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1.
以乌拉特荒漠为研究区,通过10 km×10 km网格均匀布设点位,采用样方法对自然植被展开调查并对研究区土壤特征进行分析。结果表明:(1)研究区共137种植物,隶属于25科80属;生活型以草本为主,占总植物种数的67.88%;水分生态类型以旱生植物为主,占总数的76.64%。(2)依据《中国植被》将乌拉特荒漠植被类型划分为3个植被亚型、5个群系组、14个群系,主要以珍珠猪毛菜荒漠群系占优势,其含样点数占全部荒漠样点数的16.35%。(3)植被物种组成相对单一,分布范围为5~25种。(4)物种多样性指数与土壤养分存在不同程度的相关性,均匀度指数与土壤容重、含水率、孔隙度等均呈负相关关系,丰富度指数、多样性指数与土壤容重及全氮、全磷、有机质含量均呈负相关关系,土壤含水率为该区植物丰富度指数的决定性因子。  相似文献   

2.
为了解土壤影响湿地植物多样性的主要因子,在广佛地区9大湿地类型选取18个样地作为研究对象,通过样方调查以及内业试验获得湿地群落物种组成分布、植物多样性、土壤状况等数据,运用方差分析、典范冗余分析(RDA)、典范对应分析(CCA)对群落分布、植物多样性与土壤因子之间的相关性进行分析。经实地调查,统计出湿地植物312种,隶属90科198属,以禾本科(Gramineae)、莎草科(Cyperaceae)、菊科(Compositae)等为优势科。草本植物占绝对优势,占79.17%。主成分评价结果表明, 近海及海岸湿地土壤养分水平较高。RDA排序分析结果表明土壤因子对植物多样性影响较大的指标是土壤有机质、全氮、全磷、全钾、碱解氮;CCA排序结果表明土壤环境因子对湿地草本植物群落分布主要影响因子为pH、速效钾、有效磷。各研究结果表明,湿地生态系统比陆地生态系统更为复杂和脆弱,植物群落与土壤环境因子之间的关系也更为复杂,湿地植被的分布格局、群落多样性、群落结构和土壤条件及其相互关系受到人为干扰的类型和强度影响更加明显。  相似文献   

3.
Soil microorganisms are applied to evaluate soil quality and significant in restoration ecology for their important roles on nutrient cycle and sensitivity to environment changes. To investigate the effects of re vegetation pattern on soil physicochemical properties and soil bacterial community and the reasons for soil bacterial community discrepancy, the soils of three re vegetation patterns (grass of Miscanthus sinensis, the mixed forest of Alnus nepalensis, Cupressus torulosa and Quercus acutissima, the mixed forest of Cupressus torulosa and Alnus nepalensis) in Kunyang phosphate mine, near Kunming, Yunnan province of China were studied. Polymerase chain reaction denaturing gradient gel electrophoresis (PCR DGGE) and soil physicochemical indices were used to analyze soil bacterial communities (diversity and species composition) and soil physicochemical properties. The results indicated that re vegetation contributed to soil nutrients and soil physicochemical properties were different in these three patterns. As for soil bacterial community, the diversity and species composition varied in different patterns. Pearson correlation showed that soil bacterial community diversity was correlated with re vegetation pattern significantly but not with any soil physicochemical properties determined in this research. Soil bacterial species composition was strongly correlated with soil available nitrogen and re vegetation pattern but no others through Canonical Correspondence Analysis (CCA). It is concluded that both soil physicochemical properties and bacterial community (diversity and species composition) vary in different re vegetation patterns and the reason for diversity difference is re vegetation pattern while the affecting factors of soil bacterial community composition are soil available nitrogen and re vegetation pattern orderly.  相似文献   

4.
Studies of grasslands on specific soil types suggest that different nutrients can limit biomass production and, hence, species composition and number. The Brazilian cerrado is the major savanna region in America and once covered about 2 million km(2), mainly in the Brazilian Central Plateau, under seasonal climate, with wet summer and dry winter. In view of the importance of soil chemical factors in the distribution of the vegetation forms within the Cerrado domain and which may influence the number of species, we analyzed some soil characteristics in three herbaceous vegetation forms -- hyperseasonal cerrado, seasonal cerrado, and wet grassland -- in Emas National Park, a core cerrado site, to investigate the relationship between number of species and soil characteristics. We collected vegetation and soil samples in these three vegetation forms and submitted the obtained data to multiple linear regression. We found out that aluminum and pH were the best predictors of species density, the former positively related to species density and the latter negatively related. Since the predictable variation in species density is important in determining areas of conservation, we can postulate that these two soil factors are indicators of high species density areas in tropical grasslands, which could be used in selecting priority sites for conservation.  相似文献   

