Application of UAV-Based Methodology for Census of an Endangered Plant Species in a Fragile Habitat

Abstract

Accurate census is essential for endangered plant management, yet lack of resources may make complete on-the-ground census difficult to achieve. Accessibility, especially for species in fragile habitats, is an added constraint. We examined the feasibility of using UAV (unmanned aerial vehicle, drone)-based imagery for census of an endangered plant species, Arctomecon humilis (dwarf bear-poppy), an herbaceous perennial gypsophile endemic of the Mojave Desert, USA. Using UAV technology, we captured imagery at both 50-m altitude (census) and 15-m altitude (validation) at two populations, White Dome (325 ha) and Red Bluffs (166 ha). The imagery was processed into orthomosaics that averaged 2.32 cm ground sampling distance (GSD) for 50-m imagery and 0.73 cm GSD for 15-m imagery. Putative poppy plants were marked in the 50-m imagery according to predefined criteria. We then used the 15-m imagery from each area to verify the identification accuracy of marked plants. Visual evaluation of the 50-m imagery resulted in errors of both commission and omission, mainly caused by failure to accurately identify or detect small poppies (<10 cm diameter). Higher-resolution 30-m altitude imagery (1.19 cm GSD) greatly reduced errors of commission. Habitat classification demonstrated that poppy density variation was closely tied to soil surface color. This study showed that drone imagery can potentially be used to census rare plant species with distinctive morphology in open habitats and understand their spatial distribution.

No place to hide: Rare plant detection through remote sensing

“…Direct detection can be carried out either by visual identification or by image classification methods that allow the detection of distinctive spectral features of the target species. Specifically, Fletcher and Erskine (2012) and Rominger and Meyer (2019) indices, has proven to be an effective alternative approach for their direct detection (Liu et al, 2018). For instance, the endangered Allium tricoccum Aiton (wild leek) and the endemic Agathis australis (D.Don) Lindl.…”

New tools for old problems — comparing drone- and field-based assessments of a problematic plant species

“…Drones, or UAS (unmanned aerial systems), are becoming a valuable tool for mapping problematic or endangered plant species (Alvarez-Taboada et al 2017 ; Rominger and Meyer 2019 ). UAS are cost friendly and allow flexible application in space and time, and very-high-resolution (VHR) image data can be acquired within 1 h by a single person, e.g., before or during a field survey.…”

Swarm Intelligence Application to UAV Aided IoT Data Acquisition Deployment Optimization

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