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皖南低丘茶园土壤动物群落结构研究 总被引：13，自引：0，他引：13
本文是1986年10月—1988年10月对皖南低丘茶园土壤动物群落结构调查和研究的结果。调查期间共获大、中、小型土壤动物9468个,分别隶属于6门13纲37类。其中线虫类、螨类和蚁类为优势类群;线蚓类、弹尾类、鞘翅类幼虫、双翅类幼虫、蜘蛛类为常见类群,两者共占全捕量的94.03％。中小型土壤动物平均密度为1—2万个/m~2,大型土壤动物密度为200—500个/m~2。30年树龄茶园土壤动物群落的组成和数量最丰富,多样性、均匀性和密度-类群指数最高,其变化规律一般是30年茶园>20年茶园>15年茶园;7年树龄茶园群落土壤动物个体数虽少,但组成并不贫乏,且分布均匀,故多样性与密度-类群指数较高。土壤结构较好的黄红壤茶园各项指数大于土层薄、排水不良的黄棕壤茶园。群落各项指数秋季均大于春季。 相似文献
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长白山地不同次生林土壤动物群落多样性特征及其分布格局 总被引：1，自引：0，他引：1
《山地学报》2017,(4)
为探讨长白山地不同地貌类型次生林土壤动物群落多样性特征及其分布格局,分别于2015年春季(5月)、夏季(7月)及秋季(9月)对长白山地三种不同地貌类型(玄武岩台地、花岗岩低山和花岗岩丘陵)的次生林土壤动物进行调查研究。研究表明:大型土壤动物类群数季节变化不显著,中小型土壤动物密度季节波动较大。其中,花岗岩低山次生林大型土壤动物密度和类群数均为最低,玄武岩台地次生林中小型土壤动物密度和类群数要显著高于其他两个生境。通过比较三种生境土壤动物多样性指数发现,大型土壤动物多样性指数随着季节变化表现出相同的动态趋势,均无显著性差异,而中小型土壤动物多样性指数季节波动呈显著升高或降低趋势,且同一季节玄武岩台地次生林的中小型土壤动物多样性指数要显著高于其他两个生境。对三种地貌类型次生林的土壤动物群落与环境因子间相关关系进行了RDA分析,结果表明土壤动物对土壤有机质、全效养分(N、P)和速效养分(N、P、K)响应程度较高,其中中小型土壤动物优势类群甲螨亚目分布对土壤温度、湿度呈显著正向响应。研究可为次生林的管理及生态恢复提供土壤动物学依据。 相似文献
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黑河中游绿洲化过程中不同开垦年限农田大型土壤动物群落特征 总被引：3，自引：0，他引：3
对不同开垦年限绿洲农田大型土壤动物群落结构特征进行研究,探讨绿洲化过程中农田大型土壤动物群落对土壤环境演变的响应及适应机制。天然荒漠草地开垦为绿洲农田后,新垦绿洲农田大型土壤动物密度和类群丰富度增加为天然荒漠草地的1.95倍和1.54倍,百年绿洲农田土壤动物密度和类群丰富度增加为天然荒漠草地的3.54倍和3.00倍;但群落多样性和均匀度指数变化较小。不同动物类群随着绿洲农田开垦年限增加,其变化规律也存在较大差异,如地蜈蚣科(Geophilidae)、线蚓科(Enchytraeidae)、正蚓科(Lumbricidae)和蝇科幼虫(Muscidae)个体密度逐渐增加,拟步甲科(Tenebrionidae)和象甲科(Curculionidae)个体密度显著降低,而平腹蛛科(Gnaphosidae)、夜蛾科(Noctuidae)幼虫和蚁科(Formicidae)受农田开垦以及开垦年限的影响较小。RDA分析结果表明绿洲化过程中不同开垦年限绿洲农田的土壤温度、pH、土壤粘粉粒、土壤含水量、土壤有机碳和全氮的变化是导致绿洲化过程中绿洲农田大型土壤动物群落演变的主要影响因素,而随着绿洲农田开垦年限增加,土壤含盐量、土壤粗砂粒和细砂粒的变化是导致不同开垦年限绿洲农田大型土壤动物群落演变的主要影响因素。 相似文献
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小兴安岭森林落叶分解与土壤动物的作用 总被引：17，自引：5，他引：17
在小兴安岭地区对 12种落叶分解过程和土壤动物作用进行了研究。采用不同网孔分解样袋 ,排出不同类别土壤动物作用的方法。结果表明 ,落叶分解消耗率 :大孔 >小孔 >对照 ,即大型、中小型土壤动物和微生物的共同作用 >中小型土壤动物和微生物的共同作用 >只微生物的作用。三年平均分解消耗率分别是 2 8.9% (大孔 )、 2 8.2 % (小孔 )和 2 6.2 % (对照 ) ,到第三年末 ,三种样袋 12种落叶平均分解程度分别达到 86.7% (大孔 )、 84 .6% (小孔 )和 78.7% (对照 )。分解初期土壤动物的作用逐渐增大 ,到第二年 10月土壤动物的作用达到了最大值 ,随后土壤动物的作用逐渐降低 ,大型土壤动物的作用小于中小型土壤动物的作用。落叶种类不同 ,分解时间不同 ,土壤动物作用也不同。 相似文献
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公路运营对农田和防护林中小型土壤动物多样性的影响 总被引：1，自引：1，他引：0
对距高速公路不同距离样点中小型土壤动物多样性、相似性进行统计及典范对应分析（CCA）。共捕获中小型土壤动物9 994只,隶属3纲6目15科。研究发现：① 高速公路旁林地中小型土壤动物个体数高于农田;林地和农田中小型土壤动物多样性在样点和季节间存在显著差异（P<0.05）。② 林地距离高速公路5 m和1 600 m样点、农田距离高速公路5 m和800 m中小型土壤动物群落相似性较低。③ 土壤有机质含量是影响高速公路林地和农田中小型土壤动物群落分布的重要土壤环境因子。距离高速公路远的林地和农田样点（800 m和1 600 m）中小型土壤动物多样性高于近距离样点（5 m）中小型土壤动物多样性,与公路的运营对周边地区土壤理化性质、地表植被等的影响有关。 相似文献
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科尔沁沙地夏秋(6—9月)季不同类型沙丘土壤呼吸对气温变化的响应 总被引：6，自引：3，他引：3
通过测定分析了科尔沁沙地6—9月不同生境（固定、半固定和流动沙丘）土壤呼吸速率的日动态、月际动态及其对气温变化的响应。结果表明：测定期平均土壤呼吸速率在各生境间存在显著差异,其大小为固定沙丘（2.35 μmolCO2·m-2·s-1）＞半固定沙丘（1.67 μmolCO2·m-2·s-1）＞流动沙丘（1.06 μmolCO2·m-2·s-1）;指数模型能够较好地揭示不同生境土壤呼吸对气温变化的响应,但土壤呼吸的月际动态与气温变化不完全同步;各生境土壤在高温环境下的Q10值(土壤呼吸对温度敏感程度)普遍低于低温环境下的Q10值;固定、半固定和流动沙丘基于气温月际变化的Q10值分别为2.34、1.99和1.31,表明不同的植被状况和土壤性质会影响到土壤呼吸对温度变化的敏感程度。 相似文献
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农牧交错带不同土地类型土壤动物生态特征研究——以内蒙古卓资山为例 总被引：3，自引：0，他引：3