5.
The large number of abandoned quarries in many countries presents challenges for restoration of these extremely degraded habitats. To understand soil and plant development in these extreme habitats at a most critical stage of restoration, we evaluated the edaphic conditions and natural vegetation of three large quarries in southern China 3, 5, and 7 years following abandonment. Although soil fertility (organic matter, and N, P, K concentrations) did not differ significantly over a few years, it was much higher than would be expected from newly weathered soil and was comparable to that of the adjacent garden soil on level ground with no slope. This suggests that soil formation on the steep slopes of quarry cliffs is a secondary migration process rather than a primary weathering process. Vegetation cover increased from 10.6 to 18.6 and 23.4%, and species abundance increased from 8 to 11 and 12 species, and from 3 to 6 and 7 families. Plant species composition changed from predominantly annual and perennial herbaceous species to a more diverse community with drought-tolerant and heliophilous shrubs. The vegetation cover was highly positively correlated with soil depth and soil volume ( p < 0.001), and also significantly correlated with soil organic matter, total N, and available N and P concentrations ( p < 0.05). This suggests that vegetation succession is more limited by available soil volume than by soil fertility during the early stages of quarry restoration.  相似文献   

6.
The floristic composition and species diversity of the germinable soil seed bank were studied in three different habitats (desert salinized land, desert wadi, and reclaimed land) in the Eastern Desert of Egypt. Moreover, the degree of similarity between the seed bank and the above-ground vegetation was determined. The seed bank was studied in 40 stands representing the three habitats. Ten soil samples (each 25 × 20 cm and 5 cm depth) were randomly taken per stand. The seed bank was investigated by the seedling emergence method. Some 61 species belonging to 21 families and 54 genera were identified in the germinable seed bank. The recorded species include 43 annuals and 18 perennials. Ordination of stands by Detrended Correspondence Analysis (DCA) indicates that the stands of the three habitats are markedly distinguishable and show a clear pattern of segregation on the ordination planes. This indicates variations in the species composition among habitats. The results also demonstrate significant associations between the floristic composition of the seed bank and edaphic factors such as CaCO3, electrical conductivity, organic carbon and soil texture. The reclaimed land has the highest values of species richness, Shannon-index of diversity and the density of the germinable seed bank followed by the habitats of desert wadi and desert salinized land. Motyka’s similarity index between the seed bank and the above-ground vegetation is significantly higher in reclaimed land (75.1%) compared to desert wadi (38.4%) and desert salinized land (36.5%).  相似文献   

7.
L.M. Chu 《应用植被学》2008,11(3):297-306
Question: What is the relationship of the naturally colonizing vegetation and substrate characteristics in fly ash lagoons? Location: West lagoon, Deep Bay, a 13‐ha coastal lagoon in Hong Kong in subtropical Southeast Asia. Methods: Vegetation establishment was examined in a coal fly ash lagoon two years after its abandonment to investigate the distribution of vegetation in relationship to the chemical properties of the fly ash in the lagoon. A greenhouse experiment assessed the limits imposed on plant growth in fly ash. Results: The fly ash was saline, slightly alkaline and very poor in organic matter and nitrogen. Ash from bare and vegetated areas differed significantly in their salinity and extractable concentrations of inorganic nitrogen and various metals. Bare ash had a significantly higher conductivity and extractable sodium, aluminum, manganese, potassium, and lead. In total 11 plant species that belonged to seven families were found growing on the fly ash; all species except the shrub Tamarix chinensis were herbaceous. Using discriminant analysis, the most important factors in distinguishing bare and vegetated ashes were conductivity and sodium. Cluster analysis of bare samples gave two distinct groups, one from the periphery of the lagoon, which had lower sodium, conductivity, organic carbon, potassium and copper, and the other from a second group that contained ashes from the central region of the lagoon. Results of the greenhouse experiment showed that the inhibition of plant growth was significantly correlated with the presence of soluble toxic elements in ash. Conclusion: Toxicity and salinity seem to be the major limiting factors to plant establishment in fly ash, and these factors must be ameliorated for the successful reclamation of these fly ash lagoons.  相似文献   

