Fluvial Fish Richness Metrics for Stream Reaches of the NHDPlusV2.1 in the Conterminous United States

This geopackage contains 18 fluvial fish species richness for ~2.3 million stream reaches from the NHDPlusV2.1 in the Conterminous United States. Metrics were developed using 415 fluvial fish species distribution models and highlight four types of summary metrics including all modeled species, migratory species, species of greatest conservation need, and fish species. Nine metrics are counts of species modeled as present for the stream reach, while nine metrics are a normalized representation of the metrics. The normalization process calculates the percent of all designated species modeled in a geographic extent that are present at a stream reach. Richness metrics for all modeled species and migratory summary types were normalized by level two hydrologic unit code drainage units (huc2). Summary types of game fish and Species of Greatest Conservation Need were normalized in a similar manner but using state boundaries.

本地理数据包（Geopackage）包含美国本土基于NHDPlusV2.1的约230万个河段的18项河流鱼类物种丰富度数据。本数据集的指标依托415个河流鱼类物种分布模型构建，涵盖四类汇总指标：全部建模物种、洄游性物种、重点保护物种（Species of Greatest Conservation Need）以及鱼类物种。其中9项指标为各河段内被建模为存在的物种数量，剩余9项指标为上述指标的归一化形式。归一化流程用于计算某一河段内，在其所属地理范围内建模的所有指定物种中，实际存在于该河段的物种占比。针对全部建模物种与洄游性物种两类汇总指标的丰富度度量，以二级水文单元代码（Hydrologic Unit Code, HUC）流域单元为分区进行归一化；而游钓鱼类与重点保护物种两类汇总指标则采用类似的归一化方式，但以州界作为地理分区依据。