San Clemente Island Fox Range - CWHR M150b [ds3289]

CWHR species range datasets represent the maximum current geographic extent of each species within California. Ranges were originally delineated at a scale of 1:5,000,000 by species-level experts more than 30 years ago and have gradually been revised at a scale of 1:1,000,000. Species occurrence data are used in defining species ranges, but range polygons may extend beyond the limits of extant occurrence data for a particular species. When drawing range boundaries, CDFW seeks to err on the side of commission rather than omission. This means that CDFW may include areas within a range based on expert knowledge or other available information, despite an absence of confirmed occurrences, which may be due to a lack of survey effort. The degree to which a range polygon is extended beyond occurrence data will vary among species, depending upon each species’ vagility, dispersal patterns, and other ecological and life history factors. The boundary line of a range polygon is drawn with consideration of these factors and is aligned with standardized boundaries including watersheds (NHD), ecoregions (USDA), or other ecologically meaningful delineations such as elevation contour lines. While CWHR ranges are meant to represent the current range, once an area has been designated as part of a species’ range in CWHR, it will remain part of the range even if there have been no documented occurrences within recent decades. An area is not removed from the range polygon unless experts indicate that it has not been occupied for a number of years after repeated surveys or is deemed no longer suitable and unlikely to be recolonized. It is important to note that range polygons typically contain areas in which a species is not expected to be found due to the patchy configuration of suitable habitat within a species’ range. In this regard, range polygons are coarse generalizations of where a species may be found. This data is available for download from the CDFW website: https://www.wildlife.ca.gov/Data/CWHR. The following data sources were collated for the purposes of range mapping and species habitat modeling by RADMAP. Each focal taxon’s location data was extracted (when applicable) from the following list of sources. BIOS datasets are bracketed with their “ds” numbers and can be located on CDFW’s BIOS viewer: https://wildlife.ca.gov/Data/BIOS. California Natural Diversity Database, Terrestrial Species Monitoring [ds2826], North American Bat Monitoring Data Portal, VertNet, Breeding Bird Survey, Wildlife Insights, eBird, iNaturalist, other available CDFW or partner data.加州野生动物栖息地关系（CWHR）物种分布数据集呈现了加利福尼亚州内各物种当前的最大地理分布范围。该分布范围最初由物种级专家于30余年前以1:5000000的比例尺绘制完成，后续逐步以1:1000000的比例尺进行修订。物种分布范围的界定会参考物种出现数据，但分布范围多边形（range polygons）可能会超出某一特定物种现存出现数据的边界。在绘制分布边界时，加州鱼类和野生动物部（California Department of Fish and Wildlife, CDFW）秉持“宁多勿缺”的原则：即便因缺乏调查工作而未获得确认的物种出现记录，CDFW也可基于专家知识或其他可用信息，将相关区域纳入物种分布范围。分布范围多边形超出出现数据的程度会因物种而异，取决于各物种的扩散能力、扩散模式以及其他生态与生活史因素。分布范围多边形的边界线在绘制时会综合考量上述因素，并与标准化边界对齐，包括水文流域（国家水文数据集National Hydrography Dataset, NHD）、生态区（美国农业部United States Department of Agriculture, USDA）或其他具有生态意义的划分方式（如海拔等高线）。尽管CWHR数据集旨在呈现物种当前的分布范围，但一旦某一区域被纳入CWHR的物种分布范围，即便近数十年未出现过记录到的物种出现事件，该区域仍会保留在分布范围内。仅当专家指出某区域经多次调查后多年未被物种占据，或被认定不再适宜物种栖息且不太可能再次被定殖时，才会将其从分布范围多边形中移除。需要注意的是，由于物种分布范围内适宜栖息地呈斑块状分布，分布范围多边形通常会包含物种实际不会栖息的区域。就此而言，分布范围多边形仅是对物种可能分布区域的粗略概括。该数据集可从CDFW官网下载：https://www.wildlife.ca.gov/Data/CWHR。RADMAP为开展分布范围制图与物种栖息地建模工作，整合了以下数据源：各目标类群的位置数据（如适用）均提取自下述来源。BIOS数据集以其“ds”编号标注，可通过CDFW的BIOS查看器访问：https://wildlife.ca.gov/Data/BIOS。具体数据源包括加利福尼亚自然多样性数据库、陆地物种监测[ds2826]、北美蝙蝠监测数据门户、VertNet、繁殖鸟类调查、Wildlife Insights、eBird、iNaturalist，以及其他可用的CDFW或合作方数据。