8.
The species composition in the soil seed bank of degraded hillslopes in southern Wello, Ethiopia, was assessed using the seedling emergence method and compared with that of the standing vegetation. Surface soils were sampled at 0‐to 5‐cm depth from 49 plots of four physiognomic vegetation classes (hereafter vegetation classes): forests, shrublands, grasslands, and degraded sites. Soils were spread on sterile sand in a glasshouse and watered. Emerging seedlings were recorded for five months until no new seedlings emerged. A total of 3969 seedlings belonging to 71 species and 30 families germinated. The species composition of the seed bank was dominated by 53 herb species (75%) compared to 2 tree species which accounted for only 3 percent of the total number of species. Seedling density differed significantly among vegetation classes and ranged from 391 to 7807 seeds/m2. Mean species richness also differed significantly among the vegetation classes. Forty‐two species were found to be common to the seed banks and the standing vegetation; however, correspondence between species numbers and composition of the seed banks and the standing vegetation was poor. Although most of the species that germinated in the seed banks were herbs and grasses, they can develop a vegetative cover and contribute to reduction of soil erosion. Regeneration of the tree species (some of which have seed viability up to four years) however, requires both time and the presence of mature individuals. Together with hillside closure and soil conservation measures (e.g., terracing), planting of native woody seedlings might help to expedite rehabilitation of degraded hillslopes devoid of trees and shrubs.  相似文献   

9.

Questions

Dryland annual plant communities constitute the most species-rich small-scale vegetation in the Mediterranean. Nevertheless, the composition and diversity of these units and the factors controlling their variation are still insufficiently understood. Therefore, we investigated species composition and richness patterns in relation to important environmental gradients provided by climate and soil.

Location

Central Crete, Greece.

Methods

The study is based on 82 plots of 4 m2 sampled at altitudes between 11 and 1400 m a.s.l. We conducted vegetation relevés and soil analyses. We used generalised additive models to model species richness and community characteristics along the studied gradients. We then performed distance-based redundancy analysis to determine the main environmental factors influencing species composition. To determine species of diagnostic value for bedrock types, we applied an indicator species analysis. Correlation tests were used to test the performance of the South Aegean Plant Indicator Values on our dataset.

Results

We recorded 347 taxa (species and subspecies) of 43 plant families, and mean species numbers of 47.2 ± 12.5 per plot. While overall species richness varied only slightly along the analysed environmental gradients, significant changes were observed for relative proportions of species from different life forms and families. Soil pH and elevation had the highest influence on the variation in species composition (23.3% explained). We found 22 species indicative of calcareous rock and 24 species indicative of lime-deficient rock types. The South Aegean Plant Indicator Values were relatively strongly correlated with environmental variables.

Conclusions

Results indicate considerable species turnover both along climatic (elevation) and soil gradients, highlighting the special importance of soil pH. The data provided by our study are expected to supply relevant ecological background information for a pending classification of East Mediterranean annual-rich vegetation.  相似文献   

10.
Soil seed banks can exert a strong influence on the path of vegetation succession following fire, with species varying in their capacity to persist in the seed bank over time, leading to changes in seed bank composition and propagules available for post-fire colonisation. This study examined the effect of time since fire on soil seed bank dynamics in a chronosequence of seven sites spanning 26 years in a south-eastern Australian sand heathland. No significant change was evident in the species richness and density of the germinable soil seed bank, but species composition differed significantly among young (0–6 years since fire), intermediate (10–17 years since fire) and old-aged (24–26 years since fire) sites (using presence/absence data). No significant trend was observed in the similarity between the extant vegetation and the soil seed bank with time since fire. A total of 32% of the species recorded in the soil seed bank were not present in the above-ground vegetation at the same site, which suggests that species requiring fire for germination may be present in the seed bank. Most species present in the extant vegetation were not recorded (63%) or were in very low abundances in the soil seed bank (29%). The mode of regeneration appears to be the major determinant of species absence in the soil seed bank, as 66% of species occurring in the extant vegetation but not in the seed bank have the capacity to regenerate by resprouting. This study shows that a major shift in the successional pathway after fire due to altered seed bank composition is unlikely in this vegetation; most species not recorded in the seed bank are either resprouters (obligate or facultative) or serotinous, suggesting that they will readily regenerate following fire. Unless fire frequencies are high and kill fire-sensitive obligate seeders before they reach maturity, the chance that the soil seed bank could substantially alter vegetation composition within the study area after fire is low. However, it is unclear how successional pathways may alter in response to severe fires with the potential to kill both seeders and resprouters.  相似文献   

