Knowledge Resource Center for Ecological Environment in Arid Area
| 黑河中游土地覆被变化与管理对地面/土壤动物群落演变的驱动机制 | |
| 其他题名 | Land-cover change and management drive changes in ground/soil fauna communities in the middle reaches of Heihe river basin |
| 刘继亮 | |
| 出版年 | 2012 |
| 学位类型 | 博士 |
| 导师 | 李锋瑞 |
| 学位授予单位 | 中国科学院大学 |
| 中文摘要 | 黑河流域是西北干旱区第二大内陆河流域，也是一个能够全面反映我国内陆干旱区自然生态景观全貌的代表性流域。在黑河流域，上游山区（祁连山）是水资源的形成源区，中游人工绿洲区是水资源的主要消耗区，也是人类活动影响强度最大、人地水矛盾最突出的一个区域。然而，目前尚不清楚土地利用/覆被变化与管理措施引起的地表水文和土壤生态环境的变化究竟会对地面/土壤动物群落演变造成什么样的潜在影响？也不清楚干旱环境下土地覆被变化与管理措施耦合作用对地面/土壤动物群落演变的生态驱动机制，更不清楚地面/土壤动物主要类群对土地覆被变化与管理扰动的响应模式与适应机理。针对上述问题，本研究在黑河中游荒漠绿洲区选择天然草地（对照）及天然草地转变的人工梭梭灌木林（21a）、人工杨树林（28a）、人工樟子松林（33a）和农田（开垦27a和100a）6种代表性土地利用/覆被类型为研究对象，于2008～2010年间，系统调查了6种研究样地的地面/土壤动物群落组成和数量特征，定位观测了6种研究样地的植被与土壤生态环境特征，并详细调查了6种研究样地近20年来土地管理措施的使用及其变化情况。利用获得的多变量数据库，综合采用方差分析、多变量分析（DCA、RDA、CCA、NMDS和TWINSPAN）、多元回归和通径分析等统计方法，系统开展了黑河中游不同生态景观单元地面/土壤动物群落区系及其分布特征、土地覆被变化与管理对地面/土壤动物群落演变的耦合影响及驱动机制、地面/土壤动物群落主要类群对人为活动引起的荒漠绿洲生态环境变化的指示作用等方面的研究。主要结果如下：\n（1）荒漠、绿洲和过渡区的地面/土壤动物区系和群落分布特征存在显著差异。荒漠区的地面节肢动物群落数量和物种丰富度高于绿洲区和过渡区，而绿洲区和过渡区的土壤动物群落数量和物种丰富度高于荒漠区。荒漠区地面节肢动物群落的优势类群是拟步甲科（63%）和蚁科（24%），土壤动物群落的优势类群是罗甲螨科（37%）、节跳科（19%）和厉螨科（8%）；过渡区地面节肢动物群落的优势类群是蚁科（35%）和狼蛛科（16%），土壤动物群落的优势类群是罗甲螨科（26%）、节跳科（12%）和奥甲螨科（11%）；绿洲区地面节肢动物群落的优势类群是蚁科（28%）、步甲科（28%）和狼蛛科（14%），土壤动物群落的优势类群是节跳科（41%）、长角跳科（9%）和厉螨科（7%）。\n（2）揭示了土地覆被变化与管理措施对地面节肢动物和土壤动物群落结构和多样性变化的生态调控机制。将天然草地转变为未实施任何管理措施的人工梭梭灌木林后，地面/土壤动物群落数量、类群丰富度和多样性并未发生显著变化，而转变为实施管理措施的杨树和樟子松人工林及农田后，导致了地面/土壤动物群落数量、类群丰富度和多样性的显著变化。这表明，在缺乏管理措施（如灌溉）的情况下，单纯改变土地覆被对地面/土壤动物群落结构的影响较小，而在管理措施存在的情况下，改变土地覆被对地面/土壤动物群落结构产生了显著影响，从而证实了土地覆被变化对地面/土壤动物群落的作用及其效应受管理措施的强烈调控。\n（3）多变量分析表明，灌溉、施肥和土地覆被变化（以植被盖度来表征）对地面/土壤动物群落组成变化均有显著影响，说明地面/土壤动物群落的演变过程受灌溉、施肥和土地覆被变化的共同影响。然而，灌溉、施肥和植被盖度在驱动地面/土壤动物群落演变过程中的作用和贡献率明显不同，灌溉对地面/土壤动物群落变化的贡献率要显著大于施肥和植被盖度，表明灌溉管理是干旱荒漠绿洲生态系统地面/土壤动物群落演变最重要的驱动力。\n（4）通径分析表明，灌溉、施肥和植被盖度对地面节肢动物群落个体数量有显著的直接影响，同时灌溉、施肥和植被盖度通过相互作用对地面节肢动物群落个体数量产生显著的间接作用。从总影响效应看，灌溉对地面节肢动物个体数量的影响最大，植被盖度次之，施肥的影响最小。研究还表明，灌溉对土壤动物群落密度和类群丰富度有显著的直接作用，而施肥和植被盖度主要通过与灌溉的相互作用间接影响土壤动物群落密度和类群丰富度。从总影响效应看，灌溉对土壤动物群落密度和类群丰富度的影响最大，其次是施肥，植被盖度的影响最小。\n（5）偏CCA排序结果表明，影响地面节肢动物群落分布的关键环境因子是土壤有机碳（贡献率为53%）、凋落物量（29%）、pH（9%）、土壤含水量（9%）和土壤质地（7%），而影响土壤动物群落分布的关键环境因子是土壤有机碳（44%）、凋落物量（22%）、土壤含水量（9%）、pH（5%）、土壤温度（4%）和土壤微生物量碳（4%）。\n（6）实施管理的人工林和农田生态系统的土壤动物密度、类群丰富度和多样性均显著高于未实施管理的人工梭梭灌木林，表明人工林和农田生态系统具有较高的土壤动物多样性保育功能。因此，在人工绿洲边缘建立不同类型的人工植被斑块，增加生境多样性，是保护和维持干旱荒漠绿洲土壤动物多样性的有效途径。\n（7）天然草地、人工梭梭灌木林、人工杨树林、人工樟子松林、新垦农田和百年农田6种研究样地土壤节肢动物群落的BSQ（Biological Soil Quality）指数分别为67.2、53.1、117.7、89.7、142.4和180.3，该指数值与土壤含水量、全氮和微生物量碳含量等呈显著正相关，与土壤温度、土壤砂粒和可溶性盐含量呈显著负相关，因而对土地覆被变化与管理引起的土壤质量变化有较好的指示作用，可作为干旱荒漠绿洲土壤质量评价的一个生物指标。 |
| 英文摘要 | Desert oasis ecosystems are typically distributed in inland arid regions of northwestern China, and are home for many endemic and rare plant and animal species. The desert oasis ecosystem consists of three main geographical landscapes such as desert, oasis and desert-oasis transitional zone. In the desert area, Gobi desert shrubland is a dominant type of natural vegetation and is primarily subject to livestock grazing. In the transitional zone, sandy grassland is a dominant type of natural vegetation and livestock grazing is the most extensive land use. In the oasis area, about 80% of human populations inhabiting in this area, irrigated agriculture depending on water resources originating from ice and snow cover of the high mountains is the primary land use type. Since the early 1970s, most of the inland arid regions in northwest China have experienced a significant land-use history. One hand, rapid population growth in these arid regions has led to large-scale conversion of natural sandy grasslands to agricultural land in the edge of the oasis. On the other hand, large areas of natural grassland in the desert-oasis transitional zone were converted into different types of sand-fixing shrublands, or forest plantations for protecting the oasis ecosystems. Consequently, a variety of ecological patches has been established in the desert oasis landscape, creating a diverse landscape structure.