Narrow-Faced Kangaroo Rat Predicted Habitat - CWHR M102 [ds2556]

<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>

加州野生动物栖息地关系（California Wildlife-Habitat Relationships, CWHR）预测栖息地模型，指代各物种分布范围内的潜在适宜栖息地区域。此类模型基于以下核心输入项构建：
1）全州范围内最优可用植被图（FVEG）；
2）表征物种分布范围的地理信息系统（Geographic Information System, GIS）数据；
3）涵盖700余种陆生脊椎动物栖息地适宜性分值的CWHR数据库。

栖息地适宜性等级分为低（非零分值小于0.34）、中（0.34~0.66）与高（大于0.66）三类，其划分依据为物种3类生命必需条件（繁殖、觅食与隐蔽）的最大适宜性分值。需注意，此前版本的该预测栖息地模型曾以3类生命必需条件的平均分值，来计算各栖息地类型与阶段类别的综合适宜性得分。本数据集的栖息地适宜性分值基于面积大于40英亩的栖息地斑块生成，其解读的最优适用场景为面积大于200英亩的栖息地斑块。

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，其数据源涵盖多项全州尺度与区域尺度的土地覆盖及植被测绘工作，这些工作开展于1990年左右至数据集发布之时的不同时段，且分辨率各异。FVEG针对加州各区域采用当前可得的最新且一致的数据集。研究人员制定了决策规则，用于确定重叠区域中各数据图层的优先级，并通过跨数据源映射对照表（Crosswalks）将各类数据源按照CWHR栖息地类型分类体系进行属性赋值。将FVEG数据集赋予CWHR栖息地类型属性后，即可在各物种的分布范围内提取适宜性分值非零的区域，进而生成一系列针对特定物种的预测适宜栖息地地图。

由于FVEG是加州境内多项不同土地覆盖评估工作的整合产物，其判定适宜栖息地的预测能力会因物种而异，对于分布范围广泛的物种，其预测能力甚至可能随区域不同而产生差异。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体系内各物种适宜栖息地存在情况的最优估算，但该类地图仍受多项因素限制：1）特定区域内植被图的精度与分辨率；2）景观的动态特性——火灾与其他干扰事件对栖息地条件的改变频率，远超测绘工作的追踪能力；3）专家知识的时效性，尤其是在物种适应土地与气候条件变化、其他物种分布范围发生偏移的背景下；4）针对物种全分布范围代表性样地开展物种专项调查的频次；5）集合种群动态——该概念描述了种群因各类相互作用与响应而在栖息地环境中发生的空间位移。

表征预测适宜栖息地的CWHR地理信息系统数据，不得用于判定特定地点是否存在某一物种。CWHR预测栖息地模型的命名规则为，采用为各物种分配的4位字母数字混合CWHR标识符（亚种或其他下级类群的标识符为5位）。另有一份“CWHR修订追踪表”，其中包含各物种的相关记录，包括其CWHR标识符、学名、俗名，以及分布范围与栖息地模型数据的修订历史。CWHR物种分布模型、预测栖息地模型、涵盖全州所有CWHR栖息地类型分布的地理信息系统数据，以及CWHR修订追踪表，均可通过以下链接下载：<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>。