11.
In the Loess Plateau region, soil erosion is a serious problem. Vegetation restoration is an effective approach to control soil erosion and improve ecosystems. The soil seed bank generally plays an important role in vegetation restoration after disturbance. Thus, we reviewed soil seed bank studies to reveal the soil seed bank characteristics and its role in vegetation restoration in three vegetation types (forest, forest‐steppe, and steppe). We selected 38 seed bank studies and analyzed several seed bank characteristics, such as seed density, species composition, and the relationship between seed size and seed bank. We also assessed the role of the soil seed bank in vegetation restoration. The soil seed bank density ranged from 2,331 ± 1,993 to 6,985 ± 4,047 seeds/m2 among the different vegetation types. In the soil seed bank, perennial herbs and grasses accounted for 51.5% of the total species. Native species that were dominant or common in the standing vegetation usually had relatively high seed bank densities. Moreover, species with smaller seeds generally had higher soil seed bank densities. The present study indicates that the soil seed bank plays a significant role in spontaneous vegetation restoration, especially during the early successional stages in abandoned slope farmlands and grazing‐excluded grasslands. However, species with large seeds or transient soil seed banks should be reintroduced through seeding to accelerate target species restoration. More studies on soil seed banks need to be conducted to comprehensively reveal their characteristics.  相似文献   

12.
矿区不同类型生态护坡工程植物多样性对环境因子的响应   总被引:1,自引:0,他引:1  
以太原市西山矿区岩质边坡、土质边坡、岩土混合边坡3种类型生态护坡工程为对象,采用典范对应分析(CCA)排序研究不同类型边坡环境因子与物种分布的关系,并分析土壤和地形等环境因子对植物多样性的影响.结果表明:岩土混合边坡植被组成较为丰富(8科17属19种),以菊科、禾本科、豆科、葡萄科、唇形科、苦木科为主;物种丰富度指数、...  相似文献   

13.
采用时空替代法,对甘肃省民勤县青土湖不同年限退耕地(退耕1 a、2 a、4 a、8 a、13 a、20 a、30 a、40 a)的植被演替特征、土壤酶活性进行调查,以耕地为对照(CK),分析植被群落与土壤酶活性的相关性,以揭示其变化规律及其驱动机制,为青土湖区及其相似地区退耕地生态系统修复及生态环境建设提供理论基础。结果表明:(1)青土湖在退耕40 a自然恢复过程中,9个样方中共出现16科32属42种植物,物种构成表现为:多数种归于少数科,大部分植物种为单属单科。(2)随着退耕年限的增加,群落优势种由草本植物逐渐转化成灌木植物,植物种由退耕初期(1 a或2 a)的19种降低到退耕4 a的14种、退耕20 a的13种、退耕30 a的5种;退耕30 a时耐盐碱灌木植物盐爪爪成为该地的优势种,其重要值达到52.862,但退耕40 a时优势种盐爪爪的重要值降为36.008。(3)随着退耕年限增加,植物Margalef丰富度指数呈波动式下降的趋势;Shannon多样性指数和Pielou均匀度指数总体趋势呈先增加后减小,再逐渐趋于稳定;Simpson优势度指数整体变化幅度较小,最终呈稳定的趋势。(4)在不同土层(0~20 cm和20~40 cm)中,4种土壤酶活性随退耕年限增加总体表现出先升高后下降再逐渐趋于稳定的趋势,均在退耕8 a后显著下降,且磷酸酶和脲酶活性均显著低于蔗糖酶和过氧化氢酶活性;与对照样地(CK)相比,磷酸酶活性与脲酶活性均随退耕年限增加而下降;土壤磷酸酶、蔗糖酶和脲酶活性均随土层加深而降低。(5)相关分析结果显示,0~20 cm土层中,物种数与土壤蔗糖酶活性、磷酸酶活性以及脲酶活性均呈显著正相关关系;20~40 cm土层中,物种数与土壤脲酶活性呈极显著正相关关系,与土壤过氧化氢酶活性呈显著负相关关系;Margalef丰富度指数与0~20 cm土层的磷酸酶活性和蔗糖酶活性均呈显著正相关关系,与脲酶活性呈极显著正相关关系;20~40 cm土层中,Margalef丰富度指数与脲酶活性呈极显著正相关关系;Shannon多样性指数、Pielou均匀度指数和Simpson优势度与4种土壤酶活性间相关性较低且均不显著。研究认为,在青土湖区退耕地植被自然演替过程中,植物群落变得比较单一,物种多样性逐年降低,脲酶活性对物种多样性起着关键性作用。  相似文献   