\nChanges in land-cover and management regime can significantly influence the recruitment and assembly of ground or soil fauna communities by altering both biotic and abiotic environmental conditions, resulting in large changes in the structure of ground/soil fauna communities. These changes may ultimately influence ecosystem functions. However, littler is known about the underlying mechanisms of how long-term (at least more than two decades) land-cover change and land management practices (irrigation and fertilization) interact to sharp the assembly process of ground/soil fauna communities through complex interactions between them in this desert oasis ecosystem. In particular, few studies have quantitatively evaluated the relative importance of land-cover change (as indicated by ground cover), irrigation and fertilization management for the assembly of ground/soil fauna communities.\nThis study used a natural experimental approach based on land-use history that had occurred over several decades in the study area to explore the responses of ground/soil fauna assemblages to long-term land-cover change and management disturbances. Six major land-use types were selected for the comparative study. The study system included a natural grassland (control) and five differently managed artificial systems (21-year-old planted shrubland (Haloxylon ammodendron) without any management, 28-year-old Poplar (Populus simonii) and 33-year-old Pinus (Pinus sylvestris var. mongolica) plantations with irrigation, as well as 27- and 100-year-old croplands with irrigation and fertilization) converted from natural grassland. We investigated the abundance and composition of ground/soil fauna assemblages in six habitats during the growing season of 2009. The data were used to quantify the interactive effects of long-term land-cover change and land management on community assembly, and to assess how these effects varied among different components of the assemblages. We also assessed the biological indicator function of different soil fauna groups to environmental changes. The main results are summarized as follows: \n (1) Ground/soil fauna assemblages differed remarkably among three geographical landscapes of desert, oasis and desert-oasis transitional zone. In the desert area, the most abundant taxa in the ground arthropod assemblage were Teneberionidae (63%) and Formicidae (24%) and those in the soil fauna assemblage were Lohmannidae (37%), Isotomidae (19%) and Lealapidae (8%). In the transitional zone, the most abundant taxa of the ground arthropod assemblage were Formicidae (35%) and Lycosidae (16%) and those of the soil fauna assemblage were Lohmannidae (26%), Isotomidae (12%) and Oppiidae (11%). In the oasis area, the most abundant taxa in the ground arthropod assemblage were Formicidae (28%), Carabidae (28%) and Lycosidae (14%) and those in the soil fauna assemblage were Isotomidae (41%), Entomobriyidae (9%) and Lealapidae (7%). In addition, the desert area had higher abundance and taxa richness of the ground arthropod community than the oasis area and the desert-oasis zone, while the oasis area and the desert-oasis zone was higher in the abundance and taxa richness of soil fauna communities than the desert area.\n(2) The conversion of natural grasslands to unmanaged H. ammodendron shrublands did not cause large changes in abundance and taxa richness of ground/soil fauna communities, while converting natural grasslands to managed Poplar and Pinus plantations and croplands resulted in significant increases in abundance and taxa richness of ground/soil fauna communities. This indicates that the effects of land-cover change on community assembly were more pronounced in the presence than in the absence of land management practices.\n(3) Multivariate analysis showed that the composition of ground/soil fauna communities was significantly affected by vegetation cover, irrigation and fertilization management, but their relative contributions to the assembly of ground/soil fauna communities varied significantly. Overall, the relative contribution of irrigation disturbance to variation in community assembly was far greater than did fertilization and vegetation cover, suggesting that irrigation (water input) is the most important structuring force in ground/soil fauna communities in this arid desert ecosystem.