Sonoma Chipmunk Predicted Habitat - CWHR M059 [ds2517]

<div style='text-align:Left;'><div><div><p><span>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: </span></p><p><span>1) a statewide, best-available vegetation map (FVEG); </span></p><p><span>2) GIS data representing a species’ range; </span></p><p><span>3) the CWHR database of habitat suitability values for over 700 terrestrial vertebrate species. </span></p><p><span>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. </span></p><p><span>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 </span><a href='https://www.wildlife.ca.gov/Data/CWHR' target='_blank' style='text-decoration:underline;' rel='nofollow ugc noopener noreferrer'><span>https://www.wildlife.ca.gov/Data/CWHR</span></a><span>. </span></p></div></div></div>

CWHR预测生境模型（CWHR Predicted Habitat Models）指各物种在其分布范围内的适宜生境预测区域。此类模型基于以下核心输入项构建：
1) 全州范围内可获取的最佳植被地图（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（0.34~0.66）与高（大于0.66），该分级基于物种三大生存必需条件——繁殖、觅食与隐蔽——的最大适宜性数值。需注意，此前版本的预测生境模型采用三大生存必需条件的平均值，以计算每种生境类型与阶段类别的总体适宜性得分。生境适宜性得分基于面积大于40英亩的生境斑块开发，其最佳解读场景为面积大于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）整合而成，整合了多项全州土地覆盖与区域植被测绘成果，这些成果于不同时期（大致1990年至发布之时）以不同分辨率完成。FVEG采用加州各区域当前可得的最一致数据。制定了决策规则，用于在重叠区域中确定优先采用的图层。通过转换对照表，依据CWHR生境类型分类系统为各类数据源赋予对应属性。将CWHR生境类型与FVEG进行属性匹配，即可提取各物种在其分布范围内具有非零适宜性数值的区域，从而生成一系列物种专属的适宜生境预测地图。

由于FVEG是全州各类土地覆盖评估成果的整合集合，不同物种乃至广布物种的不同区域间，其适宜生境预测能力可能存在差异。尽管此类地图代表了加州鱼类与野生动物部（California Department of Fish and Wildlife, CDFW）对CWHR系统内任意给定物种适宜生境存在性的最佳估算，但仍受多项因素限制：1) 特定区域内植被地图的精度与分辨率；2) 景观的动态性——火灾与其他干扰事件的发生频率高于测绘工作的追踪能力；3) 专家知识的时效性，尤其是在物种适应不断变化的土地与气候条件、其他物种种群分布发生偏移的场景下；4) 覆盖物种种群完整分布范围的代表性样本中，物种专属调查的开展频率；5) 复合种群动态——即种群因各类相互作用与环境响应所导致的其栖息环境内的种群迁移变化。

CWHR预测生境模型的命名依据为分配给每个物种的4位字母数字CWHR ID（亚种或其他亚分类单元为5位）。此外还设有“CWHR修订跟踪表（CWHR Revision Tracking Table）”，其中包含每个物种的相关记录，包括其CWHR ID、学名、通用名、分布范围与生境模型数据的修订历史。CWHR物种种群分布模型、预测生境模型、全州所有CWHR生境类型的GIS数据，以及CWHR修订跟踪表，均可在https://www.wildlife.ca.gov/Data/CWHR下载。