对内蒙古中部农牧交错带不同土地类型土壤动物进行研究,发现线虫占绝对优势,个体数占总个体数的64.95%.线虫个体数在不同土地类型的差异显著.线虫、蜱螨类和弹尾类构成研究区中小型土壤动物的优势类群.天然草地各生境土壤动物的类群数和个体数均高于撂荒地、半裸露坡地和裸露坡地.大型和中小型土壤动物的类群数和个体数的垂直分布具有表聚性.根据土壤动物聚类分析的结果,可将采样的6个生境分为3类:天然草地、人类干扰停止后自然恢复的坡地和裸露坡地.CCA排序表明土壤含水量对中小型土壤动物类群分布影响最大.土地利用方式相近的生境,土壤动物种类组成和个体数量相似程度较高.土壤动物组成的差异能够较好地反映土地类型的差异. 相似文献
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大兴安岭北部森林生态系统 大型土壤动物群落特征 总被引：9，自引：0，他引：9
对大兴安岭北部7个代表性森林群落进行了系统调查,总共获取大型土壤动物67类、6729只,隶属于4门7纲18目51科。其中,优势类群1类,常见类群10类,稀有类群56类。寒温带森林土壤动物生物量最大的类群为线蚓和蚯蚓,而温带森林土壤动物生物量最大的类群以蚯蚓为主。不同群落土壤动物的种类组成差异很大,通常群落的生境条件越优越,土壤动物的个体数量、种类越多。不同群落间个体数量、种类及生物量三者总的分布规律不完全一致,表现出生物群落组成特征的复杂性。各群落土壤动物多样性指数排序为:Ⅰ＞Ⅳ＞Ⅶ＞Ⅴ＞Ⅱ＞Ⅲ＞Ⅵ。土壤动物的个体数量、种类、生物量及多样性指数具有较明显的季节变化。 相似文献
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《Singapore journal of tropical geography》2018,39(2):281-299
This paper examines spatial and temporal patterns of large to medium‐sized fires across the Indonesian Archipelago using remote sensing, particularly the MODIS fire products, over a 14 years period (2000–13 inclusive) in conjunction with climatic and land data in a GIS. Results showed fires (burned area and number of fires) were detected the most in year 2002 and least in 2010. The extent of burning was correlated with the annual Southern Oscillation Index with most burning occurring during times of sustained negative SOI values, which generally means drier conditions across the region. Most of the detected fires occurred in the middle of the dry season and in drier eastern Indonesia. Across Indonesia, approximately 1.5 per cent of available open vegetation area burned, whereas only 0.5 per cent of forest area burned. Most open vegetation burning was detected in the savanna with an area equivalent to 11.1 per cent of its extent being burned over the 14 years. On Sumba Island, where the pronounced dry season extends for at least four months, open vegetation is the most common land cover type, of which 99 per cent burned by area over the study period making it the island with the most burned areas in the Indonesian Archipelago. 相似文献
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芜湖市郊土壤动物与土壤环境 总被引：1，自引：0，他引：1
作者在芜湖市郊七种主要土壤类型中进行了土壤动物调查,共获大、中小型土壤动物3604个,隶属于5门12纲26目32类。其中线虫类、螨类、弹尾类为优势类群;线蚓类、蚁类、蚯蚓类、鞘翅目幼虫为常见类群。结果表明:土壤动物的群落结构与土壤环境有密切关系;自然土壤中土壤动物的数量明显高于耕作土壤;土壤动物的丰富度与土壤有机质含量呈正相关:类群数与个体数随土壤深度的增加而递减。 相似文献
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《自然地理学》2013,34(5):407-422
High-intensity forest fires can degrade, collapse, or completely destroy clay minerals in soils, with signatures of these changes remaining for years after the burns. To ascertain immediate impacts of high-intensity fire on soil clay minerals and mineral recovery over time, soil from the 2002 Hayman, Colorado, fire was analyzed by X-ray diffraction. Sample locations included burned soil from within the perimeter of the fire, unburned soil near the origin, and soil from adjacent historic burns. The unburned soils contain mixtures of illite, mixed-layer illite/smectite and illite/vermiculite, kaolin, and mixed-layer chlorite. Surface soils (surface-7.7 cm) contain illite, mixed-layer illite/smectite, and kaolin. Sub-surface soils (7.7-13.0 cm) contain mixed-layer illite/vermiculite, in addition to the same minerals found at the surface. Deep soils (13.0-27.0 cm) show disappearance of mixed-layer illite/smectite and illite/vermiculite and show evidence of the presence of mixed-layer chlorite. Comparisons between recently and historically burned soils and unburned soils showed slight trends in alterations of clay mineral structures in the surface soil, including alteration of the 001 illite peak, the 001 kaolin peak, and a decrease in the swelling component of mixed-layer illite/smectite. These trends indicate fire impacts the structure of soil clay minerals. 相似文献