\n(4) Path analysis showed that the abundance of ground arthropod communities was significantly influenced by the combination of vegetation cover, irrigation and fertilization, but this effect on the richness of ground arthropod communities was not statistically significant. Irrigation, fertilization and vegetation cover affected, directly and indirectly, the abundance of ground arthropods, but the total effect (estimated as the sum of direct and indirect effects) irrigation was greatest, followed in decreasing order by vegetation cover and fertilization. The abundance and richness of soil fauna communities were significantly affected by the combination of irrigation, fertilization and vegetation cover. Irrigation had strong positive direct effects on soil fauna community abundance and richness, but fertilization and vegetation cover affected soil fauna community abundance and richness indirectly through interactive effects with irrigation.\n(5) Partial CCA showed the key environmental variables affecting the distribution of ground arthropod communities were identified to be soil organic carbon (with net contribution of 53%), plant litter production (29%), pH (9%), soil water content (9%) and soil sand content (7%), while those affecting the distribution of soil fauna communities were soil organic carbon(44%), plant litter production (22%), soil water content(9%), pH (5%), soil temperature(4%) and soil microbial biomass carbon (4%).\n(6) Our results also showed that mature managed Poplar and Pinus plantations can effectively preserve the abundance and diversity of soil fauna assemblages. Thus, creating managed forestlands is most likely an important management tool in maintaining relatively intact soil fauna species pools in desert oasis landscapes.\n(7) BSQ (Biological Soil Quality) index values of soil arthropod communities were 67.2, 53.1, 117.7, 89.7, 142.4 and 180.3 for natural grassland, planted H. ammodendron shrubland, Poplar plantation, Pinus plantation, 27-year-old cropland and 100-year-old cropland, respectively. The fact that BSQ index values were significantly correlated to soil water content, soil temperature, soil texture, total nitrogen, microbial biomass carbon and soluble salt content suggests that this index can be used for a good indicator of environmental changes (soil quality change in particular) in desert oasis ecosystems.\n(8) We found significant differences in the responses of different soil arthropod groups to environmental changes. Groups of Geophilomorpha, Isotomidae, Entomobriyidae, Sminthuridae, Thripidae, Japygidae, Carabidae, Elateridae, Curculionidae, Scarabaeoidea, Chironomidae and Noctuidae were very sensitive to soil temperature that could be used for good indictors of changes in soil temperature. Groups of Lithobiomorpha, Acari, Hypogastruridae, Japygidae, Staphylinidae and Curculionidae were very sensitive to soil water and can be used for good indicators of changes in soil water availability. Groups of Geophilomorpha, Lithobiomorpha, Acari, Isotomidae, Sminthuridae, Staphylinidae, Curculionidae and Therevidae were very sensitive to soil texture and can be used for good indicators of change in soil texture. Groups of Lithobiomorpha, Scolopendrellidae, Acari, Entomobriyidae, Hypogastruridae, Staphylinidae, Therevidae and Dolichopodidae were sensitive to soil salinity and can be used for good indicators of changes in saline environments. Groups of mites, Hypogastruridae, Sminthuridae, Neelidæ, Japygidae, Staphylinidae, Chironomidae, Therevidae and Dolichopodidae were sensitive to soil nitrogen content and can be used for good indicators of changes in soil nitrogen availability. |
| 中文关键词 | 黑河流域 ; 土地覆被变化 ; 管理扰动 ; 地面节肢动物 ; 土壤动物 |
| 英文关键词 | Heihe river basin land cover change management disturbances ground arthropods soil arthropod fauna |
| 语种 | 中文 |
| 国家 | 中国 |
| 来源学科分类 | 生态学 |
| 来源机构 | 中国科学院西北生态环境资源研究院 |
| 资源类型 | 学位论文 |
| 条目标识符 | http://119.78.100.177/qdio/handle/2XILL650/287031 |
| 推荐引用方式 GB/T 7714 | 刘继亮. 黑河中游土地覆被变化与管理对地面/土壤动物群落演变的驱动机制[D]. 中国科学院大学,2012. |
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