Tehachapi Slender Salamander Predicted Habitat - CWHR A018 [ds1985]

CWHR Predicted Habitat Models represent areas of predicted suitable habitat for each species within its range. These models are built from the following principal inputs: 1) a statewide, best-available vegetation map (FVEG); 2) GIS data representing a species’ range; 3) the CWHR database of habitat suitability values for over 700 terrestrial vertebrate species. Habitat suitability ranks of Low (non-zero values less than 0.34), Medium (0.34-0.66), and High (greater than 0.66) are based on the maximum suitability value across the 3 species life requisites: reproduction, feeding, and cover. Note that previous versions of these Predicted Habitat Models used an average across the 3 life requisites in order to obtain an overall suitability score for each habitat type and stage class. Habitat suitability scores were developed based on habitat patch sizes greater than 40 acres in size and are best interpreted for habitat patches greater than 200 acres in size. The FVEG landcover dataset is an aggregation of multiple statewide landcover and regional vegetation mapping efforts, conducted at different points in time (approximately 1990 up to time of publishing) and at various resolutions, compiled by the California Department of Forestry and Fire Protection (CALFIRE). FVEG uses the most current and consistent data available for each region of the state. Decision rules were developed that controlled which layers were given priority in areas of overlap. Crosswalks were used to attribute the various data sources according to the CWHR habitat-type classification system. Attributing FVEG with CWHR habitat types allows for the extraction of areas with non-zero suitability values for each species within the bounds of its range, creating a series of maps of predicted suitable habitat which are species-specific. Because FVEG is an amalgam of disparate landcover assessment efforts across the state, the predictive power for determining suitable habitat will vary between species, and possibly even regionally for species which are widely distributed. While these maps represent CDFW’s best estimate of the presence of suitable habitat for any given species in the CWHR system, these maps are also limited by several factors: 1) the accuracy and resolution of vegetation maps in a given region; 2) the dynamic nature of the landscape in which fire and other disturbance events alter conditions at a greater frequency than mapping efforts can track; 3) the currency of expert knowledge, particularly as species adapt to changing land and climate conditions and the shifting of other species’ ranges; 4) the frequency of species-specific surveys across a representative sample of a species’ entire range; 5) metapopulation dynamics, which describes the shifting of populations within their environment as result of numerous types of interactions and responses. CWHR GIS data representing predicted suitable habitat should not be used to indicate the presence or absence of a particular species at any specific site. CWHR predicted habitat models are named according to the 4-character alpha-numeric CWHR ID assigned to each species (5 characters in the case of subspecies or other sub-taxa). There is also a “CWHR Revision Tracking Table” containing a record for each species, its CWHR ID, scientific name, common name, and range and habitat model data revision history. CWHR species range models, predicted habitat models, and GIS data of the statewide distribution of all CWHR habitat types, along with the CWHR revision tracking table, are available for download at https://www.wildlife.ca.gov/Data/CWHR.CWHR预测生境模型（CWHR Predicted Habitat Models）代表各物种种群分布范围内的潜在适宜生境区域。此类模型基于以下三类核心输入构建：1）全州范围内可获取的最优植被图（FVEG）；2）表征物种种群分布的地理信息系统（GIS）数据；3）涵盖700余种陆生脊椎动物生境适宜性数值的CWHR数据库。 生境适宜性等级划分为低（非零数值小于0.34）、中（0.34至0.66）、高（大于0.66），其划分依据为物种3类生命需求——繁殖、觅食与隐蔽——对应的最大适宜性数值。需注意，此前版本的预测生境模型采用这3类生命需求的平均值，以计算每种生境类型与阶段类别的整体适宜性得分。生境适宜性得分基于面积大于40英亩的生境斑块开发，最适用于面积大于200英亩的生境斑块。 FVEG土地覆盖数据集由加州林业与消防局（California Department of Forestry and Fire Protection, CALFIRE）整合多项全州土地覆盖与区域植被制图工作成果而成，这些工作于不同时段（大致1990年至本数据集发布之时）开展，分辨率各异。FVEG采用加州各区域当前可获取的最精准、一致的数据，并制定决策规则以处理重叠区域内图层的优先级问题；同时采用映射对照表（Crosswalks）依据CWHR生境类型分类体系为各类数据源赋予属性。将FVEG与CWHR生境类型完成属性关联后，即可在物种分布范围内提取具有非零适宜性数值的区域，进而生成一系列针对特定物种的潜在适宜生境地图。 由于FVEG是全州各类土地覆盖评估工作的整合成果，不同物种乃至同一物种在不同区域的生境适宜性预测能力会存在差异。尽管此类地图代表了加州鱼类与野生动物部（CDFW）对于CWHR体系内任意物种的适宜生境存在情况的最优估算，但仍受多项因素限制：1）特定区域植被图的精度与分辨率；2）景观的动态性——火灾与其他干扰事件改变生境条件的频率高于制图工作的更新频率；3）专家认知的时效性，尤其是在物种适应土地与气候变迁、其他物种种群分布发生转移的背景下；4）针对物种完整分布范围的代表性样本开展物种特异性调查的频率；5）集合种群动态——即种群因各类相互作用与环境响应而在其栖息环境中发生的位移变化。 CWHR预测生境的GIS数据不得用于判定任意特定地点是否存在某一物种。CWHR预测生境模型以分配给每个物种的4位字母数字组合CWHR ID命名（亚种或其他次级分类单元的ID为5位）。此外还设有“CWHR修订跟踪表”，其中包含每个物种的CWHR ID、学名、通用名、分布范围及生境模型数据的修订历史记录。 CWHR物种种群分布模型、预测生境模型、全州所有CWHR生境类型全域分布的GIS数据，以及CWHR修订跟踪表，均可从https://www.wildlife.ca.gov/Data/CWHR下载获取。