Using photogrammetry to create virtual permanent plots in rare and threatened plant communities

Abstract

PremiseMany plant communities across the world are undergoing changes due to climate change, human disturbance, and other threats. These community‐level changes are often tracked with the use of permanent vegetative plots, but this approach is not always feasible. As an alternative, we propose using photogrammetry, specifically photograph‐based digital surface models (DSMs) developed using structure‐from‐motion, to establish virtual permanent plots in plant communities where the use of permanent structures may not be possible.MethodsIn 2021 and 2022, we took iPhone photographs to record species presence in 1‐m2 plots distributed across alpine communities in the northeastern United States. We then compared field estimates of percent coverage with coverage estimated using DSMs.ResultsDigital surface models can provide effective, minimally invasive, and permanent records of plant species presence and percent coverage, while also allowing managers to mark survey locations virtually for long‐term monitoring. We found that percent coverage estimated from DSMs did not differ from field estimates for most species and substrates.DiscussionIn order to continue surveying efforts in areas where permanent structures or other surveying methods are not feasible, photogrammetry and structure‐from‐motion methods can provide a low‐cost approach that allows agencies to accurately survey and record sensitive plant communities through time.

3D documentation and classification of incense tree Aquilaria sinensis (Lour.) Spreng. wounds by photogrammetry and its potential conservation applications

“…The cost of 3D photogrammetry methods for reconstructing 3D models for plant documentation is lower than that of other methods (Andújar et al., 2018 ; Dong et al., 2021 ). In addition, 3D photogrammetry is nondestructive during plant observation and measurement (Arief et al., 2021 ; Bauwens et al., 2017 ; Mokroš et al., 2020 ; Tirrell et al., 2023 ). Therefore, 3D photogrammetry has great potential for use in tree wound 3D documentation.…”

Advances in plant imaging across scales

“…Beyond individual specimens, the uses of digital imaging and photogrammetry methods are also explored by Tirrell et al (2023) for their increasing value in integrating systematics, conservation, plant ecology, and the broader study of plant diversity. The authors propose and demonstrate the use of photogrammetry as a nondestructive protocol for critical long‐term monitoring of research plots while reducing the possibility for inadvertent damage to sensitive, difficult‐to‐access, unpermitted, or otherwise inaccessible plant communities.…”