Ecoregions of North America

Ecoregions are areas where ecosystems (and the type, quality, and quantity of environmental resources) are generally similar. This ecoregion framework is derived from Omernik (1987) and from mapping done in collaboration with EPA regional offices, other Federal agencies, state resource management agencies, and neighboring North American countries. Designed to serve as a spatial framework for the research, assessment, and monitoring of ecosystems and ecosystem components, ecoregions denote areas of similarity in the mosaic of biotic, abiotic, terrestrial, and aquatic ecosystem components with humans being considered as part of the biota. These regions are critical for structuring and implementing ecosystem management strategies across Federal agencies, state agencies, and nongovernmental organizations that are responsible for different types of resources within the same geographic areas.
Ecoregions are identified by analyzing the patterns and composition of biotic and abiotic phenomena that affect or reflect differences in ecosystem quality and integrity. These phenomena include geology, landforms, soils, vegetation, climate, land use, wildlife, and hydrology. The relative importance of each characteristic varies from one ecological region to another regardless of the hierarchical level. A Roman numeral classification scheme has been adopted for different hierarchical levels of ecoregions, ranging from general regions to more detailed.
North America has been divided into:

15 broad, level I ecological regions;
50 level II ecological regions intended to provide a more detailed description of the large ecological areas nested within the level I regions; and
182 Level III ecoregions, which are smaller ecological areas nested within level II regions.

Select a section for additional details about each level, or a list of links to downloadable maps and GIS data files. Resources in this dataset:Resource Title: Index of /EPADataCommons/ORD/Ecoregions/. File Name: Web Page, url: ftp://newftp.epa.gov/EPADataCommons/ORD/Ecoregions/ FTP directory of Ecoregion files

生态区是指生态系统中（以及环境资源的类型、质量和数量）总体相似的区域。本生态区框架源于 Omernik (1987) 的研究，并联合美国环境保护署区域办公室、其他联邦机构、州资源管理机构以及邻近的北美国家所进行的制图工作。该框架旨在作为生态系统及其组成部分研究、评估和监测的空间框架，生态区界定了生物、非生物、陆地和水生生态系统组件在镶嵌图案中的相似区域，其中人类被视为生物群落的一部分。这些区域对于在联邦机构、州机构以及负责同一地理区域内不同类型资源的非政府组织中构建和实施生态系统管理策略至关重要。生态区通过分析影响或反映生态系统质量和完整性的生物和非生物现象的模式和组成来识别。这些现象包括地质、地形、土壤、植被、气候、土地利用、野生动物和水利。每个特征的重要性在不同生态区域之间有所差异，无论其层级水平如何。已采用罗马数字分类方案对不同层级的生态区进行分类，范围从一般区域到更详细的区域。北美地区已被划分为：15个广泛的、一级生态区；50个二级生态区，旨在对一级区域内部的大型生态区域提供更详细的描述；以及182个三级生态区，这些生态区是嵌套在二级区域内的较小生态区域。可选择某一章节以获取每个层级的详细信息，或列出可下载的地图和GIS数据文件的链接。本数据集包含的资源：资源标题：/EPADataCommons/ORD/Ecoregions/索引。文件名：网页，URL：ftp://newftp.epa.gov/EPADataCommons/ORD/Ecoregions/，FTP目录包含生态区文件。