectivity through the Mesoamerican Biological Corridor and on biodiversity conservation in managed landscapes. The emphasis on conservation in agricultural systems has fostered innovations in payment for ecosystem services, and provides novel insights on the functional role that biodiversity plays in the provisioning of ecosystem services. The increasing rate of economic development in the region and the advent of new payment for ecosystem service schemes have provided new opportunities for forest regeneration and restoration. However, the small scale of private landholdings and the diversity of land uses featured in the region, while contributing to biodiversity conservation due to their structural and floristic complexity, present challenges for biodiversity monitoring and management. 相似文献
12.
土壤在植物多样性形成中的作用及其研究意义 总被引：2，自引：0，他引：2
土壤科学工作者熟知生物作为五大成土因素之一在土壤发生与演化过程中的作用,但是很少问津土壤在植物起源和演化过程的作用.笔者认为,陆地植物的起源和演化过程实质上是对其起源土壤环境的适应过程,土壤对起源植物特性的形成具有"模具效应".土壤环境的剖面厚度和层次构型、物理、化学和生物学性质多样性形成了起源植物的多样性.由于植物根... 相似文献
13.
胞外DNA在土壤中的固定与转化 总被引：3，自引：0，他引：3
DNA is the genetic material of various organisms. Extracellular DNA adsorbed or bound on surface-active particles in soils has been shown to persist for long periods against nucleases degradation and still retain the ability to transform competent cells. This paper reviews some recent advances on the binding and transformation of extracellular DNA in soils,which is fundamental to understanding the nature of the soil, regulating biodiversity, and assessing the risk of releasing genetically engineered microorganisms (GEMs) as well as being helpful for development of the genetic evolutional theory of bacteria. Several influencing factors, such as soil pH, ionic strength, soil surface properties, and characteristics of the DNA polymer, are discussed. To date, the understanding of the type of molecular binding sites and the conformation of adsorbed and bound DNA to soil particles is still in its infancy. 相似文献
14.
中国渤海海岸盐碱土及非盐碱土中土壤生物多样性 总被引：1，自引：0，他引：1
A plethora of information is available on the effects of salinity on plant growth and soil physico-chemical properties,but the effects on soil organisms are often neglected.Thus,a systematic investigation of how soil biodiversity,including bacteria,nematodes,mites,and earthworms,changes along saline gradients was conducted along the Bohai Sea coast at Laizhou City,Shandong Province,China,with 30 soil samples randomly selected and classified by salinity into two categories:saline and non-saline.Testing revealed a significantly higher abundance of the surveyed organisms in non-saline soils.The redundancy analysis showed that a negative correlation was observed between electrical conductivity and soil organism abundance in saline soil,but not in non-saline soil.Soil organic matter,available nitrogen,and total nitrogen all positively affected organism abundance in both saline and non-saline soils.The richness and Shannon diversity of nematodes were significantly higher in non-saline soils,but were not significantly different between soil types for other organisms.None of the environmental factors surveyed was obviously related to soil organism diversity.Consequently,our results suggested that soil electrical conductivity only negatively affected soil organisms in saline soil,while soil fertility positively affected soil organisms in both saline and non-saline soils. 相似文献
15.
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
16.
A major problem facing ecologists is obtaining a complete picture of the highly complex soil community. While DNA-based methods are routinely used to assess prokaryote community structure and diversity in soil, approaches for measuring the total faunal community are not yet available. This is due to difficulties such as designing primers specific to a range of soil animals while excluding other eukaryotes. Instead, scientists use laborious and specialized taxonomic methods for extracting and identifying soil fauna. We examined this problem using DNA sequencing to profile soil animal diversity across two Alaskan ecosystems and compare the results with morphological analyses. Of 5267 sequences, representing 549 operational taxonomic units (OTU), only 18 OTUs were common to both sites. Representatives included 8 phyla, dominated by arthropods and nematodes. This is the most comprehensive molecular analysis of soil fauna to date, and provides a tool to rapidly assess a missing component of soil biodiversity. 相似文献
17.
Conversion of arable land into semi-natural grassland or heath land is a common practice for restoring and conserving plant diversity. However, little is known about the effectiveness of land conversion for restoring and conserving taxonomic and functional diversity in the soil. We studied soil nematode community development in a chronosequence of abandoned fields and related this to plant community development. The taxonomic and functional composition of the soil nematode community was analyzed to detect changes in soil food web structure, using semi-natural sites and theoretical plant and soil communities as references.While plant communities clearly developed towards the semi-natural references, there was less direction in succession of nematode taxa. The number of fungal feeding nematodes increased after land abandonment. Numbers of omni-carnivorous nematodes expanded only during the first years, after which there were no substantial changes for the next three decades. Plant communities on the ex-arable fields developed towards the theoretical reference plant associations Galio hercynici-Festucetum ovinae and Genisto anglicae-Callunetum. Nematode communities developed away from a theoretical community indicative of arable land, but there was no clear development towards a theoretical (semi-)natural reference. Our results show that restoration and conservation of plant communities is of limited indicative value for developments belowground: successful restoration of plant diversity does not necessarily imply successful restoration of belowground diversity. Assessing the impact of conservation measures on restoring soil biodiversity requires information on belowground community composition of (semi-)natural areas in order to establish proper references for restoration sites. 相似文献
18.
作为地球上生物最为丰富的生境,土壤生态系统具有高度的生物多样性,并与地上生态系统有着密切联系。随着经济快速发展,人为干扰日益严重,土壤生物多样性遭受严重威胁,在物种大量灭绝及对土壤生物多样性总体认识相对局限的双重背景下,有效保护土壤生物多样性迫在眉睫。首先,提出了土壤生物多样性的威胁框架,并详述了土地利用变化、农业管理措施、土壤退化、转基因作物、外来植物入侵五大威胁因素在生态系统,物种,基因三个尺度下的不同作用过程。其次,阐明了各威胁因素对土壤生物多样性的具体影响及其驱动机制。最后指出,尽管人们对于上述威胁因素的研究已经有了部分成果,但对于研究各威胁因素在不同尺度下的影响,明确因素间相互作用方式及贡献程度,进行土壤生物多样性威胁的空间精细化制图等方面还面临着巨大挑战。分析土壤生物多样性潜在威胁能够为实现对其综合定量评估、保护土壤生物多样性以及城市规划等提供有力依据。 相似文献
19.
《European Journal of Soil Biology》2002,38(3-4):239-244
Two crop production systems, which differ on tillage and pesticides, were compared for biodiversity of soil microarthropod communities. A biodiversity index, which integrates different structure and density parameters (abundance, taxonomic richness, taxonomic diversity, coenotic diversity) was used. Results showed a greater biodiversity in minimum tillage systems compared to deep tillage systems. Pesticides seemed to be only a second order factor of variance on microarthropod biodiversity. 相似文献