14.
Soil pH was measured at two different spatial scales in coastal dunes on Norderney, North Sea, and in Mecklenburg-Vorpommern, Baltic Sea, Germany. Relationships between the variability in soil pH, species richness and species diversity are presented. Species richness and diversity were highest in grey dunes, where soil pH was at intermediate levels; both variables were lower in yellow and brown dunes. The variability in pH increased with increasing species diversity and also with scale. Overall, soil pH variability decreased with increasing vegetation cover. The lowest pH heterogeneity was found in heath dominated by Empetrum nigrum L. and grey dunes dominated by Campylopus introflexus (Hedw.) Brid. Increasing abundance of dominant species and decreasing species diversity of vegetation apparently reduces soil heterogeneity. Decreasing species diversity of vegetation is likely to explain decreasing variability in soil pH.  相似文献   

15.
2004年4—10月,在甘肃子午岭天然次生林区采用巴氏诱罐法采集土壤蜘蛛2164头,隶属于19科43种。研究表明辽东栎林(Quercusliaotungensis)、油松林(Pinustabulaeformis)和杨树林(Populusdavidiana)3种森林植被类型中土壤蜘蛛群落组成有明显的差异;不同生境蜘蛛群落的组成成分和多样性指数各异;从各生境中捕获的蜘蛛个体数量分析,皿蛛科、平腹蛛科和科狼蛛科的数量最多,优势类群的组成相似;各生境类型中蜘蛛功能集团的组成及多样性也有明显差异。同时,分析了影响蜘蛛群落组成和多样性的主要因子是生境的植被类型和生境异质性。  相似文献   

16.
为了探究三江平原沟渠土壤种子库在湿地植物保护中的作用及其在湿地恢复中的潜力,该文采用幼苗萌发法与样方调查相结合的方法,对三江平原不同开挖年限沟渠的土壤种子库特征及其与地上植被的关系进行了研究。结果表明:沟渠具有较大规模的土壤种子库,边坡种子库显著大于底泥种子库,边坡种子库密度为8 973–25 000 seeds·m–2,底泥种子库密度为506–1 488 seeds·m–2。开挖10年、20年和30年的沟渠土壤种子库共有50种植物萌发,隶属于20科41属。开挖10年、20年和30年的沟渠土壤种子库萌发物种数分别为37种、34种和33种,地上植被物种数分别为25种、33种和22种。土壤种子库和相应地上植被的相似性系数分别为38.7%、35.8%和32.7%。随着植物群落演替的进行,地上植被的Simpson指数、Shannon-Wiener多样性指数和Pielou均匀度指数均逐渐增大。三江平原沟渠土壤种子库和地上植被中保存了大量湿地植物,表明沟渠具有保护植物物种多样性的作用,沟渠土壤种子库具有湿地恢复的潜力。随着沟渠开挖年限增加,沟渠植物群落呈现退化特征,建议对沟渠系统加强管理。  相似文献   

17.
铜官山铜尾矿库植被及土壤酶活性研究   总被引:32,自引:8,他引:24  
通过野外调查和实验分析,对铜官山铜尾矿库的植被状况和土壤酶活性进行了研究.结果表明,铜宫山铜尾矿库自然定居的高等植物有34种,隶属于16个科33个属,多为1—2年生草本植物,主要隶属于菊科、禾本科和豆科,蔗类植物节节草在尾矿库中也具有较大优势.尾矿库植被形成了节节草+白茅群落、狗牙根+白茅群落及芦苇群落等小群落,但仍以单种植物组成的斑块零散分布为主.对尾矿库土壤酶活性的研究表明,3种土壤酶活性和尾矿库的植被状况具有较强的相关性,且3种酶活性与其相关性表现为脲酶>蔗糖酶>过氧化氢酶.建议用脲酶活性作为废弃地复垦的一个指示指标。  相似文献   

