Cross-Site: Earthworms and Soil Processes In North American Ecosystems

跨站点：北美生态系统中的蚯蚓和土壤过程

• 批准号: 9527365
• 负责人: Paul Hendrix
• 金额: $ 20万
• 依托单位: University of Georgia Research Foundation Inc
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-10-01 至 1999-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9527365&HistoricalAwards=false
• 关键词: Cross; Site; Earthworms; Soil; Processes

Influences of earthworms on soil processes in agricultural and pastoral systems are well recognized but there is considerably less information about their importance in wildland ecosystems such as forests, grasslands and savannas. Furthermore, very little is known about the ecology of native earthworm species in North America, even though they are prevalent in a number of areas unaffected by Pleistocene glaciations. The few existing studies indicate that where they are abundant, these organisms can have significant effects on soil structural properties and on nutrient transformations. However. the relative importance of native versus invasive exotic earthworm species remain virtually unknown. This proposal requests funding for a cross-site investigation of native and exotic earthworms, to determine if native species are more efficient than exotic species in nutrient processing in undisturbed ecosystems. They also will determine if disturbance sets the stage for invasion by exotic earthworms, which may be more competitive than natives but less effective in nutrient cycling. Th ese ideas will be tested in two phases over a three year period at three LTER sites (Coweeta Hydrologic Laboratory, Konza prairie Research Natural Area and Luquillo Experimental Forest) and one non-LTER site (Apalachicola National Forest). They will undertake field surveys and collections in a variety of habitats, and will initiate field enclosure experiments using 13C- and 14N- enriched substrates. Together, these two phases of work optimize the use of stable isotopes in field studies--first, as survey tools to characterize and identify important species and patterns of resource utilization across sites; and then as biogeochemical tracers to elaborate earthworm-microbial interactions and to quantify influences of various earthworm species on C and N dynamics. Results from this study will greatly expand their understanding of earthworm ecology, interactions between native and exotic species, and influences of both groups on soil nutrient processes across a broad range of ecosystems.

蚯蚓对农业和畜牧业系统土壤过程的影响是公认的，但有相当少的信息，他们在荒地生态系统，如森林，草原和稀树草原的重要性。 此外，人们对北美本土的白蛉物种的生态学知之甚少，尽管它们在一些未受更新世冰川影响的地区很普遍。 现有的少数研究表明，在这些生物丰富的地方，这些生物可对土壤结构特性和养分转化产生重大影响。 然而.本地物种与外来入侵物种的相对重要性实际上仍然未知。 该提案要求为本地和外来蚯蚓的跨站点调查提供资金，以确定在未受干扰的生态系统中，本地物种是否比外来物种在营养加工方面更有效。 他们还将确定干扰是否为外来蚯蚓的入侵奠定了基础，外来蚯蚓可能比本地蚯蚓更具竞争力，但在养分循环中效率较低。 这些想法将在三年内分两个阶段在三个LTER地点（考埃塔水文实验室、孔扎草原研究自然区和卢基略实验森林）和一个非LTER地点（阿巴拉契科拉国家森林）进行测试。 他们将在各种生境进行实地调查和收集，并将使用富含13 C和14 N的基质进行实地封闭实验。 总之，这两个阶段的工作优化了稳定同位素在实地研究中的使用-首先，作为调查工具，以表征和确定重要的物种和跨站点的资源利用模式;然后作为地球化学示踪剂，阐述蚯蚓-微生物相互作用，并量化各种蚯蚓物种对C和N动态的影响。 这项研究的结果将大大扩展他们对生态学的理解，本地和外来物种之间的相互作用，以及这两个群体对广泛生态系统土壤养分过程的影响。