An estimate of Ephedra californica shrub densities at Elkhorn Plain, Carrizo National Monument, California

Google imagery was used to assess the range of Ephedra californica shrub densities at the Elkhorn Plain in Carrizo Plain National Monument. There is an extensive ephedra parkland beginning where Simmler Soda Lake Road becomes Elkhorn Road on the east side of the Monument. Imagery was regularly sampled at the scale of field plots in a supporting field experiments. Circular plots 10m in radius were gridded onto imagery and regularly, and randomly placed moving from the start of Elkhorn Road to the end of the parkland sampled in the associated ecological surveys. The purpose of this simple exercise was to validate field counts of shrubs.

本研究采用谷歌影像（Google imagery），对卡里佐平原国家纪念碑（Carrizo Plain National Monument）内埃尔克霍恩平原（Elkhorn Plain）的加州麻黄（Ephedra californica）灌丛密度分布范围进行评估。在该纪念碑东侧，西姆勒苏打湖路（Simmler Soda Lake Road）与埃尔克霍恩路（Elkhorn Road）的衔接路段起始处，分布有一片广袤的麻黄灌丛群落。研究以配套野外实验的样地（field plots）尺度对影像开展系统采样：将半径10米的圆形样地网格化匹配至影像范围，并从埃尔克霍恩路起点至该灌丛群落终点，按规则且随机的方式布设样地，用于配套的生态调查（ecological surveys）采样。本项简易工作的核心目的，在于验证野外灌丛计数结果的准确性。