18.
Although Carabidae is among the best-studied families of beetles in Europe from the faunistic point of view, there is still a lack of available information on the ecological requirements of the particular carabid species. The habitat preferences that determine the distribution of species are largely influenced by habitat structure and microclimate. In addition to other factors, these habitat parameters are influenced by the nature of the vegetation. Therefore, our study investigated the influence of tree species on carabid beetle communities. We conducted the research at 9 stands in the Borová Hora Arboretum (Zvolen, Central Slovakia). Each studied site represents a monoculture of one of nine tree species. At each site, some soil and leaf litter attributes (pH, conductivity, and content of H, C, N and P) were evaluated. Ground beetles were collected by pitfall trapping during the vegetation periods in 2008–2011. In total, 3012 individuals of 29 species were obtained. Significant differences in the total dynamic activity and species richness of the carabid beetle communities among the compared forest stands were revealed. The results of the research confirmed statistically significant relationships among 1) the soil conductivity and both the richness and Shannon diversity of the ground beetle communities, 2) the litter and soil N content and richness, the Shannon diversity and the species composition of the ground beetle communities. The Shannon diversity and richness were negatively related to the soil conductivity and positively related with the N content. Our research showed that dominant tree species indirectly influence diversity and composition of carabid communities via the soil properties.  相似文献   

19.
Plant communities are coupled with abiotic factors, as species diversity and community composition both respond to and influence climate and soil characteristics. Interactions between vegetation and abiotic factors depend on plant functional types (PFT) as different growth forms will have differential responses to and effects on site characteristics. However, despite the importance of different PFT for community assembly and ecosystem functioning, research has mainly focused on vascular plants. Here, we established a set of observational plots in two contrasting habitats in northeastern Siberia in order to assess the relationship between species diversity and community composition with soil variables, as well as the relationship between vegetation cover and species diversity for two PFT (nonvascular and vascular). We found that nonvascular species diversity decreased with soil acidity and moisture and, to a lesser extent, with soil temperature and active layer thickness. In contrast, no such correlation was found for vascular species diversity. Differences in community composition were found mainly along soil acidity and moisture gradients. However, the proportion of variation in composition explained by the measured soil variables was much lower for nonvascular than for vascular species when considering the PFT separately. We also found different relationships between vegetation cover and species diversity according the PFT and habitat. In support of niche differentiation theory, species diversity and community composition were related to edaphic factors. The distinct relationships found for nonvascular and vascular species suggest the importance of considering multiple PFT when assessing species diversity and composition and their interaction with edaphic factors. Synthesis: Identifying vegetation responses to edaphic factors is a first step toward a better understanding of vegetation–soil feedbacks under climate change. Our results suggest that incorporating differential responses of PFT is important for predicting vegetation shifts, primary productivity, and in turn, ecosystem functioning in a changing climate.  相似文献   

20.
采用种子萌发法,研究了河水漫溢对塔里木河下游荒漠河岸林地表植被与土壤种子库的影响.结果表明:塔里木河下游漫溢区地表植被分属8科13属14种,非漫溢区为10科21属26种植物;与非漫溢区相比,漫溢区地表植被中出现了一些浅根系和喜湿的草本植物;漫溢区单位面积物种数、植被盖度、植株密度、物种多样性指数和丰富度指数均比非漫溢区有明显增加.漫溢区土壤种子库中有物种19种,比非漫溢区增加了5种;漫溢区土壤种子库总密度比非漫溢区增加了3.94倍;与非漫溢区相比,漫溢区1年生草本植物种子的比例增加了23.07%,而灌木植物种子比例减少了20.99%;多年生草本的变化则不明显;河水漫溢提高了土壤种子库的生物多样性.漫溢区和非漫溢区土壤种子库与地表植被的共有物种分别为18和9种,土壤种子库与地表植被的相似性系数分别为0.842和 0.667.  相似文献   

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