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Fire in shrub-dominated portions of the Great Basin, largely fueled by non-native annuals such as Bromus tectorum, has become an important structuring force altering vegetation composition and soil characteristics. The extent to which fire affects native species in drier portions of the Great Basin, termed salt desert, is poorly documented. We conducted a survey of grazed salt desert habitat in northwestern Nevada 5 years after wildfires burned 650,000 ha, with the goal of investigating community response to fire and factors correlating with post-fire recovery. We found that recruitment of a dominant shrub, Artemisia spinescens, is severely restricted following fire: it occurred in only 2 of the 24 burned sites. The co-dominant shrub, Atriplex confertifolia, occurred in most burned sites although on average its percent cover was one-third lower than adjacent unburned sites. Biotic soil crust cover was four times lower, and non-native species cover 5 times higher, in burned sites compared to unburned. Ordination analyses confirmed differences among plant communities in burned versus unburned sites, with environmental variables soil conductivity, plant litter, soil potassium (K+) and pH explaining 38% of the variance in community composition. However, we found no environmental predictors of recovery for native species in burned sites. Future recruitment is likely to be further limited, as fire frequency in the salt desert is expected to increase with invasion by non-native annual grasses and with global climate change. 相似文献
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In the Mediterranean area, forest fires have become a first-order environmental problem. Increased fire frequency progressively reduces ecosystem recovery periods. The fire season, usually followed by torrential rains in autumn, intensifies erosion processes and increases desertification risk. In this work, the effect of repeated experimental fires on soil response to water erosion is studied in the Permanent Field Station of La Concordia, Valencia, Spain. In nine 80 m2 plots (20 m long × 4 m wide), all runoff and sediment produced were measured after each rainfall event. In 1995, two fire treatments with the addition of different biomass amounts were applied. Three plots were burned with high fire intensity, three with moderate intensity, and three were unburned to be used as control. In 2003, the plots with the fire treatments were burned again with low fire intensities. During the 8-year interval between fires, plots remained undisturbed, allowing regeneration of the vegetation–soil system. Results obtained during the first 5 months after both fire experiments show the high vulnerability of the soil to erosion after a repeated fire. For the burned plots, runoff rates increased three times more than those of 1995, and soil losses increased almost twice. The highest sediment yield (514 g m− 2) was measured in 2003, in the plots of the moderate fire intensity treatment, which yielded only 231 g m− 2 of sediment during the corresponding period in 1995. Runoff yield from the control plots did not show significant temporal changes, while soil losses decreased from 5 g m− 2 in the first post-fire period to 0.7 g m− 2 in the second one. 相似文献
