For plant species of conservation concern, knowledge of changes in abundance through time is a minimum requirement for informed management. This information is usually acquired through on-the-ground monitoring, which entails counting individuals in defined areas over multiple years. Demographic studies, which involve tracking individual plants through time, are usually carried out at limited spatial scales and over shorter time frames than monitoring, but are more useful to management. In this study we explored the use of drone (UAV or unmanned aerial vehicle) imagery analysis as a tool for collecting demographic data for dwarf bear poppy (Arctomecon humilis), an endangered species restricted to gypsum outcrops in the northeastern Mojave Desert, USA. We obtained imagery at 15 m altitude during peak flowering at four populations in spring 2019. Each poppy plant in the imagery was georeferenced, measured and scored for flowering. To estimate reproductive output, we developed independent data sets relating plant diameter to flower number, then sampled to determine mean fruit set per flower and seeds per fruit. We used these relationships along with plant diameter and reproductive status for each plant in the drone imagery to estimate seed rain on an area basis across nine 0.6 ha demography plots at each population. This method enabled us to collect demographic data on >3,000 plants, including estimated production of ca. 3.7 million seeds, across >20 ha of habitat. We also analyzed imagery acquired in both 2018 and 2019 at two of the four populations and quantified recruitment, growth, and mortality of individual georeferenced plants. Our study is among the first to demonstrate the utility of drone imagery analysis in plant demographic studies. The method is most applicable for non-clonal perennial species with distinctive morphology that occur in habitats with low vegetative cover.

对于需要保护的植物物种，了解随着时间变化的丰度变化是知情管理的最低要求。这些信息通常是通过实地监测获得的，这需要对指定区域内的个人进行数年的计数。人口统计研究涉及随时间推移跟踪单个植物，通常在有限的空间范围内进行，并且比监测要在较短的时间范围内进行，但对管理更有用。在这项研究中，我们探索了使用无人机（UAV或无人机）影像分析作为收集矮人罂粟（Arctomecon humilis）人口统计数据的工具的用途。），一种濒临灭绝的物种，仅限于美国东北部的莫哈韦沙漠中的石膏露头。我们在2019年春季在四个种群的开花高峰期获得了海拔15 m处的图像。图像中的每种罂粟植物均已进行地理定位，测量和评分以进行开花。为了估算生殖产量，我们建立了独立的数据集，将植物直径与花序数联系起来，然后进行抽样以确定每朵花的平均坐果数和每朵果实的种子数。我们使用这些关系以及无人机图像中每种植物的植物直径和繁殖状态，在每个种群的9个0.6公顷人口统计学图上以面积为基础估算种子雨量。这种方法使我们能够收集超过3,000种植物的人口统计数据，包括大约2,000株的估计产量。370万颗种子，栖息地超过20公顷。我们还分析了2018年和2019年在四个种群中的两个种群获得的图像，并对单个地理参考植物的募集，生长和死亡率进行了量化。我们的研究是第一个证明无人机图像分析在植物人口统计研究中的实用性的研究。该方法最适用于植被覆盖度较低的生境中具有独特形态的非克隆多年生物种。