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陕北黄土高原人工林下土壤干化原因与防治 总被引：39，自引：13，他引：26
黄土高原的退耕还林是一项史无前例的宏伟工程,成功实施该项工程对恢复该区严重恶化了的生态环境和减少黄河下游水患具重大现实意义。当前植树造林面临的需要解决的重要问题是土壤干化。土壤干化导致人工林生长不良,甚至干枯死亡,查明土壤干化原因对在植树造林工作中采取合理对策有重要作用。野外调查和资料分析显示,陕北黄土高原土壤干化原因有两个方面:一是自然原因;二是人为原因。自然原因包括该区本来降水量较少,近50 a来降水减少和气温升高3个方面。人为原因包括植被破坏,人工林密度过大,在不适于森林发育的地带进行了造林和没有遵循植被演替规律进行了造林4个方面。根据黄土高原已经发生了变化的自然条件,本文建议在陕西延安以南至关中盆地南缘的落叶阔叶林带应采取植被的自然恢复或人工草灌和稀疏的植树相结合的措施恢复森林植被,在延安至长城之间的森林草原带应以人工发展优良草灌为主,配合大间距的植树恢复森林草原植被,在长城以北以种草为主。为提高乔木成活率和确保人工林正常生长,继续采取建造鱼鳞坑等集雨工程措施是很必要的。 相似文献
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Influences of forest roads on the spatial patterns of human- and lightning-caused wildfire ignitions 总被引：1，自引：0，他引：1
Ganapathy Narayanaraj Michael C. Wimberly 《Applied geography (Sevenoaks, England)》2012,32(2):878-888
Understanding the spatial patterns of fire ignitions and fire sizes is essential for understanding fire regimes. Although previous studies have documented associations of human-caused fire ignitions with road corridors, less consideration has been given to understanding the multiple influences of roads on the fire regime at a broader landscape-scale. Therefore, we examined the difference between lightning- and human-caused fire ignitions in relation to forest road corridors and other anthropogenic and biophysical factors in the eastern Cascade Mountains of Washington State. We used geographical information systems and case-control logistic regression models to assess the relative importance of these explanatory variables that influence the locations of lightning versus human-caused ignitions.We found that human-caused ignitions were concentrated close to roads, in high road density areas, and near the wildland-urban interface (WUI). In contrast, lightning-caused ignitions were concentrated in low road density areas, away from WUI, and in low population density areas. Lightning-caused ignitions were also associated with fuels and climatic and topographic factors. A weak but significant relationship between lightning-caused fire and proximity to gravel roads may be related to fuels near roads or to bias in detection and reporting of lightning-caused fires near roads. Although most small fires occurred in roaded areas, they accounted for only a small proportion of the total burned area. In contrast, the large fires in roadless and wilderness areas accounted for most of the burned area. Thus, from the standpoint of the total area burned, the effect of forest roads on restricting fire size is likely greater than the impact of roads on increasing fire ignitions. The results of our study suggest that roads and their edge effect area should be more widely acknowledged as a unique type of landscape effect in fire research and management. 相似文献